Scipedia: Documents published in 2021

The Floor Stiffness Effect on Vulnerability Assessments and Intervention Designs of Historic Buildings: the Case Study of the “Procuratie Vecchie” in Venice, Italy

Scipedia content — Tue, 30 Nov 2021 14:52:25 +0100

In the Italian seismic scenario, and beyond, interventions on existing buildings focused on the evaluation and reduction of seismic risk of cultural heritage have gained more and more importance in the engineering field.
Therefore, for the designer it becomes increasingly useful to have a methodology that allows to carry out, in the study of an existing structure behavior, the vulnerability assessment of both the actual state and the design state, evaluating the adequacy of potential intervention of seismic improvement.
In this paper some phases of this methodology are presented in the context of the restoration work started in November 2017, and currently in progress, of the historical building of Procuratie Vecchie in Piazza San Marco in Venice, with particular focus on the consolidation intervention of the timber floors which satisfy the conservation requirements imposed by the Superintendence of Venice. Actually, the influence of floor diaphragms on structural behavior of existing masonry building subjected to seismic action is critically discussed with particular reference to the effects of in-plane stiffness of floors on the seismic distribution of forces on lateral walls and on the out–of–plane mechanism of the walls.

The Dome of the Temple of Diana in Baiae: Geometry, Mechanics and Architecture

Scipedia content — Tue, 30 Nov 2021 14:52:16 +0100

The purpose of this paper, which is part of a multi-disciplinary research project started in 2018 [1], is to investigate both the geometry and stability of the dome of the temple of Diana, which partially survived for many centuries. Important observations made by De Angelis d’Ossat [2] and results of the architectonic survey performed by Rakob [3] will be presented and discussed; they introduce the delicate issue concerning the identification of the geometric profile of the dome, on which its structural stability depends. It is the Authors’opinion that ascertaining the geometric profile of a dome is not only a matter of measuring, but also of historical context, geometric knowledge and traditions in construction. Thus, by taking all the above issues into account and making use of data from a recent architectonic survey [1], this paper searches for possible connections with consolidated traditions of the Sassanid architecture imported by the Emperor Alexander Severus, verifies the geometric knowledge presumed to have been acquired by the time of the dome’s construction and identifies the most probable theoretical design: the dome’s meridian profile is a unique curve – to be precise, a parabola, the best approximation of a catenary. Thus, once the profile of the dome has been identified, structural analysis confirms not only the stability of the dome, but also that the Romans were aware of the dome’s behaviour in relation to the construction solutions adopted.

The Dar al Consul Complex in Jerusalem: Improving the Living Conditions and the Structural Capacity

Scipedia content — Tue, 30 Nov 2021 14:52:05 +0100

The Custody of the Holy Land, with own and EU funds, and in Partnership with UNHabitat, is implementing a comprehensive rehabilitation Project in Dar Al Consul civic and residential complex, which is one of the Custody properties in the heart of the Old City of Jerusalem. The complex, which corresponds to a urban block of relevant dimensions (80 x 50m x 5 levels above and below the ground) and intersects the Roman Cardo, consists of 40 Houses and a basement floor used as a closed storage at the street level, besides sharing part of its ground floor with the old city market. Prior to the planned rehabilitation works in the houses - to improve the living conditions – and in the basement - to be reused as public space- the Custody intended to conduct a safety assessment of the complex for both static and seismic loads, in order to integrate any needed strengthening work within the planned restoration activities. A series of technical activities were then carried out aimed at evaluating the safety conditions of the structures. A comprehensive investigation campaign was planned and executed in order to characterize the structural materials and define the constructive techniques. Several modelling strategies of the structures, which resulted particularly complex for the historical stratification of the site, were then used. By means of numerical modelling, the stresses were defined in the masonry elements by weight and by occurrence of a seismic event, allowing to highlight the insufficient safety conditions of the main resisting elements of the basement and subsequently to define adequate structural consolidation strategies. During the works, the need for archaeological excavation implied further engineering efforts in order to allow deep excavations avoiding any harm to the above positioned levels and structural portions.

The Damage Survey of Cultural Built Heritage Between Simplified Procedures and Needs for Implementation: the Case Study of Emilia-Romagna Cemeteries

Scipedia content — Tue, 30 Nov 2021 14:51:56 +0100

Seven years after the earthquake occurred in Emilia-Romagna, the planning phases related to the cultural heritage reconstruction are coming to a conclusion. At this point, the Agency for reconstruction - earthquake 2012 has launched an unprecedented process aimed at verifying, also through the recognition of the main critical issues, the simplified damage assessment procedures whose application has allowed an aware and sustainable management of the emergency. The Guidelines for the evaluation and reduction of seismic risk on Cultural Heritage, and the Directive 12/12/2013 “Procedures for management of activities for cultural heritage securing and safeguarding in the event of emergencies caused by natural disasters” of MiBAC identify as first cognitive procedure the compilation of sheet to provide vulnerabilities and damage level representation on
movable and immovable assets. In particular, they establish two important survey instruments: the A-Church and the B-Palaces sheets.
These are the only two instruments used between 2012 and 2013 for the damage level characterization of the cultural heritage caused by the “Emilia 2012” earthquake. The widespread use of these sheets has brought to light several problems that have negatively affected the successive economic assessment of the intervention. In fact, if these sheets well describe the vulnerabilities of the specialized types Churches or Palaces, they are ill suited to types with different features, which, in the Emilia-Romagna case, represent about 30% of damage cultural heritage numerically and economically. In particular, the most relevant sample in this set are the cemeteries.
After the analysis of sheets produced for the cemetery type, the need to implementation for the already consolidated procedures has become clear, in order to be able to manage the post-emergency phases on those types that, as cemeteries, represent an important part of the local cultural identity, but that are not addressed in existing tools.

The Column-Less Stair at Loretto Chapel in Santa Fe, New Mexico: Strength Analysis

Scipedia content — Tue, 30 Nov 2021 14:51:49 +0100

A spiral staircase in Loretto Chapel in Santa Fe, New Mexico, has no center column to provide structural strength and stability. Some estimates say that the stair should have collapsed at first use. Yet, the stair has been used daily since its genesis in 1878. Explanations of the strength of the structure varied from “basic mechanics” to “miracle”. This article presents a stress analysis of the stair using a finite element model. The loading is 16 persons on steps 1, 3, 5, …, 31 of the stair (as shown in an old photograph), the weight of the stair, and the weight of the railing. Stress computation was performed with a finite element model built and run in Abaqus CAE (Dassault Systemme, 2016). The analysis shows that the center spiral is severely stressed. The maximum Von Mises stress, which occurs near the top of the center spiral, is 1.7MPa. The ultimate strength of strong Engelmann spruce is 2.0MPa. The absence of the center column is significant because a center column would reduce the maximum stress in the stair to about 0.3MPa.

The CLT Panels in Structural Restoration: Characteristics and Technical Regulations

Scipedia content — Tue, 30 Nov 2021 14:51:38 +0100

Wood can represent a valid and important alternative to the most commonly used structural materials for the restoration of masonry buildings, with a view to efficient, effective and "conscious" renovation. Today, the modern technologies allows to overcome the structural limits of solid wood due to its own anisotropy. The use of composite wood elements makes possible to obtain excellent mechanical performances that consent to evaluate aspects such as the use of low environmental impact retrofit strategies. The aim of this work is the analysis of mechanical parameters related to CLT (cross laminated timber) panels in order to determine their possible use in the structural restoration of masonry buildings. The CLT panels consist of solid wood planks superimposed so that
each layer has the fibres rotated ninety degrees with respect to the adjacent layer. The layers (always in odd number and at least three) can be connected by discrete joints, pins and nails, or glued together. This configuration enables to product large structural elements with considerable thickness. Two different experimental test campaigns were carried out on samples of panels with three and five glued layers. The purpose of
experimentation activities was to evaluate the bending deformation of the wooden
elements and shear strength of the bonding sections. All the tests were processed according
to the provisions contained in the UNI standards. The test results were then compared
with different theoretical calculation models to determine the one that best represents the
tested material.
The tests outcomes have shown that some characteristics of the material, such as
the remarkable ductility, open different scenarios of use for the CLT panels in the
field of structural restoration of masonry buildings.

The Bridge Over the Adda River in Brivio: History, Full-Scale Testing and FE Modelling

Scipedia content — Tue, 30 Nov 2021 14:51:30 +0100

Selected results from the investigation program of a historic R.C. bridge are presented in the paper. The bridge, crossing the Adda river between the Municipalities of Brivio and Cisano Bergamasco, consists of three tied arch spans, about 44.0 m length each, and represents a crucial node for the vehicular traffic of the region. After a maintenance intervention performed on one pier, the local Authorities committed to Politecnico di Milano an extensive investigation including: (i) documentary research and review of the bridge history; (ii) visual inspection and geometric survey of each span; (iii) full-scale load tests and ambient vibration tests; (iv) FE modelling of each span and validation of the numerical models (through comparison with the available experimental results) and (v) structural
assessment of the bridge in its present condition. After a concise review of the bridge history, the paper summarizes the complete results of the experimental tests performed on one span (visual inspection, geometric survey, full-scale load tests and dynamic tests) as well as the development of numerical models.

The Assessment and Reduction of Seismic Risk: Towards a System of Knowledge for Archaeological Pre-Existences

Scipedia content — Tue, 30 Nov 2021 14:51:22 +0100

The earthquake is a serious risk factor for archaeological heritage and, especially in this thematic area, the preventive protection assumes a strategic importance due to the lack of purpose that a reconstructive intervention would produce. However, the multiple problems of conservation and enhancement of the archeological heritage make the planning of damage mitigation complex, according to the criteria adopted for historical architecture. From the evolutionary framework of the sectoral regulations in Italy emerges a generic extension of the provisions for specific architectural monuments to the archaeological ones, in which the absence of connections or their intrinsic weakness, if any, increases their vulnerability.
Currently, it is clear that the absence of a specific "functional connotation" of ruins, apart from the visit one, places these contexts on the margin of the most recent regulations reconsiderations. Indeed, the current Linee Guida Mibact 2011 (Mibact Guidelines 2011) introduce a rapid evaluation methodology on a territorial scale (LV1) which does not consider the archaeological structures.
The paper proposes a rapid assessment method for the archaeological seismic vulnerability, which tries to connect the knowledge system with the analytical result on a territorial scale. This approach, based on a hierarchical system identification of structural 'morphos-types', is developed with applications conducted on the Roman Forum structures. Specifically, the attention is focused on the ruins constituted by walls without connections, whose structural behaviour, far from the global one, can be assimilated to a 'macro-element'. The seismic risk assessment is set according to the Carta del Rischio (the Risk Map) system methodology. This method introduces an algorithm for calculating structural vulnerability able to grasp the constructive and conservative specificities that influence the structural behaviour of the archaeological pre-existences.

The “Pieve di Santa Maria” in Arezzo (Italy). From the Laser Scanner Survey to the Knowledge of the Architectural Structure

Scipedia content — Tue, 30 Nov 2021 14:51:13 +0100

The parish church of “Santa Maria” is considered one of the most important medieval buildings of Arezzo Although the church is attested from 11th century, it is between the 13th and 14th centuries that reached its current consistency, characterized by the particular façade with small columns on several levels and an imposing bell tower. Later, from the 16th to the 18th century, the church underwent profound transformations, that were almost completely erased by extensive restoration works in the second half of the 19th century.
The architectural survey of the parish church of “Santa Maria” was carried out with a phase-shift laser scanner and a digital reflex camera (Z+F 5006h). 189 scans were performed for generating the 3D model of the church: 180 of them with high density and normal quality, lasting 5-6 minutes; the remaining ones with super high density and high quality, lasting 13-14 minutes. Vectorial drawings of plans and sections were then created from the 3D model.
Thanks to laser scanner survay of the chuch, it was possible to highlight the singularity of the structure of the basilical body and the transept. The tilt of walls and columns, the variations in the thickness of the walls, the considerable deformations of some arches, the cracks and textures of the wall facing were thus shown.
The information obtained attested an architectural structure created by complex construction events that over time have affected this building. The cnstructive singularities involve the medieval genesis of the building, the transformations during the following centuries and the following restoration works.
These composite features are specific and common to every ancient building. This peculiar epistemological condition eschews from simplifications and requires deep and complex studies closely linked to the problems of conservation of the structures.

Testing Calibration Issues in Resistance Drilling Applied to Timber Elements

Scipedia content — Tue, 30 Nov 2021 14:51:02 +0100

Resistance drilling devices are commonly used for the onsite inspection of wood and timber structural components in existing buildings. Although they provide a measure related to the density variation along a section of an element, results are used mainly qualitatively, due to several parameters that affect the computed values. In this paper, several new and old timber elements, taken from the dismantling of original roofs from a large existing historical building in northern Italy, are tested through a series of ND (non-destructive), SD (semi-destructive) and destructive testing procedures. Various wood species (spruce, fir, larch, oak, elm, pine) are taken into consideration. Among the applied testing methods (visual inspection, resistance drill, ultrasonic, needle penetration, radar, lab tests bending/compression), not all reported here, a focus on the resistance drill tests results is addressed, to evaluate the influence of consumption of the needle tip on the amplitude output. This was done by correlating the drillings to a reference sample on each test position to obtain data with an enhanced quantitative content. From the visual old timber elements grading, SD tests execution and successive element strength characterization through laboratory tests, it finally emerged the need for proper calibration of assessment methodologies through the application of a combined approach, in order to achieve more reliable results.

Studying a Masonry Sail Vault by Antonio da Sangallo the Elder in the Fortezza Vecchia in Livorno

Scipedia content — Tue, 30 Nov 2021 14:50:54 +0100

The present contribution aims to illustrate some first results obtained from ongoing research on a 16th-century masonry sail vault in the Fortezza Vecchia (the Old Fortress) in Livorno (Italy). A multidisciplinary research is currently ongoing. The information collected by means of geometric surveys and experimental tests are being used as input data for the different analytical and numerical models expressly developed to study the vault’s structural response. The structural analysis has been performed using two analytical models set within the framework of limit analysis. The first considers the vault as a thin shell, and suitable sets of statically admissible stresses are built; the second model is a modern reinterpretation of Durand-Claye’s method for domes. As an additional term of comparison, numerical analyses are carried out by means of FE models. The study is still
under development, and a first set of results has been obtained by limiting the analysis to vertical loads accounting for the self-weight of the vault and that of the overlying soil layers

Study on Strict Homogenization Method and Model of Masonry under Different Bricklaying Methods Based on Regular Tessellation Theory

Scipedia content — Tue, 30 Nov 2021 14:50:45 +0100

The brick and tile of the existing masonry structures are precious, so it is not feasible that the components are used as the dismantling unit for maintenance and reinforcement. The homogenization method is an ef ective multi-scale calculation method, which can be used to establish the analysis model of masonry on the mesoscopic-level. The plane tessellation deconstruction method of masonry structure is proposed, exploring the internal tessellation laws of masonry under dif erent bricklaying methods, and the theoretical system of periodic plane segmentation of masonry is established. Based on regular tessellation theory, the plane segmentation of masonry structures under three kinds of bricklaying methods is periodically carried out through rectangular unit lattice. Deconstructing the smallest element of the tessellation form, the boundary condition of equivalent volume element (RVE) is derived. On the premise of selecting reasonable material parameters, RVE models under three kinds of bricklaying methods are built by finite element software ABAQUS, and the equivalent parameters are obtained to realize the simulation analysis of masonry structure based on micro-mechanics. The results show that the strength of running bonding RVE is higher than that of the other two kinds, and the strength of header bonding RVE is the lowest. The finite element results are compared with the compressive strength results of the specimens under three kinds of bricklaying methods in the existing tests. The results are in good agreement, which shows that the compressive capacity of masonry structures with homogenization simulation under three kinds of bricklaying methods is reliable while homogenization reflects the mechanical characteristics of masonry structure as a whole. The rigid homogenization method based on regular tessellation theory takes brick by brick as components to be dismantled and replaced in the ancient architecture, which opens a new way for the fine analysis of masonry structure. The rigid homogenization method maximizes the protection of the ancient masonry structure, which is of great significance for the protection of human cultural heritage.

Study on Seismic Performance Evaluation of Modern Wooden School Buildings in Japan

Scipedia content — Tue, 30 Nov 2021 14:50:38 +0100

Japanese school buildings have been changed from modern wooden structures to reinforced concrete structures after the Building Standard Law was established in 1950. Therefore, only a few modern wooden school buildings exist currently. Ensuring the seismic resilience of these wooden school buildings is essential for their preservation and longevity. In this study, a static pushover analysis was conducted for a modern wooden school building using a 3D frame model to simulate the relationship between lateral load and deformation. This 3D frame model was proposed based on the site investigation and the 2D frame model used in a previous study. From the analysis results, it is found that the bearing capacity was decided by the deformation capacity of the column-to-groundsill connection; therefore, reinforcement to these connections was required to improve the seismic performance of a modern wooden school building

Study on Causative Agents of Damage in the Costa Rican Caribbean Architecture from a Multidisciplinary Perspective

Scipedia content — Tue, 30 Nov 2021 14:50:25 +0100

The aim of this communication is to analyze the architectural, historic and construction values of the Costa Rican Caribbean architecture, which constitutes an architectural typology of the identity of the city of Limón. Damages linked to biological agents in these buildings were identified based on the multidisciplinary research project titled “Conservation of the Costa Rican Caribbean architecture by applying advanced techniques for studying the causative agents of damage in the buildings”.
An inventory of the study area was conducted in order to identify predominant elements of this type of architecture, as well as to quantify and georeference, through a Geographic Information System, the buildings that are still preserved; the identification of damage-causing agents within the inventory was also part of the process. As a second stage, samples taken from the buildings will be analyzed in the biological sciences laboratory to identify biological agents that were potentially responsible for damage.
Thirty representative buildings of the Costa Rican Caribbean architecture were identified, for which inventory records were made that included information about architectural and building aspects, as well as damage identification and classification, and types of causative agents. Based on a multi-criteria evaluation, Capitanía de Puerto, Casa Misionera de la Iglesia Bautista and other edifications were selected as the buildings to conduct the inventory of biological damage, sampling, and environmental monitoring.

Structural Typificaton of Heritage Builings Using Modern Technologies for Digital Management and Visualization: Preliminary Applications in Southern Peru

Scipedia content — Tue, 30 Nov 2021 14:50:15 +0100

Structural typologies represent a group of buildings with similar geometrical configuration and seismic performance. These typologies are normally used in the preliminary stages of structural assessment of building stocks since they provide an overview of quick results which guide subsequent studies of cases that resemble the types. This article provides a methodology of structural typification using modern technologies for digitalization and visualization of information based on the study of a representative sample of 22 churches located in the South Andean zone of Peru and considered as part of Peru’s Cultural Heritage. For each church, the information has been acquired and digitally modeled through the integration of reverse engineering methods and Heritage Building Information Modelling (HBIM). Furthermore, in order to improve the visualization and interaction experience, a mobile application using Augmented Reality was developed. The use of these modern techniques allowed the management of the information, which enhanced the comprehension of the churches and thus enabled its further structural analyses. As a result, it has been identified 11 structural typologies of Andean churches, based on the material of its load bearing system, their architectural form and some geometrical particularities of its structural elements.

Structural Restoration and Re-Use of the Historic Coal Mine Tower

Scipedia content — Tue, 30 Nov 2021 14:50:05 +0100

The coal mine is located in the town of Labin, Istria peninsula, Croatia. Restoration of the tower is a part of the project that includes thorough restoration and re-use of the Labin mining complex for cultural, tourist and educational purposes. The tower was built in 1938 by Italian authorities as part of the pre-war campaign. It is a 32.5 m high steel structure that once enveloped the elevator to a 200 m deep mine shaft. The structure is a built up Vierendeel truss with four columns / chords connected with horizontal moment resistant beams. Two large steel inclined struts were resisting elevator rope forces connected to the elevator machine building. The mine was shut down in 1988. The assessment of the tower consisted of geometry measurement, cross-section shape determination, steel quality determination, condition of members and connections (rivets and bolts), protective coating condition and underground supports condition. Two samples were taken to laboratory to determine the steel grade with tensile yield test. Structural model with existing members has also been analysed. Different loads were considered comparing the original purpose of the tower and the planned representational purpose. In addition, structural member verification according to Eurocode
standards has been done. Load bearing steel structure is geometrically sound, mostly with no visible deformations, deflections or drifts. Foundations are crack free and with no visible subsiding. Lack of maintenance of the anticorrosive coating from 1988 until today caused most of the damage. Due to the significantly aggressive environment, anchoring part of the structure was severely ruined. Lower part of the above ground structure was in the similar condition. Water retention and salt carried from the lower part of the shaft caused significant damage to the steel structure in these areas. Replaced members were built in with original riveting technique. Anchoring structure replacement called for a temporary support structure, which represented the most demanding operation in the whole restoration process. The temporary support structure was a steel truss structure in pyramidal form that allowed complete removal of the lowest segment and reconstruction of the anchoring elements and concrete foundation. According to the evaluation, existing galleries that surrounded the tower had to be completely removed and redesigned with new loads. Future use of the tower with its galleries is primarily of representational purpose. Moreover, a new elevator with its own structure inside the existing tower is considered and it has no influence on the existing structure. Since the tower is registered as an architectural heritage by the Croatian Ministry of Culture, specific demands regarding structural restoration were issued. The principles of structural analysis and restoration together with multidisciplinary approach have been applied in this project.

Structural Performance Evaluation of Column-Nuki Connection in Traditional Japanese Wooden Buildings

Scipedia content — Tue, 30 Nov 2021 14:49:57 +0100

Traditional Japanese wooden buildings have been constructed using internal wooden frame structures. Plus-shaped column-nuki connections are important to evaluate the seismic performance of these buildings, and these connections include several joint types, one of which is the oblique scarf joint. However, only very few extant studies have examined column-nuki connections and oblique scarf joints. Consequently, no design equations exist for this combination. Therefore, it is possible that the structural performance of column-nuki connections might be inaccurately evaluated. Thus, this study aims to evaluate the structural performance evaluation of column-nuki connections in traditional Japanese wooden buildings. Full-scale tests were performed on specimens with either the continuous or oblique scarf joint nuki, and results obtained were compared based on parameters, such as the type of connection and number of dimensions. Subsequently, corresponding analytical results were calculated using an extant design equation, and the same were compared against experimental values to determine the validity of using the design equation for column-nuki connections in traditional Japanese wooden buildings. Results obtained in this study demonstrate the initial stiffness to be approximately identical for specimens with continuous or oblique scarf joint nuki. The yield and ultimate bending moment of oblique scarf joint nuki specimens were observed to be approximately 10–70% smaller compared to those corresponding to continuous nuki specimens.
In addition, all oblique scarf joint nuki specimens demonstrated an initial cleavage failure followed by multiple failures. Results of these comparisons demonstrate that failure can be partially estimated using the extant design equation considered in this study.

Structural Performance and Durability Issues of Vernacular Schist Masonry

Scipedia content — Tue, 30 Nov 2021 14:49:50 +0100

Stone masonry is recognized as one of the most used vernacular construction techniques around the world. Although centuries of proven resilience and high adaptability to context, stone masonry has been progressively replaced in construction industry in the last decades, namely in countries as Portugal, by industrial and concrete-based materials and building systems. Nowadays, with the lack of traditional masons, an important part of traditional stone masonry constructive know-how is endangered. In face of growing concerns regarding heritage preservation, researchers are aware of the need to scientifically know such structures. Being less studied, vernacular schist rubble masonry was selected as case study and tested to characterize its mechanical behaviour and durability parameters. The potential of retrofitting of such structures was also assessed [1].
Eighteen double-leave wallets were built following local building traditions [2] and prepared according to 3 different setups of 6 specimens each: i) non-coated; ii) coated with commercial lime coating; iii) coated with commercial lime coating and injected with lime-based grout. The experimental campaign was designed and implemented in stages for a period of three years: i) experimental characterization of stones and mortars; ii) axial compression testing of reference specimens; iii) salt-based accelerated aging following wet-dry procedures [3]; iv) axial compression testing. Damage progression was monitored by visual inspection, mass variation and sonic testing [4].

Structural Monitoring in the “Santa Maria de la Asunción” Cathedral of Chilpancingo, Guerrero, Mexico; through Topogeodesic-Photogrammetric Surveying and Ambient Vibration. A Methodological Proposal

Scipedia content — Tue, 30 Nov 2021 14:49:41 +0100

This paper presents a review of the state of the art of structural health monitoring using three inspection techniques and their application in the proposed methodology for the study of a historic structure located in a high seismic hazard area. The proposed approaches are a) use of an unmanned aerial vehicle (UAV), a reliable platform for data acquisition in photogrammetric inspection and surveillance work due to its simple handling and accessibility to human risk zones; b) Global Positioning System (GPS), which offers the capability of static or dynamic monitoring, using kinetic navigation (RTK), precise point positioning (PPP) or combination of both methods; c) ambient vibration (AV), an accelerometer test that determines the dynamic properties of a structure, of which values indicate the structural safety status. The building to be studied is the “Santa María de la Asunción” Cathedral of Chilpancingo in Mexico, which represents a great historical value because it hosted the First “Anahuac” Congress in 1813. The structure covers an area of 1056 sqm and has a height of 33.31 m. The construction began after 1902 and has been affected by several seismic events. Because of the earthquake of December 2011, cracks occurred in the basements and keystones of the arches of the two bell towers, severe damage to the right tower, and moderate to the left one. In the frontispiece, top of the arches, and in front of the central nave vault also appeared cracks. The reinforcement process is currently complete. The expected results are a matrix of distances among control points in the building, high-resolution ortho-images, and values of the dynamic structural properties. According to the architectural and structural characteristics, location, importance, and use of the structure, it is proposed to perform a monitoring every six months or after an earthquake with a seismic magnitude greater than six and epicenter less than 60 km. The comparison of the measurement parameters will indicate the structural health of the building.

Structural Modelling and Numerical Analysis of the Palace of Sports of Mexico City

Scipedia content — Tue, 30 Nov 2021 14:49:31 +0100

The palace of sports represents in many ways the masterpiece from the urbanarchitectural legacy that was created for the XIX Olympiad in Mexico City in 1968; its uniqueness, from the architectural and structural point of view, makes it one of the most iconic buildings of the city. In this paper the structural modelling and numerical analysis of this iconic building of the Mexican architecture of the second part of the XX century is presented. The numerical modelling is achieved by means of a 3D finite element model in order to obtain preliminary results in terms of dynamic properties and linear and non-linear response of structural elements when subjected to gravity loads. Natural periods of the modes with high participating mass obtained on the numerical model are in well agreement to those of other structures with similar configurations. Nonlinear results show that the structure has a large safety factor under gravitational loads. Finally, recommendations about the improvements that can be applied on the actual FEM model are given based on the results obtained in order to give a better assessment to identify risk scenarios and to prevent them tooccur on such iconic structure.

Structural Health Monitoring of the Juma Mosque in Itchan Kala in Khiva (Uzbekistan): Laser Scanning Combined with Numerical Modelling

Scipedia content — Tue, 30 Nov 2021 14:49:23 +0100

This paper highlights the main objectives and some of the results of an extensive structural health monitoring (SHM) project begun in Khiva, Uzbekistan. The research team consists of experts from the University of California, Berkeley (Berkeley, USA) and Urgench State University (Urgench, Uzbekistan). According to archaeological data, the city of Khiva was established approximately 1500 years ago. The project started from Itchan Kala, the walled inner town of the city of Khiva. This paper describes results obtained for the Juma Mosque located inside of Itchan Kala. A continuous SHM became essential to ensure its preservation for humanity because a few structural anomalies were reported in the past. The ongoing project consists of three major phases. First, a terrestrial laser scanning (TLS) was deployed to capture and monitor anomalies of the monument’s geometry in 3D. A laser scanner was used, and the monument’s geometry was captured as a collection of points, which is called a “point cloud”. Second, there is a plan to monitor the monument by in-situ measurements conducted by accelerometers, position transducers and thermocouples in the next phase. The high-sensitivity accelerometers will be used to study the resonant frequencies due to the
ambient vibrations. The position transducers and thermocouples will be used for measuring the thermal expansion and retraction of the monument’s minaret. They will also be used for monitoring the crack openings. Third, a finite-element (FE) model based on the as-found geometry of the point cloud will be generated. Its calibration will be based on the collected data to ensure acceptable correlations with the results of the conventional measurements. The FE model will be used for future restoration efforts to evaluate the performance and efficiency (if any) of the proposed restoration measures. This paper focuses on the results obtained for the Juma Mosque’s minaret. It discusses the major findings of the laser scanning project and estimates the minaret’s residual inclination and its taper. The paper shows that the minaret can be approximated by a truncated cone. A preliminary FE model of the minaret was developed, which will be updated based on the results of the upcoming ambient vibration study.

Structural Health Monitoring of a Historic Church: Theory and Practice of Diagnostic Approaches Used to Control Risks and Costs

Scipedia content — Tue, 30 Nov 2021 14:49:15 +0100

Structural Health Monitoring is an exciting opportunity to use real time quantitative data of a structure’s response in analysis and evaluation. However, this technology has yet to achieve common use in practice and remains linked to research of iconic buildings. This paper discusses the challenges and opportunities for use of SHM for widespread projects with damaged buildings and limited budgets. The SHM approach used was long term low frequency (static) data collection of both environmental inputs and structural responses. This data was used to develop relationships between loads and responses that could be effectively used to determine safety of the building and where in the structure deterioration continues.

Structural Evaluation of Typical Historical Masonry Vaults of Cagliari: Sensitivity to Bricks Arrangements

Scipedia content — Tue, 30 Nov 2021 14:49:06 +0100

Masonry vaults have a great diffusion in the historical architectural heritage: in this work, their structural behavior is investigated. Attention is focused on lowered sail vaults composed by several brick arrangements, a typical nineteenth-century masonry vault which have great diffusion in Cagliari (Sardinia). The target is evaluating the role played by bricks arrangement in their mechanical behavior. A series of rigorous laser scanner surveys have been performed in order to obtain the effective geometry both at macro-level – the vault shape – and at micro-level – brick patterns. A NURBS (Non-Uniform Rational B Spline) representation of the geometry is adopted and adaptive upper bound limit analyses are performed. NURBS entities, which are common in commercial CAD packages, have the great advantage to describe complex geometries such as curved elements, with very few elements. An upper bound limit analysis formulation is adopted, in which the NURBS elements forming the mesh are idealized as rigid bodies with dissipation allowed only along interfaces. The mesh constituted by few NURBS elements is progressively adjusted through a genetic algorithm in order to minimize the live load multiplier. Limit analysis is performed initially to determine the collapse multiplier of vertical loads, to assess the load bearing capacity of the vault, then attention is focused on differential settlements, that may be a serious hazard for this structural typology.

Structural Evaluation of the Greenhill Mine Tipple Structure Historic Site

Scipedia content — Tue, 30 Nov 2021 14:48:57 +0100

The tipple building located within the Greenhill Mine complex (a Provincial historic site) in southern Alberta, Canada is a reinforced concrete frame with a steel superstructure. The structure has been analyzed to assess its current state and the extent and causes of deterioration. The analysis is performed using data obtained from field and laboratory tests and evaluations and by using SAP2000 structural analysis software. Possible ways for conservation and restoration of the building for two different future uses are explored, and recommendations are provided.

Structural Evaluation and Maintenance of Brooks Aqueduct Historic Site

Scipedia content — Tue, 30 Nov 2021 14:48:50 +0100

Brooks Aqueduct in Alberta, Canada is one of the largest and most sophisticated reinforced concrete aqueducts in the world. Now a national historic site, Brooks Aqueduct was built in 1914. The structure suffers from cracking and degradation in certain locations. To find out the possible main causes of potential overstress and damage in the different areas of the structure, it was evaluated by site inspections, some laboratory tests and analyzed numerically using Abaqus finite element software. Results of the numerical analysis are compared with the inspection and testing results and conclusions are made about the causes of deterioration and ways to conserve and repair the structure.

Structural Assessment of the Seismic Behavior of the Dome of the Taj Mahal

Scipedia content — Tue, 30 Nov 2021 14:48:40 +0100

This paper presents the results of a study of the structural assessment of the seismic behavior of the main dome of the Taj Mahal, in Agra, India. Built by the Moghul emperor Shah Jahan between 1632 – 1648 AD, the structure is one of most famous buildings in the world and the finest and most sophisticated symbol of Moghul architecture in India. As it is located in a zone of moderate seismicity, there is an urgent need for ensuring the structural safety and preservation of this iconic cultural heritage for future generations. The objective of this study is to develop a simplified approach to enhance our conceptual understanding of the mechanism of load path/transfer in the dome of the Taj Mahal under both gravity and seismic loads, as well as to better understand the influence of the geometry of the dome on its structural behavior. Using the software SAP2000, a finite element model of the dome is created and analyzed under the action of gravity and seismic loads, with the seismic loading assumed to have a PGA of 0.25g based on the results of a study conducted by the Indian National Disaster Management Authority. The results obtained include plots of the distribution of nodal reactions at selected levels to represent the lateral load behavior of the dome of the Taj, as well as plots illustrating the paths of load transfer under the action of gravity and seismic loads. Free body diagrams of selected rings are also presented to illustrate the ‘hoop’ forces in the dome, while simplified internal stresses are computed and compared with known material properties. Observations are also presented about the effect of the dome geometry, especially the bulging part of the dome, on the distribution of reactions and the resulting mechanism of load transfer in the structure under both gravity and seismic loading.

Structural Assessment of the 13th Century Great Mosque and Hospital of Divrigi: A World Heritage Listed Structure

Scipedia content — Tue, 30 Nov 2021 14:48:30 +0100

The Great Mosque and Hospital of Divrigi is located in the central eastern part of Turkey, in Divrigi, Sivas. The historical facility consists of a monumental mosque and a two-story hospital, which are adjacent to each other. The structure dates back to 13th century Mengujekids period and has been listed by the UNESCO as a World Heritage since 1985. Great Mosque and Hospital of Divrigi is particularly notable for its monumental stone portals that are decorated with three-dimensional ornaments carved from stone. The structural system of the monument consists of multi-leaf stone masonry walls and stone piers that support the roof structure which consists of stone and brick arches and vaults. The structure is located about 90 km away from the North Anatolian Fault Line, that has been causing several destructive earthquakes. Consequently, the structure is prone to destructive seismic activities. In this study, after a brief introduction on the structural system and current condition of the structure, the structural performance of the Great Mosque and Hospital of Divrigi is investigated through site observations and structural analyses. For this purpose, linear and nonlinear 3D finite element models of the structure are developed and the structure is examined under the effects of vertical loads and seismic actions. In the light of the analyses results, recommendations for potential interventions are outlined for further preservation of the structure.

Structural Assessment of Cultural Heritage Buildings Using HBIM and Vibration-Based System Identification

Scipedia content — Tue, 30 Nov 2021 14:48:18 +0100

The paper exemplifies the application of the methodology involving historic and
architectural research complemented by HBIM and operational modal testing in the structural
modelling of a heritage palace, the Galleria degli Antichi in the historic town of Sabbioneta (Italy),
included in the UNESCO World Heritage list since 2008. This monumental building was built in the
16th century. Full details on the history of the building and the information obtained in the non destructive survey are given in the paper. The good knowledge of the structural geometry, along with
the complete inspection carried out and the large number of identified vibration modes, allowed to
establish a numerical model of the monumental building for a first quantitative assessment of its
structural condition.

Structural Analysis of Historical Constructions by Graphic Methodologies based on Funicular and Projective Geometry

Scipedia content — Tue, 30 Nov 2021 14:48:07 +0100

This paper presents a graphic methodology for the structural analysis of domes and other surfaces of revolution, based on a combined use of funicular and projective geometry. By considering a dome as a network of lines of latitude and longitude, the equilibrium of the network is analyzed in both horizontal and vertical projection. The resulting dual configuration is also a spatial system that can be considered by its projection in a horizontal and a vertical plane.
The dome is divided by latitude and longitude into an arbitrary number of sectors, and the equilibrium is enforced at each node. The tangential forces can be considered for their net effect at each node; the net effect of two tangential forces, equal in magnitude, at a node is a radially directed force in the plane of the line of latitude, acting outwards (compression) or inwards (tension).
Considering their horizontal projection, and its dual form, it is possible to choose the shape of the radial force diagram (the vertical projection and the force diagram), and identify the radial forces associated with it, and thus the tangential forces. The new methodology is presented through its application to a hemispherical brick dome of small thickness.
The hemispherical brick dome has been also analyzed by applying the slicing technique, considering different hypotheses regarding the structural behavior of the haunch filling, according to its morphological characterization.
The structural analysis of the brick dome using both methodologies allows us to contrast the results obtained.

Structural Analysis as a Supporting Method for the Research of Medieval Brick Architecture

Scipedia content — Tue, 30 Nov 2021 14:47:56 +0100

Chronology of brick historical buildings might be established much more precisely than the chronology of stone ones due to the architectural and metrical analysis of bricks, mortars and brickworks. Comparison of historical sources allows to reconstruct the previous stages of constructing monuments. Causations between transformations and developments of monuments are usually interpreted as the results of artistic or ideological influence rather than pragmatic decisions. Such explanations neglect, however, the impact of structural disasters and imperfections. Experience, delivered by the previous erroneous solutions or failures, undoubtedly influenced the further development of architecture. In this paper the authors present how numerical modelling and structural analysis of complex historical brick buildings and different stages of their alterations might be used as a supporting method for the research of their history. Consequently, modern numerical tools for structural analysis can also be useful in investigating of the process of creating architectural
solutions [1]. Because more accurate historical analyses belong to the qualitative research, it is not possible to examine very wide group of different monuments. Therefore the authors chose for that purpose the homogeneous group of the mendicant orders’ medieval churches in the former State of Teutonic Order in Prussia, which have been the subject of authors’ in situ research since 2009 [2]. This group is thought to be representative for the medieval techniques of the brick architecture in northern Europe and Baltic Sea Region. The aim of this research is to find out whether structural analysis might be carried out in a historical building in which consecutive transformations partially erased its original form (reconstructed on the base of the architectural and archaeological research)? A positive answer to that question allows to put another one – about whether the numerical modelling of the structure of monument might give some additional information on its history? The results of described research might give a new tool for conservators, architects, archaeologists and
engineers in their research and other conducting works.

Stochastic Micro-Modelling of Historic Masonry

Scipedia content — Tue, 30 Nov 2021 14:47:48 +0100

The non-linear analysis of historic masonry structures can be difficult to perform due to the highly irregular geometric features, the inherent variability within the materials, as well as the limited amount of experimental data available. The present work details a specific methodology and result for the analysis of the compressive strength of the masonry found in walls of St. Ann’s Church in the Czech Republic. A multi-scale 2D finite element modelling approach was adopted. In a mesoscale-level representation of masonry, “small stones” were grouped in with the mortar and treated as a matrix component with homogenized properties, while large stones were treated as discrete inhomogeneities. To characterize this matrix component, microscale-level models were used, in which only the “small stones” and mortar were represented. By simulating uniaxial compression and tension tests on multiple microscalelevel models, statistical distributions for compressive and tensile strength, stiffness, and fracture energy were determined. On the mesoscale-level, overall stiffness and compressive strength were determined by simulating uniaxial compression tests on models involving only the large stones embedded in the homogenized matrix. The matrix was considered either as spatially uniform or variable. In the latter case, it was modeled with random fields based on
the properties’ distributions obtained from the micro-scale model analyses. Furthermore, the multi-scale study was performed for two different threshold sizes defining the “small stones” to compare differences. Approximate qualitative methods were utilized to validate the results. Overall, decreasing compressive strength was observed from the plain mortar to the microscale model of mortar with “small stones” to the meso-scale model of masonry. Models where matrix variability was represented with random fields exhibited similar failure mechanisms but with strengths 5-6% lower than models with a uniform matrix. Therefore, the effect of the spatial variability of the matrix properties was deemed insignificant.

Stiffness Changes due to Static Loading of a Brick Arch

Scipedia content — Tue, 30 Nov 2021 14:47:40 +0100

A brick arch was loaded under laboratory conditions in three successive loading steps. No cracks were observed but reduction of natural frequencies and stiffness of the arch was experimentally documented. The stiffness was evaluated in a non-destructive test using an impact hammer and only two accelerometers. The proposed identification technique based on known experimental modal analysis theory is tailored to stiffness evaluation of masonry vaults. The results and the applied method are extensively discussed.

Static Test on Full Scale Rammed Earth Building with Mesh-Wrap Retrofitting Strategy

Scipedia content — Tue, 30 Nov 2021 14:47:28 +0100

This paper reports the experimental campaign for static tests performed on unreinforced (URE) and mesh retrofitted (RRE) full scale rammed earth building. Amongst varying building patterns of traditional rammed earth houses found in Bhutan, a two-storied building with a full solid wall (small openings) on the first floor and larger opening in the front facade of the second floor was chosen. The proposed mesh–wrap retrofitting of the walls involved the use of standard mild steel welded mesh as the main mesh, M–Mesh (Ø 1.8 mm and 34 mm c/c spacing) and light and galvanized welded mesh as a lapping mesh, L–Mesh (Ø 1.45 mm and 28 mm c/c spacing) provided at the corners and along the height of the walls. The static test loading protocol involved the displacement controlled loading with drift-control over the building. Cracks and damage observations were made at the storey drift ratios of: 1/2000, 1/1000, 1/750, 1/500 for URE building. The same URE building was retrofitted afterward and retested as RRE to storey drift ratios of: 1/2000, 1/1000, 1/750, 1/500, 1/250, 1/150, 1/100 and 1/75. The mesh retrofitting is found effective in both damage control as well as strength
enhancement over the unreinforced one. The URE specimen showed a clear opening of shear and vertical cracks in the in-plane loaded walls near the openings and Jugshing holes. For the RRE specimen, cracks dispersed over a large region of the in–plane loaded walls. No delamination of mesh–wrap was observed, showing the effectiveness of the proposed technique. The RRE specimen showed enhancement in base shear by 2.5 times, ductility 2.3 times, and energy absorption 12 times the URE counterpart.

Static and Dynamic Load Test of Libeň Bridge Over Vltava River in Prague and Concept of Repair

Scipedia content — Tue, 30 Nov 2021 14:47:20 +0100

The Libeň bridge in Prague is a cultural and technical heritage of concrete construction of the beginning from the twentieth century. The bridge was designed by architect Pavel Janák, the founder of cubism in architecture. According to experts, the Libeň bridge is the only example of cubist morphology application on the bridge structure. Evaluation of Libeň bridge structural condition is an up-to-date topic leading to decision whether this bridge should be repaired or replaced by a new bridge. This article deals with the static and dynamic load testing in comparison with following creation and validation of the FEA model for load carrying capacity assessment of the Libeň Bridge and possible way of reconstruction. Paper deals with crucial procedures for FEA model validation of this backfilled arched concrete structure with a focus on the static characteristic of the structure. Article deals with reconstruction of the vault part of the Libeň Bridge using R-UHPFRC in terms of static operation. It focuses on the two basic problems of the bridge, the solution to increase the bearing capacity of the vault arches and to increase the bearing capacity of the foundations under pillars. The concept of repair is based on extensive diagnostic surveys conducted in 2017. The concept of structural enhancement is based on adding new thin layer of R-UHPFRC (reinforced, ultra-high performance concrete) on the upper vault surface. Concrete bridge structures are exposed to extreme effects of aggressive environmental influences, especially chlorides, which leads to damaging of most exposed bridge components a long time before their service life. UHPFRC material is suitable for repairs of these structures and especially due to its impermeability and high resistance.

Static Analysis of a Masonry Arched and Buttressed Retaining Wall

Scipedia content — Tue, 30 Nov 2021 14:47:12 +0100

The wall of Casa Salvans is a masonry arched and buttressed retaining wall which was built in 1909 and located in Terrassa, Catalonia. It contains a series of 11 arches of unique shapes, dimensions and inclinations that are supported on buttresses. Despite being a common retaining wall typology, it can be very challenging to assess the stability of such structures given the variability of their geometry. As such, a systematic methodology for the stability assessment of such walls was developed and applied to the case of the wall of Casa Salvans. Self-produced photogrammetry survey enabled creating accurate three-dimensional models of the front of the wall that were later combined with available information from a topographic survey to build cross sections of the wall for analysis. Modern retaining wall design principles evaluating the stability against overturning and sliding were used to assess the condition of the wall. As a consequence of the uncertainties related to the soil parameters and buried elements of the wall, the stability factors could not comply with modern design criterion. Some parametric analyses were carried out on the shear strength parameters of the backfill, revealing that slight increases in the soil internal friction and wall friction angles enhance the stability factors significantly. Since reasonable soil internal and wall friction angles justifying the stability of the wall were obtained, carrying out a geotechnical survey to determine the actual values was recommended. The in-plane stability of the arches was also verified according to the Lower Bound Theorem by locating a thrust line that fits within all the boundaries despite very conservative geometric assumptions.

Standard Gravity and Wind Load Analysis on 103-years old Unreinforced Masonry Building

Scipedia content — Tue, 30 Nov 2021 14:47:05 +0100

Finite element modelling and analysis has been performed on 103-years old unreinforced masonry Senate hall building (SHB), Allahabad University, India. It is an Indo-Saracenic style of architecture which was built in 1915. An in-situ survey is conducted to know the present condition of the SHB. The major and minor cracks are visible, and construction material has deteriorated at various part of the SHB. The old documents, reports, on-site measurement, and photographs are used to gather the historical data and prepared the accurate model of the SHB on Ansys workbench (ANSYS 14.0) tool. Macro and homogenisation approach has used in the modelling of the SHB. The standard gravity and wind load analysis is performed with a fixed boundary condition on its based of SHB. In gravity analysis, maximum stress (5.69MPa) has been observed at the connections of the ground floor and maximum deformation (7.8mm) on the crown of the arch of the first-floor. The maximum stress and deformation 14.286MPa and 12.491mm have been observed under live load analysis. Further, the maximum stress and deformation obtained under wind load analysis are 4.10MPa and 8.07mm, respectively. The finite element simulation and visual inspection of the SHB are in good agreement with the present condition of the structure.

Stabilization and Consolidation of Historical Multi-Leaf Masonry

Scipedia content — Tue, 30 Nov 2021 14:46:56 +0100

Historical masonry structures with a greater thickness can often be made as so called multi-leaf masonry with outer leaves lined with the application of some of the masonry bonding methods and with the inner leave of the so-called cast core formed by fragments of stones of different sizes that are bonded with more mortar. The load capacity, stiffness and the failure mechanism of multi-leaf masonry are influenced by the interaction of individual leaves with different deformation and physico-mechanical properties and the nature of the mutual connection of individual leaves of masonry. The performed analyses showed a significant influence of especially the cast core masonry tensile strength and the contact joint strength between the core masonry and the outer leaves.

Soil Settlement and Uplift Damage to Architectural Heritage Structures in Belgium: Country-Scale Results from an InSAR-Based Analysis

Scipedia content — Tue, 30 Nov 2021 14:46:46 +0100

Soil movement may be induced by a wide variety of natural and anthropogenic causes, which are detectable in the local scale, but may influence the movement of the soil over vast geographical expanses. Space borne interferometric synthetic aperture radar (InSAR) measurements of ground movement provide a method for the remote sensing of soil settlement and uplift over wide geographic areas. Based on this settlement and uplift evaluation, the assessment of the potential damage to architectural heritage structures is possible. In this paper an interdisciplinary monitoring and analysis method is presented that processes satellite, cadastral, patrimonial and building geometry data, used for the calculation of settlement and uplift damage to architectural heritage structures in Belgium. It uses processed InSAR data for the determination of the soil movement profile around each case study, of which the typology is determined from patrimonial information databases and the geometry is calculated from digital elevation models. The impact on the historic structures is calculated from the determined soil movement profile based on various soilstructure interaction models for buildings. The resulting damage is presented in terms of a numerical index illustrating its severity according to different criteria. In this way the potential soil movement damage is quantified in a large number of buildings in an easily interpretable and user-friendly fashion. The processing of InSAR data collected over the previous 3 decades allows the determination of the progress of settlement- and uplift-induced damage in this time period. With the integration of newly acquired and more accurate data, the methodology will continue to produce results in the coming years, both for the evaluation of soil settlement and uplift in Belgium as for introducing related damage risk data for existing architectural heritage buildings. Results of the analysis chain are presented in terms of potential current damage for selected areas and buildings.

Slow-Moving Landslide Damage Assessment of Historic Masonry Churches: Some Case-Studies in Italy

Scipedia content — Tue, 30 Nov 2021 14:46:37 +0100

This paper presents a contribution for the damage assessment of historic masonry churches exposed to slow-moving landslides. In particular, the authors identified four global damage mechanisms, which are presented here by means of the critical damage assessment of four case studies located in the Liguria region (Italy) in areas affected by slow-moving landslides. For each church, a correlation between the damage patterns observed on-site and the ground movements induced by landslide phenomena was sought by means of visual inspections and crack interpretation. As a result, each damage mechanism was associated to a different pattern of ground movements produced by slow-moving landslides.

Simulation of the Out-of-Plane Behaviour of URM Walls by Means of Discrete Macro-Element Method

Scipedia content — Tue, 30 Nov 2021 14:46:27 +0100

The seismic response of masonry structures without box-type behaviour is given by a complex interaction between in-plane and out-of-plane behaviours. Previous earthquakes demonstrated that out-of-plane failure mechanisms represent the main cause of structural collapses of UnReinforced Masonry (URM) and historical structures. Previous experimental and analytical studies, investigating the out-of-plane behaviour of URM structures, mostly considered the effects of one-way bending moment. In this regard, recent experimental campaigns and numerical simulations have been conducted in order to investigate the out-ofplane behaviour of masonry walls subjected to two-way bending. These investigations have demonstrated the complexity of this mechanism and stressed the need for accurate numerical tools capable of providing reliable predictions in terms of ultimate strength and failure mechanisms. This paper focuses on the assessment of the dynamic behaviour of a U-shape URM prototype, subjected to shaking table tests, by means of a simplified computational strategy denoted as Discrete Macro-Element Method (DMEM). In this investigation, a comparison
between experimental and numerical results was conducted in order to validate the capabilities of the proposed modelling approach. Subsequently, a parametric analysis was carried aiming at determining the influence that masonry mechanical properties, and additional model parameters, have on the out-of-plane nonlinear dynamic response of URM masonry structures.

Simplified Seismic Vulnerability Assessment of Medieval Masonry Churches

Scipedia content — Tue, 30 Nov 2021 14:46:17 +0100

The meaningful seismic events occurred in Italy in the last decades showed the high vulnerability of monumental buildings and in particular of churches. In order to preserve such a precious heritage, operations aimed at the seismic risk mitigation based on the definition of suitable vulnerability assessment procedure are necessary. The high hazard of the Italian Peninsula and the huge amount of ecclesiastic buildings located in the exposed territories, stress the need to face the problem with innovative large-scale approaches. In this study, an architectural-engineering integrated procedure for the seismic assessment of existing masonry churches at a regional scale is proposed. Based on accurate historical investigation of typical Abruzzi churches, a typological characterization has been established, aimed at recognizing the common geometrical and constructive features of two types of
medieval churches widespread in this area. Then, a numerical analysis has been carried out. In particular, by assuming simplified modelling hypotheses, two FE models representative of significant real cases have been implemented in Abaqus. By the elastic analyses, the main collapse mechanisms and the corresponding activation seismic accelerations have been determined. The obtained outcomes show an acceptable correspondence with the actual seismic damage revealed on similar churches in the aftermath of last seismic events, corroborating the reliability of the adopted integrated approach.

Simplified Method for the Lateral Strengthening of Adobe Walls in Andean Churches

Scipedia content — Tue, 30 Nov 2021 14:46:09 +0100

The evaluation of the seismic safety of Andean colonial churches is of high importance as those buildings represent part of the identity of the society and are historical emblems for the communities. Most of these buildings are composed of elongated naves with adobe masonry walls with flexible (or nonexistent) horizontal diaphragms, which generates potential of out-of-plane failures. In the last decades, different methodologies using advanced numerical analyses have been developed that allow evaluating the structural behavior of historical constructions at the expense of an arduous computational effort. In the present paper, a simplified tool is proposed for the design of walls lateral reinforcement using buttresses. The tool uses limit analysis and provides an adequate buttress design according to the configuration of the wall and seismicity of the area where the church is located. The results of the application of the methodology showed that the developed tool provides fast and accurate alternatives for the seismic strengthening of Andean adobe churches. The use of buttresses as structural reinforcement control the development of out-of-plane failure mechanisms, and provide lateral stability and resistance to the structure.

Simplex Algorithm for 3D Limit Analysis of Roman Groin Vaults

Scipedia content — Tue, 30 Nov 2021 14:46:02 +0100

In Roman Baths the Romans employed groin vaults of great dimensions, with maximum span more than 20 m; simple tools of structural analysis of ancient wide span vaulted halls are still lacking, due to geometrical and material complexity. In this paper we study the collapse behavior, under horizontal static action, of a corner cross vault of the Baths of Diocletian in Rome (Hall I). In the present modeling, masonry is discretized as a system of interacting rigid bodies in no-tension and frictional contact. The computational code consists in a linear programming approach which make use of a series of optimization packages via lower and upper bound techniques of limit analysis. In the paper, a solution strategy based on a modified simplex algorithm has been introduced in order to manage the
large number of contacts given by a 3D block assembly. One more task of the proposed problem consists in a suitable description of the overall 3D geometry, here afforded with a specific pre-processing approach.

Sensitivity Analysis in the Rehabilitation of Historic Timber Structures on the Examples of Greek Catholic Churches in Polish Subcarpathia

Scipedia content — Tue, 30 Nov 2021 14:45:55 +0100

This work concerns structural and sensitivity analysis of carpentry joints used in historic wooden buildings in south-eastern Poland and western Ukraine. These are primarily sacred buildings and the types of joints characteristic for this region are saddle notch and dovetail joints. Thus, in the study the authors focus on these types of corner log joints. Numerical models of the joints are defined and finite element simulations of their statics are carried out. Moreover, a sensitivity analysis is performed in order to describe how the uncertainty of material properties including humidity of some structural members, caused during potential repairs, affect the structural behaviour of the whole connection. This
represents the situation when some degraded logs are exchanged into new wood combining old, and often damp, wood with new and dry logs. A non-intrusive probabilistic approach to the sensitivity analysis is applied and regression-based Polynomial Chaos (PC) expansion method is used to propagate uncertainties.

Senate Building of Canada Case Study: Seismic Rehabilitation

Scipedia content — Tue, 30 Nov 2021 14:45:48 +0100

Ottawa’s landmark Union Station was constructed between 1902 and 1912 to house Ottawa’s central railway station. Located in the Ottawa downtown core, it’s situated a short distance from Parliament Hill and across the street from the iconic Fairmont Chateau Laurier Hotel. In the early 1960s, the train tracks and train sheds were removed and replaced with Colonel By Drive parkway. The building sat vacant for quite some time, until it was revived when it underwent renovations in the early 1970s. A south addition was added with a unique geodetic canopy structure. The former Union Station had officially been adapted into the Government Conference Centre, which it remained until this rehabilitation project 2014-2018, which transformed the building into the temporary house of the Senate of Canada. The building was not accessible to the public when it was a Conference Centre, however since 2018 the building is again open to the public for the first time in 55 years.
The client’s objective for this rehabilitation was to increase useable floor space. A seismic upgrade of the existing heritage building was also required, along with the design of a new east addition. Existing floor plates required upgrading based on new user requirements. High heritage areas of the building had to be maintained in their original integrity and worked into the design upgrade.
Creative solutions were demanded to bring this existing heritage masonry building up to current seismic code, without the structure taking any more room within the floor spaces. Maximizing space was absolutely critical. As well as, ensuring the new building materials were compatible with the existing heritage building materials. Innovation was found in the balance between a minimal intervention approach and upgrading for current code requirements.

Seismic Vulnerability of Heritage Churches in Québec: the Néo-Roman Typology

Scipedia content — Tue, 30 Nov 2021 14:45:40 +0100

Several seismic events have demonstrated the vulnerability of masonry churches. The long seismic history of the Italian territory has provided materials to observe and to study the structural performance of churches. Since the 1976 Friuli earthquake many studies have contributed to the definition of specific damage and vulnerability assessment methods for churches, based on the identification of macro-elements and kinematic mechanisms. In this context, the paper presents the application of a vulnerability assessment methodology developed and currently applied in Italy to a case study representative of the néo-roman church typology in Montreal, Québec. The study is part of a collaborative project between Politecnico di Milano and École de Technologie Supérieure of Montreal. The relevance of such a study derives from the moderate seismicity of Montreal associated to a high density of churches. Starting from a previous inventory of 108 churches in Montreal Island, the Néo-roman church typology was selected to be investigated. Specificities of this typology are the position of the bell tower in the middle of the façade and the interaction between the timber structure and masonry walls. This combination between the façade and bell tower macro-elements requires to reconsider the mechanisms associated to these elements in the original reference method. A detailed survey of the roof and bell tower timber structures of a néo-roman church was done, and a three-dimensional numerical model was developed for a better understanding of this type of structure. Modal analysis of a global model was then carried out and the first results of the modal shapes discussed.

Seismic Vulnerability Assessment of Romanian Historical Building under Near-Source Earthquake

Scipedia content — Tue, 30 Nov 2021 14:45:32 +0100

The ground motion vertical component is generally ignored in the analysis of ordinary building structures, even though observed damages after last earthquakes highlighted its marked influence especially on the response of masonry structures. In the present research work, the effect of ground motion vertical components in case of near-source excitations has been analysed. The investigation has been made on the Banloc Castle, a historical masonry building damaged by the Banat-Voiteg earthquake occurred on December 1991 in the Region of Banloc in Romania. A FEM model of the building, setup with the DIANA FEA analysis software, has been investigated in the non-linear dynamic field. In particular, the records have been referred to the Banloc site, located 7.01 km far from the epicentre with a moment magnitude Mw=5.5 and a focal depth of 9 km. The behaviour of the ground motion components has been characterised by the V/H peak ground acceleration ratio. In order to estimate the influence of the vertical seismic motion in terms of both displacements and stress regime, two different scenarios have been analysed. The first scenario has taken into account the horizontal component only, whereas the second one has analysed the simultaneous effects of three components of the seismic action. Finally, numerical damage patterns have been plotted aiming to simulate the real cracks detected in the case study after the considered seismic event.

Seismic Vulnerability Assessment of Representative Building Typologies from Barcelona‘s Eixample District

Scipedia content — Tue, 30 Nov 2021 14:45:23 +0100

Unreinforced masonry buildings prevail in many old historical centres and urban areas worldwide. These structures may present inadequate seismic performance because they were often designed without considering any seismic resistance requirements. Therefore, they may be highly vulnerable and susceptible to damage caused by earthquakes, even of low intensity.
This work investigates the seismic vulnerability of typical unreinforced masonry buildings situated in the Eixample district of Barcelona, Spain. Most of the buildings of the district were designed only for vertical static loads with slender load-bearing masonry walls and flexible diaphragms. A typical characteristic is the presence of openings with considerable size on the facades. The identification of the main parameters affecting the structural behaviour under lateral loading is necessary to evaluate the seismic vulnerability.
As a first step, a building taxonomy for the Eixample district has been prepared in order to classify the different building typologies by taking into account the influence of the structural features in the overall response. This typology classification serves two aims. The first aim is to empirically evaluate the vulnerability of each category. The second one is to provide the basis for creating a numerical model of a representative building and analyse its seismic performance.
The main objective of this paper is to assess the seismic behaviour of a typical unreinforced masonry structure by means of nonlinear static analysis. For this purpose, a three-dimensional Finite Element model of a representative building has been prepared. Pushover analyses have been performed in two directions (parallel and perpendicular to the façades) aiming to identify the typical failure mechanisms and the seismic capacity.
The performance of the representative building typology, with its typical heterogeneities and irregularities, is compared with that of a reference regular unreinforced masonry structure. Additionally, a parametric analysis is carried out to evaluate the different seismic response by adding more storeys in height. This work is the basis for future analyses devoted to large scale seismic vulnerability assessment of the most representative building typologies of the Eixample district.

Seismic Vulnerability Assessment of a Historic Brick Masonry Building by Fragility Functions

Scipedia content — Tue, 30 Nov 2021 14:45:16 +0100

This paper aims at contributing to the seismic vulnerability assessment of a historic brick masonry building constructed in Istanbul by comparison of the derived analytical and empirical fragility functions. For this purpose, Incremental Dynamic Analysis for each ground motion record was initially performed by series of Nonlinear Time History Analyses on the most vulnerable façade of the case study building modelled using Equivalent Frame Method. By scaling the PGA values of the fifteen earthquake records selected from PEER NGA West2 Data Base, it was aimed to observe the structural response corresponding the all limit states from yield point to collapse and identify each PGA causing the structure to reach these limit states. Herein, PGA and Spectral Displacements were considered as the seismic intensity parameters, and the ultimate storey drifts were referred as Engineering Demand Parameter. Both analytical and empirical seismic fragility functions were derived using lognormal probability distribution. Consequently, the obtained analytical fragility curves for vulnerability assessment of the building were compared with the fragility curves derived according to
European (RISK-UE), HAZUS and Istanbul Building Taxonomies for the same building classification with the case study building in attempt to investigate the concordance of the results.

Seismic Vulnerability Assessment of a 17th Century Colonial Adobe Church in the Central Valley of Chile

Scipedia content — Tue, 30 Nov 2021 14:45:08 +0100

This paper focuses on the seismic vulnerability assessment of the San Judas Tadeo´s church in Malloa (Chile), an iconic example of Colonial Chilean architecture. This small adobe structure is a single-nave building consisting of the main nave, a bell-tower located in the façade, two external wooden galleries and additional units such as the sacristy, chapel, and two services areas.
The Church has survived several strong earthquakes larger than Mw>8. Besides, after the February 27th, 2010 Maule event it showed remarkable resilience due to the implementation of traditional timber retrofits inserted in the earthen walls. The use of traditional wooden devices such as bond beams, corner keys, and wooden gables, proved to be effective solutions against strong earthquakes.
Therefore, this church appears as a relevant case of the use of seismic resistant constructive techniques of the17th century colonial architecture and the study of its seismic behaviour holds great interest and relevance.
Aimed to assess the seismic performance of the monument, a complete preliminary study of the church was carried out using a multi-level approach comprising historical research, in situ surveys, crack pattern analysis, physical and mechanical characterization of materials, and structural analyses. In particular as part of an ongoing research, linear and incremental kinematic approaches of limit analyses have been employed with the aim of interpreting the local mechanisms activated during the 2010 Maule earthquake. In these models, the effect of friction on masonry-to-masonry and timber-to-masonry interfaces was considered with promising outcomes.
This study results prove the general validity in the field of timber seismic retrofitting of unreinforced adobe buildings.

Seismic Vulnerability Assessment Methodology for Historical Buildings with Cultural Value

Scipedia content — Tue, 30 Nov 2021 14:44:59 +0100

Banat seismic region represents the second most important seismic area of Romania. The area is characterized by shallow earthquakes, with a peak ground acceleration ag=0,20g [1]. The city was influenced by several architectural styles, keeping until nowadays many valuable masonry historical buildings. Most of the historical buildings present severe decay due to the lack of proper maintenance
over time. Timisoara was selected to be European Capital of Culture 2021, so the buildings in the historical districts are expected to be visited by a large amount of tourists.
This paper presents the seismic vulnerability assessment of two of the most important historical urban districts of Timisoara. The evaluation is based on existing Italian vulnerability assessment methodology [2], following on-site investigation. Moreover, there is considered also the influence of the cultural value of the historical buildings. Following a set of new proposed architectural-artistic, urbanistic and social-economic factors, there was developed a new investigation form, presented and explained in the paper [1].
In the end, the authors present a detailed empirical seismic vulnerability assessment influenced by the cultural value for historical masonry buildings in Timisoara city, Romania.
This study could help the local authorities to realize prioritization lists for rehabilitation work, considering first the historical buildings that are the most important for the local community identity. The cultural value and the history of a city must be well known and promoted.

Seismic Vulnerability Assessment Method for Vernacular Architecture Considering Uncertainty

Scipedia content — Tue, 30 Nov 2021 14:44:52 +0100

Built vernacular heritage embraces buildings that are not designed by specialists, but are part of a process that involves many people over many generations and relies on empirical knowledge. Its value as a key-element for cultural identity is unquestionable. However, precisely due to its empirical and traditional nature, it is often seen as an obsolete and unsafe way of construction, which leads to its progressive abandonment. This lack of proper construction details and poor maintenance increases the seismic vulnerability of the vernacular heritage. There is an evident need for simplified easy-to-use seismic vulnerability assessment methods for vernacular architecture, given the generalized lack of resources that can be normally assigned to its study and preservation. Most of the times, visual inspection will be the only tool available to carry out the assessment.
Nevertheless, simplified methods demand a deep understanding of the seismic behavior of vernacular architecture. This is a complex task given the great heterogeneity in the geometrical, structural, construction and material characteristics of vernacular buildings. The present works explores the development of a probabilistic method for the analytical derivation of seismic fragility functions of vernacular buildings considering uncertainty in material parameters and structural characteristics. The procedure followed to investigate the effect of uncertainty and to evaluate the influence of a set of key parameters on the seismic response of vernacular buildings is based on stochastic analysis. In the end, a simplified numerical tool is proposed which can be applied based on visual inspection. The process applied and shown here is considered as an example of application and can be replicated in other contexts. It ultimately intends to extend the applicability and reliability of current seismic vulnerability assessment methods.

Seismic Testing of Adjacent Interacting Masonry Structures

Scipedia content — Tue, 30 Nov 2021 14:44:41 +0100

In many historical centres in Europe, stone masonry buildings are part of building aggregates, which developed when the layout of the city or village was densified. In these aggregates, adjacent buildings share structural walls to support floors and roofs. Meanwhile, the masonry walls of the façades of adjacent buildings are often connected by dry joints since adjacent buildings were constructed at different times. Observations after for example the recent Central Italy earthquakes showed that the dry joints between the building units were often the first elements to be damaged. As a result, the joints opened up leading to pounding between the building units and a complicated interaction at floor and roof beam supports.
The analysis of such building aggregates is very challenging and modelling guidelines do not exist.
Advances in the development of analysis methods have been impeded by the lack of experimental data on the seismic response of such aggregates. The objective of the project AIMS (Seismic Testing of Adjacent Interacting Masonry Structures), included in the H2020 project SERA, is to provide such
experimental data by testing an aggregate of two buildings under two horizontal components of dynamic excitation. The test unit is built at half-scale, with a two-storey building and a one-storey building. The buildings share one common wall while the façade walls are connected by dry joints. The floors are at different heights leading to a complex dynamic response of this smallest possible building aggregate. The shake table test is conducted at the LNEC seismic testing facility.
The testing sequence comprises four levels of shaking: 25%, 50%, 75% and 100% of nominal shaking
table capacity. Extensive instrumentation, including accelerometers, displacement transducers and optical measurement systems, provides detailed information on the building aggregate response. Special attention is paid to the interface opening, the global behaviour in relation to the interface separation, interstorey drifts and out-of-plane displacements.

Seismic Stability Analysis of Inca Earthen Walls

Scipedia content — Tue, 30 Nov 2021 14:44:33 +0100

In many places around the world there still exist statues, walls and columns which, despite being located in areas of high seismicity, are still standing and in good conditions after several hundred years. Although Peru is located on a zone of high seismicity, some preColumbian walls are still standing after having withstood many intense earthquakes. The remarkably stable dynamic response of these structures when rocking freely due to horizontal ground motions has been extensively studied [1] [2]. The aim of the project presented in this article is to evaluate the probability of seismic overturning of Inca monuments (XVth century CE) during future strong earthquakes. The Wiracocha temple walls located near Cusco and the Inca trail walls that cross the PUCP campus in Lima were selected for this study. Both earthen walls were modelled as free-standing rigid blocks which could rotate around the corners at their base. A set of synthetic ground acceleration signals were then generated according to the seismicity and ground conditions of both sites. The artificial ground acceleration records were scaled to the uniform hazard spectrum of Peru for return periods of 500, 1000 and 2500 years and different moment magnitudes [3][4]. The rocking time history response of each wall due to these ground motions was then numerically computed and plotted in order to assess the seismic risk due to overturning of these important earthen monuments.
The main conclusion is that these walls will most probably remain standing for many more
centuries.

Seismic Retrofitting of Historical Masonry Heritage Structures: A Case Study of an Adobe Masonry Building in Lima, Peru

Scipedia content — Tue, 30 Nov 2021 14:44:23 +0100

The need for seismic retrofitting on a historical masonry heritage structure raises questions that go beyond the improvement of its seismic behaviour after the intervention. Indeed, principles as minimum intervention or reversibility must be considered before a consensus decision can be reached, especially when this process is just a part of a broader and deeper intervention on this kind of building.
Moreover, the complexity to perform in-situ experimental tests results in the uncertainty on the masonry mechanical properties, which are typically assumed as a homogeneous and isotropic material. All these uncertainties, among others, result in the difficulty to predict the different possible failure mechanisms of the complete structure and its structural behaviour.
Through the analysis of different possible seismic strengthening solutions for a 19th century historical masonry heritage building these issues are tackled. The selected case study is the fort of Santa Catalina, an adobe masonry load-bearing wall building located in Lima, Peru, on which it has been decided to carry out its seismic retrofitting among the complete rehabilitation of the building. The Peruvian coast is classified as a high seismic activity zone, where an 8.0 Mw is expected to occur according to recent studies performed by the Geophysical Institute of Peru.
In this context, this work presents the results of a preliminary characterization of the selected adobe masonry building and the subsequent evaluation of its seismic vulnerability in order to define the fitting solution.
Thus, the ongoing research allows to define an effective seismic retrofit solution and respectful to the building's historic significance.

Seismic Response of Hagia Sophia Church in Thessaloniki Including Soil-Foundation-Structure Interaction

Scipedia content — Tue, 30 Nov 2021 14:44:15 +0100

This study investigates the behavior of “Hagia Sophia” church in Thessaloniki under seismic loading. It is one of the greatest Byzantine churches in the city and it is inscribed on the World Heritage List. The main scope of this work is to estimate the seismic response of the historic structure accounting for the actual foundation and soil flexibility at its base, to find the locations in need for retrofit and finally, to propose possible intervention methods. We simulate numerically the soil - foundation -structure system, and for the properties of the building materials we estimate their strengths with the use of two codes; the EC6 and the Greek Regulation for the structural intervention of masonry (KADET). We simulate soil-foundation flexibility using impedance functions under the foundation according to NIST (2012) provisions. The influence of soil–foundationstructure interaction is investigated. As a reference case, we also consider a fixed-base model to compare the output of the two analyses and highlight the influence of the soil and masonry foundation flexibility on the dynamic response of the church. Finally, we further analyze the intervention method of micropiles as a possible method of enhancement for the foundation of the monument

Seismic Performance of Masonry Cross Vaults through Shaking Table Testing on a Scaled Model

Scipedia content — Tue, 30 Nov 2021 14:44:05 +0100

Masonry cross vaults are among the most widely used typologies of horizontal structural elements for covering spaces of both ordinary and monumental buildings in the European countries. Their seismic vulnerability has been proved by systematic damages and collapses surveyed throughout the centuries. Therefore, the assessment of their structural safety is a crucial issue for the conservation and preservation of historical buildings. Although various methods have been developed and used to analyse both the stability (e.g. equilibrium method) and the dynamic behaviour (e.g. finite and discrete element approaches) of vaulted structures, experimental studies are constantly needed to validate and calibrate models. In this regard, limited experimental studies to understand the dynamic response of vaults have been done. The present paper describes the results of shake table tests on a 1:5 scaled cross vault model made of 3D printed blocks assembled with dry joints, carried out at the 3D LNEC shake table (Portugal). The main aim of the tests is to investigate one of the most typical seismic damage for cross vaults: the shear failure. This type of mechanism frequently affects vaults of lateral aisles and it is mainly caused by a significant difference in stiffness of vaults’ supports. Indeed, the lower stiffness of the central nave colonnade compared to the external wall may induce an in-plane shear distortion of the vault caused by a differential longitudinal displacement of its opposite sides. Incremental seismic motions are conducted up to collapse using Emilia Romagna earthquake. The results are analysed in terms crack pattern and damage mechanisms.

Seismic Performance Evaluation of Box-Shaped Wall Structures Built with Thick Earthen Walls

Scipedia content — Tue, 30 Nov 2021 14:43:57 +0100

A “dozo-dukuri” is a type of traditional Japanese building characterized by a box-shaped wall structure built with thick earthen walls. This structure is referred to as the dozo structure in this paper. However, very little information on the seismic performance of dozo structures have been provided in the literature. Therefore, we performed a horizontal loading test on full-scale walls produced based on survey results and specifications of earthen walls around the northern Kanto region to determine the walls’ structural performance when receiving a horizontal force (e.g., an earthquake). As a case study, the seismic performance of an existing building was evaluated using the test results. The case study results indicate that if the maximum response deformation angle is equal to that in the calculation result or less, the possibility of a building collapse due to the assumed ground motion is low.

Seismic Fragility Analyses of the Cabinet Stored Artefacts with and without Damping Method

Scipedia content — Tue, 30 Nov 2021 14:43:49 +0100

The Forbidden City, the former Chinese imperial palace, now houses the Palace Museum. It is not only famous for its splendid wooden palace complex, but also prestigious for the millions of precious artefacts stored. The Forbidden City is located in the center of Beijing, which is a high seismic hazard zone. Wooden structures usually perform well during earthquakes because of their large deformation and damping capacities. Meanwhile, most artefacts are fragile due to their delicate shapes and aging issues, and also due to their unanchored place form. Only a few of those artefacts are on exhibit, while most of the others are placed in cabinets and stored in warehouses. This paper focuses on seismic protection of these cabinet stored artefacts. Considering the tremendous amount and the rigorous requirements for moving the artefacts, base isolation is not a favored method. Using base isolation requires lifting the artefacts or cabinets while installing isolation bearings and this is very time consuming because of the rigorous requirements for moving artefacts. Also, artefact damage might happen during this process. Thirdly, much more spaces are required to accommodate the potential isolation deformation. Considering all these adverse aspects, this paper tries to use dampers to connect all adjacent cabinets to enhance the integrity and increase the damping ratio and thus protect the stored artefacts. This method is applicable for both new and existing cabinets. No artefact movement and extra space are required. All the dampers are installed with mechanical buckles and the whole installation is reversible. In order to validate the effectiveness of this method, shake table tests and finite element analyses based on practical cabinet layout with and without this damping method are designed and conducted. Ten ground motions are chosen and used to conduct fragility analyses. The cabinet sliding displacements are chosen as the damage index. Seismic fragility curves of the cabinets with and without dampers are plotted and compared. Results demonstrate the effectiveness of the proposed damping method.

Seismic Damage Scenarios Induced by Site Effects of Masonry Clustered Buildings: a South Italy Case Study

Scipedia content — Tue, 30 Nov 2021 14:43:41 +0100

The present research aims to investigate the influence of site amplification on the seismic vulnerability of the historical centre of the municipality of Baranello in the Molise Region of Italy. Structural and typological characterization of the investigated area has been done according to the EMS-98 scale. The vulnerability assessment of the historical buildings located there has been carried out through an appropriate survey form in order to identify the buildings most susceptible at seismic damage. Furthermore, according to the AeDES form implemented by the Italian Civil Protection Department, the calibration of the typological vulnerability curves of the built-up area has been done based on the seismic motions recorded after the 2002 Molise earthquake. Finally, the local amplification factor, which negatively influences the severity of the seismic damage on the structures, has been taken into account according to the time-domain method. To this purpose, a refined and simplified approach to
foresee the expected damage of the inspected urban sector has been proposed, so to use more appropriately the achieved results for reliable seismic risk mitigation plans.

Seismic Damage Mechanisms for Churches and Damage Sequence: Considerations from a Case Study

Scipedia content — Tue, 30 Nov 2021 14:43:33 +0100

Several high-intensity earthquakes have occurred in Italy in the last decades, causing considerable damage to architectural heritage and pointing out the particularly high seismic vulnerability of masonry churches. A significant research effort has been devoted to develop specific methods for the damage analysis and the seismic vulnerability assessment of these assets. An abacus of damage mechanisms recurring in the church structural components has been developed and has become an important reference in rapid assessment procedures as well as in more detailed analyses. In this perspective, the damage occurred to a church during the Pianura Padana Emiliana (Emilia) Earthquake of 2012 is analyzed here. The damage pattern reproduced, indeed, situations listed in the abacus of mechanisms. The seismic response of the church has been analyzed with different numerical approaches, with complete and with partial models that have allowed an appreciable understanding of the global behavior and of the modality of damage progressing into the mechanisms. The use of vector graphics software tools for 3D modelling that have become available in recent times has allowed to thoroughly understand the constructional complexity of the asset and, consequently, to develop simpler but structurally significant models for numerical analysis.

Seismic Behaviour of La Merced Temple in Morelia, Mexico

Scipedia content — Tue, 30 Nov 2021 14:43:23 +0100

This paper studies the seismic behaviour of La Merced temple, dating from the beginning of s. XVII and is located in the historic center of the city of Morelia considering a set of 9 real September 19, 2017, earthquake acceleration records obtained in seismic stations located near the epicenter, which were used without any scaling factor and then applying a scaling factor to reach the site maximum expected peak ground accelerations for probabilistic return periods of 475 years and 975 years.

Seismic Behaviour Analysis of Diaphragm Arches: Case Studies from Catalan Gothic Churches

Scipedia content — Tue, 30 Nov 2021 14:43:14 +0100

The Gothic style spread, starting from the 12th century, from the Ile-de-France to England and other countries of the Mediterranean area, such as Spain and Italy, according to different configurations and construction techniques, influenced by economic, environmental and social factors. The so-called Catalan Gothic style is not exclusive to the architecture of the Principality of Catalonia but extends to the territories of the Crown of Aragon and Southern France. Its most important characteristics, based on the unitary conception of space and horizontality, had the religious architecture as their major reference. Among other structural elements, the large use of diaphragm arches, built transversally to the longitudinal direction of the nave, has been identified as peculiar both in ecclesiastic and civil Catalan Gothic architecture, although this technique is widely diffused also in the rest of the Mediterranean Europe. The present study focuses on the behaviour of this construction system under horizontal loads. After some brief notes on the history, origins and evolution of diaphragm arches, preliminary outcomes obtained by means of seismic analyses are provided in this paper. In
particular, the possible collapse mechanisms of such remarkable curved structures have been firstly investigated by implementing FEM Models derived from real Catalan examples. Therefore, seismic analyses by means of analytical models have been carried out on the detected cases in order to demonstrate the capacity of this kind of structural skeleton, the importance of geometric ratios and the influence that specific typical elements may have in modifying the seismic behaviour of the analysed structures.

Seismic Assessment of Masonry Towers: The Case of Castellum Aquae System in Pompeii

Scipedia content — Tue, 30 Nov 2021 14:43:06 +0100

The archaeological site of Pompeii is an extraordinary evidence of Roman architectural heritage which comprehends a large number of masonry constructions, buried after the Vesuvius eruption in 79 AD. They were discovered in the XVIII century when renewed cultural interest induced numerous archaeological excavations. In this scenario, the remains of the Roman aqueduct system, i.e. Castellum Aquae system [1], includes a series of approximately 6 m height masonry water towers (WTs). Among the fourteen surveyed, four free-standing towers (i.e. no. 1, 2, 3 and 4) have been investigated in 2015 by means of nondestructive techniques (sonic pulse velocity tests, ground penetrating radar (GPR), ambient vibration tests), aimed at gathering information on the constructive systems and the current conservation state, as well as data on the overall dynamic behaviour. According to the on-site inspections outcomes, 3D finite element models of the towers were constructed and calibrated on the results of operational modal analysis (OMA) [2]. The model updating procedure was able to describe and simulate the soil-structure interaction, introducing a Winkler elastic soil model, and to define the elastic parameters of masonry.
This paper describes the seismic vulnerability assessment of the four WTs, considering both equilibrium capacity and material strength, performing analytical kinematic analyses and numerical finite element modelling.
Aiming at improving the previous studies [3], equivalent modal parameters (i.e. natural frequencies and mode shapes) are used to calibrate analytical models and furtherly refine FE model updating. The numerical models were generated using DIANA software [4], implementing a nonlinear constitutive law for masonry material, i.e. total strain crack model. Afterwards, sensitivity analyses are performed to calibrate both the elastic properties of materials and the Winkler springs’ stiffness. Eventually, analytical kinematic approach and FE pushover analyses (with uniform and modal force distribution) are executed to assess the seismic vulnerability of the WTs, according to Italian code [5].
Results of the analyses are presented and discussed. The study was the occasion to compare the results of kinematic and numerical procedures applied to archaeological structures. The results report the FE approach as more conservative than kinematic model. Thus, the importance to adopt a combined global (numerical) and local (limit analysis) approach in the assessment of archaeological structures is stressed.

Seismic Assessment of Heritage Buildings in Bulgaria

Scipedia content — Tue, 30 Nov 2021 14:42:58 +0100

Earthquakes are some of the most serious causes of degradation and destruction of the heritage buildings. The earthquake can cause different damages, directly and indirectly to the historical buildings and their elements. The biggest part of the heritage buildings was built essentially following empirical rules, refining the proportions of structural elements by an intuitive perception of the structural behaviour. In most cases, this trial took only static actions into consideration, so, since seismic horizontal actions modify the behaviour in a significant way, an earthquake may frequently produce cracks and local collapses. Seismic assessment of heritage buildings is relevant for any preservation project. Using specific investigations and checks, the best retrofit method can be chosen. Based on different case studies, the aim of the paper is to recommend useful framework and easy applicable assumptions for practicing engineers to evaluate the vulnerability of the historic structures and the possibilities of further steps in their development. Seismic assessment of historic buildings remains a challenging task. There is a high level of complexity compared with the
assessment of standard buildings. The assessment and the diagnosis of heritage buildings in seismic areas require an extensive knowledge on the structural typologies and behaviour of heritage buildings. The investigation on previous damages from earthquakes is very important. Adequate and realistic computer modelling of complicated historic structures requires significant designers’ expertise. It is probably best to start with the simplest realistic model and then, if necessary, develop a model that reflects more structural features and complexity. The presented paper investigates the challenges posed by, and solutions needed, to ensure the structural longevity of historic structures. Finding the potential for future development of heritage buildings is an important task of the contemporary construction sector. The paper presents only 3 specific case studies but based on the results it is possible to produce some more general recommendations concerning the seismic assessment, the possibility to identify the vulnerability of historic structures and to give the recommendations for extending the service life of Heritage buildings.

Seismic Assessment of Dutch URM Buildings According to NPR9998:2018 Code with an Equivalent-Frame Approach

Scipedia content — Tue, 30 Nov 2021 14:42:50 +0100

In the last two decades, the province of Groningen, located in the North-East of the Netherlands, has been subjected to an increasing number of earthquakes induced by gas extractions. The existing building stock is mainly composed by unreinforced masonry (URM) buildings not conceived to resist seismic loads. The need of reducing the vulnerability of these buildings by means of retrofit interventions, led to the development and adoption of a new guideline (NPR9998:2018). As regards the seismic assessment of URM buildings using nonlinear static analysis, the guideline includes significant differences with respect to Eurocode 8, which is adopted in other European countries. The more significant differences lay in the description of failure mechanisms and constitutive laws of piers and spandrels, inthe identification of limit states and in the calculation of seismic demand. In the last years, the assessment and retrofit in the region has been carried out using software based on an equivalent-frame strategy: among these, the 3Muri software has been widely adopted. The solver of this program is the research software TREMURI. In this work, a new version of the solver adopted by the software 3Muri, complying with the requirements of the new Dutch guideline, was developed; the tool was then validated with simple examples. To illustrate the specificities of the new guideline, the seismic assessment of a building representative of one of the most widely diffused URM building typologies in the area was performed.

Seismic Assessment and Strengthening Interventions of Atop Single-Block Rocking Elements in Monumental Buildings: the Case Study of the San Felice sul Panaro Fortress

Scipedia content — Tue, 30 Nov 2021 14:42:41 +0100

The paper describes the seismic assessment of the San Felice sul Panaro Fortress (Italy), focusing the attention on the activation of the out-of-plane response of the North walkway, characterized by the presence of an apparatus of merlons which highlighted a significant damage after the Emilia earthquake (2012). Nonlinear kinematic analyses have been performed, referring to a macro-block model and considering both the original configuration and two different possible strengthened strategies. For the definition of the seismic input in terms of floor spectra, the analyses also benefitted from the results obtained for the global response through a detailed 3D model of the whole fortress. The results were coherent with the observed damage after the seismic event, highlighting in this way the reliability of the adopted modelling strategies and analysis method, and allowed to outline possible strengthening solutions targeted to minimize the impact on the monument and guarantee its preservation.

Salt Contamination of Wooden Materials: the Case of Trondheim (Norway) Warehouses

Scipedia content — Tue, 30 Nov 2021 14:42:26 +0100

Warehouses are big architectonical structures mostly made of spruce wood and utilized as storage buildings principally by food traders in Northern Countries. Trondheim’s warehouses currently observable along the river Nidelva, date back between the 17th and half of the 19th century were mostly used to stock and process fish. Therefore, where the food goods were stored, residuals are expected to be still present and/or to be responsible for the formation of alteration products on the wooden surfaces as well as inside the wooden structure. Here we propose a characterization of residual and neo-formed compounds inside and on the surface of wooden logs by means of vacuum microbalance that allowed both to individuate the type of salts, as well as, to estimate the maximum water film thickness adsorbed on the wooden samples at 93% of RH. These data have been related to variations in the acoustic emission (AE) intensity detected at the log surface and to the wood moisture content measured with capacitive and resistance operating moisture meters. The application of three independent techniques have allowed obtaining interestingly information indicating their potentiality as decay assessment techniques in the field of historical materials and specifically in the study of salts weathering on wood. The methodology allowed identifying a clear relationship between the amount of water in logs as a function of their distance from the ground and variations in the amplitude of the acoustic emission signals.

Safety Assessment of Historic Masonry Structures by Limit Analysis and Deterministic Partial Safety Factors

Scipedia content — Tue, 30 Nov 2021 14:42:17 +0100

Safety assessment of historic masonry structures is a complex problem mainly due to the mechanical characteristics of their material. In the 50’s it was shown that Standard Limit Analysis is suitable for that type of structures and has proven effectiveness for simplified assessment as long as sliding collapse does not occur. This can be formulated as an optimization problem with the intention of calculating the bounds of the load factor, the maximum for static formulations and the minimum for kinematics. In the static case, it is generally assumed that a load factor lower than the referred of the onset of collapse is a safe load factor, but this assumption is false. The collapse due to the lack of stability may occur by increase or decrease of the load factor.
This work presents an alternative to load factor determination to evaluate the safety of masonry structures. The possibility to incorporate one or more safety coefficients is presented applying a deterministic partial safety factor method. An important difficulty for this purpose is that usually these partial coefficients are applied to variables that are referred to the origin of coordinates. This would be appropriate for materials with similar mechanical behaviour under tension and compression stresses, but it is not the case for the typical materials employed in masonry structures like stones, bricks or similar. Materials with non-symmetric tension-compression behaviour have the origin of coordinates over the yield surface or very close to it. For this reason, the origin can hardly be considered as a safe
reference point.
The method proposed in this work consists of the calculation of the interior point further of the yield surface and considers it as the safest point. Considering that point as the origin of coordinates, the deterministic partial safety factors can be calculated.

Safety Assessment of Existing Post-War Reinforced Concrete Bridges. The Case Study of ‘Gerber Girders’ Bridges in Italy

Scipedia content — Tue, 30 Nov 2021 14:42:08 +0100

The interest in the structural maintenance design of existing bridges of the Italian road network is nowadays growing, due to the need to overcome structural inadequacies and/or degradation phenomena. In this framework, the new "Guide-lines for risk management, safety assessment and monitoring of existing bridges" outline the required procedures and tools, identifying the most critical issues of the different bridges’ structural typologies, including Gerber girders in reinforced concrete bridges. A safety assessment of Gerber bridges is thus mandatory as for the presence of joints which do not comply with current design practice and codes as for the occurrence of aging-related decay phenomena, e.g. due to water infiltration. In this context, a novel cross-disciplinary procedure for the assessment of Gerber bridges is here presented, giving an insight on the so-called ‘knowledge phase’. Firstly, the paper analyses the introduction and diffusion of this structural typology in Italy, giving a classification of existing Gerber bridges and focusing on their recurrent degradation phenomena. Finally, a discussion on historical sources which can be used to draw useful information, e.g. construction history surveys, archival drawings, calculation manuals and codes, is presented.

Safe Estimation of Minimum Thickness of Circular Masonry Arches Considering Stereotomy and Different Rotational Failure Modes

Scipedia content — Tue, 30 Nov 2021 14:41:59 +0100

Limit state analysis of masonry arches sets to assess the safety of the structure by determining the minimum thickness that just contains a thrust line. Based on the Heymanian assumptions regarding material qualities and the equilibrium approach to the static theorem it has been explicitly proven for semi-circular arches that both the thrust line and the resulting minimum thickness value is subject to stereotomy (brick or stone laying pattern), while present study demonstrates, that the latter statement holds for pointed-circular arches as well. This is not straightforward, since the number- and arrangement of the hinges at limit state vary subject to the geometry in case of pointedcircular arches, resulting a more complex problem. It is also explicitly shown, that stereotomy might also affect the corresponding (rotational) failure mode (for certain arch geometries). Stereotomy of an existing structure is not always known, hence it is relevant to search for a stereotomy related bounding value of minimum thickness for each of the various failure modes. The potential of the envelope of resultants as a thrust line (resulting from vertical stereotomy) leading to bounding value minimum thicknesses is discussed: as shown elsewhere it bounds the family of thrust lines, hence leads to an upper bound value of minimum thickness in case of semi-circular arches. It is demonstrated however, that this cannot be generalized for other rotational failure modes which occur for circular-pointed arches. The envelope of resultants does not necessarily lead to a bounding value of minimum thickness, and even if it does, it can be either an upper or a lower bound. However, it is found that the range of minimum thickness values is bounded in all possible failure mode types. The necessary conditions are provided for each.

Risk Management and Built Heritage: Towards a Systematic Approach

Scipedia content — Tue, 30 Nov 2021 14:41:51 +0100

This paper discusses the classification of risks as a tool for the identification, the assessment and the management of risks for the built heritage. Existing typologies of risk vary according to the selected criteria on which they are based and their utility within the risk management process. Indicative examples of risk classifications proposed and used in the field of cultural heritage management, as well as in other fields, are examined. The comparison of the selected criteria for analysing risks and the reflection upon their relevant aspects to the built heritage conservation provide a frame for a systematic approach to the built heritage management.

Risk Assessment Methodologies to Safeguard Historic Urban Areas from the Effects of Climate Change

Scipedia content — Tue, 30 Nov 2021 14:41:41 +0100

A systematic and critical review of the existing literature on climate-change riskassessment methodologies for historic urban areas is presented, in view of the increasing likelihood of extreme weather events. Key performance indicators are identified for use in future risk assessment methodologies that address both the elements of historic urban areas as a system and the potential impact of prolonged heat waves. To do so, a systematic search of the existing literature on Web of Science and Scopus was conducted, with the aim of identifying and characterizing existing methodologies on vulnerability and risk assessment for cultural heritage exposed to the effects of a changing climate. The main characteristics of the methodologies that need to be addressed in the near future and key knowledge gaps were identified, among them, the lack of holistic heat-wave risk-assessment methodologies for historic urban areas.

Restoration of the Queen Victoria Market Sheds E-F and J-M, Melbourne, Australia

Scipedia content — Tue, 30 Nov 2021 14:41:34 +0100

This paper discusses the investigations, analysis, and proposed strengthening to Sheds E-F and J-M of the Queen Victoria Market in Melbourne, Australia. The sheds were visually inspected and measured, a point cloud survey was carried out, wind tunnel testing determined design pressures, and timber samples determined species, grade and extent of deterioration. Strengthening designs were in accordance with the Burra Charter – The Australia ICOMOS Charter for Places of Cultural Significance 2013.

Restoration Authenticity or Reality - A Case Study

Scipedia content — Tue, 30 Nov 2021 14:41:26 +0100

In recent decades, the Venice Charter of 1964 [1] has provided the guiding principles for the conservation and restoration of ancient monuments. However, many interpret these principles as applying to historic structures in general, and not just monuments. The articles in the Restoration section of the Charter have several interesting statements (underlines are for emphasis) that are open to interpretation. In many cases, these statements cause a conflict of priorities, especially with funding being the overriding issue. In addition, local and national heritage agencies sometimes take a more liberal approach to restoration, particularly regarding authenticity. The statements under discussion are:
“ARTICLE 9. The process of restoration is a highly specialized operation. Its aim is to preserve and reveal the aesthetic and historic value of the monument and is based on respect for original material and authentic documents. It must stop at the point where conjecture begins, and in this case moreover any extra work which is indispensable must be distinct from the architectural composition and must bear a contemporary stamp.”
“ARTICLE 10. Where traditional techniques prove inadequate, the consolidation of a monument can be achieved by the use of any modem technique for conservation and construction, the efficacy of which has been shown by scientific data and proved by experience.”
“ARTICLE 12. Replacements of missing parts must integrate harmoniously with the whole, but at the same time must be distinguishable from the original so that restoration does not falsify the artistic or historic evidence.” Each of these statements affects the authenticity of the restoration. But, maintaining authenticity of the restoration has to be balanced with the reality of maintaining our heritage buildings on limited resources. Can it be done? This paper discusses these challenges in the context of the 1996 restoration of a threestory, 19th century brownstone.
The paper will include the conflicts with recommendations for an authentic restoration in accordance with the Charter principles. The work was performed on a limited budget and attempted to address the Owner’s desire for an aesthetic solution. Finally, an assessment of the restoration after 23 years will be included

Resilience of Historic Residential Areas Subjected to Natural Disasters

Scipedia content — Tue, 30 Nov 2021 14:41:18 +0100

The paper presents decision support tools developed for municipalities and historic city managers. These exploit the categorization of cultural heritage assets according to their vulnerability in disaster situations. A manual guiding individual cultural heritage owners, users and other citizens of historic areas provides advices on how to prevent or reduce damage and loss to cultural heritage. The recommendations cover pre-disaster, during as well as post-disaster situations and concern both built and moveable heritage. All measures are illustrated with examples taken during real disaster situations. The methodology has been tested during the international research project “ProteCHt2save”
supported under the Interreg CE program.

Resilience and Vulnerability of Historical Centers: the Case of the District of Camerino in the Marche Region

Scipedia content — Tue, 30 Nov 2021 14:41:10 +0100

The seismic events that hit central Italy in 2016, causing extensive damage to cultural heritage and the loss of entire villages, showed the extreme fragility of the Marche territorial system with strong repercussions on the economic and social development. In the historic villages, the high inherent seismic vulnerability of the building makes it difficult to apply regulations oriented to the protection and preservation of historical and cultural values: strategies for the recovery of the buildings seem very complex. The historical building is generally characterized by a high building density, a scarcity of urban voids and an articulated accessibility system. In recent years the Marche region has developed, due to the intensification of earthquakes, a particular susceptibility to seismic risk. The historic centres have shown a scarce capability to adaptation and difficulties in hypothesizing new scenarios after the damage. In this context, we want to define an analytical method of the systemic vulnerability in the historical centres; this vulnerability is considered as a result of the complex interaction of individual structural units, aggregates and urban spaces. The aim is to compare this vulnerability with the effects that the earthquake really had on the buildings: the knowledge of the real behaviour in the
historic centres will guide the research towards the definition of actions aimed at the mitigation of the seismic risk through the reduction of intrinsic vulnerabilities in the building and the implementation of the capability to face the earthquake, in order to develop a “new resilience”. The district of Camerino is taken as a case study; it’s a territorial hub of services and activities as well as being one of the largest inhabited centres affected by the 2016-2017 earthquake.

Research on Architectural Form and Structural Performance of the Brick-Vault Hall Heritage in China. A case study of Yongzuo Temple

Scipedia content — Tue, 30 Nov 2021 14:41:02 +0100

The brick-vault hall building is a special type of architectural heritage in China, which is significantly different from the western masonry arch heritages in terms of architectural form, structure, construction technology and mechanical performance. After hundred years of natural disasters and human factors, these brick-vault hall buildings mostly have a lot of damages in different degrees. In order to understand the architectural form and the structural performance of this typical type of architectural heritage, the brick-vault hall of Yongzuo Temple was taken as an example to study. Based on the survey of three-dimensional laser scanner, the accurate geometrical dimension of the
brick-vault hall of Yongzuo Temple was collected, the architectural form of this building and the relationship between the brick-vault hall building and the official-type timber structure were analyzed and illustrated. The material properties were observed with the on-site non-destructive testing method. Based on the above researches, the finite element model of the brick-vault hall of Yongzuo Temple was established with ANSYS, the structural performance of the brick-vault hall structure under the vertical load and the earthquake load were studied, respectively. Thus, the weak positions of the brick-vault hall of Yongzuo Temple were found out. The results can provide the basis for the conservation of this type of architectural heritage.

Repair Connection with Wooden Wedged Dowels: Preliminary Experimental Laboratory Tests and FEM Model for the Description of the Mechanical Behavior

Scipedia content — Tue, 30 Nov 2021 14:40:52 +0100

The present paper describes the first steps of the research project by the title “Repair connection with wooden wedged dowels. New and alternative repair method that meets the demands of Monument Protection of built substance’s gentle care and material fairness”. The project aims to develop guidelines for static-constructive use of wood-wood repair connections with wooden wedged dowels.
In the research project, the first steps for the description of the mechanical model for the wooden wedged dowels have been approached. Literature about wooden pegs and dowels and built examples of wooden wedged dowels in existing buildings have been analyzed; more, preliminary laboratory tests and FEM simulations have been implemented.In this paper, the results of the preliminary laboratory tests and the parallel development of a FEM model with the aim of describing the deformation behavior of the wooden wedged dowels for the most used wooden species will be presented. The main aims are: a) Analysis of the distribution of the strains / deformations in the dowel and in the connected building components when inserting the wedge. b) Analysis of the risk of opening of cracks in the materials. c) Analysis of distribution of stresses in the dowel and in the connected building elements utilizing FEM modeling calibrated on the experimental results.
Thanks to the evaluation of deformation behavior in the proposed geometrical configuration
and material combinations of wedge, dowel and connected building elements, it has been
possible to understand the general framework of deformation behavior and failure modes for
different combinations of timber density of the connection components.

Repair and Retrofit of a Roman Bridge in Turkey

Scipedia content — Tue, 30 Nov 2021 14:40:44 +0100

This study assesses the earthquake performance of a historical masonry arch bridge in Aizanoi ancient city, which is located in the mid part of Turkey near Kütahya. Aizanoi was the capital of the territory called Aizanitis, located in the area of Phrygia. Historians agreed that Roman settlement in this area started in 3rd millenium BC. The structure is made of stone and has five arches of 5.40m, 6.70m, 7.30m spans. Rise of the arches are varying from 2.70m to 3.65m. Restoration works have completed in 2018. Before the restoration works have been started the bridge was used for vehicles, even for heavy trucks. Today the bridge is using only for pedestrians. After a detailed site investigation, material characterisation and soil tests were performed, ambient vibration test was carried out on site, by placing accelerometers at several points on bridge span to capture dynamic properties of the structure. Different methods such as Frequency Domain Decomposition, SSI were used to extract the experimental natural frequencies, mode shapes, and damping ratios from these measurements. Experimental results were compared with those obtained by the linear finite
element analysis of the bridge. Good agreement between mode shapes was observed in
comparison, though natural frequencies disagree by 8-10%. The boundary conditions of the
linear finite element model of the bridge were adjusted such that the analytical predictions
agree with the ambient vibration test results. According to the total strain crack material
model, the calibrated linear FE model was extended into a nonlinear model then Nonlinear
Static Pushover analyses of the bridge along longitudinal and transversal directions were
performed. Obtained results are in good agreement with previous case studies’ results.
In order to compare collapse load of the bridge with pushover analysis results, kinematic
limit analysis procedure is used to assess longitudinal and transverse seismic capacities. The
capacity curves are obtained by means of limit analysis approach. The study is aimed to
identify on one hand the horizontal load multiplier that activates the kinematic mechanism, on the
other hand the collapse displacement. The numerical results of the structural capacity so found
have been compared with the results available in literature and acceptable agreement of the
results have been obtained.

Renovation of 16th Century Salt House Roof (Lubań, Lower Silesia, Poland) – Case Study

Scipedia content — Tue, 30 Nov 2021 14:40:37 +0100

This article presents next step of the restoration works in the Salt House in Luban, Lower Silesia, Poland. The first stage of technical and conservatory problems which appeared during the restoration process was described in the article “Between conservators theory and modern construction’s codes. Renovation of roof of 16th century Salt House in Luban, Lower Silesia, Poland”, which was presented on 5th International Conference on Structural Health Assessment of Timber Structures, 25-27 September 2019, Guimarães, Portugal [1].

The Salt House in Luban, Lower Silesia, Poland was erected between 1537 and 1539. This historic building is located between medieval defense walls, and it was used as a storage house for salt and grain until the end of the 18th century.

The technical documentation was prepared in 2016, which included 3-D scans of roof truss repair, as well as technical codes and restoration works. During the first phase of the works, the author of this article, who is also a Supervising Engineer, and an expert of the Ministry of Culture and National Heritage Republic of Poland, discovered a lot of discrepancies between the technical documentation and reality. The differences as well as the attempts to adjust restoration works and the technology of works were widely presented in an article at the SHATiS’19, Portugal.

The authors of this article want to show the problems that appeared during the continuation of renovation works and their solutions with reference to historic timber and masonry structures.

Reinforcement and Consolidation of Masonry Structures. Successful Cases Implemented: From the Study to the Execution Phase

Scipedia content — Tue, 30 Nov 2021 14:40:29 +0100

Traditionally, reinforcement and consolidation of masonry structures has been done according to one of the following approaches, or a combination of them: By using materials with a very different nature and behaviour from the original ones in the reinforced structure or by increasing the section of those structures, increasing, therefore, their hardness. The first approach could unleash serious setbacks in the original structure. Using materials with high elastic modulus on more flexible elements might generate new tensions in the system, which previously did not exist, compromising the reinforcement intervention. The second approach implies increasing significantly the structural geometry and, therefore, its own global hardness.
The modern approach, which reinforcement and consolidation of masonry structures pursue, is solving both, different nature of materials and sectional increasing. It is done by using compatible materials with the original structure, combining the elastic behavior of them and assuring the original breathability, and implementing low thickness interventions in order to do not modify the original hardness.
The proposal of a reinforcement system compatible with the historic and architectonic nature of the structure, is based on a mineral matrix of hydraulic natural lime, GeoCalce F Antisismico, combined with basalt fiber fabrics (GeoSteel Grid) or galvanized steel unidirectional bands (GeoSteel HardwireTM). With this system typology, it is ensured an improvement in the mechanical resistances of the structure, based on a simple and low thickness application.
The aim of the exposition is introducing a reinforcement and consolidation system for masonry structures developed by Kerakoll and showing several success cases, in Spain and Italy, reinforced with this system. Each case will be explained from the initial study phase to the execution of the intervention, including the calculations to determine the application to be done.

Reinforced Concrete Floors in Historic Buildings from the Beginning and the Middle of the 20th Century - Examples of Structural Strengthening in the Process of Revitalization

Scipedia content — Tue, 30 Nov 2021 14:40:20 +0100

The paper presents a historical outline of structural solutions of reinforced concrete floors from the turn of the 19th and 20th centuries to the half of the 20th century in the Lower Silesia region of Poland. It is based on the analysis of archival documentation and expert research carried out during the design of the revitalization of historic public and industrial buildings. The structural typology of some simple RC floors slabs used in that time of introduction of concrete into construction life as well as constructional solutions of buildings erected in western Poland in those days are presented. Nowadays, while some of these buildings undergo refurbishment process to adapt them to new functional aims these RC floors have to be strengthened using different methods, depending on the assessment results. In some of the presented design study cases assessed technical state and load bearing capacity of floors ensure the possibility of their further use without the need for significant reinforcements, except for the need for surface material repairs. However, in some cases due to concrete deterioration processes and loss of its durability, despite necessity of material renovation, structural strengthening methods needed to be applied. For example, increasing the load bearing capacity of floors by making additional concrete layers cooperating with the existing reinforced concrete slab or by changing the static scheme by making new supports up to the complete replacement of floors (not only concrete ones) with modern, concrete rib-andbeam or composite ones were considered.

Reinforced Concrete + Masonry: the ‘Mixed‘ Structure of the Novocomum by Giuseppe Terragni

Scipedia content — Tue, 30 Nov 2021 14:40:10 +0100

With his design of the Novocomum building in Como (1928-29), the famous first example of Rationalist architecture in that city, Giuseppe Terragni began to experiment with a mix of different architectural languages and construction techniques. Within the space of less than a year – from January to October 1928 – Novocomum saw a shift from the traditional to the innovative. Starting out with a weight-bearing structure of brick walls, the development of the project led to the introduction of reinforced concrete, which however did not entirely substitute the former: by 1929, such ‘mixed’ structures were to be seen in many buildings then being created and might be taken as a hallmark of the various forms of so-called Italian modernisms. Within the enclosed building site, work on Novocomum preceded right up to the terraced roof, and would only be unveiled to the unsuspecting citizens of the city once completed (1930), giving rise to a fierce controversy. The paper here proposed draws upon wide-ranging research into the Novocomum project to offer material of great significance for our understanding of the characteristic features, methods and phases of construction work – all aspects that have received little attention in the many studies dedicated to Terragni’s architecture. The research made ample use of the documents now conserved in numerous public and private archives in Lombardy, continually comparing the information therein with the building as it stands nowadays. There was a focus on documents relating to work on the building site, which record each successive phase in construction. This material included: notes, technical drawings, estimates of costs, work reports, calculations, payment records and letters, as well as the documents relating to the tense dispute with the building contractor which involved the architect’s brother, the engineer Attilio Terragni. A systematic analysis of the data thus gathered made it possible to reconstruct the far from straightforward interweave between the different phases in the building’s construction and the various ideas advanced in the project designs. Furthermore, study of the structural aspects themselves could draw upon a 3D graphic model, which made it possible to assembly and dismantle the various parts of the structure and thus understand the articulation of the building more fully. At the same time, study of how the various building materials were used provided a further key to understanding the different components of the weight-bearing structure. Comprising an analytic assessment of the material collected, the study aims to be an important source of knowledge for future research into issues related to the structural behaviour and durability of the building.

Reconstruction of a Masonry Windmill Tower with a Multi-Blade Wind Turbine, Steel Reservoir and Water Supply System

Scipedia content — Tue, 30 Nov 2021 14:40:03 +0100

In the early 20th century, rapid industrial growth around the world enabled the development of many advanced mechanical structures. Some of these structures were successfully used to improve agricultural efficiency or increase people’s comfort. Such a situation was observed in 1910 in the western part of Poland, which at the time was partitioned by Habsburg Austria, the Kingdom of Prussia, and the Russian Empire. In the city of Poznan, a Polish landlord built an advanced structure to automate his farming, using freely available wind energy. At first glance, it was a classic windmill, with a multi-blade wind turbine fixed to the top of a cylindrical masonry tower. However, some additional elements demonstrate the uniqueness of such a structure at the time. One hundred years later, the structure is located at the centre of a rapidly growing area of the city. For that reason, restoration of the tower is complex and requires the reconstruction of damaged or missing elements while observing new safety regulations. In this work, the author presents the basic assumptions necessary for the future renovation process.

Reconstructing the Indoor Climate of Historic Buildings

Scipedia content — Tue, 30 Nov 2021 14:39:56 +0100

In general, a building survey includes geometry, structure, construction, material and history. In historical buildings over the time the building structure and usage can vary greatly. If a room offers good conditions, it will be used accordingly. The usage criteria are not limited to geometric and visual design features but also include thermal comfort. When determining the use of historical rooms and buildings, it makes sense to combine the results of the construction survey and literature research with a reconstruction of the indoor climate. Constructive adjustments, spatial extensions and social developments lead to a deviation from the originally planned and implemented situation over time.
Which parameters have to be known in order to reconstruct the indoor climate of a historic building? This paper uses three examples to describe the requirements and procedure for determining the use of rooms that are no longer in their original state. The reconstructed spaces are an office in a former tobacco factory in Krems (Austria) [1], an art gallery in Yogyakarta (Indonesia) [2] and a traditional residential building is in Jeddah (Saudi Arabia) [3]. Dynamic thermal and hygrothermal simulations of building elements show the ability of materials to influence the indoor climate and the interaction between construction and indoor climate. By monitoring or defining the user’s presence and activities in a room the thermal interaction between construction and indoor climate is calculated. The detection of the airflow around and through the building provides important parameters for the assessment of thermal indoor comfort. The results were compared with the use of space as described in the literature or expected from the building survey.
The method of reconstructing the indoor climate in historical buildings works. The results provide information for evaluating the original situation. With these findings, the potential inherent in a building can be better exploited for the adaptation of historical buildings to changing user requirements or climatic conditions.

Reconstructed Overhanging Battlements. Executive Techniques and their Vulnerability in the Stronghold of Arquata del Tronto (Italy)

Scipedia content — Tue, 30 Nov 2021 14:39:47 +0100

The stronghold of Arquata del Tronto was heavily damaged by earthquakes in 2016 and it drew the attention of the experts in reinforcing historic buildings. They regarded it as a case study, a predicting model of the failure in employing specific construction elements in fortified architecture, whose geometric and material data were only approximately considered. The overhanging battlement is the most seriously damaged part of the building and has raised particular attention and interest. As often happens in other castles and fortresses, it dates back to the late 19th and even more to the 20th century. A first close examination of the building’s repairs shows how the new additions, whose maintenance is difficult, ended in failure. The additions were inspired by ancient details, but nonetheless they are unreasonable from the point of view of structure and durability: they – and even more the irrational repairs of the last decades – are the principal cause of failure. Material decay – closely linked to circumstances and places – has also played a decisive role. An extensive and rigorous historical research is necessary to find the sources and to evaluate their nature and limits, as well as to relate all information to the building, thus operating in close correlation with the building archaeology, by now a so widespread and consolidated research field. Jointly, the written documents and the building itself in its historical stratification allow a better analysis of the structural behaviour , an essential step to achieve an effective restoration planning.

Real-Time Structural Monitoring of Bibi-Khanum in Samarkand (Uzbekistan) Combined with Subsequent Laser Scans

Scipedia content — Tue, 30 Nov 2021 14:39:38 +0100

The Bibi-Khanum Mosque was originally built in 1399-1405 and was one of the largest and most magnificent mosques in the Islamic world during the 15th century. In recent years, the monument underwent several complex reconstructions. Among many other major restoration activities, the inner arch of the portal that collapsed in the 1897 earthquake was restored. The monument has been restored to be one of the best shapes in its history, thus it has become essential to conduct continuous structural health monitoring (SHM) of it to ensure its preservation for humanity. The SHM became the main objective of an ongoing extensive project, some results of which are presented herein. The structural health monitoring consisted of three major phases. The first phase includes a real-time monitoring of the monument by seismometers, which are permanently installed throughout the monument. They are used to monitor the effects of large and small earthquakes and ambient vibrations on the resonant frequencies of all major structures of the monument. By utilizing a system identification approach, the possibility of a structural anomaly development can be detected from the change in its resonance frequency. The second phase consists of subsequent laser scanning that is deployed to monitor anomalies of the monument’s geometry in 3D. The monument’s geometry is captured as a collection of points, which is called a “point cloud”. Laser scanning is planned to be conducted several times a year to capture global movements of the monument due to changes in the elevation of the underground water table in rainy and dry seasons. The third phase focuses on a
development of a finite-element (FE) model based on the as-found geometry of the point clouds. It is calibrated based on the collected data to ensure acceptable correlations with the results of the measurements. The FE model is generated for use in future restoration efforts to evaluate the performance and efficiency (if any) of the proposed restoration measures. Based on the results of numerical simulations and structural health monitoring, preventive measures will be developed. In addition, recommendations for further preservation of the historic monument will be developed. This paper describes the preliminary results of the first phase and current results of the second phase of this multiphase project.

Quantification of the Structural Response of Historical Constructions: Investigation of the Strain Variation at the Acropolis Circuit Wall

Scipedia content — Tue, 30 Nov 2021 14:39:28 +0100

The current study aims to assist the preservation of the structural integrity of historical complex sites, utilizing smart instrumental monitoring / remote sensing. The main idea is that smart instrumental monitoring can provide important real-time information (records) of both the actual natural hazard(s) and the corresponding vulnerability, in terms of structural response and distress of structures and monuments of historically complex sites. The study focuses on the Acropolis Circuit Wall, where strain recordings via Smart Rod optical fibre sensors have been made possible. More specifically, wavelength recordings have been obtained and then converted into strain recordings, while the temperature influence has been taken into consideration. Furthermore, reference measurements have been defined during the initial system operation and then they are used for deduction of subsequent recordings. Strains recorded 2 and 1/2years after the initial system installation are shown, after the deduction of the reference measurements. Finally, strain variation between sensors located at the inner and outer side of the same optical fibre Smart Rod are shown.

Quality and Strength Assessment of Butt Welds in Poland’s Oldest Welded Railway Bridges

Scipedia content — Tue, 30 Nov 2021 14:39:20 +0100

Fitness-for-purpose (FFP) assessment is used for estimation the durability of welded plate girders in Poland’s four oldest welded railway bridges. For the girders, the 20.2 m span length was designed. The bridges were constructed over the years 1937-1939 and now being readied for refurbishment. The first radiographic tests on the butt welds in 18 bridge plate girders were conducted in 1958 during which 101 internal cracks in 49 butt weld splices were found, and which were subsequently riveted. The usefulness of such a strengthening is assessed upon structural calculations for design and service loadings, fatigue tests on specimens with internal cracks in the welds, literature service strength of welds with cracks and design fatigue strength of welds with cracks using FFP assessment. The results provide a unique experimental database on the behavior of welds with inadmissible imperfections. They also allow to assess the likely length of their further service life.

Proposal for a Time-Dependent Dynamic Identification Algorithm for Structural Health Monitoring

Scipedia content — Tue, 30 Nov 2021 14:39:12 +0100

This paper describes the design, test and validation processes of a dynamicidentification algorithm aimed at the time-dependent assessment of modern structures and heritage buildings for civil and seismic engineering purposes. Full validation of the algorithm is performed through analysis of numerically simulated data from an idealized masonry tower. Making use of output-only vibration measurements, the non-parametric algorithm can generate dynamic features results as time-dependent functions for the complete observation period. The algorithm can work in the presence of different dynamic loads and non-linear structural behaviours, close spectral frequency components and noisecontaminated data. Time-dependent structural dynamic parameters that can be computed are modal frequencies, modal displacements, modal curvatures, and higher derivatives of mode shapes. The proposed algorithm aims to be used as the core estimator of timedependent identification methods devoted to the health monitoring of structures and infrastructures, being suitable for a multitude of tasks ranging from the simple operational modal analysis (in pre and post-event condition) to the complex online assessment of the structural response during seismic events for rapid damage identification.

Preventive Conservation for Built Heritage. Analysis of Different Models Around Europe

Scipedia content — Tue, 30 Nov 2021 14:39:04 +0100

This paper explores how preventive conservation for built heritage is promoted and implemented around Europe, compares the different practices, and identifies some of the necessary conditions for them to be effective and successful. It pulls together a broad range of initiatives including recently launched and lesser known schemes. Since Monumentenwacht was introduced in Netherlands, similar inspection service schemes have been launched in nine European countries. Comparative analysis shows a great diversity in their management, the spectrum of services, sources of income and other aspects. Other important models contributing to the improved maintenance of built environment include heritage centres, databases of contractors, one-off campaigns, conservation manuals, and maintenanceenforcement. Interdependencies observed between them suggest that their co-existence is essential for preventive conservation system to be truly effective.

Preserving Historic Bearing Structures by Prudent Integration in New Structures

Scipedia content — Tue, 30 Nov 2021 14:38:56 +0100

For the effective consolidation of damaged historic load-bearing structures, it is necessary for the designer to understand the causes of the damage but also to know and apply the most effective consolidation methods, in order not to affect the cultural value of the building. The problem becomes even more complex for the designer when it is desired only to keep a damaged area of a historic building, which was part of an aggregate of historic buildings. Keeping this area is needed because buildings have been seismically interacting over the past 150 years, and it is necessary to maintain the static equilibrium of the building aggregate.
In most cases, in order to safeguard a damaged historic building, is achieved by consolidating the structural elements composing the building, resulting in extensive consolidation areas, long construction periods and expensive and hard to implement solutions. Additionally, it is challenging to predict the response of the building over time to various actions without continuous monitoring, which is difficult to achieve, because of the disturbance on building occupants.
The paper presents an alternative solution of safeguarding interventions on a historic building, damaged by settlement and earthquakes, through its prudent connection to the load-bearing structure of a new building. The building is located in the St. Gheorghe Square in Timisoara, Romania, located in the Banat seismic area with a peak ground acceleration of 0,20g [1]. This alternative solution saves the historic building from the total demolition, has the advantage of minimal consolidation interventions, but also preserves the historical balance between the buildings of the aggregate. The efficiency of the alternative solution is highlighted by a comparative presentation of the internal forces and deformations recorded in different areas of the historic building, first for the singular building and secondly of the building integrated into the new bearing structure. Internal forces and displacements were obtained following a spatial seismic analysis, performed with the ETABS program. In the same time, photographs of the execution, that present the connection between the buildings and the chosen consolidation solutions used to reduce the seismic vulnerability of the building, are presented throughout the paper.

Preliminary Structural Analysis of the Western Curtain Wall of Elmina Castle, Elmina, Ghana

Scipedia content — Tue, 30 Nov 2021 14:38:46 +0100

Elmina Castle, built in 1482 by the Portuguese, was the first of a series of European trading bases along the west coast of Africa and served as a commercial outpost for over four centuries of trade. The structure was captured by the Dutch in 1637 and became a major hub for the Atlantic Slave Trade. The castle is currently a UNESCO World Heritage Site and a Ghanaian national museum. The building is constructed from a combination of mud- and lime-mortared rough-hewed sandstone masonry. The primary focus of the analysis is the western curtain wall, which faces the only side of the castle accessible by land. A flaring at the base of the curtain wall points to the likely presence of an additional tower located approximately midway along the length of the wall in early Portuguese times. Using a pushover analysis with nonlinear 3D FE under Abaqus/CAE explicit formulation, we assess the stability of the tower-wall system to determine if a historical earthquake could have caused the tower to collapse. During the Dutch occupation, a two-story building, brick vaulted at the ground level, was added along the entire curtain wall. Using 2D plane strain nonlinear models, we evaluate the structural capacity of this vaulted system, considering its sensitivity to the density and the thickness of the loose material above the vault as well as the compressive strength of the rough-hewed sandstone masonry in the walls.

Preliminary Approach for a Prototype of Sustainable Antiseismic Dwelling in Nepal Based on the Historic Vernacular Tradition

Scipedia content — Tue, 30 Nov 2021 14:38:38 +0100

The effects of the 2015 Gorkha earthquake in Nepal revealed deficiencies in the most recent vernacular architecture, which no longer uses wooden reinforcements due to national anti-deforestation laws. It also highlighted the shortcomings found in reinforced concrete architecture, which is generally scanty and poorly reinforced due to the high import cost of construction steel. The geography of Nepal has led to the development of a wide variety of vernacular architecture using local materials such as stone, brick or earth in the form of rammed earth and adobe walls [1]. Moreover, although its tradition in the construction of vaults is not as prominent as in neighbouring regions of India, Nepal has developed its own tradition in the construction of vaults and domes, which are generally self-supporting and made of brick or adobe with lime mortar. The design of a prototype of seismic house in Nepal aims to use a modular housing unit with rammed earth walls and/or walls made of materials recycled from previous earthquakes, as well as tile vaults with bamboo sleepers, and possibly vegetable fibre grids. These avoid the use of imported materials, favouring km0 and sustainable materials while following local tradition. Several potential housing units have undergone linear seismic analysis on finite element models, with variations in planimetric layout and the types of tile vault, from the simpler barrel vault to the sail vault. Both are analysed searching for the best shape in terms of seismic efficiency, evaluating stress and strain state. The results obtained from this preliminary study clearly show that, under seismic actions, the response from the construction system using depressed sail vaults and rammed earth walls with bamboo reinforcements is more efficient and homogeneous in terms of tension and deformation. This is due to the geometric symmetry which determines the same response in several directions, unlike vaults with a characteristically strong directionality (barrel vault). The seismic
response of the prototype described is examined by assessing the influence in terms of thrust and deformation of bamboo reinforcements inside the walls. For this, laboratory tests are used to identify the mechanical characteristics of bamboo to be employed in the finite element modelling and calculation, as the values found in the literature vary depending on the physical and chemical characteristics of the material. This study therefore proposes a more sustainable architectural model with greater antiseismic resistance, always in keeping with local constructive tradition.

Post-Quake Small Italian Historical Centres: Urban Resilience between Rhetorics and Reality. The Case Study of Nocera Umbra after the 1997 Umbria-Marche Earthquakes

Scipedia content — Tue, 30 Nov 2021 14:38:29 +0100

The small and medium Italian historical centres are characterized, among other things, by reconstruction that have occurred over the centuries after earthquakes. While earthquakes determine structural damages, human losses and loss of the functionality of an urban system above all, they may create, at the same time, new opportunities if the urban and socio-economical structures are improved during the reconstruction processes as a whole. These processes and the optimal implementation of planning models within them is not straightforward [1], due to that several issues emerge as a challenge of the reconstruction programmes (decision-making processes, general vision for the entire urban system for instance). According to the literature, although a unique definition has not still been coined, resilience can be defined as the capacity of a system (a city) to withstand and restore after a shocking episode (an earthquake). Mainly in the context of cities [2], some approaches have been framed and experimented by other authors [3, 4, 5]. Starting from a short literature review, focuses on theories and methodological approaches to evaluate urban resilience, this work analyses – through an interdisciplinary approach – the case study of Nocera Umbra twenty years after two devastating earthquakes occurred in 1997. The research represents a first attempt that aims at analysing if the implemented reconstruction strategies have made the urban system more resilient with respect to both the built and the socio-economic environment.

Post-Earthquake Reconstruction of the Historic City Center of l‘Aquila: A Proposal Concerning the Rubble Transportation Problem

Scipedia content — Tue, 30 Nov 2021 14:38:22 +0100

Post-earthquake reconstruction of the historic city Centre of L’Aquila, Italy, can be considered as the largest building site now under operation in Europe. The earthquake that hit the city of L’Aquila on the 6th April 2009 generated a so-called seismic crater that comprises 56 municipalities and concerns an area of almost 2.400 Km2. The earthquake of 2009 destroyed or severely damaged all historic buildings of the city Centre. Nowadays, in 2020 there are more than 8.000 completed construction projects that produced almost 4.000.000 t of removed rubble. The reconstruction process of L’Aquila has been soon defined as “the biggest construction site of Europe”. This experience of managing a huge number of construction projects in the same town highlighted the need of a multi-project coordination of the re-construction activities, and a central co-ordination office has been created. Problems concerning the co-ordination of many construction sites that are located very close to each-other are many and are related to the organization and sharing of different resources: space for tower cranes, access routes for vehicles, space for temporary scaffoldings and space for debris storage and disposal. The programme management of these production resources needs to be based on a General Management plan that is proposed. In particular, the problem of rubble production, transport and storage has been addressed in the plan proposition. In fact, the production, transportation and storage of rubble produced by construction operations can be considered one of the main criteria of the multi-project optimization process needed for the co-ordination of the city reconstruction. As a pilot study, a simulation of project co-ordination of an urban area that includes eleven building blocks under re-construction has been performed with the traditional resource levelling procedure. Therefore, the reconstruction programme schedule of the area has been optimized considering the process constraints due to quantitative limits of rubble transportation and disposal.

Point-Load Test Assesment as Study of Adobe Buildings Damaged after the 2017 Puebla Earthquake

Scipedia content — Tue, 30 Nov 2021 14:38:14 +0100

The 2017 Puebla Earthquake on September 19 struck a big part of Mexico causing the loss of historic buildings in several states, being the state of Morelos one of the most damaged in the whole country. Jojutla de Juarez was the most affected locality of Morelos presenting important structural damages or total collapse in the built heritage, being the traditional earthen buildings, made of adobe bricks, the most vulnerable buildings to seismic efforts.
Some of the causes which contributed to the poor behaviour of the buildings were the improper handling of the constructive systems and materials, the insufficient resistance of the structures and the problems derivate by the foundations. The adobe houses of Jojutla presented a mixture between the traditional building techniques and industrial materials like concrete, bricks, blocks and steel; also with irregular heights and plant layouts and inadequate connections between the walls and foundations and roofs, resulting into a higher seismic vulnerability when the earthquake impacted. Also the adobe bricks presented irregularities in its composition and use of additives which resulted in completely different typologies and the loss of the traditional construction techniques.
There was conducted a study to determine the earthquake resistance of the adobe bricks of the houses in Jojutla, considering that the remaining structures were severely damaged and a whole study of the seismic vulnerability would not be possible due the loss of the physical
buildings. The granulometry and composition of the adobe samples of the buildings were determined as well as the natural aggregates like straw and its proportion. Also the compressive strength of the pieces was tested by two methods: the compression test and the point-load test, in order to obtain the indicative values which could be compared with other patrimonial and vernacular study cases.

Performance of Unreinforced Masonry Strengthened with Bed Joint Reinforced Repointing

Scipedia content — Tue, 30 Nov 2021 14:38:06 +0100

Bed joint reinforced repointing is a strengthening method often used in the Netherlands to counteract settlement damage. This strengthening technique consists of cutting a slot in the mortar joint and installing twisted steel bars embedded in a high-strength repair mortar. Due to the increase in seismic activities, triggered by gas extraction in the region of Groningen (northern part of the Netherlands), it is of interest to investigate whether this strengthening technique is efficient against seismic load.
In order to characterize the performance of the bed joint reinforced repointing using twisted steel bars, an experimental campaign was conducted at Delft University of Technology. A quasi-static cyclic in-plane test on a full-scale wall was performed; similar tests on unstrengthened specimens were available from a previous experimental campaign [1][2] and were used for comparison. Moreover, small scale pull-out tests were performed to study the interaction between the steel bars and the repair mortar.
By comparing the response of unstrengthened and strengthened masonry specimens, it is observed that the use of bed joint reinforced repointing can provide an increase in terms of ductility and displacement capacity, but not in terms of force capacity. Regarding the serviceability limit state, a reduction in crack width and an increase of load at onset of cracking were observed. The preliminary information obtained for the presented case study provides the ground for futher research as well as benchmark for numerical modelling.

Performance Assessment of Basalt FRCM for the Confinement of Clay Brick Masonry Cylinders

Scipedia content — Tue, 30 Nov 2021 14:37:57 +0100

Fibre Reinforced Cementitious Matrix (FRCM) composites have been proved to be a suitable strengthening material for masonry structures in the last years. Moreover, basalt fibres are increasingly used as reinforcement of composites as a more sustainable alternative to glass fibres. The goal of this work is to investigate the effectiveness of basalt FRCM to confine masonry circular columns. A total of eighteen clay brick masonry cylinders were tested in compression. The specimens were cored from two different masonry assemblies and wrapped with one or two layers of BFRCM composite. The stress-strain curves and the gains of strength and strain capacity of confined cylinders compared to the control specimens are reported together with a description of the failure modes.