Scipedia: Documents published in 2021

Patio as a Structural Invariant. Buildings with Patio Facing Adaptive Reuse in Barcelona

Scipedia content — Tue, 30 Nov 2021 14:37:49 +0100

Certain architectural structures have the ability to persist over time when a building undergoes a change of use. This is the case of patios, according to the conclusions of a study focused on the reused buildings of Barcelona recently developed. The survey of this architectural element should enable us to better understand the behaviour of these buildings.
If we define the open-air inner courtyard of a building as a patio, this study is especially interested in those who have the capacity to organize spaces, systematize circulations — along with stairs and corridors — and configure the building as a whole. This set of structuring patios particularly applies in a dense city like Barcelona because their position and size also provide liveability to interior rooms. In light of these qualities, such patios can be regarded as an essential piece of both the formal and the bearing structure of a building.
The location and attributes of these patios can be associated with the potential for adaptive reuse: they can help achieve a lower impact on the architectural and formal structure of a renovated building, when used appropriately. Hence the patio can be seen as an indicator of how a new programme adapts to the existing support. 171 out of 565 buildings documented and analysed in Barcelona — a thirty percent of the overall — have at least one patio of a kind whose characteristics have outlived one or more renovation processes. The percentage rises to 50% in Ciutat Vella and Eixample districts, where density and architectural typology make them particularly relevant.
Buildings with patios match different uses and periods from the 11th to the 20th century. In spite of the expected differences, the studio draws conclusions on the understanding of material transformations and changes of use they have undergone.
In short, with regard to buildings included in this category — both heritage and common ones — this paper helps verify the hypothesis that the very existence of a patio is responsible for the persistence of the internal arrangement and structure and must be carefully considered in future interventions when addressed to extend the life-cycle of a building.

Pathological and Structural Assessment of a Residential Building in Lota, Chile

Scipedia content — Tue, 30 Nov 2021 14:37:41 +0100

The urban development of Lota city (Chile) was strongly influenced by the coal-mining industry during 19th and 20th century. Virtually, the entire city was built, initially, by Matias Cousiño’s Coal Company and, later, by the National Coal Company of Chile (ENACAR). At the beginning of the 21st century, the city began to experience a decline because of the closure of coal mines. This situation affected not only the economy and employment of the city, but also the maintenance of its infrastructure and the conservation of historical buildings.
The “Anibal Pinto Building” is a 5 stories reinforced concrete and masonry structure, built in 1966. Besides of an aggressive coastal environment and poor maintenance, this building has experienced one major earthquake (Mw 8.8 in 2010). As a consequence, cracks, concrete spalding and reinforcement corrosion is observed in several structural elements.
To evaluate the current state of the building and determine it remaining operation life, a structural assessment procedure was implemented based on field explorations, laboratory analysis and numerical modeling. Field explorations considered tests to identify carbonation, humidity, porosity, concrete hardness. While, laboratory analysis included compression test of concrete cores extracted from the building. These investigations were developed with the aim of determine the mechanical properties of buildings materials and for identifying pathologies that affects reinforced concrete.
The experimental data was used to elaborate a finite element model in SAP 2000 to estimate building performance compared to the current seismic regulation in Chile.

Parameter Evaluation in Historical Construction: From Sensitivity Analysis to the Test Planning

Scipedia content — Tue, 30 Nov 2021 14:37:33 +0100

Uncertainties play a key role in the structural assessment in the existing buildings. They are mainly associated with materials, geometries and loads. The reduction of these uncertainties is one of the main challenges for researchers who approach this type of project. The aim of this work is the reduction of uncertainties through a sensitivity analysis. These analyses allow understanding the structural overall behaviour and they are useful to the in-situ test planning. The proposed sensitivity analysis is used as cognitive evaluation, analyzing the influences of each parameter on the structural behaviour, and as improvement assessment, evaluating the effectiveness of the intervention proposals. Furthermore, such approach reduces the impact of the experimental campaign and the intervention proposals, in terms of invasiveness, time and cost. The research is carried out through the selection of a case study, the “Quartel da Tropa” (SC), Brazil. It is used to show how the proposed approach can be applied for the structural assessment of historical buildings. The information collected was elaborated with Historical Building Information Modeling (H-BIM) and analyzed through finite element method software. The proposed research allows increasing the level of knowledge of the historical construction of the Quartel da Tropa, through the sensitivity analysis and the experimental test design of the structure. Such an approach suggests how not only the longitudinal Young’s Modulus (E) and the specific weight (w) of the masonry are the main parameters to avoid significant errors in the results in terms of structural assessment. Indeed, type of wooden species, type of structural connection, different types of masonry characteristic in different structural elements must be considered.

Overview of the Mechanical Properties of Steel Reinforced Grout Systems for Structural Retrofitting

Scipedia content — Tue, 30 Nov 2021 14:37:25 +0100

Steel Reinforced Grout (SRG) is a mortar-based composite recently developed for structural retrofitting, which provides high tensile strength with limited increase in mass and in stiffness, and whose effectiveness relies on the good interaction between steel cords and inorganic matrices. Many companies already supply SRG systems for rehabilitation activities and the scientific community has been working intensively on experimental and numerical investigations to demonstrate their effectiveness for structural applications, which also led to the inclusion of SRG in national and international standards for product qualification and design. However, a clear view of the mechanical properties of these systems is still lacking, due to their variability, which, in turn, strongly depends upon cord layout, textile architecture, and characteristics of the matrix. This paper provides an overview of the mechanical properties of SRG composites on the basis of the tests carried out at Roma Tre University and of the other experimental evidences available in the literature. The results of tensile tests on bare textiles and SRG coupons with different inorganic matrices, and of bond tests on masonry and reinforced concrete substrates are collected and the performances of the different SRG systems are compared. The influence of the mortar matrix on crack spacing, ultimate strain and tension stiffening in tensile tests is analysed. The capacity of the steel cords to ensure a proper shear transfer through interlocking within the matrix and the effect of cord density on failure mechanisms in bond tests are also discussed.

Out-of-Plane Behaviour of Tuff and Brick Masonry Walls Strengthened with FRCM Composite Materials

Scipedia content — Tue, 30 Nov 2021 14:37:17 +0100

Strengthening with composite materials is becoming more and more an effective solution for increasing the structural safety of masonry buildings, often subjected to severe degradation or potentially vulnerable to seismic events. Structural retrofitting can be performed according to different techniques, based on Fiber Reinforced Polymer (FRP) or Fiber Reinforced Cementitious Matrix (FRCM) strengthening systems. The second group of composite systems is usually preferred nowadays thanks to some important advantages such as better compatibility with the substrate, applicability on wet surfaces, fire resistance, permeability and reversibility. Several experimental and numerical studies can be found in literature concerning masonry panels strengthened with FRP and FRCM systems. The knowledge about the use of the latter, nevertheless, is still partially limited, in particular if the out-of-plane behaviour of walls is taken into account, with the experimental and numerical database available resulting mainly restricted to monotonic cases. In this framework, results of an experimental campaign devoted to the study of the out-of-plane behaviour of tuff and brick masonry walls strengthened with different types of FRCM systems will be presented and discussed in this paper, performing also a comparison with available predictive formulas. Experimental results showed, in general, good performance of FRCM composite materials, with a proper exploitation of their tensile capacity, proving their effectiveness for the out-of-plane strengthening of historical masonry walls.

Opus Signinum - Roman Concrete without Pulvis Puteolanis: Example of the Substructures of Diocletian‘s Palace

Scipedia content — Tue, 30 Nov 2021 14:37:09 +0100

The palace of the Roman emperor Diocletian in Dalmatia, a Mediterranean region of Croatia, is an important Late Antique complex, whose most important buildings have been excellently preserved, including their vaults: the brick dome of the Diocletian’s Mausoleum, the stone barrel vault of the so-called Jupiter’s temple, and the vaults of the large substructures of the imperial apartments, constructed in Roman concrete. Because in Dalmatia there was no pozzolana (pulvis Puteolanus) – a volcanic material used for making first opus caementicium structures in the Roman world, the concrete for the vaults of the substructures of the Palace was made with crushed terracotta. This type of Roman concrete was called opus signinum. The vaults of the substructures of the imperial apartments within Diocletian’s palace are important for the research of Roman concrete structures because the whole complex of vaults of various types, covering the area of approx. 150 m by 35 m, has been entirely preserved. In this article, of this variety of vault types, several interesting vault solutions are analyzed.

One Year Static Monitoring of the Milan Cathedral

Scipedia content — Tue, 30 Nov 2021 14:36:59 +0100

The paper focuses on the long-term monitoring of the Milan Cathedral. After a concise historic background on the monument and the description of the sensing devices installed in the church, selected results obtained during the first year of static monitoring are summarized as well as the lessons learned in view of the Structural Health Monitoring (SHM) of the Cathedral. In more details, the time evolution of different static features (i.e. strain of metallic tie-rods and tilt of columns) is presented, along with the correlation between those features and the environmental parameters and the possible minimization/removal of the environmental effects with SHM purposes.

Numerical Study of Pier-Wall Connections in Typical Dutch URM Buildings

Scipedia content — Tue, 30 Nov 2021 14:36:48 +0100

In recent years, the seismic risk in the north of the Netherlands has increased due to gas extraction. Since 2014, the Delft University of Technology started a research program to assess the seismic response of unreinforced masonry (URM) buildings. The Dutch URM buildings are characterized by slender piers and transverse walls. In common practice, the connections between piers and transverse walls are often modelled as rigid, but in real structures these connections may exhibit different behaviour. Especially, since the 1980s, calcium silicate element masonry has been commonly used in Dutch buildings, and vertical continuous joints are present between transverse walls. For this reason, it appears essential to assess the connection strength properties, since its failure can significantly reduce the seismic performance of the entire structure. The first part of this work investigates and compares different numerical approaches to describe the nonlinear behaviour of masonry under lateral loads, simulating seismic action. The second part specifically focuses on the critical issues related to the modelling of vertical connections of Dutch URM buildings. A sensitivity study of the frictional parameters is performed to analyze the influence of the strength of the glued connection on the global response of the URM structure.

Numerical Study of Out-of-Plane Behaviour of Timber Retrofitted Masonry Prisms

Scipedia content — Tue, 30 Nov 2021 14:36:37 +0100

The present study addresses the retrofitting of running-bond masonry walls through the application of oriented strand board (OSB) timber panels aiming to increase the masonry flexural strength and deformation capacity under out-of-plane actions. This paper presents the numerical analysis of masonry prisms to complement the information provided by the experimental campaign developed on flexural performances of timber retrofitted masonries. The numerical model represents the masonry components (brick and mortar) as a three-dimensional volume via volumetric finite elements, i.e. hexahedral 8-node linear brick elements with reduced integration and hourglass control. The nonlinear properties of the mortar joints and the brick units have been calibrated through information that resorts from experimental characterization tests. The numerical damage pattern and load-displacement capacity curve are compared with the experimental observations. A good agreement has been found and, therefore, the calibrated model can be employed in parametric studies, to further analyse the efficiency of the proposed timber masonry retrofit technique, and to more complex structural study cases.

Numerical Simulation on Seismic Performance of Retrofitted Masonry Wall in Historical Buildings Damaged in Earthquake

Scipedia content — Tue, 30 Nov 2021 14:36:27 +0100

Due to the characteristics of lower strength, anisotropy, heterogeneity and poor ductility, historical masonry structures usually show poor seismic performance. During earthquakes, the damage severity of masonry structural members varies with their real capacity mostly. To avoid waste and save resources, the following retrofitting strategies would be determined in comply with the cost-effective principles corresponding to the severity level of the damaged buildings. The mechanical properties as to the seismic performance of the critical load bearing walls in the damaged buildings could be improved by retrofitting and repairing. However, how to reasonably and effectively estimate the seismic performance of the retrofitted wall with some level of damage could be the most critical and challengeable point. Based on the finite element analyses, simulation method for the seismic performance of retrofitted masonry wall with damage in earthquake is developed in this paper. The stress and strain hysteretic model for the retrofitted wall element is proposed to consider the three stage effects: original damage, retrofitting or repair, and reloading. According to relevant codes and research results, the damage level of components is classified in terms of the loss level of the axial and shear capacity as well as the deformability. Damage patterns, hysteretic relationships among different retrofitting methods in terms of the external single side of reinforced mortar layer and external single side of fibre reinforced lime mortar layer are compared and analyzed. The seismic capacity and hysteretic skeleton curve of retrofitted masonry wall specimens with different damage levels are developed and discussed. The operational cost-effective retrofitting schemes for masonry walls with different damage levels are proposed.

Numerical Simulation of Traditional Timber-Masonry Buildings Subjected to Lateral Loads

Scipedia content — Tue, 30 Nov 2021 14:36:16 +0100

Existing heritage buildings are often composed of diverse structural typologies, representing a challenge for structural analysis. This work investigates the use of nonlinear static analysis to assess the seismic behaviour of hybrid timber-masonry buildings. The proposed methodology includes the use of Lumped Plasticity Models (LPM) and Macro-Mechanical Finite Element (FE) approaches to simulate the response of structures composed of timber frames and masonry walls. Benchmark experiments on timber and masonry specimens subjected to lateral loads are used to calibrate the constitutive laws governing the behaviour of the proposed models. The calibrated models are used to appraise the seismic response of an existing timber-masonry building located in the historical centre of Valparaíso (Chile). The results predict the nonlinear acceleration-displacement capacity of the buildings, as well as the expected damage of the structure, revealing the potential local and global failure mechanisms.

Numerical Modelling of the Seismic Performance of Romanian Traditional Timber-Framed Buildings

Scipedia content — Tue, 30 Nov 2021 14:36:05 +0100

Traditional architecture made of timber-framed masonry (TFM) system is widespread around the world and has already been recognized as a unique cultural heritage to be preserved. These structures have shown a good seismic performance compared to other typologies because their configuration and construction details were constantly updated as soon as the builders addressed the causes of damage mechanisms when earthquakes occurred. Regarding this typology, Romanian TFM structures can be considered a representative example also because they experienced several seismic events showing their good earthquake-resistance. Although these buildings are still constructed and inhabited nowadays, no recommendation is provided in the Romanian building code and its structural behaviour is not properly characterized yet. Bearing in mind that the building’s global response depends on many parameters such as the performance of its structural elements and their interaction, the calibration of shear walls is crucial to define the non-linear behaviour under cyclic loading. A simplified modelling strategy was chosen to simulate TFM wall response consisting of an equivalent frame with linear elastic elements and non-linearities lumped at the joints by using OpenSees. After calibrating the wall response according to the experimental campaign performed at Technical University of Civil Engineering of Bucharest, the panel was adapted to model a representative Romanian TFM building whose dynamic properties were evaluated by eigenvalue analysis and their potential calibration is proposed based on the ambient vibration tests.

Numerical Modelling of Masonry Arches Strengthened with SFRM

Scipedia content — Tue, 30 Nov 2021 14:35:52 +0100

The adoption of effective strengthening techniques of historical constructions is one of the most widely debated aspects in structural engineering. Within this topic, the application of steel fiber reinforced mortar (SFRM) has been recently proposed as a low invasive and effective way to obtain a considerable structural benefit in the safety of existing masonry structure. To this purpose, in this paper the experimental results obtained on a circular masonry arches are presented. The considered specimens, subjected to a vertical increasing static load, is tested in the unstrengthened and strengthened configurations, and is part of a wider experimental campaign. After presenting and discussing the experimental results, they are compared with those relative to numerical simulations conducted by means of a discrete macro-element (DME) strategy, based on a simple mechanical scheme, able to model the nonlinear behavior of masonry structures with a limited computational effort. Such an approach is here extended to model the SFRM strengthening technique accounting for the main failure mechanisms associated to the combined presence existing masonry and the additional strengthening layer applied at the intrados of the arch. Numerical and experimental results demonstrate the efficacy of the proposed retrofitting strategy both in terms of bearing capacity and increase of ductility.

Numerical Investigations for Assessing the Seismic Performance of Multi-Tiered Nepalese Temples

Scipedia content — Tue, 30 Nov 2021 14:35:42 +0100

In this study, the seismic performance of old multi-tiered temples in Nepal has been addressed using three different computational approaches, including a) linear elastic; b) nonlinear static; and c) nonlinear dynamic analyses. Also, a sensitivity study was undertaken to understand the influence of wall thickness and height of Nepalese temples on their seismic behavior. Vertical oscillating modes using the elastic response spectrum of the Nepalese Building Code were obtained using linear analysis. Nonlinear static analysis (NLSA) were implemented to obtain the load carrying capacities of different in geometry temples e.g. different thickness of central core walls and number of tiers. Additionally, nonlinear dynamic analysis (NLDA) using the Finite Element Method (FEM) were performed to evaluate the characteristic tensile damage patterns. The results comparatively indicate the weakest zones depending on wall thickness, central core slenderness, opening distribution, box-like confinement, vertical misalignment of walls and so forth. Also, the results of the NLDA affirm high vulnerability of the multi-tiered temples showing extensive cracks at relatively low peak ground accelerations. It is anticipated that outcomes of this study can help practicing engineers to understand how these structures behave when subjected to seismic loads and provide insights towards their strengthening and retrofitting.

Numerical Investigation of the Retrofitting Interventions of the San Benedetto Church Complex in Ferrara (Italy) from a Seismic Vulnerability Perspective

Scipedia content — Tue, 30 Nov 2021 14:35:34 +0100

The San Benedetto church complex is an iconic architectural heritage asset of Ferrara, an attractive small city in the North of Italy. This paper investigates two separate parts from the complex, respectively the church, and the bell tower. The construction of the church dates back in the XV century, and many modifications were carried through years. During the second world war the church was severely damaged and then was fully restored to the original design. The bell tower instead is a typical tower of northern Italy, notably inclined by 3°. In the last decade, severe earthquake sequences occurred in the nearby areas, and the occupancy and safety of the structures were compromised. Several observed damages impelled upgrading measures, and consequently, many different retrofitting interventions got executed. Advanced numerical simulations are conducted in order to estimate the seismic vulnerability of each structure, by means of non-linear dynamic analysis. A critical historical evolution of the structure is considered, and two models for each structure are conceived respectively. The church models consist of 1) post-war reconstruction modeled with two distinct materials; 2) post-earthquake intervention with repointing technique and composites. The bell towers models consist of 1) the non-retrofitted tower; 2) the model with steel hooping bars. A comparative analysis is carried out based on the numerical results highlighting the pros and cons of each modeling technique and the efficiency of each intervention. Structural stiffening incorporated with a non-uniform distribution of the resisting capacities of the load-bearing elements highlights the seismic vulnerabilities. The necessity for the advanced numerical simulation emerges by the evidenced vulnerabilities in the performed simulations concerning the overall structural safety.

Numerical Development of a Strengthened Wall-to-Diaphragm Seismic Connection: Calibration and Application on a Building Prototype

Scipedia content — Tue, 30 Nov 2021 14:35:22 +0100

Effective wall-to-floor connections are crucial components of historical buildings to avoid dangerous mechanisms under seismic actions. Existing buildings often present poor friction-based links between timber floor and masonry wall and are not able to ensure the so called “box behavior”, necessary for the correct distribution of seismic forces. Nonlinear static analysis is one of the most common tools for the seismic assessment of unreinforced masonry buildings considering advanced nonlinear materials description and allowing for different approaches. The selection of a proper control node, for the definition of the pushover curve, is fundamental and sometimes controversial. Moreover, connections are modelled as simply fixed or absent at all. Dynamic nonlinear analysis seems preferable even suffering from a higher computational effort.
On the bases of previous experimental campaign developed at the University of Minho, the pull out behavior of a strengthened and unstrengthened masonry-to-timber connection was simulated numerically using OpenSees software. The connection model considers strength degradation and pinching, in agreement with the experimental behavior, and is validated from the energetic point of view, suitable for being included in a global finite element model to study the influence of the hysteretic energy dissipated within the connections on the overall seismic response.
This paper describes the calibration process and the application of the connection model into a unreinforced masonry prototype using nonlinear dynamic analysis under real seismic inputs. Both strengthened and unstrengthened configurations are implemented and results compared. The selected model is part of the blind prediction competition organised within the SERA-AIMS project involving the shaking table test of a half-scaled aggregate.

Numerical Analysis of Historical Reinforced Concrete Shell

Scipedia content — Tue, 30 Nov 2021 14:35:11 +0100

This article is focused on the numerical analysis of the historical structure of the reinforced concrete shell. Shells form the roof of the tram depot. It was built in the 50s of the 20th century. The shells are conoid shaped with a control curve in the form of a catenary. The construction of the depot began to show excessive deformation and lose its stability. At present, the depot is out of service and the shells are temporarily supported. This prompted the commissioning of a diagnostic survey and numerical analysis of the structure. The diagnostic research revealed the quality and strength of the concrete, the reinforcement of the structure, the actual thickness of the shells, the structure of the roof cladding and defects in the structure (cracks, etc.) At the same time, the bottom surface of the whole structure was scanned with a 3D scanner and selected points of the structure were measured by geodetic methods. Numerical analysis focused on one shell at the edge of the depot structure. The model was created in Atena 3D software. The main aim of the analysis was to determine the behavior of the structure under load and to predict the ways of its deformation for different loading methods to determine the possible reason for the current deformed shape. Consequently, compare these predicted behaviors with the real deformed structure, whether its deformation corresponds to normal behavior.

Novel Constitutive Modelling Approach for Shape Memory Alloys Vibration Control Devices

Scipedia content — Tue, 30 Nov 2021 14:35:01 +0100

One of the main fields of shape memory alloy application in civil engineering is oriented on mitigation of earthquake effects on structures. Vibration isolators that incorporate elements made of SMA take advantage of its characteristic phenomenon of nonlinear hysteretic response, also known as superelasticity. In this work, authors presents an approach to phenomenological modelling of SMA by using rheological schemes. One of the advantages of this approach is a possibility of formulation of constitutive relationships as a set of explicit differential equations. As an illustration of validity of the formulation, authors present the response of single degree of freedom oscillator that incorporates SMA elements modelled by different existing SMA models. The response obtained based on the model that uses rheological schemes is compared with Lagoudas thermodynamic constitutive SMA model and simplified material model. All of the compered models are found to match well and show important reduction in displacement transmissibility.

Nonlinear Structural Analysis of the Elliptical Dome of the Church in the Universidad Laboral, Gijon, Spain

Scipedia content — Tue, 30 Nov 2021 14:34:50 +0100

The Church of the Laboral University of Gijón has the world's largest elliptical masonry roof with 40.8 meters of mayor axis. This big structure is vertically supported with no columns using twenty pairs of masonry ribs crossing each other, and horizontally supported by means of two elliptical ring beams located at the top of the Church. In order to study this historical building, this paper presents the overall three-dimensional structural numerical analysis of the Church, taking into account different material nonlinearities - including masonry and reinforced concrete - as well as geometrical nonlinearities, such as contact effects among the different structural components of the building. Furthermore, a coupled thermal-structural analysis was carried out considering the summer temperature distribution and the Spanish standard rule dead and live loads. The most relevant results, in terms of maximum displacement, stress and, cracking and crushing phenomena are presented. Finally, valuable information from the interaction among the structural elements of the Church are discussed and the most critical points of the building are located, giving place to the most important conclusions of the nonlinear numerical analysis of this interesting structure.

Nonlinear Behaviour of Two-Whyte Stone Walls

Scipedia content — Tue, 30 Nov 2021 14:34:39 +0100

Engineers work hard to convert the highly uncertain and nonlinear behavior of historic masonry structures into something that can be understood with mathematical certainty. Therefore, practical and also accurate structural analysis techniques are still needed for the preserve the historical monuments as a huge cultural heritage. In this context, determining the mechanical properties of historical walls under in-plane and out-of-plane lateral loadings is one of the most important aim. This study aims to investigate the three dimensional (3D) nonlinear behaviour of stone walls subjected to a combination of lateral and vertical loads using approprate constitutive numerical modeling. For this purpose, a simplified micro modeling approach has been proposed for the 3D nonlinear finite element analysis (NLFEA) of stone wall. The dry-stone masonry wall from the literature has been used in the verification step for the proposed model. After that, the new two-whyte stone wall has been constructed in accordance with the original material characteristics derived from the experimental studies and tested under shear compression. Finally, numerical results of NLFEA and experimental results of walls have been compared. It was observed that the numerical analysis results are well matched with the experimental ones.

Non-Destructive Techniques in the Consolidation Works of the Church of S.M. of Itria in Piazza Armerina (Italy)

Scipedia content — Tue, 30 Nov 2021 14:34:31 +0100

A real case of consolidation works is presented in which only field testing methods can reveal the causes of instability. This paper is an update of the one presented at the SAHC 2018 conference, concerning the study of the partial collapse of the Church of Itria in Piazza Armerina (Sicily, Italy). The previous paper beared hypotheses and design solutions based only on indirect investigations, theoretical formulations and checks with software. The consolidation works, started in November 2018 and still in progress, have made it possible to formulate new and documented hypotheses on the collapse and to integrate and partly modify the solutions hypothesized previously. In particular, the reconstruction techniques of the wall and chains have been confirmed. The new interventions have, instead, concerned the consolidation of the foundation soil which was found to be insubstantial,following electrical tomographic investigations, due to the presence of voids. At the same time, inspections were carried out on an old masonry sewage pipe which revealed several points of discontinuity through which large quantities of water entered under the walls of the church causing the removal of inconsistent elements from the ground. At first, the reconstruction of the collapsed wall was done and the restoration of the existing wall structures, to eliminate the causes of the collapse through the intervention on the sewage pipe and filling the voids under the foundations. The most important intervention, which required the use of innovative materials, forefront equipment and skilled
labor, involved the filling the voids under the foundations through perforations every 50 cm, both on the inner and outer wire of the collapsed wall. Clamped canes were set in order to intercept the voids highlighted by the tomography. A 100% expansive mortar was injected at low pressure through the canes, filling one cane at a time and progressively raising the point of exit of the mortar until the higher far end. After this consolidation, the foundation and the wall were rebuilt with local limestone ashlars to have fair faced aspect as the original masonry. At the end of the work, further tomographic tests are planned to verify the validity of the interventions carried out.

Non-Destructive Techniques for Characterising Earthen Structures

Scipedia content — Tue, 30 Nov 2021 14:34:21 +0100

Earthen architecture is one of the most relevant building technologies among heritage structures. However, mechanical properties are commonly obtained from destructive tests. To contribute at changing this trend, two non-destructive mechanical techniques (ultrasound and modal analysis) are studied to determine their ability at characterizing earthen materials and their possible correlation.
To achieve these purposes, twenty cubic-shaped earthen specimens were produced for testing the capability of ultrasound transmission method to control moisture content and its evolution during drying process at different environments. Additionally, a real-scale rammed earth wall was built to assess the feasibility of using ultrasound technique to determine elastic dynamic Young modulus. This analysis was validated by indirect comparison with experimental modal analysis test results.
The most important findings are that the relationship between moisture content and ultrasound transmission speed is linear. This information is useful to control the drying process of earthen materials and to control the moisture content distribution on larger in-service structures. Finally, numerical simulation using ultrasound transmission data as input information allow to predict the vibrational response of the tested wall with an error around 3%.

Non-Destructive Documentation Methods for Future Seismic and Damage Analysis of Modern Heritage Buildings using Contemporary Tools

Scipedia content — Tue, 30 Nov 2021 14:34:13 +0100

This paper presents a comparative approach between a digital documentation workflow of a hyperbolic paraboloid heritage building using contemporary tools versus a traditional documentation technique. This documentation was undertaken to better understand the building’s structure, its evolution, and to assess the performance of this modern concrete structure for future seismic and damage analysis. Furthermore, this paper discusses the challenges related to producing a Heritage Building Information Model (HBIM) of this building using point cloud data in Autodesk’s Revit BIM-authoring software. This project states the importance of a parallel study between the traditional and the contemporary documentation methods; which led to discoveries about the current state of the extrados in the hyperbolic parabola after several earthquakes. Upon analyzing the HBIM and comparing it to the historical drawings, we discovered a gap between the moisture barrier membrane and the concrete shell. Visualizing the building in 3D provides a deeper and more accurate understanding of the currentstate of this pavilion and is one of many advantages of using digital technologies. The insights provided by digital documentation techniques and analyzing the historical images of the pavilion showed that the curvature of the pavilion had changed over time. The results that we found imply two hypotheses. First, the profile of the curvature had been modified due to earthquakes, and second that the modification was due to improper maintenance of the pavilion, namely, multiple additions of the membrane layers. This could not have been detected by solely relying on traditional documentation techniques.

Non-Destructive Assessment of the Adhesion at the Interface Between FRCM Reinforcements and Masonry Substrates by Non-Linear Ultrasonic Technique

Scipedia content — Tue, 30 Nov 2021 14:34:03 +0100

The strong diffusion of Fiber Reinforced Cementitious Matrix (FRCM) composites for the reinforcement of historic masonry constructions requires suitable experimental techniques for assessing possible defects in the adhesion between FRCM and masonry, and between FRCM layers. To this aim, in this paper, an innovative nonlinear ultrasonic approach based on the Side-band Peak Count (SPC) technique is proposed. This approach is discussed and validated through experimental tests made on tuff substrates reinforced with FRCM mortars embedding a basalt fibers grid and having known artificial defects at the adhesion between tuff and FRCM as well as in the fiber grid

New Strategies to Assess the Safety of Unreinforced Masonry Structures Using Thrust Network Analysis

Scipedia content — Tue, 30 Nov 2021 14:33:53 +0100

This work develops new strategies to robustly apply Thrust Network Analysis (TNA) for the assessment of unreinforced masonry (URM) structures studied within the frame of limit analysis. It formulates and solves a nonlinear optimisation problem on thrust networks considering relevant constraints for the assessment of URM structures. Geometrical and force constraints are include such as the consideration of the structural envelope and bounds on the reaction forces. The objective functions studied correspond to the minimum and maximum horizontal thrusts of the vaults. To evaluate the level of stability of an existing structure, this work develops a methodology to estimate the geometric safety factor (GSF) and the minimum thickness of masonry vaults by solving sequential optimisation problems for increasingly tightened geometrical bounds. This procedure is implemented in a Python-based, open-access tool within the COMPAS framework and illustrated here on two- and three-dimensional applications that are relevant for the structural analysis of historical constructions.

New Lightweight Structures and Historical Heavyweight Structures in Conservation

Scipedia content — Tue, 30 Nov 2021 14:33:45 +0100

At the end of the 19th century, an architectural style called Neomudéjar became quite popular in some areas of Spain. Very much like other historicist European styles in the same years, the Neomudéjar sought to recreate the local medieval architecture. The use of faced brick façades with complicated bonds -formed by stretchers and headers in and out the main wall plane- lead in term to a wide variety of results that resembled Arabic architecture. The brick façades of the Neomudéjar buildings are ideal case studies for the analysis of the local behaviour of masonry structures, especially regarding problems of stress concentration. There are several methods for studying the global behaviour of masonry structures – from the classic thrust line to the limit analysis tools – but, as the average stresses taken over by structural masonry elements are usually well below the compression strength of the constituent material, the classical methods of analysis are designed to verify only the global stability. Local behaviour, on the other hand, is quite elusive, especially when the properties of the material are uncertain. In such cases stress concentrations might appear, resulting on stress currents and low stress islets. A particular case of these phenomena occurs in the bonding of Neomudéjar façades. Local concentration of stresses is especially likely in these bonds, given the peculiar relative position of some bricks with respect to others. The paper proposed will use one of these buildings, the Aguirre Schools (Rodríguez Ayuso, Madrid, 1886), as a case study to evaluate local behaviour. Starting from a geometrical hypothesis of the internal distribution of the material based on recent photogrammetric surveys, and using conventional software of parametric design, the paper will describe a numerical model based on a non-deterministic random algorithm, although limited in its number of solutions, to discuss later the validity and scope of them. The limitations of the standard hardware in which these design tools are usually handled will also be considered in the discussion.

Neomudejar Architecture and Analysis of Local Stresses of Masonry Structures: The Escuelas Aguirre Case Study

Scipedia content — Tue, 30 Nov 2021 14:33:36 +0100

At the end of the 19th century, an architectural style called Neomudéjar became quite popular in some areas of Spain. Very much like other historicist European styles in the same years, the Neomudéjar sought to recreate the local medieval architecture. The use of faced brick façades with complicated bonds -formed by stretchers and headers in and out the main wall plane- lead in term to a wide variety of results that resembled Arabic architecture. The brick façades of the Neomudéjar buildings are ideal case studies for the analysis of the local behaviour of masonry structures, especially regarding problems of stress concentration. There are several methods for studying the global behaviour of masonry structures – from the classic thrust line to the limit analysis tools – but, as the average stresses taken over by structural masonry elements are usually well below the compression strength of the constituent material, the classical methods of analysis are designed to verify only the global
stability. Local behaviour, on the other hand, is quite elusive, especially when the properties of the material are uncertain. In such cases stress concentrations might appear, resulting on stress currents and low stress islets. A particular case of these phenomena occurs in the bonding of Neomudéjar façades. Local concentration of stresses is especially likely in these bonds, given the peculiar relative position of some bricks with respect to others. The paper proposed will use one of these buildings, the Aguirre Schools (Rodríguez Ayuso, Madrid, 1886), as a case study to evaluate local behaviour. Starting from a geometrical hypothesis of the internal distribution of the material based on recent photogrammetric surveys, and using conventional software of parametric design, the paper will describe a numerical model based on a non-deterministic random algorithm, although limited in its number of solutions, to discuss later the validity and scope of them. The limitations of the standard hardware in which these design tools are usually handled will also be considered in the discussion.

Multi-Modal Analysis of Vibration and Meteorological Data for Structures on the World Heritage Site “Battleship Island”

Scipedia content — Tue, 30 Nov 2021 14:33:25 +0100

This paper reports the results of vibration and meteorological observations of a buildng built on Hashima, Nagasaki, southern part of Japan, which was registered as a World Heritage Site in 2015 [1], and analyzes its dynamic characteristics. Hashima is called "Battleship Island" because its appearance resembles a battleship due to the many buildings standing upon it. The structure contributing most to the battleship appearance is No. 3 Building. An accelerometer and a weather sensor have been installed in No. 3 Building for long-term measurements. Multi-modal analysis of vibration and meteorological data was performed for 5 months, and the dynamic characteristics of No. 3 Building were examined.

Monitoring of Indoor Environmental Conditions of the Kvernes (Norway) Stave Church

Scipedia content — Tue, 30 Nov 2021 14:33:16 +0100

The proposed study deals with environmental data collected in the Kvernes stave church, belonging to the Møre type. The nave and the chancel belonging to the original structure, probably dated back to early 1600, are one of the few cases – among the 28 existing Stave Churches - still maintaining the internal wall painting, realized with a tempera technique in 1633. Due to its geographical position, the Kvernes church is particularly exposed to weather and consequently maintenance interventions have been carried out in 2015 (Stave Church Preservation Programme) to preserve the building. Previously in 2011 and 2012, 4 data loggers were installed to monitor indoor microclimatic variations basically referable to climatic external conditions, the performance of liturgical functions, and to the presence of visitors (depending on the periods of the year), since none active heating system has never been installed in the church.
In the frame of the international research project SyMBoL (Sustainable Management of Heritage Buildings in a Long-term perspective) such environmental data were elaborated. They represent the firsts internationally published information from long-term monitoring campaigns in stave churches.

Monitoring Deformations of a Wooden Church Tower by Laser Scanning

Scipedia content — Tue, 30 Nov 2021 14:33:06 +0100

Churches are part of heritage structures that take an important role in Europe's cultural identity. As such, these structures must be protected to prevent catastrophic collapse and any damage must be reported timely to establish planning to maintenance and restoration. This can be achievable when the churches are monitored periodically with regular intervals. However, this monitoring strategy has not been available in most of the Europe’s churches for a number of reasons, complexity of the structures and limited budget are just two of them. Laser scanning has been widely used in capturing rich three-dimensional (3D) topographic data of visible surfaces of a structure with high accuracy. This paper presents a methodology to determine the shape and possible deviation from verticality of the church’s tower for monitoring deformation using a terrestrial laser scanner. The 500-year old wooden tower of St. Bavo Church in Haarlem, Netherlands is selected as a case study. First, point clouds of the tower captured from different views are registered into the same coordinate system. Second, a RANSAC method is employed to extract point clouds of a whole façades of the tower. Next, a point and surface-based method is proposed to compute the deformation of the surface from its data points. The results indicate that there is slightly different deformation between the tower facades in the same story and in neighbour stories. Moreover, the maximum total relative deformation at Story 7 of the tower by 0.63m.

Modern Consolidation Methods for Catholic Church in Baroque Style from Arad Fortress, Romania

Scipedia content — Tue, 30 Nov 2021 14:32:57 +0100

This paper presents the results of a study carried on a baroque style Catholic Church, in the field of determining its bearing capacity, restored with reversible materials, technologies and consolidation methods. The Franciscan Monastery is situated in Arad fortress and is an historical building. The structural resistance of the building suffered severe degradation because of the poor maintenance over the years. Two nonlinear analyses were made on the structure that showed that the building may suffer severe structural damage after an earthquake. Based on the results of these analyses some consolidation methods were proposed for the structural elements of the building: walls, arches, vaults, pillars, towers and foundations. Then a third analysis was made using the proposed consolidation methods to determine their efficiency.

Modal and Structural Identification of a Multi-Span Masonry Arch Bridge

Scipedia content — Tue, 30 Nov 2021 14:32:49 +0100

The Olla bridge is a multi-span masonry arch bridge dating back to the second half of the 19th century. The bridge is 117 m long and includes five arches of different spans. Since no original drawings or blueprints of the bridge were found in the archives, the missing information on the geometry of the structure were retrieved through a geomatic survey, whereas the unknown structural details were assumed according to historical handbooks and similar projects. In addition, limited material samples were taken to solve typical uncertainties such as the effective thickness of arches. Subsequently, ambient vibration tests were performed, and different output-only techniques were applied to the acquired time series with the two-fold objective of identifying the dynamic characteristics of the bridge and roughly verifying the invariance of the modal parameters. Finally, all the available information were summarised in a Finite Element model, that – after the updating of uncertain parameters – turned out to be capable of reproducing the identified dynamic characteristics of the structure with a high level of accuracy.

Minimum Thickness and Collapse Conditions of the Irregular Masonry Arch Subject to its Own Weigth

Scipedia content — Tue, 30 Nov 2021 14:32:40 +0100

The present paper aims at assessing the shape irregularities influence on the collapse conditions of masonry arches subjected to vertical point force. Surveys campaigns on cultural Heritage buildings often reveal masonry elements with irregular shapes. In order to accurately predict their actual behavior the presence of such features cannot be neglected. The reasons for these non-canonical shapes are manifold e.g. the evolution of degradation processes and the constructive laws. As a first analysis attempt, the geometrical uncertainties tied to the building work criteria are taken into account. A random parametric model is proposed to generate two-dimensional geometry of irregular polycentric arches. Monte Carlo simulations allows estimating the probabilistic density function of the collapse load multiplier evaluated by means of the implemented limit analysis method. The outcomes referred to the masonry arch with nominal geometry are compared to those obtained for the random polycentric arch, highlighting the extent of the load-bearing capacity reduction due to presence of such shape irregularities.

Methodologic Evolution Assessment of Large Deformations on Romanesque Masonry in Val d‘Aran (XII-XIII centuries), Spain

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

There is a set of Romanesque churches at Val d’Aran that were built between the eleventh and thirteenth centuries. One of the main features of these buildings is the presence of large deformations and geometrical displacements in their masonry. One of the most deformed buildings is the church of Santa Maria de Arties (XII), which arches’ and vaults’ have anti funicular shapes. The assessment is based on a three-dimensional model obtained with a terrestrial laser scanner (TLS). The scanner used is a Leica ScanStation P20. In the study of built heritage, the use of direct measurement techniques for architectural surveying requires a large number of resources. These deformations have caused, in some cases, turn centerlines of the vaults into convex shapes, which have the inverted shape of an arch. Joints appeared because of active and passive thrusts that were performed to keep the structures in equilibrium. Geometrical assessment of the least rigid elements, the pillars, makes it possible to analyze the displacements, which have been the cause of anti-funicular shapes on some vaults. It is possible to deduce the regression plane of the displacements of the pillars of the central nave and to define the deformation vectors over it. Thus, these data all for the directions of the deformations of the vaults to be determined.
The methodology of this study focuses on the assessment of the geometrical characteristics of the pillars, with the objective of studying the displacements that they have suffered. The point cloud is processed with the software; Cyclone, and the program 3DReshaper (2016), and Google SketchUp (2019). The study allows to analyze the evolution of the treatment of points, concluding that deformations of the pillars are not perpendicular to the axis of the central vault. The methodology used and its results let to understand the nature of the displacements in order to preserve these masonry structures.

Mechanical Characterization of Traditional Masonry in an Homogeneous Territory: Valtellina

Scipedia content — Tue, 30 Nov 2021 14:32:23 +0100

The current Italian Building Code provides tables with standard values of the mechanical characteristics of existing masonry. These tables refer to specific typologies, as described, according to masonry texture. As experience suggests, the way in which the masonry is built up could really affect its structural behaviour, both in terms of mechanical properties and failure mechanisms. Furthermore, the code entrusts each Region to improve and better define these mechanical characteristics, specifically in areas where they could be regarded as homogeneous, in order to improve definitions of the quality, the behaviour and the mechanical properties with a higher degree of precision and knowledge.
Valtellina, located in the north of the Lombardy region and in the middle of the Alps, can be regarded as a homogeneous area because of its specific masonry, built up with hard rock stones and weak lime mortar. The available in–situ experimental data about this masonry typology, achieved through MDTs and NDTs, was collected, implemented and improved with additional tests to identify the relevant mechanical properties. This was aimed to classify and structurally identify this specific regional masonry typology, never analysed before.

Mechanical Characterization of Energy Dissipation Devices in Retrofit Solution of Reinforced Concrete Frames Coupled with Solid Wood Panels

Scipedia content — Tue, 30 Nov 2021 14:32:12 +0100

Deep renovation interventions on existing buildings remain currently unattractive due to technical, financial and cultural/social barriers. Now that the European Union 2018 Energy Performance Directive aims to “reach the long-term greenhouse gas emission goal and decarbonize the building stock”, Member States may use their long-term renovation strategies to address risks also related to fire hazards and seismic loads in addition to energy renovation. This opens a wider market for innovative approaches in retrofit of existing buildings.
The current paper illustrates the primary outcomes of an ongoing multidisciplinary Horizon 2020 research project (called e-SAFE), tackling the integration of energy, seismic and architectural renovation interventions through an innovative and combinable technological solution, applicable to non-historic RC framed buildings (i.e. built after 1950) and easily adaptable to specific climatic conditions, seismicity levels and other boundary conditions. Hence, the proposed solution will contribute to the de-carbonization of the EU building stock, reducing the occurrence of natural hazards related to climate changes, and, at the same time, to the improvement of the social resilience against earthquakes and to the enhancement of buildings architectural image.
The seismic retrofit technology consists in the external application of modular prefabricated Cross Laminated Timber (CLT) panels on the existing perimetral walls. These panels are connected to the beams of two consecutive floors by means of friction dampers and provide additional lateral stiffness and strength to the existing structure, thus reducing the storey drift demand in case of earthquake. The friction dampers cut the force transmitted by the CLT panel to the structure and dissipate energy, which further reduce the drift demand. Strength, stiffness and dissipation capacity provided by the system are controlled by modulating the thickness and the number of CLT panels, as well as the friction dampers size.
In this research phase, friction damper prototypes have been designed in order to optimize both mechanical performance and production process. Detailed numerical models allowed to investigate the stress distribution in the dissipative connections. The results of the preliminary testing campaign will be presented and discussed in this paper, also in relation with the findings of the numerical analysis and future tests.

Masonry Walls Strengthened with Vegetal Fabric Reinforced Cementitious Matrix (FRCM) Composites

Scipedia content — Tue, 30 Nov 2021 14:32:04 +0100

Fabric-reinforced cementitious matrices (FCRMs) are promising composite materials for the retrofitting and reinforcement of existing structures. In this study, vegetal meshes consisting of hemp and cotton coated with epoxy were manufactured and combined with a cementitious matrix to strengthen masonry walls. A synthetic glass fibre mesh was also tested. Several walls were manufactured, strengthened, and tested under cyclic loading. The results allow us to compare the performances of different mesh configurations in terms of size and materials. All strengthening solutions significantly increased shear strength capacity and the ability to dissipate energy compared to unreinforced walls. Further, all strengthened walls exhibited multi-track pattern distributions and achieved distortion capacity improvements of up to 300%. Indicators of stiffness, energy dissipation, damping, residual deformation, and damage allow us to compare the strengthening performances of different solutions. The vegetal solutions provided superior efficiency compared to the glass-FRCM strengthened walls. Additionally, the use of a larger volume of vegetal fibres reduces the consumption of cement and can provide a sustainable solution. The main failure mechanism of the vegetal-FCRMs was debonding, which can be remedied by improvements to material interfaces.

Managing Natural Disasters in Historic Areas: a Novel Holistic Seismic Risk Assessment Method Applied to a Relevant Case Study

Scipedia content — Tue, 30 Nov 2021 14:31:55 +0100

The resilience of historic areas is highly threatened by natural sudden onset events such as earthquakes. Major weak points of an urban environment, widely debated in the past literature, concern mainly masonry buildings. However, also the complex urban paths system could be prone to lose its functionality in the aftermath of a seismic event. Urban paths alterations due to earthquake effects can be attributed to extrinsic (i.e.: ruins formation from buildings) and intrinsic (e.g.: ground instability due to landslide or underground cavities) vulnerability; these factors jointly combined with exposure condition of hosted population in urban areas and with the local seismic hazard represent a possible impediment to evacuation process and at the same time, an obstacle to rescuers’ teams occupied in offering a first aid response. Therefore, the work aim is to apply a tool for preliminary evaluation of risk, strictly related to urban paths system considering all abovementioned aspects from a holistic point of view. This goal is achieved by a simplified methodology applicable to a wide-scale on a whole historic centre that takes advantages from a series of easy-to-detect parameters influencing the risk with limited availability of resources. Parameters grouped by topics (i.e.: path use and exposure; geometric features; physical-structural features; extrinsic vulnerability; seismic hazard) are assigned to scores and weights according to a multi-criteria decision-making process generating a numerical index. A typical Italian urban centre made by historical masonry constructions is assumed as a case study to implement the existing method. The detected risk indexes are then graphically provided through risk maps, a chromatic scale indicates which areas are more prone to possible unavailability of paths rather than others. Evacuation planners and emergency managers could embody this tool in their studies to prevent the high number of losses by guiding evacuees toward assembly points through the risk lower paths and to direct risk-reduction interventions punctually where critical condition emerges with different priority levels. Paths accessibility evaluation through a risk characterization could also result useful as a tool for rescuers’ activities optimization and for inhabitant disaster preparedness in terms of being familiar with safest and alternatives paths in emergency conditions.

Macroelement Numerical Simulation of the Seismic Response of a Timber-Retrofitted Masonry Pier

Scipedia content — Tue, 30 Nov 2021 14:31:46 +0100

In the North-East part of The Netherlands, induced seismicity due to gas extraction is affecting a local building stock consisting mainly of unreinforced masonry (URM) houses not designed for earthquake resistance. Experimental and numerical studies conducted at EUCENTRE, Pavia (Italy), have demonstrated that buildings with URM cavity-walls structural systems are among the most vulnerable existing Dutch construction typologies. A light and reversible retrofit system made of timber frames and oriented-strands boards was then designed and tested to increase the in-plane and out-of-plane capacities of masonry piers and to enhance their connections with the floor diaphragms. The development of modelling approaches able to simulate the influence of the retrofit system is of fundamental importance for future applications to real-case existing buildings and for vulnerability studies on different building stocks. Based on two quasi-static in-plane shear-compression tests on two full-scale masonry piers, one in bare and one in retrofitted configuration, a specific macroelement was calibrated to simulate the bare pier lateral response and the effects of the retrofit on the in-plane flexural and shear capacities. This paper discusses the adopted modelling strategies and the comparison between numerical and experimental results.

Lower-Bound Limit Analysis of Masonry Arches with Multiple Failure Sections

Scipedia content — Tue, 30 Nov 2021 14:31:37 +0100

A computational method is proposed for the lower-bound limit analysis of masonry arches with multiple failure sections. Main motivation is the observation that, not only the position, but also the orientation of the failure sections in an arch might not be known in advance in practical applications. The lower-bound limit analysis problem is formulated as a straightforward linear programming problem. Numerical simulations highlight the predicting capabilities of the proposed approach, enabling an accurate and safe prediction of the loading capacity of masonry arches.

Long-Term Structural Health Monitoring of the Fortezza Fortress: Application of Damage Detection Techniques on Existing Cracks

Scipedia content — Tue, 30 Nov 2021 14:31:29 +0100

Structural Health Monitoring (SHM) consists of an elaborated technique, assisting the assessment of existing structures through the detection of active or sudden damages, as well as the diagnosis of possible causes for them. Within the STORM-project [1], the SHM strategy selected for the assessment of the Venetian fortress of Fortezza in Rethymno, Greece was the continuous crack monitoring of four different existing cracks of the structure, due to their relatively large width, located at the Bastion of St. Paul’s, Prophet Elias’ and St. Luke’s as well as the Episcopal mansion.
Besides the crack displacement measurements, several other environmental quantities were monitored at the weather stations, which are known to have a strong influence on the crack width. Considering the fact that most weather fluctuations have reversible effects on structural integrity, it is of great importance to recognize the environmental and operational variation of the structure, and subsequently identify any separate structural change caused by damage [2], [3]. This was achieved by employing a statistical ARX model (Auto-Regressive model with eXogenous input) [4], calibrated for each case after several months. Once this process was completed it was possible to detect possible active damage on the examined structures and estimate possible causes for them.
The successful application of the methodology at the four monitored cracks provided
important information about their state of damage, possible causes and early warnings in
case of hazard. Over the evaluated period, it appears that the bastion of Prophet Elias is in
stable condition, while the bastion of St. Luke and St. Paul are vulnerable to heavy
precipitation. Moreover, the Episcopal mansion showed a destabilization response during the
rainfall period, which is possible to result in the activation of an overturning mechanism.

Landslide Hazard Affecting Historical Buildings: Santa Scolastica Monastery in Subiaco

Scipedia content — Tue, 30 Nov 2021 14:31:20 +0100

Every year landslides occur as a consequence of ground conditions, geomorphological, physical or man-made processes, often triggered by heavy rainfalls or earthquakes. They affect buildings and infrastructures, causing economic and life losses. On the Italian territory, more than 14,000 heritage sites interact with potentially unstable slopes.
This work investigates the effects of a landslide, occurred on the 26th of November 2018, on the Monastry of Santa Scolastica in Subiaco (Rome), one of the most ancient and well-preserved examples of medieval architecture in Central Italy. The geometry of the slope was reconstructed based on aerial photographic survey and point-cloud processing, obtaining meshed surfaces and extracting relevant sections.
The mechanical parameters and the specific hydraulic conditions triggering the failure mechanism were first recognised by traditional limit equilibrium back-analyses and then implemented in a 3D non-linear finite element (FE) model, which included both the slope and the interacting portion of the ancient structure. Elastic-perfectly plastic constitutive assumptions were adopted for the soil, while the structure was modelled by a three-dimensional anisotropic elastic-perfectly plastic constitutive model, specifically conceived for masonry, accounting for block dimensions and staggering joints effects.
Finite element approach proves to be very effective in the analysis of such a coupled interaction problem, leading to a realistic representation of the interplay between the soil displacements and their deformative effects within the structure. The numerical results have been interpreted to highlight the structural response in terms of crack pattern and stress distribution as induced by the interaction with the deforming slope, leading to a quantitative evaluation of the landslide-induced damage. Several scenarios were simulated: first, the pre landslide existing crack pattern was reproduced, then the event was modelled as it occurred, evaluating its consequences on the structure.

Laboratory and In-Situ Characterisation of Masonry Materials in a Large Historical Industrial Building in Barcelona

Scipedia content — Tue, 30 Nov 2021 14:31:10 +0100

This paper presents an experimental campaign carried out in an historical industrial building of Barcelona from the 19th century, considering in-situ and laboratory minor destructive testing (MDT) techniques. The results obtained showed a good relationship between the in-situ MDT techniques and the tests carried out in the laboratory. The experimental results from different portions of the large-scale building allowed the discovery of different material typologies deriving from different construction phases.

Kinematic Approach for Seismic Vulnerability Assessment of Masonry Churches

Scipedia content — Tue, 30 Nov 2021 14:31:01 +0100

The application of reliable predictive methods for the seismic vulnerability assessment of historical buildings represents a challenging issue in the process of risk mitigation at regional/national scale, in order to undertake appropriate strategies aimed at achieving acceptable safety levels. For the application of such policies, the availability of adequate procedures for the correct evaluation of the seismic risk of specific assets, like churches, is a fundamental topic of investigation. In this paper, a simple procedure based on the linear and non-linear kinematic approach is applied to evaluate the seismic capacity of masonry churches, both in terms of spectral acceleration and spectral displacement. To check the reliability of such a procedure, the obtained results have been compared with the damage scenario observed on a population of churches analysed by the research group in the aftermath of the 2009 L’Aquila earthquake.

Iron and Steel Construction Workshops in 19th and early 20th century Belgium: Retrieving their Oeuvre via Trade Catalogues

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

In the 19th and 20th centuries both iron and steel were worldwide applied to construct structures such as halls, markets, stations and bridges. Belgium, an early industrialised country on the European mainland, was famous for its iron and steel production and the export of iron and steel structures. Nevertheless, most early Belgian construction workshops are under explored. Since the company archives of Belgian construction workshops are seldom preserved, trade catalogues are analysed in this paper to get insight in the structures the workshops built. These catalogues offer a broader context for the individual structures that were transported and built worldwide.

Investigation on the Seismic Response of a Large Monumental Complex

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

Historical masonry structures are characterised by a high level of seismic vulnerability, as demonstrated by recent and past seismic events. Monumental buildings, in particular,represent a very challenging topic. Their morphological evolution, characterised by transformations, aggregations and modifications developed over the centuries, have given rise to very complex structures that should be considered as structural aggregates rather than single buildings. The present paper briefly summarises the assessment of the structural performance of the monumental complex of the Certosa di Calci (Italy), by applying an in-depth multi-level and multi-disciplinary approach. The morphological evolution of the aggregate was studied by means of critical historical analysis enabling the identification of the structural units composing it. The complex was, besides, subjected to in-situ survey campaigns allowing an adequate knowledge level. Reliable FEM models were elaborated, and non-linear static pushover analyses were performed. The single structural units were initially studied as isolated buildings and then combined evaluating the influence of the in-aggregate behaviour on the overall structural response. Pushover analyses were performed for each evolution configuration, allowing results in terms of capacity curves, load factors and damage distribution. The methodology presented, although used for a specific case study, can be extended to other constructions characterised by similar complexity and features.

Investigation of the Response of a Masonry Arch Railway Bridge using Membrane Equilibrium Analysis

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

This paper presents an application of Membrane Equilibrium Analysis (MEA) to a historic masonry arch railway bridge in Leeds, United Kingdom. This case study structure is representative of the many masonry arch bridges present on UK and European railway transport networks. It has been chosen because, since 2016, it has been the subject of a detailed Structural Health Monitoring (SHM) campaign, making it an ideal candidate against which to test analytic models. Typically, asset engineers will be responsible for maintaining a large stock of these structures and will lack the time to perform thorough computational analyses. Therefore, simplified approaches, such as MEA, which can offer insight into structural behaviour, have the potential to be highly valuable. This study represents the first step in applying MEA to masonry arch railway bridges.

Investigation of Rubble-Masonry Wall Construction Practice in Latium, Central Italy

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

The 2016-2017 Central Italy seismic sequence severely affected existing unreinforced-masonry constructions in four regions. Those in Latium region proved the most prone to fragmentation because of an unfortunate combination of undressed natural stone units and very low lime content in mortar. Within the framework of a research project funded by the regional government, shake table tests are planned to investigate masonry disintegration as well as possible intervention techniques, as described in a companion paper. All specimens will have natural stone units retrieved from the debris in Collespada, a settlement of the municipality of Accumoli, one of the most affected by the seismic sequence. To push further the representativeness of the specimens with respect to field conditions, wall geometry, masonry fabric and mortar recipe are carefully designed. The wall thickness will be approximately equal to 0.5 m, close to average thickness surveyed in the area. Following the survey of several vertical sections of actual masonry walls, the specimens will present unconnected external leaves with a limited nucleus. Based on tests on mortar sampled from collapsed buildings, mortars will be prepared by a part of natural lime every nine parts of sand. Shear tests on sampled mortar delivered apparent cohesion and friction coefficient that are used as preliminary values of a finite-discrete element model, which can account for masonry fragmentation in dynamic non-linear analyses. The numerical model was tested under the envisioned sequence of records, belonging to the Amatrice station and related to the East component, approximately fault normal, of the two main seismic events, 24 August and 30 October, 2016.

Interdisciplinary Assessment, Analysis and Diagnosis of a Historic Timber Roof Structure From the 20th Century

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

Historic roof structures are complex systems which cannot be assessed individually but need a more holistic approach, in order to understand them as a whole. The great variety of contexts in which the building and its roof were placed, of architectural styles which ultimately influence the shape of the roof but also the diversity of technical solutions used by the craftsman to respond to these needs and its state of conservation, make a multidisciplinary approach necessary.
While 18th and 19th century roof structures from Timisoara, a city from the western part of Romania, proved out to be complex structures which a high value from urban planning, architectural, symbolical and structural point of view, the 20th century is a period of transition with a wide array of influences, mix of styles and technological improvement of the structures.
Therefore, based on the roof structure of the Löffler Palace, built between 1912-1913, placed in the historic centre of the city, the paper tries to highlight that roof structures from this period are also far more than structural systems. Based on a thorough historical analysis and visual inspection of the structure, by using a multidisciplinary assessment procedure [1], the paper shows that 20th century roof structures are closely related to the building they belong, to their context and have a significant philosophical/symbolic and aesthetical value.
At the same time, the procedure also addresses the role of assessment, diagnosis, conservation and maintenance, the structural integrity of the roof, its influence on the seismic behaviour of the historic building, highlighting the connection between the roof, the building and its environment.

Integrated Conservation Strategies in the Netherlands

Scipedia content — Tue, 30 Nov 2021 14:29:59 +0100

In the Netherlands a program for the enhancement of quality in the restoration of monumental buildings is presently carried out, stimulated by national authorities and coordinated by the foundation ERM. Guidelines are issued by the branches involved, from architects to masons, under guidance of an experts’ committee, to perform interventions on monuments and assess them. The aim of this paper is to discuss the contributions to the program offered by different actors active in the field of conservation, the existing synergies and the potential of using a common language and approach. These are needed to facilitate communication and exchange knowledge. The use of the terminology of MDCS (Monument Diagnosis and Conservation System) can help create a community of stakeholders. Sharing the damage terminology and methodology can help achieving a clear and systematic assessment of damage and its causes. It can further improve the communication among all stakeholders, including owners and laymen, stimulating cooperation, and can allow monitoring of damage and interventions.

Inspection, Diagnosis and Modelling of Azurara Church in the North of Portugal

Scipedia content — Tue, 30 Nov 2021 14:29:46 +0100

Santa Maria de Azurara church is a XVI century church in Portugal, classified as a national monument since 1910. The building shows not only the influence of the Manueline architectural style (Portuguese late Gothic style), but also Baroque and Mannerism styles. Presently, the church presents some structural and non-structural problems, so an inspection
and diagnosis of the main building pathologies was carried out. This process was assisted by non-destructive testing (NDT) techniques which included sonic tests, ground penetrating radar (GPR) and Schmidt hammer for masonry elements and Pilodyn and ultrasonic pulse velocity for the timber elements. In addition, scanning electron microscope and x-ray diffraction analysis were used for mortar and stone characterization. Furthermore, dynamic identification tests were performed. Numerical analysis was performed to assess the nonlinear behaviour of the structure under different load conditions. In order to create an accurate model, material properties were estimated from the non-destructive tests and the dynamic properties were used to calibrate the model. A nonlinear static analysis (pushover) considering both vertical and horizontal loading was carried out in order to obtain the maximum load factor for the structure.

In-plane Behaviour of an Iron-Framed Masonry Façade: Comparison between Different Modelling Strategies

Scipedia content — Tue, 30 Nov 2021 14:29:34 +0100

The ‘baraccato’ system is a construction technique with genius earthquake resilient features, used for the reconstruction of the historical city centres in the South of Italy after the catastrophic events occurred in the 18th-19th centuries. A very interesting example of such a building typology is represented by the Church of Santa Maria Maddalena, located in the municipality of Casamicciola Terme of the Ischia Island and built in 1896, after the catastrophic earthquake of 1883. The church is characterized by a mixed ‘baraccato’ system mainly made of yellow tuff block masonry walls strengthened by iron profiles or wooden elements. The reduced damage suffered by the church after the seismic event of 21st August 2017 evidenced the good behaviour of such a mixed structural system, especially into avoiding out-of-plane mechanisms. The presence of the iron-framed system is even more challenging in the definition of the modelling strategies for the structural analysis of the church. Thus, the choice of an appropriate numerical strategy to be used for nonlinear simulation should be properly investigated since the interaction between the frame elements and the elements representing the masonry walls has to be considered. As a first step of the structural analysis of the whole church, the in-plane behaviour of the main façade of the Church of Santa Maria Maddalena is analysed in this paper, with the aim to evaluate the efficacy of different modelling strategies. In particular, the study considers different models according to Finite and Discrete Element strategies available within DIANA FEA [1] and 3DMacro [2] software, respectively. Non-linear static analyses are carried out by means of both software and the obtained results are compared and discussed with the aim of extending them to the study of the whole church.

Influence of Various Light Timber Retrofit Layouts on the Dynamic Response of Typical Duch Masonry Terraced Houses

Scipedia content — Tue, 30 Nov 2021 14:29:23 +0100

A majority of the residential building stock in Groningen (The Netherlands), which has been lately exposed to low intensity ground motions due to gas extraction, consists of unreinforced masonry (URM) structures not originally designed to withstand earthquakes. Amongst them, the terraced house building typology proved to be particularly vulnerable towards horizontal actions. Experimental results from a recently performed shake-table test on a full-scale terraced house prototype, characterised by the presence of a timber retrofitting system, seem to indicate that the dynamic response of these structures might be consistently improved through the employment of such a cost-effective light retrofitting solution. In this work, an advanced discontinuum-based model, implemented in the framework of the Applied Element Method (AEM), is developed to extend experimental results and to numerically investigate the influence of a number of additional timber retrofit layouts, characterised by
different geometrical configurations, on the building behaviour. Each timber component was explicitly represented in the AEM models to represent the possible interaction among URM walls and the retrofitting system. First, the proposed modelling strategy is validated against experimental tests on both non-retrofitted and retrofitted URM panels subjected to cyclic shear compression loading. Then, calibrated mechanical parameters were directly implemented in the full-scale building model. Given the good agreement between numerical and experimental outcomes in terms of both damage evolution and hysteretic response, a comprehensive parametric study was undertaken. Numerical evidence seems to suggest that the employment of different retrofit layouts may have a significant influence on the dynamic behaviour of the selected building typology.

Influence of the Spatial Variability of Joints Characteristics on the Elastic Properties of Masonry

Scipedia content — Tue, 30 Nov 2021 14:29:12 +0100

Brick masonry is a multicomponent composite material, characterized by a marked inhomogeneity, a highly anisotropic behavior arising from the complex interactions between joints and bricks, and a considerable spatial variability of material properties, particularly relevant in the case of historical masonries. The focus of this paper is on the interdependence between the spatial variability of mechanical properties of joints and the overall homogenized response of a given volume element of masonry. It is assumed that mechanical properties of bed joints may vary according to a fixed probability distribution and correlation function and the mechanical response of the volume element is investigated in terms of the overall elastic stiffness. As confirmed by preliminary results, the spatial variability of the mechanical properties may affect the overall response of a masonry wall.

Influence of Temperature on the Structural Behaviour of Masonry Buildings

Scipedia content — Tue, 30 Nov 2021 14:29:02 +0100

This paper investigates the mechanical behaviour of heritage structures subjected to seasonal temperature variations. To this end, the constitutive equation of masonry-like materials, which has been embedded in the finite element code NOSA-ITACA (www.nosaitaca.it), is used to model the static and dynamic behaviour of simple arched masonry structures subjected to thermal loads

Influence of Settlements and Geometrical Imperfections on the Internal Stress State of Masonry Structures

Scipedia content — Tue, 30 Nov 2021 14:28:51 +0100

Since a few decades, the Discrete Element Modelling (DEM) method has been adopted by many authors as a reliable tool for the structural assessment of unreinforced masonry (URM) structures. In this paper, through compas_dem and using 3DEC by Itasca as a solver in the background, we investigate the mechanical behaviour of a three-dimensional URM structure combining the effects of foundation displacements and geometrical imperfections. For this purpose, we consider three different models of the above-mentioned structure. The first one is a perfect digital model, while in the other remaining two models, random geometrical imperfections are applied to the perfect model in order to investigate their influence. After post-processing the 3DEC results, the influence of the applied vertical
settlement and geometrical imperfections is explored in terms of crack pattern/mechanism, internal stress states, and the thrust exerted on the supports. The aim of this paper is not to find the actual stress state of the highly indeterminate structure, but to investigate the role played by the combined effects of foundation displacement and geometrical imperfections on the internal stress state.

Influence of Moisture Content on the Application of ND and MD Tests to Various Species of Timber Elements

Scipedia content — Tue, 30 Nov 2021 14:28:40 +0100

Variations in environmental conditions can affect the structural performance of timber components and constructions. Especially in case of historic masonry buildings, where timber elements can be found either in roof or floor structures, intrinsic defects (e.g., knots, cracks, degradation), as well as the surrounding environmental conditions (e.g., temperature and moisture) can play an important role in the assessment of the mechanical response of the elements. In this connection, non-destructive (ND) and minor-destructive (MD) procedures are used to investigate the onsite conditions of wood, which are commonly based on either tool penetration resistance or wave transmission devices. In the paper, the influence of moisture content (MC) measured with various devices on a series of both old and new timber elements was compared. The elements made of various wood species (mainly red fir, but also white fir, pine and larch) were subjected to laboratory ND and MD testing by three research groups. Results showed the low influence of the MC on MD tests (i.e., resistance drilling and pin penetration) in comparison to the ND (i.e., sonic/ultrasonic) ones. Correlation relationships are provided, which illustrate and approximatively quantify the effect of MC for the experimentally investigated conditions and test equipment.

Inadequate Cases of Intervention in Architectural Heritage Buildings in Mexico after the September 2017 Earthquakes

Scipedia content — Tue, 30 Nov 2021 14:28:32 +0100

The two large-scale earthquakes that occurred on September 7 (Mw 8.2) and 19
(Mw 7.1), 2017 in Mexico left 2,340 damaged architectural heritage buildings throughout the country. Due to the large amount of architectural heritage buildings damaged, the government department responsible for protecting the architectural heritage and the practitioners specialized in conservation was overwhelmed. Therefore, it was necessary to incorporate practitioners who are not specialized in conservation, first to attend the emergency works and later into structural intervention works. In this way, this paper presents some examples of emergency work, as well as intervention proposals that have been inadequate. The common errors observed in emergency works are discussed, as well as the application of erroneous or inadequate concepts in intervention proposals. Comparison with correct intervention works are also presented.

Identification and Assessment of the Seismic Behaviour of Giotto‘s Bell Tower in Florence (Italy)

Scipedia content — Tue, 30 Nov 2021 14:28:22 +0100

Among the different typologies of historic buildings, masonry towers represent a hallmark of many European town centres which embody an important heritage to be preserved and passing on to future generations. Giotto’s Bell Tower in Florence together with the Leaning Tower of Pisa and the San Marco Tower in Venice (which collapsed in 1902) is one of the iconic masonry towers ever built in Italy. The assessment of the structural behaviour of these structures, together with the development of proper preservation strategies, has attracted in recent decades the interest of a plethora of scholars. Most of the studies on towers vulnerability focuses on the assessment of their seismic behaviour, since their slenderness exposes them to the dynamic effects induced by medium-to-severe earthquakes. This paper, given this background, discusses the identification and the seismic behaviour of Giotto’s Bell Tower in Florence. In a first part of this paper a refined numerical model, built through the finite element technique based on a recent laser scanning survey, is reported together with the procedure adopted for its modal identification. The finite element model accounts for the soil-structure-interaction. In a second part of this paper the numerical model is employed to perform linear time-history analyses, by using natural accelerograms. The results of the analyses allow to assess the seismic behaviour of the Bell Tower of Giotto and suggest preservation strategies.

Holistic Approach to Cleaning and Protection of Stone Façades of 20th Century Architectural Heritage

Scipedia content — Tue, 30 Nov 2021 14:28:12 +0100

Modern urban areas represent our recent past with great aesthetic and heritage value which should be maintained and preserved for the future. One of the best recognized landmarks of the city of Novi Sad, capital of Vojvodina region positioned in northern Serbia, is the architectural masterpiece Banovina Palace in which today resides provincial government. It is an elongated, closed, horseshoe-shaped structure, built in late 1930s in a modern style and influenced by expressionist architecture. Two-floor high with a tower on one end the building dominates the scenery and symbolizes the appearance of a large ship on the Danube River which flows in the immediate vicinity.
The façade of this famous building is covered with white marble from Adriatic island of Brac. After almost 80 years of exposure to weathering, urban pollution and manmade devastation, the façade was in need of cleaning, consolidation and protection. In the attempt to prepare for the European Capital of Culture 2021, the City of Novi Sad started ambitious project of local heritage revival. Due to awareness of lack of understanding about stone nature and behaviour, stone cleaning and protection usually raises concerns and cautious. The Laboratory for Materials in Cultural Heritage, Faculty of Technology, was invited to join the project to preform holistic characterisation of the stone, reveal deterioration mechanisms, and propose conservation methodology.
Using mobile laboratory with non-destructive techniques coupled with laboratory testing, the stone façade was comprehensively analysed. Various deterioration patterns were identified including patina, dirt deposits, eroding surfaces, yellow layers and black crusts, large amounts of carbonaceous particles responsible for black appearance of stone surface, soluble salts, microbiological corrosion, residue of inadequate graffiti removal, façade paints, acrylic binders, as well as mechanical damage of stone panels. Based on laboratory testing of a number of cleaning, consolidation and protection techniques and products, the most promising ones were also tested in situ [1]. Products ranging from traditional conservation approaches to innovative solutions like self-cleaning photocatalytic coating as final protective layer, were selected [2]. Resulting from research the methodology for cleaning, consolidation and protection was established in 2017 and implemented in 2019, where the laboratory acted again as scientific supervision and control of the conservation works. The presented approach allowed deep understanding of the complex problem and guaranteed responsible conservation strategy; therefore it stands as an example of 20th century architectural heritage preservation.

Historical Timber Structures in Adana-Tepebağ Settlement and Consolidation Approach with Modern Timber Prefabricated Systems

Scipedia content — Tue, 30 Nov 2021 14:28:04 +0100

Adana-Tepebağ settlement is located in the south-east part of the Anatolia close to
the Mediterranean Sea. This settlement is located in the center of the city, composed of unique
architectural heritage with different plan typologies of historical structures, used of varied
materials such as timber, brick, and stone. Traditional timber structural systems are widely
used in this area.
In this research, proposing a consolidation method for traditional timber structures with
modern prefabricated systems in the frame of technological prefabrication criteria. Such as
several joint details, lifting and storage properties, and fabrication state of the construction
element and minimum waste ideal of the timber material [2].
This research is done in a historical settlement in Adana-Tepebağ. The state of the timber
structures is in a high damaged condition as a result of the lack of maintenance in an extended
period. Consequently, there is a need for a consolidation method for the maintenance of
historical structures in that area. These analyzing criteria are applied to a historical timber
structure in that settlement on a case study for showing the progress of this methodological
approach.
The progress of the methodology is composed of three main steps;
1-The damage and corrosion analysis of skeleton timber structure.
2-The decision method within the frame of technological prefabrication criteria of modern
timber prefabricated elements on the damaged parts of this structure.
3-Data’s, which are collected from the previous two stages, are analyzed and compared.
This methodological approach expected to be a rational decision method for the consolidation
of historical structures in the Tepebağ settlement. Significantly partly damaged timber
structures consolidation is very critical in the frame of budget and the authenticity of the
building.

Historical and Typological Characterization of Churches in the Historical Centre of Cusco, Peru

Scipedia content — Tue, 30 Nov 2021 14:27:52 +0100

UNESCO declared Cusco a historical site due to the importance of its constructions and traditions. However, Cusco lies on an active tectonic area with several plate faults and thus, is prone to endure seismic activity. The 1650 and 1950 earthquakes had devastating consequences on churches, with collapses of bell towers, roofs and vertical walls. After these earthquakes, the churches became more complex because of reinforcement and diverse structural changes introduced. Therefore, it is necessary to understand their current static and dynamic behaviour. In addition, it is fundamental to establish control measures to preserve churches and to guarantee safety of the hosted people, as well as to protect the artistic, architectural and cultural treasures they contain. The first step, however, is to survey the churches and to fully identify their structural features. This article presents a description of the architectural and structural typologies of the churches in the historic centre of Cusco and its relation to the most common failure mechanisms experienced by churches during earthquakes. To this end, this research carefully recreates typologies, geometry, materials and interventions carried on over centuries on these churches. It contributes to the seismic vulnerability knowledge of the studied churches and gives conclusions for decision-makers in future resilience plans.

Historical Analysis and In-Situ Inspections of a Cultural Heritage Masonry Building

Scipedia content — Tue, 30 Nov 2021 14:27:43 +0100

Recent seismic events that hit the Centre Italy have highlighted the high vulnerability of the historical and architectonical heritage that is the richness of the country, pointing out once again the difficulty of the assessment of monumental buildings such as churches or historical palaces, due to their uniqueness, the absence of a design, the limitation of invasive in situ tests, but the importance of the knowledge to understand the seismic behavior more than the static analysis under the gravitational loads. In the present paper the knowledge procedure is framed considering the case study of an important nineteenth century astronomical observatory, constructed in 1816-1819. The building, located in Naples, in the southern of Italy, classified by the Italian code as an area of medium seismic hazard, is analyzed by the use of integrated investigation activities such as coring, flat jack tests, georadar to obtain all the information due to the variability of the materials and the influence of previous alterations and repairs, that are data all necessary to develop a reliable model.

Health Monitoring Tests of Heritage Structures: Application of MEMS Accelerometers to Two Multi Tier Pagodas

Scipedia content — Tue, 30 Nov 2021 14:27:36 +0100

The paper introduces a health monitoring system based on MEMS (micro electromechanical systems) accelerometers. The used MEMS accelerometers were recently developed by one of the authors. They excel in cost efficiency, calibration accuracy and robustness. The health monitoring system was installed in two multi-tiered pagodas. They were a two-tiered pagoda, Pashupatinath temple and a five-tiered pagoda, Nyatapola temple for four months. Both pagodas are located in Nepal. In both cases, a number of earthquakes were captured by the installed accelerometers, as it permitted estimation of the fundamental mode of the tested pagodas. The paper deals with two tasks. The first task introduces the used MEMS accelerometers. The features of the accelerometers are discussed. The second task discusses the dynamic behaviour of the pagodas identified by the installed monitoring system. The paper presents adequacy of the developed MEMS accelerometers for health monitoring test of heritage structures.

Geotechnical Structures in the Ancient World. The Case of the Ziggurat of Ur in Mesopotamia

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

The current study presents several geotechnical structures which were built during the antiquity, aiming to illustrate the ancient technological achievements and to provide an insight into the geotechnical skills in the past. It is evident that ancient civilizations had awareness of the various geological and climatological / meteorological hazards (i.e. natural hazards) that affected the structures and used rather reliable techniques for that time. Furthermore, the study aims to illustrate how some of these are related to modern geotechnical structures. More specifically, the earth retaining techniques used for the construction of the massive pyramid-like structures Ziggurats are shown, highlighting their contribution to structural safety. In this framework, several numerical models have been built and analysed, using the Bishop Analysis for slope stability method and the Finite Element Stress Analysis Method. The results of the numerical simulations are presented and discussed.

Geometric and Structural Information for the Analysis of Historical Domes: The Case of the SS. Trinità Church in Torino

Scipedia content — Tue, 30 Nov 2021 14:27:18 +0100

Investigation into the geometric configuration of historical masonry domes isfundamental when studying the structural behaviour of these architectural elements, above all if they have historical and artistic relevance. Indeed, accurate geometric information is essential also for the construction of reliable mechanical models, to monitor the condition stateof the building and to plan strengthening and conservation interventions. To this aim, a multidisciplinary approach is required to collate the highest possible amount of data useful for the numerical modelling, including historical and archival research.
The "SS. Trinità" church is a 16th century building of great historical, architectural and structural significance in the historic centre of Turin. It owes its fame primarily to the architect who built it, Ascanio Vitozzi, and to its large dome, built after the architect’s death. The availability of a recently undertaken laser scanner survey of the intrados of the dome made it possible to detect several depressions of the masonry cap. These findings can be either due to construction defects, or to structural problems that developed over centuries, or to the severefire which struck the dome in 1942.
In this multidisciplinary research, different numerical models of the masonry dome of SS.Trinità church were built. As a first step, a geometric study was based on the point cloud from the laser scanning. Then, structural analyses were conducted on the two different models of the dome-tambour system of the building, in order to try to explain the observed deformation behaviour.

General Thrust Surface of the Masonry Domes

Scipedia content — Tue, 30 Nov 2021 14:27:10 +0100

Masonry domes are shell-like structures with a no-tension type material behavior [1]. The dome geometry, material behavior and the type of the loading define how the dome balances the load. It is known and proved that the dome could balance the load only by forces, without bending moment but cracks may appear since the material does not resist tension. The surface where the balancing forces are acting is called the thrust surface. The paper introduces the idea of the general thrust surface. It is such a balancing surface where the forces are not acting in the tangent plane of the thrust surface and otherwise it is moment free. A method is shown how to find the general thrust surface for a cracked spherical masonry dome. Numerical example illustrates the usefulness and effectiveness of the proposed method to determine the general thrust surface of a spherical dome when radial stereotomy is considered. By the help of the proposed model the safety of the more than 350 years old, cracked dome of Gol Gumbaz, India can be proofed.

Gaudí, a New Architectural Concept of Maximum Structural Efficiency: Catenary Vaults, Complex Ruled Surfaces, Branched Pillars and an Endless Innovative Strategies

Scipedia content — Tue, 30 Nov 2021 14:27:02 +0100

For the first time in the history of architecture, Antonio Gaudí used structural elements based on complex ruled surfaces – beyond traditional conical or cylindrical surfaces –, catenary vaults or branched pillars, in order to increase the structural efficiency of his buildings. The catenary arch had been used only in the construction of bridges by a few engineers, starting in the 18th century. Arata Isozaki said that the “scale model and the structural analysis of the church at the Güell Colony are the most original in the history of architecture”. Beyond his artistic and creative genius – which has now been widely studied and acknowledged – Gaudí was a revolutionary architect, whose experimental approaches to the design and calculation of structures implied a focus that was so far ahead of its time that later, hugely significant engineers and architects have coincided with the methods and
systems used by Gaudí half a century earlier. Norman Foster said in reference to Gaudí: “his methods, a century later, are still revolutionary”.

From the Cure of the Simple Structural Analysis to the Control of the Final Technological Quality - The Conservation of "Santa Maria Degli Angeli Orphanage" in Castelgrande (Potenza, Italy)

Scipedia content — Tue, 30 Nov 2021 14:26:53 +0100

The conservation work carried out on the “Santa Maria degli Angeli” Orphanage in Castelgrande (Potenza, Italy) following the earthquakes of 1980 and 1981 is a good example of the need to evolve and refine the concept of seismic consolidation and upgrade of monumental heritage; this, considering not only the needs of the current structural calculation, but also those related to the design of durability and overall technological quality. Built from 1878 around the original nucleus of a chapel, the seminary, then an orphanage, kindergarten, nursery school, sewing workshop and school, and summer mountain colony, constitute a precise landmark in the landscape of the ancient town of Castelgrande. Severely damaged by the earthquakes, it was declared unfit for use and evicted, and is still abandoned today.Immediately afterwards, radical refurbishment works were carried out on it, with the creation of sub-foundations, injections and tackles with reinforced concrete slabs for the load-bearing walls, replacement of the floors in steel beams and bricks with reinforced concrete floors, replacement of the wooden roofs with others of the same configuration, but in steel beams and clay tables, with a reinforced concrete slab above. The workings were not completed due to lack of funds and those performed so far show today serious pathologies (in particular the corrosion of the reinforcement of the joist of the floors and of the steel beams) as result of the lack of attention to fundamentals of materials science and of durability. Based on the current legislation and calculation methods, the research verified the seismic vulnerability of the building and proposed the necessary corrective actions: in particular, the replacement of the roofs with others, lighter and more durable, made of laminated, conditioned local Quercus cerris wood. A new destination has been proposed, linked to the presence of the Astronomical Observatory, and its upgrade to nZEB has been designed, in respect of its monumental features.

From Reality to Point Clouds. Survey and Analysis of Sant Miquel Church of Batea (Spain)

Scipedia content — Tue, 30 Nov 2021 14:26:44 +0100

Current massive data capture techniques (MDCT), such as terrestrial laser scanning and digital photogrammetry, have become widespread during the last decade, and raises the possibility of developing new assessment methodologies based on the 3D documentation. The paper exposes de results of using simple, non-invasive procedures for the assessment of the shape of a masonry building from a point clouds registered with a terrestrial laser scanner. The case study selected is the church of Sant Miquel of Batea (eighteenth century), located in the province of Tarragona (Spain). The methodology used combines 2D and 3D processes for assessment of the geometry. The results of the investigation have confirmed the good condition of the building. It presents dimensional variations, most of which can be related to the construction process, while some displacements identified provide information about the accommodation process of the masonry structure.

From Art to Science of Construction: the Permanence of Proportional Rules in the “Strange Case” of the 19th Century Ponte Taro Bridge (Parma, Italy)

Scipedia content — Tue, 30 Nov 2021 14:26:34 +0100

The bridge commissioned by Maria Luigia to Eng. Antonio Cocconcelli and built between 1816 and 1821 over the Taro River (near Parma, Northern Italy), is a very important monument, both from a cultural and strategic point of view. This 20 arches masonry bridge reaches the length of nearly 600 meters and constitutes a very interesting case study, not only for the technical and structural issues related to its restoration and use (with increased traffic loads) but also for the role that geometry played in its history and stability. In this paper, a compared analysis on the historical ‘proportional theory’ and the constructive features of this ancient bridge is proposed with the final aim to show the importance of recovering “empiricism” in dealing with ancient monuments. Thanks to a high precision survey the realized structure has been compared to the original project, in order to detect the deformations suffered by the structure in time, thus applying the “historical monitoring” procedure to the monument. Hence, starting from the dimensional theory, a static analysis of the bridge is proposed by means of Mery’s graphic method, in order to investigate the structural safety level of the original project, also considering the current load conditions. A comparison with the static results obtained by means of limit analysis, finally shows the validity of ancient proportional theory, which can constitute a first qualitative method for structural validation of ancient masonry structures.

Foundation Development from 1890-1942 for Long Span and High Rise Buildings at Mexico City

Scipedia content — Tue, 30 Nov 2021 14:26:25 +0100

The subsoil of Mexico City, Mexico, has had a complex behavior; filled with light flocculent structure and layers at different depths of stiff material, producing regional and local differential settlements and liquefaction being a seismic zone. Long Span and High Rise buildings in this City have been a challenge to construct, being its foundation solution, one of the essential elements for its success. This study aims to present the evolution of the long span and skyscraper in Mexico City, being the foundation solution a crucial issue for this new construction era. The foundation solution of five iconic buildings built during this periodanalyzed by their designers and authors of this paper is presented. Each foundation solution is evaluated considering today's advance in Mexican soil mechanics, arriving at the solution most used nowadays in the city for this kind of buildings.

Flexural Resistance of Masonry Wall Retrofitted with Timber Panel under Out-Of-Plane Loading

Scipedia content — Tue, 30 Nov 2021 14:26:17 +0100

Retrofit of unreinforced masonry (URM) structures is incessantly attracting interests of masonry professionals. Because there are enormous URM structure stocks in different parts of the world that have shown vulnerability to damage against out-of-plane actions due to having limited flexural strength and deformation capacity [1]. As such, there is a global trend of promoting the development of sustainable retrofit techniques for URM structures. The authors' previous study [2] has introduced the application of oriented strand board type 3 (OSB/3) as a prospective sustainable retrofit material for URM wall with evidence of improving the flexural performances. This paper presents, for the first time,experimental works on 1115 x 1115 x 215 mm double wythe single leaf URM walls. Specifically, quasi-static out-of-plane loading tests were carried out on two plain specimens, two single-sided retrofitted walls and two double-sided retrofitted walls. The flexural and displacement capacities were evaluated in both plain and retrofitted specimens, and the results substantiated that OSB/3 application improves the flexural capacity of masonry wall. Therefore, the application of OSB/3 for retrofitting URM buildings can be considered as an inexpensive, efficient and sustainable retrofit technique.

First Reinforced Concrete Building in Rijeka Port - Ferenc Pfaff‘s Warehouse No.17

Scipedia content — Tue, 30 Nov 2021 14:26:09 +0100

This paper will explore an early reinforced concrete warehouse, constructed from 1906 till 1909, which is the most impressive warehouse in Rijeka Port – with ground floor dimensions equal to 45x100 m, consisting of a basement, high ground floor and three storeys, designed to sustain 15 kN/m2 floor loading. This warehouse is the first building in Rijeka Port constructed entirely as a reinforced concrete structure and demonstrates significant technical achievements, which have not been sufficiently valorised so far. Besides obtaining information about the structural design of early reinforced concrete structures special attention will be given to better understanding of early 20th century construction techniques and particularly to reinforcement detailing, since original plans and construction drawings with detailed information about the reinforcement have been preserved.

Fire Prevention in Ottoman and Habsburg Building Codes for Bosnia and their Application in Travnik

Scipedia content — Tue, 30 Nov 2021 14:25:59 +0100

The city of Travnik, located in central Bosnia, served as an administrative center of the Ottoman province between 1699 and 1851, with only short interruptions. In 1878, the Congress of Berlin awarded the Austro-Hungarian Monarchy rights of occupation for this Ottoman province. The following year, the new administration already faced its first big fire, which wiped out a major part of downtown Sarajevo. A new building code, which tried to minimize future hazard risks and was soon valid for all of Bosnia, was established in 1880.
In September 1903, two major fires hit Travnik. The Ottoman administrative building used by the
new officials was already fire-improved, so it survived the fires without sustaining any serious dam age. The same cannot be said for the traditional residential neighborhoods at the foot of Travnik castle, which burnt down to their foundations. The mosques in Travnik that were constructed mostly of wood were damaged severely. Austro-Hungarian administration officials identified the traditional way of building as a serious risk for all of Bosnia and tried to counterbalance by implementing the new regulations rigidly in their post-fire reconstruction program. They seem to have developed a more secure ‘mosque building model type’, which they implemented in the re-erection of the Lončarica, Zulići, Kahvica and Šumećka mosques. While rebuilding the Varoška and Lukačka mosques, the distinct ‘official’ style of Habsburg-Bosnia [1], a blend of various architectural ele ments associated with ‘the Orient’ that the literature tends to name ‘pseudo-Moorish’, was used.

Fill-in-Glass Restoration: Exploring Issues of Compatibility for the Case of Schaesberg Castle

Scipedia content — Tue, 30 Nov 2021 14:25:49 +0100

This paper explores a novel restoration approach for consolidating historic structures using structural glass to substitute for the missing elements, preserving at the same time the structural integrity of the structure. A restoration design is proposed for thehypothetical consolidation of the remaining tower of Schaesberg Castle, in Limburg, The Netherlands. The masonry walls suffer from a significant loss of material and a temporary steel structure currently prevents the tower from collapsing. It is proposed to use stacked float glass to fill the missing parts of the wall. The connection between the old masonry and new glass is the most challenging aspect given the different physical and mechanical properties of the materials, which need to work together in a coherent way. Shear tests of various connecting
materials are carried out in order to evaluate the performance of this connection with respect to aspects of compatibility and feasibility.

Fibre Reinforced Geopolymers as Inorganic Strengthening Composites for Masonry Structures

Scipedia content — Tue, 30 Nov 2021 14:25:39 +0100

The study presents an assessment of externally bonded Fibre-Reinforced GeoPolymers (FRGPs) as strengthening material for masonry structures. Thanks to their tailored chemical and mechanical characteristics, geopolymer matrices can fulfil the restoration criteria for Built Heritage (BH) with the benefit of heat-resistant performances better than those of organic and inorganic matrices used in Externally Bonded Fibre Reinforced Polymers (EB-FRP) and Fabric-Reinforced Cementitious Matrix (FRCM) materials, respectively. This work is built on the outcomes of a previous investigation that proved the suitability of the developed geopolymer matrix for applications on clay bricks, revealing a good adhesion to masonry substrates and to embedded reinforcements. The behaviour of three FRGPs, including either a bi-directional basalt mesh, a bi-directional carbon mesh or a unidirectional Ultra High Strength Steel (UHSS) fabric, was explored by means of local tests on masonry sub-assemblages made of soft-mud clay bricks and hydraulic lime mortar. In overall, 9 single-lap shear tests on single bricks with a bonded length of 200 mm and 9 three-point bending tests on 2-brick slices, connected by a mortar joint and reinforced at the bottom face, were carried out. Lastly, the behaviour in alkaline environments of each reinforcement was investigated through tensile tests on coupons immersed for 28 days in alkaline solutions simulating the conditions of the geopolimeric
matrices. Results confirmed the interesting potential of FRGPs for strengthening masonry elements, highlighting a good performance of steel and carbon reinforcements. On the other hand, precautions should be taken with basalt meshes that, as expected, were more sensitive to alkaline environments.

Fatigue Assessment of Old Riveted Railway Bridges: Laboratory Testing of a Real Bridge

Scipedia content — Tue, 30 Nov 2021 14:25:29 +0100

The bridge over the Quisi Ravine in Alicante Province (Spain), built between 1913
and 1915, consists of six 22-22-42-42-22-22 m long steel Pratt truss spans, the lateral
spans being isostatic and the central spans continuous. All the joints between the steel
elements are riveted. As the bridge has been carrying railway traffic for more than 100
years, its condition needed to be assessed before carrying out the necessary repairs reinforcement to extend its service life. One of the most interesting tasks on the bridge
involved a study of its fatigue behaviour to estimate its remaining useful life. Only a few
kilometres away there happened to be another bridge with identical geometry over the
Ferrandet Ravine, which had recently been dismantled and taken out of service and had
carried the same railway traffic as the one over the Quisi Ravine. Advantage was therefore
taken of this unique opportunity to test one of its isostatic spans in order to extrapolate the
results to the Quisi Bridge. These tests were carried out at the ICITECH laboratories at the
Universitat Politècnica de València in two different scenarios: 1) one test on a 22 m span,
and 2) another on one of its girders, in both of which simulated railway traffic cyclical
loads were applied. The results allowed us to estimate the number of trains that could
pass over the bridge and its remaining service life, and also to define a monitoring
method to help in decision making in case of possible failures of its component parts.
The study also included an analysis of the bridge’s robustness in local failures of some
of its elements, which led to a further bridge cyclical loading test with a deliberately
damaged component. Even though other researchers had previously carried out fatigue
tests on full-scale riveted bridge elements, the ICITECH study is unique in that it is the
first time a full-scale bridge has been subjected to fatigue tests. This work was
accompanied by advanced numerical modelling studies considering the fracture
mechanics theory.

Fast Seismic Vulnerability Evaluation of Historical Masonry Aggregates through Local Analyses: an Adaptive NURBS-based Limit Analysis Approach

Scipedia content — Tue, 30 Nov 2021 14:25:19 +0100

An efficient computational tool for the local failures analysis in historical masonry
aggregates is proposed. A NURBS (Non-Uniform Rational B-Spline) representation of
geometry is adopted. NURBS entities, which are common in commercial CAD packages, have
the great advantage to describe complex geometries (such as curved elements and walls with a
high number of holes) with very few elements. An upper bound limit analysis formulation is
implemented, in which the adopted NURBS elements are idealized as rigid bodies with
dissipation allowed only along interfaces. The mesh of NURBS elements is progressively
adjusted through a genetic algorithm in order to minimize the live load multiplier. This
procedure is applied in the evaluation of the horizontal load multiplier associated with the
activation of local mechanisms during a seismic event. Some case studies, referring to masonry
aggregates located in the historical centers of Arsita (Abruzzo region, Italy) and Sora (Lazio
region, Italy), are here presented. A quick evaluation of the seismic vulnerability is performed
through the presented NURBS-based computational tool, showing the high importance of the
local response in the study of the seismic behavior of masonry aggregates.

Extrados Strengthening of Single-Leaf Vaults Against Seismic Actions

Scipedia content — Tue, 30 Nov 2021 14:25:10 +0100

Single-leaf vaults are acknowledged among the most vulnerable components of historical masonry constructions with respect to earthquake loads, particularly when featuring large span to thickness ratios, as in the case of single leaf covering the main nave of churches. These elements often require structural strengthening against seismic actions. In this paper, two different extradostechniques are tested: lightweight plywood restraining elements and FRP laminates embedded in a lime mortar layer. The techniques are tested on single leaf vaults having a very unfavorable span to thickness ratio.
A previous study on less slender vaults, showed that lightweight plywood centerings, applying passive confinement to the vault extrados, inhibit the onset of the typical four-hinges failure mechanism. This lightweight, dry solution can be easily prefabricated, transferred and assembled at the construction site. The technique is reversible and fully compliant with the major preservation principles. FRP is also effective against the onset of the failure mechanism but entails larger deformations of the retrofitted vault, which may be detrimental in the case of possible decorations. The solution requires special man labor to ensure correct smoothening and cleaning of the vault extrados and to trigger effective bond between the mortar and the vault extrados. Both solutions are shown to enable small relative displacements of the vault springing, which may follow the deformation of possible internal ties.
The effectiveness of these retrofit techniques was comparatively verified through experimental tests on single-leaf barrel vault stripes at 1:2 scale subjected to cyclic distributed unsymmetrical loads and through comparison with the seismic response of a reference unreinforced single-leaf vault.

Experimental Tests on FRCM and FE Modelling for the Heritage Structure‘s Reuse

Scipedia content — Tue, 30 Nov 2021 14:25:02 +0100

This paper presents the first results of an ongoing research in partnership with Kimia
S.p.A. company (Italy). In particular, experimental tests on masonry specimens reinforced with
Fiber Reinforced Cementitious Matrix (FRCM) have been recently conducted by Kimia
according to the up-to date guidelines: specifically the single-lap shear test. On the base of the
experimental results, a finite element model has been developed in order to reproduce the
actual behaviour of the specimens. The results, derived both by the experimental tests and the
FE model calibration, constitute the basis for planning an experimental campaign on masonry
walls strengthened by FRCM loaded in the plane. The constructive details of the experimental
set-up, conceived in order to create a self-balanced system and to bring the specimens to
failure, are described together with a preliminary numerical modeling based on the already
done test.

Experimental Testing of Two Novel Stress Sensors for SHM of Masonry Structures

Scipedia content — Tue, 30 Nov 2021 14:24:51 +0100

The paper presents an experimental study on the performance of two types of
stress sensor for their possible use in structural health monitoring (SHM) of masonry
constructions. Ceramic piezoelectric sensors and capacitive sensors were installed in mortar
bed-joints of two series of masonry specimens made of calcarenite stones and clay bricks. The
specimens were tested under uniaxial compression, assessing the effectiveness of the sensors in
recording the stress state variation in terms of vertical stresses within different types of
masonry. Experimental results show that, although both the ceramic and capacitive sensors
were initially designed to be embedded in concrete elements, their application in mortar joints
ensures a good agreement with records by standard measurement devices. Results also
demonstrate the possibility to extend the application of these devices to existing masonry
structures, where SHM becomes a challenging issue.

Experimental Study on the Shear Behavior of FRCM Strengthened Masonry Panels

Scipedia content — Tue, 30 Nov 2021 14:24:43 +0100

nnovative strengthening solutions, such as Fiber Reinforced Cementitious
Matrix (FRCM), are becoming increasingly diffused for the retrofitting of existing masonry
structures with the aim of reducing the seismic vulnerability of these construction
typologies. In recent years, many studies have demonstrated the suitability of these materials
in enhancing the shear capacity of masonry walls and improve the overall structural behavior,
avoiding fragile collapse mechanisms. In the present work, six diagonal compression
tests were performed on unstrengthened and FRCM strengthened masonry panels to
evaluate the improvements attributable to the presence of the FRCM systems. Two different
bidirectional basalt grids were applied to the masonry samples, with and without mechanical
anchorages. The tensile and bond properties of the chosen FRCM systems were
investigated through laboratory tests. The objective was, indeed, to compare the
performances of two textiles, characterized by different densities, and to investigate the
role of mechanical anchorages. The experimental results confirmed the efficiency of the
FRCM strengthening systems in improving the shear behavior of masonry panels. The
FRCM strengthened samples experienced a considerable strength increase and less brittle
failure mechanisms. The roles of both the mortar matrix, the fiber grids and the mechanical
anchorages were highlighted by analyzing the onset of cracking and the failure propagation
within the samples.

Experimental Investigation on the Torsion-Shear Behaviour at the Interfaces of Interlocking Masonry Block Assemblages

Scipedia content — Tue, 30 Nov 2021 14:24:35 +0100

This paper presents an experimental investigation on the initial shear (cohesion)
and torsion-shear strengths at the interface of an interlocking masonry block. An interlocking
block is a rigid unit with locks avoiding the block to slide. This improves the seismic response
of dry jointed assemblages of masonry structures subjected to in-plane and out-of-plane
loading. The experimental investigation is designed and carried out for the corrugated
interface having one lock with rectangular cross section, i.e. the specimen is an interlocking
unit composed of a main body and a lock located on the upper face of the main body. Cement-
based mortars are selected to reproduce the specimen, casted using a mould provided by a
3D printer, and both the lock and the main body are kept rigid during the tests. The initial
shear and torsion-shear capacities of the interface at which the lock is connected to the main
body are assessed together with its quasi-brittle fracture and registered in terms of load-
displacement curves. In the designed setup, the horizontal force is applied to the rigid lock
until it is disjointed from the rigid main body of the block, while the effect of rocking during
the shear test is avoided. The force and the displacements are measured using a load cell and
Linear Variable Displacement Transducers (LVDTs), respectively. The experimental
programme includes four different sets with different load application points and different
load directions, each set repeated on a number of similar specimens. Empirical formulations
between the initial shear and compressive strengths of the lock interface are also evaluated.

Experimental Investigation of the Bond between Glass Textile Reinforced Mortar (GTRM) and Masonry Substrate: the Effect of Textile Impregnation

Scipedia content — Tue, 30 Nov 2021 14:24:27 +0100

Textile Reinforced Mortar (TRM) is an appealing choice for the strengthening of
existing structures and especially that of monumental character through application as
external reinforcement. In the current study, the TRM-to-masonry bond was experimentally
investigated focusing on the parameter of the yarns’ treatment, that is none or impregnation
with Styrene-Butadiene Rubber – SBR latex. For this purpose, both double-lap/double-prism
(DL) and single-lap/single-prism (SL) shear bond test configurations have been employed.
Specimens comprised strips of glass fiber textiles (either uncoated – UT or fully impregnated
– IT) applied on wall prisms of stack-bonded smooth clay units through a cement-based
mortar. TRM strips of DL specimens (with uncoated textile – UT or impregnated textile – IT)
had a bond length (BL) equal to 150 mm. This BL was larger than the effective one, i.e. the
minimum length needed for the attainment of the maximum TRM bond capacity (with UT).
Due to the inadequacy of the DL set-up in capturing specimens’ post-peak response, the SL
set-up was also opted for. TRM strips of SL specimens (with UT or IT) had various BLs (100
mm, 150 mm and 200 mm) in order to study the combined effect of BL and textile
impregnation. According to the results from both set-ups, the maximum bond load, Fmax of
specimens with IT was increased by 40% in comparison with specimens with UT.
Additionally, Fmax of specimens with IT increased with increasing BL.

Experimental Investigation of Scarf Joint of ‘Lightning Sign’ in Bending

Scipedia content — Tue, 30 Nov 2021 14:24:19 +0100

The paper presents a description and results of the research concerning one of the
scarf joints, so-called ‘lightning sign’ (also described as ‘Bolt of lightning’ or ‘Trait-de-
Jupiter’). This joint has been used and can be commonly found in wooden historical structures
and is considered to be an interesting example of carpentry longitudinal joints. In the
experimental part timber beams with this type of joint shaped in the different planes, horizontal
and vertical, reinforced with spindle fasteners (metal bolts), were subjected to four-point
bending tests. As a result, the static equilibrium paths and the bending capacities of individual
beams were obtained. They were compared to the load-bearing capacity of the continuous
reference beam. Moreover, a simplified numerical analysis based on FEM was carried out for
comparison the rigidity of individual beams. A comparison of the results for series of beams is
discussed and some conclusions and possible directions of the future actions in the subject are
presented.

Experimental Data for the Calibration of a Non-Linear Numerical Model for Describing the Response of Masonry Constructions under Cyclic Loading

Scipedia content — Tue, 30 Nov 2021 14:24:09 +0100

One of the crucial issues in the still open problem of seismic analyses of masonry
constructions is the study of the structural capacity for cyclic loadings; the difficulties are
even more pronounced when constructions embedding curved elements like arches, vaults and
domes have to be studied. In order to develop effective nonlinear numerical models, the latter
have to be capable of representing the relevant aspects of the experimental behavior, and the
mechanical parameters of the model have to be carefully calibrated with reference to suitable
experimental test results. In this paper the outcomes of experimental tests on a tuff masonry
arch under cyclic loading are proposed and discussed, along with the results of experimental
tests on the masonry materials (blocks and mortar) aimed at determining the compressive,
flexural and shear behavior.

Experimental Campaign on the Use of the Flat Jack Test in Cob Walls

Scipedia content — Tue, 30 Nov 2021 14:24:01 +0100

The flat jack test is one of the most used investigation techniques in the area
of architectural heritage conservation. Unfortunately, there are no results available in the
literature reporting the use of the flat jack technique in cob walls. This paper presents the firs
experimental campaign performed to validate the use of this Minor Destructive
Technique (MDT) to determine the levels of stress in cob walls and their mechanical
properties. Furthermore, three workshops organized and facilitated with the aim of
increasing public engagement and awareness towards the conservation of earthen
vernacular architecture are also presented.

Experimental Assessment of Cyclic Shear Response of Brick Masonry Walls Retrofitted with TRM

Scipedia content — Tue, 30 Nov 2021 14:23:52 +0100

As one of the main historical construction materials, masonry is abundant among
the architectural heritage of earthquake-prone areas of the Mediterranean countries.
Earthquake mitigation approaches are now focusing on strengthening solutions based on
compatible and environmentally friendly repair materials. These solutions should efficiently
improve the in-plane lateral strength and displacement capacity, which are the two most
significant parameters considered in the seismic assessment of masonry buildings. This paper
reports an experimental programme on masonry walls composed of handmade solid clay brick
and hydraulic lime mortar, a recurrent typology for historical buildings. Tests under cyclic in-
plane forces were carried out on unreinforced and retrofitted walls. The unreinforced walls
were repaired and retrofitted after being damaged in the first test and were then tested again
to investigate the recovery of strength. The repair consisted in filling the open cracks and
replacing the damaged bricks by following the so-called “scuci-cuci” technique. The
retrofitting consisted of externally bonded textile reinforced mortar (TRM). The investigated
TRM system was a continuous bidirectional grid of basalt embedded in hydraulic lime mortar.
The experimental results show the suitability of the proposed solutions for seismic retrofit and
post-earthquake repair of existing masonry buildings. The research results highlight the
effectiveness of the investigated systems in increasing the resistance and ductility of
unreinforced brick masonry. In addition, the results allow a better understanding of the
behaviour of masonry walls subjected to cyclic horizontal displacement.

Experimental and Numerical Analysis of a FRCM Reinforced Parabolic Tuff Barrel Vault

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

An experimental and numerical analysis of the structural behaviour of a barrel
tuff masonry vault strengthened by a Fiber Reinforced Cementitious Matrix (FRCM)
reinforcement system it is proposed. The geometry and the materials of the vault are
representative of some historical constructions in Apulia (Italy). The vault, under the action
of the self-weight and of a distributed load representative of the infill, has been first damaged
by differential settlement of abutments, and then repaired and strengthened by FRCM
composites. Finally the structure has been subjected to a increasing concentrated load on the
extrados. A 3D heterogeneous FE Abaqus numerical model describing the above mentioned
experimental conditions is carried out in order to reproduce the response of the FRCM
reinforced vault. The obtained experimental and numerical results allows for discussing the
structural behaviour of the reinforced vault, and then the effectiveness of the employed
reinforcement.

Experimental and Numerical Analyses on Sandstone Elements Obtained by 3D Printing

Scipedia content — Tue, 30 Nov 2021 14:23:34 +0100

The international cultural and historical heritage is often subject to degradation
and damage. The main causes contributing to these phenomena are the chemical and
mechanical actions due to acid rain, environmental pollution, and earthquakes. Other causes
are the cycles of freezing and thawing that induce the manifestation of internal stresses leading
to the deterioration of the material and the collapse of structural parts.
In the field of architectural restoration, this problem has been addressed by two main
solutions. The first involves cleaning processes that leave the missing parts visible; the second
consists of introducing reproductions of the missing parts, creating a clear distinction between
pre-existing and new elements. In both cases, the seismic behavior of the structure is modified;
in the second solution, the added elements do not contribute to the structural strength since
they are made of plaster or stucco.
This work aims at presenting a preliminary study on the creation of replacements of missing
elements within damaged heritage buildings. The work is structured in two distinct phases. In
the first phase, specific cubic specimens, created with a 3D printer, are produced and subjected
to uniaxial compression tests. The experimental campaign is carried out in order to provide
useful information regarding the 3D material engineering constants that are currently absent
in the literature. In the second phase, the experimental results are used in a numerical model
to calibrate the mechanical properties of an equivalent homogeneous material.

Excess Capacity in Historic American Reinforced Concrete Floors

Scipedia content — Tue, 30 Nov 2021 14:23:26 +0100

The introduction of reinforced concrete as a structural material in American
practice circa 1900 created unique challenges in design and analysis. Engineers and builders
had to simultaneously determine proper constituent materials for the concrete, the relation
between materials proportions and strength, and formulas for sharing load between steel and
concrete. Early on there were only local building codes, which often treated concrete as
masonry. This was followed, starting in 1909, by the reports of the “Joint Committee” which
served as a de facto national code for concrete; the American Concrete Institute code was
first independently published in 1941 and has been updated regularly since.
All of the early codes, specifically including the Joint Committee report and the ACI code,
used allowable-stress design with a linear-elastic model of flexure. Load-and-resistance
factor design using an ultimate-strength model was first introduced in the US as an alternate
method in the 1956 ACI code, was elevated to equal status with the 1963 code, and was made
the standard in the 1971 code with the linear-elastic allowable-stress model as an alternate.
Since the ultimate-strength model is generally accepted to more accurately represent flexure
in reinforced concrete, the allowable-stress alternate was little used after the transition.
Many details have changed minimally since the 1910s, including provisions for T beams
that take advantage of the slab for additional compression flange area. The calculation of
shear capacity in both concrete and web reinforcing changed minimally except for the
transition from allowable-stress to load-and-resistance-factor design.
Re-analysis of extant concrete structures designed before the 1956 code generally shows a
pattern of significant excess capacity in flexure and limited excess capacity in shear. For
members that are generally not controlled by one-way (beam) shear (two-way slabs and one-
way slabs) the increase in flexure capacity governs; for members where one-way shear is a
controlling factor, the small increase, no change, or decrease in shear capacity governs.
Much of the current literature on evaluating the capacity of extant concrete structures
focusses on strength degradation from material changes such as rusting rebar and from
overall material changes such as carbonation. The presence of excess capacity should also be
considered, and it is possible based on review of the governing codes and design methods to
determine general patterns as to how much excess capacity may be expected.

Evolution of Lateral Design in the United States

Scipedia content — Tue, 30 Nov 2021 14:23:18 +0100

This paper explores the design profession’s evolving understanding of lateral
design. It shows how the United States building codes’ handling of seismic and wind forces
has changed over time, often in response to extreme events or technological developments.
Prior to the early 1900s most buildings were designed without an explicitly defined lateral
force resisting system. Up to that time period earthquakes and strong wind events produced
little in the way of code requirements to address lateral forces. It was the advent of steel and
high-rise construction in the late 19th Century that triggered a need to consider lateral loads.
During the early 20th Century little consensus existed regarding the lateral forces that
needed to be resisted. Wind loading provisions began appearing in the codes of large cities
in the early 1900s, but it would not be until the 1930s that seismic provisions started to be
codified, and then only in California. Throughout the 20th Century significant lateral events
have continued to expose vulnerabilities that have been subsequently addressed with changes
in construction detailing and code restrictions. In the mid-1900s regional building codes
developed, focusing on the lateral hazards present in their locality. By 2000 these regional
codes were replaced by a national code, and lateral design has now started to shift from
prescriptive requirements towards performance-based design. This paper will help structural
engineers better understand the historic building stock by exploring how lateral design has
evolved in the US over the last hundred years.

Evaluation of the Behaviour of Lime and Cement Based Mortars Exposed at Elevated Temperatures

Scipedia content — Tue, 30 Nov 2021 14:23:09 +0100

Exposure to fire and elevated temperatures is diachronically a significant decay
factor, influencing the stability of structures. Cement and lime-based mortars have a different
behavior when exposed at elevated temperatures, usually testified by the post-fire preservation
state of historic and contemporary constructions. In this paper, the correlation of their
properties is envisaged, in order to identify the key elements of their performance. To this
direction, five compositions of cement and lime based mortars were manufactured and tested,
after their exposure at 200oC, 400oC, 600oC, 800oC and 1000oC. The binders used concerned
CEM I42.5Ν (C), hydrated lime (L) and natural pozzolan (P), while the systems applied
regarded C, C:L (1:1), L, L:P (1:1) and L:P:C (1:0.8:0.2) (parts per weight). The aggregates
used were natural of siliceous origin and their gradation varied from 0-4mm to 0-8mm. The
B/A ratio was 1/2 by weight and the W/B ratio was adjusted in order to maintain workability
around 15±1cm. The physico-mechanical properties of the specimens, were recorded before
and after their exposure at the selected temperatures. From the evaluation of the results, it was
concluded that the mortars’ behavior was different at the early temperature rate (up to 600oC)
according to their type, whereas the results were more comparable at the extreme temperature
level. Generally it was observed that although the initial strength of the lime-based mortars
was low (1-4MPa), they presented a more stable and efficient performance at the elevated
temperatures, rendering them probably more resistant at the first stages of fire actions. Cement-
based mortars seemed to present a better performance at the highest temperatures of 800oC
and 1000oC.

Evaluation of Performance of Matured Hydraulic Grouts: Strength Development, Microstructural Characteristics and Durability Issues

Scipedia content — Tue, 30 Nov 2021 14:23:00 +0100

The present paper evaluates the performance of matured hydraulic grouts, with
respect to their composition and the induced microstructural characteristics. Four different
grout compositions were examined; three grouts based on natural hydraulic lime (NHL5),
plain and in combination with pozzolan, and a ternary white cement - pozzolan - hydrated
lime mixture. Both grout-only specimens and composite injected material have been examined
and injected grout - masonry material interaction issues are discussed.

Evaluation of Invasive Retrofitting Interventions on an Unreinforced Masonry Heritage Building

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

The present study case highlights the importance of considering local failures for
irregular unreinforced masonry buildings, by means of nonlinear seismic analyses. Simplified
seismic assessments based on equivalent frame method were used in order to capture the
structural behavior of the National Geological Museum from Bucharest in its initial form and
also the current structural layout.
The retrofitting works realized in the 1982 were focused on strengthening the transversal
masonry walls and on creating horizontal diaphragms to improve the “box behavior” of the
building subjected to lateral forces. Retrofitting of unreinforced masonry walls by reinforced
concrete jacketing and the replacement of flexible floors by reinforced concrete slabs were
previously considered to be effective only though post-earthquake visual inspections of the
strengthened elements. The efficiency of past interventions is studied in the present paper
through comparisons between the two models in terms of damage patterns, global behavior and
also performance levels established function of maximum relative displacements.

Equivalent Frame Method Combining Flexural and Shear Responses of Masonry Buildings

Scipedia content — Tue, 30 Nov 2021 14:22:43 +0100

This work presents the results of quasi-static non-linear analyses of two
masonry buildings using, for the discretization of walls, a macro-element that combines the
bending and the in-plane shear responses. The macro-element uses the force-based beam-
column element equipped with cross sections discretized in fibers, where the behavior of each
fiber is described by uniaxial constitutive models. To describe the shear response of the
structural element, the macro-element embeds a shear hinge at mid-span, with a
phenomenological non-linear constitutive model calibrated on experimental data. The
analyzed buildings are two tangibles examples of un-reinforced and reinforced masonry of
the Italian Heritage. The un-reinforced masonry building is a strategic building monitored
by the O.S.S., partially damaged by the seismic events in Center Italy in 2016. The
reinforced masonry building, a three-storey residential structure, is subject of evaluations
carried out in the ReLuis RINTC project, designed as per D.M. 2018.

Effect of Slow-Moving Landslides on Churches in the Liguria Region: a Geotechnical Approach

Scipedia content — Tue, 30 Nov 2021 14:22:32 +0100

Protecting cultural heritage from water-soil interaction related threats is a current
issue and the prediction of the effects induced on buildings by landslides is very challenging.
The main difficulties lie in the lack of detailed information about landside movements as well
as in the modeling of soil-structure interaction. This paper study the effects of a particular
category of slow-moving landslides, namely active rotational and translational slides with
movement rates of the order of some mm/year, on buildings of historical and cultural interest
such as churches. Three case studies located in the Liguria region (Italy) were analyzed by
performing FEM and LEM numerical analyses on sections representative of the slope.

Effect of Historic Timber Roof Structures on the Structural Behaviour of Masonry Buildings during Seismic Events

Scipedia content — Tue, 30 Nov 2021 14:22:24 +0100

Roofs are complex elements of heritage structures which are not only meant to
protect the building from exterior methodological factors but are also defining the skyline of a
city while highlighting the importance and aesthetics of the building they belong to. However,
in seismic areas, roof structures prove out to either trigger the out-of-plane behaviour of
historic masonry buildings [1] or reduce the horizontal displacement, depending on their type
and their connection to the masonry walls [2]. The study is therefore aiming do highlight the
effect of common roof structure types from Timisoara, a city placed in the western part of
Romania, subjected to shallow earthquakes, on the seismic behaviour of a local type of masonry
structure, with a ground-floor and 2 upper floors, from the 18th century.
Throughout the study, three different types of roof structures were placed on the same masonry
building and the out-of-plane horizontal displacement, inter-story drift, damage level and
internal forces were assessed. The main scope of the study is to highlight how the chosen roof
structures from the 18th, 19th and 20th century, would influence the behaviour of a masonry
building during seismic events. Detailed numerical simulations using finite element models of
the building and the three roof structures were performed in order to obtain the four assessed
parameters, which prove that, depending on the connection to the masonry walls and the state
of conservation of the timber elements, roof structures would significantly improve the seismic
behaviour of historic masonry buildings in this area.

Effect of Geometrical Imperfections on the Response of Dry-Joint Masonry Arches to Support Settlements

Scipedia content — Tue, 30 Nov 2021 14:22:15 +0100

This paper aims to investigate the effects of geometrical imperfections on the
response of a scaled dry-joint arch to the vertical displacement of one support. The arch
behaviour was analysed in the large displacement regime using both physical and numerical
modelling. The experimental tests were performed on 1:10 small-scale models made of bi-
component composite blocks with dry joints. In order to evaluate the geometrical accuracy of
the blocks, two different sets of voussoirs were produced. The numerical simulations were
carried out using a finite element (FE) micro-modelling approach, where the arch was
modelled as an assembly of very stiff voussoirs connected by nonlinear interfaces. Particular
attention was paid to the interface stiffness, which was set so as to tune the numerical model
with the experimental evidence. Experimental and numerical results were then compared in
terms of collapse mechanism, hinge configuration and ultimate displacement capacity. The
imperfections of the physical models were found to significantly affect the arch response.