Scipedia: Documents published in 2021

Early Concrete Structures and Post-Patented Systems: Lessons to Preserve Early 20th Historical Heritage

Scipedia content — Tue, 30 Nov 2021 14:22:04 +0100

Reinforced concrete was introduced by patented systems into Spain towards the end of the 19th c. Early patents were effectively foreign trademarks, although Spanish engineers, architects and industrialists soon developed their own RC systems. Local builders would build structures with scarce little regard for calculated design and construction in the first decade of the 20th century. Nevertheless, as further knowledge was required, increasing research led to new RC standards in numerous countries, such as France and Germany. In the second decade of the 20th century, the use of patent systems declined. The teaching of RC started at the Spanish Civil Faculty where systems of scientific calculation were rapidly adopted, although no Spanish RC standard was drafted, unlike the situation in the leading European countries of that time. Hence, the RC structures that proliferated across Spain were mainly based on French or German standards. Spanish industrial activity began to develop in northern areas of the country where the use of new materials was pioneered over the following decades. Nowadays, some of those structures are listed heritage buildings. In this paper, some common features of 15 RC structures built between 1915 and 1936 are discussed, by focusing on their conservation problems. Preliminary structural reports from engineers, architects, municipal councils and, in some cases, the owners of the buildings are compiled with information on the pathologies affecting the buildings and analyses of structural morphologies, and steel and concrete strengths. The results of those studies are analysed, by connecting construction features with structural conditions, in order to gain a deeper understanding of their main characteristics and similarities. The findings will contribute to knowledge of heritage buildings, identifying key strategies for application in future rehabilitation works.

Dynamic Identification of the So-Called Temple of Minerva Medica: Comparison of Different Instrumentations and Methods for Mutual Validation of the Results

Scipedia content — Tue, 30 Nov 2021 14:21:53 +0100

Dynamic monitoring is a well-established technique used to gain information on
the global health of constructions. In particular, ambient vibration tests have achieved
important results in the dynamic characterization of modal parameters. Several
techniques and instrumentations are currently available, however the accuracy of these
results is often unquestioned. The mutual validation between different modal analysis
techniques is an important procedure to assess the reliability of the results. In the present
paper the ambient vibration tests performed on the so-called ‘Temple of Minerva Medica’
in Rome considering different techniques and instrumentations will be described and
compared. While it is referred to as the Temple of Minerva Medica, the structure is actually a
ruined decagonal nymphaeum in opus latericium that dates to the 4th century AD. Today, the
construction is located between the main central train station (Roma Termini) and the local
tram way. Ambient vibration data were acquired during different campaigns [1] to
characterize the effects of the vibrations and the modal parameters of the structure. This
work deals with the data collected on the 11th of July 2019 within the project “Tecnologie
per il miglioramento della Sicurezza e la ricostruzione dei centri Storici in area sismica”
coordinated by DTC Lazio (Distretto Tecnologico beni e attività culturali). The
instrumentation comprised of several seismographs equipped with triaxial velocimeters
and piezoelectric accelerometers. A variety of techniques were applied to process the
acquired vibration data in order to extract the modal parameters of the studied structure
including PolyMAX, FDD, EFDD, CC-SSI, HVSR and FRF. Comparison of the modal
parameters obtained by each different technique was considered to provide indications on the
reliability of the instruments.

Dynamic Identification of Damage in Brick Masonry Walls

Scipedia content — Tue, 30 Nov 2021 14:21:43 +0100

This paper shows the experimental and numerical analysis developed on a brick
masonry wall of 3x2.5x0.2 m to understand the changes on its dynamic behaviour with different
stiffness situations: (i) original, (ii) loaded with different load levels, (iii) damaged by
horizontal in plane loads, (iv) retrofitted with Textile Reinforced Mortars (TRM) and (v)
retrofitted and damaged by horizontal in plane loads. This analysis has been developed at the
Civil Engineering Lab at the University of Alicante. On this masonry wall a matrix of 8
seismic accelerometers have been installed to evaluate, in plane and out of plane, changes
in the main frequencies, modal damping ratios and modal shapes. By the use of Operational
Modal Analysis techniques the results shows that the changes on the stiffness have
important influence on the main frequencies and in the modal damping ratios. Very low
influence have been detected on the modal shapes due to the low level of external vibrations
generated during the tests. Due to the low level of vibrations inside the lab,the classical application of ambient vibrations for OMA has been not possible and an external white noise force has been introduced on the top the wall by the use of a shaker to generate a general level
of vibrations on the specimen.

Documentation and Structural Appraisal of the Medieval Manor of Potamia, Cyprus: an Interdisciplinary Approach

Scipedia content — Tue, 30 Nov 2021 14:21:33 +0100

This paper aims to present, via a case study, an interdisciplinary approach towards
the comprehensive analysis of historic constructions. The case study monument examined is
the Medieval Manor of Potamia in Cyprus. The work hereby presented was based on a
collaboration between scientists from the fields of archeology, architecture, materials science/
conservation and structural engineering. A thorough review of historical sources was initially
carried out in order to obtain data concerning the history and construction development of the
Manor. Extensive field work was undertaken to study the architectural typology and
construction detailing of the structures and to explicitly map the various agents of pathology.
For the characterization of the historic fabric, masonry materials were sampled and studied at
the laboratory. The accumulated data facilitated the development of a Finite Element
(FE) model, which was used to numerically assess the structure’s seismic response.

Discrete Element Modelling of Single-Nave Churches Damaged after the 2009 Earthquake in l’Aquila, Italy

Scipedia content — Tue, 30 Nov 2021 14:21:24 +0100

The survey of damages after recent earthquakes have shown the fragility of masonry
churches against the out-of-plane overturning of the façade. This failure mechanism is
currently analyzed having recourse to a rigid body model, using either limit analysis with
kinematic approach, or dynamic analysis under rocking motion. However, both the
aforementioned methods neglect the interaction with the lateral walls, leading to an
underestimation of the effective structural capacity under seismic action. The main goal of this
work is therefore to investigate the effect of the interlocking between the façade and the
transversal wall and the influence of the quality of masonry in out-of-plane overturning. For
this purpose, a refined model of masonry through a Discrete Element Method is developed,
based on a detailed recognition of masonry units. The acceleration and displacement capacity
are estimated through quasi-static pushover and pulse-based dynamic analyses and compared
to those calculated for the rigid body model. The proposed methodology is then applied to a
sample of three single-nave masonry churches that suffered damages during the 2009 L’Aquila,
Italy earthquake.

Digitization of Cultural Heritage Buildings for Preventive Conservation Purposes

Scipedia content — Tue, 30 Nov 2021 14:21:15 +0100

This work aims at presenting the experimental results obtained by the application
of one of the digital protocols developed during the European project HeritageCare:
Monitoring and preventive conservation of historical and cultural heritage. These protocols
are devoted to the preventive conservation of heritage constructions and its assets. More
specifically, the application of the second level of services of the HeritageCare system is
presented through two complementary case studies: a large Neo-Manueline church situated
nearby Guimarães, Portugal, and a small Romanesque church located in Palencia, Spain. In
each case study a different set of digital technologies was employed with the aim of evaluating
the flexibility of the developed protocols. This set of technologies comprises the use of in-house apps for enhancing the visual inspection together with geomatic techniques based on static and
wearable laser scanners as well as digital single-lens reflex and as-built 360º cameras. The
results obtained by the application of these digital tools have allowed the creation of a Web-
GIS platform for ensuring the proper documentation of cultural heritage and streamlining the
management of their conservation process according to a proactive approach.

Diagnosis of an Unusual Structural Instability: the Case Study of the Cathedral of San Lorenzo in Viterbo

Scipedia content — Tue, 30 Nov 2021 14:21:07 +0100

The cathedral of San Lorenzo is a Romanesque church sited in Viterbo (Lazio, Italy),
founded in the XII century on a site characterized by a complex archaeological stratification.
The building is a fine example of religious monumental architecture, built upon well-laid
masonry walls, made of squared blocks of piperine stone and very thin layers of mortar.
Its basilica-shaped plant is divided into three aisles by two rows of marble columns connected
by arches. The structure, that has undergone many transformations during the centuries, was
severely damaged during the II world war and a restoration executed in 1947 has brought it
back to its romanesque appearance.
Currently, a peculiar crack pattern can be observed in the structures, which is mainly
characterized by recurring sub-vertical fissures appearing on the keystones of the arches that
run along the central nave.
The purpose of this paper is to illustrate the diagnostic path which enabled to rule out the most
common damage mechanisms, as a main cause of the damages, and led to the identification of
the most probable cause for the instabilities.
A critical reading of the geometry of the cracks, supported by several static verifications,
resulted in the exclusion of mechanisms associated with the arches thrust actions or with the
compressive stresses in the walls. The hypothesis of soil settlement is rejected by the mechanical
characteristics of the foundation soil, provided from a previous study.
An original diagnostic hypothesis of tensile stresses induced by thermal variations is
formulated and a fully coupled temperature-displacement analysis is carried out, with the FE
software Abaqus, to investigate the effects of the thermal gradient on structures behavior.

Development of a Wireless Acceleration Measurement System

Scipedia content — Tue, 30 Nov 2021 14:20:58 +0100

The newly developed low-cost micro-electro-mechanical system (MEMS)-based
acceleration sensors exhibit sufficient accuracy and stability to monitor the shaking of
structures caused by an earthquake. We have developed a practical shaking-monitoring
system using MEMS-based acceleration sensors and a 920 MHz multi-hop radio
communication method that offers reliable radio wave communication, even within buildings.
In this system, the base clock of each sensor unit must be closely synchronized to the master
clock to minimize acceleration-induced phase synchronization error. In the proposed system,
this error can be limited to three milliseconds in a system of multiple sensor units.

Development of a Neural Network Embedding for Quantifying Crack Pattern Similarity in Masonry Structures

Scipedia content — Tue, 30 Nov 2021 14:20:49 +0100

The degree of similarity between damage patterns often correlates with the likelihood
of having similar damage causes. Therefore, deciding whether crack patterns are similar is one of
the key steps in assessing the conditions of masonry structures. To our knowledge, no literature has
been published regarding masonry crack pattern similarity measures that would correlate well
with assessment by structural engineers. Hence, currently, similarity assessments are solely
performed by experts and require considerable time and effort. Moreover, it is expensive, limited by
the availability of experts, and yields only qualitative answers. In this work, we propose an
automated approach that has the potential to overcome the above shortcomings and perform
comparably with experts. At its core is a deep neural network embedding that can be used to calculate a numerical distance between crack patterns on comparable façades. The embedding is
obtained from fitting a deep neural network to perform a classification task; i.e., to predict the crack
pattern archetype label from a crack pattern image. The network is fitted to synthetic crack patterns
simulated using a statistics-based approach proposed in this work. The simulation process can account for important crack pattern characteristics such as crack location, orientation, and length. The embedding transforms a crack pattern (raster image) into a 64-dimensional real-valued vector space where the closeness between two vectors is calculated as the cosine of their angle. The proposed approach is tested on 2D façades with and without openings, and with synthetic crack patterns that consist of a single crack and multiple cracks.

Development of a Fire Damage Index for Immovable Cultural Heritage

Scipedia content — Tue, 30 Nov 2021 14:20:41 +0100

Available fire risk assessment approaches are mostly developed for new buildings.
These approaches encompass minimum provisions defined by standards that are valid in
certain countries, and few of these methods were thought exclusively for assessing the fire safety
of cultural heritage. Given the diversity and specificity of cultural heritage assets, simple
approaches are thus required to analyse their fire safety and establish their risk mitigation
needs. In this context, a simplified fire damage index dedicated to assessing the fire
vulnerability of immovable cultural heritage assets is proposed. The proposed index is the result
of a weighted multi-parameter evaluation that can be correlated with the level of damage that
the cultural heritage asset (including its contents) is expected to suffer under a fire. The
proposed index involves twenty-one indicators divided into four categories and offers a flexible
approach for universal applicability. The performance of the proposed approach is illustrated
for two case studies in Portugal. The results highlight the advantages of having a simple
methodology that can be used for the preliminary risk analysis of a large number of assets to
identify those requiring risk mitigation measures or detailed and resource-demanding analyses.

Determining Qualities of Photogrammetric Models for the Use of Monitoring Movements in Stone Candis in Central Java

Scipedia content — Tue, 30 Nov 2021 14:20:33 +0100

The Candis (temples) of Java represent sophisticated ancient building heritage
and are key features for Javanese people to identify with their own culture. Candis occupy a
significant position in the cultural history of Southeast Asia and rank among the most
outstanding examples of Buddhist and Hindu architecture. Well-known Candis such as
Borobudur or Prambanan are also top-ranked tourist destinations.
This ancient heritage is threatened by Indonesia’s geographical location within the Pacific
Ring of Fire, a tectonic subduction zone prone to environmental catastrophes such as
earthquakes, volcanic eruptions and the resulting tsunamis. Previous work presented a
monitoring workflow for analysing variations in the geometry of these temples to gain an
understanding of structural changes produced by seismic events. As part of that workflow, we
proposed a combined laser scanning and UAV-supported image match point cloud model which
can be compared to a photogrammetric data set in order to provide a quick, inexpensive, and
easily accessible monitoring technique. While methodology has already proved useful, some
aspects still need to be refined. Also, further understanding about the structural composition of
the objects being examined and what changes of geometry can be expected within the analysis
after earthquakes needs to be collected.
An analysis is presented of changes that have happened within the structure over a period
of several years and numerous seismic events to facilitate an understanding of geometric
changes that can occur. Furthermore, this re-evaluation by laser scanning will be compared to
a set of image-match models to investigate factors that have an impact on the reliability and
accuracy of such models. Manuals drafted by the project team and introduced in previous work
explain how to capture image data to be processed into photogrammetric models. Amendments
and revisions will be made to these manuals based on new data and experiences collected
during the ongoing Candi Sari case study presented in this paper.

Design of Shake Table Tests of Multi-Leaf Masonry Walls Before and After Retrofitting

Scipedia content — Tue, 30 Nov 2021 14:20:22 +0100

A significant proportion of the built heritage in historic centres is constituted by
rubble stone masonry structures. Collapses by leaf separation and disaggregation observed
after earthquakes highlight their dramatic vulnerability, especially under out-of-plane loads.
Nevertheless, their dynamic response still needs to be fully investigated and their capacity may
be overestimated by assessment approaches based on rigid-body mechanics. Effective
retrofitting solutions are also needed to protect human lives and safeguard the built heritage,
while ensuring the conservation of its architectural value. This paper describes the design of a
shake table investigation on stone masonry walls, whose materials and arrangement reproduce
those surveyed in the villages of central Italy struck by the 2016-2017 earthquake sequence.
The test setup was conceived to induce out-of-plane vertical bending under earthquake base
motion and investigate the dynamic response of multi-leaf rubble stone masonry and the gain
in seismic capacity that can be achieved with mortar-based composite reinforcements, designed
to prevent the leaf separation and disaggregation of the wall without compromising its fair
face.

Design of Protective Structures for Active Archeological Sites

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

This paper presents a structural design methodology in order to find the best
possible solution of protective structures for active archeological sites. Besides the typical
demands for construction on these sites which arise from the typology and the level of
protection of cultural heritage, active archeological sites require a structural solution with
regard to time and direction of further excavation. The hypothesis is that modular
spatial structures which are easily assembled or disassembled, and have the ability to be
extended in one or more directions, are the most functional solution for these sites.
This paper shows the analysis of several types of spatial structures based on the
requirements of active archeological sites. It explores the possibilities of structural systems
derived from multiplication of one primary element of structure, their material and joints
between elements. The most adequate assembly of the entire structure is supposed to
be found in the interdependency of the load and the dimension of the element’s cross-
section, in a suitable geometric configuration. The focus of the analysis is on structures
made of short-bearing elements which have the advantage of the efficiency of transport and
assembling.
One of the design criteria for this methodology is that the structural system itself looks
simple and elegant in order to complement the archeological site. This is shown in the paper
through the analysis of patterns in which these structures are assembled. The aim is to
correlate the position of the elements in the structural system, the dimensions of cross-section,
and the lengths of the straight beams which form the spatial structure in order to find a
simple, functional and economical solution for protective structures at active archeological
sites.
The conclusion shows the advantages and disadvantages of the design methodology
presented in the paper, as well as the discussion about the analyzed spatial structures. This
type of methodology that systematizes various design criteria from different fields of
research engages the problem of design of protective structures for archeological sites and opens up new questions for further research.

Design Criteria and Procedures for Archaeological Shelters: Towards Flexibility Thanks to Algorithmic Modelling

Scipedia content — Tue, 30 Nov 2021 14:20:05 +0100

Many examples of archaeological shelters can be found over sites and a wide
range of literature illustrates their features. However, it seems that only a few have passed
through a proper assessment phase of their effectiveness and compatibility to the
archaeological remains. which is mainly due to proper detailing of the building solution in
respect of general conservation criteria. Furthermore, in some cases, shelters have proven to
worsen environmental conditions that they are supposed to protect. In this paper design criteria
for archaeological shelters are proposed, in respect of the three main themes recognized as
crucial: general architectural quality, conservation effectiveness, structural and functional
detailing. To deal with the wide range of cases where such criteria must be applied, an
innovative tool providing the desired flexibility in the design procedure is taken into
consideration. Algorithmic modelling in Grasshopper environment, a plugin for Rhinoceros 3D
software, offers the required features thanks to a linear workflow, where the general
characteristics of the structure as far as its structural details can be implemented. Every
element is represented by a set of parameters in the plugin rather than a single object in the
‘parent’ modelling tool, thus allowing easy change to the design. Other plugins provide
additional tools for specific tasks, such as finite element analysis, safety verifications and
structural optimization. The paper presents the methodology for the implementation of the
entire workflow and the preliminary assessment of its results, from the structural and
architectural point of view, showing good adaptability to several possible design choices
(position of pillars, truss number, roof pitch, etc.). Structural optimization is also executed. The
future implementation of environmental parameters (e.g. daylight, ventilation, temperature), as
an additional set of restraints, will complete the framework on which a final assessment will
take place.

Decision Support System for Vulnerability Assessment of Masonry Churches Including Architectural and Artistic Assets

Scipedia content — Tue, 30 Nov 2021 14:19:57 +0100

The heritage building stock represents a significant element at risk from earthquakes, as recent
seismic events have shown, especially in the Mediterranean area. In fact, in the last few years,
the issue of assessing its seismic vulnerability has been widely discussed by the scientific
community. The vulnerability assessment procedures involve many critical points related to the
complexity and uncertainty of the parameters involved. If a detailed analysis of the individual
buildings is to be performed this of course requires a great effort in both the data retrieval,
modelling and analysis phases.
In particular, historical masonry churches have been studied in detail in Italy and empirical
approaches have been proposed in which a vulnerability index based on the classification of
recurrent failure mechanisms is defined, exploiting a macro-elements approach to identify the
parameters that influence the index. On the other hand, intangible aspects related to the
architectural, historical and artistic value are not included in the Index, either in the structural
parts themselves or in additional non-structural elements or contents.
This paper proposes a procedure that combines the well-known vulnerability analysis based on
the macro-elements approach and classification of recurrent failure mechanisms with an
evaluation of the church’s architectural and artistic assets, such as frescoes, statues and
paintings, by applying the Analytic Hierarchy Process. The novel procedure is integrated in a
useful Decision Support System to provide a complete overview of a church’s structural
condition, including its artworks, in order to create a priority scale for the assessment,
retrofitting and protection of existing masonry churches.

Decay Patterns and Damage Processes of Historic Concrete: A Survey in the Netherlands

Scipedia content — Tue, 30 Nov 2021 14:19:48 +0100

Historic concrete buildings (end of 19th century – 1960s), because of their
“experimental” character, require a specific approach to both survey and conservation.
Although they were built with empirical approaches, some buildings show a fair state of
conservation and resilience –even though they have already exceeded the 100-year
threshold– while others of comparable age are in severe need of restoration.
As part of the European project CONSECH20, aimed at contributing to the conservation
of cultural-heritage concrete buildings, this paper investigates what are the most common
types of damage and hypothetical causes, and what direct and non-direct parameters can lead
to a faster or slower deterioration of historic concrete in the Netherlands. The research is
based on an initial screening study, which will be used as a basis for a larger research among
the participant countries.
The current research is divided in three phases. Firstly, a selection of 15 case studies
from the Netherlands are investigated; the selection was based on criteria of age, state of
conservation and type of ownership. Secondly, the history and materials of the buildings
are examined. Thirdly, an on-site visual survey is performed per each building, with pre-
design templates, to identify types of damage, extent and severity. The data is then analysed
combining different factors with a calculated index of severity. Results are discussed and
contrasted to provide further clarification of the degradation of historic concrete. A fourth
phase, not discussed in this paper, will use this methodology in a broader context, with a
larger number of case studies in different countries.
The results indicate that the majority of types of damage are related to corrosion, being
the hypothetical cause carbonation-induced corrosion. The outcomes of the investigation
point out that the factors with a higher impact on the durability are the environment,
the use and maintenance of the buildings, the existence of a sacrificial plaster in exposed
elements, and the type of ownership.
Considering the limited number of buildings, the conclusions presented in this paper will
be further contrasted with a larger number of case studies.

Data Analysis Using ARX Models Applied to Static Structural Health Monitoring of the Monastery of Sant Cugat

Scipedia content — Tue, 30 Nov 2021 14:19:40 +0100

The church of the monastery of Sant Cugat close to Barcelona is a medieval
construction characterized by a complex structural behaviour stemming from the interaction
among various structural elements built over different periods. Despite having survived for
several centuries, such structures are often affected by slow irreversible deterioration
mechanisms that can jeopardise their stability in the future. In order to identify such
mechanisms at an early stage, and to better understand the cause of visible pathologies, a static
structural health monitoring (SHM) system was installed in the church since 2017. Although
this monitoring strategy, aimed at the continuous measurement of key slow-varying parameters,
has been used successfully in the past to facilitate the diagnosis of this structural typology, the
interpretation of data collected by such systems remains a challenging task. One of the main
reasons for this is the fact that many monitored damage and deformation features are sensitive
to changes caused by environmental conditions. To address this issue, this paper presents the
application of a fully automated data analysis procedure to the records collected from the SHM
system installed in the church of the monastery of Sant Cugat. The procedure consists of two
parts. The first relies on the identification of models that comprehend an Auto-Regressive
output and an eXogenous input (ARX) to represent the dynamics of each monitored response
using suitable environmental parameters as predictors. The identified models are then used to
estimate filtered evolution rates. The second part of the procedure involves classifying each
monitored response into pre-defined evolution states based on outcomes from the first part. The
main results from the application to the case of the church of the monastery of Sant Cugat are
presented and the implications for the diagnosis of the structure are discussed.

Data Acquisition, Management and Evaluation for Stone Conservation Projects with Digital Mapping

Scipedia content — Tue, 30 Nov 2021 14:19:31 +0100

Several years of experience in heritage documentation have given a background
to develop methods of digital photogrammetry and mapping. The outcome is the development
of a mapping software over a period of 20 years.Main features of the software are
image rectification, vector based mapping, quantity survey and data analysis. In
Germany, it is mainly used in the field of stone conservation. Small projects can be
processed as a single mapping project, whilst complex projects like a cathedral can be
organised as a hierarchical project, with several mapping projects for individual object
parts. Each mapped element can be connected with additional attributes. This allows
visual analysis of mapping activities, quantities and attributes – like in a geographical
information system (GIS) for conservators. Tools and procedures for efficient mapping
are developed in close cooperation with conservators from different fields. It is shown
how large stone objects can be managed efficiently with an example project from the field
of natural stone. This applies to the overall data acquisition and data evaluation for
condition analysis, conservation planning, accounting documentation and monitoring.
Due to the advances in the fields 3D laser scanning and digital photogrammetry
within the past 5 years the R&D project „PROQUATO“ (2016 – 2018) was
initiated by fokus GmbH Leipzig with the institute for photogrammetry and remote
sensing of TU Dresden and Scan 3D GmbH, Berlin. Project results for efficient data
processing and functions for 3D mapping will be presented. Current developments deal with
the fast processing of point clouds scanned by laser scanner for the use as reference for
image rectification, deformation analysis and creation of section lines.

Damages Patterns in Historical Temples of Puebla, Morelos and Oaxaca after September 2017 Mexico Earthquakes

Scipedia content — Tue, 30 Nov 2021 14:19:21 +0100

A brief description of the damages observed after the occurrence of the September
2017 earthquakes in some temples located in the states of Oaxaca, Puebla and Morelos is
presented. A total of 48 temples were visited where we observed partial or total collapses of
structural elements as: towers, roofs, buttresses, walls and arches in the temples. In some
cases, the level of the damage was so severe that compromised the stability of the temples.

Dacian Fortresses in Orastie Mountains: Management of Heritage Structures

Scipedia content — Tue, 30 Nov 2021 14:19:12 +0100

The protection of the built and archaeological heritage is an increasingly debated
topic in recent years. In order to protect these valuable historic structures and preserve them
for the future, holistic approaches are necessary. These generally involves a wide range of
specialists and collaborators, multidisciplinary way of developing conservation strategies,
while maintaining their original features.
However, recent studies highlight the fact that the management of heritage sites and buildings
is far more than the simple aesthetic and structural repair. It means acknowledging the role of
societies and communities in maintaining the importance of these structures and the risk of
environmental factors (climate change challenges or earthquake risk) on their state of
conservation and the effect of unauthorized interventions over time.
Therefore, based on the case study of Orastioara, a commune in Hunedoara County, Romania,
where 3 UNESCO heritage sites (from a total of 6 UNESCO sites in the area) can be found and
numerous monuments of national and local importance, the study is presenting the challenges
encountered during the development of the general urban plan of the commune, in relation with
all the establishments that conserve Dacian fortresses – sites UNESCO; and also a proposal
for the future management plan of the protected sites. Since the heritage structures have been
neglected over the years, the paper comprises a general overview of the complexity of the
developed conservation strategy, in order to be able to manage the heritage structures while
taking the particularities of their context into consideration.

Cyclic Tests on Thin Masonry Vaults Strengthened Through Composite Reinforced Mortar

Scipedia content — Tue, 30 Nov 2021 14:19:04 +0100

The paper deals with the strengthening of thin masonry vaults by means of a CRM
(Composite Reinforced Mortar) strengthening technique based on Glass Fiber-Reinforced
Polymer (GFRP) meshes embedded in a 30 mm thick mortar matrix, applied at the vault
extrados or intrados and connected to the masonry abutments through steel bars and GFRP
elements. The experimental campaign concerned quasi static cyclic tests performed on four
full-scale samples, supporting their self-weight only and subjected to uniform horizontal
transversal loading. The results of the tests are described in terms of crack pattern, failure
mode and load-displacement graphs, referring both to the horizontal displacement monitored
at the crown section and to the sliding at the spring sections. High improvements in terms of
both resistance and displacement capacities emerged in respect to the plain masonry and the
connection with the abutments resulted fundamental for ensuring the reinforcement
effectiveness.

Cultural Heritage Exposed to Natural Hazards: the Case Study of the Convent of San Domenico in Maiori

Scipedia content — Tue, 30 Nov 2021 14:18:54 +0100

Nowadays it is widely recognized that structural interventions on cultural heritage
buildings shall comply with the minimum intervention principle. The main goal is to enhance
the structural capacity respecting, at the same time, the authenticity of the monument. As such,
the correct interpretation of the current damage is a first fundamental step in the design of an
efficient structural intervention. Within this framework, the paper presents the results of an in
depth investigation carried out to assess the structural capacity of a complex monument
affected by several deficiencies. The case study is the convent of Saint Domenico, a seventeenth
century’s masonry structure, belonging to the traditional architectural typology of the court
building. The building is located in Maiori, a small town in the Amalfi Coast (Italy), included
in the UNESCO World Heritage List since 1997 for its great cultural and naturalistic interest.
The structure was abandoned during the 80s, and currently presents an extensive and diffuse
crack pattern that is the consequence of several causes such as: the natural aging of material,
the lack of maintenance, the modifications occurred during the centuries, the seismic events
occurred in the past and the poor quality of the foundation soil. In this paper, starting from the
knowledge acquisition path of the whole Convent, a special focus on the structural behavior of
the East wing is provided. A numerical model of a cross section of the wing has been developed
and analyzed considering the effects of lateral loads and settlements. The numerical analyses
are carried out using LiaBlock_3D, an in-house software tool for the limit equilibrium analysis
of rigid block assemblages. Results of the analyses are discussed in details and a comparison
with the actual crack pattern of the structure is provided as well.

Criteria for the Vulnerability Analysis of Structural Aggregates in Historical Centers

Scipedia content — Tue, 30 Nov 2021 14:18:45 +0100

The need to define earthquake prevention and intervention strategies, in order to
limit dramatic consequences for the society, has acquired a high priority in countries where,
like in Italy, a large number of historic masonry buildings (listed or not) are located in areas
with medium to high seismic hazard. From the point of view of the level of safety to be
reached through interventions, the concept of improvement, as opposed to that of full
strengthening, is nowadays widely accepted in the case of monumental heritage; what is still
lacking, in many cases, is a procedure for the vulnerability analysis, as a synthetic evaluation
tool for the definition of intervention priorities. In a modern perspective, where territorial
planning is conceived as a safety project for the territory, the seismic vulnerability analysis
should not be confined to specific technical documents, but should rather be considered at a
general level; in this way only, indeed, the issue of seismic risk could acquire widespread
knowledge and awareness in the population, also pushing urban planning in the direction of
general programs for the increase of seismic safety. In the above perspective, revised criteria
have to be developed for a global vulnerability assessment, to be introduced at a general level
in territorial planning. Considering that seismic vulnerability analyses are strictly dependent
on specific building typologies, attention has been focused, in the present study, on to the case
of structural aggregates in historical centers, thus following the needs of the Italian Civil
Protection Agency in relation to seismic prevention activities in historical towns. The
research, which is still in progress, takes advantage from the application to a few study cases,
suitable for the experimental testing of procedures.

Cost-Effective Implementation of Nitinol to Improve the Seismic Performance of an Unreinforced Masonry Building

Scipedia content — Tue, 30 Nov 2021 14:18:38 +0100

Congregation Sherith Israel, one of San Francisco’s lesser known gems, is an
historic unreinforced masonry building with a naturally lighted dome that rises over 100 feet
above its centerpiece --- an ornate mural painted vaulted sanctuary that occupies nearly 90
percent of the plan area of the building. Though damaged only modestly by the 1906
earthquake that destroyed many of its unreinforced masonry neighbors, it was subject to a
local seismic upgrade ordinance. Various innovative strengthening techniques --- including
the first known use in North America of super-elastic nitinol for seismic resistance ---
were implemented to supplement the structure’s inherent strengths. The design was
developed to permit historically significant features to remain virtually undisturbed;
construction was completed in 2017.
The building was required by the municipality to be strengthened to meet seismic
safety standards for assembly occupancy. Following years of study, a strengthening plan
that was feasible and cost-effective, yet would not harm the historic interiors and exterior, was
developed and installed. Construction involved an initial phase of more traditional
strengthening in 2010 to maintain occupancy on an interim basis, followed by a second
phase of innovative technologies to achieve full compliance.
The strengthening philosophy relied heavily on supplementing, rather than supplanting
the existing building’s strengths and leveraging its natural dynamic characteristics. The nitinol
was designed to provide cost-effective easy-to-install structural “fuses” within an
octagonally-configured tension tie system to promote re-centering and control out-of-phase,
out-of-plane behavior of the vulnerable gable end walls, parapet and arches that define the
main facades. Though the nitinol interconnects all four gable end walls, the octagonal
configuration of the system causes no disruption to the domed sanctuary by circumventing
the interior dome, and the sanctuary today is in the same condition as before the project.
The supplemental seismic work included a fiber reinforced polymer catenary and rocking
compression-only pilasters to control displacements without incrementing the demand on its
floor-to-wall ties.

Correlation Studies for the In-Plane Analysis of Masonry Walls Based on Macroscopic FE Models with Damage

Scipedia content — Tue, 30 Nov 2021 14:18:29 +0100

This study explores the use of macro-modelling techniques based on smeared crack
and damage-plastic constitutive laws for the cyclic in-plane analysis of masonry panels. The
numerical investigation is focused on two material macromechanical models, known as Total
Strain Cracking and Crack and Plasticity models. These show some limitations when analysing
the behaviour of masonry structures subjected to in-plane cyclic loading. A modified version of
the Drucker-Prager model including cohesive softening is introduced to overcome these
shortcomings.
A suite of numerical simulations is performed referring to an experimental campaign on two
masonry (squat and slender) panels. A comparison of distinctive features of flexural and shear
response of masonry panels is addressed. The results derived from the two FE macro-models
are compared with the experimental outcomes, highlighting the effects of geometry, stiffness
degradation, and post-peak energy dissipation. Furthermore, a comparison with another
macromechanical model is performed.

Continuous Structural Monitoring of Adobe Buildings: Summary of a Three Years Experience in Peru

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

The paper describes in detail the application of a vibration-based structural health
monitoring system installed in the “San Pedro Apostol” church of Andahuaylillas located in
Cusco (Peru), a 16th century adobe church considered a representative example of South
America baroque architecture. The results of three years of long-term vibration and
temperature and humidity monitoring program are reported in detail in the paper, with a focus
on the long-term and short-term correlations between natural frequencies and environmental
parameters. The results demonstrate that an accurate estimation of the first eight frequencies
in the range 2-6 Hz is possible in the case of complex adobe structure and the existence of an
annual cyclical behavior of the natural frequencies with a clear correspondence with the
changes in environmental conditions due to seasonal influences. The performed correlations of
ambient conditions and structural parameters confirmed the presence of different timescales
and their not negligible influence in the case of a vibration-based structural health monitoring
assessment of adobe systems with large thermal inertia large thermal inertia.

Constructive Analysis and Modelling of a Single Nave Church: a Proposal for S. Sebastiano (EN, Italy)

Scipedia content — Tue, 30 Nov 2021 14:18:09 +0100

The seismic events occurred in Italy in the last decay (L’Aquila 2009, Emilia
2012, Central Italy Earthquakes 2016/2017) have caused the collapse of numerous historical
buildings and monuments with loss of life and irreversible damages to the cultural heritage.
An effective seismic prevention would avoid, or delay, the most frequent collapse
mechanisms. However, it requires a correct interpretation of the structural mechanical
behavior. With regard to the traditional masonry buildings, this issue presents a high level of
complexity due to the uncertainties related to the materials and the constructive techniques.
Furthermore, historic buildings are often the result of several modifications that induce
significant structural irregularities. A possible analysis strategy is provided by a discrete
macro-element modelling (DMEM) approach which is able to simulate the global behavior of
traditional fabrics, if supported by an adequate level of historic, geometrical, constructive
and structural knowledge. In this paper a multidisciplinary procedure is applied to the church
of S. Sebastiano in Regalbuto (Italy), considered as case study. This procedure is composed of
three steps: the knowledge phase in which the constructive apparatus and the static schemes
are identified, the modelling phase and the assessment phase in which the current safety level
of the building and possible interventions that would be compatible with its cultural instance,
are individuated. According to the followed procedure, different scenarios of intervention,
characterized by increasing levels of benefit and invasiveness, are considered. For each
scenario, non-linear static push-over analyses are performed, to evaluate the benefits and
identify the structural critical issues, useful to individuate the next scenario. The obtained
results are presented and discussed both in terms of capacity curves and failure mechanisms.

Conservation of Historical Reinforced Concrete Structures

Scipedia content — Tue, 30 Nov 2021 14:18:01 +0100

During the 20th century, reinforced concrete brought historical structural systems
back into modern times, transforming them into high-performance structures. Reflection on
early reinforced concrete structures of two ancient structural systems, the dome and the girder,
is presented through two Transylvanian monuments: the reinforced concrete cupola of the
Hungarian Theater of Cluj, the earliest structure of this type, and the one-way hollow block
slabs of Villa Tataru designed as a duet, by Gio Ponti and Elsie Lazar. Diagnosis and therapy
of the hundred-year old, “new” historical structures are described. Uncovering these
remarkable, but nearly unknown buildings, the paper intends to contribute to the understanding
of cultural heritage and to raise public awareness towards the fundamental principle of
UNESCO: “The cultural heritage of each is the cultural heritage of all”.

Conservation of Architectural Complex of Manguinhos, in Rio de Janeiro, Brazil

Scipedia content — Tue, 30 Nov 2021 14:17:52 +0100

The aim of this paper is to report on the history and conservation interventions of the
historic architectural complex of Manguinhos, in Rio de Janeiro, one of the most significant and
symbolic architectural ensembles in Brazil. It is the headquarters of the Oswaldo Cruz
Foundation – Fiocruz, under the supervision of the Brazilian Ministry of Health, the most
prominent institution of science and technology on health in Latin America. It was protected by
the National Historic and Artistic Heritage Institute (IPHAN) in 1980. The construction of the
complex started in 1904 on the initiative of the renowned Brazilian scientist Oswaldo Cruz and
was designed by the Portuguese architect Luiz Moraes Júnior. The main monument of the
architectural complex, the Moorish Pavilion, received varied influences of styles and the décor is
a reference to Alhambra. An architectural reading of the complex of Manguinhos will be made,
examining the architectural language adopted on the historical buildings in particular the
Moorish Pavilion; the material and building systems used in its construction; its meaning for the
city and the heritage designation process, the surrounding environment in various periods, and
the physical, functional and visual relationship with the city. Regarding the restoration works
method, the following will be examined: causes of deterioration; diagnosis and state of
conservation; interventions performed over the years; and the project and methodology and the
latest intervention works. The conclusion, will analyze the interventions undertaken in the light
of modern principles of cultural heritage preservation, the importance of the restoration works
of the complex of Manguinhos, and its use as a public cultural and scientific space for the city.

Conservation of 20th Century Concrete Heritage Structures in Cyprus: Research and Practice

Scipedia content — Tue, 30 Nov 2021 14:17:44 +0100

The conservation of 20th century concrete heritage structures poses a major
challenge worldwide. Whilst these structures possess a remarkable architectural value
and a rather experimental character in terms of the use of materials and technologies, at the
same time there is admittedly lack of recognition of their cultural and historical value by the
wide public. More often than not, such buildings are left to deteriorate and often they are even
demolished. This paper follows the workings of the project “CONSErvation of 20th century
concrete Cultural Heritage in urban changing environments” (CONSECH20). The
aforementioned international interdisciplinary project aims to investigate concrete
constructions built until 1965 in four different European countries (Cyprus, Italy, The
Netherlands and the Czech Republic), in terms of their architectural, social and historical
value, and to address their restoration and re-use potential. The paper initially presents
the significance of 20th century concrete heritage structures in general, and describes the
methodology proposed in order to ensure the protection of such buildings from demolition,
and facilitate their restoration and re-use (if and where possible) for the benefit of the
society. The focus is on the structural assessment and restoration of 20th century concrete
heritage buildings in Cyprus, following the methodologies described by modern codes for the
assessment and retrofit of existing concrete structures. A new practical analysis approach is
described and compared to the force-control approach of the pushover analysis of Eurocode
8:3, which significantly overestimates the demands for seismic upgrading. The two
aforementioned approaches are examined for a specific case study concrete heritage building
in Nicosia, Cyprus.

Conservation Beyond Consolidation for Prehistoric Monuments: Finding Narratives from Archaeology to Architecture for Scottish Brochs

Scipedia content — Tue, 30 Nov 2021 14:17:36 +0100

The sophisticated drystone Iron-Age brochs of Northern Scotland, called Complex
Atlantic Roundhouses by archaeologists, have shown a relatively high technological culture.
Their architectural conservation should strike a balance in presenting their key
features (structure, materials, building use and architectural elements) in a concept of
wholeness that integrates its major phases rather than design unity of a hypothetical original
form. However, currently there is uncertainty due to the lack of agreement for a standard
broch scheme and the need for more archaeological research. As most brochs in Scotland are
fragile ruins and only a few of them have been scientifically explored, they have been
conserved through basic consolidation for safety reasons in very localized methods,
primarily by archaeologists. All of them are open to the public but only a few are developed
as tourist sites. In both situations, none has shown the complete features of anything close to a
standard typology as a narrative of their origin and a few have interpreted correctly the
changes after Iron Age as narratives for modification. Significant conservation was
conducted often before full archaeological excavations and did not lead to a satisfying
architectural experience, so people still have a inconclusive image of brochs after a visit.
This paper studies the brochs through their collective concept as a building typology rather
than separate images of different sites. Conservation for brochs in Scotland could argue for
modern holistic projects that go beyond consolidation, exporting narratives from
archaeology to architecture.

Compressive Behaviour of Bonded Brickwork Wallettes with Various Thicknesses: Experimental and Numerical Verification

Scipedia content — Tue, 30 Nov 2021 14:17:27 +0100

Bonded brickwork loadbearing walls are commonly seen in many colonial period
structures around the world; however, most research studies in the past and the current
design provisions are primarily based on single leaf brickwork. Due to the anisotropic natu re
of brickwork, the strength and deformation characteristics would be different for bonded
brickwork walls and their design using the provisions of single leaf bonded brickworks may
be un-conservative. Therefore, to understand the compressive behaviour of differently bonded
brickworks, an experimental programme followed by a numerical investigation were carried
out in this research. The experimental programme comprised of testing nine wallettes under
uniaxial compression. Three different types of bonded thicknesses (single, double and triple)
were used to construct the wallettes. The experimental results are presented and discussed in
terms of failure modes, compressive strengths and stress-strain responses obtained. Further a
numerical investigation based on the micro modelling approach was employed to verify the
experimental findings. The experimental and numerical modelling results indicate that the
change in brickwork thicknesses does not significantly increase the compressive strength of
the masonry. The increased number of weak perpend joints in the bonded brickwork wallettes,
could be a reason of lower strength and thus, a general notion of increment in compressive
resistance due to the reduction in slenderness i s not applicable for bonded brickwork.
Parametric analyses were also carried out and reported for different slenderness ratios to
extend the understanding on the behaviour of bonded brickworks under compression.

COMPAS Masonry: A Computational Framework for Practical Assessment of Unreinforced Masonry Structures

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

In recent years, our (academic/theoretical) understanding of the behaviour
of unreinforced masonry (URM) structures has improved significantly, and many
advanced technological solutions for conservation have been developed. However, there is
still a lack of appropriate methods and tools that can be used for the assessment of URM
structures in every day practice. Therefore, since 2018, the Block Research Group has been
working on “Practical Stability Assessment Strategies for Vaulted Unreinforced Masonry
Structures” with support of the Swiss National Science Foundation (SNSF). The goal of this
research project is to create tools suitable for everyday engineering practice and to develop
appropriate analysis strategies for diverse contexts and circumstances related to the
availability of time, budget and available data. The main outcome is COMPAS Masonry: an
open-source, Python-based computational framework for the assessment of URM structures.
It provides a general purpose toolbox for working with assemblies (compas_dem) and three
custom made open-access solvers that can deal with different aspects of the assessment of
masonry structures: compas_tna based on Thrust Network Analysis, compas_prd based on
the Piecewise Rigid Displacement method, and compas_rbe based on the Rigid Block
Equilibrium.

Comparison of Two Different Approaches for the Seismic Evaluation of the Bonet Building of the National Palace of Sintra, Portugal

Scipedia content — Tue, 30 Nov 2021 14:17:09 +0100

Complex masonry monuments represent an important part of the built cultural
heritage and most of them are vulnerable to seismic actions. Their large scale, irregularity,
and heterogeneity makes it challenging to characterize their structural behaviour.
This work addresses the state of conservation as well as the structural behaviour and
seismic vulnerability of the most ancient body of the National Palace of Sintra, Portugal:
the Bonet building. This body was built on top of Arabic foundations during the reign of
King Dinis, around the year 1281, and since then few alterations were made to the building.
In order to minimize the multiple uncertainties usually existing in complex masonry
buildings, whether related to geometry or masonry mechanical properties, a detailed structural
survey was conducted together with different in-situ experimental tests. All the tests
performed were important to the adequate characterization of the building and the
calibration of the numerical models. The final values adopted for the mechanical properties
of the rubble stone masonry are presented and can be used as a reference for future works in
ancient Portuguese monuments of the same period.
Afterwards, nonlinear static analyses were performed in two different software (3MURI
and ABAQUS). Comparisons and discussion of the results are made. The differences in
modelling strategies and characterization of materials between the two software are considered
with regard to their realism, computational effort, data availability and applicability to large
scale structures. Efforts to calibrate and obtain the same behaviour of the building for the
different software were made, involving geometry, boundary conditions and
characterization of the material constitutive laws.

Comparison Methodologies and Intervention for two Masonry Churches Affected after the 2017 Earthquake in Mexico

Scipedia content — Tue, 30 Nov 2021 14:17:01 +0100

The current state of two 16th century masonry churches were studied after being
damaged during the 2017 earthquake in Mexico. The two complexes being analyzed are part
of the World Heritage Site “Ruta de los Conventos”: the Convento de San Guillermo
Totolapan, in the state of Morelos south-east of Mexico City, and the Huaquechula Monastery,
in the state of Puebla south of Mexico City. These buildings are representative of the
architectural model adopted by the first missionaries who evangelized the indigenous
populations in the 16th century. The churches were constructed circa 1535 and 1548,
respectively. The history and cultural significance for each project is researched in
coordination with the stakeholders, along with the contrasting structural systems and any
known previous interventions, historic and contemporary.
The damage inflicted to the two churches due to the most recent earthquake (2017) is critically
analyzed, specifically focusing on inherent defects of the existing materials, the variation in
construction methodologies and the impact of contemporary interventions such as the use of
reinforced concrete and structural steel following previous earthquakes. Potential repair
methodologies are discussed in order to mitigate future damage to the structures. Discussions
include the importance of using compatible materials along with appropriate repair procedures
and the need for ongoing maintenance of these important heritage structures.

Comparison Between Investigation Techniques for the Evaluation of the Compressive Properties of Brick Masonry Structures

Scipedia content — Tue, 30 Nov 2021 14:16:53 +0100

Existing masonry buildings, representing a large portion of the building stock in the
Mediterranean area, are usually characterized by the presence of different constituent
materials. The modifications experienced over time could have modified the static
configuration of the structures and could trigger local damages and crises. Therefore,
it is of fundamental importance to assess the safety of these constructions and to
determine if retrofitting interventions are needed. In this framework, one of the crucial
aspects is the mechanical characterization of masonry. Concerning brick masonries, several
testing methodologies exist for the determination of the compressive strength, the elastic
modulus and the Poisson’s ratio. In particular, slightly-destructive tests, such as double
flatjack tests and compressive tests on masonry cores, can be performed in place of
destructive tests due to their limited invasiveness. However, they could be less
representative of the overall behavior of masonry structural elements. The objective of the
research is to evaluate the reliability of slightly-destructive tests in evaluating the compressive
properties of masonry. An experimental campaign is presented, in which masonry specimens
were built to reproduce a poor-quality brick masonry typology. Standard compression tests
on wallets and double flatjack tests, both monotonic and cyclic, were performed.
Moreover, masonry cores were extracted from the masonry specimens and tested in
compression. Compressive strength, elastic modulus and Poisson’s ratio were evaluated
from each testing methodology. The results obtained from the double flatjack tests and the
tests on cores, in terms of strength and deformability properties, were compared with the
results of the standard compression tests, taken as reference. Correlations between the
results of the slightly-destructive tests and the standard compression tests were established,
obtaining a good agreement and confirming that the experimental techniques can be
reliably adopted for the evaluation of the compressive properties of brick masonry.

Combined Shear-Flexural Verification of in Plane Loaded Reinforced and Unreinforced Masonry Walls

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

The safety verification of in-plane loaded masonry panels requires the
evaluation of at least three different collapse conditions connected with overturning, shear
sliding, and shear – compression failure at the panels’ toe. In reinforced panels, the resisting
models should even take into consideration the presence of localized or distributed
reinforcement.
In general, the masonry is considered a Mohr-Coulomb type material not resisting tension
and plastic in compression, while reinforcement is a brittle elastic material resisting
tensile forces only [1].
The ultimate limit state is however linked with a given subset of compressed material
inside the panel area. The compressed sections are therefore varying inside the panel as a
function of the applied load. The collapse occurs in shear or overturning when one peculiar
compressed section reduces to its minimum [2].
By equating the capacity in shear and overturning it is possible to derive an explicit
statement of the minimum length of the compressed section which will be activated by a
simultaneous failure in shear and overturning. A simple inequality is detecting the real failure
mode and this allows directly computing the failure load resultant.
The procedure is very fast and can deal even with localized or distributed reinforcement
layers such as fiber strips or mesh reinforced mortars.
Some examples of panels discussed in the literature show the effectiveness of the
proposed verification procedure.

Collaborative Use of DEM and FEM for Brick Joint Splitting in Strong Earthquake Ground Motion

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

Masonry structures constructed about one hundred and fifty years ago, in the era
of the opening of Japan, have been recognized as industrial heritages. Many of them are
masonry warehouses made of brick or stone walls framed by wood members. In this research,
a two-story warehouse in Tomioka city, a mortar jointed brick masonry with wooden frame
reinforcements, was studied for strong earthquake ground motion. Several vibration modes
were identified by micro-tremor observations and excitation tests. The three-dimensional FE
overall model was constructed and tuned for the distinctive vibration modes. Two DEM local
models, one for bending at the center bottom of the wall treated by plane strain, and the other
for shear at the upper corner of the wall by plane stress, were constructed to evaluate brick
joint splitting. For both models, dynamic displacement response obtained by the three-
dimensional FEM were specified at their peripheries via periphery blocks. At the center bottom
of the wall, horizontally developing joint splitting in the section was evaluated. At the upper
corners, obliquely proceeding joint splitting on the wall was evaluated. In these analyses, the
specified displacements were calculated by the FE model for intact brick walls, regardless of
the degrading status of the walls. Although this assumption will have to be justified, the results
of DEM were consistent with the reported summary of past earthquake damages.

Claudius Aqueduct in Rome - Kinematic Analyses and Empirical Experiences for the Definition of Structural Restoration Interventions

Scipedia content — Tue, 30 Nov 2021 14:16:27 +0100

Present work summarizes a study on the stability of some parts of the Claudius
Aqueduct in Rome (1st century AD). The project provides empirical applications linked to the
definition of minimal interventions for the structural restoration of a section of the structure
near Capannelle. Results of the kinematic analyzes conducted and of experiment with a physical
model representing the structure of the upper hydraulic conduit (speco) are reported.
Ultimately, hypothetical minimal interventions are outlined for the protection of the structure
and at the same time of the image and usability of the Aqueduct.

Characterization of Historic Mortars for Compatible Restoration: Case Study of South Africa

Scipedia content — Tue, 30 Nov 2021 14:16:18 +0100

The history of the South African construction industry dates as far back as the Castle
of Good Hope (1666), Slave Lodge (1679), Robben Island (1700), Union Buildings (1913),
memorials and cathedrals, among many others. These structures represent the political,
slavery, liberation and religious history of South Africa and its development throughout the
years, while also contributing towards economic growth through tourism. Historical buildings
stand out from the rest of the modern constructions as they portray marvellous architectural
designs and unique materials used for their construction. However, due to ageing and
environmental conditions, they often show critical signs of deterioration, which threaten the
existence of some. In attempts to rescue these national treasures, the use of Portland cement,
which is considered incompatible with the original materials, has become a common practice,
not only in South Africa but abroad. To avoid disparity in materials during repair of historic
structures, original material characterization is therefore recommended. This paper
investigates the effects of Portland cement used on the repairs of historical masonries of the
Castle of Good Hope, Cape Town and buildings on Robben Island, in South Africa. The mortar
samples were collected from the Castle and analyzed using the techniques such as the visual
investigation, cohesion test, microscopic and titration test. It is observed that the original lime-
based mortars are not compatible with the Portland cement produced mortars. It was evident
on the masonry, as the repairs are repelling from the original surfaces on these two structures.

Characterization of Historic Mortar Samples and Period Analysis: A Case Study

Scipedia content — Tue, 30 Nov 2021 14:16:08 +0100

The Imperial Temple in Antiochia Ad Cragum is estimated to be first constructed at the end
of 2nd or start of 3rd century, the time of the Severan dynasty. However, archaeological
evidence also suggests that there were interventions during the Byzantine era, with burials
over the temple platform, a wine press on the northern side, and walls constructed
perpendicular to the temple on the southern side, use of which are unidentified. There is also a
retaining wall in the back of the temple that holds the earth against erosion from the hill on
the back, but it is curiously close to the Temple if built as part of original construction.
The goal of this study is to investigate the authors’ hypotheses of a multi-phase use and to
identify which elements found on the site may be contemporary to each other by comparing the
composition of mortar samples collected from different areas, supplemented by a
geoarchaeological investigation. Five samples of mortar from the various areas around the
temple were collected and tested using three methods: X-ray diffraction (XRD), Scanning
Electron Microscope (SEM), X-ray fluorescence (XRF) and thin section petrographic analyses.
While all mortar samples include similar locally sourced hydrated lime and sand mixtures, three
distinct construction styles are identified in the visual analysis of the building elements, the
mortar analyses, and the geoarchaeological investigations. One sample from the walls of the
wine press pool includes fibers. The unique interdisciplinary work utilizing both material
analyses and geoarchaeology strengthens the conclusions that can be drawn from individual
fields of study and provides more support for the hypotheses of the phased destruction and
changing use of the monument.

Characterization of FRCM- and FRP-Masonry Bond Behavior

Scipedia content — Tue, 30 Nov 2021 14:15:59 +0100

Composites made of fibers embedded in organic or inorganic matrices are efficient
systems for reinforcing historical masonry structures to provide strength and ductility with
a negligible mass increment. As it is well known, the structural performance of the composites
mainly relies on their adhesion to the substrate. There are different methods to test
the adhesion of the composite to the substrate: in laboratory direct shear test is the
most commonly employed, while on-site the bond between the reinforcement and the
substrate is checked by the pull-off test. In this paper, the adhesion of different composites
to the same substrate made of fired-clay bricks is investigated by both the shear test and the
pull-off test to qualitatively assess the difference in the two methods. Additionally, to
investigate whether the bond is affected by the presence of water in the pores, half of the
specimens were tested in water saturated conditions. Three different types of matrix (based
on epoxy resin, natural hydraulic lime and Portland cement) were used for the composite
matrix, without changing the geometry, the type of masonry substrate and the fibers
(galvanized steel cords).

Characterization of Cracks in Historical Buildings Using Image-Processing Techniques

Scipedia content — Tue, 30 Nov 2021 14:15:51 +0100

Cracks are structural pathologies that affect the structural integrity of historical
buildings. The methodologies commonly used to detect cracks are based on visual inspections
or in intrusive techniques that involve removing external wall layers. The main objective of this
study is to develop and validate a semi-automatic and non-destructive tool that helps the user
to analyze the position and growth of the cracks in masonry constructions based on a
photogrammetry analysis. The developed tool uses image processing to plot a curve of the crack
area, and, in case needed, its evolution over time. The tool was validated in laboratory using
earthen samples that were subjected to uniaxial compression tests. The research also provides
the results of the tool used in a case study of a 16th Century stone masonry church located in
the main square of Cusco; Southern Peru. This case study validates the qualitative metrics of
the present work, and indicates that the tool provided accurate results when compared to the
ground truth, which could be helpful in future research studies in order to automatize crack
monitoring.

Challenges in the Reuse and Upgrade of Pier Luigi Nervi‘s Structures

Scipedia content — Tue, 30 Nov 2021 14:15:39 +0100

The paper presents the overall objectives of a funded research program for the
development of a Conservation Plan (CP) for the two halls by Pier Luigi Nervi of the Turin
Exhibition Center. The Turin Exhibition Center was conceived immediately after the Second
World War to host primarily the annual Automobile Show, in connection with the presence in
Turin of the FIAT motor company. The two main pavilions of the Center (Halls B and C) are
outstanding examples of a pioneering use, of new advanced methods in reinforced concrete
construction, combining innovative prefabrication procedures and the re-invention by Nervi of
ferrocement, used to form extremely thin elements. The CP is expected to push and contribute
to the preservation of the halls designed and built by Nervi, with special emphasis on structural
and seismic vulnerability aspects, also due to concerns raised on the durability of concrete
materials and technologies. Re-using these buildings entails the challenge to guarantee new
extended service life to concrete structures built many decades ago and faces the need for a
seismic assessment of these structures, in compliance to recent Italian standards.

Calibration of a FEM Model with Complex Geometry: the Case Study of Santa Maria Maddalena Church in Ischia, Italy

Scipedia content — Tue, 30 Nov 2021 14:15:28 +0100

The technology of the Bourbonic casa Baraccata is one of the earliest earthquake
resisting systems, used since the 18th century across Southern Italy in response to the
disastrous earthquakes that hit the region frequently. The church of Santa Maria Maddalena
in Casamicciola Terme, Ischia Island, Italy, represents one of the very rare examples, with a
unicity lying on the combination of materials adopted. It presents the regular Bourbonic
Baraccato walls in the back portion, and tuff-masonry walls embraced in iron frames in the
main body. The paper aims at presenting the development of a 3D Finite Element Model
(FEM) calibrated taking advantage of ambient vibration tests performed under operational
conditions. Sensitivity analyses allowed to inspect and validate several modeling strategies
and explore the relevance of the data still unknown to define a reliable numerical model to
perform the study on the seismic behavior of the church of Santa Maria Maddalena.

British Colonial Era‘s Religious Built Heritage in Yorubaland, Nigeria: Key Conservation Problematics and the State of Know-How

Scipedia content — Tue, 30 Nov 2021 14:15:21 +0100

Colonial-era buildings’ conservation is now viewed in a more positive light as
part of the urban fabric, however the conservation state of colonial-era built heritage has
received scant research attention. There are major challenges especially for the preservation
of religious buildings erected in the former European colonial territories in the non-
Western world. This paper is the outcome of ongoing fieldwork-based research, which aims
to identify and locate the mosque and church structures built during the British colonial
era in Yorubaland (South Western Nigeria) and investigates their conservation state. This
research adopts a mixed methods approach, employing physical observations and semi-
structured interviews with heritage practitioners. The analysis of the fieldwork data initiates
a discussion on the challenges and threats that result from the spatial requirements of a
growing number of congregations which have lead to physical interventions on the original
fabric, ranging from minor to major modifications and demolitions. The deficiencies in
institutional conservation know-how in addressing the emerging spatial requirements in
theoretically and technically appropriate ways are revealed.

Betang, a Traditional House of the Dayak Ngaju in Borneo Its Space Related to Structure

Scipedia content — Tue, 30 Nov 2021 14:15:13 +0100

The ancient structures of the tribes in the globe yearn to conserve. It marks th eir
races as natives of those places. Nowadays, some of those buildings have lost through natures
and cultures. This study aims to get the pieces of knowledge of the Dayak Ngaju tribe. In a structure that calls as Betang. It formed of bases, cavities, floors, walls, and roofs. As known,
some of these buildings have ruined, only a few of them still stand. The methods of research led to qualitative and descriptive. It is the way to get the results. At first, Betang reviewed
through the critical comparisons of the elements and space backgrounds. Then, took some
points in the hypotheses, once it structures analyzed. With the processed amongst functions,
ties, measures, forms, and its parts fit the old. Hence, the appraisal gave the rest of the
structures formed in percentages. These sums use as conservation values. The reviews were
on the profer Dayak villages sort of Tumbang Gagu, Anoi, Malahoi, and Korik. It gave
samples through sketches, pictures, and some interviews. It helped to finish the research. Study proves that Betang has left 42% off its old structured elements. It is a form that shaped the spaces.

Axial Compression Tests on Rubble Stone Masonry Reproducing Opus Incertum of Ancient Pompeii

Scipedia content — Tue, 30 Nov 2021 14:15:04 +0100

In order to investigate the mechanical behaviour of the typical ancient rubble stone
masonry type at the archaeological Pompeii site, an experimental program was carried out on
masonry panels realized with the aim of reproducing the ancient technique opus incertum.
Three panels (1.20m x 1.20m x 0.45m) were realized by using original rock units from ruins
emerged in the excavation works at Regio V at the site and pozzolanic lime-based mortar
realized according to the traditional technique. The first phase of the experimental program
involved the accurate reproduction of Pompeii-like masonry panels and the execution of sonic
pulse velocity tests to be compared with those carried out on original structures at the site.
Thus, three in-situ diagonal compression tests were carried out to derive masonry shear
strength and relevant correlation with sonic velocities. The last phase of the experimental
program focuses on laboratory axial compression tests on five specimens extracted from the
three panels analyzed in the first phase and is herein described in detail. The results of axial
compression tests on two of such specimens in terms of axial compression strength and elastic
modulus as well as the analysis of the crack pattern and failure mode is herein presented and
discussed.

Automated Model Updating of a Masonry Historical Church Based on Operational Modal Analysis: the Case Study of San Giovanni in Macerata

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

Over the past few decades, the conservation and seismic assessment of historical
buildings has gained great importance. In particular, the prediction of the dynamic response
of masonry constructions plays a central role in retrofitting and conservation interventions.
Finite element modelling has become the most common and accessible approach to study the
behavior of complex masonry structures, however, the gap between numerical and
experimental analysis may lead to erroneous results.
This work describes the model updating procedure applied to the finite element model of San
Giovanni’s church in Macerata, condemned in October 2016 after the Central Italy
Earthquake. The laboratory of Proof and Research on Structures and Materials of Roma Tre
University carried out an extensive in-situ testing campaign including geometric survey, video
endoscopy, flat-jack test, sonic tomography and ambient vibrations test in order to investigate
the state of the building. The work involved both numerical and experimental analysis: the
results of the testing campaign were interpreted and correlated with an accurate finite element
model developed with the software Midas Gen. Operational modal analysis was performed in
order to extract the modal parameters of the building (modal frequencies, shape vectors and
modal damping). Material characteristics and boundary conditions were updated according to
the Douglas-Reid method. In the end, the final model was compared to the initial model to
evaluate and discuss the process.

Assessment of Tunneling Induced Damage on Historical Constructions Through a Fully Coupled Structural and Geotechnical Approach

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

The development of urban mobility implies the construction of tunnels, often
interacting with valuable historical structures. It is thus necessary to develop rational and
reliable procedures to estimate the potential excavation-induced damage, dealing with complex
soil-structure interaction problems. Classical approaches are often characterised by relatively
simple schematisations for either one or both components of the problem, as, for example,
springs for the soil or equivalent plates for the structure. Such simplified assumptions prove to
be appropriate for simple soil-foundation cases, while show several limitations when tackling
more complex problems, as those involving the excavation in the vicinity or beneath historical
masonry structure. In such cases, the need for reliable prediction of the potential damage on
surface structures induced by construction activities justifies the adoption of advanced
numerical approaches. These need to be based on realistic constitutive assumptions for both
soils and masonry elements and require the definition of the three-dimensional geometry as
well as an accurate modelling schematisation of the excavation process. In this paper a 3D
Finite Element approach is proposed to model in detail the excavation of twin tunnels,
accounting for the strongly non-linear soil behaviour, interacting with monumental masonry
structures, carefully modelling their geometry and non-linear anisotropic mechanical
behaviour. The work focuses on a specific case-study related to the ongoing construction of the
line C of Rome underground.

Assessment of the Seismic Retrofitting of a Historical Masonry Mosque by means of Nonlinear Dynamic Analysis

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

Seismic actions have been a great challenge for structures in the structural
engineering community, and the need for further developments has been approved by
catastrophic seismic events at each time. Reproducing the dynamic behavior of structures with
an acceptable level of accuracy is a complex task due to uncertainties related to the
geometrical, material and physical structural system, more particularly, in the case of existing
historical masonry structures. The use of dynamic analysis is a better choice than the use of
static or quasi-static approaches since it is a better representation of the dynamic response of
a structure by taking account of its energy dissipation capacity. The scope of the present paper
is focused on a seismic assessment of a historical masonry structure, Kütahya Kurşunlu Mosque
located in Turkey, before and after it has been retrofitted. The historical mosque is located in
a seismic prone zone where it is crucial to ensure seismic safety of structures and the local community. Based on the condition of the structure reported from the site inspections, a seismi
retrofitting by using steel girder elements was implemented on the structural load-bearing
walls. The effectiveness of the seismic retrofitting to the seismic response of the mosque was
investigated by means of the finite element method. Three bi-directional nonlinear dynamic
analyses were performed by using real ground motion records aiming at the validation of the
nonlinear dynamic response of the numerical model in terms of damage patterns, and
demonstration of the contribution of the seismic retrofitting by comparing the representative
model with its retrofitted counterpart. The comparison has been carried out in terms of peak
displacement and damage patterns. It is found that the contribution of the seismic retrofitting
is considerable for the out-of-plane displacements of the load-bearing walls. Furthermore, a
good correlation between existing damage and the numerical damage is achieved, and,
therefore, the validation of the nonlinear response of the representative model is attained.

Assessment of Structural Damage and Evolution in Time in Historical Constructions Using Numerical Models: the Case of the Church of Saint Bassiano in Pizzighettone, Cremona

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

This paper investigates the capability of advanced numerical modelling techniques
to simulate experimental observations as damage or deformations in complex masonry
structures. The case of the church of St. Bassiano in Pizzighettone, Cremona Italy is chosen.
A multidisciplinary research was set up to collect data as geometric survey with Lidar
technology, measurement of axial force in the iron tie rods of the nave, and a monitoring system
for crack widths. The data was used as an input to develop and validate a finite element model
to study the structural damage and the evolution of the building in time.
The finite element model features a three-dimensional geometry, which is created in part
automatically, taking advantage of a parametric model for ribbed masonry vaults, proposed
recently by the authors. The FE model results in close adherence with the real building
structure, due to the accuracy of the collected data. The simulation model features a continuum
plastic damage model to take into consideration the masonry constitutive behaviour.
The results show how the system response is closely related to the structural evolution in
time, associated with the dismantling of the chapels on the south side and the addition of the
iron tie rods in the nave. The numerical simulations highlight also the important effect of the
soil settlements in the present crack pattern. The information obtained using this approach will
allow to understand the active mechanisms in the building and to optimise the technical
interventions in critical parts of the structure.

Assessment of Seismic Fragility of Historical Buildings at the Urban Scale by Typological-Mechanical Approaches: the Case Study of Foggia

Scipedia content — Tue, 30 Nov 2021 12:53:05 +0100

The study of the seismic vulnerability of historical centres, especially in the Mediterranean zone, is one of the main issues in ongoing scientific research. This is due, on the one hand, to the continuous evolution of the seismic demand and, on the other hand, to the high vulnerability of the masonry existing building stock. The seismic events of the last few years highlighted the necessity to perform a large-scale survey of the huge amount of masonry buildings in historical centres, in order to provide prioritization scales for planning mitigation strategies. With this regard, the scientific literature provides several methodologies that allow a rapid assessment based on pre- defined survey forms. The data obtained from the surveys are usually used as the input for algorithms aimed at estimating the vulnerability level of the building investigated. The aim of the present work is to propose a general framework for analysing seismic vulnerability of masonry historical centres and deriving fragility curves basing on multiple data sources. In particular, using data collected through existing territorial databases, supplemented by a set of vulnerability forms available for the city centre of the Municipality of Foggia, Southern Italy, some vulnerability classes are defined. Based on the mechanical and geometrical features identified for each class, several ideal and representative buildings are generated, and their seismic behaviour is investigated through the variation of significant parameters. At the end, the capacity of the buildings is evaluated by performing simplified nonlinear analyses and, subsequently, by estimating the damage level of the sample through the definition of regional fragility curves.

Assessment and Monitoring of Historical Timber Construction: Available Tools to Support Decision-Making Processes

Scipedia content — Tue, 30 Nov 2021 12:52:57 +0100

Timber structures represent a rich although still underestimated portion of the historical built asset worldwide documenting a tradition of sustainable practices and craftsmanship. Assessment of their condition is a fundamental step towards their conservation. While some overarching approaches for the assessment of timber structures are not dissimilar to those used for other types of structures, there are some specific factors affecting timber structures behavior that should be taken into consideration. Such factors are especially related to the organic nature of wood, which makes timber’s properties largely variable and influenced by the environment. Successful conservation of historical timber structures requires combination of many different disciplinary contributions, from wood science and technology, to structural engineering, building physics, architecture, art history and environmental science, among others. This contribution aims to present an overview of tools supporting decision-making processes for the assessment and conservation of existing timber structures, including both methodological frameworks and technical approaches for data collection and analysis. These tools are reviewed according to the scope of the assessment and considering multiple levels at which timber structures are studied, at the material, system and building scale. Additionally, emerging approaches and challenges for holistic assessment of historical timber structures are discussed.

Assessing the Impact of Seismic Risk Mitigation at the Urban Scale on Community Resilience and Housing Recovery

Scipedia content — Tue, 30 Nov 2021 12:52:50 +0100

European historical city centers are particularly prone to natural disasters. This is due to the fragility of structures that often times do not comply with seismic codes; the high constructions’ density that causes induced damage; and the historical relevance of buildings that makes difficult the enacting of mitigation strategies. In Italy, major earthquake caused extensive damages over the last century. Seismic events have a huge impact on the nation’s economy growth due to direct and indirect impacts, such as for example the high reconstruction costs or the business interruption spread out over a long period, respectively. In addition, the duration of recovery can affect the population wellbeing and cause permanent displacement. For this reason, the preventive planning of disaster management strategies are crucial to mitigate the damage and enhance resilience. Proposed strategies have to be effective and economically sustainable. In this paper, two towns affected by the 2012 Northern Italy Earthquake are chosen to analyze the reconstruction process. Using information published on the town journal, relevant aspects of the community resilience are highlighted. In particular, the housing recovery, i.e. the return of displaced people to a permanent housing solution is investigated. Then, a suite of seismic mitigation strategies is proposed for both cities, taking into account the peculiarity of the built environment and the damage distribution available thanks to the post- event buildings’ inspection. The effectiveness of the proposed strategies is assessed through a cost-benefit analysis, highlighting optimal solutions to reduce the economic and social losses.

Assemblability Constraints in the Limit Analysis of 3D Masonry Interlocking Blocks

Scipedia content — Tue, 30 Nov 2021 12:52:42 +0100

This paper presents a method to analyses the structural feasibility and assemblability of the masonry assemblages composed of interlocking blocks. Interlocking blocks with projections and depressions on their faces have relatively better structural performance comparing to the conventional blocks with flat faces, during and after the construction. Therefore, they can represent proper alternatives to the conventional blocks for the seismic retrofitting of unreinforced masonry structures. Structural soundness and assemblability of a model are both functions of the interlocking block geometry. The proposed methods enable the designer to adjust the shape of the interlocking blocks, while meeting the structural and assembling requirements. The paper first introduces an extension of the limit analysis to the assemblages with corrugated interlocking interfaces having anisotropic sliding behavior. Then, the work reformulates the extended limit analysis to develop a method to measure the structural infeasibility due to the lack of sliding resistance at the interlocking interfaces. This is called sliding infeasibility and the designer can minimize it during the shape exploration. Finally, an assemblability method is presented to check if the designed interlocking blocks can be assembled on the other blocks in contact. This method is added to the extended limit analysis and the sliding infeasibility measurement method in form of a geometric constraint that prevents modeling of un-assemblable structures.

Application of Geophysical Prospecting Methods for Soil Structure Characterization of the Cathedral of Santo Domingo, Dominican Republic

Scipedia content — Tue, 30 Nov 2021 12:52:34 +0100

Hispaniola is in the edge of interaction between the North American and Caribbean plates. In this zone, the occurrence of earthquakes greater than 5.0, Mw is frequent, characterizing it as a seismically active zone. These earthquakes cause considerable material damage and can provoke loss of human lives. The Cathedral of Santo Domingo, Primate of the Americas, is in the Colonial City of Santo Domingo. It is the most important colonial building in Dominican Republic, was built between 1521-1541, and is a masonry building made with stone ashlars and covered with stone ribbed vault. However, it is essential to know about the possible seismic behavior that the ground could have in case of a relevant earthquake to try to avoid possible damage to this heritage. For this reason, the aim of this research is to apply geophysical prospecting methods for the seismic site characterization of the Cathedral of Santo Domingo. For this study, the geophysical methods applied were: MASW (Multichannel Analysis of Surface Wave), H/V Spectral Ratio and Georadar. The characterization of site conditions was determined with the values of the average shear wave velocity for the top 30 m of soil (Vs30) obtained with the MASW method. As a main result it was found that the site seismic class determined with the MASW method was type C- very dense soil and soft rock (360-760 m/s), according to the NEHRP classification. In addition, the Georadar tests allowed confirming that there are no unknown caverns in the basement of the Cathedral in the first 5 m, thus it is accepted as valid the seismic classification of the soil obtained by the MASW method.

Applicability of FEM and Pushover Analysis to Simulate the Shaking-Table Response of a Masonry Building Model with Timber Diaphragms

Scipedia content — Tue, 30 Nov 2021 12:52:26 +0100

The seismic behaviour of unreinforced masonry (URM) structures is generally governed by a complex interaction between the out-of-plane and in-plane responses of the walls, depending on the in-plane stiffness of floor/roof diaphragms and the efficiency of wall- to-floor/roof connections. The presence of timber diaphragms, which are typically characterised by low in-plane stiffness and poor connection to the masonry walls, adds challenges to the numerical modelling and analysis, as well as to the structural assessment of URM structures under seismic actions. This work aims at investigating the applicability of refined FE modelling using macro-modelling approach and mass-proportional pushover analysis for simulating the response of URM structures with flexible diaphragms, comparing the results with experimental data obtained from incremental dynamic testing. A full-scale two-storey prototype building with timber diaphragms, which was tested in shaking table at the European Centre for Training and Research in Earthquake Engineering (EUCENTRE), in Italy, was considered to perform this study. A refined finite element (FE) model was developed in DIANA software, considering the wall-to-diaphragm (WTD) connections. While the strength values of masonry were adopted according to axial and diagonal compression tests, the modulus of elasticity was calibrated after simulating in-plane cyclic shear tests of masonry piers, which were part of the same experimental program at EUCENTRE. Recommendations from international guidelines were used to derive the assumed material properties for diaphragms and wall-to-diaphragm connections. Mass-proportional pushover analysis was performed and a comparison between numerical and experimental results is presented to investigate the assumptions, advantages and limitations of the presented numerical modelling and analysis approach.

Anchorage of Reinforcement Bars in Hennebique R.C. Structures

Scipedia content — Tue, 30 Nov 2021 12:52:19 +0100

The Hennebique system was the most successful among the patented systems in the pre-code period even though the design rules were not completely clear. Anchorage of the re- inforcement is one of these unknown aspects and how it was calculated, and if it was calculated at all, is still today not clear. For this reason, the efficiency of the anchorages is one of the major issues when dealing with retrofitting a Hennebique structure or when its safety needs to be evaluated. In this paper a series of tests have been performed on the typical Hennebique an-chorages for reinforcing bars (fish-tails) and for the plate stirrups (bended ends) that were used. Different concrete types have been used so that either the collapse mechanisms of the anchor-ages and their ultimate strength may be identified.

Analysis and Assessment of Swedish Vaulted Masonry Structures Using Funicular Methods

Scipedia content — Tue, 30 Nov 2021 12:52:11 +0100

Practising structural engineers working with historic masonry structures need access to further developed methods to analyse and assess the structural behaviour of masonry vaults. The aim of this study is to evaluate methods to analyse vaulted masonry structures and to develop a methodology for the application of suitable methods to the work of practising structural engineers. A secondary aim is to use the methods studied to analyse and assess the structural behaviour of three Swedish church buildings of different types and with vaulted structures. The churches are Gökhem church, a small parish church built in the 12th century, and the Lund cathedral, also built in the 12th century; both originally in the Romanesque style but with later alterations. The third church is St Johannes church in Stockholm, built in the neogothic style in the late 19th century. The methods used are parametric graphic statics of thrust line analysis and Thrust Network Analysis (TNA), both based on funicular analysis. The results show the strength of using such methods to assess and evaluate the structural behaviour of historic vaulted masonry structures. They provide a pedagogical description of the structural behaviour of masonry vaults and the conditions that affect their load-carrying capacity. Another result is the implementation of a method to perform the analysis in a feasible and effective way. For the analysed church buildings, the results provide an understanding of their structural behaviour and clearly show how different variables affect the magnitude and impact of the thrusting force. Thrust Network Analysis has great potential to become a very effective method to perform advanced 3d analyses of masonry vaults but needs to be developed in order to enable “best fit solutions” to map the thrust network to the shape of the existing vaults. Such methods are under development.

An Interdisciplinary Approach for the Experimental Assessments of the Seismic Safety of Artworks

Scipedia content — Tue, 30 Nov 2021 12:52:03 +0100

Recent seismic events occurred in areas rich of ancient remains and full of cultural and artistic heritage in terms of artworks. Earthquakes may damage buildings, but the vibrations may also induce the uplift and overturning of their content, implying irreparable loss of cultural values. The seismic assessment of objects is usually tackled modelling them as rigid blocks. This paper focuses on statues, which generally present a very complicated geometry, and proposes a general methodology involving different disciplines, for their experimental seismic assessment. The methodology is here applied to the masterpiece of “Paolo Orsi” museum in Syracuse (Italy), that is the “Venere Landolina”. Due to the complexity of statues, traditional techniques cannot be considered reliable for a proper geometry reconstruction; therefore, Terrestrial Laser Scanner (TLS) and Unmanned Aerial System (UAS) technologies are here employed to obtain a highly detailed and complete digital model. Aiming at providing a low-cost scaled physical model of the statue, a wooden specimen has been arranged employing a Computer Numerical Control (CNC) milling machine, cutting off disks from flat panels which are then superimposed and glued, progressively reconstructing the actual geometry of the statue. The specimen, able to approximately reproduce the scaled actual geometry, was then tested on a shaking table with ground motions compatible with those expected for the site where the statue is located. The obtained results are finally correlated with those expected for the real scale statue.

An Integrated Modeling Approach that Combines Elastic Amplification and Rocking Analysis for Seismic Assessment of a Masonry Tower

Scipedia content — Tue, 30 Nov 2021 12:51:55 +0100

Failure of masonry structures during earthquakes often occurs via specific, well- documented collapse mechanisms, many of which involve partial collapse of the structure well above ground level. Consequently, the elastic response of the structure needs to be considered, which in the case of historic structures such as bell towers and churches often requires modal analysis using finite element models - the generation of which can be labour-intensive and time- consuming. This paper presents a new integrated modeling approach which combines finite element analysis with rocking dynamics in order to model the seismic response of complex structural geometries in a computationally-efficient manner. The modeling strategy is implemented within COMPAS - an open-source computational framework that provides geometry processing independent of CAD software, and is incorporated within the broader framework of a tool being developed for the seismic collapse assessment of masonry structures. The framework of this new tool is first outlined, and the utility of the new modeling approach then demonstrated through application to the seismic assessment of a historic masonry tower in North-Eastern Italy. The analysis results indicate that for the level of seismic hazard expected on site, failure of the tower is most likely to occur via overturning collapse of one of the rampart elements. The importance of accounting for elastic amplification effects, as well as the influence of varying boundary conditions on the dynamic response, is also demonstrated.

An Innovative Shell Structure in Codogno (Italy). Evaluation of Structural and Seismic Performance

Scipedia content — Tue, 30 Nov 2021 12:51:48 +0100

The saddle-shaped shells, or hyperbolic paraboloids, often joined together to form a pitched roof or an inverted umbrella, were used by many pioneers in structural architecture, such as Félix Candela, which introduced a very innovative use of reinforced concrete in thin layers or together with some reticulated ribs. An innovative semi-prefabricated building system was developed in Italy in the years ’30 of XX cent by a very active brick factory near Piacenza, RDB: the SAP system, that allowed building curved surfaces by prefabricating light elements. After WW2, this technique was applied also for the new structures covering wide spaces for the developing industry or also for public leisure, using prefabricated panels of the desired length. A particularly interesting application was the BISAP (double-SAP) panel that could be adapted for building large shells. In Codogno (LO), Italy, the BISAP panels were employed to cover a large sports hall, spanning about 37 × 26 m, without intermediate supports, resting (mainly) on the four corner pillars. Border pitch beams sustain at the top two crossed beams that separate (and support) the four hypar fields. On the four sides, two rafter beams are connected by horizontal prestressed tie beams, in order to minimize displacements and assure the preservation of the original shape. The first aim of the structural analysis was to assess the static conditions of the roof under the service loads assigned by Italian code for SLS, and then to evaluate seismic vulnerability at ULS of the whole sports hall, being a public space subjected to particular safety provisions. The FE code used (Straus7) allowed a very careful discretization of the orthotropic slab with the correct inclination and twist of the ribs, giving a reliable forecast of the behavior also in seismic conditions: the dynamic analysis of the modal shapes gives a satisfactory response of the shell, which maintains nearly unchanged his shape during free vibration modes. The seismic safety of the structure can be then increased by simply augmenting the stiffness of the four corner supports, where shear action is concentrated, by adding ribs to the L-shaped sections to form cross shaped ones. In this way also the slenderness (and weakness) of additional intermediated pillars could be overcome.

An Example of Fit-for Purpose Use of Materials in Roman Architecture: P Temple, Side, Antalya/Turkey

Scipedia content — Tue, 30 Nov 2021 12:51:40 +0100

The high-podium Roman Period temple, with a semi-circular plan scheme, was
discovered by Lanckoroński and his team in Side, Turkey and named after ‘P’ in 1890 [1].
The temple was unearthed by Mansel [2] and his team in 1947 through archaeological
excavations. In 2013, further studies started on the temple. The aim of the still ongoing work is
to seek answers to such issues that haven’t been clarified yet, as the plan scheme, to whom it
was dedicated, and the date of construction.
In this context, the construction structure of the Temple P was investigated during the present
study based on in-situ and precise documentation: At least five different types of stones were
classified by purpose, including conglomerate, travertine, sandstone, marble and rubble stone
mixed with mortar as infilling material. It was seen that fit-to purpose use of the material was
considered more important than the ideal and repeated dimensions of the building blocks.
Moreover, local material was used except for the outsourced marble.
In addition to the large-sized clamps and dowels in the load-bearing core blocks of the
walls, the spaces between the coatings and the load-bearing core were filled with mortar.
In this construction technique, opus revinctum and opus caementitium were used
together. The partition walls separating the three rooms of the lower floor and the vault
cover made with mortar and formwork system belong to the construction period of the
temple. However, there are indications that the outer walls, about 2,5 m thick, originated
from the foundations of a precursor structure. Four construction stages of the pillar profiles of
the orthostat coating blocks of the podium, each having different lengths, can be
traced from the upper surface workmanship, without scalping. The podium, which is
approximately 2,30 cm high, is reached by one main and two side stairs. Numerous, high
quality marble blocks in front of the cella on the podium indicate the presence of a
monumental entrance structure made in opus revinctum technique. Unlike the profiled
orthostat blocks of the podium, which were processed in situ after assembly, the cassette
and cornice blocks of the entrance structure were produced 'on the ground' previously. The
restitution of the marble cassette ceiling of the monumental entrance structure has been
developed by combining the 1:10 scale precision surveys of the blocks via a computer aided
method. The efforts for a modular planning and production are witnessed in the construction
of cassette ceilings.

Amazonas Theater Architectural Construction and Restorations History

Scipedia content — Tue, 30 Nov 2021 12:51:33 +0100

Built in the artistic splendor that prevailed in the late 19th century, Amazonas Theater is considered the most significant architectural construction of the so-called golden age of rubber, both for the values applied in its construction and for the symbolic importance it assumed, that is, the man's victory over the jungle, financial prosperity and the alleged artistic-cultural effervescence. However, when compared to the millenary constructions of the Ancient World, Amazonas Theater can be considered a “baby” and therefore a source of knowledge to be explored. In this sense, this paper intends to be the first one of a series of other ones that intends to study the behaviour of this structure. The paper is focused on describe the history of the construction of the Amazonas Theater highlighting the structural solution adopted to overcome the logistical challenges faced by a construction carried out in the middle of the largest tropical forest in the world and the main interventions performed during its 123 years. To this end, the building records of the Theater, an indispensable documentary source of the building's history, were consulted.

Advanced Tools for Fast Micro-Modelling of Masonry Structures

Scipedia content — Tue, 30 Nov 2021 12:51:24 +0100

Among all the approaches commonly used to study masonry structures, micro- modelling is the most accurate. Masonry can be seen as a composite material made of bricks and mortar joints. Their different mechanical properties, their geometry and their arrangement inside the micro-structure, lead to very complex behaviours that are often difficult to represent using equivalent homogenous constitutive models commonly available in commercial and research FEM solvers. Micro-modelling can capture the complex non-linear behaviours of masonry by explicitly modelling the micro-structure inside the computational model. Micro- modelling leads to models with a large number of finite elements, thus increasing prohibitively the computational time. This is also due to the problem of solving complex nonlinear solutions involving damage and strain localization, leading to very small time-steps required to achieve convergence. Another issue with micro-modelling is the increased complexity in generating the finite element mesh with all the details of the micro-structure. This work presents some advanced tools that can decrease the high computational time required by micro- modelling. A 2-parameter tension-compression plastic-damage constitutive model is presented as an extension of an existing model previously formulated by some of the authors [1,2,3]. The model is implemented in the open-source FEM code OpenSEES [12] with the IMPL-EX method [5], a mixed implicit-explicit integration method that renders the response of this constitutive model step-wise linear, thus removing the convergence issues typically encountered when dealing with softening responses. This research also presents a tool implemented in the STKO (Scientific ToolKit for OpenSees) pre- and post-processor [4] able to automatically convert a homogeneous CAD geometry of a building into a micro-model.

Adaptative Pushover Analyses of a Heritage Structure: Application to a Multi-Tiered Pagoda Temple

Scipedia content — Tue, 30 Nov 2021 12:51:16 +0100

The present paper discusses seismic behaviour of multi-tier pagoda temple. The seismic behaviour was examined by different pushover analysis techniques including adaptive pushover analysis. The case study objective is a five-tier pagoda. The studied pagoda is built of timber frameworks and masonry walls. Masonry is composed of burnt solid bricks and earthen mortar. The pushover analyses are conducted, taking into account frictional behaviour between timber and masonry. The research challenges two tasks. A first task deals with experiments on interface behaviour between timber and masonry in earthen mortar. The study of the discussed interface behaviour is not straightforward since few tests have been conducted on similar subjects. In the present study, direct shear tests are performed. A second task coves pushover analyses of the five-tier pagoda by means of FE analysis. The paper provides useful experimental data of interface behaviour between timber and masonry in earthen mortar and also suggests efficient strategies of seismic assessment of pagoda-type structures.

Adaptation of a Mid-Nineteenth Century Representative University Building to Office Functions

Scipedia content — Tue, 30 Nov 2021 12:51:08 +0100

The rehabilitation of historical buildings plays an important role in enhancing the sustainable built environment of a city. Re-use of old buildings when adapting them to new functions has become a common way to protect the significance of historical buildings and keep them for future generations as examples of the achievements of former architects and construction masters. Issues connected with the adaptation of an old university three-story building from 1866 that has exceptional artistic qualities is the subject of the analysis presented in this paper. Originally, the building was multifunctional, and intended for the activities of various university units. During the II World War, the main body of the building was seriously damaged. After the war, the building was reconstructed using the current building materials and construction solutions, and was handed over to the Medical Department of Wroclaw University. The building is now undergoing renovation, the purpose of which is to change its function into an office building. The greatest value of the building is its façade - with excellent proportions - which perfectly fits into the spatial context and the development of this part of the city. For this reason, the preservation of the building's main structure was the most important aspect of the renovation design process. The paper presents the results of the assessment of the building’s technical state, analysis of the planned functional changes and renovation ideas, and finally, a description of the structural and constructional solutions adopted to solve the problems occurring during the renovation works.

A User-Friendly Digital Tool for the Structural Assessment of Historic Domes: The Case Study of Saint Peter in Rome

Scipedia content — Tue, 30 Nov 2021 12:51:00 +0100

This paper presents a digital tool for the rapid structural assessment of historic masonry domes. It is especially suited for masonry domes that present long meridian cracks, ergo each partitioned element governed by a pushing failure mode. The proposed procedure considers a Heyman’s no-tension mechanical model has been implemented within a commercial user-friendly visual programming environment. The numerical approach consists of a parametric modelling of the failure mechanism and, therefore, exploring the domain of possible solutions using the theorems of the limit analysis. Hence, a heuristic search method is subsequently adopted to refine the geometry of the collapse mechanism and to compute the value of the horizontal trust. The validation of the developed approach has been achieved considering the Saint Peter’s dome. As reported in the literature, the behaviour of the Saint Peter’s dome gradually shifted from a rigid shell-type – stiffened by hoop stresses –, towards a pushing type of dome partitioned by long meridian cracks. The study also evaluated the structural integrity of the drum. In converse with more time-consuming and advanced methods of analysis, the present procedure allows the users to perform a structural assessment of a historic masonry dome in a fast and computationally efficient manner. The developed digital tool will be freely available from a web archive hosted by the University of Minho and, therefore, easily able to reach students, researchers and structural engineers.

A Study of the Historical Construction Technology of Bell Towers in Cyprus

Scipedia content — Tue, 30 Nov 2021 12:50:53 +0100

This paper aims to present the historical construction technology of churches’ bell towers in Cyprus, starting with the initiation of their use and addressing the development of their distinctive morphology adapting and mixing various architectural styles. Traditional bell towers are tall and slender unreinforced masonry structures that are known to be particularly vulnerable to earthquake actions encountered in seismogenic regions, such as Cyprus. Therefore, iron and wood elements with high tensile capacities were commonly utilized in Cypriot bell towers in the form of ties. In particular, the bell tower of Saint John’s church in Psevdas village was constructed using such technology and is an example case studied in more detail in the present work. This tower suffered a partial collapse during an earthquake on May 12th, 2016 and underwent restoration within the next year. Based on the knowledge gathered from the case of the damaged tower and the visual inspection of other bell towers in Cyprus, the use of timber and iron ties in these masonry structures is deemed to be essential for their protection from seismic actions.

A Simplified Modelling Approach for the Practical Engineering Assessment of Unreinforced Masonry Structures Using Layered Shell Elements

Scipedia content — Tue, 30 Nov 2021 12:50:45 +0100

Unreinforced Masonry (URM) has been extensively used as a construction material in mass structures with predominant compression load paths. Despite its reasonably established performance under gravity actions, it can be quite vulnerable to seismic loading, predominantly due to its limited tensile strength and associated quasi-brittle failure modes. Therefore, a reliable seismic assessment of URM structures, including heritage buildings, is vital to ensure life safety and minimise their risk of collapse. This can assist in implementing effective remedial measures, if required, to ensure desirable performance level in future events. Despite significant advancements in masonry research, practical assessment of URM has always been a challenge for structural engineers due to the complexity of the mechanics and geometry involved. Different modelling approaches have been trialled so far, which are typically based on equivalent frame, discrete and continuum elements in 2D/3D domains. In this paper, a simplified nonlinear model is introduced within the framework of conventional layered shell elements, which can be easily implemented in commonly used FE packages, e.g. ETABS and SAP2000. In this model, the URM shell element comprises three layers accounting for cohesion and axial-frictional behaviour parallel and perpendicular to the bed joints, where the mechanical properties can be adjusted for various masonry configurations. The performance of the proposed model is validated against several experimental tests available in the literature, where a good correlation with test data is achieved across various design scenarios and loading conditions.

A Simple and Effective Rigid Beam Model for Studying the Dynamic Behaviour of Freestanding Columns

Scipedia content — Tue, 30 Nov 2021 12:50:37 +0100

In this work, a simple and effective Rigid Beam Model is proposed for studying the dynamic behaviour of ancient freestanding stone columns. As well known, monolithic and multi-drum freestanding columns are historical structural elements typical of ancient temples that still can be found in the Mediterranean area. These columns are particularly prone to collapse in case of seismic actions. The dynamic behaviour of freestanding columns has been studied by many authors in the past [1-3], and it is characterized by a strong nonlinearity due to sliding and rocking between the drums. The Rigid Beam Model here described assumes each drum of the column as a rigid beam element and each interface between the drums as a node of the model able to move horizontally. Similar to Housner [1] approach, this model assumes small displacements and no sliding between blocks. Furthermore, the material nonlinearity is considered by means of a moment-rotation constitutive law slightly modified with respect to the bilinear one introduced by Housner. Numerical simulations were performed on monolithic and multi-drum columns modelled using the proposed Rigid Beam Model approach. Results are compared against simulations of the same columns undertaken by means of the Discrete Element Model, which is able to consider large displacements and the possible sliding between the drums, and it has already proven its effectiveness in simulating column behaviour [2-4].

A QGIS Plugin for the Seismic Vulnerability Assessment of Urban Centers: Application to the City of Popoli in Abruzzo (Italy)

Scipedia content — Tue, 30 Nov 2021 12:50:28 +0100

Seismic vulnerability assessment of buildings is a process of paramount importance for identifying those areas in a city demanding higher attention with respect to potential earthquake attacks. Methods for evaluating seismic vulnerability require a more or less accurate survey of the buildings geometrical and mechanical features, as well as of the structural systems, in order to identify the vulnerability classes to which they belong. However, even for relatively small-sized cities, the task of deriving vulnerability maps may be truly time consuming. Therefore, the development of automatic tools for mapping vulnerabilities of urban areas is necessary to reduce this effort significantly. QGIS (www.qgis.org) is a free open source software which includes a large number of peculiar packages, that make it a powerful tool and that can be well integrated or adapted with new components or plugins. In this paper, a plugin for assisting in the generation of vulnerability maps of an urban area is shown. The presented QGIS tool is applied to a case study, the historic city centre of Popoli, in the Abruzzi region (Central Italy), which belongs to a relevant earthquake-prone area and that was affected by two major seismic sequences in 2009 and in 2016-2017. Potential damage scenarios are presented and discussed, deriving useful information that could be applied in risk mitigation strategies.

A Protected Landmark Monument: Reinforcement, Rehabilitation, and Restoration of the Cathedral Basilica of Manizales

Scipedia content — Tue, 30 Nov 2021 12:50:20 +0100

The Cathedral Basilica of Manizales is one of the most representative buildings of the so-called "republican architecture", boosted in a remarkable and singular way after the fires of the 1920s in the city of Manizales, Colombia. Its "eclectic neo-gothic" design was made in Paris, after the fire that destroyed the city's previous cathedral in 1926. This masterpiece of Colombian architecture turned ninety years old in 2018 after the first stone was laid in 1928. Its construction was carried out in "reinforced cement"; few decades after the appearance of reinforced concrete. During its ninety years, the cathedral suffered earthquakes of high intensity, in 1938, 1962 and 1979, which have significantly compromised its structure. Earthquake- resistant rehabilitation studies to preserve the temple, declared a National Monument in 1984, were promoted at the end of the 1990s. They were the diagnosis of the structural conditions of seismic vulnerability and how it could be provided a greater capacity of response in terms of stiffness, resistance and dissipation of energy, as well as the diagnosis of the state and pathology of the materials. This included geotechnical studies of seismic amplification, dynamic behavior using environmental vibrations, 3D virtual modeling, and structural analysis, even with finite elements. For the reinforcement, the intervention of the base of the central spire was proposed, the control of the stability of the four corner spires, the construction of new structural walls joined in strategic points; founded in caissons and connected to each other in the upper level to guarantee the action of the diaphragm and a better seismic behavior of the structure. The interventions to improve the seismic resistance of the cathedral were carried out between 2002 and 2004. The treatment and protection of the concrete and other necessary interventions of its sculptures and images were carried out between 2016 and 2017. The objective of this document is to describe how a new generation of local specialists have studied andproposed, for this temple of 113 meters high, its seismic reinforcement, the treatment of its materials and other necessary protection interventions, in accordance with the state of the art of earthquake engineering, design, and construction of RC structures and the protection of historical heritage.

A Preliminary Structural Survey of Heritage Timber Log Houses in Tonsberg, Norway

Scipedia content — Tue, 30 Nov 2021 12:50:12 +0100

The formulation of a multi-hazard loss model for a given structure is not only of interest for predicting the economic impact of future damage but it can also be of importance for risk mitigation. A methodology that can assess the vulnerability of the built environment is a significant component of a loss model. The multi-risk vulnerability of heritage buildings necessitates greater knowledge about the history of their construction, including aspects relating to preserving them as assets. Timber as an organic material is more susceptible to decay and the structural assessment of timber buildings is essential for their preservation. A preliminary survey as a basis for multi-risk vulnerability assessment of such buildings is essential. In this step of the process, the history of the building is investigated, as well as any intervention to it during its lifetime. A damage inspection of structural elements conducted by experts is an essential part of the second step. After this, the configuration of the building, including height, plan view and connection details should be documented. After the preliminary survey of the building, detailed methods are employed to gather further information about the structure’s behaviour under different risk scenarios. In this paper, heritage timber buildings in Tønsberg, Norway have been selected as case studies for multi-risk vulnerability assessments. The preliminary survey has been conducted by a team of experts and useful data have been recorded and explained. 3D laser scanners have been used in the survey in place of traditional 2D methods to obtain a more detailed and accurate 3D representation of the buildings.

A Novel Non-Linear Discrete Homogenization Approach for the Analysis of Double Curvature Masonry Structures

Scipedia content — Tue, 30 Nov 2021 12:50:02 +0100

In the context of historical heritage, curved masonry structures as arches, vaults and domes represent the most distinctive and charming feature. Since the 17th century, several approaches have been developed in order to analyze their behavior, achieving nowadays techniques enable to combine ancient and modern methods. However, as these elements act as weak points of the structures during seismic events, the necessity of evaluating their vulnerability and safety level pushed the research to implement new numerical approaches. Although, the behavior of such structures is still not deeply investigated in literature as the high number of variables and uncertainty involved. An innovative discrete homogenized model approach is here proposed. The method provides the main features needed for proper simulation of masonry curved structures, including the orthotropy and the typical in-and-out-of-plane coupled behavior exhibited by masonry vaults. Moreover, homogenization procedures directly implemented in the method allows reducing by far the number of variables, leading to non-linear analyses without unpractical computational time. The model is conceived as an assembly of elastic units joint by non-linear interfaces. These latter are modeled as bricks elements and Concrete Damage Plasticity is used for modeling non-linear mechanical properties, coming from homogenization procedures. The discrete mesh is obtained automatically by means of an ad-hoc script. With the aim to validate the proposed approach, some non-linear simulations are carried out on examples of an unreinforced dome, of which experimental and numerical data are available, showing the reliability of the method and the accuracy of reproducing the evolution of the damage with a limited computational burden.

A New Method for Assessing Compatibility of Consolidation Procedures with Conservation Principles: Intervention Quality Index (IQI)

Scipedia content — Tue, 30 Nov 2021 12:49:54 +0100

In current times, built heritage is being lost at an alarming rate due to natural and human hazards. Policies for its protection and rehabilitation involve, among other things, challenges related to the refinement of suitable structural strengthening approaches. The arduous balance between gaining acceptable safety levels for occupants without deploying intrusive devices, inconsistent with conservation principles such as those of the ICOMOS charters, is not a simple task. The interest and efforts of the scientific community in this regard have been increasing for decades, but still, it is the structural professional 's responsibility and experience which must define this arduous balance on a case-to-case basis. This study addresses the question: How can the quality of structural rehabilitation interventions be assessed in light of conservation principles such as those given by ICOMOS? Here, a preliminary method - called “Intervention Quality Index” (IQI) method is proposed. It assesses the restoration intervention quality in relation to: (i) the level of compliance given by the conservation ́s principle score (conservation ́s factor, CF); and (ii) the current state of conservation of the monument (safety factor of building considering the seismic intensity, Δs). The IQI method considers the compliance level of the designed reinforcement with conservation principle, formalized through the fulfillment of a category, i.e. respected, partially respected, and not respected. Then, these judgments are translated into scores and statistically evaluated. Scores are attributed in relation to the relevance of the fulfillment of a certain conservation principle (authenticity, minimal intervention and intrusiveness, compatibility, recognizability and reversibility) for the seismic structural safety point of view. Preliminary results show that an effective employment of traditional earthquake-resistant practices together with a wise use of modern retrofit strategies allow for the preservation and reinforcement of built heritage without harming its identity.

A Method for the Structural Analysis and Design of Arched Reinforced Masonry and/or Concrete Structures

Scipedia content — Tue, 30 Nov 2021 12:49:47 +0100

Extraordinary architectural examples of shell structures have been built using reinforced masonry and concrete. The current sparse use of this construction type can be attributed, among other reasons, to a lack of simple design methods, tools and criteria. Extended Limit Analysis of Reinforced Masonry (ELARM) is a new method for the structural analysis and design of reinforced concrete, reinforced masonry or reinforced composite (masonry and concrete) arched structures. It is implemented computationally to create a flexible design and analysis tool, able to provide immediate graphical and intuitive results. The method is based on limit analysis but takes into account the material’s limited compressive strength and the vault’s cross-sectional bending capacity provided by the reinforcement as an equivalent increase of the thickness. The plastic theorems are then applied considering the new virtual boundaries of the vault’s intrados and extrados. ELARM is validated through the comparison of its predictions with the results of load tests on two full-scale composite barrel vaults. The vaults feature a structural system composed of a two-layered tile vault as an integrated formwork for a reinforced concrete layer. They were tested under vertical loading up to failure. Both the vertical and horizontal displacements of the vaults were monitored during the tests. The characterisation of the materials composing the vaults was also carried out to introduce the measured material properties and strengths in the equilibrium equations for the computation of the new virtual thickness. This paper presents the new structural analysis and design method, its experimental validation and some practical design examples to show the potential of the tool. It offers an intuitive process of design in which shape can be adapted and optimised, also having the material properties and thickness, loads and reinforcement quantity and placement as variable parameters. The presented examples include reinforcement optimisation and form-finding procedures and the analysis of a non-compression-dominated structure.

A Macroscale Modelling Approach for Nonlinear Analysis of Masonry Arch Bridges

Scipedia content — Tue, 30 Nov 2021 12:49:39 +0100

Masonry arches represent the most important structural components of masonry arch bridges. Their response is strongly affected by material nonlinearity which is associated with the masonry texture. For this reason, the use of mesoscale models, where units and mortar joints are individually represented, enables accurate response predictions under different loading conditions. However, these detailed models can be very computationally demanding and unsuitable for practical assessments of large structures. In this regard, the use of macro-models, based on simplified homogenised continuum representations for masonry, can be preferable as it leads to a drastic reduction of the computational burden. On the other hand, the latter modelling approach requires accurate calibration of the model parameters to correctly allow for masonry bond. In the present paper, a simplified macro-modelling strategy, particularly suitable for nonlinear analysis of multi-ring brick-masonry arches, is proposed and validated. A numerical calibration procedure, based on genetic algorithms, is used to evaluate the macro-model parameters from the results of meso-scale “virtual” tests. The proposed macroscale description and the calibration procedure are applied to simulate the nonlinear behaviour up to collapse of two multi-ring arches previously tested in laboratory and then to predict the response of masonry arches interacting with backfill material. The numerical results confirm the ability of the proposed modelling strategy for masonry arches to predict the actual nonlinear response and complex failure mechanisms, also induced by ring separation, with a reduced computational cost compared to detailed mesoscale models.

A Machine Learning Model for the Determination of Macro-Scale Masonry Properties based on a Virtual Laboratory at Micro-Scale

Scipedia content — Tue, 30 Nov 2021 12:49:30 +0100

Cutting-edge methods in the computational analysis of structures have been developed over the last decades. Such modern tools are helpful to assess the safety of existing buildings. Multi-scale techniques have been proposed to combine the accuracy of micro- modelling and the computational efficiency of macro-modelling. Machine-learning tools have been utilized successfully to train specific models by feeding big source data from different fields, e.g. autonomous driving, face recognition, etc. This research proposes a continuous nonlinear material law that can reproduce data from micro-scale analysis. The proposed method is based on a machine-learning tool that links the two scales of the analysis by training a macro-model smeared damage constitutive law through benchmark data from numerical tests derived from micro-models.

A Framework for the Detailed Flood Vulnerability Modelling of Built Cultural Heritage

Scipedia content — Tue, 30 Nov 2021 12:49:23 +0100

Flooding is the most common and damaging of natural hazards at global level, and in a context of climate change, flood risk is expected to increase. This has prompted governments and international agencies to adopt measures towards the reduction of flood risk in recent years. Among them is the development of flood risk assessments and flood risk management plans, with particular emphasis on cultural heritage, not only due to its significance for society, but also because of its particularly high vulnerability to natural hazards, including floods. In order to quantify risk and define prioritization and management plans for a given set of cultural heritage assets, vulnerability models that allow estimating and comparing the impacts of floods at an asset-by-asset level are required. However, there is currently a lack of approaches in the literature to achieve this. This study proposes a component-based synthetic modelling framework to perform detailed vulnerability analyses of cultural heritage assets. The framework is illustrated through an application to a Portuguese church.

A Constitutive Model for Rubble Masonry Allowing for Spread Micro-Cracks and Localized Macro-Cracks

Scipedia content — Tue, 30 Nov 2021 12:15:04 +0100

Starting from a discussion on the experimental results obtained from diagonal compression tests executed on in-situ masonry panels, the paper presents a constitutive model, together with a numerical formulation, to describe the cracking phenomena in rubble masonry structures. A classical finite element discretization is assumed with the hypothesis of a homogenous continuum material. The adopted constitutive model identifies three different phases: (i) the elastic phase; (ii) the micro-cracking phase, in which the formation of micro- cracks, spread in the structural members, is accounted assuming a plastic material with a strain hardening stable behavior; (iii) the macro-cracks phase, in which the formation of macro- cracks, developing along the edges of finite elements, are simulated by means of localized softening plastic deformation. While the numerical description of spread plasticity in the finite element framework is a topic that has been widely addressed in the past, the representation of localized plastic deformation and its implementation in a finite element code is an original contribution of the authors. From a computational point of view, the value of plastic deformations (i.e. crack openings) is found by solving a parametric linear complementarity problem (LCP) using mathematical programming algorithms. The main advantage of using an LCP method is its ability to deal also with configurations in which instability and a multiplicity of solutions are possible (e.g. softening behavior). The numerical simulation of a diagonal compression test and the comparison of the results with the experimental evidence are presented to validate the model

A Comparison Between Traditional and Modern Approaches for the Structural Modelling of Brick Masonry Barrel Vaults

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

Masonry vaults are widespread and characteristic structural elements of our built heritage since many centuries, but for a very long time they were built only based upon the experience and the proportional analysis of previous positive examples. Since the Hooke’s observations, in 17th century, about the shape of the catenary, and the first graphical analyses of 18th century, the tools for their “scientific” calculation have developed quickly [1], mainly to assess the stability of already existing structures rather than for the prevision of the future behaviour of new vaults. Despite the great progress in this field, ordinary programs for the static and seismic assessment of masonry buildings often disregard the vaults structural role and the professionals sometimes underestimate it, also due to the lack of attention dedicated to these structures by the technical codes. Therefore it seems now important to reconnect the elements of this modelling historical evolution, to compare the different methods and to find an equilibrium between complexity and reliability, making it accessible also to the common professional use, whose effects on preservation are important. To this aim, a pavilion vault was chosen as a reference, with given geometries and materials features, and the different methods were applied. On one side, traditional methods were chosen: the graphic Méry method [2] and the static theorem of limit analysis [3] have been applied to a system of 2D arches composing the vault. On the other side, a 2D Finite Element Model and the edge cutting ChronoEngine Distinct Element Model [4] have been also tested, under the same conditions. The influence of the brick pattern on the structural behaviour have been considered, conveniently defining the arches decomposition in the traditional methods and the blocks division in the Distinct Element Method. In all cases, calculations have been made changing both values and positions of the loads. The results are compared both in terms of stresses inside the masonry and in terms of deformation of the structural elements, evaluating the types of information and detail that the different approaches can supply. The results of the advanced numerical methods allow to assess the validity of the traditional approaches. On the other side, the possible contribution of the traditional methods to the calibration of the parameters for the numerical models is also discussed.

A Comparison Between Empirical Procedures for the Definition of Vulnerability Classes of Masonry Buildings: Application to Five Historical Centres Struck by 2016 Central Italy Earthquake

Scipedia content — Tue, 30 Nov 2021 12:04:33 +0100

The definition of seismic risk scenarios necessarily depends on the attribution of a vulnerability class to each building of a stock. In the macroseismic scale (EMS-98) the vulnerability class – from A to F – results from the combination between horizontal and vertical structures. On the basis of post-event surveys carried out in Italy after the earthquakes occurred in the last 50 years, many rules for converting the masonry quality and the stiffness of horizontal diaphragms into a vulnerability class have been proposed. However, despite the now high number of retrofitted or strengthened buildings in Italy, structural interventions are not mentioned in these procedures, except for metal tie rods and r.c. tie beams. The paper proposes a critical approach to the definition of vulnerability classes, by the means of applying the conversion rules to the same sample of 525 masonry buildings located in five historical centres struck by 2016 Central Italy earthquake: Acquasanta Terme, Campi Alto di Norcia, Castelsantangelo sul Nera, Muccia and Vezzano. They have been chosen due to the extensive strengthening campaigns that had been carried out after earlier seismic events. The preliminary recognition of the structural features of each building happens at the terms of the MUSE-DV Masonry, a rapid visual screening procedure recently proposed by the authors. The damage probability matrices (DPMs), obtained from each conversion, are compared to those from a theoretical model proposed for the EMS-98. Given the same poor masonry quality, the existing rules classify buildings in class A or B depending only on floors’ stiffness and horizontal connections. As a result, both low and high damage may appear in the same vulnerability class causing a bimodal trend in the damage distributions. Conversely, the MUSE-DV procedure allows to reduce these two frequency peaks by considering interventions. In fact, overall interventions, even on very poor masonry structures, may lead to a very low damage and, consequently, to low vulnerability classes (even C or D), while uncontrolled interventions could obtain a high damage and a high vulnerability. The twofold consequence is that a) structural interventions have a ‘relative’, i.e. positive or negative, contribution; b) the usual limitation to A and B vulnerability classes for random masonry buildings needs to be widened to better explain the damage observed in the 2016 Central Italy earthquake.

3D FE Modeling of Multi-Span Stone Masonry Arch Bridges for the Assessment of Load Carrying Capacity: the Case of Justinian’s Bridge

Scipedia content — Tue, 30 Nov 2021 11:49:39 +0100

Substantial part of heritage structures in Turkey is historic masonry arch bridges. To explore modeling issues, a numerical work has been initiated to better understand and preserve/transfer this heritage to the next eras. This paper specifically describes the influence of tensile fracture energy of stone material in determining their true load carrying capacities. A case study is presented to explain the modeling issues. With its historical background, current situation, geometric and material properties, this work focuses on numerical investigation of the historic multi-span stone masonry arch Justinian’s (or Sangarius) Bridge located in the city of Sakarya in Turkey over the Sakarya River. Numerical results show that the value of fracture energy in tension significantly affect the load carrying capacity and failure mechanism of multi-span masonry arch bridges. A more realistic nonlinear response has been obtained for an upper value of the tensile fracture energy of the stone masonry. The bridge model collapses by a-three-hinge mechanism occuring at the loaded arch in the upper value of the tensile fracture energy. The most critical loading point of the bridge is determined as the quarter-span.

“Iron Cages.” Technical Discussions after the 1906 Valparaíso Earthquake and Reconstruction with New Techniques and Materials

Scipedia content — Tue, 30 Nov 2021 10:54:30 +0100

A few months after the San Francisco earthquake and fire in April 1906, the prosperous and cosmopolitan city of Valparaíso (Chile) suffered a similar catastrophe, sparking the forerunner application of new materials and construction systems. After the earthquake, reports, and articles were produced analysing the characteristics of the earthquake and its effects on the built environment, emulating at a more basic level those emanating from the ad hoc commissions created to analyse the earthquakes in San Francisco and Messina (1908). At the theoretical level, solutions for reconstruction were discussed between reinforced concrete and steel structures, and the applications of these new materials, structural systems, and constructions in the world were closely observed. The solutions used for reconstruction ranged from proven inefficiencies prior to the earthquake to new techniques and materials. In this area, the use of steel with imported pre-manufactured systems as well as local solutions stands out. The need to reconstruct public and private buildings in Valparaiso with a reliable and fast system leaned the choice at the beginning towards the use of pre-manufactured metal structures. The article will expose and analyse the discussions of the time regarding construction systems and materials from a seismic-resistant point of view, complemented with the description of three emblematic cases of metal medium height construction in Valparaiso, after the earthquake: the Hucke Factory, Cardonal Market and the “Jabonería La Estrella” Factory.

The Lightweight Principle - An Important Key for Embodied Carbon Reduction in Construction

Scipedia content — Mon, 29 Nov 2021 17:24:39 +0100

Knitted Membranes: rethinking the design, fabrication and application of membrane architecture

Scipedia content — Mon, 29 Nov 2021 15:27:29 +0100

European ETFE-design – new findings and concepts

Scipedia content — Mon, 29 Nov 2021 15:05:15 +0100

Investigations on the structure of ETFE-films and their influence on the design, a survey with recommendations for the analysis

Scipedia content — Mon, 29 Nov 2021 14:45:46 +0100

Development and Analysis of Pre-Stressed Cable Roof with Stiffening Girder and Polymer Membrane Cladding

Scipedia content — Mon, 22 Nov 2021 13:41:32 +0100

Adjustment of Stresses in the Top Chord of the Dome-Like Hybrid Roof Structure

Scipedia content — Mon, 22 Nov 2021 13:40:55 +0100

Fabric formwork with ice in Canada

Scipedia content — Mon, 22 Nov 2021 13:38:17 +0100

Principal Symmetric Structures

Scipedia content — Mon, 22 Nov 2021 11:45:43 +0100

Transforming textiles to testimonies

Scipedia content — Mon, 22 Nov 2021 11:45:06 +0100

Appropriate design of structural membranes

Scipedia content — Mon, 22 Nov 2021 11:42:52 +0100

Design and Analysis of Baffled Inflatable Wing

Scipedia content — Mon, 22 Nov 2021 09:53:10 +0100

Structural membranes in motion

Scipedia content — Mon, 22 Nov 2021 09:51:40 +0100

Technical Design rules of ETFE membrane structures using the tensile strength measurements in production and development

Scipedia content — Mon, 22 Nov 2021 09:50:15 +0100

Advantages of spline-based interfaces for fluid-structure interaction in balloon-type problems

Scipedia content — Mon, 22 Nov 2021 09:41:27 +0100