Traditional Masonry Buildings Research Articles

Fragility-based seismic assessment of traditional masonry buildings on Azores (Portugal) using simulated ground-motion records

Traditional unreinforced masonry structures are extremely vulnerable to seismic events, featuring large losses in many countries worldwide. This study focuses on the seismic assessment of a traditional masonry structures located in Faial Island—Azores (Portugal), which was hit by an earthquake of M w = 6.2 on 9 July 1998. A set of analyses was conducted through a probabilistic performance-based seismic approach, employing a stochastic finite-fault ground-motion simulation method to derive region-specific records and nonlinear numerical models to compute the capacity of the building. Subsequently, analytical fragility curves were derived considering different seismic scenarios. The results show a significant probability of the structural typology to reach moderate to extensive damage in the case of the specific earthquake, as observed in reality. The study holds significant importance in regions with limited recorded seismic activity, as they offer potential benefits for seismic risk management and mitigation strategies.

Structural response of half-scale pumice concrete masonry building: shake table/ambient vibration tests and FE analysis

Seismic performance evaluation of masonry structures is of paramount importance for ensuring the safety and resilience of buildings in earthquake-prone regions. There are limited number of studies on pumice elements in the literature. In addition, there are almost no studies investigating the earthquake behavior of pumice masonry building as a whole structure. In this context, a comprehensive understanding of their seismic response and dynamic characteristics has been lacking. To address this knowledge gap, a shake-table experimental campaign was undertaken, wherein half-scale pumice masonry building was exposed to simulated seismic forces. To enhance the experimental findings, numerical simulations were performed to confirm and expand our comprehension of how the pumice masonry structure responds to dynamic forces. Integrating both experimental and numerical outcomes provides a holistic understanding of how pumice masonry buildings behave during seismic events. At the end of the experimental study, the frequency values of the pumice model were observed to decrease up to 23.5% in the modes compared to the undamaged state. In the numerical model, this value decreases up to 19.85%. For the undamaged and damaged model, the first three experimental mode shapes were similar to the numerical mode shapes. Both experimental and numerical results show that the expected damages occur in the same regions. These results show that nonlinear FE models can be helpful in determining potential damage model locations. The findings have implications for the seismic design and retrofitting of similar traditional masonry buildings, facilitating the development of resilient and sustainable engineering solutions in seismic-prone regions.

Machine Learning (ML) Methods in Assessing the Intensity of Damage Caused by High-Energy Mining Tremors in Traditional Development of LGOM Mining Area

The paper presents a comparative analysis of Machine Learning (ML) research methods allowing to assess the risk of mining damage occurring in traditional masonry buildings located in the mining area of Legnica-Głogów Copper District (LGOM) as a result of intense mining tremors. The database of reports on damage that occurred after the tremors of 20 February 2002, 16 May 2004 and 21 May 2006 formed the basis for the analysis.
 Based on these data, classification models were created using the Probabilistic Neural Network (PNN) and the Support Vector Machine (SVM) method.
 The results of previous research studies allowed to include structural and geometric features of buildings,as well as protective measures against mining tremors in the model. The probabilistic notation of the model makes it possible to effectively assess the probability of damage in the analysis of large groups of building structures located in the area of paraseismic impacts. The results of the conducted analyses confirm the thesis that the proposed methodology may allow to estimate, with the appropriate probability, the financial outlays that the mining plant should secure for the repair of the expected damage to the traditional development of the LGOM mining area.

Post-earthquake damage assessment of traditional masonry buildings: A case study of Bhaktapur municipality following 2015 Gorkha (Nepal) earthquake

Bhaktapur municipality, one of the historic urban area, suffered heavy damage to many of its public residential buildings due to April 25, 2015, Gorkha (Nepal) earthquake. Immediately after this devastating earthquake, rapid visual damage assessment of 3979 buildings, in seventeen wards of Bhaktapur municipality, was carried out. This study was motivated to bring consciousness, revealing the vulnerable parameters of traditional masonry construction practice, for future safer buildings construction practice at this neighbourhood. Moreover, the establishment of 2105 Gorkha earthquake induced damage databases are undertaken, aiming to increase the availability of damage data for future research work.In this paper, the results obtained from comparative analysis of damage database and chi-square test for its validity is presented. Nevertheless, it is necessary to carry out detail damage assessment to identify the seismic sensitivity of the common structural components.

Discrete-element analysis of floor influence on seismic response of masonry structures

Traditional masonry buildings are highly vulnerable to earthquake loading and their dynamic response is strongly influenced by the in-plane deformability of the timber floors and the quality of the wall-to-floor connections. Understanding the behaviour of timber floors and roofs and their interaction with masonry walls is therefore fundamental for the protection of historical buildings. In a previous research project, different timber-based dry-connected strengthening solutions for timber floors were tested under in-plane loading. The experimental results showed a significant increase in shear strength and stiffness. In the current study, the discrete-element method (DEM) was used to model a simple masonry structure and evaluate the effectiveness of strengthening solutions to avoid triggering first-mode mechanisms, namely out-of-plane collapse of masonry walls. The structure was stressed by seismic ground accelerations. The unreinforced and reinforced floors were modelled with non-linear springs that reproduced their experimental hysteretic response. Parametric analyses were performed, changing the geometry of the structure and the masonry wall thickness. The comparison highlighted the effectiveness of the proposed wood-based strengthening solutions for reducing out-of-plane displacements of masonry walls, potentially matching the performance of rigid floors.

Structural evaluation of traditional masonry buildings during the February 6 - 12, 2017 Ayvacık (Çanakkale) earthquakes in Turkey

Structural evaluation of traditional masonry buildings during the February 6 - 12, 2017 Ayvacık (Çanakkale) earthquakes in Turkey

Vulnerability to Flash Floods: A Simplified Structural Model for Masonry Buildings

AbstractUrban and land use planning is conditioned by flood risk analyses and is a great research challenge. While methods are available for quantitative hazard and risk modeling, there is still a major gap related to reliable rational approaches for vulnerability assessment. This is particularly true for assessing vulnerability of buildings to floods. This vulnerability, which is important for economic reasons as well as for the safety of individuals and communities, is usually conceptualized on an empirical basis. Such empirical approaches, however, are plagued by considerable uncertainties, mostly because the damage‐causing mechanisms on the building envelope are poorly represented. In order to advance this area, this paper focuses on the structural vulnerability of traditional masonry buildings in alpine areas exposed to flash floods. A simplified physically based conceptual model which requires a limited amount of input data is proposed. The resistance of a wall impacted by a flash flood is studied in a limit analysis framework, considering different geometric ratios and building configurations. The resulting stability thresholds, expressed in dimensionless form as a function of the water depth, were positively compared with the results provided by numerical finite element models of the investigated geometries. The application of the proposed vulnerability model in risk mitigation strategies provides reliable information, suitable for a first‐level risk assessment on large building stocks.

Analysis of the impact of large scale seismic retrofitting strategies through the application of a vulnerability-based approach on traditional masonry buildings

The buildings’ capacity to maintain minimum structural safety levels during natural disasters, such as earthquakes, is recognisably one of the aspects that most influence urban resilience. Moreover, the public investment in risk mitigation strategies is fundamental, not only to promote social and urban and resilience, but also to limit consequent material, human and environmental losses. Despite the growing awareness of this issue, there is still a vast number of traditional masonry buildings spread throughout many European old city centres that lacks of adequate seismic resistance, requiring therefore urgent retrofitting interventions in order to both reduce their seismic vulnerability and to cope with the increased seismic requirements of recent code standards. Thus, this paper aims at contributing to mitigate the social and economic impacts of earthquake damage scenarios through the development of vulnerability-based comparative analysis of some of the most popular retrofitting techniques applied after the 1998 Azores earthquake. The influence of each technique individually and globally studied resorting to a seismic vulnerability index methodology integrated into a GIS tool and damage and loss scenarios are constructed and critically discussed. Finally, the economic balance resulting from the implementation of that techniques are also examined.

Seismic vulnerability assessment of the old city centre of Horta, Azores: calibration and application of a seismic vulnerability index method

The seismic vulnerability assessment of old masonry buildings is essential not only to buildings with recognised historical and heritage value but also to ordinary residential masonry buildings. Thus, and resorting a wide set of damage data collected after the 1998 Azores earthquake, this paper addresses the topic of the seismic vulnerability assessment of traditional masonry buildings through the calibration and application of a simplified vulnerability assessment method to the old city centre of Horta (Faial Island), in Portugal. In this case study, 192 buildings were assessed using this methodology, and vulnerability and loss scenarios were analysed using an integrated Geographical Information System tool. As is discussed in this paper, such procedure could allow city councils or regional authorities to plan interventions based on a global view of the site under analysis, leading to more accurate and comprehensive risk mitigation strategies, which can than support the requirements of safety and emergency planning.

Simple Seismic Assessment of Traditional Unreinforced Masonry Buildings

ABSTRACTA framework for quick seismic assessment and retrofit of traditional unreinforced masonry (URM) structures is presented. The proposed methods build on simple principles of structural dynamics and are used as an alternative to detailed time-history analysis, in recognition of the prevailing need for simple and practical methods, compatible with the low-budget and the limited level of knowledge regarding materials, internal force paths, connectivity and condition of older URM structures. An objective is to identify areas in the building that are particularly susceptible to damage and for guiding the types of the required global interventions to improve seismic response. Demand and supply are expressed in terms of relative drift ratios that quantify the intensity of out-of-plane differential translation and in-plane shear distortion of masonry walls. A characteristic traditional building type of timber-laced masonry is used as a model structure for illustration of concepts. The morphology and geometry of the building correspond to a statistical sample of the actual traditional unreinforced masonry buildings (TURM) found in historical centers of many towns in the greater region of Northern Greece. The methodology is particularly useful for setting retrofit priorities and management of the collective seismic risk of historical entities.

Simplified Mechanical Model to Estimate the Seismic Vulnerability of Heritage Unreinforced Masonry Buildings

Traditional or historic masonry structures occur in large populations throughout the world, particularly in preserved historical city clusters. Being non-engineered and aging these structures are in urgent need of assessment and seismic repair/rehabilitation. However, traditional masonry presents important challenges to computational modeling, owing to complexity of structural system, material inhomogeneity, and contact interactions that collectively can only be addressed through detailed 3D nonlinear representation. In this article, a simple performance assessment model is developed in order to address the need for preliminary assessment tools for this class of structures. The objective is to be able to rapidly identify buildings that are at higher risk in the event of a significant earthquake, potentially justifying a second round of more detailed evaluation. The proposed model defines the characteristics of a Single Degree of Freedom representation of the building, formulating consistent 3D shape functions to approximate its fundamental mode of vibration considering both in-plane and out-plane wall bending as a result of insufficient diaphragm action. Parametric expressions for the dynamic properties are derived in terms of the important geometric, material, and system characteristics, and are used to express local demand from global estimates. Acceptance criteria are established both in terms of deformation and strength indices to guide retrofit. An application example of the proposed assessment methodology is included to demonstrate the ability of the model to reproduce the essential features of traditional masonry buildings under seismic action.

Seismic Risk Assessment of Historical Eastern Turkish Buildings by Finite Element Analysis

Traditional masonry buildings, commonly built in Turkey, are one of the important items of cultural heritage. There are many important historical buildings in the east part of Turkey. One of the important locations in east of Turkey is Kilis. In this study, Kilis houses of original types in terms of architectural and functionality, were examined regarding the e ects of an earthquake. Therefore, ve traditional Kilis houses were examined and the buildings were modeled using SAP2000 nite element software. The models were investigated with di erent materials such as stone, brick, pumice and cellular concrete material. Time history analyses were performed for the modeled buildings, with three di erent ground motion records. Displacement values, compressive stresses, tensile stresses, shear stresses and base shear values, obtained from the analysis results were examined in detail. When the results of the study were evaluated, earthquake resistance of buildings was was found to be high and the displacements values were not at a signi cant level.

The 2012 Emilia (Northern Italy) earthquake sequence: an attempt of historical reading

In May–June 2012, the Po Valley (Northern Italy) was struck by an earthquake sequence whose strongest event occurred on 20 May (Mw 5.9). The intensity values (Imax 7–8 EMS98) assessed through macroseismic field surveys seemed inappropriate to describe the whole range of effects observed, especially those to monumental heritage, which suffered very heavy damage and destruction. The observed intensities in fact were significantly lower than those we could have expected after a Mw 5.9 event for Italy. As magnitude-intensity regressions are mainly based on historical earthquake data, we handle this issue going back in time and debating the following hypotheses: (a) the 2012 Emilia earthquake sequence shows lower intensity values than expected because the affected urban context is more heterogeneous and much less vulnerable than that in the past; (b) some historical earthquakes, especially those that occurred centuries ago and are provided with little information, could show a tendency to be overestimated in intensity, and consequently in magnitude. In order to give consistency to such hypotheses, we have introduced, as a test, a dual historical reading of the 2012 Emilia earthquake sequence as if it had occurred in the past: the first reading refers to a period prior to the introduction of concrete in buildings assessing the intensity on traditional masonry buildings only. A further historical reading, assessed by using information on monumental buildings only, was performed, and it can be roughly referred to the XVI–XVII centuries. In both cases, intensity values tend to grow significantly. The results could have a relevant impact when considered for seismic hazard assessments if confirmed on a large scale.

Numerical study on the performance of improved masonry-to-timber connections in traditional masonry buildings

This paper deals with a numerical study on the structural performance of masonry-to-timber connections in ancient buildings. The work is supported on an experimental campaign carried out at University of Minho, which aims at characterising a strengthening solution based on the use of injected anchors for the improvement of the connection between masonry and timber frame walls. The numerical study resorts to a detailed 3D finite element model, which reproduces the experimental test setup and procedure. The modelling approach adopted allows an accurate characterisation of the behaviour of all structural elements, in terms of stress field and displacement distribution. The 3D model was validated against the available experimental results, which was then used to perform parametric analyses in order to evaluate the influence of key parameters. Finally, simplified analytical approaches to estimate the strength capacity of injected anchors on masonry are presented and discussed.

Seismic vulnerability assessment of masonry facade walls: development, application and validation of a new scoring method

This paper approaches the issue of seismic vulnerability assessment strategies for facade walls of traditional masonry buildings through the development of a methodology and its subsequent application to over 600 building facades from the old building stock of the historic city centre of Coimbra. Using the post-earthquake damage assessment of masonry buildings in L\'Aquila, Italy, an analytical function was developed and calibrated to estimate the mean damage grade for masonry facade walls. Having defined the vulnerability function for facade walls, damage scenarios were calculated and subsequently used in the development of an emergency planning tool and in the elaboration of an access route proposal for the case study of the historic city centre of Coimbra. Finally, the methodology was pre-validated through the comparison of a set of results obtained from its application and also resourcing to a widely accepted mechanical method on the description of the out-of-plane behaviour of facade walls.

SOFIE project – 3D shaking table test on a seven‐storey full‐scale cross‐laminated timber building

SUMMARYMulti‐storey buildings made of cross‐laminated timber panels (X‐lam) are becoming a stronger and economically valid alternative in Europe compared with traditional masonry or concrete buildings. During the design process of these multi‐storey buildings, also their earthquake behaviour has to be addressed, especially in seismic‐prone areas such as Italy. However, limited knowledge on the seismic performance is available for this innovative massive timber product.On the basis of extensive testing series comprising monotonic and reversed cyclic tests on X‐lam panels, a pseudodynamic test on a one‐storey X‐lam specimen and 1D shaking table tests on a full‐scale three‐storey specimen, a full‐scale seven‐storey building was designed according to the European seismic standard Eurocode 8 and subjected to earthquake loading on a 3D shaking table. The building was designed with a preliminary action reduction factor of three that had been derived from the experimental results on the three‐storey building.The outcomes of this comprehensive research project called ‘SOFIE – Sistema Costruttivo Fiemme’ proved the suitability of multi‐storey X‐lam structures for earthquake‐prone regions. The buildings demonstrated self‐centring capabilities and high stiffness combined with sufficient ductility to avoid brittle failures. The tests provided useful information for the seismic design with force‐based methods as defined in Eurocode 8, that is, a preliminary experimentally based action reduction factor of three was confirmed. Valid, ductile joint assemblies were developed, and their importance for the energy dissipation in buildings with rigid X‐lam panels became evident. The seven‐storey building showed relatively high accelerations in the upper storeys, which could lead to secondary damage and which have to be addressed in future research. Copyright © 2013 John Wiley & Sons, Ltd.

Verification of Masonry Building Code to Flexural Behavior of Cement-Stabilized Soil Block

AbstractMost studies involving cement-stabilized soil blocks (CSSB) concern material properties, such as the characteristics of erosion and strength and how the composition of the block affects these properties. Moreover, research has been conducted on the performance of various mortars, investigating their material properties and the tensile bond strength between CSSB units and mortar. In contrast, very little is currently known about CSSB masonry structural behavior. Because structural design codes of traditional masonry buildings were well developed over the past century, many of the same principles may be applicable to CSSB masonry buildings. This paper details the topic of flexural behavior of CSSB masonry walls and whether the Masonry Standards Joint Committee (MSJC) code can be applied to this material for improved safety of such buildings.

Building waterproofing remediation applying the 'total cut' method

The paper analyzes the specific problems of construction of a waterproofing system with an absolute control of the vertical penetration of ground water and dampness from the ground into higher levels of building masonry structure. This method can very suitably be applied in rehabilitation of old brick buildings where the usual waterproofing remediation systems cannot be implemented because of specific structure system The 'total cut' method is very suitable for use in the old traditional masonry buildings, which do not have reinforced concrete vertical beams and where using this method would not interfere with the continuous stability of the building.

Evaluation of Strengthening Techniques of Traditional Masonry Buildings: Case Study of a Four-Building Aggregate

Increasing appraisal of the durability, conservation state, and changeable use and function of old buildings in urban centers relies a great deal on the structural safety evaluation of vertical load capacity and the ability to resist horizontal forces. The need to assess seismic vulnerability, particularly of traditional masonry buildings, is a key issue. Evaluation of the seismic vulnerability of old buildings is essential in the definition of strengthening needs and minimization of damage from seismic actions in the safeguarding of built heritage. A three-dimensional model was developed for an aggregate of four traditional masonry buildings located in the old city center of Coimbra, in Portugal. The finite element modeling of these buildings has aimed to identify structural fragility, understand the damages detected, and evaluate the global structural safety of these types of buildings. The primary results obtained in this case study helped to interpret the structural damage and stress distribution, and...

Determination of mechanical properties of traditional masonry walls in dwellings of Faial Island, Azores

AbstractThe determination of mechanical properties of masonry walls is a fundamental pre‐requisite for the characterization of the seismic response of traditional buildings, which helps on the definition of adequate rehabilitation and strengthening procedures.This paper presents a testing campaign carried out in the Cedros region of Faial Island, Azores, hit by the July 98 earthquake, aiming at the determination of physical and mechanical properties of stone masonry walls, namely the mass density and Young's modulus.The paper describes the developed testing techniques as a contribution to the study and the preservation of traditional masonry buildings. Copyright © 2002 John Wiley & Sons, Ltd.