Drift-based performance assessment has been a practical tool among the research and engineering community. However, several studies showed that there are several critical issues such as seismic damage definitions and their quantifications related to the displacement-based approach when it is applied not only to modern masonry structures but also to historical ones. The main reason is due to (i) failure mode dependency, (ii) geometry, loading and boundary conditions, (iii) inadequate prediction of the failure modes based on in-plane capacity formulations given in the codes. The present article discusses the reliability of drift limit values proposed by different codes and guidelines by comparing drift values derived in two datasets of masonry piers through considering an application to a real case study. It is observed that performance-based assessment is mainly based on the failure mode of the masonry structure, while the Guideline for Earthquake Risk Management of Historical Structures in Turkey, which is widely used in practice, proposes drift limits that are independent of the masonry behavior. Without consideration of the behavior mode can lead to incorrect assumptions and hence unconservative performance assessment outcomes for the architectural heritage.

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Masonry buildings of historical centres are usually organized within aggregates, whose structural performance against seismic actions is challenging to predict and constitutes still an open issue. The SERA—AIMS (Seismic Testing of Adjacent Interacting Masonry Structures) project was developed to provide additional experimental data by testing a half-scale, two-unit stone masonry aggregate subjected to two horizontal components of dynamic excitation. In this context, this paper investigates the reliability of the modelling approach and the assumptions adopted to generate a three-dimensional continuum finite element model. The work involves two stages, namely a blind pre-diction and a post-diction phase, and proposes a series of simulation analyses including a strategy to shorten the actual records and save computation costs. The study was performed to investigate the extent of uncertainty in modelling for such masonry aggregates in relation to the experimental outcomes. Pre-diction results were proven to be not accurate in terms of predicted displacements and damage patterns. The upgrades introduced for the post-diction analyses, including the calibration of the elastic modulus and the introduction of a non-linear interface between the two units, allowed to improve the outcomes, with reasonable results in terms of predicted base shear force, displacements along Y-direction and damage pattern for the non-linear stage. The overall approach showed to be appropriate for the structural analysis of existing masonry aggregates, but the accurate modelling of this type of structure remains challenging due to the high level of uncertainties.

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Masonry is one of the most used construction materials for structural and non-structural elements. The number of masonry constructions is still remarkable in countries where the costs of modern technology are high, as masonry solutions remain the most convenient and economical alternatives. Among these countries, unreinforced masonry is usually found in low- and mid-rise buildings, both residential and commercial. Developed countries, however, have favored alternative construction materials like reinforced concrete and steel, while masonry is regarded as an aesthetic and non-structural feature. Most objections to masonry construction are based on its lack of seismic performance. However, a substantial number of well- preserved masonry structures demonstrate that when they are built properly, they can withstand any form of loading, such as wind or seismic loads. Thus, masonry buildings’ seismic performance is underrated and experimental research is necessary to gain insight into their response. The studies available in the literature mainly focus on shake table testing of masonry buildings, while they have not been extensively studied in a quasistatic regimen. In this context, a half-scale two-story unreinforced masonry building with plan irregularity has been tested at the Laboratory of the Structures at the University of Minho. The experimental campaign involves cyclic quasi-static testing with a mode proportional unidirectional loading. Dynamic identification and digital image correlation techniques have been employed to monitor the damage progression. The test has resulted in a rocking response under lateral loading, with a wall detachment from the foundation and slab in the first and second levels, respectively. This paper presents and discusses the experimental procedure and the main outcomes of the study.@en

Performance-based design plays a significant role in the structural and earthquake engineering community to ensure both safety and economic feasibility. Its application to masonry building design/assessment is limited and requires straightforward rules considering the characteristics of masonry behavior. Nonlinear static procedures mainly cover regular frame system structures, and their application to both regular and irregular masonry buildings require further investigation. The present paper addresses two major issues: (i) the definition of irregularity in masonry buildings, and (ii) the applicability of classical nonlinear static procedures to irregular masonry buildings. It is observed that the irregularity definition is not comprehensive and has different descriptions among the seismic codes as well as among researchers, particularly in the case of masonry buildings. The lack of global language may result in the misuse of the procedures, while adjustments may be essential due to irregularity effects. Therefore, irregularity indices given by different codes and research studies are discussed. Furthermore, an overview of nonlinear static procedures implemented within the framework of the performance-based approach and improvements proposed for its application in masonry buildings is presented.@en

The present paper addresses the seismic performance of a half-scale two-story unreinforced masonry (URM) building with structural irregularity in plan and in elevation. The main objectives are (i) to understand the seismic response of URM buildings with torsional effects, and (ii) to evaluate the reliability of using simplified approaches for irregular masonry buildings. For this purpose, nonlinear static analyses are carried out by using three different modeling approaches, based on a continuum model, beam-based and spring-based macro-element models. The performance of each approach was compared based on capacity curves and global damage patterns. Reasonable agreement was found between numerical predictions and experimental observations. Validation of simplified approaches was generally provided with reference to regular structures but, based on the differences in the base shear capacity found here, it appears that structural irregularities are important to be taken into account for acquiring higher accuracy on simplified methods when torsion is present.@en

A seismic performance assessment of historical Kütahya Kurşunlu Mosque in Turkey is presented before and after it has been retrofitted. Site investigations were carried out to identify structural conditions, in which severe cracks, especially on the dome, were mapped. Regarding damage conditions, the Mosque has undergone several interventions, including retrofitting actions, in order to improve its seismic performance and global structural behavior. Effectiveness of seismic retrofitting of the Mosque was investigated by using the finite element method. Two representative structural models of the Mosque, namely non-retrofitted and retrofitted, were generated as a three-dimensional finite element model using an advanced structural analysis software. Ambient vibration measurements were performed to identify modal properties of the Mosque. Thus, the finite element model was calibrated and improved according to the experimental modal data. Nonlinear pushover and dynamic analyses were conducted to evaluate the seismic performance of the historical Mosque. This paper aims to demonstrate the effectiveness of the adopted retrofitting by comparing the models (before and after retrofitting) and, also, to validate the nonlinear behavior of the model by comparing it with the existing damage on the Mosque.@en