Masonry structures are types of structures that are generally built using materials such as stone, brick or concrete and are built by placing materials on top of each other. This type of building is a construction technique dating back thousands of years and was frequently used by ancient civilisations. Masonry structures continue to exist as a construction technique that maintains its importance with various advantages and disadvantages throughout history and today.
A large number of masonry structures date back to a period when building regulations did not exist and construction rules were of empirical origin. This often makes unreinforced masonry structures highly vulnerable to some load combinations. Since the construction of these structures was carried out without considering seismic effects, most of them are unable to absorb the seismic loads caused by earthquakes [1]. Especially in earthquake zones, the evaluation of earthquake performance of masonry structures has become an important issue in recent years [2]. Turkey is a seismic region with many fault lines including three major earthquake zones. The recent earthquake of 6 February 2023 affected 11 districts [3]. In order for this type of structure to survive, earthquake performance analyses of structures located in earthquake zones should be performed.
Masonry buildings display a highly nonlinear mechanical behavior, making it challenging to predict their typological characteristics numerically unless the appropriate material parameters and solution strategy are applied. In this subject, it is useful to compare the results of complex numerical analyses with simplified analyses in order to provide a practical perspective [4]. In line with this objective, various studies have been conducted in the literature. Yon et al. (2020) investigated conventionally built masonry structures damaged by earthquakes on the Eastern Anatolian Fault. As a result of the study in which the causes and mechanisms of collapse were analysed, solutions were proposed in accordance with the guidelines based on the conclusion that the biggest problem in the damage and/or collapse of masonry type structures is that they were not constructed in accordance with earthquake regulations [5]. Sayin et al. (2021) conducted an analysis of the Sivrice-Elazig earthquake, which had a moment magnitude of 6.8 and occurred along the Eastern Anatolian Fault zone. They explored the earthquake history and the current seismic characteristics of the region. The damages resulting from the earthquake were categorized into reinforced concrete, masonry houses, and non-residential structures, with the collected data subsequently discussed [6]. Sarhosis et al. (2021) studied school, residential and church type buildings in Greece. Damages caused by earthquakes with moment magnitudes of 6.3 and 6.1 were analysed in these structures. The findings show that the structures constructed in accordance with the latest seismic guidelines are less affected, while masonry structures built with traditional construction techniques are damaged [7]. Erdil et al. (2022) investigated the effects of earthquakes and environmental effects such as freeze-thaw on masonry structures in Van. 5.9 moment magnitude earthquakes, it was concluded that it was not damaged by environmental effects, but only damaged or collapsed due to the earthquake [8]. Uroš et al. (2023) considered a historical residential building located in Dubrovnik, a region with high earthquake risk. A numerical model of the structure was created in Abaqus finite element software and time history analyses were performed. Following the analyses, the critical sections of the structure were identified, and recommendations for strengthening were provided [9]. Valluzzi et al. (2022) analysed the damages to two thousand three hundred buildings in twenty villages after the earthquake in Italy in 2016. The impact of features such as geometric and architectural details, as well as horizontal and vertical structural components and their materials, was compared and assessed. As a result, they introduced new methodologies for the typological categorization and statistical analysis of construction parameters [10]. Gioffrè et al. (2022) investigated the dynamical response of two-story URM structures of the same geometry using shake table tests. The study concluded that enclosed masonry buildings perform better than unreinforced masonry buildings [11]. Misir et al. (2022) studied a historical masonry building and carried out material characterisation by non-destructive methods and mortar samples were taken. With the data obtained, large-scale wall specimens were prepared and quasi-static cyclic tests, ambient vibration tests were carried out and the stages of damage formation and the corresponding drift limits were obtained [12]. Oyguc (2022) analysed the structural damages caused by the Sivrice-Elazig earthquake that occurred due to the East Anatolian Fault. It was discovered that structures in rural areas suffered significant damage, revealing major shortcomings in both the design and construction phases of reinforced concrete and masonry structures in Elazig [13]. Vintzileou et al. (2022) took a masonry type structure and reduced it by ½ and constructed one as unreinforced masonry structure (URM) and the other as an addition with timber strips in the vertical direction. Both buildings were subjected to seismic tests up to the repairable damage level and the damages caused by these impacts were repaired. Both buildings were reinforced by grouting the wall and providing the diaphragm effect of the slab. After retrofitting, the structures were re-evaluated under seismic effects, leading to the conclusion that the applied retrofitting methods enhanced the earthquake performance of the structures. Additionally, it was found that timber ties can significantly improve the seismic resilience of historical masonry buildings [14]. Yon (2021) analysed another earthquake that occurred in Sivrice-Elazığ and investigated 65 masonry and adobe structures. As a result of this 5.2 moment magnitude earthquake, it was determined that structural damages were primarily due to deficiencies in the detailing of connections between walls or from walls to the roof, as well as the absence of beams. Strengthening methods have been proposed for undamaged structures in order to overcome these deficiencies [15]. Preciado et al. (2022) studied the impacts of 8.2 and 7.1 magnitude earthquakes on historic masonry structures in Mexico. They suggested practical methods for monitoring crack patterns in structural elements to ensure the effective strengthening of masonry buildings [16]. Duvnjak et al. (2023) focused on the recent earthquakes in Croatia, which have caused major damage to masonry structures, focussing on the interest in experimental research and structural performance assessment for reconstruction purposes. The assessment of structural conditions prior to the occurrence of seismic activities is of great importance to understand the influence on the stiffness of systems. This paper examines a damaged high school in Sisak, Croatia, through experiments like shear testing and operational modal analysis, alongside numerical modeling. The refined model, based on structural dynamics, assessed the building's pre-earthquake condition. The study highlights changes in natural frequencies and mode shapes between damaged and undamaged states, offering insights into post-earthquake dynamics [17]. Namlı and Aras (2024) analyzed and retrofitted an unreinforced masonry educational building under the Istanbul Project Coordination Unit, adding reinforced concrete layers with shotcrete to the walls. Six dynamic identification tests were conducted to monitor changes in the building's dynamic characteristics before and after retrofitting. The study shows that the retrofit effectively increased the structure's frequencies, though significant numerical differences between experimental and numerical results suggest careful consideration in seismic analysis of similar structures [18]. Kocaman and Kazaz (2023) assessed the seismic performance of four historically important masonry mosques. They performed nonlinear dynamic analyses using data from the 1992 Erzincan, 1992 Cape Mendocino, and 1995 Kobe earthquakes. The findings revealed that the mechanisms and crack patterns in domed mosques with square floor plans exhibited similarities [19]. Liguori et al. (2023) introduced a mechanistic framework for evaluating seismic vulnerability curves at a local scale, focusing on unreinforced masonry buildings in Cosenza, Italy. Using basic exposure data and an efficient finite element model, they performed static nonlinear analyses to assess structural behavior. Vulnerability curves were derived through Monte Carlo simulations, accounting for uncertainties. This method offers a framework for developing seismic vulnerability curves at the sub-municipal level [20]. Mohammad et al. examined the seismic response of masonry structures using nonlinear static analysis to develop vulnerability functions for various limit states. They evaluated the seismic performance of historic buildings in Karachi by modeling a prototype masonry structure with the 3-Muri tool and conducting pushover analyses for three material groups. The results were used to create damage matrices for different earthquake intensities, and empirical and analytical methods were compared to validate the findings [21]. Vitorino and colleagues (2024) used finite element modeling to assess the seismic response of the Cathedral of Santa Maria del Fiore in Florence. Seven natural acceleration records with recurrence periods of 50, 75, 101, 201, and 475 years were analyzed, and accelerations, tensions, and deformations were examined. As a result of the analyses, the failure zones of the structure were determined and evaluations were made [22]. Pacella et al. (2023) examined the difficulties encountered during the evaluation of the earthquake resistance of masonry structures by nonlinear finite element method and discussed how to evaluate the data obtained as a result of equivalent frame modelling method. In the case studies, linear and nonlinear analyses were performed and they emphasised that geometrical complexities in masonry structures require a special definition for each structure in the modelling phase. In line with these analyses, some solutions regarding modelling methods are proposed [23]. Uroš et al. (2024) analyzed an unreinforced historic masonry structure after the 2020 Zagreb earthquake to assess similar regional structures. They used response spectrum, static pushover, and out-of-plane collapse mechanism analyses, stressing the need to combine nonlinear static or dynamic analysis with out-of-plane analysis [24]. Romero-Sánchez et al. (2023) developed numerical models to assess earthquake impacts on complex historical structures, focusing on the Giralda Tower in Seville. Using OpenSees software, they conducted finite element and modal analyses, verifying damage assessments against previous earthquake records. The study emphasizes safeguarding historical buildings from seismic effects [25].
This study examines a single-story masonry building located in Istanbul, Turkey. The research includes linear earthquake performance analysis, nonlinear static pushover analysis, and kinematic analysis. The structural analyses of the residential building were conducted using the Turkish Earthquake Codes [26, 27]. The guidelines were applied collectively, and the analyses were repeated for three different earthquake levels. The linear performance analyses show the horizontal displacements of the structure and shear forces on the walls, while the nonlinear analyses provide a comparison with the linear results in terms of horizontal displacements. In the third stage, kinematic analyses were performed to examine the mechanisms that may occur locally in the walls of the structure. Based on the earthquake analyses and in-situ investigation findings, the structure's performance was evaluated under the impact of three different earthquake levels.