Performance assessment of unreinforced masonry arched walls under the action of lateral loading

In today's, the preservation and maintenance of masonry structures in historical areas have become very important. A significant part of this issue is rooted in the use of non-reinforced construction materials in the building of such structures. In Iran, most of the historical buildings were built using masonry materials. The buildings were designed according to the special architecture of this region. The existing structures mostly consist of masonry walls as well as some openings with arched configurations. In these types of walls, the wall consists of two piers and an arch on top of them. Since Iran is located in a highly seismic zone, investigating the performance of these types of structures is essential under the action of earthquakes and lateral loadings. Therefore, in this paper, a numerical investigation is accomplished on the in-plane behavior of traditional brick arches under the action of lateral loads. To this end, the numerical model of a sample of an existing arch (in Kerman’s Mesgari bazaar) was considered. The model was developed on STKO software. In this regard, the nonlinear response of bricks and mortar joints was simulated by using the DamageTC3D material. As well, the geometry of the wall was constructed with four-node plane-stress elements. The lateral capacity of the wall was assessed under the action of gravity loads. To this end, the wall was analyzed under gravity loads with intensities of 0.0 to 0.2 MPa. Next, it was pushed laterally through the pushover analysis and the shear force-displacement capacity curve of the wall was obtained. Through a specific procedure, the obtained capacity curves were estimated with a bilinear graph. By using this graph, the performance points corresponding to the wall’s capacity were extracted and a complete discussion was made regarding the shear capacity and the corresponding displacement to each performance point. Based on the obtained results from the analysis, it was observed that with an increase in the intensity of the applied gravity load, the maximum shear capacity of the walls increases. However, a higher increase in gravity load intensity (over a specific limit) would cause more damage to the arch which leads to a smaller shear capacity. Also, it is observed that the distribution of cracks and their pattern along the walls follow a similar outline. However, crack widths are affected strongly by the intensity of the applied gravity load on the wall.