Despite not being taken into account in structural modeling, the complex behavior of masonry affects the seismic performance of structures. The main aim of this study is to evaluate the effects of infilled frames with different percentages of openings on reinforced concrete (RC) moment frames. Initially, an experimental model was constructed and subjected to loading. Afterwards, corresponding numerical analyses were carried out based on the experimental model. A simplified micromodeling method with respect to the numerical simulation of the experimental model was assigned. Subsequently, sensitivity analyses were performed to investigate the effects of the opening ratio on the behavior of intermediate RC moment frames. The analytical results indicate that increasing the percentage of the opening leads to a significant reduction in the lateral strength of the frame. The lateral strength of the masonry wall was negligible in masonry infills with openings greater than 40 %. While prognosticating the behavior of buildings with masonry walls is complicated, determining the behavior of infilled frames with different percentages of openings will make it much easier to predict the damage pattern.

Many unreinforced masonry structures were vulnerable in the past earthquakes and required retrofitting. However, the vulnerability of masonry structures could solve by providing numerous retrofitting approaches, scarcity of appropriate methods that may provide a solution for the historical masonry structures with lesser effects on their façade is vehemently sensible. In this study, two one-third scale masonry wall specimens made by clay bricks were tested under constant vertical and cyclic lateral loading. The specimens consist of an unreinforced wall and a wall retrofitted by GFRP strips. This study investigates the seismic behavior of unreinforced masonry walls before and after using GFRP strips on their bedjoints. To this purpose, various patterns of using GFRP strips have been studied by simplified micro-modeling. The consequence indicates that the proposed retrofitting technique could improve the lateral strength and stiffness of the unreinforced masonry wall along with a considerable increase in the energy dissipation and ductility content, which leads to making a change in the behavior of the wall from brittle to ductile failure. The proposed method could apply to the modern historical structures in which cement mortar has been used as an adhesive between the masonry layers.

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