Experimental Investigation of Conventional Methods of Anchoring Masonry Infills to Steel Frames in Iran

Depending upon whether or not they are connected to the frame, infill walls display different performances and have varying effects on the structure and the force distribution between building frames. In most of buildings with steel or reinforced concrete frames, to partition the internal space and also to separate the inside of the building from outside, walls with masonry materials are used as infills. Masonry infill walls are composed of small, distinct elements which collectively act as a single unit. Videlicet, the masonry infill wall consists of discrete materials and since discrete materials generally exhibit a brittle behavior, they crack or fail during earthquakes which in most cases results in the loss of lives and capital. Thereupon, predicting solutions for bracing infill walls and preventing them from being destroyed in such a way that the structure can maintain its desirable performance seems necessary. The specifications of infills and the way they are connected to frames can exert considerable influences on the seismic behavior of the structure. In this study, to investigate the conventional methods of anchoring masonry infills to steel frames in Iran, the experimental results of four single-story, single-bay steel frames with the scale of 1:3 are presented, with a special focus on the different details of the connection between the infill wall and the surrounding frame. Three frames with masonry infills and one frame without an infill were constructed using conventional materials in Iran. All of the samples were tested by applying a lateral load on the upper beam. Different details regarding the connection of the infill to the frame including how the infill is connected to an un-anchored frame, connecting the infill to the frame using vertical separating angles, and the use of embedded rebars in the infill. The results showed that using the mentioned details to anchor the infill to the frame is not only quick and convenient, it also suitably delays the cracking of the infill panel, changes the failure modes of the wall, decreases the level of damage and maintains stability in the wall. The employment of these details also exerts a significant influence on the cracking patterns, failure modes, stiffness, strength, ductility, out-of-plane deformations, and energy dissipation.