عنوان مقاله [English]
The infills are walls which are in full contact with surrounding frame elements. They considerably increase the stiffness and strength. It is recommended in many rehabilitation codes and guidelines to model each infill by an equivalent compression-only strut element. However, before modeling infills in the structures, adequacy of the surrounding elements and connections should be checked for the infill forces. The same procedure is proposed for perforated infill panels, the infill with large opening such as door or window. Therefore, in rehabilitation projects, the capacity of infills, both solid and perforated, can be applied against seismic loads. However, a modification factor, shown by m in many codes or guidelines such as ASCE-41 or FEMA-356, is required. The m-factors of solid infill panels have already been calculated through experimental test results and listed in the guidelines. Despite, m-factors of perforated infills have not been determined yet.
The main subject of this paper is to calculate m-factors of perforated infill panels, based on the experimental test results of the literature and comparing them with those of similar solid infills. It is shown that m-factor of a perforated infill can be assumed almost the same value of similar solid infill panel. Regarding the importance of solid infills’ m-factors, they are focused. For this, many experimental test results of solid infills are reported herein and their m-factors are calculated. It has been shown that this factor depends only on infill material and, despite FEMA-356 or ASCE-41 suggestions; it is independent of infill aspect ratio or the ratio of the frame to the infill strengths. Eventually, m-factors of some infills with different materials are suggested; the m-factors of infills with clay bricks, clay hollow bricks and hollow tiles are 2, 3.5 and 3, respectively. For infills made of concrete blocks, the m-factor is 3 for hollow blocks and 4 for solid blocks.