Diagonal Strut Mechanism of URM Wall Infilled RC Frame for Multi Bays

This study focuses on the in-plane behavior of unreinforced masonry infill walls installed in reinforced concrete frames. Two 1/4-scale model frames were designed, and the experimental parameter was the number of spans (single or double). Static cyclic loading tests were conducted to investigate the lateral force resistance mechanisms in the in-plane direction, which were evaluated based on the strain data measured on blocks forming the infill walls. The results indicated that the two-bay specimen formed a diagonal compressive strut in each infill wall similar to that formed in the one-bay specimen. To verify the strut mechanism, the compressive struts in the specimens were quantitatively identified based on strain data recorded on the infill. The identified compressive struts indicated that single strut models were applicable to multi-bay infilled frames.