Improvement of ductile response of masonry infilled RC frame by using synthetic fiber

Disintegration of masonry panels endangers human life and causes significant economic losses during seismic events. Yet strengthening the masonry-infilled wall is the typical area of construction that receives the least attention. Previous studies found that small discrete fibers in concrete prevent cracking, improve ductility, and increase resistance to wear due to fatigue, shrinkage, or thermal stresses. However, there is no experimental study of using nylon fiber to improve the seismic performance of RC frames and masonry panels. In the present study, a laboratory investigation was conducted to observe the responses of four single-story, single-bay, and fully masonry-infilled RC frames, with or without nylon fiber (NF) in RC frame, cement mortar, and plaster, under cyclic loading to understand the impact of NF on the ductile response of walls. It was observed an increase in walls' maximum lateral load-bearing capacity by 4 %, 10 %, and 22 % for using NF in RC frame, mortar, and plaster, respectively, compared to the control specimen containing no fibers. Moreover, using NF in both the RC frame and infill components imparted the highest ductility, 21 % more cumulative energy dissipation, resistance to plaster wearing off, and delayed wall collapse after the diagonal tensile failure of the infill wall.