Cyclic Out-of-Plane Testing of Clay Brick Masonry Walls Strengthened with Glass Fiber-Reinforced Polymer Strips.

The cyclic out-of-plane behavior of unreinforced masonry (URM) walls strengthened with externally bonded glass fiber-reinforced polymer (GFRP) strips is experimentally studied in this paper. A total of four fired clay brick masonry walls were prepared in this study. Three walls were seismically retrofitted by bonding vertical GFRP strips and one specimen was unreinforced and was used as built. All masonry walls were subjected to one-directional cyclic out-of-plane lateral loadings. The lateral cyclic out-of-plane behavior in terms of failure patterns, force-displacement behavior, ultimate strength and displacement capacity, secant stiffness, and hysteretic energy dissipation of each specimen was studied. The test results indicate that externally bonded vertical GFRP retrofitting significantly improves the cyclic out-of-plane performance of brick masonry walls. The ultimate out-of-plane flexural and displacement capacity of strengthened walls was increased up to 1000% and 300%, respectively, compared to the companion URM wall. Based on the principles of strain compatibility and internal force equilibrium, an analytical model is proposed for calculating the ultimate out-of-plane flexural capacity of GFRP-strengthened walls for different failure patterns. In addition, several design recommendations, such as the strain in GFRP strips at delamination failure and the maximum and minimum GFRP reinforcement ratio, were proposed based on strain compatibility. [ABSTRACT FROM AUTHOR]