In-Plane Shear Behavior of Unreinforced Masonry Walls Strengthened with Fiber Reinforced Polymer Composites

摘要

Unreinforced masonry (URM) wall is one of the oldest types of walls used around the world. During earthquakes, URM walls present a real danger to life safety due to their behavior characterized by a brittle failure caused by their feeble shear resistance to in-plane loads, which make their strengthening necessary. Numerous studies had been used fiber reinforced polymer (FRP) as strengthening systems to upgrade the seismic behavior of masonry walls. In this study, the effectiveness of using carbon fiber reinforced polymer (CFRP) to increase the energy dissipation and the load carrying capacity of URM walls subjected to in-plane loading is experimentally investigated. Tests were carried on five walls subjected to diagonal compression loadings, one wall was considered as a reference and the other were retrofitted by different configurations of unidirectional CFRP wraps. Despite the advantages associated with the use of such systems, it remains expensive to use, therefore in this study, different ratio and configurations of CFRP wraps were used to reinforce masonry walls to enhance their resistance with less costs. The parameters under investigation are the dimensions, the number and the orientation of CFRP layers. It was concluded that the CFRP enhance the shear resistance and the deformability of URM walls. Results show The CFRP wraps had a significant influence on the URM wall behavior. Important amelioration of deformations and ultimate shear strength were observed when the specimen reaches its peak load, it was determined that the use of CFRP wrap even in smaller ratios increased ductility, the load-bearing capacity and the in-plane shear strength capacity of the masonry walls. The compressive strength of the strengthened walls had experimentally observed to be 147.31% to 319.35% higher than URM wall. The CFRP wraps presents an important solution for the improvement of the in-plane behavior of masonry walls.