Title: Evaluation of FRP and FRCM composites for the strengthening of reinforced masonry walls
Author(s): Zuhair A. Al-Jaberi, John J. Myers and Mohamed A. ElGawady
Publication: Symposium Paper
Appears on pages(s): 32.1-32.16
Keywords: Cyclic load; FRCM; FRP; masonry walls; out-of-plane; strengthening.
There are large numbers of existing buildings around the world and in North America especially in California have been constructed with reinforced masonry since 1930s. These old reinforced masonry walls have not been improved to meet the current standards. Current ACI 440.7R reported as Guide for Design & Construction of externally bonded FRP System for Strengthening Unreinforced Masonry Structures. This document does not address strengthening of existing reinforced masonry structures (i.e. with steel reinforcement). The principle objective of this study was to determine and discuss the failure mechanism as well as to investigate the flexural behavior of reinforced masonry walls strengthened with externally bonded system and subjected to out-of-plane cyclic loading. This will be evaluated by comparing the flexural capacity and ability to sustain large deflection of specimens strengthened with different strengthening systems. In addition, the effect of specific parameters on the flexural response of reinforced masonry wall was investigated including: type and amount of fiber and masonry bond pattern. This study aimed to develop a database of experimental test results to validate the design model presented in next version of ACI 440.7R document. The performance of twelve strengthened masonry specimens was investigated. The strengthening systems that used in this study are fiber reinforced cementitious matrix (FRCM) and fiber reinforced polymer (FRP) technique. These simply supported walls were tested in four-point bending with an effective span of 1.12 m (44-in.) between the supports under an out-of-plane cyclic load at a rate 1.27 mm/min (0.05-in./min). The test results indicated that the flexural behavior of reinforced masonry walls strengthened externally by FRP may be controlled by either FRP rupture or debonding (intermediate crack or plate end debonding failure). The flexural behavior of reinforced masonry walls strengthened externally by FRCM may be controlled by either fiber slippage or debonding.