Dynamic Response of Masonry Walls Strengthened with Engineered Cementitious Composites under Simulated Debris Flow

Abstract

Unreinforced masonry buildings are prone to catastrophic damage when subjected to debris-flow impact. Engineered cementitious composite (ECC) layers were utilized to strengthen unreinforced masonry walls belonging to a 1/2 scaled timber-masonry building to mitigate the risk of collapse, and rolling steel balls of various masses were used to impact the strengthened walls to investigate the effects of the ECC layer strengthening. The typical characteristics of ECC, i.e., multiple cracking and high damage tolerance, were clearly exhibited during impacting, which helped to transfer the failure mode of the masonry walls from brittle to a much more ductile one. This article introduces strain response, displacement response, acceleration response, and dynamic property of the strengthened walls under impact. The test results demonstrated that ECC layer strengthening can significantly enhance impact resistance, including stiffness, energy dissipation, etc. For simplified assessment, the residual displacement ratio is recommended as the indicator to characterize the damage level of masonry walls strengthened with the ECC layers.