Rehabilitation of Masonry Walls Using Unobtrusive FRP Techniques for Enhanced Out-of-Plane Seismic Resistance

TLDR

Unreinforced masonry walls are highly vulnerable to out‑of‑plane failure during earthquakes. The study aims to develop and evaluate cost‑effective FRP rehabilitation methods for strengthening historical and existing masonry walls. The authors fabricated ten full‑size clay‑brick walls and retrofitted them with unobtrusive FRP systems comprising flexible carbon fiber cables embedded in epoxy‑filled grooves at the bed and head joints. Testing revealed that the FRP retrofits significantly increased ultimate capacity, energy absorption, and deformability, demonstrating high efficiency under monotonic and quasistatic cyclic loading.

Abstract

Earthquake damage to unreinforced masonry buildings has shown the vulnerability of perimeter walls to out-of-plane failure. This paper describes a study that was carried out to develop and test innovative fiber reinforced polymer (FRP) rehabilitation techniques that meet the stringent requirements for strengthening historical buildings and to be cost-effective alternatives applicable to other existing masonry structures. Unobtrusive FRP rehabilitation techniques that utilize flexible carbon fiber composite cables, mounted near the surface of the façade walls in epoxy-filled grooves in the bed and head joints, were developed. Ten full size walls were constructed of clay bricks and retrofitted using the developed FRP rehabilitation techniques. The test results demonstrated the high efficiency of the rehabilitation techniques under both monotonic and quasistatic cyclic loadings. Significant increases in ultimate capacities, energy absorption, and deformability were achieved for various reinforcing schemes compared to the behavior of the unreinforced walls.