Seismic performance of exterior RC beam-column junction strengthened with Stainless Steel Wire Mesh (SSWM)

Abstract

Strengthening of concrete structures is necessary to enhance their performance in terms of serviceability and strength requirements as well as to increase the life span of the structure. In the past, different types of fiber-reinforced polymer (FRP) materials are widely employed for strengthening concrete structures. However, FRP-strengthened structural elements exhibit brittle failure as well as debonding of FRP strips or wraps. Due to debonding of FRP, its tensile strength is not fully utilized. To explore an alternative to FRP, Stainless Steel Wire Mesh (SSWM) is chosen in the present study. SSWM is a locally available material having lower tensile strength compared to FRP but having good bond characteristics with concrete and ductile behavior. The present study mainly focuses on experimental investigations to evaluate the behavior of beam-column junction strengthened using SSWM. In this experimental study, the performance of reinforced concrete beam-column junction is evaluated under cyclic loading. The reduced (one-third) scale test specimen representing an external beam-column junction of a 6-story regular moment resisting frame structure was tested under cyclic loading till its ultimate capacity. Subsequently, the damaged beam-column junction was strengthened using SSWM and its performance was again examined under cyclic loading. Minor cracks developed in the specimen were first filled with grout. Subsequently, epoxy-based adhesive SIKADUR 30 LP epoxy was used for bonding SSWM on the surface of the beam-column junction. The performance of test specimen was evaluated in terms of hysteretic response, displacement ductility, energy dissipation, degradation of stiffness, and failure modes of specimens. Results of experimental investigations show that SSWM effectively contributes to load resistance and enhances ultimate load carrying capacity and ductility of the beam-column junction without brittle or any significant debonding from concrete surface. Therefore, SSWM can be an economical alternative of FRP material for strengthening of concrete structures.