Rehabilitation of earthquake damaged external RC beam‐column joints by joint enlargement using prestressed steel angles

TLDR

The study investigates the effectiveness of joint enlargement using prestressed steel angles to improve the seismic behavior of damaged external reinforced concrete beam‑column joints. Three half‑scale joints with varying reinforcement were tested before and after rehabilitation, which involved epoxy grout injection and installing prestressed steel angles at the re‑entrant corners of the beam‑column joint. The rehabilitated specimens fully recovered seismic performance in strength, stiffness, and ductility, matching that of seismically detailed specimens. © 2016 John Wiley & Sons, Ltd.

Abstract

Summary The effectiveness of a rehabilitation method based on joint enlargement using prestressed steel angles to enhance the seismic behavior of damaged external reinforced concrete beam‐column joints was experimentally investigated. Three half‐scale joints having either non‐seismic or seismic reinforcement details were tested both before and after rehabilitation by applying lateral cyclic loading of increasing amplitudes. Two defects were considered for the two non‐seismic units, being the absence of transverse steel hoops and insufficient bond capacity of beam bottom steel reinforcing bars in the joint panel zone. The damaged specimens were rehabilitated by injecting epoxy grout into existing cracks and installing stiffened steel angles at the re‐entrant corners of the beam‐column joint, both above and below the beam, that were mounted and held in place using prestressed high‐tensile strength bars. The test results indicated that the seismic performance of the rehabilitated specimens in terms of strength, stiffness, and ductility was fully recovered and comparable with the performance of the seismically detailed specimen. Copyright © 2016 John Wiley & Sons, Ltd.