RC Frame Connections Rehabilitated by Jacketing

Abstract

The behavior of frame connections repaired and/or strengthened by jacketing was assessed experimentally. Four slab‐beam‐column joints were constructed and rehabilitated. The specimens were tested under bidirectional cyclic loading that simulated earthquake‐type motions. Variables were the jacketed element, level of damage of the existing structure prior to rehabilitation, and layout of jacketed column reinforcement. Test results indicated that jacketing was effective to rehabilitate the existing structure. The strength, stiffness, and energy dissipation characteristics of the existing structure were improved considerably by the jackets. The strength corresponding to joint failure, based on current recommendations for design of beam‐column joints, was exceeded by all the specimens. In this test series, no detrimental effect was found in the use of bundles in the jacketed column reinforcement. However, it is preferable to use distributed bars around the column perimeter to avoid bond failure. Finally, the construction of column jackets was done quite easily; however, beam jacketing required large and heavy forms as well as artful detailing during construction, features that might be uneconomical for U.S. practice.