Structural Engineering and Computation, Cape Town, South Africa, 10 - 12 September 2007, pp.1993-1998
ABSTRACT: The beam-column joints that are not detailed and built in accordance with seismic codes present a serious hazard that can affect the overall ductility of a structure subjected to severe earthquake shocks. Due to the hazards associated with such deficiencies, many existing buildings have to be rehabilitated. Four half-scaled exterior beam-column joint specimens were prepared with only one of them conforming to the guidelines of ACI 318-02. The other three specimens were insufficient from view point of joint hoops and main reinforcements of beam and column. The performance and behavior of the reinforced concrete (RC) exterior beam-column joints rehabilitated using carbon-fiber-reinforced polymer (CFRP) fabric was experimentally studied under the
cyclic loads that simulate seismic excitation. The displacement controlled cyclic loads were applied to the beam tip, while column was subjected to constant axial load of 90 kN. In order to strengthen the deficient external beam-column joints, CFRP fabrics were laid out on the tension face of column and beam and then both column and beam were wrapped. Experimental results were compared against the sample designed in accordance to the ACI guidelines. The use of CRFP fabrics attached on the exterior surface of concrete was extremely effective on the ductility, absorbed total, dissipated and recovered energy in addition to ultimate displacement and load carrying capacity. Examination of the specimens after testing indicated that the strengthening method shifted the localization hinge of the specimen to the beam and the mode of failure of beam-column joints could be directly affected.
Keywords: Seismic rehabilitation, carbon fabric, beam-column joint, cyclic, energy absorption, ductility