The action of heated RC joints strengthened with a novel strategy combined CFRP and SSEMSM under a quasi-static cyclic load

The current work presents the application of a novel strategy for strengthening heated beam column (B -C) joints under a quasi-static cyclic load. This technique involves utilizing a layer of carbon fiber-reinforced polymers (CFRP) sheets with a layer of stainless-steel expanded metal sheet mesh (SSEMSM). These two layers are installed on the steel reinforcement cage inside the joint before concrete casting. Then the reinforced concrete B -C joints, after being cast and cured, were subjected to heat (i.e., 400 degrees C and 600 degrees C). The joints were divided into three groups: three joints were kept as is (i.e., reference joints; no strengthening was applied), whereas three joints were strengthened with the previously mentioned strategy. With a view to investigating the seismic behavior of RC joints, a quasi-static cyclic load was applied to the joints to simulate a seismic load. Results showed that the average maximum load capacity for upgraded joints (strengthened) increased by 30%, 19%, and 1% at ambient (i.e., 23 degrees C), 400 degrees C, and 600 degrees C temperatures, respectively, with respect to the reference joint (JCTA). More importantly, the experimental results reveal a significant increase in the cyclic response of strengthened joints (i. e., higher load capacity, greater displacement, higher dissipated energy, higher ductility, and slower degradation in the secant stiffness).