Quasi-static Test of Reinforced Concrete Frames After High Temperature

Abstract:

To investigate the seismic performance of reinforced concrete (RC) frames after high temperature, two strong-beam-weak-column frames and two strong-column-weak-beam frames were designed. Two of the frames were subjected to fire test, then low-frequency cyclic loading tests were conducted for all the specimens. The variation of failure modes, bearing capacities, load-displacement relationship, deformability, stiffness, and energy dissipation as the endured greatest temperature and the beam-column size relation was analyzed. The test results show that the bearing capacities and energy dissipation capacities of the RC frames were reduced after fire, and the reduction of those of the strong-beam-weak-column frames was more serious. The yield displacement increased and the ultimate displacement decreased. After fire, the plastic hinge first occurred at the bottom of the column, then the beam end, and then the top of the column, which indicates the plastic hinge tended to appear at the column ends. The RC frames designed according to strong-column-weak-beam criterion (in which plastic hinges first appear at the beam-ends) may fail in the form of strong-beam-weak-column after fire.

Key words:reinforced concrete frames; low-frequency cyclic loading test; seismic performance; after being exposed to high temperature; strong-beam-weak-column