EXPERIMENTAL RESEARCH ON POST-FIRE SEISMIC PERFORMANCE OF STEEL REINFORCED CONCRETE COLUMNS

An experiment on the temperature field and post-fire seismic performance of steel reinforced concrete (SRC) columns was carried out, in which eight large-scale specimens were used in order to reduce the size effect. First, the temperature distribution and evolution of the specimens during a fire is studied. Then, a systematic experimental study on the hysteresis curve properties, stiffness, and load carrying capacity of the SRC columns is carried out, considering such parameters as heating time, axial compression ratio, and steel ratio. It can be concluded that the temperature increase in the interior of the specimens is slower than that of the fire temperature, and the temperature increase in the inner core of the specimens is slower than that of the exterior. A plastic hinge zone appears when the SRC column specimen is loaded to collapse after fire, and the length of the plastic hinge zone increases with an increase in heating time. In general, the hysteresis curve is spindle shaped except for a small pinch effect, which means the energy dissipation ability of the SRC column specimens is still good after a fire. The load carrying capacity of the specimens decreases with an increase in the heating time, and the load carrying capacity increases with an increase in the axial compression ratio. The ductility decreases with an increase in the axial compression, and the studs have little influence on the load carrying capacity.