Seismic performance of reinforced concrete frame joints after exposure to fire

An experimental study was carried out to investigate the seismic performance of fire-exposed reinforced concrete (RC) frame joints. This experimental program consisted of testing four full-scale joints used in RC frames. The first joint was tested under ambient conditions to serve as a benchmark case and to study room temperature response of concrete joints. The other three full-scale joints were exposed to different fire exposure scenarios and then tested, after cooling down to room temperature, by subjecting the joints to different levels of combined axial loading and cyclic lateral displacement history to simulate seismic loading conditions. Test results indicate that RC frame joints do not experience significant damage when exposed to 60 minutes of fire because most temperature-induced degradation in concrete and steel gets fully recovered upon cooling. However, joints in RC frames exposed to 90 minutes of fire undergo substantial damage due to significant temperature-induced property degradation in concrete and steel.