Numerical analysis of lateral displacement of beam-column joints in concrete frame structures subjected to fire

Abstract

In this article, numerical analysis has been conducted for multi-story reinforced concrete frames under different fire scenarios to investigate the time-dependent lateral displacement of beam-column joint, which is almost the same as the lateral displacement at column end. Based on the numerical results, an empirical model has been proposed to approximately determine the time-dependent lateral displacement of the beam-column joint, and the calculated results using this model are compared with the numerical and test results provided by other researchers. Finally, the fire performance of axially-and-rotationally restrained reinforced concrete columns with time-dependent sidesway is numerically analyzed and compared with that without sidesway. It is found that (1) when the target floor is on fire, the influence of its non-adjacent floors’ exposure to fire on the lateral displacement of the joints at the target floor can be neglected, and the biggest error induced by this neglect is less than 10%; but the exposure of its adjacent floor(s) to fire leads to larger lateral displacement of these joints; and (2) fire endurance of the restrained reinforced concrete column with high nominal axial load ratio (e.g. 0.6) decreases significantly with the increasing of the column’s sidesway.