Flexural Behaviours of Reinforced Concrete Columns Confined by Circular Steel Tubes after Fire Exposure

Abstract

The post-fire flexural behaviours of steel tube confined reinforced concrete (STCRC) columns (also known as reinforced concrete columns confined by circular steel tubes), were investigated in this paper. A 3D finite element (FE) model was developed with the program ABAQUS, using the sequentially coupled thermal-stress analysis method. A set of test data was used to verify the FE model and good agreement was achieved. The moment versus curvature curves were analysed and discussed. After that, parametric studies were performed to investigate influences of some key parameters on the flexural capacity and flexural stiffness of STCRC columns, including heating time, cross-sectional dimension, material strength, steel tube to concrete area ratio and reinforcement ratio. Simplified design methods were proposed for predicting flexural capacity and flexural stiffness of STCRC columns after exposure to ISO-834 standard fire condition.