Fire Resistance of Concrete-Filled Square Hollow Section Columns in Two-Adjacent-Side Fire

摘要

Concrete filled steel tubular (CFST) columns have gained much attention for their excellent structural properties. This paper focuses on fire resistance of concrete-filled square hollow section (SHS) corner columns, which are usually under biaxial loading and two-adjacent-side fire loading. The thermal field of those members is asymmetric and additional eccentricity and additional deflection would be induced, which eventually changes the behaviour of those columns. A two-step sequentially coupled analytical approach was developed to predict the thermal and structural behavior of concrete-filled SHS columns, which was verified by related experimental results and then utilized for parametric studies. The parameters include load ratio, cross-sectional dimension, slendemess ratio, load eccentricity, steel and concrete strength, etc. It's found that the load ratio, cross-sectional dimension, slendemess ratio and load eccentricity are principal factors affecting fire resistance of concrete-filled SHS columns under two-adjacent-side fire loading. Based on the results of parametric studies, a design formula was proposed for predicting fire resistance of concrete-filled SHS columns in two-adjacent-side fire.