TEMPERATURE FIELD ANALYSIS OF SEMI-RIGID JOINTS FOR CFST COMPOSITE FRAMES

摘要

The bearing capacity and stiffness of concrete-filled steel tubular (CFST) structures after long-time high temperature or emergency fire accident were decreased or even serious collapse.To obtain fire resistance of semi-rigid joints for CFST composite frames, temperature filed distribution of composite joints in fire was studied.Thermal properties and boundary conditions of steel and concrete were determined.The temperature filed model of semi-rigid joints to CFST columns with slabs was made by using ABAQUS finite element software, in considering temperature rise stage of fire modeling.The effect of composite slab, fire type and construction location were discussed and the model was verified by the test results.The temperature distribution of composite joint under three or four-side fire condition was studied by the sequentially coupled thermal analysis method.The temperature versus time curves and temperature distribution of various construction and location were analyzed.The research results will become the scientific foundation of mechanical behavior and design method of semi-rigid CFST composite frames in fire.