Performance and bearing capacity calculation method of concrete-filled double steel tubular composite stub columns under fire
In order to study the fire resistance of concrete-filled double steel tubular composite stub columns(CFDST),a refined numerical model of CFDST was established.Based on the verification of test results of similar components,the high-temperature response law and fire resistance influence factor of CFDST were analyzed.The effects of internal pipe diameter thickness ratio,external pipe diameter thickness ratio,internal and external pipe diameter ratio were comprehensively analyzed.The fire resistance limits of CFDST with different section combinations(inner circle and outer circle,inner square and outer circle,inner circle and outer square)were compared and analyzed.Based on the theory of heat conduction analysis,the temperature field distribution formula of CFDST section was deduced,and the formula was modified according to the results of finite element simulation.Finally,based on the principle of temperature equivalence,the simplified calculation formula and bearing capacity calculation method of section temperature field of CFDST under fire were further proposed.The results show that CFDST has good fire resistance.Increasing the thickness of the inner steel tube when the diameter is unchanged and increasing the diameter of the inner steel tube when the thickness is unchanged are conducive to the improvement of the fire resistance limit.Under the condition of the same load and steel content,the fire resistance limit of CFDST with different section combinations is almost the same,but on the whole,the fire resistance of double circular steel tube concrete stub column is better.The difference between the simplified calculation formula of temperature field,the bearing capacity calculation method and the finite element results is less than 15％.
NETL
NSTL
万方数据
维普
