Study on test and calculation method of axial compression bearing capacity of concrete filled steel tube considering ambient temperature
In order to study the influence of ambient temperature on the axial compression bearing capacity of concrete filled steel tube (CFST),the axial compression bearing capacity test of CFST short columns under different ambient temperatures was carried out to explore the influence of ambient temperature on the axial compression bearing capacity of CFST. Based on the limit equilibrium method,the theoretical calculation formula of axial compression bearing capacity of CFST considering the influence of ambient temperature was derived,and its accuracy was verified by experiments. The results show that the temper-ature change has significant influence on the bearing capacity of CFST columns. When the temperature decreases from 20 ℃ to-40 ℃,the bearing capacity of the specimen increases by 34.3% at most. The relative error between the calculated value of theoretical formula and the experimental value about the axial compression bearing capacity of CFST considering the influ-ence of ambient temperature is less than 10%,which has high accuracy. The research results can provide a theoretical basis for the design of steel tube confined concrete structures in alpine regions with large temperature difference.