Behavior of Concrete Members at Elevated Temperatures Considering Inelastic Deformation

摘要

A constitutive model of concrete subjected to elevated temperature is suggested in this study. The model is composed of four strain components: free thermal strain, mechanical strain, thermal creep strain, and transient strain due to moisture. The thermal creep strain of concrete is derived from the modified power-law relation for steady state creep. Mathematical description on the multi-axial creep behavior of concrete is also presented. The transient strain component is made in order to consider rapid irreversible strain change of moisture diffusion and evaporation. Some applications for the proposed model are carried out by a nonlinear analysis and compared with the test results. The comparisons with the test results show that the proposed model gives a good agreement and the influences of inelastic strain changes at elevated temperatures are very important for the structural response at elevated temperatures.