The Numerical Simulation On Mechanical Properties Of Steel Tube Reinforced Concrete Column Structure Under Sustained Loading And Explosion Shock Waves After Fire

Thanks to fire and explosion accidents occurred frequently in modern building structure, a lot of experts and scholars at home and abroad study of the structure fire resistance or antiknock performance, it covers the reinforced concrete column, the concrete filled steel tubular column and the steel reinforced concrete column, and other forms of structure. For this new type of the steel tube reinforced concrete column, the research mainly focused on the study of mechanical properties at room temperature conditions, for the mechanics performance under the joint action of fire and explosion was not reported. So the study of mechanics performance of SRC which is under the joint action of fire and explosion is very necessary.This research content is divided into the following several aspects:In the first instance, the constitutive relations and material parameters of concrete and steel in the process of analysis have been selected through summarizing existing research results at home and abroad. Contrast test model is established, and verify the validity of the finite element method, the numerical simulation results are in good agreement with the test results. The results show that the selected parameters and calculation method is reasonable, this topic using ABAQUS finite element software analysis has the very high accuracy.Secondary, the finite element analysis software ABAQUS is used here to simulate the process of SRC under sustained loading after fire when subjected to explosion effect, the simulation is divided into four processes: the initial load, the fire effect, the natural cooling and the explosion effect, including two models: the temperature field model and basic model. Examines the mechanics performance of SRC under the joint action of fire and explosion, including the stress and strain development of internals, the failure pattern of SRC as a whole, the relationship between initial load and explosion load, the relationship between ultimate bearing capacity and midspan deflection, and so on.Once more, according to the simulation results obtained that the final damage of SRC which is under the joint action of fire and explosion is caused by the steel tube to yield. Through transformate the different parameters of basic model, studying the effect of various parameters on the carrying capacity of SRC, sums up the main factors are the heating time, location factor and external strength grade of concrete.Eventually, reference existing specifications, according to the minimum level of civil air defense force of our country, determine the residual bearing capacity of the basic model in coaxial pressure and the influence of different parameters on the residual bearing capacity. Research has shown that change the steel ratio, and heat up time had a great effect on lateral remaining bearing capacity of composite column.