Theoretical Analysis And Experimental Study Of The Residual Bearing Capacity Of Concrete-filled Steel Tube Columns After Explosion

In this paper, the research on the residual bearing capacity of large size concrete-filled steel tube columns are carried out based on the explosion test of research group, 2 square and 2 circle concrete-filled steel tube columns are tested after the explosion,the main research includes the following aspects:1.The mechanical properties of concrete-filled steel tube columns are studied.Calculation formula of ultimate bearing capacity of circular and square concrete-filled steel tube columns under bending condition is obtained.The basic damage theory of concrete-filled steel tube is presented.The damage degree of the component is analyze based on the failure criterion of the vertical residual bearing capacity of the structure columns.2. The residual bearing capacity of concrete-filled steel tube columns are tested on 4 columns with different degree of damage,the curvature of the relation between the bearing capacity and the strain of the specimen is obtained,there is a obvious difference between the circle and the square concrete filled steel tubular column,circular specimens have obvious yield platform but the square ones have no platform;the relation curves between the bearing capacity and the displacement are obtained,change law is basically the same;the failure modes of the 4 specimens before and after the experiment are basically the same,the member failure occurs due to losing of overall stability.The results of the residual bearing capacity after the explosion test are compared with the theoretical calculation results before the experiment,the bearing capacity loss after the explosion of the concrete-filled steeltube columns are analyzed;the damage degree of 4 specimens is assessed,and the determination method of initial damage is given.3. The formula of residual bearing capacity of concrete-filled steel tube columns under blast loading are modified,the modified characteristic parameters are added,the4 test specimens are calculated by the modified formula,the calculated results are compared with the experimental results;the influence of three different factors(the yield strength of steel pipe, concrete strength grade and steel tube wall thickness) on residual bearing capacity is simulated by finite element,the simulation results are analyzed,the explosion resistance capacity of concrete-filled steel tube columns are better than the square one,the change of steel pipe wall thickness(change the the steel ratio of component) has a very significant influence on the improvement of the antiknock performance of component.