MECHANICAL ANALYSIS OF RECYCLED CONCRETE FILLED IN SQUARE STEEL TUBE AFTER HIGH-TEMPERATURE UNDER AXIAL COMPRESSION

In order to study the mechanical properties to axial compression performance of recycled concrete short columns filled in a steel tube after high temperature under axial compressive forces, the theoretical analysis has carried by using the finite element software ABAQUS, and experimental verification has also performed. The contrast analysis has experienced different temperature and different substitution rates of the whole process of a load-strain curve, revealing the main influence factors about the axial bearing capacity reduction coefficient after high temperature. The results showed that: with the experienced temperature rise and substitution rate increase, the short column's bearing capacity of recycled concrete filled in steel tube will have an overall downward trend, and it will have a bigger influence on bearing capacity when temperature above 500℃, while the replacement rate has less effect on the bearing capacity; with the experienced temperature rise, the influence magnitude becomes smaller, and the steel ratio, steel strength, compressive strength of core concrete have a significant influence on the axial compressive strength coefficient after high temperature , while substitution rate has no effect.