Study On Constitutive Relationship For Self-stressing Concrete Filled Steel Tube

Self-stressing concrete filled steel tube member (SCFST) is a new type concrete filled steel tube (CFST) structure. For SCRT members, the expansive concrete mixed are used to cast in the steel tube instead of the ordinary concrete. Comparing with the CFST, SCFST have some new characteristics. Microstructure of concrete core is more compact because the expansive behavior is confined by steel tube. Such expansion can result in good bond at concrete-steel interface, which can ensure the concrete and steel to work together. Because of high expansive energy, higher self-stress can generate in steel tube, which can offer confining pressure for concrete core. The SCFST members improve the mechanical performance of CFST structure. It is a self-development and self-perfection of CFST structure.Based on the Western Transportation Science and Technology Construction Project-Development Test and Applied Research on the Self-Stressing Concrete-Filled Steel Tube-design philosophy of Self-Stressing Concrete-Filled Steel Tube, following work has been carried out in this paper:â‘ Steel and concrete constitutive relation theory is contrasted and analyzed; suitable self-stressing concrete filled steel tubular structure material constitutive relation is found.â‘¡ANSYS software introduction includes linear analysis, non-analysis, and the flow control of APDL. Test course of SCFST columns is simulated through reasonable modeling, dividing mesh, and suitable loading method. The limited bearing capacity and the load-strain relationship curves of SCFST structures can be obtained. Using finite element analysis results, mechanical properties and mechanism of SCFST were analyzed, steel ratio, the strength of concrete and steel grade on the mechanics properties of SCFST was got.â‘¢Using the Enhancement-coefficient method and the Improve-coefficient method,simulated the SCFST mechanical behavior under axis-load,ansysed the two method and their scope application,confirmed the suitable constitutive. The tow constitutive relationships fitted the law of mechanical behavior of SCFST within the certain range.Finally,it putted forward the advice and prospect for further research on this work.