Self-stressing Concrete Filled Steel Tube Calculation Of Ultimate Capacity Methods And Numerical Analysis

Self-stressing concrete filled steel tube can make full use of steel tube and concrete's fuction, which is a new steel concrete structure formed by the replacement instead of self-stressing expansive concrete with the ordinary concrete. Because of the presence of self-stressing, thin-walled outsourcing tube effectively restrain the expansion deformation of expansive concrete, and effectiveiy solve a mixed portfolio problem on steel bond interface caused by normal concrete shrinkage,as a result,they work together , make the internal structure of concrete more dense and improved compressive strength of concrete core. Steel tube take full advantage of the expansion properties of expansive concrete, have a greater chemical prestressing,and make higher lateral prestress for core concrete.At the same time,with the existance of self-stressing the steel tubes also produce initial stress which advance steel to yield,then that will affect the bearing capacity of concrete filled steel tubular structures.This paper study the contents of research on"capacity computational method and numerical analysis of self-stressing concrete filled steel tube structure",which is the Sub-topics of"experimental research on self-stressing concrete filled steel tube development and Application"(contract Number: 200631881422).Following are the studies:①Based on ordinary steel concrete constitutive, It comes up with core concrete constitutive included self-stressing effect;②On the basis of general theory of calculation of ultimate bearing capacity of concrete filled steel tube, apply the limit equilibrium theory and derive formula of ultimate bearing capacity of self-stressing concrete filled steel tube;③Discovered by analysising self-stressing concrete filled steel tube's performance under axial pressure,there is the best self-stressing lever, 0.11~0.12.Meanwhile ultimate bearing capacity of self-stressing concrete filled steel tube is at maximum which is 18% increase than that of ordinary concrete;④Apply and explain the impact mechanism of ultimate bearing capacity of concrete filled steel tube caused by self-stressing;⑤On the basis of applying basic assumptions and according to steel pipe concrete's struction features ,I numerically simulate the whole process of steel pipe concrete under axial pressure ,analysis sustainability mechanism of self-stressing concrete filled steel tube and the effect of of the core concrete's fracture from self-stressing,and fit formula of ultimate bearing capacity of self-stressing concrete filled steel tube.