The Finite Element Analysis On The Behaviors For Concrete-filled Rectangular Steel Tube Truss

Owing to many advantages such as large integral rigidity, high bearing capacity of joints and carrying large lateral loads, concrete-filled rectangular steel tube (CFRST) truss, a new-style structure, is one of the key structures for developing concrete-filled steel tube (CFST) application in the engineering. The nonlinear finite element analysis method and comparative analysis of test results with those of the numerical results are used to analyze the behaviors for truss structure in the paper, which can provide the basis for the design of engineering.The major contents are summarized as follows:1. Refer to the domestic and foreign research results, a generalization and summary to design rules, construction requirements and calculation of bearing capacity for CFRST truss is made. Some existing design problems on CFSRT truss are analyzed and the corresponding suggestions for designs are given.2. The basic theory of nonlinear finite elements analysis method is introduced, including element selection, material constitutive relation, failure criteria and the determination of their Parameters, meanwhile, consideration on bond relationship between steel tube and core concrete.3. The finite element models of RST truss and CFRST truss are separately established. Structure integral tension performance, deformation features, failure load, distribution of stress and failure modes under static loads are analyzed and discussed by comparing the numerical results with test results, which demonstrates the accuracy and validity of FEM models.4. The mechanical behaviors, load-transferring mechanism, stress and strain distributions of joints and members are comparatively researched, which judged the weakness of structure. Bearing capacity changes of joints and members with filled concrete and holistic resistant behavior changes are studied.5. The analysis results in this paper provide theoretical and experimental reference for the engineering application. In the end, proposals for further research on CFRST truss are also put forward.