HGYF based ultimate bearing capacity analysis of rectangular CFST trusses

An efficient and high-precision linear elastic iterative method is proposed for ultimate bearing capacity analysis of rectangular concrete-filled steel tube (CFST) trusses, based on the homogeneous generalized yield function (HGYF). Firstly, a fiber model method is developed for evaluating the bearing capacity of rectangular CFST members under combined compression and bending. The influence of material strength and cross-sectional geometric parameters on HGYF of rectangular CFST members is investigated, and the main influencing factors are determined. Then, a HGYF for rectangular CFST members with wide applicability is formulated, based on which the element bearing ratio is defined and a linear elastic iterative method for ultimate bearing capacity analysis of rectangular CFST trusses is introduced on the basis of the elastic modulus reduction method. Finally, the results of the proposed method are compared with test data, generalized yield function (GYF) based results and the results from the traditional incremental nonlinear finite element method (INFEM). Results indicate that the presented HGYF can accurately predict the ultimate bearing capacity of rectangular CFST members while effectively addressing the limitations of GYF. Meanwhile, the proposed HGYF based method agrees well with the test results with high accuracy and efficiency, and can accurately identify the high and low bearing members of truss structure.