Numerical investigation of concrete-filled multi-planar CHS Inverse-Triangular tubular truss

This paper describes a numerical investigation of concrete-filled multi-planar circular hollow section (CHS) Inverse-Triangular tubular truss using finite element analysis. The configuration of specimens is Pratt truss with symmetric geometry, loading application and boundary conditions by filling the concrete in the top chord members only. The material and geometric nonlinearities of concrete-filled tubular truss were carefully incorporated in the finite element models. The failure modes, load carrying capacities and overall deflections of all specimens were obtained from the numerical analysis. The nonlinear finite element models were calibrated against the corresponding test results for validation. Good agreement between the experimental and finite element analysis results was achieved. Therefore, an extensive parametric study of 256 specimens was carried out using the verified finite element models to evaluate the effects of main influential factors including cross-section dimensions of CHS tubes, concrete strengths filled in the top chord members and the critical non-dimensional geometric parameters on the strength and behaviour of concrete-filled multi-planar CHS Inverse-Triangular tubular truss. The optimum geometric parameters including the truss span to height ratio (L/H), the truss span to joint spacing ratio (L/S) and the truss height to width ratio (H/W) were proposed in this study for the economic design of concrete-filled multi-planar CHS Inverse-Triangular tubular truss.