Truss Model for Nonlinear Analysis of RC Members Subject to Cyclic Loading

The nonlinear finite-element analysis of RC members subjected to cyclic loading requires complicated modeling and analytical techniques. In the present study, a simplified nonlinear analytical method using a truss model was developed. In the nonlinear truss model, a RC member was idealized by longitudinal, transverse, and diagonal truss elements. Each element was modeled as a composite element of the concrete and the reinforcing bar. Cyclic stress–strain relationships were developed in order to describe the nonlinear behavior of the composite concrete and reinforcing-bar elements. The nonlinear truss model was applied to existing test specimens with various reinforcing-bar layouts under various loading conditions. The results predicted by the nonlinear truss model were compared with the test results. The comparison revealed that the nonlinear truss model predicted the load-carrying capacity and energy dissipation of the test specimens with reasonable precision. However, to estimate the deformation capacity of the specimens, the compression softening of concrete struts and the buckling and fracture of the reinforcing bar must be predicted more accurately.