Study On Load-carrying Capacity Of Concrete-Filled Square Tubular Column To Steel Beam Connection With Internal Diaphragms

As one of new composite structures in the field of Civil Engineering,concrete-filled rectangular steel tubular (CFRT) structure has high capacity, large energy absorption capacity, and high ductility, also it has regular shape which is easy to connect between columns and beams,convenient fire-control measure and short construction time.Therefore CFRT structure will become popular in medium-high rise residential construction.At present time, however, critical factors for which extensive applications of CFRT structure will be influenced is joint detail scheme.And there is no simple mathematical formulas for Load-carrying capacity of joint region.Thus investigation on joints between CFRT columns and steel beams in medium-high rise residential construction has significant theoretical and applied value.Based on the theoretical analysis, the mathematical formulas for determining joint shearing capacity and bending capacity were developed by using the principle of virtual work in this paper.Nonlinear FEM model involving geometric large deformation and materials nonlinear is presented.The Von.Mises failure criterion and multiplier kinematical hardening stress-strain relationships have been used for steel and the William-Warnke failure criterion and elastic plastic stress-strain relationships used for concrete.The 3D models of beam-to-column connections with internal diaphragms by 3D solid elements are founded.And the capacity behavior of connections under the monotonic loading are analyzed. The results of nonlinear FEM analyses can show the stresses distribution in the joints better, so that it provides the possibility to patch up the defects that couldn't observe in experiments in the details.And then,various factors of the influences of joints capacity behavior can be analyzed such as...