Mechanical Properties of Steel-Concrete Composite Section in Space Rigid Frame

In order to investigate the mechanical properties and load transfer mechanism of steel-concrete composite section in a space rigid frame structure for high-speed railway, a section model test with a scale of 1 to 2 and nonlinear finite element analysis were carried out. The test model was loaded respectively under a serviceability limit state and an ultimate limit state to obtain the distributions and variations of stresses and deformation of main members in loading process. In addition, the relationship of load distribution between load transfer members in the composite section was investigated by a nonlinear finite element analysis. The research results show that the stresses of steel plate, concrete and perforated rebar in a shear connector are on a low level. The relative slip between steel box and concrete is small, and both of them can collaboratively bear force. Besides, concrete, steel plate and shear connectors in the composite section are all in an elastic stage, and their stress distributions are uniform, indicating that the structure has a high safety margin. The steel-concrete composite section can effectively transfer load, and load distribution is reasonable as bearing plate and shear connectors share half of the load respectively.