Numerical modeling of steel–concrete composite structures

Steel–concrete composite structures are diverse in form and are widely used in industrial and civil infrastructures. To effectively simulate nonlinear behavior of composite structures under vertical load and horizontal earthquake action, a group of material constitutive models suitable for concrete in composite structures, concrete‐filled steel tubes that consider restraining effect, steel bars, and steel plates are developed via the User subroutine to define a material's mechanical behavior (UMAT) of a large‐scale finite element program ABAQUS based on extensive research. Based on analytical results, a section analysis method is proposed for round‐end sections, which is integrated into a fiber beam‐column model of steel–concrete composite structures in combination with the existing fiber discretization program. To verify the accuracy and applicability of the proposed fiber beam‐column model, trial computation is performed with the present fiber model versus PQ‐fiber model and OpenSees fiber beam‐column element. Comparison with extensive tests shows that the present fiber model has good accuracy and applicability.