Study on Progressive Collapse Behavior of SRC Column-Steel Beam Hybrid Frame Based on Pushdown Analysis

Abstract EN

To investigate the progressive collapse behavior of Steel Reinforced Concrete (SRC) column-steel beam hybrid frame after the failure of key structural elements, a PQ-Fiber model for an 8-storey structure is established in ABAQUS program.

Nonlinear dynamic and static pushdown analysis are carried out after the failure and removal of the bottom-middle and bottom-corner columns.

Numerical results of both methods agree well with each other.

Results show that SRC column-steel frame has good resistance to progressive collapse under dynamic instantaneous load.

After sudden removal of a bottom middle column, the development of structural collapse exhibits two mechanisms, the beam mechanism and the catenary mechanism.

When the structure is within small deformation range, the collapse resistance of the residual frame is provided by the beam bending moment capacity, which is beam mechanism.

For large deformation situation, the collapse resistance is mainly provided by the beam tensile strength, which is catenary mechanism.

However, with the removal of a bottom corner column, the residual structure only undergoes the beam mechanism even for large deformations.

For future practical applications, the influence of the steel ratio, steel section size, and the vertical position of the removed key components are investigated through a detailed parametric study.