Finite element analysis of progressive collapse resistance of precast concrete frame beam-column substructures with UHPC connections

Compared with reinforced concrete structure, precast concrete structure is prone to progressive collapse due to its poor continuity. The use of ultra-high performance concrete (UHPC) provides a feasible solution. To this end, investigate the influence of UHPC on the progressive collapse resistance of precast beam-column substructures, the finite element model of precast beamcolumn substructures with UHPC connections was established. The model was validated using available experimental data. Specifically, the cohesive-Coulomb friction model was used to simulate the interface behavior between precast concrete and cast-in-place concrete, and the metal ductile damage model was used to simulate rebar failure. The finite element simulation results show good agreement with experimental results, with an average error of less than 5 %. Additionally, five sets of full-scale analysis models were designed to analyze the effect of cast-inplace UHPC on the progressive collapse resistance of precast beam-column substructures. The results indicated that UHPC enhances the compressive arch action (CAA) capacity and catenary action (CA) capacity of precast beam-column substructures. Parametric analysis was conducted based on these models. The results indicated that the increase of UHPC strength grade can improve the CAA capacity of the structure, but reduce the CA capacity. Interface roughness has a certain effect on CAA capacity, but has no obvious effect on CA capacity. Finally, the accuracy of existing analytical models in predicting the CAA and CA capacity of UHPC-connected precast beam-column substructures is evaluated. The research results can provide reference for the design and application of precast concrete structures connected by UHPC.