Progressive collapse resistance of local prestressed concrete sub-structures: Numerical analysis and theoretical verification

Abstract

The local prestressed concrete (LPC) structure is a structural form that combines the prestressed concrete (PC) span with the common reinforced concrete (RC) span, with significant asymmetry. Currently, there is insufficient research on the progressive collapse resistance of LPC structures. To investigate the progressive collapse mechanism of LPC structures, a parametric analysis was conducted by using the finite element software OpenSEES. Based on the failure mode of LPC structures, the proposed method predicted the limit state by considering displacement coordination, force equilibrium, and the influence of the plastic hinge regions. The research showed that LPC structures exhibited a distinct transition action stage (TAS) between the compressive arch action stage (CAAS) and catenary action stage (CAS), which distinguished them from the symmetrical structures. Increasing the strand area could significantly improve the catenary action (CA) of the LPC structure and extend the TAS. Lengthening the PC part also improved CA and allowed the structure to progress into TAS and CAS earlier. By increasing the length of the RC part, the compressive arch action (CAA) could be strengthened, while the duration of CAAS was extended. The theoretical prediction method proposed in this study can effectively predict the ultimate displacement and ultimate resistance of LPC structures.