Flood-induced shear failure and floating performance of UHPC box girder bridge using integrated CFD-FEM analysis

The vulnerability of bridges to flooding and debris impact has become a critical global concern, further intensified by climate change. This study investigates the flood-induced shear response of an ultra-high-performance concrete (UHPC) box-girder bridge without shear reinforcement, designed to temporarily float during extreme flooding and thereby enhance structural resilience and public safety. A sequential methodology was adopted using a 1:7.5 scaled UHPC box-girder bridge model, combining laboratory experiments and integrated CFD–FEM simulations to evaluate shear failure mechanisms under flood flow and debris impact. Laboratory experiments first assessed the bridge’s floating capacity and shear resistance under three loading scenarios—flow-only, debris-only, and combined flow–debris loading—at velocities ranging from 0.5 to 1.0 m/s. Complementary numerical analyses were then performed using computational fluid dynamics in ANSYS to predict hydrodynamic drag forces over a wider velocity range (0.5–16 m/s), which were subsequently transferred into a finite element framework to evaluate shear stress evolution. The results demonstrate that the bridge successfully transitioned into a floating state with only 120 mm of partial submersion from its total depth of 286 mm. Under flow-only conditions, shear stresses remained below the shear capacity of 10.6 MPa even at velocities up to 15.5 m/s. In contrast, debris impact significantly amplified hydrodynamic forces, reducing the critical velocity threshold to 3.5 m/s. Based on the shear failure index, critical velocities of 16 m/s, 7 m/s, and 3.5 m/s were identified for flow-only, debris-only, and combined loading conditions, respectively. These findings highlight debris as the dominant factor governing shear vulnerability and confirm the feasibility of the proposed semi-floating UHPC bridge as a sustainable, flood-resilient alternative to conventional bridge systems.

Text 127928.pdf - Published Version Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (11MB) Official URL or Download Paper: https://linkinghub.elsevier.com/retrieve/pii/S2590...

Actions (login required)

View Item