Impact of Demolition and Reconstruction of Huayudong Bridge on the Stability of Bank Slope

The Huayudong Bridge demolition and reconstruction project won the Gustav Lindenthal Medal for its pioneering construction technique of building a new arch while using the old bridge, and then dismantling the old bridge with the new arch. The Huangguoshu bank slope of the bridge was taken as the research object to explore the impact of this construction technique on the stability of bank slope. The lithology of the bank slope strata was determined through laboratory tests. Using ABAQUS software as calculation platform, the displacement changes of the bank slope under different bridge foundation loads were simulated and calculated for the two construction techniques of building-new-arch-first and dismantling-old-bridge-first. The stability of the slope under the two techniques was compared based on the displacement saltation criterion. The results show that under the condition of building-new-arch-first construction technique, the stability of the bank slope depends on the load of the new arch, and the old bridge foundation load has almost no impact on it. The critical load for bank slope deformation and instability is about 35 MPa. Thile under the condition of dismantling-old-bridge-first construction technique, the stability of the bank slope depends on the old bridge foundation load, and the critical load for bank slope deformation and instability is about 20 MPa. building-new-arch-first can provide a solid retaining wall-like support effect for the demolition of the old bridge, ensuring absolute safety during the demolition process, and thus offers relatively higher construction safety.