Research on Existing Bridges Rapid Load-Lifting Technology with UHPC in Highways Reconstruction and Expansion Projects

There are a large number of small and medium-span bridges in the highway reconstruction and expansion projects. These bridges have been used for at least 20 years. Due to the design according to the old code the ultimate bearing capacity is generally insufficient after the reconstruction and expansion. This paper selects hollow-core slab bridges that account for more than 80% of the reconstruction and expansion projects as the research object, carefully evaluates the specific reasons for the insufficient bearing capacity of small and medium-span bridges, designs a plan for rapid loading-lifting of existing bridges, and uses theoretical analysis. Then, the comprehensive method of finite element calculation analyzes and studies on the reinforced bridge’s bearing capacity. The research shows that the existing small and medium-span bridges in the reconstruction and expansion project are mainly manifested by insufficient shear-bearing capacity after the load is improved. Using the bridge deck to add the UHPC cast-in-place layer (participating in the structural internal force) can effectively improve the existing old bridge Shear resistance capacity, and UHPC cast-in-situ layer shear reinforcement efficiency is much greater than that of ordinary concrete.