Abstract: As a new bridge type, integral bridge can significantly reduce the long term maintenance cost, and its application should be encouraged in China. However, there is great uncertainty about the dynamic performance of integral abutments during earthquake. This paper presents the findings from a dynamic numerical simulation about a typical integral bridge. The influence of seismic peak acceleration, abutment height, and bridge deck length has been investigated. The effects of two mitigation methods, e.g. installation of a flexible layer and reinforced soil behind the abutment, have also been discussed. The results show that the traditional M-O method adopted in the current bridge abutment design code cannot give a reasonable prediction about the dynamic earth pressure behind integral abutment, which would lead to an unsafe design. Although a flexible layer can reduce the earth pressure, the deformation and bending moments will increase. Reinforcement can provide horizontal tensile forces to the abutment, leading to reduce abutment deformation and bending moments.

Key words: integral bridge abutment, earthquake response, dynamic earth pressure, flexible layer, soil reinforcement