Analytical and Numerical Analysis of Additional Stress in Foundation of Bridge Approach Embankment

A good estimation of additional stress of a bridge approach foundation overlying embankment is of great importance in order to accurately calculate the differential settlements of foundation due to the axisymmetric distribution of the additional stress. Current design method commonly adopted in road and railway engineering in China is derived from the classical elastic theory and simply considers the embankment load by its self-weight (γh) without taking into account the influence of the width-to-height ratio. This may lead to an overestimation of additional stress and consequently an uneconomical overdesign. This study attempts to mitigate the gap by developing a new analytical solution. Based on the Boussinesq’s elastic theory, the proposed solution considers a constrained boundary condition associated with bridge abutment and incorporates a new concept of ground reaction, which takes into account the embankment load including the influence of the embankment width-to-height ratio. The proposed solution was finally validated by numerical analysis and shows a better performance in terms of additional stress estimation over the traditional calculation method. Overall, the proposed method proved to be a better alternative tool for the design of bridge approach embankment.