Systematic Analysis on Upper Structure-Pier-Pile Foundation of Highway Bridge under Strong Seismic Force and Necessity Judgment of Ground Stabilization

Abstract

The present authors have already clarified that the flexural moment due to the vertical seismic force ignored hitherto as an additional load besides the primary one by the horizontal seismic force is able to be a trigger of the collapse of a kind of bridge pier.The previous paper dealt with the protective basement region for the column and/or the highway bridge pier, determined on the basis of the design concept of the flexure-shear failure transition steel ratio; that is to say, the protective basement region has been formularized for the diagonal shear force as to the bridge pier. The present paper has made the necessity of stabilization from the viewpoint of the coefficient of horizontal subgrade reaction clear, considering the frequent phenomena of flexural failures of the foundation piles in the ground in recent years; in addition the impulsive reflected tensile stress wave generates the tensile failures across the sections of bridge pier and foundation pile. This paper lays emphasis on the impulsive compressive force and the successive reflected stress wave due to the huge seismic motion, the strengthening of bridge pier and/or foundation pile, and the soil stabilization in order to protect the flexural break of pile.