Analysis of Dynamic Response on Double-Column Bridge Piers of Mountainous Area based on the Collision of Rolling Stones

Anti-rolling stone collision design for mountain bridges is the key link of bridge design in mountainous area.However, the existing research of bridge structures based on collision bears limitations.Only a few studies on the dynamic response of bridge piers based on rolling stone collision are available.Explorations on the problem of the rolling stone colliding bridge piers are limited, and the anti-rolling stone collision design of bridge piers is blind.This study took the Chang Ba Bridge of Nan Chuan District located at Chongqing of China as a specific research object prototype.A simulation analysis of the dynamic response of double-column bridge piers under rolling stone collision was conducted in this study to improve the anti-rolling stone collision performance of bridge piers and reduce their damage under the rolling stone collision.This analysis utilized display dynamics analysis software ANSYS/LS-DYNA to establish the rolling stonepier collision model and extracted stress time-history and displacement curves of the key part of bridge pier structures.This study compared and analysed the dynamic response of the bridge pier under different initial velocities and different collision positions of the rolling stone.The results demonstrate that the maximum value of stress variation of the bridge pier structure decrease with the reduction of the distance from the collision position to the bottom of the bridge pier when the bridge pier collided by rolling stones with the same initial velocity and different collision positions.This phenomenon indicates that the dynamic response of the bridge pier under the rolling stone collision is affected by the bottom constraint of the bridge pier.The stress of the bridge pier concentrates on the connecting part of the bridge pier and the coupling beam.This phenomenon indicates the vulnerability of the connecting part of the bridge pier and the coupling beam, except for the collided area of the bridge pier.Maximum stresses of the longitudinal reinforcement and the stirrup don't exceed 35. Thus, the longitudinal reinforcement and the stirrup of the bridge pier don't reach yield strength and can still participate in force with the bridge pier concrete.Conclusions obtained in the study can provide theoretical references for the anti-rolling stone collision design of double-column piers in mountainous area.