Research On The Improvement Of The Anti-collision Performance Of The Corrugated Guardrail For The Middle Pier Of Cross-line Bridge

The impact of out-of-control vehicles on the piers in the medial strip not only threatens the safety of the cross-line bridge structure,but also causes huge losses of life and property.Therefore,it is urgent to carry out research on the protective measures of the middle pier of the cross-line bridge.The protective fence of this section must have a good blocking performance,which can prevent large trucks and cars from rolling over and hitting the middle pier and the middle pier.The guardrail in this section is close to the pier and its lateral deformations are limited.Therefore,the guardrail is required to intercept and guide the vehicle back to the traffic lane within a small deformation.This article carried out a collision simulation analysis by establishing a "guardrail-vehicle" finite element model.A improved guardrail scheme suitable for the protection of the middle pier of the over-line bridge was proposed,which combined three improved forms.The main research contents and results are as follows:(1)Increasing the height of the guardrail to improve the barrier ability of the guardrail to prevent trucks from rolling over and hitting the bridge pier.The collision simulation analysis of large trucks hitting the heightened wave beam guardrail was carried out in this paper.Studies had shown that after the height of waveform beam steel guardrail increased,the maximum lateral displacement of the top of the guardrail column increased significantly,and the deformation area of waveform beam plate also expanded.The guardrail height would affect the maximum dynamic dumping value and the dumping angle of the vehicle.As the height of the test guardrail increased,the vehicle inclination angle decreased and the maximum dynamic inclination value decreased.(2)Using additional beams to improve the barrier function of the guardrail and to prevent cars from drilling under the guardrail and then hitting the bridge pier.In this paper,the collision simulation of a car hitting a double-layer beam slab guardrail was carried out.Studies shown that adding guardrail beams could increase the rigidity of the guardrail and reduce the deformation of the guardrail.At the same time,it could also increase the energy loss during the impact by increasing the contact surface between the beam and the front of the car and the friction of the car body.In addition,after the guardrail was equipped with beams,it could prevent cars from passing through under the guardrail and also the column from blocking the wheels.The additional beam plate of the guardrail prevented the sudden energy loss of the vehicle.(3)Using dense columns to reduce the lateral deformation of the guardrail and prevent vehicles from hitting the bridge piers.Through the establishment of a "guardrailvehicle" finite element model,the research on the influence of the dense column on the protection capability of the guardrail system was carried out.This study showed that the overall rigidity of the double-height guardrail system was greatly improved after columns were densified,and the anti-impact ability of the vehicle was greatly improved.The maximum lateral deformation of the guardrail column and the deformation of the corrugated beam plate deformation area were significantly reduced.However,while increasing the rigidity of the guardrail system,it would also increase the acceleration of the occupants during the impact and increase the damage to the occupants.The spacing of the columns would also affect the maximum dynamic dumping value and the camber angle of large trucks.The distance between columns was reduced,and the maximum dynamic dumping of the vehicle and the camber angle of the vehicle significantly reduced.