低等级混凝土护栏对厢式卡车撞击桥墩作用的影响规律

Influences of low-grade concrete barrier on van-type truck collision with bridge piers

为研究公路护栏对车辆撞击桥墩作用的影响规律,从而合理评估实际桥墩在车辆撞击下的安全性,采用有限元方法对大型箱式卡车(福特F800)撞击低等级混凝土护栏(新泽西护栏)以及护栏-桥墩系统进行了仿真模拟;重点考察了该卡车与护栏碰撞后的运动形态、护栏防护下的卡车-桥墩碰撞机理及车辆撞击力峰值特征等,并对护栏的防护作用作了进一步讨论。模拟结果表明:在护栏防护下,该箱式卡车对桥墩的撞击作用主要取决于货物撞击,而发动机一般不与桥墩发生碰撞;在某些撞击工况下,设置护栏时车辆对桥墩的撞击力峰值可能超过未设置护栏时的撞击力峰值,甚至达到后者2倍以上;当桥墩与护栏距离较近时(例如小于1.5 m),该低等级混凝土护栏对桥墩防车辆撞击可能起到负面作用。

In order to study the influence law of highway barrier on the impact effects of vehicle collision with bridge piers,so as to reasonably evaluate the safety of the actual pier under vehicle collision,finite element method was employed to carry out simulations of a large-size van-type truck(Ford F800)impacting with a low-grade concrete barrier(New Jersey barrier)and barrier-pier system.The motion pattern of the truck after collision with barrier,truck-pier collision mechanism under the protection of the barrier and the impact force peaks of the vehicle,etc.,were mainly investigated,and the protective effect of the barrier was further discussed.The simulation results show that under the protection of the barrier,the impact of this van-type truck on the pier depends mainly on the cargo impact,while the engine generally does not collide with the pier.Under certain impact conditions,the peak impact force of the vehicle on the pier may exceed the peak of the impact force when the barrier is not set,even more than twice the latter.When the pier is close to the barrier(e.g.,less than 1.5 m),this low-grade concrete barrier may have a negative effect on the pier against vehicle collision.