车辆撞击作用下预制拼装桥墩动力响应数值分析

Numerical Analysis of Dynamic Response of Prefabricated Assembled Piers Under Vehicle Impact

为研究车辆撞击作用下预制拼装桥墩的动态响应与损伤,采用显式动力分析软件LS-DYNA建立具有滑移导向面的预制拼装桥墩三维实体分离式模型。与摆锤撞击试验结果进行对比,验证了有限元模拟方法的可靠性。基于该模型,探究了预制拼装桥墩与整体式桥墩的动力响应差异,并进一步分析撞击位置、节段数量、导向面的倾斜角度、初始预应力水平对撞击力和桥墩变形的影响规律,最后结合各国规范对比其等效撞击力值。结果表明:具有滑移导向面的预制拼装桥墩在车辆的撞击下,其位移响应模式为顶部节段围绕底部节段为中心产生摇摆行为;当预应力水平从10%提高到20%,顶部节段侧向位移减小程度达25%;我国规范给出的撞击力值偏小,当车辆速度大于等于80km/h时,卡车撞击该预制拼装桥墩得到的撞击力值均高于我国规范值。

To study the dynamic response and damage of prefabricated bridge piers under vehicle impact,an explicit dynamic analysis software LS-DYNA was used to establish a three-dimensional solid separation model of prefabricated bridge piers with sliding guide surfaces.The reliability of the finite element simulation method was verified by comparing it with the results of the pendulum impact test.Based on this model,the differences in dynamic response between prefabricated and integral bridge piers were explored,and further analysis was conducted on the impact position,number of segments,inclination angle of the guide surface,and initial prestressing level on the impact force and pier deformation.Finally,the equivalent impact force values were compared in accordance with national regulations.The results indicate that,under the impact of vehicles,the displacement response mode of prefabricated bridge piers with sliding guide surface is that the top segment oscillates around the center of the bottom segment.When the prestress level is increased from 10%to 20%,the lateral displacement of the top section decreases by 25%.The impact force values given in Chinese regulations are relatively small.When the vehicle speed is greater than or equal to 80km/h,the impact force values obtained from the truck hitting the prefabricated bridge pier are higher than the design impact force values given in Chinese regulations.