汽车冲击荷载下自行车桥墩的受力变形分析

Stress and Deformation Analysis of Bicycle Bridge Piers under Vehicle Impact Loads

摘要:

为了解不同撞击力下厦门市自行车桥钢管混凝土桥墩的受力变形情况，基于美国AASHTO规范设计公式，计算小轿车、轻型汽车、中型汽车和重型汽车分别以40 kN/h、60 kN/h、80 kN/h、100 kN/h和120 kN/h不同撞击速度下对应的20个冲击荷载，并运用SAP2000有限元软件建立自行车高架桥三维模型进行模拟分析，结果表明：桥墩受小轿车和轻型货车冲击荷载作用时桥墩总体仍处于弹性状态；当中型货车以≥100 km/h、重型货车以100 km/h撞击时，桥墩局部进入塑性状态且最大塑性转角分别为0.28×10^-3 rad和0.64×10^-3 rad，但整体塑性变形在可控范围内；当重型货车以120 km/h撞击时，桥墩较大范围进入塑性阶段且很可能会直接影响桥梁的正常使用功能。

Abstract:

To analyze the deformation of concrete-filled steel tubular piers of bicycle bridges under different impact forces in Xiamen City, Fujian Province, 20 impact loads corresponding to different impact velocities of 40, 60, 80, 100, and 120 kN/h, from cars, light vehicles, medium vehicles, and heavy vehicles were calculated based on AASHTO code design formulas in America. A three-dimensional model of a bicycle viaduct is established using SAP2000 finite-element software. The results show that the pier is still in an elastic state when it is subjected to the impact load of a car and light truck. Under the impact of a medium-size truck with velocity ≥ 100 km/h or that of a heavy truck with velocity=100 km/h, the pier enters the plastic state and the maximum plastic rotation angle is 0.28E-3 rad and 0.64E-3 rad, respectively, but the overall plastic deformation is within the controllable range. When a heavy truck impacts with 120 km/h, the pier will enter the plastic stage in a large range, and this will probably directly affect the normal service function of the bridge.