钢箱拱双向倾斜吊杆锚固连接构造的弯拉疲劳特性及其构造优化

Bending Tension Fatigue Characteristics and Structural Optimization of Steel Box Arch with Two-way Tilting Boom Anchoring Connection Structure

吊杆作为系杆拱桥的关键受力构件,为分析双向倾斜吊杆锚固连接构造在服役期间的车致振动弯拉疲劳特性,以某1-188 m跨空间网状吊杆钢箱系杆拱桥为依托,通过建立三维有限元全桥模型及双轴车辆简化模型,分别采用桁架、梁单元对吊杆进行模拟,求解桥面不平整度激励下的吊杆车-桥耦合振动。结果表明:该桥各吊杆中梁端短吊杆应力值较大,跨中长吊杆应力值达到最大,网状吊杆倾向梁端方向应力幅大于倾向桥跨方向;同一吊杆下锚固端面外、面内转角分别约为上锚固端的2.3、1.7倍。为适应面外转角变形,建议相应调整梁上耳板孔及吊杆下端叉耳孔直径。相比于桁架单元,梁单元模拟吊杆计算的损伤度更大,跨中区域吊杆更易出现疲劳损伤。

The boom is an important stress-bearing component of a bowstring arch bridge.In order to analyze the fatigue characteristics of vehicle-induced vibration bending tension of the two-way tilting boom anchor connection structure during service,based on a 1-188 m span spatial mesh boom steel box bowstring arch bridge,and by establishing 3D finite element bridge model and double-shaft vehicle simplified model,the truss and beam element are used to simulate the boom,which solve the vehicle-bridge coupling vibration of boom under the unevenness of the bridge deck.The results indicate that the stress value of the short boom at the beam end of each boom of the bridge is relatively high,and the stress value of the long boom at the mid span reaches its maximum.The stress amplitude in the direction of the mesh boom towards the beam end is greater than that towards the bridge span direction.The outer and inner corners of the anchoring end face under the same boom are approximately 2.3 and 1.7 times that of the upper anchoring end.To adapt to the deformation of the external corner,it is recommended to adjust the diameter of the ear plate hole on the beam and the fork ear hole at the lower end of the boom accordingly.Compared to the truss element,the damage degree calculated by beam element simulation boom is greater,and the boom in mid-span area is more prone to fatigue damage.