基于车桥耦合振动的波形钢腹板箱梁体外预应力束疲劳损伤评估

基于ANSYS建立精细化波形钢腹板箱梁桥数值模型,开展体外束疲劳分析。利用MATLAB编制了考虑车辆类型,行车位置、速度、车头距及轴重等因素的随机车流程序。采用雨流计数法计算24小时内随机车流作用下体外束应力等效应力幅以及等效应力循环次数。修正Muller研究结果,提出应力比低于0.035且考虑侧向弯曲磨损作用下的钢绞线S-N公式。利用Miner累积损伤准则并考虑冲击系数的影响,推算波形钢腹板箱梁桥体外预应力束的疲劳损伤度及剩余疲劳使用寿命,同时分析了桥梁跨径对体外束疲劳损伤的影响。研究结果表明,移动荷载对不同位置处体外束应力影响线的大小顺序为：中跨跨中位置＞边跨跨中位置＞中跨1/4跨位置,中跨跨中位置处的体外束应力受到的车辆荷载的影响较大;随机车流对体外束产生的疲劳损伤随跨径增加而减小。

Fatigue Damage Assessment of External Prestressed Beam of Corrugated Steel Web Box Girder Based on Vehicle-Bridge Coupling Vibration

The ANSYS finite element software was used to establish a refined numerical model of corrugated steel web box girder bridges, and to perform external beam fatigue analysis. Using MATLAB, a random traffic flow program was prepared considering factors such as vehicle type, driving position, speed, head distance and axle load. The rain current counting method was used to calculate the equivalent stress amplitude of external beam stress and the number of equivalent stress cycles under the action of random vehicle flow within 24 hours. Modified Muller"s research results, put forward the S-N formula of steel strands with stress ratio lower than 0.035 and considering lateral bending wear. Using the Miner cumulative damage criterion and considering the impact of the impact coefficient, the fatigue damage degree and remaining fatigue life of the external prestressed beam of the corrugated steel web box girder bridge are calculated, and the effect of the bridge span on the external beam fatigue damage is also analyzed. The results show that the order of the effect of moving loads on the external beam stress at different positions is: mid-span mid-position> side span mid-position> mid-span 1/4 span position, and mid-span mid-span external beam stress The impact of the vehicle load is greater; the fatigue damage of the external beam caused by random traffic flow decreases with the increase of the span.