基于车流统计的预应力混凝土连续梁桥疲劳性能评价

为研究车辆反复作用下在役预应力混凝土连续梁桥的疲劳损伤情况,对车流信息进行统计,确立标准疲劳车辆模型。建立全桥有限元模型,计算在一辆三轴标准疲劳车作用下沿全桥纵向不同位置混凝土和预应力筋的疲劳损伤度,可知边跨跨中底板预应力筋的疲劳损伤最大。计算在当前车流量,标准疲劳车辆一般运行状态下边跨跨中底板预应力筋的疲劳损伤度,得知其累计疲劳损伤较小,不会发生疲劳破坏;考虑到裂缝、车流量增长和车辆超重超载对桥梁疲劳损伤的影响,以2倍车重的6轴标准疲劳车作为超重车,从桥梁疲劳破坏层面推算出日均超大型、超重车数量不应超过382辆。

Fatigue Performance Evaluation for Prestressed Concrete Continuous Beam Bridge Based on Statistics of Traffic Flow

To investigate into the fatigue damage of a concrete continuous beam bridge in service under vehicle load,we built models of standard fatigue vehicles according to traffic flow statistics,and subsequently established a finite element model of the bridge.By calculating the fatigue damage of concrete and prestressed tendons at different longitudinal sections along the bridge under standard three-axle vehicles running through the whole bridge deck,we found that the fatigue damage of prestressed reinforcement at the first span floor is the largest. Moreover,under the present traffic flow of standard fatigue vehicles with ordinary spacings,the fatigue damage of bridge of the first span floor is small,with no fatigue failure.