交通量持续增长下既有拱桥车载效应极值概率

The probability of vehicle-effect extreme value of existing arch bridges with continuous increase of traffic volume

为了准确评定交通量持续增长下既有桥梁的运营安全水平,提出基于“时间划分?极值概率累加”的改进广义极值分布,捕捉到了车载效应的时变特征,并经典型算例验证了该方法的适用性。基于WIM实测车流数据,预测了交通量增长和超载率限制下某拱桥的最大弯矩。研究结果表明:交通量的增长会导致桥梁车载效应极值显著增大。当年交通增长率为2%~4%时,既有拱桥弯矩的最大值增加10%~15%;当年交通量增长率为4%时,该拱桥弯矩的最大值将大于其设计标准值,应对桥梁车流量进行交通管制。超载率限制对桥梁车载效应极值有显著影响。当超载率上限为50%~200%时,该拱桥弯矩的最大值减小至70%~82%。

In order to accurately assess the operational safety level of existing bridges under the continuous growth of traffic volume,a time-varying feature of the improved generalized extreme value distribution(GEV)based on“time division-extreme probability accumulation”is proposed,and the applicability of the method is verified by a typical example.Based on WIM measured traffic data,the maximum bending moment of existing arch bridges under traffic volume growth and overload rate limit is predicted.The results show that the increase of traffic volume leads to a significant increase in the extreme value of the on-board effect of the bridge.When the annual traffic growth rate is 2%~4%,the maximum bending moment of the existing arch bridge increases by 10%~15%.When the annual traffic growth rate is 4%,the maximum bending moment of the arch bridge will be greater than the design standard value,and the traffic volume of the bridge should be controlled.The overload rate limit has a significant impact on the extreme value of the on-board effect of the bridge.The limit of overload rate has a significant impact on the extreme value of bridge vehicle effects.When the upper limit of overload rate is 50%~200%,the maximum bending moment is reduced to 70%~82%.