重车荷载作用的简支梁桥荷载效应极值预测

Extreme value prediction of load effect of simply supported beam bridge under heavy vehicle load

为了准确预测重车荷载作用的简支梁桥荷载效应极值,充分考虑了过桥重车的随机性特征和不同重车荷载事件出现的概率,基于经典极值理论,提出了不同重车荷载事件的组合广义极值分布(CGEV)极值预测方法,通过数学推导和数值算例证明了该方法的合理性.同时,以一座简支梁桥为工程背景,采用CGEV方法预测简支梁桥在重车荷载作用下的荷载效应极值.研究结果表明:采用CGEV方法预测桥梁的车致荷载效应极值精度较高且工程应用方便,最大预测误差为4%,而传统混合数据的单一广义极值分布(SGEV)的桥梁车致荷载效应极值预测误差最小为36.6%;简支梁桥的车致荷载效应可以基于同时过桥的重车数量划分荷载事件类型,其车致荷载效应极值主要受2辆重车过桥事件控制;为了保证简支梁桥的安全运营,建造时应有适当的安全储备,管养时应结合实际情况对过桥重车采取相应的限载措施.

In order to accurately predict the extreme value of load effect of simply supported beam bridge under the action of heavy vehicle load,the randomness of heavy vehicle and the probability of different heavy vehicle load events were fully considered.Based on the classical extreme value theory,a combined generalized extreme value distribution(CGEV)extreme value prediction method for different heavy vehicle load events was proposed.The rationality of this method was proved by mathematical derivation and numerical examples.At the same time,taking a simply supported beam bridge as the engineering background,the extreme value of load effect of simply supported beam bridge under heavy vehicle load was predicted by CGEV method.The results show that the CGEV method to predict the extreme value of vehicle induced load effect of bridge has high accuracy and convenient engineering application,the maximum prediction error of CGEV is 4%,while the prediction error of the conventional single generalized extreme value distribution(SGEV)is 36.6%.The vehicle induced load effect of simply supported beam bridge can be divided into load event types based on the number of heavy vehicles crossing the bridge at the same time,and the extreme value of vehicle induced load effect is mainly controlled by two heavy vehicles crossing the bridge.In order to ensure the safe operation of the simply supported beam bridge,there should be appropriate safety reserves during construction,and corresponding load limiting measures should be taken for the heavy vehicles crossing the bridge in combination with the actual situation.