考虑随机车载-风载联合作用的斜拉桥拉索疲劳可靠性分析

Fatigue Reliability Analysis on Cable of Cable-stayed Bridge Under Random Vehicle Load and Wind Load

以某大跨斜拉桥为工程背景,对随机车载与风载联合作用下的斜拉索疲劳可靠性进行了分析。首先,依据交通调查数据,建立随机交通荷载模型,基于桥位处多年风速统计资料,建立大桥风载概率模型;然后,采用自编的风-车-桥动力响应分析程序,实现随机车载与风载联合作用下的拉索应力谱计算分析;最后,基于累积损伤理论和Monte-Carlo法开展拉索的疲劳可靠度和疲劳寿命分析。研究结果表明:风载对斜拉索疲劳可靠度影响显著,且该影响由短索到长索呈不断增大的趋势;考虑车载-风载联合作用的拉索疲劳寿命较仅考虑车载的情况下降2%～63%,平均达50%。

Taking a long span cable-stayed bridge as a project background,the fatigue reliability of cable stay in combination as random vehicle load and wind load was analyzed.The authors firstly,setup traffic and wind load probability models for the bridge based on the traffic survey data and long-term wind velocity data from bridge site;then calculated the stress spectrum of the cable stays under combining loads by running self-compiled wind-vehicle-bridge interaction dynamic response analysis program;finally,evaluated the fatigue reliability and fatigue life with help of cumulative damage theory and Monte-Carlo method.The result shows that the effect of wind load on the fatigue reliability of cable stay is significant,and the influence degree increases in accordance with the order from short cable to long cable.Compared with only vehicle load,the fatigue life of the cable under both vehicle and wind load decreases by the range from 2% to 63%,with an average ratio of 50%.