为探究虚拟静载试验方法评定大跨径斜拉桥主梁刚度的可行性,以某一斜拉桥为研究对象,对其进行静载试验和环境激励下的模态测试试验。设计主跨跨中截面中载和偏载试验,测量静载试验下各个测点的静力挠度；通过环境激励采集主梁的振动信息,识别模态参数,基于kriging插值方法对斜拉桥的实测振型进行模态扩展,预测斜拉桥主梁跨中截面在静载试验荷载作用下的模态挠度,与实测静载挠度对比；设计满足加载效率的虚拟静载试验方案,计算虚拟静载下的挠度校验系数,评估斜拉桥主梁刚度。结果表明：环境激励下的模态测试可以准确识别桥梁的模态参数信息；利用kriging插值方法扩展的前四阶振型预测桥梁的模态挠度,与实测静载挠度的相对误差小于10%,满足工程精度的要求,说明模态挠度应用于大跨径斜拉桥的工程准确性；虚拟静载试验方法与静载试验所得挠度校验系数相比,相差较小,评定结果均小于1.0,表明该斜拉桥主梁承载状况良好,充分说明了虚拟静载试验方法在正常交通下评定大跨斜拉桥主梁刚度具有较好的可行性与有效性。

In order to investigate the feasibility of virtual static load test method to evaluate the stiffness of the main girder of a large span cable-stayed bridge, a cable-stayed bridge was subjected to static load test and modal test under environmental excitation. Based on the modal parameters identified under the environmental excitation, the modal expansion of the measured vibration pattern of the cable-stayed bridge was carried out by applying the kriging interpolation method to predict the modal deflection of the span section of the cable-stayed bridge under the static load test, and compare the measured static deflection with the measured static load. The deflection calibration coefficients under virtual static load were calculated to evaluate the stiffness of the main girder of the cable-stayed bridge. The results show that the modal test under ambient excitation can accurately identify the modal parameters of the bridge; the relative error between the first four orders of vibration patterns predicted by the kriging interpolation method and the measured static load deflection was less than 10%, which meets the requirement of engineering accuracy and indicates the engineering accuracy of the modal deflection applied to large span cable-stayed bridges; the difference between the virtual static load test method and the static load test obtained deflection The difference between the virtual static load test method and the static load test deflection coefficient was small, and the evaluation results were less than 1.0, which indicated that the main girder of the cable-stayed bridge was in good bearing condition, fully demonstrating the feasibility and effectiveness of the virtual static load test method in evaluating the stiffness of the main girder of large-span cable-stayed bridge under normal traffic.

山东省交通运输厅科技计划项目(2022B06)；山东省企业技术创新项目(202250101726,202160101415)