基于模态柔度的损伤连续梁桥虚拟荷载试验方法研究  

Research on virtual load test method for damaged continuous beam bridges based on modal flexibility

作　　者：张方圆 亓兴军 黄岩 张炜 ZHANG Fangyuan;QI Xingjun;HUANG Yan;ZHANG Wei(School of Traffic Engineering,Shandong Jianzhu University,Ji’nan,Shandong 250101,China;Ji’nan Transportation Development Center,Ji’nan,Shandong 250303,China;Ji’nan Traffic Engineering Quality and Safety Center,Ji’nan,Shandong 250303,China)

机构地区：[1]山东建筑大学交通工程学院,山东济南250101 [2]济南市交通运输事业发展中心,山东济南250303 [3]济南市交通工程质量与安全中心,山东济南250303

出　　处：《河北工业科技》2024年第6期434-442,共9页Hebei Journal of Industrial Science and Technology

基　　金：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)。

摘　　要：为了快速评估连续梁桥承载能力和实际运营状态,提出基于模态柔度的虚拟荷载试验方法。以某实际工程(40+40+40)m的3跨连续梁桥为研究对象,采用数值模拟方法对其进行深入分析;将主梁单元的弹性模量折减30%模拟梁桥损伤,在白噪声激励下,运用SSI(stochastic subspace indentification)模态参数识别技术识别损伤梁桥的模态参数,进一步构建位移柔度矩阵;设计虚拟荷载试验方案,预测损伤梁桥在虚拟荷载下的模态挠度,计算结构校验系数。结果表明:环境激励下,只需在3跨连续梁桥四分点截面布置42个测点即可准确识别连续梁桥的动力特性参数;仅需前6阶模态参数即可预测虚拟荷载试验下连续梁桥关键截面的模态挠度;偏载、中载工况下3跨连续梁桥的结构校验系数均大于1,表明梁桥的承载能力不满足设计要求,需要及时维修养护。基于模态柔度的虚拟荷载试验方法在评估3跨连续梁桥的实际承载能力领域有一定应用潜力,可为工程实践提供可靠的技术支持。In order to quickly evaluate the bearing capacity and actual operating status of continuous beam bridges,a virtual load test method based on modal flexibility was proposed.Taking a 3-span continuous beam bridge of a certain actual project(40+40+40)m as the research object,numerical simulation methods were used for in-depth analysis.The elastic modulus of the main beam unit was reduced by 30%to simulate the bridge damage,and SSI modal parameter identification technology was used to identify the modal parameters of the damaged bridge under white noise excitation to construct the displacement flexibility matrix.A virtual load test plan was designed to predict the modal deflection of damaged bridge under the virtual load,and the structural verification coefficient was calculated.The results show that under environmental excitation,only 42 measuring points need to be arranged at the quarter point section of a 3-span continuous beam bridge to accurately identify the dynamic characteristic parameters of the continuous beam bridge;Only the first 6 modal parameters are needed to predict the modal deflection of key sections of continuous beam bridges under virtual load tests;The structural verification coefficients of the 3-span continuous beam bridge under unbalanced and medium load conditions are all greater than 1,indicating that the bearing capacity of the bridge does not meet the design requirements and requires timely maintenance.The virtual load test method based on modal flexibility has certain application potential in evaluating the actual bearing capacity of 3-span continuous beam bridges,can provide reliable technical support for engineering practice.

关 键 词：桥涵工程 环境激励 模态柔度矩阵 模态挠度 虚拟荷载试验 

分 类 号：U446[建筑科学—桥梁与隧道工程]