基于监测研究的大跨径连续刚构桥跨中下挠预测分析  

Prediction Analysis of Mid-span Deflection of Long-span Continuous Rigid Frame Bridge Based on Monitoring Research

作　　者：孙中洋 张显明 李功文 刘波 SUN Zhongyang;ZHANG Xianming;LI Gongwen;LIU Bo(China Merchants Chongqing Highway Engineering Testing Center Co.,Ltd.,Chongqing 400067)

机构地区：[1]招商局重庆公路工程检测中心有限公司,重庆400067

出　　处：《公路交通技术》2023年第5期120-128,共9页Technology of Highway and Transport

摘　　要：现行《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG 3362-2018)中,所用收缩徐变公式计算连续刚构桥梁的挠度与运营该类桥梁实际监测结果差异较大,首先采用有限元模拟计算法分析了规范中新增加粉煤灰掺量参数对桥梁结构挠度变化的敏感性,并计算了多种收缩徐变的影响因素对桥梁挠度的变化影响;然后依据运营桥梁长期监测结果,分析了不同运营时期连续刚构桥梁跨中挠度发展规律;最后建立了监测桥梁跨中实测挠度值与理论计算的倍数关系。结果表明:1)增加粉煤灰掺量,对实桥计算桥梁结构挠度敏感性大,且其随粉煤灰掺量的增加而缓慢减小;环境湿度、结构容重、混凝土加载龄期等对桥梁结构挠度均有明显关联性,实桥结构计算分析中应按实际采集数据进行分析;2)监测桥梁跨中挠度实测值是数值模拟预测计算值的2.83倍,据此,通过调整实桥模型参数对桥梁后期收缩徐变挠度可作出预测。该结果可供同类型桥梁施工监控经验预拱度的合理设置参考。In the current Specifications for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts(JTG3362-2018),the shrinkage and creep formula used to calculate the deflection of continuous rigid frame Bridges is quite different from the actual monitoring results of operating such bridges.Firstly,the sensitivity of the newly added fly ash content parameter to the bridge structural deflection is simulated by finite element method.The influence of various shrinkage and creep factors on the deflection of bridge is calculated.Then,according to the long-term monitoring results of operating Bridges,the development rules of mid-span deflection of continuous rigid frame Bridges in different operating periods are analyzed.Finally,the relationship between the measured deflection and the theoretical calculation of the midspan is established.The results show that:1) With the increase of fly ash content,the sensitivity of the deflection of the bridge structure is large,and it slowly decreases with the increase of fly ash content.The environmental humidity,structural bulk density and concrete loading age have obvious correlation to the deflection of bridge structure,and the actual collected data should be analyzed in the calculation and analysis of real bridge structure;2) The measured value of mid-span deflection of the monitored bridge is 2.83 times that of the numerical simulation prediction.The late shrinkage and creep deflection of the bridge can be predicted by adjusting the parameters of the real bridge model.The result can be used as a reasonable reference for setting the pre-arch degree of the construction monitoring experience of the same type of bridge.

关 键 词：连续刚构桥 跨中下挠 敏感性分析 变形监测 挠度预测 

分 类 号：U446[建筑科学—桥梁与隧道工程]