大跨预应力混凝土连续梁桥双墩顶升计算分析  

Calculation and Analysis of Double-Pier Lifting for a Long-Span Prestressed Concrete Continuous Girder Bridge

作　　者：李庆收 LI Qingshou(China Railway 14th Bureau Group Corporation Limited,Ji'nan 250101,China)

机构地区：[1]中铁十四局集团有限公司,山东济南250101

出　　处：《国防交通工程与技术》2024年第4期31-35,26,共6页Traffic Engineering and Technology for National Defence

摘　　要：研究连续梁桥局部桥墩顶升时主梁关键截面混凝土应力和预应力钢筋应力变化规律,确保顶升高度在满足主梁安全的前提下能顺利完成支座更换,具有很重要的实际意义。以某三跨预应力混凝土连续梁桥震后修复工程为例,采用Midas civil建立该桥有限元模型,进行双墩同时顶升的计算分析,研究各支座反力、梁体上下缘应力及预应力钢筋应力的变化规律。结果表明:在满足支座更换高度要求下双墩顶升,各支座反力均未超过其承载能力,梁体翼缘应力及预应力钢筋应力均未超过其各自的设计应力,结构安全。间隔顶升时,中间顶升墩处下翼缘压应力最大,上翼缘产生拉应力;同时顶升两中墩时,成桥状态梁体应力变化较大,两种工况均为双墩顶升时的不利工况。双墩顶升时,梁体翼缘混凝土应力是影响主梁安全的主要控制因素,在施工时应该加强不同工况下各自关键截面处的应力监控。During the process of local pier lifting in continuous girder bridges,accurately analyzing the variation patterns of concrete stress and prestressed steel stress at critical sections of the main girder is crucial.It ensures efficient completion of bearing replacement while ensuring the safety of the main girder.This paper takes a post-earthquake repair project of a three-span prestressed concrete continuous girder bridge as an example.The bridge's finite element model is established in Midas Civil software to analyze the variation patterns of bearing reactions forces,stresses in girder flanges and prestressed steel reinforcements during the simultaneous lifting of both piers.The results indicate that during the simultaneous lifting of both piers to the required height for bearing replacement,all the bearings reaction forces did not exceed their bearing capacity.Simultaneously,the stresses in the girder's flanges and the prestressed steel reinforcements did not exceed their respective design limits.This confirms the overall safety of the bridge structure during the lifting process.Further comparative analysis revealed that using the interval lifting method resulted in the maximum compressive stress at the lower flange of the middle lifting pier,with tensile stress appearing at the upper flange.In contrast,simultaneously lifting of both intermediate piers caused more pronounced stress variation in the girder of the completed bridge structure.Therefore,both of these conditions are considered unfavorable conditions during dual-piers lifting.During double-pier lifting,the stress in the concrete of the beam flanges is the primary factor affecting the safety of the main beam.Therefore,during construction,it is crucial to enhance stress monitoring at critical sections under different conditions to ensure the safety and manageability of the construction process.

关 键 词：大跨预应力混凝土连续梁桥 双墩顶升 有限元分析 支座反力 承载力 

分 类 号：U445.4[建筑科学—桥梁与隧道工程]