先张PC梁抗裂性能及优化措施研究  

Research on Crack Resistance and Optimization Measures of Pretensioned PC Girders

作　　者：孙宝林 冯文杰[2] 杨永清[3] 严猛 孙竞飞 SUN Baolin;FENG Wenjie;YANG Yongqing;YAN Meng;SUN Jingfei(Key Laboratory of Roads and Railway Engineering Safety Control(Shijiazhuang Tiedao University),Ministry of Education,Shijiazhuang 050043,China;Shijiazhuang Tiedao University,Shijiazhuang 050043,China;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Sichuan Jiaoda Engineering Testing Consulting Co.,Ltd.,Chengdu 610031,China)

机构地区：[1]道路与铁道工程安全保障教育部重点实验室(石家庄铁道大学),河北石家庄050043 [2]石家庄铁道大学,河北石家庄050043 [3]西南交通大学土木工程学院,四川成都610031 [4]四川交大工程检测咨询有限公司,四川成都610031

出　　处：《桥梁建设》2025年第2期153-160,共8页Bridge Construction

基　　金：中国博士后科学基金项目(2023M742427);河北省自然科学基金项目(E2023210114)。

摘　　要：为研究先张预应力混凝土(PC)梁在快速施工和超量预应力损失下的抗裂性能,以某线路先张PC简支梁桥为背景进行研究。首先采用试验和理论分析相结合的方法研究梁体的短期和长期抗裂性能,分析薄弱梁体的开裂风险;然后从设计和施工方面提出优化措施;最后进行优化措施试验验证。结果表明:常规状态下,先张PC梁的短期和长期抗裂性能均满足设计要求;在长线法施工的3榀梁中,中间梁体的抗裂储备有限,存在一定程度的开裂风险;可采取下调钢绞线弯转角、更换转向器、降低长线梁榀数和延后放张等优化措施;优化后中间梁体抗裂储备不足的问题得以解决,端部梁体的折线钢绞线预应力平均提高88 MPa,直线钢绞线预应力平均提高46 MPa,抗裂性能提升5%,较大程度解决了快速施工带来的超量预应力损失和抗裂问题。This study focuses on the crack resistance of pretensioned prestressed concrete(PC)girders under accelerated construction and excessive prestress loss.An existing simply-supported pretensioned PC girder bridge is used as a case.The short-and long-term crack resistance of the girder was tested and theoretically analyzed,and the cracking risk of the weak girder was discussed.Optimization suggestions were given from design and construction perspectives.Tests were conducted to verify the optimization measures.The results demonstrate that under regular loading conditions,the short-and long-term crack resistance of the pretensioned PC girders meets the design requirements.For the three girders manufactured by the long-line match casting method,the central girder owns limited crack resistant reserve,with likelihood of cracking risk.The suggested measures include reducing the deflection angles of the steel prestressing tendons,replacing deviators,reducing the number of long-line-match-cast girders,and delaying detensioning of prestressing tendons.After optimization,the crack resistance margin of the central girder is enlarged,the prestresses of the deflected prestressing tendons in the end girders and the straight prestressing tendons are improved by an average of 88 MPa and 46 MPa,respectively,as a result,the cracking resistance is improved by 5%,resolving the excessive prestress loss and crack resistance issues of the girders by the accelerated construction.

关 键 词：简支梁桥 先张预应力混凝土梁 超量预应力损失 抗裂性能 开裂风险 优化措施 试验验证 

分 类 号：U448.217[建筑科学—桥梁与隧道工程] TU757.13[交通运输工程—道路与铁道工程]