深中通道60 m箱梁底板束锚圈口转角对预应力损失影响研究  

Influence of Rotation Angle of Prestressing Tendons Anchor Ring in Bottom Slabs on Prestress Loss of 60 m-Long Box Girder of Shenzhen-Zhongshan Link

作　　者：金志坚 陈善行 盛建军 鲁立涛 JIN Zhi-jian;CHEN Shan-xing;SHENG Jian-jun;LU Li-tao(Shenzhen-Zhongshan Link Administration Center,Zhongshan 528400,China;Guangdong Provincial Road Construction Co.,Ltd.,Guangzhou 510660,China;Guangdong Shengxiang Traffic Engineering Testing Co.,Ltd.,Guangzhou 511400,China)

机构地区：[1]深中通道管理中心,广东中山528400 [2]广东省公路建设有限公司,广东广州510660 [3]广东盛翔交通工程检测有限公司,广东广州511400

出　　处：《世界桥梁》2023年第S01期34-40,共7页World Bridges

基　　金：广东省重点领域研发计划项目(2019B111105002)。

摘　　要：深中通道60 m预制箱梁为预应力混凝土结构,箱梁预应力钢束分为腹板、顶板、底板束和底板合龙束。针对首片预制箱梁底板BD2a、BD2b束YJM15-15锚锚下有效预应力值偏低且均匀性较差的问题,对预应力钢束理论有效预应力及考虑锚圈口转角的预应力损失进行计算,分析锚圆口转角对预应力损失的影响,并将理论标准值与锚下有效预应力实测值进行对比,提出保证锚下有效预应力的措施。结果表明:锚圈口转角越大,锚圈口摩阻损失率越大,锚下有效预应力越小;BD2a、BD2b束锚下有效预应力实测值与理论标准值偏差较大,进行退索处理后量测锚圈口转角,根据实测锚圈口转角平均值计算锚下有效预应力理论标准值为157 kN,与实测值较为接近;张拉施工前,需对锚板与喇叭口处残留混凝土或外伸过长波纹管及时清理整改,使张拉时钢绞线经过锚板与喇叭口的转角接近设计角度要求或者不大于4°。In the 60 m-long prestressed concrete box girders of the Shenzhen-Zhongshan Link,prestressing tendons as well as closure tendons are implemented in the webs,top and bottom slabs.The effective prestress beneath the anchor YJM15-15 of the effective prestressing tendons BD2a and BD2b in the starter bottom slab is low and with poor uniformity.To address this issue,the theoretical effective prestress and the prestress loss considering the anchor ring rotation angle were calculated,the influence of the rotation angle on pretress loss was analyzed,and the theoretical value was compared with the measured value,based on which the treatments to ensure the effective prestress beneath the anchor were proposed.It is shown that the bigger the rotation angle,the greater the loss of the friction of the anchor ring,and the smaller the effective prestress.There is a big difference between the measured and theoretical values of the effective prestresses of the prestressing tendons BD2a and BD2b.After the prestressing tendons were pulled out,the rotation angle of the anchor ring was measured,together with the measured average rotation angle of the anchor ring,the effective theoretical prestress beneath the anchor was calculated to be 157 kN,close to the measured value.Before tensioning,the waste concrete on the anchor plate and at the bell mouth of the anchor as well as the protruding corrugated ducts required to be timely cleaned up and treated,to make sure that the rotation angle of the prestressing tendons pass through the anchor plate and the bell mouth approximates the design values or less than 4°.

关 键 词：跨海桥梁 预制箱梁 预应力钢束 有效预应力 预应力张拉 锚圈口转角 摩阻损失 预应力损失 

分 类 号：U441[建筑科学—桥梁与隧道工程] U445.471[交通运输工程—道路与铁道工程]