索塔试验段二次张拉锚下应力监测与分析  

STRESS MONITORING AND ANALYSIS OF SECONDARY TENSIONING PRESTRESSED STEEL STRANDS FOR MAIN TOWER TEST SECTION OF CABLE-STAYED BRIDGE

作　　者：王家飞 张翔[2] WANG Jiafei;ZHANG Xiang(Construction Quality and Safety Supervision Station of Ninghai County,Zhejiang Ningbo 315600,China;Civil Engineering Testing Center of Zhejiang University,Hangzhou 310058,China)

机构地区：[1]宁海县建筑工程质量安全监督站,浙江宁波315600 [2]浙江大学土木工程测试中心,杭州310058

出　　处：《低温建筑技术》2022年第9期89-94,共6页Low Temperature Architecture Technology

摘　　要：混凝土斜拉桥索塔锚固区通常施加大吨位直线和环形预应力束,其预应力损失规律及钢束伸长量不同于常规梁板纵向预应力钢束。为研究索塔锚固区直线束和环形束张拉过程的预应力损失规律,文中针对某混凝土斜拉桥索塔锚固区足尺模型,重点分析了孔道摩阻损失、锚圈口摩阻损失、锚头回缩损失及钢筋松弛等预应力损失影响因素,定量分析锚下有效应力的大小。针对锚固回缩引起的预应力损失,采用低回缩二次张拉预应力锚具,能够补偿第一次张拉时的部分预应力损失,二次张拉后预应力总损失率在11%左右,为类似工程提供了经验。Large tonnage linear prestressed tendons and annular prestressed tendons are usually applied in the an⁃chorage zone of the cable tower of concrete cable-stayed bridge,in which prestress loss law and tendon elongation are different from those of conventional longitudinal prestressed tendons.The full-scale model test section of the ca⁃ble tower anchorage zone of a concrete cable-stayed bridge was studied to obtain the law of prestress loss during the tensioning of straight and circular tendons.The influencing factors of prestress loss such as duct friction loss,anchor ring mouth friction loss,anchor head retraction loss,and reinforcement relaxation were analyzed,and the effective stress under the anchor is quantitatively analyzed.For prestress loss caused by anchor retraction,the use of low re⁃traction secondary tensioning prestressed anchorage can compensate for the loss of partial prestress during the first tensioning,in which the total loss of prestress after secondary tensioning is about 11%.The results may provide the reference for similar projects.

关 键 词：二次张拉 锚下应力 监测 预应力损失 

分 类 号：TU378.1[建筑科学—结构工程]