摘要
针对斜拉桥索塔锚固区传统钢绞线预应力体系存在布设复杂、预应力分布不均匀、锚下应力集中等问题,对采用无粘结预应力钢棒体系索塔锚固区的力学特性开展了研究。以洛溪大桥拓宽工程主桥为背景,采用ANSYS软件分别建立了该桥预应力钢棒体系及传统钢绞线预应力体系索塔锚固区节段有限元模型,对比了2种预应力体系索塔锚固区在2种荷载工况下(完成预应力张拉但未张拉斜拉索和斜拉索张拉后)混凝土塔壁横桥向应力、顺桥向应力、第一主应力和第三主应力。结果表明:2种荷载工况下,无粘结预应力钢棒体系具有足够的压应力储备;与传统钢绞线预应力体系相比,无粘结预应力钢棒体系锚固区的应力水平较低,混凝土塔柱的应力水平沿高度方向更为均匀,采用无粘结预应力钢棒体系索塔锚固区具有更优的力学性能。
Prestressing steel strands are usually applied in the cable-pylon anchorage zone of the cable-stayed bridge,however the uneven prestress distribution and stress concentration underneath the anchorage are critical issues.In this paper,the unbonded prestressing steel bars are introduced as an alternative to the prestressing steel strands,and based on the engineering practice of the Luoxi Bridge widening project,the mechanical properties of the unbonded prestressing steel bar system are investigated.Finite element models of the cable-pylon anchorage zones with prestressing steel bar system and conventional prestressing steel strand system were built up in ANSYS,to analyze the transverse and longitudinal stresses as well as the first and third principal stresses in the walls of the concrete pylon,when the tensioning of prestressing steel bars/strands was finished,but the stay cables had yet been tensioned and after the tensioning of stay cables,respectively.It is shown that under the aforementioned two loading conditions,the unbonded prestressing steel bar system has sufficient compressive stress margin,compared with the conventional prestressing steel strand system,the stress level in the cable-pylon anchorage zone with unbonded prestressed steel bars is lower,the stress distribution evenness along the height of the concrete pylon is better,proving that the mechanical properties of the cable-pylon anchorage zone with unbonded prestressing steel bar system are better.
作者
杨万理
杨成发
李谏
幸荣邦
李昆星
YANG Wanli;YANG Chengfa;LI Jian;XING Rongbang;LI Kunxing(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;Aseismic Engineering Technology Key Laboratory of Sichuan Province,Chengdu 610031,China;Poly Changda Engineering Co.,Ltd.,Guangzhou,511431,China)
出处
《世界桥梁》
北大核心
2023年第4期63-69,共7页
World Bridges
基金
国家自然科学基金项目(51678491)
中央高校基本科研业务费专项项目(2682022ZTPY019)。
关键词
斜拉桥
索塔锚固区
预应力体系
无粘结预应力钢棒
力学特性
有限元法
cable-stayed bridge
cable-pylon anchorage zone
prestressing system
unbonded prestressing steel bar
mechanical property
finite element method
