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箱梁竖向预应力损失影响机理及控制措施研究

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混凝土箱梁桥腹板竖向预应力损失会造成腹板开裂.竖向预应力损失与施工工艺、机具、控制精度等因素有关.通过对预应力损失5个分项的计算分析,讨论各个分项对腹板竖向预应力损失的贡献值.采用有限元模型展开数值分析,研究了竖向预应力损失对箱梁各个部分的影响机理.得出以下结论:(1)对竖向预应力损失影响最大的是锚具变形和钢筋回缩损失,预应力筋与管道摩擦、混凝土弹性压缩、钢筋松弛、混凝土收缩徐变造成的竖向预应力损失较小;(2)在等截面箱梁中,梁高越小,竖向预应力损失对腹板的受力影响越大;在变截面箱梁中,竖向预应力损失对悬臂端部腹板受力影响较大,对悬臂根部影响较小;(3)竖向预应力控制的重点是优化张拉锚固机具,改进施工工艺.
Research on Influence Mechanism and Control Measures of Vertical Prestress on Box Girder
The loss of vertical prestress on webs of a concrete box girder bridge causes web cracking. The vertical prestress loss is related to the construction technology, machinery tools, control precision and other factors. Through the calculation and analysis of five items of prestress loss, the contribution value of each item to the vertical prestress loss of the webs was discussed. The influence mechanism of vertical prestress loss on each part of the box girder was studied by numerical analysis using the finite element model. The results are as follows: ① The most significant effect of vertical prestress loss is the loss of anchor deformation and reinforcement shrinkage, while the vertical prestress loss caused by the friction between prestressed tendons and pipes, elastic compression of concrete, reinforcement relaxation, shrinkage and creep of concrete is small;②In the vertical box girder with equal section, the smaller the beam height, the greater the effect of vertical prestress loss on the web stress; In the box girder with variable section, the effect of vertical prestress loss on the cantilever end web is greater than that on the cantilever root. ③ The emphasis of vertical prestressing control is to optimize tensioning anchorage machinery tools and improve the construction technology.

bridge websvertical prestressconcrete cracksprestress loss

丁渝、刘书丞、张庆明、吕国军

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重庆交通建设(集团)有限责任公司,重庆 401122

重庆路投科技有限公司,重庆 401147

桥梁腹板 竖向预应力 混凝土裂缝 预应力损失

重庆建工集团技术创新管理创新项目

2016020307

2024

重庆建筑
重庆市建筑科学研究院

重庆建筑

影响因子:0.292
ISSN:1671-9107
年,卷(期):2024.23(3)
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