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| 预应力混凝土桥梁弯曲孔道接触应力研究 |
| Research on Contact Stress of Prestressed Concrete Bridge in Curved Duct |
| 投稿时间：2019-05-29 修订日期：2019-06-22 |
| DOI： |
| 中文关键词: 大跨度预应力混凝土桥梁 预应力损失 Hertz接触理论 弯曲孔道 接触应力 |
| 英文关键词: long span prestressed concrete bridges prestress loss Hertz theory curved duct contact stress |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| 中文摘要: |
| 大跨度预应力混凝土桥梁运营过程中,箱梁下挠与腹板开裂现象十分普遍。从结构受力分析,混凝土箱梁徐变效应所带来的跨中下挠,客观上表明梁体处于拉应力状态,与结构设计意图大相径庭,意味着预应力混凝土结构设计理论尚存在某些弊端。事实上,预应力摩阻损失依赖于钢束与弯曲孔道接触正应力分布。该文基于Hertz接触理论,通过一组预应力弯曲孔道模型挤压试验,借助CT扫描技术获取试验模型的形变数据,并结合有限元分析软件ANSYS进行数值模拟,结果表明其接触应力分布呈钟型状；同时,探讨了孔道接触角、曲率半径、张拉力、摩擦系数等因素对预应力混凝土弯曲孔道接触应力的影响。研究结论对预应力混凝土构件设计理论的修正具有重要的理论指导意义。 |
| 英文摘要: |
| The phenomenon of mid-span deflection and web cracking of box girder of long span prestressed concrete bridges in operation is very common. According to the analysis of structural stress, the mid-span deflection, caused by creep effect of concrete box girder, indicates that the beam presents a tensile stress, which is quite different from the structural design intention, meaning that several drawbacks are needed to be considered in the design theory of prestressed concrete structures. In fact, the prestress loss, caused by frictional resistance, depends on the normal stress distribution of contact between prestressing beam and curved duct. In this paper, extrusion tests on a group of prestressed curved duct model were conducted, in which the deformation data of model were recorded using CT scanning technology. Meanwhile, Hertz contact theory and finite element software ANSYS were also adopted to further explore the contact stress in curved duct, and results suggest that the distribution of contact stress is bell-shaped. Furthermore, the effects of parameters including duct contact angle, curvature radius, tension force and friction coefficient on contact stress of prestressed curved duct were discussed. The conclusions in this paper, therefore, are of significant reference for revising the design theory of prestressed concrete structures. |
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