摘要
一些钢管混凝土拱桥运营后,拱脚处钢管外包混凝土出现了明显可见过宽的裂缝,影响结构的使用与耐久性,但相关规范未对外包混凝土设计提出要求.本文以某下承式钢管混凝土系杆拱桥为工程背景,运用Midas/Civil建立全桥模型并提取拱肋截断面最不利内力组合,再运用ANSYS建立拱脚局部模型,分析钢管与外包混凝土界面、拱肋截断面各内力分量对拱肋附近外包混凝土应力的影响,研究拱肋附近外包混凝土应力随外包混凝土厚度增大的变化规律.计算结果表明,拱脚裂缝主要由拱肋轴力引起,钢管受压膨胀挤压外包混凝土使其产生拉力,加大钢管外包混凝土厚度能有效减小拉应力.通过多工况的计算给出了满足抗裂限裂要求的最小外包混凝土厚度.
In the service period of concrete-filled steel tube arch bridges, there is a problem that the cracks of the surrounding concrete of the steel pipe at arch foot are too wide, which is not referenced in the relevant specifications. Taking a through concrete-filled steel tube tied arch bridge as the engineering background, a full-bridge model is established by using Midas / Civil and the most unfavorable internal force combination in the sections of arch ribs is found out. Then, the local model of arch foot is established by ANSYS. The influ- ence of the interface between steel pipe and the surrounding concrete on the stress of the surrounding concrete near the arch ribs is analyzed. The influence of the internal force component of the arch rib sections on the stress of concrete is also analyzed; and then the variation law of the stress of surrounding concrete near the arch ribs with the thickness of the surrounding concrete is studied. The calculation results show that the crack of the arch foot is mainly caused by the axial force of the arch rib. The lateral expansion of steel pipe caused by axial compressive force compresses the surrounding concrete to produce the tensile force; and the increase of the thickness of surrounding concrete can reduce the tensile force effectively. Finally, the minimum thick- ness of the surrounding concrete which can meets the requirements of crack resistance or crack control is given via the calculation of several conditions.
出处
《三峡大学学报（自然科学版）》
CAS
北大核心
2018年第1期48-53,共6页
Journal of China Three Gorges University：Natural Sciences
基金
国家自然科学基金项目(51678218)
江苏省优秀青年基金(8K20170097)
江苏省交通科学研究计划项目(2013y09)
关键词
钢管混凝土拱桥
拱脚裂缝
外包混凝土厚度
有限元
应力分析
concrete-filled steel tube arch bridge
crack of arch foot
thickness of surrounding concrete
finite elements
stress analysis
