摘要:钢管混凝土拱桥由于具有承载力高、塑性和韧性好、施工方便、经济效果好和地基适应性强等优点，是发展前景广阔的一种组合桥梁结构。目前钢管混凝土拱桥在我国已经历了十余年的发展，无论是其应用规模还是跨径增长的速度都是惊人的。相对而言我国建设钢管混凝士拱桥的技术已经达到国际先进水平，我国对钢管混凝十拱桥的理论研究也取得了很多成果。50045

本设计根据任务书要求设计一座三跨组合拱桥,经过严格的方案比选从三个备选方案中选择中承式钢管混凝土系杆拱桥作为设计方案。桥梁上部结构主要有主拱肋、横向支撑、吊杆、纵梁、横系梁及立柱等。中承式钢管混凝土拱桥美观且受力合理, 但该种桥型设计参数较多, 各参数相互关联, 给设计工作带来了困难。

首先进行初步设计，即拟定所选方案桥型的具体尺寸以及相关参数。主拱拱肋计算跨径80m，计算矢高20m，矢跨比1/4。最重要的是主拱肋的截面尺寸，都是根据根据规范和相关的参考资料来拟定。第二步就要进行结构计算，这其中最为关键的便是建模，最后的计算是否正确，在很大程度上取决于模型建得是否正确。本设计利用MIDAS软件，可计算出结构各控制截面的内力。

完成上述工作后，便要进行结构验算，对于拱桥最重要的就是要验算拱圈截面承载力与拱圈的整体稳定性。建模完成后便进行运行分析，可在“结果”菜单内查看荷载组合。荷载组合有基本组合、短期组合和长期组合等。对下面的验算来说，若进行承载能力验算，则选用强度包络下的组合；若进行正常使用验算，则选用应力包络下的组合；若进行挠度验算，则选用位移包络下的组合。

对于施工方法，本桥采用的是拼装法施工拱肋，满堂支架施工上部结构。适合平坦的河滩施工。但不足之处是拱肋在空中对接精度较难控制，拱轴线型控制有一定的难度，分段越多，其工期和质量控制的难度就越大，施工费用也越高，在施工中要采用新技术和新工艺。灌注钢管内混凝土采用泵送顶升法。

通过本次设计来总结大学中的学习成果，并对未来的发展作了简要的展望。本文在最后附加了CAD图纸用以对整个结构的尺寸、平立剖面、钢束布置形状作进一步的说明与补充。

毕业论文关键词： 组合拱桥；中承式；钢管混凝土；系杆；结构分析

Design of a three - span combination arch bridge across the river in Jiaxing

Abstract: Half-through concrete tied arch bridge is a bridge-type, because of their trial, economic and other aesthetic aspects of the unique advantages, in recent years in the field of engineering are more widely used, because of the inherent characteristics of the structure to enable it to effective bridge to overcome common diseases are highly promotional value.

This design according to the specification requirements to design a three-span composite arch bridge, after rigorous project selection from the three options for the selection of concrete-filled steel tube-tied arch bridge as a design. Mainly in the upper part of the structure of the bridge the main arch, side arch, oblique lateral support and the support, boom, tie beam, horizontal line, beams and columns and so on. Half-through concrete arch bridge, beautiful and stress is reasonable, but the bridge design parameters, the parameters are related to design work, brings difficulties.

First, starting preliminary design, namely the elaboration of the selected programmers bridge the specific size and the relevant parameters. The arch ribs’ main hole calculation span is 100 m, calculated vector high is 25 m, rise-span ratio is 1/4. Ultimately to the arch bridge is the main section size, are in accordance with the norms and relevant reference materials to develop. 省道云和县城过境段公路工程计算书+CAD图纸:http://www.youerw.com/gongcheng/lunwen_53242.html