工科论文：路桥专业论文：桥梁设计论文[1]

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摘要：设计是根据设计任务书的要求和《公路桥规》的规定对胜利河桥进行方案比选和设计的。对该桥的设计，本着“安全、实用、经济、美观”的八字原则，本设计提出三种不同的桥型方案进行比较和选择。方案一为预应力混凝土连续梁桥，方案二为梁拱组合体系桥，方案三为悬索桥。经由以上原则以及设计施工等诸多方面考虑后，确定预应力混凝土连续梁桥为最终设计方案。

本预应力混凝土连续梁桥共分为三跨（30m+50m+30m）主跨50m，边跨对称30m；主梁采用单箱单室预应力混凝土箱梁，跨中梁高为1.5m，支座处梁高为2.8m，截面高度按二次抛物线形式变化；桥面净宽为7+2×1.5m；设计荷载为公路-Ⅰ级。

在设计中，运用了桥梁设计软件Midas建立桥梁模型，并对桥梁恒载、活载及徐变内力进行分析计算，得出预应力钢束的预估值。最后对主梁的应力、变形等进行验算。经分析比较及验算表明该设计计算方法正确，内力分布合理，符合设计任务的要求

关键词 桥梁设计; 预应力混凝土; 箱梁; 变截面连续梁 ;Midas桥梁模型

Abstract: The design is based on the requirements of the design task and "Highway Bridge Regulation". The design of the bridge is carried out in the eight-character principle of "safety, pratically, economically and aeshetic" by comparing and choosing the best one. The first program is continous prestressed concrete grider bridge, the second one the beam combination of arch bridge,and the third one is the suspension bridge.Accdoding to the above principles and construction factors, the prestressed conous bridge is chosen to the ultimate.
The continous prestressed concrete girder bridge is divided into three inters, (30m+50m+30m), with the main span of 50m, and 30m-symmetry one. Prestressed concrete box grider is used as the main beam; the beam depth in the mid-span is 1.5m, while at the support bearing it is 2.8m.The sectional depth is changed in the form of parabolic.The net width of the deck is 7+2x1.5m,and the design load is for the highway-I.
In the design, the bridge design software MIDAS is used to get the calculation model. By analyzing and computing the dead load, live load and internal force, the estimated value of the prestressed strand is got. Finally, checking calculation is carried out to the stress and deformation of the main beam. The results of the analysis and checking calculation show that the design calculation method is correct , and the internal force distribution is reasonable to the design task.
Key words: bridge design; prestressed concrete; box-girder; non-uniform continuo工学论文