兰州交通大学毕业设计

土木工程学院

桥梁工程

土木076班

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摘 要

本毕业设计的对象为一座10×30m简支梁桥，桥梁平面位于直线段上，全长300米，宽度10米，设计荷载为公路Ⅱ级。主梁横向由5片T梁组成，梁高均为1.5m，两片梁之间设置4cm宽现浇湿接缝。本桥采用桩柱式桥墩，直径1.5m的圆形截面墩柱及直径1.8m的圆形截面钻孔灌注桩，桩基础嵌入完整微风化砂岩5.4m以下；采用重力式U型桥台，桥台基础为直径1.5m的钻孔灌注桩基础。

桥梁上部结构手算进行主梁内力分析。横向分布系数通过桥梁博士3.0

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计算完成。内力计算结果包括基本组合、长期组合及短期组合作用下的弯矩图、剪力图、最大应力图。根据内力计算结果，对主梁进行了承载能力及正常使用性能的验算。盖梁承载能力验算及裂缝宽度验算与抗剪验算、墩柱承载力验算及裂缝宽度验算、桩基承载力验算及裂缝宽度验算均由自编计算机程序计算完成，墩柱与桩基的水平位移及其它效应由桥梁博士3.0计算完成。

根据验算结果得出结论：设计的桥梁结构是安全、经济、合理的，并满足现行规范的要求。

关键词：桥梁；荷载组合；内力；验算；承载能力

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Abstract

The object in this graduation project is a simply supported three-span girder bridge ( 10×30m) i. The bridge is straight on the plane with 300 metres in length and 10 meters in width.The bridge is a part of a highway which the design load is Highway-I-level. The main beam is made up of 5 T-beams that are 1.5m high and the adjacent beams are linked by pouring wet joint with 4cm in width between the two beams. Substructure is made up of circular section piers with a diameter of 1.5 and circular section bored pouring pile foundation with a diameter of 1.8 m, the pilings of foundation are embedded into the intack moderately differentiated rock with a depth of 5.4m. The concrete gravity abutment is 6.5m high with a type of U and supported by pile foundation. Analysis of superstructure in the bridge be done by hand. Simply supported single T-beam is used as analysis model in the program, only one edge beam is analysed and the mid beam using the same result in analyzing on safe side. Transverse distributing coefficient can be exported by using Dr bridge 3.0. The calculations include bending moment diagram, shear force diagram and maximum stress under basic/long-term/short-term load combination. According to the calculations, checking of capacity and performance of normal use of the beam have been done. Checking of capacity/crack width/shear strength of bent cap, capacity /crack width of piers and piles are done by Dr bridge 3.0.

According to the calculation results, the bridge designed in this graduation project was safe, economical and reasonable, and it is qualified for the present bridge design specifications .

Keywords:Bridge;Load combination; Inner Force; Capacity

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目录

第一章 设计说明 ............................................................................................................. 1 第一节 工程概况 ............................................................................................................. 1 第二节 设计依据及规范 .................................................................................................. 1 一、设计依据 ....................................................................................................................... 1 二、主要设计规范 ............................................................................................................... 1 第三节 地质概况 ............................................................................................................. 2 一、地形地貌 ....................................................................................................................... 2 二、地质构造 ....................................................................................................................... 2 三、地层岩性 ....................................................................................................................... 2 四、不良地质现象及主要工程地质问题 ........................................................................... 3 五、地震 ............................................................................................................................... 3 六、水文地质条件 ............................................................................................................... 4 第二章 设计计算 ............................................................................................................. 6 第一节 采用的技术标准及参数 ....................................................................................... 6 第二节 主要材料及计算参数 ........................................................................................... 6 一、混凝土 ........................................................................................................................... 6 二、普通钢筋 ....................................................................................................................... 7 三、预应力钢材 ................................................................................................................... 7 四、预应力锚具及管道 ....................................................................................................... 8 第三节 主要结构设计 ...................................................................................................... 8 第四节 主梁结构验算 ...................................................................................................... 9 一、计算模型与恒载取值 ................................................................................................... 9 二、主梁内力计算及验算 ................................................................................................. 11 （一）横向分布系数计算 ............................................................................................. 11 （二）选择控制截面 ..................................................................................................... 12 （三）计算结果（1号梁） .......................................................................................... 12 （四）主梁截面验算 ..................................................................................................... 17 （五）挠度验算 ............................................................................................................. 27 （六）支座承载力验算 ................................................................................................. 28 第五节 下部结构验算 .................................................................................................... 28

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