38m 66m 38m预应力混凝土变截面连续箱梁设计

论文总字数：42323字

摘 要

预应力混凝土连续梁桥广泛运用在了现今的公路工程之中，逐渐成为了现代公路的主要构成之一。 

考虑了结构设计理念：安全，经济，实用，美观，并且根据设计任务书和规范的要求，选择比较了各种不同的桥梁结构形式之后，考虑了场地条件、土质施工条件等因素，最后将预应力混凝土箱型梁桥作为最终的设计方案。 

本设计预应力混凝土连续梁桥的主桥部分共分为三跨38m 66m 38m，主跨66 m，边跨对称38 m，桥面宽度为0.5m（防撞护栏） 11.0m（行车道） 0.5m（防撞护栏），截面为单箱单室箱型截面，设计荷载为公路一级。 

本次设计运用了midas civil，这是一款专门设计桥梁的软件。借助midas civil对桥梁的上部结构进行模拟，采用悬臂施工法施工桥梁主梁部分，采用满堂支架法施工桥梁边跨现浇部分。通过分析计算桥梁自重和汽车荷载产生的内力，得出预应力筋的预估值，进一步计算预应力筋产生的预应力而引起的二次内力，逐步完善模型。最后，进行荷载组合在承载力极限状态和正常使用状态下，对桥梁进行截面验算和强度验算，从而判断设计模型是否足够合理安全，如果验算不满足就需要重新对预应力筋的数量和布置进行修改，直到满足验算要求，最后得出完整设计。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：Midas桥梁模型；psc设计；预应力；变截面箱梁桥

Abstract

Prestressed concrete continuous girder bridge is one of the main structural forms of modern highway, belonging to a kind of prestressed bridge. In today's highway engineering, the prestressed concrete bridge structure is widely used.

Taking into account the structural design concept: safe, economical, practical, beautiful, and according to the design task book and specification requirements, choosing to compare the various forms of bridge structure, through the land conditions, construction conditions and many other considerations,I determine the final design for the prestressed concrete box girder bridge.

The main bridge part of the prestressed concrete continuous girder bridge is divided into three sections: 38m 66m 38m, main span of 66 m, side span symmetrical 38 m, bridge width of 0.5m (crash barrier) 11.0m (carriageway) 0.5m (crash barrier). Section for the single-box single-chamber box section, the design load for the highway level.

This design uses the bridge design software Midas to design the upper structure of the simulated bridge, and the construction method is simulated by cantilever basket construction method. At the same time, the internal load of the bridge is calculated and analyzed, the predicted value of the prestressed steel beam is obtained,and further calculate the secondary internal force of the pre-welded steel beam, perfect the model. Finally, in the ultimate bearing capacity and normal use of the state,I detailed finite element analysis. The results are compared with the requirements of the specification to check whether the internal force and deformation of the main beam meet the requirements, to determine whether the design model is reasonable and safe. Finally, a complete design is made out. The comparison and calculation shows that the design calculation method is correct, Internal force distribution is reasonable, in line with the design task requirements.

Key words: Midas bridge model; psc design; prestressed; variable cross section box girder bridge

目 录

第一章 绪论 7

1.1预应力混凝土连续梁桥概述 7

1.1.1 预应力混凝土连续梁桥发展 7

1.1.2 设计特征 7

1.1.3 受力特点 8

1.1.4 构造特点 8

1.1.5 连续梁的主要优点 9

1.2 方案比选.....................................................9

第二章 设计资料 11

2.1 设计标准....................................................11

2.2 场地条件 12

2.3 主要材料....................................................12

2.4 结构计算参数................................................14

第三章 桥梁总布置 14

3.1 桥梁平面布置................................................14

3.2 桥梁断面设计................................................15

3.3 桥梁桥型布置................................................16

3.4截面尺寸 16

3.5 桥梁下部结构................................................17

3.6 桥梁主梁段划分..............................................17

第四章 主桥施工流程及注意要点 19

4.1施工流程.................................................... 19

4.2 施工概略流程图..............................................20

4.3 施工要点....................................................22

4.3.1 主桥上部施工..........................................22

4.3.2 支座及桥面系构造......................................24

4.4 混凝土总用量................................................25

4.4.1 主梁混凝土用量........................................25

4.4.2 桥面铺装混凝土用量....................................26

4.5 钢绞线及锚具总用量..........................................26

第五章 midas模型 28

5.1 建模简介....................................................28

5.2 结构组、荷载组、边界组........................................34

5.2.1 结构组................................................34

5.2.2 荷载组................................................35

5.2.3 边界组................................................37

5.3 施工阶段....................................................37

5.3.1 0号块.................................................37

5.3.2 悬臂浇注阶段..........................................37

5.3.3 边跨合龙阶段..........................................38

5.3.4 中跨合龙阶段..........................................38

5.4 荷载工况....................................................38

5.5 静力荷载计算................................................39

5.6 静力荷载内力计算............................................43

5.7 活载内力计算................................................45

5.7.1 汽车荷载计算........................................45

5.7.2 汽车冲击力计算......................................45

第六章 桥梁配筋计算 45

6.1预应力筋束的布置原则 45

6.2 预应力筋数量估算 47

6.2.1 承载能力极限状态的应力要求 47

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