四跨预应力混凝土连续梁桥设计

摘要.................................................................. II Abstract .............................................................. II 绪论. (1)

1上部结构设计概述 (3)

1.1设计基本资料 (3)

1.2 截面形式及截面尺寸拟定 (4)

1.3毛截面几何特性计算 (5)

2 上部结构内力计算 (9)

2.1 单元划分 (9)

2.2 恒载内力计算 (10)

2.3 温度及墩台基础沉降次内力计算 (11)

2.4 收缩次内力 (15)

2.5 活载组合内力计算 (16)

2.6 内力组合 (18)

3 预应力钢束的估算与布置 (24)

3.1 计算原理 (24)

3.2预应力钢束的估算 (27)

3.3 预应力钢束布置 (29)

3.4预应力损失计算 (32)

4 普通钢筋估算 (37)

5 强度验算 (39)

6 应力、变形验算 (41)

6.1基本原理 (41)

6.2施工阶段应力验算 (41)

6.3 使用阶段应力验算 (47)

6.4 挠度的计算与验算预拱度的设计 (57)

7 桥墩的计算 (60)

7.1 设计资料 (60)

7.2 墩柱计算 (61)

8 钻孔灌注桩计算 (65)

8.1 荷载计算 (65)

8.2 桩长计算 (66)

8.3 桩的内力计算（m法） (66)

8.4 桩顶纵向水平位移验算与桩身材料截面强度验算 (69)

结束语 (72)

致谢 (73)

参考文献 (74)

根据设计任务书要求和设计规范的规定，本着“安全、适用、经济、美观”八字原则，对平南高速公路D匝道桥第三联进行了设计。该桥上部为四跨预应力混凝土连续梁桥，均为30m。桥基础为二根桩单排布置。

第一章进行上部结构的计算。对30m跨径采用刚性铰接板法计算出跨中和1/4跨的荷载横向分布系数，支点的用杠杆法计算出。根据恒载和活载的两种组合进行了配筋，按新规范进行了预应力损失的计算，按短暂和持久状态进行了应力验算。并对30m跨径的用桥梁博士软件进行了配筋和应力验算。

第二章进行下部结构的计算，主要包括了盖梁和桩基础的计算。盖梁活载横向分布系数在荷载对称布置时采用杠杆法，非对称布置时采用偏心受压法进行计算。桩基础采用“m法”，墩柱采用偏心受压构件进行了计算。

然后进一步进行截面强度的验算，其中包括承载能力极限状态和正常使用极限状态。在正常使用极限状态验算中包括计算截面的混凝土法向应力验算、预应力钢筋中的拉应力验算、截面的主应力计算。

关键词: 预应力混凝土桩基础墩柱

Abstract

According to the specification requirements and general design code for bridges and culverts, and on the basis of the principle of the safety, utility，economy and aesthetics ，we have carried out the third unite located at the D ramp bridge of PINGNANP Highway. The bridge is structured with four spans of prestressed concrete continuous bridge, which are simply supported. The length of the four spans is all 30meters. The abutment adopts two piles single-rowly disposed.

The first chapter calculates the upper structure. The load lateral distribution coefficient between quarter span and mid span, is calculated with the law of the pin-joint method, and the pivot with the law of lever method. On the basis of two combinations of live loads and dead loads, prestressed cables are calculated. According to the new design code, the loss of the prestressed concrete has also been calculated, by temporary and lasting state. And the 30-meter span has been calculated with the application software—Doctor Bridge.

The second chapter calculates the substructure, including pier coping and piers. The calculation of lateral distribution coefficient of the pier coping adopts the law of lever method when loads are disposed symmetrically, the law of eccentric-compressing method when loads are disposed unsymmetrically. The calculation of the piles adopts the law of m-method. The piers are calculated as eccentric compression members.

The last step is checking the main cross section. the work includes the load-caring capacity ultimate state and the normal service ability ultimate state as well as the main section’s being out of shape.

Keywords: prestressed concrete pile pier