摘 要

本桥为南通市沿江公路（如皋－通州段）的中心沙桥，设计上部结构形式为（3×20）m后张法预应力混凝土空心板梁桥，桥梁标准跨径为20m，桥面宽度：0.5m防撞护栏 11.25m车行道 2m中央护栏 11.25m车行道 0.5m防撞护栏=25.5m，桥面连续。下部结构采用桩柱式桥墩台配桩基础，两头设桥头搭板。

本计算书通过计算中心沙桥预应力混凝土空心板梁上部结构及其下部结构，进行上部结构设计时，标准跨径20m，并排布置24块空心板；预应力钢筋布置，采用 股钢绞线，公称直径d=15.2mm，应使其重心线不超过束界范围；采用后张法预应力空心板梁构造形式，首先根据结构在正常使用极限状态下正截面抗裂性要求确定预应力钢筋的数量，再由构件正截面承载能力极限状态要求确定普通钢筋的数量，然后进行承载力极限状态的验算，以及计算预应力钢筋损失，最后进行应力验算、抗裂性验算、变形计算等，确定构件满足承载力极限状态和正常使用极限状态下的各方面要求。进行下部结构设计时，桥墩采用柱墩，直径1.2m，桥台选用桩接盖梁桥台，基础选用钻孔灌注桩，直径为1.2m。结合上部结构荷载，桥墩立柱和桥台桩基按偏心受压计算，根据土层计算桩长；计算内力，设置钢筋并进行校核。

关键词：张拉法；空心板梁；应力损失；钻孔灌注桩

The Construction Drawing Design of

Center Sandy Bridge

ABSTRACT

This bridge is Center Sandy Bridge in NanTong riverside highway (rugao - tongzhou section) , the upper structure design form is (3 x 20) m method of post-tensioned prestressed concrete hollow slab bridge. The standard span is 20 m and the span bridge deck width is: 0.5 m crash barrier 2 m 11.25 m roadway central guardrail 0.5 m 11.25 m roadway crash barrier = 25.5 m. The deck is continuous. The lower structure is adopted by pile type bridge pier with pile foundation, and two head set bridge strap.

In this paper, the author designed and calculated upper pretressed concrete hollow sslabs structure and lower structure .In the upper structure design, the standard span is 20 m, When calculating the upper structure and lower structure,24 pieces of hollow slabs are set up side by side. The pretressed reinforcement is use of shared steel strand, and the nominal diaemter 15.2mm.Line should keep its center of gravity not beyond the scope of bundle boundary ; The construction of the hollow slab of the post-tensioned method is adopted. First of all, according to the structure in serviceability limit state of normal section crack resistance requirements determine the number of prestressed reinforcement, and by component of normal section bearing capacity limit state requirements to determine the number of ordinary reinforced, then calculating the bearing capacity limit state, and prestressed loss calculation, the stress calculation, crack resistance, calculation of deformation, etc., determining components to meet the various requirements of the bearing capacity limit state and serviceability limit state under the various aspects. The design of lower structure use column pier and the diameter is 1.2 m, choosing pile joint cover girder bridge abutment, foundation with bored piles, and the diameter 1.2 m .Combined with the upper structure load, the abutment pier column and pile foundation according to the eccentric compression calculation, according to the soil pile length to Calculate the internal force, set steel bar and checking.

Key word: Post-tension; Hollow slabs; Stress loss; Bored piles

目录

1设计资料 1

1.1主要技术指标 1

1.2 材料规格 1

1.3 采用的技术规范 1

2构造形式及尺寸选定 2

3空心板毛截面几何特性计算 3

3.1 毛截面面积A 3

3.3空心板毛截面对其重心轴的惯距 3

3.4空心板毛截面的抗扭刚度 3

3.2 毛截面重心位置 3

4作用效应计算 5

4.1永久作用效应计算 5

4.1.1空心板作用效应计算 5

4.2可变作用效应计算 6

4.2.1 汽车荷载横向分布系数计算 6

4.2.2 汽车荷载冲击系数计算 12

4.2.3 可变作用效应计算 13

4.3作用组合 17

5预应力钢筋数量的估算 20

5.1预应力钢筋数量的估算 20

5.2预应力钢筋的布置 21

5.3普通钢筋截面积估算及布置 22

6主截面几何特性计算 24

6.1换算截面面积 24

6.2换算截面重心位置 24

6.3换算截面惯矩 24

6.4截面抗弯模量 25

6.5预应力钢筋几何特性计算 25

7承载能力极限状态计算 27

7.1跨中截面正截面抗弯承载力计算 27

7.2斜截面抗剪承载力计算 28

7.2.1截面抗剪强度上下限复核 28

7.2.2截面抗弯承载力 30

8预应力损失计算 31

8.1预应力钢筋张拉控制应力 31

8.2预应力损失 31

8.21预应力钢筋与管道间摩擦引起的预应力损失 31

8.22锚固变形、钢筋回缩引起预应力损失 31

8.23预应力钢筋分批张拉时混凝土弹性收缩引起的应力损失 32

8.24钢筋松弛引起的预应力损失 33

8.25混凝土收缩、徐变引起的预应力损失 33

8.26预应力损失组合及有效应力 35

9应力验算 36

9.1短暂状况的正应力计算 36

9.2持久状况的正应力验算 36

9.21跨中截面混凝土正应力计算 36

9.22 持久状况下混凝土主应力验算 37

10抗裂性验算 41

10.1作用频遇组合下的正截面抗裂验算 41

10.2作用频遇组合下的斜截面抗裂验算 42

11主梁变形（挠度）计算 45

11.1荷载频遇组合作用下主梁挠度验算 45

11.2预加力引起的上拱值计算 45

11.3预拱度设置 46

12锚固区局部承压计算 47

12.1局部承压区尺寸要求 47

12.2局部抗压承载力计算 48

13下部结构设计 50

13.1 设计资料 50

13.1.1设计标准及上部构造 50

13.1.2材料规格 50

13.1.3设计依据 50

13.2 桥台盖梁计算 50

13.2.1荷载计算 50

13.2.2内力计算 58

13.2.3截面配筋设计与承载力校核 59

13.3桥墩盖梁计算 64

13.3.1荷载计算 64

13.3.2内力计算 72

13.3.3截面配筋设计与承载力校核 74

13.4桥台桩基计算 80

13.4.1荷载计算 80

13.4.2桩长计算 83

13.4.3桩的内力计算 84

13.4.4桩身配筋设计与承载力校核 85

13.4.5位移验算 87

13.5桥墩墩柱设计 88

13.5.1作用效用计算 88

13.5.2截面配筋设计及承载力校核 90

13.6桥墩桩基计算 92

13.6.1荷载计算 92

13.6.2桩长计算 93

13.6.3桩的内力计算 94

13.6.4桩身配筋设计与承载力校核 95

13.6.5位移验算 97

结 论 99

致 谢 100

参考文献 101

1设计资料

1.1主要技术指标

桥跨布置: 16×20.0 m，桥梁全长340 m；