摘 要

预应力混凝土空心板在我国桥梁建筑上占有重要的地位，在目前，对于中小跨径的永久性桥梁，都在尽量采用预应力混凝土空心板桥，因为这种桥梁具有就地取材，工业化施工，耐久性好，适应性强，整体性好的优点。从而决定了本设计中桥型的选择，整个的计算方法。

本文对一个桥面宽为（0.75m护栏 11m行车道 2m中分带 11m行车道 0.75m护栏）的3×20米后张法预应力混凝土空心板简支桥进行了设计验算。文章拟定了桥梁的上部结构和下部结构尺寸，对荷载内力进行了计算，并且对主要构件进行了强度承载能力极限状态和正常使用极限状态验算。设计过程如下：

上部结构：首先，确定中板和边板的截面尺寸为宽99cm,高95cm，桥梁横断面由12块空心板组成。然后再通过铰接板法和杠杆原理法计算荷载的横向分布系数，并按照横向分布系数来计算每块板所承受的活载和永久荷载的量值。最后取每块板所受荷载的最不利荷载来进行空心板截面的预应力筋和非预应力筋的配置以及各类预应力损失大小的计算，并进行相应的应力验算和变形验算。

下部结构：下部结构的设计主要包括对盖梁和墩柱尺寸的拟定、荷载的计算、配筋的计算及承载力验算；然后选择桩基的持力层和埋置深度并用m法计算桩基的内力和位移。

计算表明，各项验算符合要求，设计方案合理。

关键词：预应力；空心板；设计；计算

Construction Drawing Design of Zhongshan Road Bridge

ABSTRACT

Prestressed concrete hollow slabs play an important role in the construction of bridges in China. At present, prestressed concrete hollow slab bridges are used for permanent bridges with small and medium spans because they have local materials and industrial construction. Good durability, strong adaptability, good integrity. Which determines the choice of the bridge type in this design, the entire calculation method.

In this paper, a 3×20 m post-tensioned prestressed concrete hollow slab simply-supported bridge with bridge width (0.75m fence 11m carriageway 2m center belt 11m carriageway 0.75m fence) was designed and checked. The upper and lower structural dimensions of the bridge are formulated, the internal forces of the load are calculated, and the main components are checked for the ultimate state of strength carrying capacity and the normal service limit state. The design process is as follows:

Superstructure: First, the cross-sectional dimensions of the middle plate and the side plate are determined to be 99 cm in width and 95 cm in height, and the cross-section of the bridge consists of 12 hollow plates. Then, the lateral distribution coefficient of the load is calculated by the hinge plate method and the lever principle method, and the magnitude of the live load and the permanent load that each plate bears is calculated according to the lateral distribution coefficient. Finally, take the most unfavorable load of each plate to carry out the configuration of prestressed tendons and non-prestressed tendons of the hollow slab section, and calculate the magnitude of various prestress losses, and perform corresponding stress checking and deformation checking.

Substructure: The design of the substructure mainly includes the drafting of cap beams and piers, the calculation of loads, the calculation of reinforcements, and the calculation of bearing capacity. Then, the bearing layer and depth of piles are selected and the pile foundation is calculated by m method. Internal forces and displacements.

The calculations show that each calculation meets the requirements and the design scheme is reasonable.

Key words：Prestressed；hollow board；design；calculation

目 录

1设计资料 - 1 -

1.1跨度和桥面宽度 - 1 -

1.2技术标准 - 1 -

1.3主要材料 - 1 -

1.4设计要点 - 1 -

2横断面布置 - 2 -

2.1横断面布置图 - 2 -

2.2预制板截面尺寸 - 2 -

3汽车荷载横向分布系数、冲击系数 - 3 -

3.1汽车横向分布系数计算 - 3 -

3.1.1跨中横向分布系数 - 3 -

3.1.2支点横向分布系数 - 5 -

3.1.3车道折减系数 - 5 -

3.2汽车荷载冲击系数的计算 - 6 -

4作用效应组合 - 7 -

4.1作用的标准值 - 7 -

4.1.1永久作用的标准值 - 7 -

4.1.2汽车荷载作用的标准值 - 8 -

4.2作用效应组合 - 9 -

4.2.1基本组合 - 9 -

4.2.2频遇组合和准永久效应组合 - 11 -

5钢筋面积的估算及钢束布置 - 12 -

5.1预应力钢筋截面积估算 - 12 -

5.2预应力钢筋的布置 - 12 -

5.3非预应力筋的估算 - 14 -

6主梁截面几何特性的计算 - 15 -

6.1中板截面几何特性 - 15 -

6.1.1第一阶段 - 15 -

6.1.2第二阶段 - 16 -

6.2边板几何特性 - 17 -

6.2.1第一阶段 - 17 -

6.2.2第二阶段 - 19 -

7持久状况截面承载能力极限状态计算 - 21 -

7.1正截面承载力计算 - 21 -

7.2斜截面承载能力计算 - 21 -

8预应力损失估算 - 23 -

8.1力筋与管道壁间摩擦引起的应力损失 - 23 -

8.2锚具变形、钢丝回缩引起的应力损失 - 23 -

8.3分批张拉时混凝土弹性压缩引起的应力损失 - 24 -

8.4钢筋松弛引起的预应力损失 - 25 -

8.5混凝土收缩、徐变引起的预应力损失 - 26 -

9应力验算 - 29 -

9.1短暂状况应力验算 - 29 -

9.2持久状况的应力验算 - 29 -

10抗裂性验算 - 36 -

10.1作用短期效应组合作用下的正截面抗裂验算 - 36 -

10.2作用短期效应组合作用下的斜截面抗裂验算 - 37 -

11主梁变形计算 - 41 -

11.1荷载短期效应作用下主梁挠度验算 - 41 -

11.2预加力引起的上拱度计算 - 41 -

11.3预拱度的设置 - 42 -

12锚固区局部承压的计算 - 43 -

12.1局部受压区尺寸要求 - 43 -

12.2局部抗压承载力计算 - 44 -

13支座设计 - 45 -

13.1选定支座的平面尺寸 - 45 -

13.2确定支座的厚度 - 45 -

13.3验算支座的偏转 - 46 -

13.4验算支座的稳定性 - 46 -

14桥梁下部结构的计算 - 48 -

14.1盖梁计算 - 48 -

14.1.1盖梁尺寸的拟定 - 48 -

14.1.2盖梁的自重及作用效应的计算 - 48 -

14.1.3可变荷载的计算 - 49 -

14.1.4内力计算 - 53 -

14.1.5截面配筋设计和承载力校核 - 56 -

14.2墩柱计算 - 60 -

14.2.1作用计算 - 60 -

14.2.2截面配筋计算 - 61 -

14.3桩的设计计算 - 62 -

14.3.1桩长的确定 - 62 -