西安潏河简支桥梁上部结构设计

时间：2021-04-14 20:05:15 来源：蒲公英阅读网 本文已影响人

相关热词搜索：西安 结构设计 桥梁

　摘 要 桥梁在设计过程中，上部结构（桥跨结构和支座系统）设计的合理性，影响整座桥梁的安全性、耐久性。通过一系列数据分析，对桥梁上部结构的一系列方案进行对比，选出最佳的上部结构设计方案，以达到满足交通需求、安全性且尽可能降低成本的目的。

　T 型截面桥梁两肋处的混凝土很大程度上被挖空，桥体自重大幅减轻。混凝土本身抗压能力远远大于其抗拉能力，因此下部受拉钢筋提供了抗拉部分的绝大部分拉力，下部钢筋的受拉作用得到了充分地发挥。所以预应力 T 型梁混凝土用量少，桥体自重小，上部的压力又混凝土来承担，下部的拉力由预应力钢筋来承担，结构和受理性因此能都能达到理想的状态。由于其混凝土简支 T 梁桥有构造简单、施工方便、受力明确，能充分发挥材料特性等特点，已经成为了中小跨桥梁形式的首选方案。预应力混凝土 T 形梁是一种简支 T 形梁桥结构，具有构造简单，造价低廉，具有较好的跨越能力现在被越来越多的中型、大型桥梁桥梁作为首选方案，而且因为其便于维护，也成为了国防建设的首选桥梁。

　关键词：

　：简支梁桥；预应力；方案比选；有限元模型。

　ABSTRACT The rationality of superstructure （bridge span structure and support system）

　design affects the safety and durability of the whole bridge in the process of bridge design. A series of schemes of bridge superstructure are compared, whilst the best superstructure design scheme is selected to meet the traffic demand, safety and economy through a series of data analysis. The concrete at the two ribs of T-section bridge is largely hollowed out, so the self weight of the bridge body is greatly reduced. The compressive capacity of concrete itself is far greater than its tensile capacity, so the tensile force of the tensile part is provided by the lower tensile reinforcement. Therefore, the amount of concrete used in prestressed T-beam is small, the weight of bridge body is small too. The upper pressure is borne by concrete, and the lower tension is borne by prestressed steel, so the structure and acceptability can reach the ideal state. The concrete simply supported T-section bridge has become the preferred option for medium and small span bridges, because of its simple structure, convenient construction, clear force and full use of material characteristics. T-beam bridge structure include prestressed concrete T-beam, which has good spanning ability, simple structure and low cost. Now, more and more medium-sized and large bridges are the first choice. Because it is easy to maintain, prestressed concrete T-beam has also become the first choice for national defense construction.

　 Keywords: Finite element model; Simply supported beam bridge; Prestressed; Scheme comparison.

　 I

　目 录 摘 要

　ABSTRACT

　目 录................................................................................................................ - 1 -

　1 基本资料...................................................................................................... - 1 -

　1.1 地质条件........................................................................................... - 1 -

　1.2 水文条件........................................................................................... - 1 -

　1.3 气象条件........................................................................................... - 1 -

　1.4 工程意义........................................................................................... - 2 -

　2 方案设计...................................................................................................... - 2 -

　2.1 方案比选........................................................................................... - 2 -

　2.2 设计资料........................................................................................... - 3 -

　2.3 基本计算数据.................................................................................... - 3 -

　3 尺寸设计...................................................................................................... - 5 -

　3.1 主梁尺寸........................................................................................... - 5 -

　3.2 截面的几何特性............................................................................... - 5 -

　3.2.1 跨中截面................................................................................ - 5 -

　3.2.2 支座截面................................................................................ - 7 -

　3.2.3 检验跨中截面效率指标 ρ...................................................... - 7 -

　3.3 预应力施加阶段的截面几何特性................................................... - 8 -

　3.3.1 跨中截面................................................................................ - 8 -

　3.3.2 支座截面................................................................................ - 8 -

　3.3.3 检验跨中截面效率指标 ρ...................................................... - 9 -

　4 主梁内力计算.............................................................................................. - 9 -

　4.1 永久作用效应计算........................................................................... - 9 -

　4.1.1 永久作用集度........................................................................ - 9 -

　4.1.2 永久作用效应...................................................................... - 11 -

　4.2 可变作用效应计算（G-M 法）

　.................................................... - 12 -

　4.2.1 冲击系数和车道折减系数.................................................. - 12 -

　4.2.2 主梁的荷载横向分布系数................................................... - 12 -

　 II

　4.2.3 车道荷载取值...................................................................... - 19 -

　4.2.4 计算可变作用效应.............................................................. - 19 -

　4.3 主梁作用效应组合......................................................................... - 22 -

　5 钢筋面积的估算及钢束布置.................................................................... - 25 -

　5.1 预应力钢筋..................................................................................... - 25 -

　5.1.1 面积计算.............................................................................. - 25 -

　5.1.2 确定束界.............................................................................. - 25 -

　5.1.3 预应力筋布置：.................................................................. - 27 -

　5.2 非预应力钢筋................................................................................. - 29 -

　5.2.1 面积计算.............................................................................. - 29 -

　5.2.2 非预应力筋布置.................................................................. - 29 -

　6 锚固区局部承压计算................................................................................ - 29 -

　6.1 锚具................................................................................................. - 29 -

　6.2 局部受压区尺寸要求............................................ 错误! 未定义书签。

　6.3 局部抗压承载力计算..................................................................... - 30 -

　7 主梁截面几何特性计算............................................................................ - 31 -

　7.1 第Ⅰ阶段截面几何特性................................................................. - 31 -

　7.2 第Ⅱ阶段截面几何特性................................................................. - 33 -

　7.2 第Ⅲ阶段截面几何特性................................................................. - 35 -

　8 持久状况截面承载能力极限状态计算.................................................... - 37 -

　8.1 跨中截面正截面承载力计算......................................................... - 37 -

　8.2 斜截面抗剪承载力计算................................................................. - 38 -

　8.2.1 距支点 h/2=800mm 处截面：

　............................................ - 38 -

　8.2.2 变截面处............................................................................... - 39 -

　8.2.3 L/4 截面处 ............................................................................ - 40 -

　8.2.4 跨中截面.............................................................................. - 41 -

　8.3 斜截面抗弯承载力计算.................................................................. - 41 -

　9 钢束预应力损失估算................................................................................ - 42 -

　9.1 预应力钢束与管道壁之间的摩擦引起的预应力损失1 l

　........... - 42 -

　9.2 由锚具变形、钢束回缩引起的预应力损失2 l

　........................... - 44 -

　 III

　9.3 预应力钢筋分批张拉时混凝土弹性压缩引起的应力损失4 l

　... - 44 -

　9.4 钢筋松弛引起的的预应力损失 5 l ............................................... - 45 -

　9.5 混凝土收缩、徐变引起的损失 6 l............................................... - 45 -

　10 应力验算.................................................................................................. - 48 -

　10.1 短暂状况的正应力验算............................................................... - 48 -

　10.2 持久状况下的正应力验算........................................................... - 49 -

　10.2.1 截面混凝土正应力验算.................................................... - 49 -

　10.2.2 持久状况下预应力钢筋的应力验算................................ - 49 -

　10.2.3 持久状态下混凝土主应力验算........................................ - 50 -

　11 抗裂性验算 .............................................................................................. - 52 -

　11.1 短期效应组合作用下正截面抗裂验算 ........................................ - 52 -

　11.2 作用短期效应作用下的斜截面抗裂验算 ................................... - 53 -

　11.2.1 主应力计算 ........................................................................ - 53 -

　11.2.2 主拉应力的限制值 ............................................................ - 54 -

　12 主梁变形（挠度）计算.......................................................................... - 55 -

　12.1 荷载短期效应作用下主梁挠度计算........................................... - 55 -

　12.1.1 可变荷载作用引起的挠度................................................ - 55 -

　12.1.2 在长期效应下引起的挠度................................................. - 55 -

　12.2 预加力引起的上拱值计算........................................................... - 55 -

　12.3 预拱度的设置............................................................................... - 56 -

　13 行车道板的计算...................................................................................... - 56...