4×30m先简支后连续连续箱梁毕设

摘要

预应力混凝土连续箱梁桥优点很多，比如构造过程中整体刚度较大，动力性能良好，施工过程中工期较短，同时主梁挠曲变形相对较小，这样对行车速度要求较高，通常适用于高速公路。另外，就先简支后转连续施工方法而言，由于其成桥后，在支点会产生负弯矩，对跨中的正弯矩进行了平衡，从而提高了桥梁整体稳定性与耐久性，比普通的简支梁桥受理更均匀更合理。目前在大多高速公路桥中应用极其广泛。

本设计主梁采用预应力混凝土连续箱梁，对主桥4×30 m连续箱梁进行了基本的设计。拟建该大桥正跨马跑沟河，为“U”字形河谷，工程地质分区属于冲洪积平原地质区，桥址区域位于管子沟河道及两岸，河道两岸地势较为开阔，地形较为平坦，河道沟道较深。本设计一开始先对桥址资料包括水文、地质、气象进行描述，同时查阅了其适用的设计技术标准以及材料的选取，随即确定了设计方案及施工方法。结构设计过程大致如下：截面尺寸的拟定，每跨各个控制截面的内力及其各类组合的计算汇总，估束及布筋（预应力钢筋），对承载能力极限状态进行承载能力验算，对正常使用极限状态进行构件抗裂性及变形验算，对持久状况和短暂状况进行构件截面应力验算等。其中，钢束布置时，由于使用的是Midas软件建模，故一片中梁边跨共设36根s 15.2钢绞线，即N1每束设5根，N2、N3、N4每束均设4根，且N1、N2、N3、N4均设为2束；中跨跨中共设32根钢绞线，即N1、N2、N3、N4每束均设5根，且N1、N2、N3、N4均设为2束；中支点共设52根钢绞线，即T1、T3每束均设4根，T2每束设3根，且T1、T2设为2束，T3设为3束。验算后得知，主梁设计结构安全，并满足公路桥梁规范的各项要求。

关键词：预应力；连续箱梁；先简支后转连续

Abstract

Prestressed concrete continuous box girder bridges has many advantages, such as greater overall stiffness during construction, good dynamic performance, the construction process shorter duration, while the main beam deflection is relatively small, so the higher speed of traffic requirements, generally applicable on the highway.In addition, on the simply supported - continuous construction method, since it a bridge, at the fulcrum will produce negative moment, cross the positive moment was balance, thereby improving the overall stability and durability of the bridge, Charpy than ordinary bridge accept more uniform and reasonable. Currently the most telling highway bridge in applications is extremely broad. The design of the main beams of prestressed concrete box girder, the main bridge 4 × 30 m continuous box girder made the basic design.The proposed bridge being Kuama ditch run for the "U" shaped valley, engineering geological zoning belong to the alluvial plain of the geological area, the bridge site area is located on the river and on both sides of the pipe ditch, river sides more open terrain, the terrain is relatively flat, river deeper channel.The design of a bridge began on the first site information, including hydrology, geology, meteorology description, check the design of its applicable technical standards and the selection of materials, then determine the design and construction methods.Structural design process is as follows: a cross-sectional size of the formulation, calculated across a broad cross-section of the internal forces to control its various combinations of each summary, estimates and fabric reinforcement beam (prestressing steel), for the ultimate limit state checking the bearing capacity of normal limit state member crack resistance and deformation analysis of the situation and short lasting section stress member status checking and so on.Wherein, when the steel beam arrangement, as is the Midas software modeling, it is a center sill side span a total of 36 15.2 strand, which is located 5 per tow N1, N2, N3, N4 are located four per bundle, and N1, N2, N3, N4 are set to 2 bundle; cross cross Party set up 32 strands, namely N1, N2, N3, N4 are located 5 per bundle, and N1, N2, N3, N4 are set 2 bundle; fulcrum total of 52 strands, namely T1, T3 are located four per bundle, T2 located 3 per bundle, and T1, T2 to 2 beams, T3 is set to 3 bundles.After checking that the main design of the structural safety of