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1、预应力混凝土先简支后连续梁桥设计摘要本次设计是有关预应力混凝土连续箱梁桥设计，桥梁跨径35m+50m+35m，先简支后连续结构梁桥在高等级公路中得到了越来越多的使用，渐渐代替了原来单一的简支梁桥或连续梁桥，它兼顾了简支梁桥和连续梁桥两者的优点。而体系转化在先简支后连续梁桥施工中具有重要意义。箱梁吊装完成后，预制梁非连续端安装在永久支座上，连续端安装在临时支座上，此时墩顶永久支座暂不受力，由临时支座参与结构受力，支撑箱梁，每跨之间为简支体系，待体系转换完成后，形成整体的连续结构体系，再将临时支座拆除，使原来布置在墩顶中间的永久支座参与受力。 简支转连续体系转换的主要施工工序是先连接桥面板钢筋、端
2、横梁钢筋及浇筑端横梁混凝土，再逐次连接连续接头段及设置接头钢束波纹管并穿束、绑扎中横梁钢筋、浇筑连续接头段和与顶板钢束同长范围内的湿接缝，待混凝土达到设计强度要求后，进行墩顶钢束张拉及压浆，再由跨中向支点浇筑剩余部分的湿接缝，最后拆除临时支座，使梁支承在永久支座上，经支座转换形成连续梁体系。简支转连续梁桥体系形成的关键是结构从简支状态转换为连续状态，包括混凝土现浇段施工、顶板负弯矩预应力张拉和临时支座的拆除。其中连续端浇筑及张拉压浆顺序采用对称浇筑、对称张拉。本次毕业设计主梁采用等高度箱型截面，横向布置4片箱梁。设计车速100Km/h，3车道，桥梁总宽:0.5+33.8+0.5=12.4m。桥
3、轴线为直线，道路纵坡3%，横向坡度1.5%。设计荷载标准为公路级。由于计算过程中有较多的数据处理，如采用手算较为繁琐，且准确性得不到保证，因此采用计算机辅助设计。本次设计采用了AUTOCAD、桥梁博士、EXCEL电子表格等软件，通过本次毕业设计，大幅提升了自己对办公软件及桥梁设计软件使用能力。关键词：预应力混凝土连续梁桥 先简支后连续 桥梁博士The design of prestressed concrete continuous box girder bridge designAbstract The design of prestressed concrete continuous bo
4、x girder bridge design, bridge span 35m+50m+35m, simple supported continuous girder bridge structure in high grade highway obtained the more and more use, and gradually replaced the original single beam bridge and continuous beam bridge, which take into account the advantages of simply supported bea
5、m bridge and a continuous beam bridge. And the system transformation of the first simply supported continuous beam bridge construction has important significance. Box girder hoisting finished, the precast beam non continuous terminal installed on the permanent support, continuous terminal installati
6、on in the temporary support, at the pier top permanent support temporarily not by force, by the temporary support in the structure stress, supporting the box beam, each cross between simply supported system, until after the completion of the system transformation, the formation of the overall contin
7、uous structure system, then the demolition of temporary support, so that the original layout in the pier top in the middle of the permanentsupport participation by force. Simply supported continuous system switch of main construction procedure is to connect the bridge deck reinforcement, end beam re
8、inforced and pouring the end cross beam concrete, and then successively connected continuous joint and joint setting steel beam with corrugated pipe and wear beam, lashing steel beams, pouring continuous joint section and with steel roof beam with long range wet joint, to be met the requirements of
9、the design strength of concrete, the pier top steel beam tension and grouting, again by a cross in to the rest of the fulcrum pouring wet joint, finally removal of the temporary support, the excited in the permanent support, the support conversion to form a continuous beam system. Simply supported c
10、ontinuous beam bridge system formed the key is structure simple supported conversion into a continuous state, including the removal of concrete cast-in-place section construction, roof negative bending prestressed pull and temporary support. The continuous casting and tension grouting sequence of th
11、e slurry is symmetrical, symmetrical tension. This graduation design main girder uses the height box section, the transverse layout 4 box girder. Design speed 100Km/h, 3 lane, bridge total width: 0.5+3 x 3.8+0.5=12.4m. The bridge axis is linear, the longitudinal slope of the road is 3%, the transver
12、se gradient is 1.5%. Design load standard for highway grade 1. Because of the calculation process, there are many data processing, such as the use of manual is more complicated, and the accuracy is not guaranteed, so the use of computer-aided design. This design uses the software such as AUTOCAD, br
13、idge doctor, EXCEL electronic form, through this graduation design, greatly improved his ability to use office software and bridge design software.Keywords: prestressed concrete continuous girder bridge Simply supported continuous Doctor bridge第1章 桥型方案比选1.1 桥梁设计资料1.1.1 桥梁方案比选在桥梁方案比选环节中，应该遵循以下原则：适用性原
14、则经济性原则舒适与安全性原则先进性原则美观原则1.1.2 设计资料1、 设计荷载：公路I级 2、 设计车速：一级公路；100km/h3、 桥面净空：2x0.5+11.4=12.4m4、 通航等级：无通航要求。5、 纵坡：3%，横坡1.5%，人行道横坡1.0%。6、 温度影响：考虑竖向梯度温度效应；年平均升降温差20 度。7、 基础变位：中墩基础下沉1cm8、 收缩徐变天数：3650天9、工程及地质条件：另附图。1.1.3 材料规格1、桥面铺装层：9cm厚沥青混凝土2、梁体混凝土材料： C50 3、预应力钢筋、波纹管及锚具：纵向预应力钢束采用ASTMA416-99标准的270级直径j15.24m
15、（75.0）高强度低松弛钢绞线。抗拉标准值为1860MPa，张拉控制应力为1395MPa，抗拉强度设计值为1260MPa，公称面积139.0m2。竖向预应力钢筋采用25精轧螺纹粗钢筋。横向预应力钢束采用270级直径j15.24m（75.0）高强度低松弛钢绞线。4、普通钢筋：上、下部构造各部件的受力钢筋、架立筋及骨架钢筋采用HRB335钢筋(1232)；非受力筋采用R235钢筋(820)。5、墩身及承台： C20 号混凝土1.1.4 设计内容（1）方案比选、拟定主梁和桥墩基本尺寸；建立计算模型；进行单元和节点的划分。（2）施工方法描述（施工方案、施工顺序）（3）主要施工阶段的内力图（最大悬臂阶段、边跨合龙阶段、中跨合龙阶段、桥面 铺装阶段）（4）活载内力计算（跨中、支点等截面内力影响线及活载布置）（5）次内力计算（温度、预应力、支座沉降、徐变等）（6）内力组合（承载能力极限状态和正常使用极限状态内力包络图、内力组合表）（7）预应力钢束估算及布置（8）承载能力极限状态强度验算（9）正常使用极限状态应力验算（预应力损失、主要施工阶段和使用阶段应力验算）（10）变形验算与预拱度设置（11）桥墩（台）、桩基设计与验算1.2 桥梁方案初拟1.2.1 方案一：简支转连续分离式箱梁桥 预应力先简支后连续结构日前在高速公路桥梁工程中已经广泛使用。简支梁桥优点：结构简单，便于规模化施
