客运专线预应力混凝土毕业设计.doc

摘 要 随着经济、技术实力的增进，预应力混凝土连续梁桥已成为现代公路、铁路桥梁的首选，本设计为一客运专线预应力混凝土连续梁桥设计，预应力混凝土连续梁的应用，尤其是悬臂施工法的应用非常广泛，使施工设备机械化，生产工厂化，从而提高了施工质量，降低了施工费用。连续梁的突出优点是：结构刚度大，变形小，动力性能好，主梁变形挠曲线平缓，有利于高速行车。然而受时间等因素的限制，此次设计只涉及桥梁上部结构。 设计流程如下： 首先，确定主梁的主要构造和细部尺寸。考虑到抗弯刚度及抗扭刚度的需要，采用箱形截面梁。主梁的高度变化曲线采用二次抛物线。该设计为53+75+53客运专线预应力混凝土连续梁桥设计，其主跨75，边跨53，全桥采用单箱单室箱形梁，桥宽12，中支座梁高5,中跨跨中梁高2.5。主梁采用悬臂挂篮施工，主梁0#块和边跨现浇均采用满堂支架施工。 其次，根据悬臂施工挂篮的起吊能力对主梁进行施工节段的划分。 再之，利用MIDAS软件分析结构的内力（包括恒载和活载的内力计算）。用于计算的内力组合结果、混凝土毛截面特征值也由MIDAS软件自动生成，从而估算出纵向预应力筋的数目，然后在截面上布置预应力钢束。 次之，计算预应力损失及各项次内力，并进行了截面的强度验算（包括承载能力极限状态和正常使用极限状态）。 最后，绘制工程图及编制说明书。 注明：本设计未考虑风荷载、地震以及结构动力特性等因素。 关键词：客运专线；悬臂施工；满堂支架；箱形截面 Abstract With the promotion of economic and technological strength, prestressed concrete continuous girder bridge has become the first choice of modern highway and railway bridges .The design is about a passenger line design of prestressed concrete continuous girder bridge，The application of continuous prestressed concrete beams, in particular cantilever construction method’s widely used , makes construction equipment mechanization, factory, thereby enhances the quality of construction and reduces construction costs. The highlight advantages of continuous beams are: structural rigidity, low distortion, good dynamic performance, the main beams deflection gentle, beneficial to high-speed traffic. But in the short time, this design involves only the bridge superstructure. The procedure of the design is listed as follows: First, design the main structural elements and detail sizes. At the same time, considering the distorting stiffness and the bending stiffness, the girder is used the box section. The box girder shapes likes a second-parabolic curve, for second-parabolic curve is generally similar to the change of continuous rigid frame bridge’s bending moments. The thickness of the bottom slab is changed in linearity and the thickness of the web is changed in echelon, the former varies from 1 to 0.5 meter and the latter varies from 0.8 to 0.5 meter which changed