框剪结构中侧向约束对预应力效应影响的研究

发布时间：2018-07-03 11:32

本文选题：框剪结构 + 预应力效应　；参考：《兰州交通大学》2017年硕士论文

【摘要】：后张预应力混凝土结构,现有的规范和规程都是基于端部无约束梁的工作原理建立的公式来对其进行结构抗裂验算、截面承载力计算,因此对简支梁、连续梁及没有侧向约束影响的预应力结构比较适用,而对于有侧向约束的预应力结构,竖向构件的侧向约束对预应力梁的轴向变形有一定的约束作用,因而影响预应力在梁内的传递,造成预应力损失,导致预应力梁的有效预应力降低。框剪结构中采用预应力结构,剪力墙侧向刚度比较大,对有效预应力的影响较大。本文以兰州市榆中县新世界商业中心工程为背景,采用等效荷载法,通过有限元软件SAP2000,研究了框剪结构中单跨、多跨、多层预应力梁在侧向约束作用下的预应力损失,探讨不同张拉方案下预应力梁的预应力损失规律,结合国内外研究成果从设计和施工构造方面给出了减小侧向约束对预应力效应影响的措施,主要结论如下:(1)剪力墙侧向刚度越大,梁内预应力损失值越大;随着梁的跨度增大,梁内预应力损失值越大;不同大小的张拉力作用下梁内预应力损失值近似相同,张拉力的大小对预应力效应没有影响。(2)随着跨数的增多,侧向构件越多,侧向约束越大,跨内最大预应力损失值越大;多跨结构中剪力墙靠近中间跨时梁中的最大预应力损失值最小,即较大侧向约束构件靠近中间处越近侧向约束对预应力效应的影响越小。(3)多层结构整体一次张拉时,梁中最大预应力损失值出现在最低层;多层结构逐层浇筑逐层张拉时,梁中最大预应力损失值出现在最顶层。(4)不同的张拉施工方法、合理的施工顺序组成的混合施工能避免结构整体浇筑一次张拉法及逐层浇筑逐层张拉法所出现的最不利影响。
[Abstract]:For post-tensioned prestressed concrete structures, the existing codes and regulations are based on the formula established by the working principle of the end unconstrained beam to calculate the crack resistance of the structure and the bearing capacity of the section. Continuous beams and prestressed structures without lateral constraints are more suitable, but for prestressed structures with lateral constraints, the lateral constraints of vertical members have a certain constraint on the axial deformation of prestressed beams. Therefore, the transmission of prestress in the beam is affected, which results in the loss of the prestress and the reduction of the effective prestress of the prestressed beam. In frame shear structure, the lateral stiffness of shear wall is relatively large, which has a great influence on effective prestress. Based on the project of New World Commercial Center in Yuzhong County, Lanzhou City, this paper studies the prestressing loss of single-span and multi-story prestressed beams in frame-shear structures under lateral restraint by using equivalent load method and finite element software SAP2000. This paper probes into the law of prestress loss of prestressed beams under different tensioning schemes, and puts forward some measures to reduce the influence of lateral restraint on the prestress effect from the aspects of design and construction structure combined with the domestic and foreign research results. The main conclusions are as follows: (1) the larger the lateral stiffness of the shear wall, the greater the loss value of the prestressing force in the beam; the greater the loss value of the prestress in the beam is with the increase of the span of the beam; The magnitude of tensile force has no effect on the prestress effect. (2) with the increase of the number of spans, the more lateral members, the greater the lateral constraint, the greater the maximum loss of prestress in the span; In multi-span structure, the maximum prestress loss value of shear wall near intermediate span beam is the minimum, that is, the larger lateral restrained member is near the middle, the smaller the influence of lateral constraint on the prestressing effect. (3) when the multistory structure is in a single tension, The maximum prestress loss value in the beam appears in the lowest layer, and the maximum prestress loss value in the beam appears at the top layer when the multi-story structure is tensioned layer by story. (4) different construction methods of tensioning, The mixed construction composed of reasonable construction sequence can avoid the most adverse effects of the one-time tensile method and the storie-by-layer tensile method of the whole structure.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU973

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