【作者】 蒋海波；

【导师】 赵慧娟；

【作者基本信息】 西南交通大学 ， 结构工程， 2009， 硕士

【摘要】 转换层可以实现高层建筑上下部不同结构形式之间的转换,在高层建筑中设置转换层可使同一座建筑具有不同的使用功能。在众多的转换层结构中,转换厚板是一种较为常见的结构形式。转换厚板的厚度可达2.0m以上,因此转换层的自重和施工荷载非常大,这使得厚板底部的模板支撑设计变得困难。为了解决厚板现浇高空支模这一施工问题,我们可以将转换层厚板分两次浇筑,利用第一次浇筑的混凝土所形成的板来支承第二次浇筑的混凝土的自重及施工荷载。厚板分层浇筑时,厚板下部框支柱所受弯矩与厚板一次整体浇筑时所受的弯矩值是不同的,它们之间的“差值”与框支柱的承载能力设计值相比到底有多大?在框支柱的设计中是否应考虑这个“差值”的影响?这将是本文分析的第一个主要问题。二次受力叠合结构的底部受拉钢筋具有应力超前的现象,应力超前会导致结构的裂缝宽度及挠度增大,并使得纵向受拉钢筋较早地达到屈服强度;如果应力超前值过大,则会引起结构的安全储备严重降低,进而不能满足正常的使用要求。转换层厚板分层叠合浇筑所导致的板底受拉钢筋应力超前值到底有多大?对厚板底筋受力是否有较大影响?这是本文分析的第二个主要问题。本文将用SAP2000建立一个带厚板转换层结构的高层建筑有限元模型,并选择转换厚板下部几根有代表性的框支柱及厚板中有代表性的几个点位作为验算的对象。通过验算厚板不同分层浇筑厚度下的框支柱弯矩及厚板底筋应力,来分析本文所提出的两个问题。更多还原

【Abstract】 Transfer story can be used to connect the different structural style of tall building, which makes the same building have different service functions. Thick transfer slab is a familiar transfer member.The thickness of thick transfer slab can exceed 2m, so the dead weigh and the construction load are huge, which makes it difficult to design the bracing system of formwork. That difficulty can be solved by layer-pour construction method. This method use the slab formed by the pre-pour concrete to support the dead weigh and the construction load of the post-pour concrete.Compared with the moment of frame columns under the thick transfer slab poured monolithically, the moment of frame columns vary when the thick transfer is poured by two times. In other words, the layer-pour construction method will influence the moment of frame columns. How large will the influence on moment be? Is it necessary to consider this influence when we design the frame columns? Which is the first problem discussed in this paper.There is a characteristic of "stress excess of reinforcement" in the two-stage loading composite structure. Stress excess will cause larger crack width and bending deflection, which leads the tensile reinforcement yield early. Larger stress excess will decrease the safety stock of structure, in this circumstances, the structure may lost the normal serviceability. How large is the stress excess of tensile reinforcement when the thick transfer slab has been build by layer-pour construction method? This will be the second problem discussed in this paper.A tall building finite element model will be build by SAP2000. We will select several representative frame columns and points in the thick transfer slab, then we will analyze those two problems mentioned above by means of checking their moment or stress under the condition that the thick transfer slab’s pre-pour layer has different thickness.更多还原