方箱内模现浇混凝土空心楼盖的改进拟梁法及其应用分析

发布时间：2018-06-14 12:05

本文选题：空心楼盖 + 方箱内模　；参考：《湖南大学》2015年硕士论文

【摘要】：现浇钢筋混凝土空心楼盖体系就是近年来应用最广泛的一种新型楼盖技术之一。它自重轻、材料省、刚度大、施工快、综合经济性好,特别适用于大跨度、大荷载建筑的楼盖体系,而且密闭空腔具有隔热降噪的效果,是一种良好的节能结构。在现浇空心楼盖的多种芯模形式中,薄壁方箱内模又以刚度大、空心率高等优点在近些年来被广泛应用。这种楼盖体系的工程设计计算方法多采用弹性简化计算方法,然而它们各自都有相应的优点和不足。本文分析《规程》中介绍的拟梁法并稍作改进,在适用性广的基础上提高了它的精确性,为实际工程的设计提供一定的理论依据和建议,本文主要分以下三个方面:1)综合分析比较各种简化计算方法,评价它们各自的优缺点,针对《规程》中介绍的适用性较好,应用较广泛的拟梁法稍作改进。在柱上板带中应力变化梯度较陡的部位,第一根肋梁单独归并,第二根到靠近边梁1/4处的肋梁归并,中间全部肋梁归并为中间拟梁,并针对其归并后扭转刚度的影响提出相应的方法。然后利用sap2000建立实体单元有限元模型,与同样情况下的PKPM改进拟梁法模型对比,通过内力、位移、挠度、周期的比较来验证该改进方法的准确性。2)受理论水平和研究条件的限制,针对空心楼盖的研究大多处于弹性阶段,对它的破坏机理、破坏形态及破坏特征的认识还存在不足,因此对其弹塑性阶段的受力分析具有很大的意义。本文分别计算出在四边简支情况下空心楼盖的极限承载力和利用改进拟梁法得到的塑性承载力进行对比,其结果也较为接近。因此,使用该改进方法模拟现浇空心楼盖非弹性阶段的受力也具有一定的准确性。柔性支撑空心楼盖不设主次梁,弹塑性阶段形成塑性绞线,现在的大部分结构分析软件大多能很好的模拟框架结构中的塑性铰,对于无梁体系的塑性绞线却无能为力,因此本文采用静力弹塑性分析方法通过对改进拟梁法简化后的计算模型进行弹塑性分析来探索无梁空心楼盖体系的弹塑性分析方法,结果也显示层间位移角都符合规范规定的弹塑性层间位移角要求,整体结构具有很好的耗能抗震能力。3)最后,结合已设计完成的昆山某集团公司研发与会展中心,该项目办公楼区域采用GBF蜂巢芯现浇混凝土空心楼盖体系,板厚400mm,本文采用刚度更大的方箱内模空心楼盖体系,板厚减少为350mm,用改进拟梁法模型重新设计该楼盖,计算内力并配筋。
[Abstract]:Cast-in-place reinforced concrete hollow floor system is one of the most widely used new floor technology in recent years. It is light in weight, low in material, large in rigidity, fast in construction and good in comprehensive economy. It is especially suitable for the floor system of long span and large load buildings, and the airtight cavity has the effect of heat insulation and noise reduction, so it is a good energy-saving structure. In the various core forms of cast-in-place hollow floor, the inner die of thin-walled square box is widely used in recent years with the advantages of high stiffness and high hollow rate. The elastic simplified calculation method is often used in the engineering design of this floor system. However, each of them has its own advantages and disadvantages. In this paper, the quasi-beam method introduced in Code is analyzed and improved, which improves its accuracy on the basis of its wide applicability, and provides some theoretical basis and suggestions for the design of practical engineering. This paper is mainly divided into the following three aspects: (1) Comprehensive analysis and comparison of various simplified calculation methods, evaluation of their respective advantages and disadvantages, in view of the "rules" introduced in the applicability of the better, the more widely used quasi-beam method is slightly improved. Where the stress gradient is steeper in the upper plate zone, the first rib beam is merged alone, the second rib beam is merged to the rib beam near the side beam 1 / 4, and all the middle rib beams merge into the middle pseudo beam. The corresponding method is put forward for the influence of torsional stiffness after merging. Then the finite element model of solid element is established by using sap2000, and compared with the improved quasi-beam model under the same condition, through internal force, displacement, deflection, The accuracy of the improved method is limited by the theoretical level and the research conditions. Most of the research on hollow floor is in the elastic stage, and the understanding of its failure mechanism, failure form and failure characteristics is still insufficient. Therefore, it is of great significance to analyze the stress in the elastic-plastic stage. In this paper, the ultimate bearing capacity of hollow floor under the condition of simply supported on four sides is calculated and compared with the plastic bearing capacity obtained by using the improved pseudo beam method. The results are also close to each other. Therefore, using the improved method to simulate the inelastic stage of cast-in-place hollow floor is also accurate. There are no primary and secondary beams in flexible braced hollow floor, and plastic strands are formed in elastic-plastic stage. Most of the present structural analysis software can simulate plastic hinge in frame structure well, but there is nothing that can be done for plastic strands in beamless systems. Therefore, the static elastoplastic analysis method is used to explore the elastoplastic analysis method of the beamless hollow floor system through the elastic-plastic analysis of the simplified computational model of the improved quasi-beam method. The results also show that the interstory displacement angles are all in line with the elastic-plastic interstory displacement angle requirements stipulated in the code, and the overall structure has a good seismic energy dissipation capacity. Finally, combined with the research and development and exhibition center of a group company in Kunshan, which has been designed and completed, The GBF honeycomb core cast-in-place concrete hollow floor system is used in the office building area of the project, and the slab thickness is 400mm. In this paper, the square box inner mold hollow floor system with greater stiffness is adopted, the slab thickness is reduced to 350 mm, and the floor is redesigned with the improved quasi-beam model. Calculate internal force and reinforcement.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU755

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