高层大跨度现浇空心楼盖受力机理及抗震性能研究

发布时间：2018-05-14 03:09

本文选题：空心楼盖 + 宽扁梁　；参考：《湖南科技大学》2017年硕士论文

【摘要】：大跨度现浇混凝土空心楼盖是一种新型的结构体系,它是由双向密肋发展而来的一种无梁楼盖结构。由于采用了宽扁梁构件,这种结构能有效的降低层高,增加使用面积。同时,空心楼盖还具有降低自重,减少地震作用等良好的力学性能,是一种集力学性能和使用功能相对全面的结构形式,有着良好的推广应用价值。当前,国内外关于此结构体系的研究主要集中在单块空心楼盖抗弯、抗剪受力性能的试验和理论研究,而对于考虑宽扁梁约束效应的多块板整体受力性能的研究和大跨度空心楼盖应用于高层建筑中的抗震研究相对较少。为此,本文通过现场试验和数值模拟,对大跨度空心楼盖竖向受力机理和大震作用下的抗震性能展开研究,取得以下研究成果:(1)现场竖向加载试验结果表明,带宽扁暗梁的大跨度空心楼盖能满足现行规范对楼板正常使用极限状态对挠度和裂缝宽度的要求。同时,由于宽扁梁高度不够,未能实现对空心板的有效约束,使得2块板的竖向变形曲线呈现单块板的特征。(2)基于“空心层”分层壳单元的大跨度空心楼盖有限元分析表结果表明,增加梁高度能有效地提高宽扁梁对周边空心楼盖的约束作用,并根据筒芯空心楼盖的截面形状特征及应力分布情况,提出了筒芯式空心楼盖的裂缝计算方法,其计算结果与试验结果吻合良好。(3)反应谱分析结果表明,宽扁梁空心楼盖结构由于层高比普通肋梁楼盖结构低,层刚度大,弹性变形小,更容易满足变形要求;宽扁梁空心楼盖结构的扭转周期占比较大,建议增加内筒尺寸或加大框架边梁刚度的方法以提高整体结构的抗扭刚度。125gal弹塑性分析结果表明,普通肋梁楼盖结构与宽扁梁空心楼盖结构的楼面钢筋应力最大值分别为8.4MPa、188.0MPa,宽扁梁空心楼盖钢筋应力明显大于普通肋梁楼盖钢筋的应力,空心板上钢筋应力分布范围也大于普通肋梁楼盖,说明宽扁梁空心楼盖结构中楼板钢筋的参与作用明显大于普通肋梁楼盖结构。(4)罕遇地震作用下增量动力弹塑性时程分析(IDA)结果表明,随着地震作用的加大,宽扁梁空心楼盖结构的刚度退化较普通肋梁楼盖结构明显,损伤加剧,阻尼增大,周期延长,结构顶点位移反应较弹性阶段滞后明显,耗能能力较强。从2种结构在不同地震作用下首层上表面钢筋应力云图得知,宽扁梁空心楼盖相对于普通肋梁楼盖的损伤程度更深、损伤范围更广,耗能能力更加优越。但是,由于宽扁梁的刚度不足,无法对楼板形成有效的约束,楼板受力性能呈现剪力墙与框架边梁间对边导荷的特点。宽扁梁空心楼盖结构外剪力墙钢筋应力在各楼层楼面处较普通肋梁楼盖结构集中严重,表明此类结构对剪力墙平面外受力性能要求较高,应予以高度重视,建议提高宽扁梁空心楼盖处外剪力墙的纵向配筋率或增设暗柱和暗梁保证其剪力墙平面外性能。
[Abstract]:Large span cast-in-place concrete hollow floor is a new type of structure system, which is a kind of beamless floor structure developed from two-way multi-ribbed structure. Due to the use of wide flat beam members, this structure can effectively reduce the height of the floor and increase the service area. At the same time, hollow floor has good mechanical properties, such as reducing weight and earthquake action. It is a relatively comprehensive structural form with comprehensive mechanical properties and functions, and has a good value of popularization and application. At present, the research on this structure system at home and abroad mainly focuses on the experimental and theoretical research on the bending and shear behavior of single hollow floor. However, there are few researches on the overall mechanical behavior of multi-slab considering the constraint effect of wide flat beam and the application of long-span hollow floor in high-rise building. In this paper, through field test and numerical simulation, the vertical force mechanism and seismic behavior of large-span hollow floor are studied. The following research results are obtained: 1) the field vertical loading test results show that, The large span hollow floor of flat beam with wide bandwidth can meet the requirement of deflection and crack width for the limit state of normal use of floor slab in current code. At the same time, because the height of the wide flat beam is not enough, the effective constraint on the hollow slab can not be realized. The vertical deformation curve of the two plates presents the characteristics of a single slab. The finite element analysis of the large-span hollow floor is based on the "hollow layer" layered shell element. Increasing the height of the beam can effectively improve the restraint effect of the wide flat beam on the peripheral hollow floor. According to the shape characteristics of the section and the stress distribution of the tubular hollow floor, the crack calculation method of the tubular hollow floor is put forward. The calculated results are in good agreement with the experimental results. The results of response spectrum analysis show that the hollow floor structure with wide flat beam is easier to meet the requirements of deformation because of its lower floor height than that of the common rib beam floor structure, large floor stiffness and small elastic deformation. The torsional period of hollow floor structure with wide flat beam occupies a large proportion. The method of increasing the size of inner cylinder or increasing the stiffness of frame side beam is suggested to improve the torsional stiffness of the whole structure. 125gal elastoplastic analysis results show that, The maximum stress of steel bar on the floor of the common rib beam floor structure and the wide flat beam hollow floor structure is 8.4 MPA and 188.0 MPa, respectively. The stress of the wide flat beam hollow floor steel bar is obviously greater than that of the common rib beam floor steel bar. The stress distribution range of steel bar on hollow slab is larger than that of common rib beam floor. The results show that the participation of floor reinforcement in the hollow floor structure with wide flat beam is obviously greater than that in the common ribbed beam floor structure under rare earthquake. The results show that with the increase of earthquake action, the increment dynamic elastoplastic time history analysis shows that, with the increase of earthquake action, The stiffness degradation of the hollow floor structure with wide flat beam is more obvious than that of the common rib beam floor structure, the damage is aggravated, the damping is increased, the period is prolonged, the displacement response of the structure is obviously delayed than that of the elastic stage, and the energy dissipation ability is stronger. According to the stress cloud diagram of steel bar on the top surface of the first floor of the two structures under different earthquake action, the damage degree of the hollow floor with wide flat beam is deeper than that of the common rib beam floor, the damage range is wider, and the energy dissipation capacity is more superior. However, due to the lack of stiffness of the broad flat beam, it is unable to form an effective constraint on the floor, and the mechanical behavior of the floor presents the characteristics of the shear wall and the side beam of the frame. The outside shear wall stress of hollow floor structure with wide flat beam is more serious than that of common rib beam floor structure on each floor, which indicates that this kind of structure requires high stress performance outside the plane of shear wall and should be attached great importance to. It is suggested to increase the longitudinal reinforcement ratio of the external shear wall at the hollow floor with wide flat beam or to add dark columns and beams to ensure the out-of-plane performance of the shear wall.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU973

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