【作者】 李强；

【导师】 吕伟荣；

【作者基本信息】 湖南科技大学 ， 土木工程， 2017， 硕士

【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。更多还原

【Abstract】 The large span cast in situ concrete hollow floor is a new type of structural system,which is a kind of floor slab structure.Due to the adoption of wide flat beam members,the structure can effectively reduce the storey height and increase the use area.At the same time,hollow floor also has a good mechanical performance,such as reducing weight,reducing seismic action,and it is a kind of structural form which combines the mechanical properties and the use function.At present,the domestic and foreign research on this structural system mainly concentrated bending and shearing test and theoretical research on mechanical properties of the single piece of hollow floor,seismic research and for considering the wide flat beam constraint effect on multi slab overall study on mechanical properties and application of large span hollow slab in high-rise buildings is relatively small.In this paper,through the field test and numerical simulation,the vertical bearing mechanism and seismic performance of long span hollow floor are studied:(1)The results of field tests show that the vertical loading,large span hollow slab beam flat bandwidth can meet the requirement of the current standard of floor serviceability limit state of deflection.At the same time,due to the wide flat beam height is not enough,can not achieve the effective restraint of the hollow plate,making the 2 plates of the vertical deformation curve presents the characteristics of single plate.(2)Based on the hollow layered shell element for large span hollow slab,finite element analysis results show that the increase of beam height can effectively improve the constraint on wide flat beam on the surrounding hollow floor,and according to the characteristics of section shape and stress distribution of the hollow plate,put forward the calculation method of the crack tube core type hollow slab,the calculation results agree well with the experimental results.(3)Response spectrum analysis results show that the wide flat beam hollow floor structure due to height than the ordinary ribbed floor structure of lo w layer,high stiffness,small elastic deformation,easier to meet the requirement of deformation;torsional period of wide flat beam hollow floor structure of the larger proportion,proposed to increase the inner cylinder size or method of rigidity of the beam frame side to increase improve the overall structure of the torsional stiffness.125 gal elastoplastic analysis results show that the floor of ordinary reinforced ribbed floor structure with wide flat beam hollow floor structure of the maximum stress value was 8.4MPa and 188.0MPa,the stress of wide flat beam hollow floor reinforcement stress is larger than that of ordinary reinforced ribbed floor slab reinforcement,stress distribution range is greater than the ordinary rib floor,illustrate the role of wide flat beam hollow floor slab reinforcement structure is significantly larger than normal ribbed floor structure.(4)Under the rare earthquake incremental dynamic elastic-plastic time history analysis(IDA)results show that with the increase of se ismic action,wide flat beam hollow floor structure stiffness degradation than ordinary ribbed floor structure,damage,damping increasing,cycle extension,vertex displacement reaction is elastic phase lag significantly,energy dissipation capacity strong.The stress nephogram of the upper surface of the first floor under different earthquake action shows that the damage degree of the wide flat beam hollow floor is deeper than that of the ordinary rib beam floor,the damage range is wider,and the energy dissipation capacity is more favorable than that of the 2.However,due to the lack of stiffness of the wide flat beam,it can not form an effective restraint to the floor,and the mechanical performance of the floor shows the characteristics of the opposite side load between the shear wall and the frame beam.Wide flat beam hollow floor structure shear wall reinforcement stress on each floor floor than ordinary ribbed floor structure is serious,indicates that the structure of the shear wall stress of high performance requirements,should be highly valued,suggestions for the improvement of wide flat beam hollow floor outside shear wall longitudinal reinforcement ratio or with the dark out of plane beam column and ensure performance of the shear wall.更多还原