某厚板转换层结构的分析与设计

在总结以往厚板转换层结构分析方法的基础上,结合工程实例,采用计算软件Midas对厚板转换层结构用混合单元建立整体结构计算模型,转换厚板采用三维实体单元,并考虑了地震作用,得出了转换板较真实的应力和位移,并据此提出了设计建议,供相关设计参考.     

乾鸿苑大厦预应力厚板转换层结构设计

简要介绍上海乾苑大厦预应力厚板转换层结构设计,其内容包括结构选型、三维空间结构整体分析、预应力厚板设计、厚板转换层上下剪切刚度比控制、构造措施等。这些设计内容可供类似的结构参考。     

高层商住楼厚板转换层施工技术

本文结合工程实例,探讨了高层建筑厚板结构转换层的结构设计方案,并从模板支设、钢筋绑扎、混凝土工程等方面详细阐述了厚板结构转换层的施工技术工艺和质量保证措施。     

转换层施工技术在高层商住楼厚板中的应用

本文结合工程实例,探讨了高层建筑厚板结构转换层的结构设计方案,并从模板支设、钢筋绑扎、混凝土工程等方面详细阐述了厚板结构转换层的施工技术工艺和质量保证措施。     

转换层施工技术在高层商住楼厚板中的应用

本文结合工程实例,探讨了高层建筑厚板结构转换层的结构设计方案,并从模板支设、钢筋绑扎、混凝土工程等方面详细阐述了厚板结构转换层的施工技术工艺和质量保证措施。     

公寓转换层厚板支撑体系施工

深航飞行员公寓地下 2层 ,地上2 5层 (裙房 3层 ) ,总建筑面积6 9787 8ｍ2 。该工程 3层顶板采用了厚板结构转换层 ,板厚 2 4ｍ。该层框架柱柱网尺寸为 10 4ｍ× 10 4ｍ和 9 6ｍ× 9 6ｍ ,柱截面尺寸为 16 0 0ｍｍ×16 0 0ｍｍ。转换层厚板在结构周边大部分设计为悬挑形式 ,悬挑长度 3 2 5ｍ。经分析、计算 ,确定了厚板混凝土分 3层浇筑 ,框架柱网内采用 1层满堂脚手架及柱网外采用悬挑钢梁加满堂脚手架进行支撑的施工方案。具体如下 :先施工第 1层 5 0 0ｍｍ厚板 ,待此层混凝土强度达到 10 0 %后再进行第 2层6 0 0ｍｍ厚板的施工 ,最后…     

带厚板转换层高层建筑的结构设计

本文结合一工程买例.探讨了带厚板转换层高层建筑结构设计中遇到的一些问题,如厚板转换层上、下刚度比的调整方法、厚板的设计、短柱的设计等,对工程设计有一定的参考作用。     

对高层混凝土结构1.6m厚板式转换层叠合法施工的研究

厚板转换层是工程结构的关键部位,施工难度大,本文结合中天广场工程实例,对厚板结构利用叠合法施工原理支撑系统的设计与施工进行了研究,阐述了厚板暗梁、板钢筋及大体积混凝土的施工方案及防止温差、收缩裂纹的各项技术措施,为同类结构工程提供参考及施工经验。     

对高层混凝土结构1.6m厚板式转换层叠合法施工的研究

厚板转换层是工程结构的关键部位,施工难度大。本文结合长沙市某工程实例,对厚板结构利用叠合法施工原理支撑系统的设计与施工进行了研究,阐述了厚板暗梁、板钢筋及大体积混凝土的施工方案及防止温差、收缩裂纹的各项技术措施,为同类结构工程提供参考及施工经验。     

对高层混凝土结构1.6m厚板式转换层叠合法施工的研究

厚板转换层是工程结构的关键部位，施工难度大。本文结合长沙市某工程实例，对厚板结构利用叠合法施工原理支撑系统的设计与施工进行了研究，阐述了厚板暗梁、板钢筋及大体积混凝土的施工方案及防止温差、收缩裂纹的各项技术措施，为同类结构工程提供参考及施工经验。     

超厚混凝土转换板及支撑的施工方法

某工程在施工过程中需设置转换,使楼板由200mm经过转换变为800mm,由于楼板超厚,给模板支顶和混凝土浇筑带来许多困难,在施工中通过采用转换板、模板支护体系的设计及各分项工程施工时,相互配合以及一些特殊做法和节点处理等相应措施,保质保量地完成了任务。     

Development of floor slab for steel post-tensioned self-centering moment frames

A floor slab constructed in conventional moment-resisting frames (MRFs) limits opening of gaps at the beam-to-column interfaces, causing losses of self-centering capability and preventing its use in steel post-tensioned (PT) moment frames. This work presents two novel slab schemes to reduce the restraints on the seismic responses of a PT frame. The first scheme uses a slab in typical MRFs with a modification so that near the connection, the metal deck is discontinuous and the longitudinal bar in the deck is debonded from concrete to minimize slab restraints. The second scheme uses truss elements to connect the slab and beams in only one bay (rigid bay) of the PT frame for transferring inertial forces from the floor to the frame. The sliding device is provided at one end of floor beams transverse to the PT frame, where sliding of the slab is expected. The cyclic behaviors of the bare connection and the connection with the first slab scheme are also evaluated by testing four connections. Additionally, how the rigid bay affects the cyclic behavior of the frame, distribution of column shear, beam axial force variation, and gap opening response near the beam-to-column interface is evaluated by conducting frame subassembly tests. The test results demonstrate that (1) the PT frame with any of two slab schemes develops large deformation capacities with small residual deformations, and (2) the column shear and beam axial force can be estimated based on the proposed method.     

预应力混凝土叠合空心楼板静力性能试验研究

结合现浇空心楼板与叠合楼板的优点,提出在一种预应力叠合楼板中布置筒芯内模形成的叠合空心楼板。进行了预制带肋底板叠合空心楼板、矩形底板叠合空心楼板及现浇空心楼板3种截面形式,2种截面尺寸分别为230mm×500mm、300mm×600mm的10块板带在单调荷载作用下的足尺模型试验。通过改变预制底板类别、筒芯内模的直径及其布置方式,对叠合空心板带的破坏形态、截面整体工作性能、正截面受弯承载力、短期刚度、叠合面水平受剪性能等进行了研究。结果表明：从开始加载到破坏,叠合空心楼板与现浇空心楼板表现出相似的受力特点和变形特征,按筒芯最薄弱翼缘处的工形截面计算叠合板的开裂荷载、正截面受弯承载力、平均裂缝间距等与实测值吻合较好;在所研究的板厚范围内,筒芯直径大小及布置方式的变化并未造成叠合面出现滑移开裂的现象,但不同程度地削弱了试件的受拉刚化作用,建议叠合空心楼板开裂后的短期刚度取控制截面的开裂刚度。通过叠合面受力分析,将横孔板顺筒肋宽度和上、下翼缘厚度的计算限值与楼板实际构造尺寸进行对比,实际工程中叠合面的抗剪强度可满足安全使用要求。两种预制底板预应力混凝土叠合空心楼板与预应力现浇空心楼板的总体受力性能较为接近,均可满足工程设计要求。     

"三拆一"楼板支模方案的荷载传递计算

在多层现浇混凝土结构施工中，建立“三拆一”楼板模板支撑的荷载传递计算的力学模型，可分析各层楼板受到的荷载，核算楼板在施工阶段承载力是否安全。该计算方法对确定有转换层的支撑方案计算尤为实用。     

深圳现代商务大厦桁架转换层结构设计

现代商务大厦为超限高层建筑,结构总高度186.20m。在层6通过型钢混凝土桁架将上部外框架密柱转换为落地疏柱。针对桁架转换结构特点,研究了桁架转换层对结构整体抗侧刚度的影响,详细计算了桁架内力和转换层及其上层楼板的应力及分布,介绍了转换桁架及其上下层楼板的设计。计算结果表明,桁架转换具有传力明确,传力路径清楚,结构刚度、质量变化较为均匀等优点。     

Development of interlocking mechanism for shear transfer in composite floor

Semi-pre-cast floor slab (called half slab in Malaysia) has been used widely in different parts of the world. It consists of a reinforced concrete pre-cast layer that acts initially as a formwork connected in situ with another concrete layer using shear connectors. Steel reinforcement (shear link, studs and/or steel truss) is commonly used to transfer the horizontal shear between the two composite layers. Longitudinal shear failure is the most common type of failure in the composite floor slab. This paper proposes a new system to transfer the horizontal shear between the interfaces of the pre-cast and cast in situ layers of concrete slab. The proposed system implements an interlocking concept and does not require any shear reinforcement. The composite floor slab used to illustrate the interlocking concept consists of a pre-cast inverted ferrocement layer interconnected with the cast in situ brick–mortar layer. The effectiveness of the interlocking mechanism in transferring the stresses developed due to the applied load is investigated. Eleven composite slab specimens having different shear connectors between the two layers were cast and tested under pure shear loading (push-off test). In the tested specimens, different interlocking mechanisms, continuous truss shear connectors and no connectivity between the two layers were used to connect the layers of slabs. The results indicate that the interlocking mechanism proposed is, as effective as, the steel trusses in resisting shear stresses and can be used to replace the steel trusses, which in turn will reduce the cost of the composite slab.     

The behaviour of reinforced concrete slabs in fire

In this paper a robust model is presented based on the previous layer procedure developed by the author to also take into account the effects of concrete spalling on the behaviour of concrete slabs under fire conditions. In this study, a detailed analysis of a uniformly loaded reinforced concrete slab subject to different degrees of concrete spalling under a standard fire regime is first carried out. Further, a series of analysis of floor slabs with different degrees of concrete spalling is also performed on a generic reinforced concrete building. A total of 16 cases have been analysed using different degrees of spalling on the slabs, with different extents and positions of localised fire compartments. It is clear that adjacent cool structures provide considerable thermal restraint to the floor slabs within the fire compartment. And it is evident that the compressive membrane force within the slabs is a major player in reducing the impact of concrete spalling on the structural behaviour of floor slabs in fire.     

轻质芯模混凝土叠合密肋楼板技术经济分析

为全面掌握轻质密肋楼板以及采用这种楼板的建筑结构的技术经济特点,对单块轻质密肋楼板和采用轻质密肋楼板的建筑结构的技术经济性能进行了深入分析。分析结果表明:轻质密肋楼板结构性能好、安全储备很高且具有良好的适用性;西安地区某六层普通现浇平板框架建筑,若采用轻质密肋楼板,结构总质量减小,相应地地震力减小,在与普通平板建筑结构最大层间位移角接近的情况下,其基础、框架柱、梁等的截面尺寸可以大幅减小,基础、梁、柱等结构构件的配筋量也大幅减小,结构性能有所改善;主体结构造价节约20.34%,节约钢材、模板和混凝土,建设工期将大幅缩短。     

某图书馆预应力框架梁施工裂缝评价与处理

某图书馆局部采用了6层跨度为17.6 m的预应力混凝土框架。由于三层梁板施工时支撑紧张,在未对一、二层框架梁中预应力筋实施张拉条件下即将一层支撑移至了三层,致使一层框架梁跨中部分区域出现最大宽度达1.0 mm、延伸到板底的多条裂缝。尽管对一、二层框架梁中预应力筋进行了及时补拉,补拉后大部分裂缝已趋于闭合,但框架梁个别残余裂缝宽度仍有0.1 mm左右。分析了施工阶段预应力混凝土框架梁出现裂缝的原因,对出现裂缝的框架梁进行了评价,提出了裂缝处理方法,可供处理同类工程事故时参考。     

25.2m跨一次性加载框架结构的设计与施工

本文介绍了国检大厦附楼为实现首层大空间,采取由屋面梁向下设吊柱反向支承二层梁板的特殊框架设计技术,对屋面结构大梁在三种不同输入条件下的内力比较及最终设计选定;附楼结构施工中介绍了高排支撑的搭设、600mm×3000mm屋面大梁的施工方法及满足一次加载的支撑拆除方案。