大跨度敞开式金属屋面板抗风揭模拟试验研究

现有规范标准对大跨度敞开式金属屋面板的设计和施工缺乏合理规定。根据实际火车站屋面板工程,采用沙袋堆载的静载试验方法,进行了760型金属屋面板整体抗风揭试验。分析了该类型屋面板在风吸力作用下承载力、挠度和关键部位的应变分布规律,并研究了采取自攻螺钉、夹具、垫片等加固措施对金属屋面板承载力和破坏形式的影响。试验结果表明,采取合理加固措施可以有效地提高760型金属屋面板的抗风揭承载力。研究成果将为火车站、航站楼等大跨度敞开式金属屋面板的设计与施工提供科学依据,还可以为类似大型场馆金属屋面板体系的加固提供有价值的参考。     

钢筋锈蚀与混凝土破损后屋面板的变形与裂缝研究

对已出现钢筋锈蚀和混凝土破损的 6块大型屋面板进行了试验研究 ,分析了不同破损特征及不同锈蚀度下大型屋面板的变形和裂缝分布 ,为评价服役屋面板的刚度提供了试验依据。     

基于损伤等效的直立锁边屋面板动态抗风揭试验方法

围护结构在台风等极端风下的抗风性能需要依靠动态试验测定，试验周期长导致成本高且模拟研究受限。基于直立锁边屋面板材料的损伤本构模型，通过疲劳分析研究荷载幅值对材料损伤影响，提出简化荷载序列组合。借助雨流计数法统计测点风压时程得到基于损伤等效的简化荷载循环，提出动态抗风揭试验方法。参照不同试验方法开展抗风揭试验，通过对比发现，试验方法对屋面板风揭破坏过程影响不明显。除永久塑性变形外，该文试验方法与现有试验方法下屋面板损坏现象基本一致，屋面板均为撕裂破坏。不同试验方法下屋面板承载力差异在10%～20%间。该文试验方法加载周期小于1h,现有试验方法加载周期则大于20h。在屋面板风揭破坏过程、承载力等抗风揭性能差异不大情况下，该文试验方法可大幅降低试验周期，为开展模拟研究奠定基础。     

杭州大剧院新型屋面系统承载性能的试验研究

杭州大剧院屋面系统采用Kalzip铝合金板作为防水屋面板,装饰层通过连接件固定于屋面板的板肋上。外部荷载主要由屋面板承担,进而传递到檩条上。通过试验研究了屋面系统在各种主要荷载作用下的承载能力,试验的结果可为工程设计提供依据。     

静载法检测预应力混凝土拱形屋面板施工质量的试验研究

论述了预应力混凝土拱形屋面板的结构特点、受力原理及应用范围,提出了预应力混凝土拱形屋面板的试验荷载作用方式及加载步骤。通过对预应力混凝土拱形屋面板所进行的静载试验数据分析,得出不同等级荷载作用下拱板上弦板、下弦板及KB板的应力、挠度及裂缝变化规律。     

加气混凝土屋面板抗弯试验及有限元模拟

通过6块加气混凝土屋面板的抗弯试验,研究板材跨度及板材强度对加气混凝土屋面板的延性、开裂荷载和极限承载力的影响。试验结果表明:加气混凝土屋面板以弯剪破坏为主,承载能力较小,延性比较好。开裂荷载作用下板的变形较大,工程中屋面板的受弯承载力应以变形和强度同时控制比较合理。采用MARC有限元软件模拟分析该楼板的变形和承载力,结果表明,有限元计算与试验结果吻合较好。     

立缝支架屋面体系对Z型檩条扭转约束的试验研究和有限元分析

改变屋面板厚度、檩条厚度、檩条腹板高度、立缝支架形式,对28组压型钢板屋面檩条体系进行足尺试验,研究体系总扭转刚度和影响总扭转刚度的因素。采用ANSYS有限元分析软件建模,分析屋面板、立缝支架和檩条三者的扭转刚度,分析结果与试验结果吻合较好。提出屋面板、立缝支架和檩条的扭转刚度的计算式。将试验结果和有限元分析结果进行对比,得到体系总扭转刚度由屋面板、支架和檩条三者的扭转刚度串联而成。试验和有限元分析结果均表明,影响总扭转刚度最主要的因素是檩条厚度。     

火车站雨棚轻钢屋面抗风承载力试验研究

火车站雨棚通常采用轻钢屋面,跨度大、结构柔,在强风作用下极易发生破坏。轻钢屋面系统经常采用暗扣式连接,此种连接形式在某些工况下并不安全。介绍了某火车站雨棚的轻钢屋面因抗风需要所采用的加固方法,并进行了屋面板区段的承载力试验和夹具抗拔试验,分析了它们的承载力。试验结果表明,加固方法是可行的,能使各个屋面板有效地联成整体,增强抵抗风荷载的能力,但是,最终由于连接屋面板支托的自攻螺钉的抗拉承载力远小于其额定承载力而断裂,造成屋面板整体掀翻破坏。指出了轻钢屋面板应用中自攻螺钉的产品质量问题,提出了解决问题的建议和措施。     

聚氨酯夹芯金属复合屋面板动力特性的试验研究

在传递屋面风荷载的过程中,金属复合屋面板的有限刚度和阻尼特性会改变脉动风的频谱特征,从而影响屋盖结构的风致振动效应.针对75mm和100mm两块典型跨度聚氨酯夹芯屋面板足尺试件,通过数值模拟和试验测试对其动力特性进行研究.基于已有聚氨酯夹芯材料的试验数据,建立了两块屋面板的初始有限元模型,并对其模态特征和阻尼性能进行了初步分析.参照分析结果,开展屋面板足尺试件的动力试验,利用PolyLSCF法识别得到屋面板的模态参数值.测试结果表明,聚氨酯夹芯金属复合屋面板试件的前7阶固有频率在24Hz~60Hz之间,频率分布密集,各阶模态阻尼比在1%~3%之间.以试验识别的固有频率和振型为基准,采用一阶优化方法对初始有限元模型进行修正.分析发现聚氨酯夹芯材料的竖向弹性模量、密度和泊松比是影响屋面板动力特性的敏感参数,支承檩条对屋面板动力特性的影响也不能忽略.将檩条引入初始模型并再次进行模型修正,最终获得的屋面板各项设计参数修正值均保留明确的物理意义,可供此类屋面板的风致振动效应分析及相关研究采用.     

某国际机场航站楼屋面板抗风承载能力试验研究

金属屋面板自20世纪80年代开始引进我国,至今已得到了巨大的发展和广泛的应用,尤其是在大型公共场馆领域,但是,沿海地区或风力较大地区的大型场馆金属屋面经常因受到风荷载的影响而被破坏。对某沿海国际机场航站楼屋面加固工程所采用的65/333型镀铝锌面板的抗风承载能力进行了试验研究,分析了该类型屋面板在风吸力作用下的破坏机理和在屋面板T码上施加锁夹对屋面板抗风压承载力的影响。根据试验结果,对机场屋面采取了经济合理的加固措施,以提高屋面系统抗风荷载承载能力。屋面板的试验不仅为机场屋面加固工程提供科学依据,而且为类似大型场馆金属屋面的加固提供有价值的参考资料。     

铝合金面板试验研究和设计建议

进行了铝镁锰合金屋面板的正向及反向承载力试验,根据试验观察的破坏类型和特征,并结合相关计算理论进行了铝合金屋面板实用设计方法研究。试验现象及试验数据揭示铝镁锰合金屋面板的正向加载破坏主要是弯剪共同作用的结果;反向加载破坏是铝合金支座和板面的连接破坏,且承载力低。本文依托试验数据对铝合金面板和支托的计算公式进行总结和验证。形成了一整套铝合金面板设计方法。     

W-600压型钢板受力蒙皮用于工业厂房的抗剪性能

本文结合工程实例,进行了高波压型板屋面蒙皮作用的试验研究;并首次把蒙皮自身刚度和屋面横向支撑刚度进行了比较。高波压型板屋面具有显著的整体蒙皮效应,板侧连接件和高波板下的承托支架对蒙皮横向刚度的提高起有利影响。     

Lateral buckling of restrained roof purlins

A simple model is developed for the elastic lateral buckling of a continuous cold-formed roof purlin whose top flange is prevented from deflecting laterally, and which is braced against lateral deflection and twist at the supports and intermediate bridge points. The effects of cross-section distortion are neglected, but so are the torsional restraints provided by roof sheeting against twisting. Local buckling is ignored, and must be designed against separately.

The model is analysed by a finite element computer program, and predictions of the maximum moment in a segment at elastic buckling under either uplift or gravity loading are presented graphically.

A simple method of using this elastic buckling information to determine the design working load capacity of a roof purlin is then presented, and this is illustrated by a worked example. An improved method is also presented which allows the restraining effects which occur between adjacent segments during elastic buckling to be estimated. Strength predictions obtained from the improved method are compared with test results.     

Numerical Studies of the Rotational Stiffness of Purlin–Sheeting System

In light-gauged steel purlin-to-sheeting roof systems, the attached sheeting can provide rotational restraints to the purlin. The magnitude of the additional rotational stiffness offered by the sheeting will affect the load bearing capacity of the purlin. The current design method in Eurocode3 (EC3) is less accurate in predicting the purlin–sheeting rotational stiffness as it neglects the effect of wall thickness of the purlin. An integral model is introduced based on the finite element method. Comparisons are made between numerical results and existing experiments and a good agreement is observed. Parametric studies are conducted based on the validated model to investigate the influences of geometric dimensions on the rotational stiffness. Two modified coefficients are proposed for calculating the rotational stiffness based on the codified formulae in EC3, where the effect of the wall thickness and the flange width of the purlin are both considered.     

Experimental and finite element study of profiled steel sheet dry board folded plate structures

Folded plate structures constructed with profiled steel sheeting connected to dry boards by self drilling, self tapping screws (known as the PSSDB system) are being proposed as an alternative to traditional forms of roof construction. This paper describes the analysis, testing, and the structural behaviour of such kind of structures. The proposed efficient and load bearing structural system consists of an assembly of individual PSSDB panels connected by steel angle plates at the ridges, formed to the required shape, width and span. An analytical model using finite element method has been proposed. The profiled steel sheeting was idealised as an equivalent homogeneous orthotropic thin shell plate elements of constant thickness. Two directional plate elements were proposed in modelling the connection between profiled steel sheeting and dry board to include biaxial shear deformation. The proposed analytical method has been used to analyse the results of full-scale folded plate PSSDB tests and is found to give good results.     

多跨连续压型钢板承载力的近似计算

提出了一个估算多跨连续压型钢板极限承载力的近似方法,即拟简单塑性铰方法。该方法考虑了连续压型钢板中的弯矩重分布,能够较为准确地估算多跨连续压型钢板的承载力。与已有文献中的试验相比,该方法估算的承载力是偏于安全的。由该法还得到了估算这种压型钢板在均布荷载下的承载力的显式,便于实际应用。     

轻钢结构考虑蒙皮效应的非线性有限元分析

初步探讨了轻钢结构中屋面压型钢板的蒙皮效应;引入 combin39 弹簧单元模拟连接件,对工程实例进行了非线性有限元分析,给出了考虑蒙皮效应的轻钢结构的量化结果,最后得到一些可供参考的结论。     

Finite element prediction on the structural performance of profiled steel sheet dry board structural composite system proposed as a disaster relief shelter

Folded plate structures constructed from profiled steel sheeting connected to dry boards by self drilling, self tapping screws (known as profiled steel sheeting dry board (PSSDB) system) are being proposed as an alternative to traditional forms of roof construction. The proposed load bearing composite structural system consists of an assembly of individual PSSDB panels connected by steel angle plates at the ridges, formed to the required shape, width and span. This kind of structure has a significant advantage of removing the internal trussing and support that is normally required in a traditional trussed roof system, thus adding to livable space in a building. The introduction of this innovative system would eliminate the difficulty in constructing folded plate roof that is normally very troublesome, especially when they are made out of traditional reinforced concrete system, hence would help promote the folded plate technique of construction. This paper looks into the possibility of employing the PSSDB folded plate structure to provide an efficient emergency shelter, analysing it under the effect of static wind loading using the already established and verified Finite Element technique. Such a structure is quite conceivable in the likely event of a disaster. Firstly, its basic behaviour in the elastic range is studied checking for deflection as the main controlling design factor. Secondly, the method of enhancing the structural stiffness and performance of the system is proposed. It was found that this could be easily achieved by restraining the bottom longitudinal edges on both sides of the structure. A practical solution is proposed in this paper that can be implemented in real practice. It can be concluded that the proposed structure has a great potential to be exploited for the above-intended purpose.     

Investigations concerning the behaviour and load-bearing capacity of built-up light-gauge structures

A V-shaped roof system for spans between 15 and 30 m is presented. The research project has two different purposes—the first is to demonstrate new possibilities for the use of thin-walled structural elements and to prove the efficiency and the competitive position of such structures, and the second is to study different problems concerning the behaviour and load-bearing capacity of structural elements built up by profiled sheeting and thin-walled sections.Some test results concerning the diaphragm action of the webs and the load-bearing capacity of the elastically restrained flange sections are revised.     

Stability of frames restrained by roof sheeting

Formulae have been derived for the calculation of the effective length of a column in a frame restrained by roof sheeting. An example is given to illustrate the advantages resulting from the use of these formulae.