碗扣式钢管脚手架节点受力性能研究

针对目前市场上大量使用的碗扣式钢管脚手架,采用非国标与国标两种碗扣式脚手架节点受力性能对比试验的方法,对碗扣节点的半刚性进行了研究。得出了非国标管碗扣的壁厚较薄是造成其碗扣节点先于钢管的屈服而发生脆性断裂破坏主要原因的结论,提出了上碗扣壁厚应不小于6mm以及应加强碗扣式脚手架在生产、租售和使用中有关法规制定和监督落实的建议。     

碗扣式脚手架支撑在桥梁施工中的计算模型

通过对碗扣式脚手架支撑的各节点进行分析,提出了该支撑的计算模型,并提出了相应的计算方法,最后以实际工程应用计算来验证模型的合理性。     

我国建筑脚手架现状及其发展方向

介绍国内脚手架的发展历程及现状,指出我国当前在脚手架方面存在的问题,在进行分析的基础上提出解决的办法和我国脚手架的发展方向。     

碗扣式脚手架在现浇桥梁施工中的计算及应用

按《建筑施工扣件式钢管脚手架安全技术规范》(JGJ130-2001)规定的计算方法,完整验算了某跨线桥施工中支架立杆在桥梁自重及施工活荷载作用下的稳定性和地基承载力,证明施工时采用的支架具有足够的强度、刚度和稳定性,满足施工要求。采用找零立杆的方法,解决了因纵横坡较大不便调整支架高度的问题。     

钢管脚手架相关规范对荷载规定讨论

根据JGJ 162—2008《建筑施工模板安全技术规范》和GB 50009—2012《建筑结构荷载规范》,对JGJ 166—2008《建筑施工碗扣式钢管脚手架安全技术规范》中关于荷载分项系数的取值进行更正,并结合工程实例进行验证对比,结果表明按照更正后的荷载分项系数进行支架模版的设计更加安全合理。目前JGJ 130—2011《建筑施工扣件式钢管脚手架安全技术规范》中关于荷载组合和荷载设计值的规定已经与JGJ 162—2008《建筑施工模板安全技术规范》统一,因此建议新版的《建筑施工碗扣式钢管脚手架安全技术规范》也对此进行修订。     

碗扣式脚手架施工方案论述

碗扣式脚手架是当前一种新型的承插式钢管脚手架。这种脚手架独创了带齿性碗口接头,因其具有安全可靠、稳定性好、配备完善等特点而被大量应用在建筑工程中,并且这种碗扣式脚手架运用在工程中,不仅安全可靠,还节省了资源,更加经济。本文就碗扣式脚手架施工方案进行论述。     

新型碗扣式脚手架在异形结构外立面中的应用

主要结合上海市长宁区中海油大厦项目中采用新型碗扣式脚手架作为外架的方案,使结构施工操作架与外墙装饰操作架二架合一,同时采用外架组合的方式解决结构外立面异形、外架难以设计的问题。     

港澳江南中心大厦碗扣式钢管提升脚手架的应用及高空拆除工艺

1 工程简介 港澳江南中心是一幢现代化超高层建筑,楼宇54层,总高212.8米,其占地面积约1.06万平方米,建筑面积11万多平方米。 本工程采用现浇钢筋混凝土框筒结构。建筑物的外框架大梁是半反梁,大梁和柱外侧均呈凸形。本工程在7-49A层(标高39～193.35     

双排碗扣式钢管脚手架稳定承载力分析

根据双排碗扣式钢管脚手架稳定承载力试验,在铰接体系理论基础上,针对连续立杆和碗扣刚度等因素对脚手架承载力的影响分别进行了理论分析,提出了稳定承载力计算长度系数的修正计算公式,计算结果与试验结果吻合较好。     

直插轮扣式脚手架连接节点的分析与改进

通过回顾施工脚手架的发展历程,引入直插轮扣式新型脚手架,在对其连接节点受力情况进行详细的理论分析后,指出其原始设计上的不足,并提出了两种改进方案。通过方案比选,最终确定采用横杆插头上增设金属插销的改进方案予以实施,目前已经投入到实际应用之中,取得了良好的社会效益与经济效益。     

Investigation of geometric imperfections and joint stiffness of support scaffold systems

This paper describes the findings from various site measurements of geometric imperfections of support scaffold systems, also known as falsework in industry. The measurements consist of out-of-straightness of the standards (uprights), out-of-plumb of the frame and loading eccentricity between the timber bearer and the U-head screw jack. The measurements were taken from different support scaffold construction sites before the pouring of concrete, representing actual initial geometric imperfections and loading eccentricity encountered in practice. The paper also reports the results of support scaffold joint tests. The tests were performed on randomly chosen used components to investigate the joint stiffness for rotations about vertical and horizontal axes. Tests were performed for various joint configurations (two-way, three-way, and four-way connections), bending axes, and loading directions. The statistical analysis of the data is presented in the paper for practical application in modelling and probabilistic assessment of support scaffold systems.     

支撑系统的模拟

对具有不同升降高度、升降机数量和杰克延性的3+3支撑系统的足尺试验进行数值模拟,分析支撑系统性能。介绍了模拟栓接节点、半刚性梁连接及底板偏心的方法。基于Ramberg-Osgood方程,考虑材料非线性,并考虑了轴线不直、表面与轴线不垂直等初始几何缺陷。通过足尺试验得到的破坏荷载和荷载-位移曲线,对非线性分析得到的极限荷载进行修正。数值结果与试验很吻合,表明采用几何非线性和材料非线性分析能很好地研究支撑系统的性能和极限承载力。分析了支撑系统模拟中的一些难题,建立了底板、U型头、栓接节点的力学模型。     

螺栓预紧力对门式刚架端板连接节点刚度影响的研究

对现存门式刚架中出现的螺栓预紧力施加不足的梁柱端板连接节点进行了节点性能的研究。通过节点单向加载试验验证数值模拟方法的有效性,再对各研究节点分别在施加及未施加螺栓预紧力下的节点进行有限元模拟分析。结果表明螺栓未施加预紧力时节点极限承载弯矩变化不大但初始转动刚度有一定程度的削弱。     

Experimental study of semi-rigid joint systems subjected to bending with and without axial force

Socket joints and bolt-ball joints are typical semi-rigid joint systems widely used in spatial structures. In this paper, tests on fifteen joints are carried out to study their mechanical behavior. Three socket joint systems are subjected to bending moment and shear force, and another seven socket joint systems and five bolt-ball joint systems are subjected to bending moment, shear force and axial compressive force. The main characteristics of the moment-rotation relationship for the connections under different loading schemes are summarized and discussed. The results indicate that: (i) both socket and bolt-ball joint systems have good bending stiffness; (ii) the axial compressive force increases the initial bending stiffness of the joints; (iii) the axial compressive force has different effects on the bending moment capacity of different joints; and (iv) the yield process of moment-rotation curves of the joints is shortened due to the action of the axial compressive force.     

SATWE对柱刚域范围的确定方法及其对结构刚度的影响

框架结构和其他结构形式中的框架部分都存在梁柱相交的重叠部分,当此重叠部分相对其跨度较大时,构件交点处会形成刚性节点区域,刚域尺寸的确定会在一定程度上影响结构整体分析结果。采用不同方法确定柱刚域范围对结构的分析结果和设计结果存在差异,尤其是对框架结构和以框架受力为主的部分框支剪力墙结构中的框支框架部分有较大的影响。本文结合现行结构设计规范阐述SATWE软件确定柱刚域范围方法和考虑梁柱刚域对于结构刚度的影响。     

能量系统(火用)经济分析评价方法的探讨

基于     

Comparative experimental study of hot-rolled and cold-formed rectangular hollow sections

Square and rectangular hollow sections are generally produced either by hot-rolling or cold-forming. Cross-sections of nominally similar geometries, but from the two different production routes may vary significantly in terms of their general material properties, geometric imperfections, residual stresses, corner geometry and material response and general structural behaviour and load-carrying capacity. In this paper, an experimental programme comprising tensile coupon tests on flat and corner material, measurements of geometric imperfections and residual stresses, stub column tests and simple and continuous beam tests is described. The results of the tests have been combined with other available test data on square and rectangular hollow sections and analysed. Enhancements in yield and ultimate strengths, beyond those quoted in the respective mill certificates, were observed in the corner regions of the cold-formed sections—these are caused by cold-working of the material during production, and predictive models have been proposed. Initial geometric imperfections were generally low in both the hot-rolled and cold-formed sections, with larger imperfections emerging towards the ends of the cold-formed members—these were attributed largely to the release of through thickness residual stresses, which were themselves quantified. The results of the stub column and simple bending tests were used to assess the current slenderness limits given in Eurocode 3, including the possible dependency on production route, whilst the results of the continuous beam tests were evaluated with reference to the assumptions typically made in plastic analysis and design. Current slenderness limits, assessed on the basis of bending tests, appear appropriate, though the Class 3 slenderness limit, assessed on the basis of compression tests, seems optimistic. Of the features investigated, strain hardening characteristics of the material were identified as being primarily responsible for the differences in structural behaviour between hot-rolled and cold-formed sections.