内加劲环间距对X型圆管相贯节点性能的影响

为了研究内加劲环间距对X型圆管相贯节点性能的影响,对加劲环设置情况各不相同的4个X型相贯节点试件进行试验研究与有限元分析.介绍了试验方案、有限元模型,并对试验和有限元计算结果进行对比分析.结果表明:内加劲环的设置对X型节点受力性能有一定的提高;当位于主支管相贯范围内,内加劲环对节点的强度、刚度等受力性能的提高幅度较大;...     

上海旗忠网球中心屋盖支座圆管节点强度研究

以上海旗忠网球中心可开闭屋盖支座节点为工程背景,探讨了由7根支管和1根主管焊接而成的复杂空间多支管节点静力强度。首先进行了两个1∶3的缩尺模型节点静力对比试验,一个节点的主管中不设置加劲板,另一个节点在主管内设置了环向加劲板。试验研究了节点的破坏模式、应力分布、塑性发展、承载能力,观察了加劲板对节点性能的影响。其次,应用有限元方法对两个所试验的模型节点受力性能进行了数值分析,将计算结果与试验结果作了比较,表明有限元数值分析有效可靠。最后,讨论了增强复杂管节点强度的措施,进行了环向加劲板构造参数的有限元分析。研究表明主管径大壁薄、多支管的空间圆管节点在支管有拉有压的情况下很容易发生主管屈服破坏,设计时建议在主管内布置环向加劲板来保证节点刚度和强度,须根据支管轴力大小、拉压性质、支管与主管相交位置等因素来精心设计加劲板的位置和数量。加劲板的厚度不宜小于主管的壁厚,加劲板中心开孔的直径不宜大于0.5倍的主管直径。     

L形加劲板方钢管混凝土柱-型钢梁节点性能研究

钢管混凝土柱与梁的节点构造和受力分析是发展组合结构体系的关键技术, 利用ANSYS有限元分析软件,对钢管混凝土柱与型钢梁的一个新型节点进行了空间非线性有限元分析,分析了对称荷载作用下该节点内的应力分布情况和内力传递机理.同时,通过改变加劲板的参数,分析了影响节点刚度的主要因素,确定了影响节点刚度的各参数对外部T形加劲节点刚度的影响规律.结果表明:通过设置加劲板有效地降低了节点的应力集中,使其在钢梁中部产生了明显的塑性铰,从而降低了节点破坏的可能性.通过综合分析影响加劲板的参数,提出了该类型节点改进的建议.     

平面钢管桁架管内加劲相贯节点有限元分析和试验研究

焊接钢管桁架有时需要在节点区设置加劲肋。对焊接钢管内加劲相贯节点进行有限元分析 ,探讨了管内加劲节点的传力路径 ,通过缩尺模型试验验证了有限元分析结果。针对节点区应力集中 ,提出有效缓解应力集中的构造措施。有限元分析表明 ,管内加劲节点中的加劲肋是重要的受力部件 ,为该节点的设计提供了理论依据。     

内加劲环的设置对钢管节点性能的影响

本首先介绍了越南国家体育场鼓型钢管节点试验的有关情况．然后利用有限元计算比较了鼓型钢管节点在加劲和无加劲条件下的极限承载力和刚度，并通过若干算例比较了在不同内加劲环参数组合下X型钢管节点的极限承载力．结果表明，内加劲环可以提高钢管节点极限承载力和刚度．     

设置加劲肋圆钢管T型相贯节点面内抗弯承载力试验研究及模拟分析

为提高相贯节点的承载力和疲劳寿命,在节点区域设置加劲肋,开展设置加劲肋T型圆钢管相贯节点面内抗弯承载力的试验研究,探讨了设置加劲肋T型相贯节点的破坏模式、应变发展规律和抗弯承载力特性;试验中主管受压侧加劲肋附近应变发展较快,当节点荷载临近极限承载力时,节点主管受压侧加劲肋附近发生明显凹陷的局部屈曲,同时加劲肋发生面外弯曲失稳;设置加劲肋节点面内抗弯承载力比无加劲肋节点承载力明显提高,说明设置加劲肋后有效提高了节点抵抗变形的能力,增加了节点的刚度和强度,使节点承载力有大幅度的提升。同时,开展相贯节点的非线性有限元模拟,分析得到节点的失效模式、承载力与试验均吻合较好。基于非线性有限元模拟,考察加劲肋布置方式对抗弯承载力的影响,提出了合理的加劲肋布置方式。     

加劲板对钢空腹夹层板剪力键节点静力特性影响分析

剪力键节点域是保证钢空腹夹层板空间协同工作的关键节点。为研究加劲板对剪力键节点域静力特性的影响,基于通用有限元分析软件,建立4组考虑材料非线性的节点域平面受剪状态数值模型。分析了设置加劲板对节点域受力及变形状态的影响,并选取加劲板宽度、方钢管厚度、剪力键高度作为变量进行参数化分析。分析结果表明,加劲板可以有效降低节点域方钢管的应力,保证节点域整体变形的特性,避免出现反弯点。根据不同因素的影响程度,发现加劲板的宽度对节点域的静力性能影响最大,提出了加劲板设置的合理尺寸范围的建议值,分析结论可为类似工程应用提供参考。     

箱型钢柱和H型钢梁节点抗侧力作用下加劲板设置研究

对水平作用下箱型钢柱和H型钢梁节点柱内加劲板的设置进行了分析研究。运用有限元软件进行计算,提出以名义刚度作为节点抗侧力性能的评价指标,准确可靠,有效地避免了有限元计算时收敛判断不准确造成的计算终点的偏差。对不同梁高时不同加劲方式下的节点性能的比较研究表明,梁柱节点的加劲效果受梁高的影响,梁高越高,加劲效果越好。其中,同时设置竖向和横向加劲板时,在各种梁高下都表现出很好的性能,推荐使用。此研究结果可为同类工程提供参考。     

门式刚架转角节点构造设计研究

为了明确门式刚架转角节点的构造设计,对门式刚架转角节点的受力机理进一步探讨是非常必要的.通过在门式刚架转角节点处设置斜向加劲肋和无斜向加劲肋的试件进行对比和有限元分析,得出了一些有益的结论.研究结果表明,在转角节点处设置斜向加劲肋,可以提高试件的承载力.工程中,当外翼缘受拉时,建议在转角节点处设置斜向加劲肋,以防止结构失稳,并能有效地改善结构的延性.     

门式刚架转角节点加劲肋设置试验研究及有限元分析

对在门式刚架转角节点处设置斜向加劲肋和无斜向加劲肋的试件进行了试验和有限元分析,对比荷载-位移曲线,转角节点处设置斜向加劲肋的构件承载力比没有设置斜向加劲肋的构件承载力提高了约40%。研究结果表明,在转角节点处设置斜向加劲肋可以提高试件的承载力。实际工程中,当外翼缘受拉时,建议在转角节点处设置斜向加劲肋,防止结构失稳,并能有效改善结构的延性。     

空腹钢管桁架内加劲节点抗弯性能试验研究

上海市某工程中采用了内设加劲肋的箱形截面弦杆与方钢管腹杆直接焊接形成的空腹桁架节点.为考察此类节点在平面内弯矩作用下的静力承载性能,分别进行了腹杆根部有无纵肋的2个对比试件的模型试验和有限元分析.试验结果表明,该类型节点的破坏模式为腹杆根部受拉侧翼缘与弦杆连接焊缝开裂、节点域剪切变形、腹杆受压翼缘局部屈曲等形式;增设纵肋可以阻止腹杆根部受压翼缘局部屈曲的发生,并使节点域腹杆翼缘上沿杆轴方向的应力分布更均匀,但是该措施降低了节点的变形c能力.与无加劲节点承载力公式值比较结果表明,该类节点的承载力有显著提高.     

环向加劲钢筒仓在均匀内压作用下仓壁等效厚度研究

加劲肋通常作为增强筒仓仓壁强度和稳定性的措施,但目前对于如何确定筒仓加劲肋间距及尺寸的设计方法尚不明确。合理设置加劲肋,能起到提高筒仓强度承载力的作用,相当于增加了仓壁厚度。本文用数值方法研究了设置环向加劲肋的钢筒仓在均匀内压作用下的应力分布规律,提出环向加劲肋有效间距的概念,通过参数分析研究了加劲肋尺寸和筒仓几何特征对环向加劲肋有效间距的影响,提出有效间距的实用计算公式。在有效间距公式的基础上,推导出了更准确的均匀内压作用下环向加劲钢筒仓的仓壁等效厚度公式,对《粮食钢板筒仓设计规范》(GB50322-2011)中仓壁折算厚度的计算方法提出修正意见。     

具有内加劲肋的空间多支管的圆管节点性能研究

以上海旗忠网球中心可开闭屋盖的关键节点为工程背景,对主管内部具有加劲肋的空间多支管的焊接节点性能进行了试验研究和数值分析。探讨了复杂管节点试验的加载方法,描述了节点的塑性应变、破坏形式和机理以及加劲肋的构造效应。节点具有较高的承载力,主管内加劲肋的设置有效提高了节点刚度和强度,改变了节点破坏的形式。增加加劲肋的数量或者厚度有助于增强节点强度,但合理安排加劲肋的位置比增加数量更为重要,随着加劲肋数量增多,厚度的作用减弱。     

Numerical investigation of channel columns with complex stiffeners—part I: test verification

A numerical investigation on fixed-ended cold-formed steel channel columns with complex stiffeners subjected to axial load is described in this paper. The complex stiffeners of the channel sections consist of simple lips with return lips. The specimens were brake-pressed from high strength zinc-coated structural steel sheets having a nominal yield stress of 450 MPa. A non-linear finite element model is developed and verified against experimental results of fixed-ended channel columns with complex stiffeners. Initial geometric imperfections and material non-linearity are included in the model. The calibrated model is shown to provide accurate predictions of the experimental ultimate loads and failure modes of the tested columns.     

Strength of I-girders with Delta stiffeners subjected to eccentric patch loading

In this paper the effects of Delta stiffeners on strength and behavior of I-girders subjected to eccentric patch loading has been investigated. To achieve the objectives extensive computer work has been carried out using the finite element method. The beams considered here had different geometry and stiffeners arrangement. The reliability of the numerical models and results are confirmed by comparison with experimental results which show good agreement. Furthermore, the results indicate that numerical models can be used to analysis different I-girders with different stiffeners. The results also show that Delta stiffeners are more efficient than other stiffeners, especially in the case of eccentric patch loading; also the capacity of critical patch loading of I-girders increases by about 95 percent compared to the other stiffened girder.     

Experimental and Numerical Study on Complex Multi-planar Welded Tubular Joints in Umbrella-Type Space Trusses with Long Overhangs

A test rig with multi-functional purposes was specifically designed and manufactured to study the behavior of multi-planar welded tubular joints subjected to multi-planar concurrent axial loading. An experimental investigation was conducted on full-scale welded tubular joints with each consisting of one chord and eight braces under monotonic loading conditions. Two pairs or four representative specimens (two specimens for each joint type) were tested, in which each pair was reinforced with two kinds of different internal stiffeners at the intersections between the chords using welded rectangular hollow steel sections (RHSSs) and the braces using rolled circular hollow steel sections (CHSSs) and welded RHSSs. The effects of different internal stiffeners at the chord–brace intersection on the load capacity of joints under concurrent multi-planar axial compression/tension are discussed. The test results of joint strengths, failure modes, and load–stress curves are presented. Finite element analyses were performed to verify the experimental results. The study results show that the two different joint types with the internal stiffeners at the chord–brace intersection under axial compression/tension significantly increase the corresponding ultimate strength to far exceed the usual design strength. The load carrying capacity of welded tubular joints decreases with a higher degree of the manufacturing imperfection in individual braces at the tubular joints. Furthermore, the interaction effect of the concurrent axial loading applied at the welded tubular joint on member stress is apparent.     

石砌U型高桥台破坏机制及对策的模型试验研究

 针对公路建设中出现的高桥台开裂问题进行对比试验研究。设计制作4种尺寸相同的10∶1桥台模型,其中3个桥台模型采用不同构造加强形式,通过对4种桥台模型进行的填土加载和在填土表面施加外荷载,测量桥台前墙和侧墙外表面各点的水平位移进行对比分析,同时对4种高桥台模型进行三维数值计算与对比分析,得出不同构造加强形式高桥台的改进效果非常明显。试验结果表明,在桥台结构中同时采用内倒角和U型钢筋混凝土加劲构件的组合加强构造形式可以将桥台结构抵抗破坏能力提高1倍以上。     

A rational design model for transverse web stiffeners

Existing design methods for web stiffeners differ widely in concept and in the stiffener size which results. An investigation has been conducted to provide a rational, usable and validated design method for transverse stiffeners. The proposed design method takes account of the axial compression in stiffeners caused by tension field action and external forces, the transverse forces on the stiffeners required to enforce effective division of the web plate, and the tendency for the stiffened plate to buckle overall. Design criteria are established to ensure that the resulting stiffeners do not yield before plate failure, and that the plating is effectively divided into panels. The transverse stiffener dimensions required by the proposed design model have been validated against finite element results for plates subjected to pure shear, and to combined shear and direct in-plane loading. Finally, the stiffener sizes are compared with those required by the existing methods.     

Strength of tubular welded joints of roof trusses in Shanghai Qizhong Tennis Center

Static strength of multi-planar welded joints with seven brace members and one chord member made of circular hollow sections is investigated in the paper, based on the engineering practice of moveable roof trusses of Shanghai Qizhong Tennis Center. Firstly, comparative experiments were carried out on two model joints with a scale of 1:3. One joint was not reinforced, whereas the other was reinforced with ring stiffeners inside the chord member. Failure mode, stress distribution, plastic-zone development and ultimate load capacity of the joints were investigated, and effects of the ring stiffeners on the joint behavior were observed through the experiments. Secondly, finite element analysis of both the tested model joints was performed. The calculation results are in a good agreement with the experimental results, which indicated that the numerical analysis was quite effective. Finally, the strategy for enhancing strength of the complicated joint is discussed. Parameters study on the constructional details of ring stiffeners was carried out using FE method. The present research shows the multi-planar circular hollow section joint with high ratio of diameter to thickness of the chord and multiple braces is liable to chord plasticity under axial tension and compression on the braces. For the design of the joint, it is suggested that the ring stiffeners are installed insider the chord to meet needs of enough stiffness and strength. Both position and number of the stiffeners should be carefully determined based on the axial forces on the braces and their diameters. The stiffener thickness should not be less than the chord thickness, and the diameter of the hole at the center of the stiffener should not be greater than half of the chord diameter.