Shear buckling strength and design of curved corrugated steel webs for bridges

This paper presents the shear buckling strength and design of curved corrugated steel webs for bridges considering material inelasticity. The inelastic buckling strength is determined from buckling curves based on the proposed shear buckling parameter, which is a function of the elastic shear buckling strength of steel web and the material shear yielding strength. A finite element analysis is carried out to study the geometric parameters affecting the shear buckling strength of curved corrugated steel webs for bridges. Based on the numerical results, a shear buckling parameter formula is proposed with no need to calculate either local, global, or interactive buckling parameters. But it depends on the geometric properties of the curved corrugated web profile. Another formula is presented to maximize the shear buckling capacity of curved corrugated web. The proposed formulae agreed well with the published experimental data. The curved corrugated webs produce a tremendous increase in the shear buckling strength and considerable weight saving in regard to the corresponding trapezoidal corrugated webs. The corrugation angle has a considerable effect on the behavior of curved corrugated webs, where higher corrugation angles produce a tremendous increase in the shear buckling strength of curved corrugated webs. It was found that the proposed approach provides a good prediction for the shear buckling strength of curved corrugated steel webs of bridges.     

Shear strength and design of trapezoidally corrugated steel webs

Due to the accordion effect, corrugated steel webs are only able to resist shear force. The shear force in the web can cause three different buckling modes: local, global and interactive shear buckling. Although several researchers have been investigating it, the shear buckling behavior of the corrugated webs has not yet been clearly explained, this leads to conservative design. This paper presents the shear strength and design of trapezoidally corrugated steel webs. Firstly, global shear buckling equations are rearranged in order to derive the global shear buckling coefficient. The interactive shear buckling coefficient and the shear buckling parameter for corrugated steel webs are then proposed based on the 1st order interactive buckling equation. The inelastic buckling strength is determined from the buckling curves based on the proposed shear buckling parameter. A series of tests are conducted to verify the proposed design equations. From the test results of this study and those provided by previous researchers, it was found that the proposed shear strengths provide good predictions for the shear strength of the corrugated steel webs.     

Shear strength of trapezoidal corrugated steel webs

Corrugated webs are used to increase the shear stability of the steel webs of beams and girders and to eliminate the need for transverse stiffeners. This paper focuses on the shear strength of corrugated steel webs with trapezoidal corrugations. Previously developed formulas for predicting the shear strength of steel trapezoidal corrugated webs, along with the corresponding theory, are summarized. A new formula is developed, which considers interaction among the various shear failure modes. More than 100 test results from previous research are organized and evaluated according to relevant test specimen parameters. The conditions of many of these tests are found to be inconsistent with the theoretical conditions assumed in deriving the shear strength formulas. The various formulas for predicting shear strength are then compared with selected test results. The new formula is shown to be more accurate than previous formulas for estimating the shear strength of corrugated steel webs.     

梯形波纹钢腹板的剪切强度

波纹腹板用于提高钢梁腹板剪切稳定性,同时避免横向加劲。研究梯形波纹钢腹板的剪切强度,总结了以往梯形钢腹板的剪切强度公式及相应理论。提出新的剪切强度公式,考虑不同剪切失效模式的相互影响。根据相关试验的试件参数,对100多个试验结果进行整理和分析。大多数试验条件都与剪切强度公式中的理论条件假定不一致。将这些公式与试验进行对比,结果表明:新公式更精确。     

梯形波纹钢腹板的剪切强度

波纹腹板用于提高钢梁腹板剪切稳定性和避免横向加劲。研究梯形波纹钢腹板的剪切强度,总结了以往梯形钢腹板的剪切强度公式及相应理论。提出新的剪切强度公式,考虑不同剪切失效模式的相互影响。根据相关试验的试件参数,对100多个试验结果进行整理和分析。大多数试验条件都与剪切强度公式中的理论条件假定不一致。将这些公式计算结果与试验结果进行对比,结果表明:新公式更精确。     

Elastic interactive buckling strength of corrugated steel shear wall under pure shear force

Different ways have been presented to prevent elastic buckling of steel shear walls. One of these solutions is corrugated shear wall. In this type of wall, shear buckling strength increases without increasing the thickness of the panel. Numerical modeling results indicate that, always, shear buckling strength of corrugated panels is more than the flat panels and with the right choice of the geometric parameters of corrugated panels; without increasing the thickness of the panel, we can improve buckling strength significantly. In the trapezoidal corrugated panels, reducing the width of the subpanels do not always increase buckling strength of the panel, but it changes the panel buckling shape from the local buckling mode to the global buckling. In addition, in panels, with the low width of the subpanels, elastic buckling does not happen in the subpanels. Comparing numerical analysis with the theoretical relations showed that the results of numerical analysis with the relations that include local buckling, global buckling, and shear yielding stress, have a better approximation and in another word, interaction buckling is the combination of the local buckling, global buckling, and shear yielding stress.     

Application of corrugated plates as the web of steel coupling beams

Nowadays, steel coupling beams are used as an efficient alternative to reinforced concrete (RC) coupling beams. Particularly in the coupled shear walls system, coupling beams are the main members for dissipating seismic energy. In this paper, for the first time the application of corrugated plates as the web of steel coupling beams (rather than flat web and its stiffeners) is studied as a proposition for improving seismic behavior of such beams. The study addresses the linear elastic buckling analysis and non-linear analysis of steel coupling beams with flat and corrugated webs using finite element technique for which ANSYS software is employed. 160 models have been studied, considering parameters such as shape of web plate (flat and three corrugated types, including trapezoidal, curved, and zigzag), web thickness, number of corrugations, and corrugation angle. The finite element results are validated through comparison with the experimental results of a common steel coupling beam, tested by other researchers. In addition to the advantages of eliminating web stiffeners, results of this study show that the application of corrugated web with the proposed geometric criteria makes it possible to achieve further rotation capacity in comparison with common steel coupling beams. Finally, a design approach for corrugated web of steel coupling beams, accompanied by a practical example, is presented.     

工字梁的抗剪极限承载力

对工字梁腹板抗剪极限承载力的研究进行总结,对各种公式与文献中的试验结果进行对比,将拉力场理论和转向应力场理论的假定与ANSYS分析揭示的腹板应力发展变化规律进行对比,指出了假定和数值分析结果的不一致。提出了翼缘对腹板转动约束的合理参数,得到精度良好的考虑翼缘约束的腹板剪切屈曲系数。利用得到的屈曲系数,考虑翼缘抗弯承载力的贡献,提出新的工字梁抗剪极限承载力的计算公式。与现有试验数据和ANSYS非线性有限元分析结果的对比,证实建议方法离散性较小,适用范围广,尤其是对于通用高厚比较大的梁,较以往方法有了较大改进。     

波形钢腹板PC组合箱梁在玉春桥中的应用研究

针对一座波形钢腹板PC组合箱梁桥——玉春车行天桥,对其波形钢腹板和抗剪连接键的设计与构造进行了介绍,并对波形钢腹板和抗剪连接键的受力性能进行了计算分析,计算结果表明,在正常使用极限状态下,钢板的剪应力满足规范要求,且不会在钢板剪切屈服之前发生局部屈曲、整体屈曲或合成屈曲的破坏形式;剪力连接键的抗剪承载能力满足使用要求且具有较大的安全裕度。     

Shear capacity of connect construction between corrugated steel web and concrete lower slab

为改善波形腹板与底板连接构造混凝土浇筑质量与耐久性能,提出翼缘钢板下移至混凝土板底面,开孔板连接件垂直焊接于波形钢板并贯穿钢筋的下包型连接构造。通过设计具有不同开孔板厚度、形状及焊接宽度等参数的连接构造试件,开展标准推出试验,研究其受剪承载力、抗剪刚度、剪切破坏模式以及相对滑移特征。在试验研究的基础上,考虑钢材理想弹塑性、混凝土塑性模型以及钢-混凝土界面非线性接触,建立适用连接构造受剪分析的精细有限元模型,分析结果与试验结果吻合较好。通过验证的有限元模型进行参数分析,结果表明,增加开孔钢板的厚度和混凝土的抗压强度可有效提高受剪承载力。最后,基于模型试验与有限元参数分析结果,提出布置开孔板连接的下包型构造受剪承载力的计算式,可对开孔钢板连接面外受剪承载力进行较为准确地预测。     

单箱三室波形钢腹板悬臂梁扭转与畸变分析及试验研究

为研究单箱三室波形钢腹板箱梁悬臂状态下的扭转与畸变性能,以乌曼斯基第二理论和箱梁理论为基础,考虑了波形钢腹板的褶皱效应对箱梁纵向刚度的影响,推导了单箱三室波形钢腹板悬臂梁扭转与畸变微分方程,并采用初参数法及弹性地基梁比拟法求解了约束扭转和畸变产生的翘曲正应力和剪应力计算式。通过1片单箱三室波形钢腹板双悬臂梁进行了偏载和对称加载试验,验证了扭转与畸变翘曲应力计算公式的正确性。最后,利用推导的理论模型,分析了梁高、箱室宽度及波形钢腹板厚度等参数对偏载作用下单箱三室波形钢腹板组合箱梁截面翘曲应力的影响。研究结果表明：提出的理论计算公式可用于准确计算单箱三室波形钢腹板悬臂梁扭转与畸变效应;悬臂梁翘曲正应力主要由畸变变形引起,而约束扭转主要产生翘曲剪应力,且悬臂梁扭转和畸变产生的翘曲正应力值和剪应力值与弯曲正应力和剪应力的比值较大,因此,单箱三室波形钢腹板悬臂状态下扭转和畸变产生的翘曲正应力和剪应力不可忽略;梁高和箱室宽度对单箱三室波形钢腹板的翘曲应力影响较为显著,波形钢腹板厚度对其几乎没影响。     

预应力钢梁与波纹板的叠加效应

利用在役混凝土结构和钢结构的优点开发多种类型的组合构件,以提高结构构件的延性和适用性。混合型钢梁为类型之一,采用预应力法对该钢梁进行研究。对现有的Ⅰ形钢梁施加预应力,但是由于截面轴向刚度较大,使得预应力效果很小。另外,如果使用波纹板,由于叠加效应,加在主要抗弯构件(上、下翼缘)上的预应力会被放大,因此,这不仅对构件的适用性,而且对提高其抗弯强度都是有利的。然而,之前有关施加预应力后对波纹板钢构件的大量研究重点都放在波纹板的剪切屈曲强度上,很少涉及波纹板和梁的叠加效应。因此,本研究提出两个合理的理论模型以定量评估叠加效应,通过在波纹板钢梁中施加预应力,对2根波纹板钢梁和1根具有标准宽翼缘截面的钢梁进行了试验研究。试验结果表明,与典型板钢梁相比,波纹板钢梁的预应力效应增加得更为显著,给出的方法被证实非常简单,并与试验结果吻合较好。     

Accordion effect of prestressed steel beams with corrugated webs

Various types of composite members have been developed to utilize the combined advantages of existing reinforced concrete and steel structures, and to actively improve ductility and serviceability of structural members. One of them is the hybrid-type steel beam, in which the prestressing method is applied to a steel beam. Introducing prestress to the existing I-shaped steel beam, however, results in a very low prestress efficiency due to the large axial stiffness of the section. On the other hand, if corrugated webs are used, the prestress introduced to the main flexural-resistant elements—the upper and lower flanges—gets larger due to the accordion effect, so that it is very advantageous not only in terms of serviceability, but also of achieving the improved flexural strength. Most previous studies on steel members with corrugated webs, however, have focused on the shear buckling strength of the corrugated webs, and few studies have been conducted on the accordion effect of the corrugated webbed beam to which prestress is introduced. Therefore, this research proposed two rational and theoretical models to quantitatively estimate the accordion effect, which is induced by the introduction of prestress to corrugated webbed steel beams, and performed experiments on two steel beams with corrugated webs and one with typical wide flange section. The experimental results showed that the prestressing efficiency of steel beams with corrugated webs increased more significantly than that of the steel beam with a typical web, and it is verified that the proposed methods are very simple and provide good agreements with the experimental results.     

波形钢腹板预应力混凝土组合箱梁桥悬臂施工中钢腹板临时支撑方案比较

在悬臂施工的波形钢腹板预应力混凝土(PC)组合箱梁桥中,为了施工安全,往往需要在钢腹板上设置一些临时性支撑结构。为了克服临时支架法需占用大量施工空间的缺点,提出一种由大刚度钢管组成的钢管支架法,该方法结构简单、空间占用小。对两种方案进行比较分析,采用三维有限元数值模拟法,分别进行静力分析和特征值计算。计算结果表明:虽然临时支架在钢-混组合箱梁桥的施工中有效,但在波形钢腹板(PC)组合箱梁桥的悬臂施工过程中并不能明显改善波形钢腹板的受力状态;而钢管支架能够有效地改善悬臂状态下波形钢腹板的受力状况。     

波浪腹板工形梁局部承压承载力设计方法研究

波浪腹板工形梁的局部承压性能目前国内外研究较少。在总结前人对平腹板和梯形波折腹板梁局部承压极限承载力研究工作的基础上,对波浪腹板工形梁的局部承压性能及设计方法进行研究。通过有限元数值分析,揭示波浪腹板工形梁在局部压力作用下的破坏形式以及腹板几何初始缺陷对局部承压性能的影响,在几何参数分析的基础上建立局部承压极限承载力的简化计算公式。最后针对同时承受局部荷载和弯矩的波浪腹板工形梁,建立截面弯矩与局部压力之间的M-P承载力相关计算公式,并通过有限元数值计算进行验证。     

波形钢腹板H型截面梁抗剪性能理论研究

在前人研究波形钢腹板H型截面梁抗剪承载力成果的基础上,总结归纳了2种形式波形钢腹板在局部屈曲、整体屈曲和合成屈曲3种情况下的临界应力计算公式,通过对不同计算公式的比较提出了推荐公式.利用大量的数值计算分析,分别找出影响2种波形钢腹板H型截面梁极限抗剪承载力的因素,并得出2种不同波形钢腹板H型截面梁极限抗剪承载力计算的等效转换条件.结合前人的试验数据和本文的数值计算结果,提出了剪切稳定系数的实用计算公式.结果表明:波形钢腹板H型截面梁的波高、平子面板宽度、波幅、波长应合理设置,过大或过小都将削弱钢梁的极限承载力;提出的剪切稳定系数的实用计算公式与数值分析结果和试验数据拟合较好,并且计算简便,便于实际工程设计应用.     

Shear buckling characteristics of cold-formed steel channel beams

Cold-formed steel members are increasingly used as primary structural elements in the building industries around the world due to the availability of thin and high strength steels and advanced cold-forming technologies. Cold-formed lipped channel beams (LCB) are commonly used as flexural members such as floor joists and bearers. However, their shear capacities are determined based on conservative design rules. For the shear design of LCB web panels, their elastic shear buckling strength must be determined accurately including the potential post-buckling strength. Currently the elastic shear buckling coefficients of LCB web panels are determined by assuming conservatively that the web panels are simply supported at the junction between their flange and web elements. Hence finite element analyses were conducted to investigate the elastic shear buckling behavior of LCBs. An improved equation for the higher elastic shear buckling coefficient of LCBs was proposed based on finite element analysis results and included in the ultimate shear capacity equations of the North American cold-formed steel codes. Finite element analyses show that relatively short span LCBs without flange restraints are subjected to a new combined shear and flange distortion action due to the unbalanced shear flow. They also show that significant post-buckling strength is available for LCBs subjected to shear. New equations were also proposed in which post-buckling strength of LCBs was included.     

考虑腹板剪切变形的波形钢腹板组合箱梁剪力滞效应分析

在波形钢腹板组合箱梁中,剪力主要由波形钢腹板承担。由于波形钢腹板的抗剪刚度比混凝土腹板有较大程度的降低,波形钢腹板会产生较大的竖向剪切变形。为此,基于能量变分法建立了考虑腹板剪切变形的波形钢腹板组合箱梁剪力滞效应分析方法。通过试验对该理论分析方法进行验证,并基于该理论分析方法研究波形钢腹板剪切变形对剪力滞效应的影响。同时,基于该分析方法提出了采用影响线最不利加载方式进行相关规范中规定的汽车荷载作用下的波形钢腹板组合箱梁桥剪力滞效应分析。结果表明：考虑腹板剪切变形的分析方法与试验结果吻合度良好;波形钢腹板的剪切变形有利于减轻三跨连续梁正弯矩区的剪力滞效应,即考虑腹板剪切变形后翼缘有效宽度系数值更接近于1。     

波纹腹板焊接H形钢疲劳性能试验研究

设计了4根梯形波纹腹板焊接H形钢试件,依据GB 50017-2003《钢结构设计规范》的相关规定进行疲劳性能试验,并特别考虑了GB 50278-2010 《起重设备安装工程施工及验收规范》中吊车梁安装偏差的相关规定。通过ANSYS有限元分析验证试件破坏形式的合理性。研究结果表明：对于CECS 291:2011 《波纹腹板钢结构技术规程》中推荐波形的梯形波纹腹板H形钢,其疲劳性能优于平腹板H形钢,疲劳设计中可按3类钢构件进行计算,且不考虑腹板波纹转折引起的应力集中及安装偏差等施工因素的影响。     

部分混凝土外包波形钢腹板组合工字梁的抗剪性能试验研究

针对提高负弯矩作用下连续梁的结构特性提出了一种新型的部分混凝土外包波形钢腹板组合工字梁。对这种混凝土外包组合工字梁在对抗荷载下的抗剪性能进行试验分析研究。试验结果显示与普通的工字梁相比,混凝土外包组合工字梁的剪切屈曲因受外包混凝土的限制而有了更好的抗剪强度。由于组合截面的抗剪刚度是基于波形钢腹板和破裂前外包混凝土平均厚度的总和,且其抗剪强度决定了由钢腹板和外包混凝土共享的抗剪强度比。此外,根据试验中的破坏模式和应变分布,提出部分混凝土外包波形钢腹板组合工字梁的预估抗剪强度。试验结果验证了之前分析得出的弹性阶段的抗剪刚度和抗剪比。且之前计算得出的钢腹板与组合梁的抗剪强度也与试验结果一致。通过对比可知文中提到的分析方法可以应用到部分混凝土外包波形钢腹板组合工字梁结构的抗剪刚度预估和抗剪强度设计中去。