960 MPa高强度钢材轴压构件整体稳定性能试验研究

为研究960 MPa高强度钢材轴压构件的整体稳定性能,对6个焊接工字形和等边箱形截面试件进行了静力试验研究,测量了试件的几何初弯曲、荷载初偏心以及截面残余应力分布等初始缺陷,分析了试件的失稳破坏形态,得到了整体稳定承载力,并与规范设计曲线进行了对比分析。利用试验结果验证了有限元分析模型,并进行参数分析。研究结果表明:试件的破坏模态均为整体弯曲失稳,除两个几何初始缺陷过大的试件外,其他试件的整体稳定系数试验值均明显高于规范设计值;参数分析结果表明,960 MPa钢材焊接截面轴压构件的整体稳定系数较普通钢材显著提高,建议采用GB 50017—2003中的a类柱子曲线设计此类轴压构件,同时拟合了960 MPa高强度钢材的柱子曲线公式。     

国产Q460高强钢焊接工形柱整体稳定性能研究

为研究国产Q460高强度钢材轴压构件的整体稳定性能,对7个焊接工字形截面钢柱试件进行试验研究。试验实测了构件的几何初始缺陷和截面残余应力,并分析其失稳变形特征和整体稳定承载力。利用试验结果和实测的初始缺陷数据,验证了所建立的有限元数值模型的可靠性和准确性;此外,通过大量参数分析计算了不同截面尺寸和长度的国产Q460高强钢焊接工字形截面轴压杆绕截面强轴和弱轴失稳的整体稳定承载力,并与国内外的钢结构设计规范柱子曲线进行比较。结果表明,该类轴压杆的整体稳定系数要明显高于相应的设计曲线,即相比具有相同正则化长细比的普通强度钢材轴压杆其整体稳定系数要有明显提高;给出了建议的柱子曲线类型,并在数值分析的基础上拟合新的柱子曲线,以为工程应用和规范修订提供参考。     

Q460高强钢焊接箱形截面轴压构件整体稳定性能研究

为研究高强度钢材轴心受压钢柱的整体稳定性能,对5个国产Q460钢材焊接箱形截面柱进行了轴心受压试验研究。试验对试件的几何初弯曲、荷载初偏心以及截面的纵向残余应力分布均进行了测量。基于试验结果,分析了该类钢柱的失稳破坏形态和整体稳定承载力,建立了有限元分析模型并对试验结果进行模拟计算。研究结果表明：试件破坏模态均为整体弯曲失稳形态,大部分试件稳定承载力高于规范设计值;有限元分析模型能够准确地考虑几何初始缺陷和残余应力的影响,计算结果与试验结果吻合良好;通过与国内外钢结构设计规范的对比,提出了国产Q460高强钢焊接箱形截面轴压构件整体稳定设计的建议方法,即可以统一采用我国或欧洲规范的b类曲线进行设计,而不需要按板件宽厚比大小进行分类。     

高强钢焊接箱形轴压构件整体稳定设计方法研究

与普通强度钢材轴压构件相比,高强钢轴压构件的整体稳定承载力受构件初始缺陷,特别是受截面残余应力的影响显著降低,其整体稳定系数明显提高。国内外现行的钢结构设计规范制定的柱子曲线均是基于普通强度钢材构件的研究,现有针对高强钢轴压构件整体稳定性能的少量研究仅针对特定强度等级钢材提出了设计建议或方法。为研究不同等级高强钢轴压构件的整体稳定设计方法,全面总结了国内外现有高强钢焊接箱形截面轴压构件的试验研究,并采用三维有限元模型模拟了试件的整体稳定性能,分析过程考虑了几何初始缺陷、残余应力以及几何和材料非线性的影响。利用验证后的数值模型进行了大量参数分析,算例包括8种钢材强度等级、6种截面尺寸以及长细比不同的构件。结果表明,高强钢焊接箱形轴压构件的整体稳定性能随强度等级提高而提高。根据数值计算结果与我国钢结构规范设计曲线的对比分析,建议强度等级为Q460、Q500、Q550、Q620、Q690、Q800钢材焊接箱形轴压构件(板厚小于40mm)按b类曲线进行设计,Q890和Q960的钢材焊接箱形轴压构件(板厚小于40mm)按a类曲线进行设计。此外,还提出了更新的柱子曲线公式。     

不同等级高强钢焊接工形轴压柱整体稳定性能及设计方法研究

为研究460MPa以上不同强度等级高强钢焊接工字形截面轴压柱的整体稳定性能,采用有限元分析方法,计算了国内外已公开发表(包括其他学者)的35个高强钢焊接工形试件的整体稳定承载力,并通过与试验结果对比验证了有限元模型的可靠性;利用该模型完成1280个算例的整体稳定承载力计算,包括8种钢材强度等级、8种工字形截面尺寸、对应于每种截面的10种长细比、以及绕截面强轴和弱轴失稳的2种模态,并将算例结果与现行钢结构设计规范的设计曲线进行对比分析。研究结果表明,随着钢材强度等级的提高,高强钢焊接工字形截面轴压构件绕强轴和弱轴失稳的整体稳定系数均明显提高;对于绕强轴失稳构件,建议Q460~Q550钢材的采用我国规范b类曲线,Q620~Q960钢材的采用a类曲线;对于绕弱轴失稳构件,建议Q460~Q800钢材的按b类曲线设计,Q890和Q960钢材的按a类曲线设计。此外,还提出此类构件对应不同强度等级钢材的更新柱子曲线公式,以更准确计算其整体稳定承载力。     

国产Q460高强钢焊接T形截面轴心压杆整体稳定承载力研究

为了研究国产Q460高强钢焊接T形截面轴心压杆的整体稳定承载力,用厚度为8mm和12mm的国产Q460高强度钢板制作了3根焊接T形截面试件进行轴心受压试验。基于实测的钢材力学性能、截面残余应力和试件几何尺寸,建立考虑了初始几何缺陷和力学缺陷的有限元模型,分析预测试件的极限承载力,并将有限元结果与试验结果进行对比,验证有限元分析方法的正确性。利用经试验验证的有限元分析方法,补充计算了24根不同长细比压杆的整体稳定极限承载力,将相应的整体稳定系数与《钢结构设计标准》(GB 50017—2017)中的柱子稳定系数曲线进行比较。研究表明,国产Q460高强钢焊接T形截面轴心压杆的整体失稳形式为绕对称轴的弯扭失稳,失稳时压杆进入了弹塑性变形阶段,在设计过程中选取b类截面柱子曲线对其进行计算是安全可靠的。     

端部带约束的超高强度钢材受压构件整体稳定受力性能

高强度钢材(屈服强度≥460MPa)已经在国内外多个钢结构实际工程中得到应用,但关于其受压构件整体稳定性的研究还很少,特别是屈服强度超过690MPa的超高强度钢材。针对两种超高强度钢材S690和S960(名义屈服强度分别为690MPa和960MPa),进行了端部带约束的受压构件整体稳定受力性能的试验研究,试验共包括8个试件。基于试验结果,分析该类钢材构件的失稳破坏形态和屈曲承载力,利用经过验证的有限元模型计算其整体稳定系数,并与欧洲规范和我国规范的柱子曲线进行对比分析。结果表明,超高强度钢材受压构件整体稳定系数的试验值要明显高于其所在的b类柱子曲线,甚至比欧洲规范的a0类柱子曲线和我国规范的a类柱子曲线还要高出很多。这说明超高强度钢材受压柱的屈曲强度较普通强度钢材的屈曲强度有明显提高。这些试验研究和有限元分析成果为完善我国超高强度钢材的稳定设计方法和设计理论提供了重要的试验依据和前提条件,并有利于超高强度钢材在我国钢结构工程中得到更广泛的应用和发展。     

复合型高性能钢材轴压构件整体稳定性能研究

为提升现代钢结构工程的综合抗灾能力,集高强度、高延性、耐蚀性和耐火性为一体的新一代复合型高性能钢材已经出现。该文针对该类钢材焊接工字形截面轴压构件的整体稳定性能,设计并完成6个长柱稳定试验,研究构件的稳定承载力和失稳破坏形式,并将试验结果与我国《钢结构设计标准》(GB 50017—2017)的柱子曲线进行对比,给出建议的曲线选型;同时,建立有限元模型并验证其准确性和可靠性;进一步通过大量算例分析初始缺陷、残余应力、材料强度和本构模型等对轴压构件整体稳定性能的影响;最后,基于参数分析算例结果,拟合复合型高性能钢材轴压构件新的柱子曲线公式,提出整体稳定设计方法。研究成果对促进该类钢材的工程应用具有重要意义。     

高强度钢材轴心受压钢柱整体稳定性能的缺陷影响研究

为研究高强度钢材轴心受压构件的整体稳定受力性能,了解构件的几何初始缺陷和截面残余应力对其屈曲强度和失稳变形的影响,以及与普通强度钢材轴压杆相比高强度钢材柱的整体稳定性能对缺陷敏感性的变化,采用有限元方法进行数值模拟计算,通过变换几何初始缺陷系数、残余应力数值大小和钢材强度等参数,对计算结果进行对比分析。研究结果表明,随着钢材强度的提高,高强度钢材轴压杆的整体屈曲强度对初始缺陷的敏感性明显降低,特别是对残余应力分布的敏感性;此外,初始缺陷的影响还与构件的长细比有直接关系。研究工作进一步揭示了高强度钢材轴压柱整体稳定性能的特点和优势。     

Q690高强钢焊接箱形轴压构件整体稳定研究及设计建议

为研究Q690高强钢焊接箱形轴心受压构件的整体稳定性能,给出适合该类构件的设计建议,通过对3根Q690焊接箱形截面试件的残余应力试验,得到了箱形截面的残余应力分布模型。设计并制作了5根Q690焊接箱形柱,并对其两端铰支条件下进行了轴压试验研究,试验前分别对试件的几何初始缺陷和初始偏心均进行了测量。轴压试验中,所有试件破坏形式均为整体失稳破坏。基于试验结果,分析了该试件的整体稳定性能,采用直接分析法建立了数值模型,并校验了数值模型的准确性。同时,采用该数值模型对箱形轴压构件进行了参数分析,基于试验和参数分析结果,给出了Q690焊接箱形轴压构件的一阶弹性设计建议。     

Experimental investigation of the overall buckling behaviour of 960 MPa high strength steel columns

Investigations of the mechanical performance of high strength steel structures have become a research hotspot in civil and structural engineering, and existing experimental studies of their overall buckling behaviour have hitherto focused mainly on columns fabricated from either 460 MPa or 690 MPa steels. The present study describes an experimental programme including six pin-ended 960 MPa steel columns under axial compression. Both welded I- and box-section specimens are considered. The initial geometric imperfections and cross-sectional residual stresses are reported, with the axial loading, deformation and the strain distributions at the mid-length section being monitored during the testing. The buckling mode is clarified, and the buckling capacity is compared with design results according to current national design codes. Based on the experimental results, a finite element model is described and validated, and then used to perform a large number of parametric studies, considering different cross-sectional dimensions and column slendernesses. It is found that all specimens failed by overall flexural buckling, and the corresponding column curves in current design codes underestimate the dimensionless buckling strength of 960 MPa steel columns. Higher and more adequate column curves are suggested for such columns, and new column curves are proposed based on a non-linear fitting of the parametric results.     

960 MPa高强度钢材轴心受压构件局部稳定试验研究

针对960 MPa高强度钢材轴心受压构件的局部稳定性能,对4个箱形截面试件和4个工字形截面试件进行了轴心受压试验。分析了试件的局部稳定性能,并将试验结果与我国、美国和欧洲钢结构设计规范的相应设计计算结果进行了对比分析,研究各国规范对960 MPa高强度钢材轴心受压构件局部稳定性能设计计算的适用性。研究结果表明：当构件的板件宽厚比相同时,960 MPa高强度钢材构件的局部屈曲后强度要大于460 MPa高强度钢材构件,960 MPa高强度钢材构件应考虑钢材的屈曲后强度;我国现行钢结构设计规范中关于轴心受压构件局部屈曲应力的计算结果不适用于960 MPa高强度钢材构件;在试验钢材板件宽厚比范围内,960 MPa高强度钢材构件的局部屈曲承载力,采用美国规范和欧洲规范的设计计算结果较为准确。     

460MPa高强钢柱整体屈曲性能:试验研究及设计方法

受压柱的整体屈曲性能是钢结构研究的重要课题之一,尤其是近几年来应用越来越多的高强钢。对460MPa高强受压构件的整体屈曲性能进行试验研究。对包括焊接箱形截面和I形截面的12根钢柱进行试验。测量构件的残余应力、初弯曲和加载偏心率等初始缺陷。结合试验结果研究其屈曲变形和屈曲承载力。建立有限元模型,并与当前及以往研究中考虑初始缺陷的试验数据进行对比。采用经过验证的模型对大量不同截面尺寸和不同长度的柱的屈曲承载力进行估算,并将计算结果与其他钢结构规范的设计值进行对比。结果表明:460MPa高强钢柱,其无量纲屈曲强度与普通强度钢柱相比明显提高,并给出了相应的柱曲线和设计公式。     

Overall buckling behavior of 460 MPa high strength steel columns: Experimental investigation and design method

Overall buckling behavior of compression columns is one of the most important research subjects in steel structures, especially for high strength steel which has been increasingly applied in recent years. An experimental investigation was carried out to study the overall buckling behavior of 460 MPa high strength steel compression members. Totally twelve columns including welded box and I-sections were comprised. The initial imperfections such as the residual stress, initial bending and loading eccentricity were all measured. Based on experimental results the buckling deformation and capacity were investigated. A finite element model was established and further validated by comparing with the test data in both present study and other previous researches, in which initial imperfections were taken into account. A large number of columns with various section dimensions and lengths were calculated by using the validated model, and their buckling capacities were compared with design values according to different steel structures specifications. It was found that the nondimensional buckling strength of such 460 MPa high strength steel columns were significantly improved compared to normal strength steel columns, and corresponding column curves and design formulae were suggested.     

Tests and numerical study of ultra-high strength steel columns with end restraints

High strength steels with the nominal yield strength more than 460 MPa have begun to be applied in the construction of many steel structures, but there are short of sound researches on the major axis buckling behavior of such steel welded I-section columns, especially for the ultra-high strength steels having the nominal yield strength more than 690 MPa. In this paper, the experimental research is described on the overall buckling behavior about the major axis of ultra-high strength steel compression I-section columns with end restraints. In this research 8 columns made from 2 kinds of ultra-high strength structural steels S690 and S960, with nominal yield strengths of 690 MPa and 960 MPa, respectively, were tested. Based on the test results, the finite element analysis (FEA) model was validated to analyze this behavior of ultra-high strength steel columns, and the buckling strength of pin-ended columns fabricated from such steels were calculated by the verified FEA model, which were compared with the design buckling strengths according to the Eurocode 3, the American specification for structural steel buildings ANSI/AISC 360–05, and the Chinese codes for steel structures design GB50017-2003 respectively. It shows that the major axis nondimensional buckling strengths of the ultra-high strength steel compression columns, whose buckling curve is type b according to Eurocode 3 and GB50017-2003, are much higher than that calculated according to the column curve b, even higher than the curve a₀ in Eurocode 3 and the curve a in GB50017-2003 on average, and they are also higher than the design values according to ANSI/AISC 360–05. It is therefore indicated that the buckling strength about the major axis of the ultra-high strength steel I-section columns is improved a lot compared with the ordinary strength steel columns on a non-dimensional basis, and the column curve a₀ and curve a can be adopted to design this behavior in Eurocode 3 and GB50017-2003, respectively. Besides, there is no obvious difference between the major axis nondimensional buckling strengths of the pin-ended I-section columns fabricated from these two kinds of ultra-high strength steels: S690 and S960. These research works will provide the test basis to complete the buckling design method and theory of the ultra-high strength steel columns, and also be helpful for the application of ultra-high strength steel structures.     

高强度钢材箱形截面轴心受压短柱局部稳定试验研究

针对高强度钢材焊接箱形截面柱的局部稳定受力性能,对4个Q460钢材等边箱形短柱进行轴心受压试验。根据试验结果分析试件的局部屈曲应力、极限应力随板件宽厚比的变化规律,并将试件的局部屈曲应力、极限应力与我国、美国、欧洲钢结构设计规范以及陈绍蕃建议的相应设计方法和计算公式进行对比分析。结果表明,钢板的宽厚比越大,试件截面的利用率越低,局部屈曲后强度越富余;我国钢结构设计规范中对于试件的局部屈曲应力的计算公式不适用于等边箱形短柱;对于等边箱形短柱的极限应力,美国、欧洲钢结构设计规范和陈绍蕃建议的设计方法的计算结果较为接近,且均略高于试验结果,这3种设计方法都是可行的。进一步修改已有的计算公式,以适用于计算Q460高强度钢材等边箱形短柱的局部屈曲应力;建议采用陈绍蕃建议的设计方法,并进一步修改欧洲钢结构设计规范的计算公式,以适用于计算Q460高强度钢材等边箱形短柱的极限应力。     

超高强混凝土型钢组合长柱静力性能试验研究

为解决目前规范中缺乏超高强混凝土型钢组合柱设计方法和静力受压试验研究不够深入的问题,开展了5个轴心受压和4个偏心受压的立方体抗压强度为120 MPa超高强混凝土型钢长柱的静力试验,通过考察其破坏形态、轴力-挠度曲线、轴力-竖向位移曲线和轴力-应变曲线,研究了长细比、相对偏心距和箍筋间距对其静力性能的影响.试验结果表明:...