Comprehending the ductile behavior of slotted bolted connections

Structural steel special moment frames are designed to resist earthquakes with substantial inelastic energy dissipation. The ductile beam‐to‐column connections become more popular over these years by dissipating the earthquake input energy at beam ends. The paper provides a comprehensive study of a high‐strength slotted bolted connection (SBC). Slotted holes instead of round holes are used for the connection such that frictional sliding could be developed. Experimentally, a standard bolt–weld connection as well as three similar slotted bolted connections were designed and tested. The load‐carrying capacities, the ductile deformations, the energy dissipation capacities, and the hysteretic characteristics of the specimens were presented. The overall performance of the steel connections by replacing the circular holes with slotted holes is evaluated, and the design recommendations of the flange gusset plate with slotted holes are provided. Numerically, the nonlinear SBC behavior was simulated and calibrated against the experimental results. The SBC effectiveness as well as the parametrical influences have been presented in details. Results show that the friction slippage behaviors of the specimens with slotted holes provide better ductility, higher plastic deformation capacity, and increased load‐resisting capacities near the ultimate strength.     

三维切槽孔爆破的弹塑性数值分析

本文利用 ADINA有限元程序对三维切槽孔、圆形孔爆破作了弹塑性数值分析 ,结果表明三维切槽孔爆破的破岩半径远大于圆形孔爆破 ,为三维切槽孔爆破方法提供了数值分析依据     

Parametric finite element study on slotted rectangular and square HSS tension connections

A parametric finite element analysis study was carried out on slotted rectangular and square hollow structural section (HSS) tension connections without welding at the end of the gusset plate for different weld length ratio, slot orientation, weld size and level of HSS corner strength compared to its flat segment. Finite element models for the parametric study were developed and validated against test results of the connection with the tube slotted. The modified weld length ratio was found to be a better parameter than the modified eccentricity ratio in characterizing the net section efficiency of a slotted HSS tension member when the weld length is short. Improvements to provisions in CSA-S16-01 and ANSI/AISC-360-05 for slotted tubular tension connections were proposed based on results of the study.     

Mechanical performance of T-stub connections between square concrete filled steel tubular column and steel beam

传统的钢管混凝土柱-钢梁T形件节点易出现柱或者钢梁损伤严重的情况,不利于震后快速修复。以常规T形件和设置长槽孔T形件作为耗能构件,保证柱和梁损伤较小甚至不受损伤,实现耗能构件的可替换。对3个常规T形件节点和2个设置长槽孔T形件节点进行了数值模拟,分析了T形件翼缘厚度、T形件翼缘及腹板宽度、下T形件设置长槽孔、单边抗剪角钢等因素对节点滞回曲线、初始刚度、极限转角、延性系数、耗能能力的影响。研究结果表明：节点整体耗能较好,设置长槽孔T形件节点可显著提高节点延性,增加抗剪角钢的长槽孔T形件节点可显著提高节点耗能能力,该类节点滞回曲线呈饱满梭形,耗能表现为摩擦耗能和T形件塑性变形耗能共同作用;对于常规T形件节点,建议T形件翼缘厚度与腹板厚度的比值小于2.0。     

Design theory and numerical analysis of earthquake-resilient joint with slotted bolted connection

Bolted connections are preferred in prefabricated steel structures with the advantages of quality control and convenient construction. An innovative type of earthquake-resilient joint with slotted bolted connection (ERJ-SBC) is proposed to achieve damage control and improve the ductile behavior of steel structures. The bending moment is assumed to be mainly transferred by the flange segments of SBC while the shear force is carried by the web segments. The energy dissipation capacity of ERJ-SBC is provided by the initial frictional sliding and inelastic axial deformation of SBC under larger displacement. Design theory is proposed to ensure that inelastic deformation is concentrated in SBC while other structural members remain elastic. The influences of the length of slotted holes, bolt pretension, friction coefficient, and the thickness and width of the sliding plate are investigated through the numerical analysis of 44 FE examples. The calculation of the critical length of slotted holes for the ductile rotation behavior of ERJ-SBC is derived and verified. Results demonstrate that the mechanism of bolted connection shifts from friction resistance to bearing resistance when bolts collide with slotted holes, and the friction slippage behavior with slotted holes benefits the hysteresis behavior, deformation capacity, and rotation behavior. The proposed calculation methods for the mechanical behavior of ERJ-SBC could achieve good accuracy with simulation results. A reasonably well-designed ERJ-SBC could have good bearing capacity and rotation behavior, and it could also achieve damage control.     

管板连接轴心受拉构件极限承载力试验研究

对6个管板连接构件进行了受拉极限承载力试验研究和有限元分析。试验表明,试件的破坏均为长槽孔末端钢管横截面被拉断,其中,用板补强的试件GPT-3和GPT-6在破坏前钢管出现了明显的颈缩。分析表明,试验结果和有限元分析结果吻合良好,现行美国规范(ANSI/AISC 360-05)和加拿大规范(CAN/CSA-S16-01)中未补强的管板连接受拉承载力设计公式安全适用。研究表明,管板连接构件在受拉过程中,剪切滞后现象非常严重;长槽孔末端绕焊的焊缝质量对构件的受拉极限承载力有很大的影响。     

配置HRB500钢筋小跨高比带板开缝连梁的抗震性能试验研究

为了防止联肢剪力墙中小跨高比连梁发生低延性剪切破坏,在单连梁中部设置一条通缝,形成开缝连梁改善其抗震性能。试验完成了3个小跨高比带板开缝连梁的低周反复加载,通过与其他配筋形式连梁对比,分析了开缝连梁的破坏形态、滞回特征、承载力退化、刚度退化、延性、耗能等一系列抗震性能。利用软件ABAQUS对试件滞回曲线的骨架曲线进行模拟,并将模拟结果和试验结果相对比。结果表明,小跨高比开缝连梁具有良好的承载能力及变形能力,施工较为方便且经济,能有效防止小跨高比连梁延性较差的剪切破坏,具有较好的抗震性能,可在实际工程中推广。     

管板连接轴心受压构件极限承载力试验研究

对5个管板连接构件进行了受压极限承载力试验研究和非线性有限元分析。试验表明,未补强的试件GPC-1,GPC-3和用钢板补强的试件GPC-4,GPC-5的破坏模式均为试件的整体失稳,用焊接空心球补强的试件GPC-2的破坏模式为钢管的局部屈曲。试验结果与有限元计算结果基本吻合。实际工程中应用管板连接构件作为受压构件时,必须加强构件弱轴的刚度,以避免整体失稳破坏,而采用焊接空心球补强是一种有效的方法。     

钢框架-防屈曲开斜槽耗能钢板剪力墙装配式结构体系抗震性能分析

防屈曲开斜槽耗能钢板剪力墙(简称开斜槽钢板墙)是一种新提出的抗侧力构件,相比于普通钢板剪力墙,具有多个可调参数、耗能稳定且延性好的优点,并可作为装配式单元,通过组装单元的方式形成装配式剪力墙结构,进一步形成不同的装配式抗侧力体系。本文介绍了钢框架-开斜槽钢板墙装配式结构体系,包括开斜槽钢板墙设计方法,装配式剪力墙结构以及结构体系设计方法,并以20层办公大楼为例进行设计,对结构在小震和大震下的抗震性能进行分析。计算结果表明,开斜槽钢板墙可提供较大的抗侧刚度,能充分发挥耗能作用,保护主体结构安全,符合双重抗侧力体系的原则,该结构体系具有优越的抗震性能。     

植筋与开槽的新老混凝土结合面抗剪性能试验分析

新老混凝土能够作为整体共同工作是结构加固的关键问题。针对加固设计中经常出现植筋和开槽的技术比选问题,设计了12个试件,比较了植筋与开槽新老混凝土结合面的抗剪性能和破坏形式。试验结果表明:植筋试件破坏具有延性破坏的特征,而开槽试件破坏具有明显脆性破坏的特征,新混凝土在开槽位置被剪断;植筋试件的抗剪承载力明显高于开槽的处理方式。因此,在结构加固设计时建议采用植筋的处理方式,同时应控制植筋深度和植筋间距。     

两侧边开缝钢板剪力墙弹性屈曲分析

提出一种新型的两侧边开缝的钢板剪力墙,并对其两侧边有无加劲肋的两种结构形式进行有限元弹性屈曲分析,分别讨论其临界屈曲荷栽和屈曲模态。对两侧无加劲肋的钢板剪力墙,给出用于其设计的屈曲系数公式,对两侧有加劲肋的钢板剪力墙给出具有参考价值的设计建议。     

模型盾构隧道管片纵缝接头设计方法

考虑到拼装的缩尺模型管片环与原型管片环的纵缝接头刚度相似性难以满足要求,建议缩尺模型隧道采用开槽模型接头,并分别得到了采用两侧同时开槽、内侧开槽及外侧开槽的模型接头设计计算方法。通过开槽模型接头的管片环模型与梁—弹簧模型的计算结果比较,表明开槽模型接头的设计方法可行,开槽模型接头能很好地模拟拼装管片接头。在综合考虑开槽模型接头的开槽宽度对管片环结构内力与变形的影响与开槽模型接头的加工可行性的基础上,建议开槽模型接头对应的管片环中心角取值为3°~5°。提出的开槽模型接头设计计算理论可用于缩尺模型管片环的纵缝接头设计及在惯用法均质圆环的基础上进行局部抗弯刚度折减的数值模型隧道的建模。     

新型全长多点楔胀式管缝锚杆(竹节式锚杆)的试验研究

全长多点楔胀式管缝锚杆(竹节式锚杆)是一种作用机理及结构与普通锚杆均有所不同的新型锚杆，其锚固力由锚杆杆体与岩体的摩擦力、锚杆杆端的锚固力与多点楔胀力所提供的。对新型锚杆进行了数值模拟和物理试验，其实验室试验证实，新型锚杆的拉拔力比普通锚杆的拉拔力提高39％。结果表明，此种锚杆具有优异的力学性能、施工方便，完全可以在工程支护领域中推广应用。     

螺栓孔径与孔型对高强度螺栓摩擦型连接承载能力影响的试验

针对钢结构工程的高强度螺栓摩擦型连接中,已经出现采用大圆孔或槽型孔的情况,对不同螺栓孔径与孔型的高强度螺栓进行预拉力损失试验和抗滑移试验,以研究分析预拉力以及抗滑移系数随着孔径、孔型变化的规律.     

开长孔式叠层钢管屈曲约束支撑试验研究

设计一种开长孔式叠层钢管屈曲约束支撑,该种屈曲约束支撑采用三种不同尺寸的Q235钢管型材进行组合,并对承受轴力的芯材钢管进行开长孔削弱|通过对5个试件进行轴向低周往复加载试验,研究了不同开孔率,开孔数量对其承载力,变形性能,滞回耗能性能,骨架曲线以及破坏形态的影响。研究结果表明：此种开长孔式叠层钢管屈曲约束支撑的构造合理,在开孔率合理的情况下,支撑变形能力强,低周疲劳性能好,滞回曲线饱满,可以提供30%~42%的附加等效阻尼比。     

螺栓孔径与孔型对高强度螺栓摩擦型连接承载能力影响的试验

针对钢结构工程的高强度螺栓摩擦型连接中,已经出现采用大圆孔或槽型孔的情况,对不同螺栓孔径与孔型的高强度螺栓进行预拉力损失试验和抗滑移试验,以研究分析预拉力以及抗滑移系数随着孔径、孔型变化的规律。     

海安大厦高位结构转换层的设计与施工

为满足功能需要,海安大厦在11～12层间设计了结构转换层,12层以上采用鱼骨式剪力墙结构.转换层的ZHL-1、ZHL-2梁采用叠合梁,为增加抗剪强度,其施工缝呈齿槽形.     

Effect of concrete edge distance on the hysteretic response of roof joint

Roof joint connects the upper roof structure to the lower RC columns in large-span structures. However, during several earthquakes, concrete edge failure of roof joint observed in several previous earthquakes shows potential collapse damage of the large-span structures. This paper presents an experimental and numerical study on the performance of roof joints under quasi-static cyclic loading. The effects of concrete edge distance of anchor rods and using horizontally slotted holes in the base plate were investigated and discussed by means of ultimate shear resistances, failure modes, hysteretic responses, anchor strains, and stirrup strains. It was found that concrete edge failure was prone to occur if the edge distance was taken as per current design practice. However, with the use of slotted holes in the base plate, the concrete edge failure could be suppressed due to the sliding between the base plate and the mortar layer. A refined theoretical model was proposed to evaluate the ultimate shear resistance and predict the failure mode. Finite Element Models (FEMs) were also developed to verify the proposed theoretical model in terms of the ultimate shear resistance and the failure mode under both monotonic and cyclic loading.     

往复荷载作用下配置摩擦型阻尼器钢木混合剪力墙抗侧力性能研究

为研究配置摩擦型阻尼器钢木混合剪力墙的抗侧力性能,首先以4个摩擦型阻尼器研究了阻尼器的静力和动力特性,摩擦型阻尼器由高强螺栓穿过内、外钢板组成,钢板间夹有摩擦材料,包括无石棉有机材料NAO-780和聚四氟乙烯PTFE两种,内钢板设有长圆孔。当阻尼器激发,内、外钢板开始相对滑动耗能,当高强螺栓抵住长圆孔端部,则阻尼器锁定。阻尼器试验结果表明：阻尼器激发力与高强螺栓扭矩成线性正相关。摩擦材料NAO 780在不同加载幅值和频率下摩擦性能稳定。进而,将所研发的摩擦型阻尼器引入钢木混合剪力墙中,通过往复加载试验研究了钢木混合剪力墙的抗侧力性能。试验结果表明：阻尼器激发力越大,试件初始刚度越高,但木剪力墙损伤更严重;阻尼器内钢板长圆孔长度越长,木剪力墙可得到更多保护,但阻尼器锁定推迟,钢框架侧向变形增大。合理设置阻尼器激发力和阻尼器内钢板长圆孔长度可减小钢木混合剪力墙在地震作用下的损伤,使其在大侧移下仍有充足的抗侧能力储备,提高其抗震性能。