螺栓连接的单角钢剪切连接

介绍了19个足尺寸螺栓连接的单角钢剪切连接的试验。研究目的是确定与角钢两肢连接的螺栓组的剪切强度。试验中的连接件由两肢等长的角钢和每肢上垂直的一行螺栓构成。角钢单肢宽度为102mm,厚度为9·5mm。螺栓为直径19mm的高强度A325型螺栓,一行有2~8个。观察到的连接件破坏模式为一个螺栓组的剪切断裂。试验发现:支梁的抗扭或抗侧能力对连接件的承载能力影响很大。试验结果表明:现行的北美设计方法适用于少于或等于3个螺栓的单角钢设计。此外,采用屈服线法估算极限强度状态下的连接弯矩。     

正交胶合木墙与楼面钢梁预应力螺栓连接的抗滑移性能

正交胶合木(cross-laminated timber,CLT)-钢混合结构中,CLT剪力墙的抗侧能力主要取决于墙体与下部构件的抗剪连接.目前,角钢式抗剪连接件是工程中的主要连接形式,该类CLT墙体抗侧时,破坏往往集中在抗剪节点域,而CLT墙体受力并不大.为充分发挥CLT强度和刚度较大的优势,本文探索CLT墙与其下楼...     

高强度钢材螺栓连接抗剪性能试验研究

近年来高强度钢材在工程中得到了逐步推广和应用,尤其是Q460强度等级的高强度钢材。但是目前各国规范都尚未对高强度钢材螺栓连接设计方法做出具体规定,仍沿用普通强度钢材的设计方法。因此,需对端距、边距和螺栓间距等几何构造对高强度钢材螺栓抗剪连接性能的影响进行深入的试验研究。针对10,12 mm厚的Q460强度等级的高强度钢材进行螺栓抗剪连接试验,通过改变两个10.9级M27高强度螺栓的几何布置,研究不同端距、边距和螺栓间距情况下,高强度钢材的承压性能的变化情况。由试验可以观察到螺栓抗剪连接的3种不同的破坏模式:端部撕裂、孔壁拉长和板净截面拉断。同时还将试验得到的极限承载力与欧洲和美国钢结构设计规范设计值进行比较。结果发现,现有规范并不能很好地预测高强度钢材螺栓抗剪连接的破坏模式和极限强度,建议更深入地进行参数分析以完善规范设计方法。     

高强度螺栓咬合型连接的受拉试验研究

为研究支吊架用高强度螺栓咬合型连接的破坏机理与受拉承载力,分别进行了单个螺栓咬合型连接和典型连接的抗拉试验及有限元分析。考虑了槽钢和高强度螺栓规格等参数的影响,单个螺栓抗拉试验中共有66个试件,由六家企业提供。试验结果表明,在螺栓拉力作用下槽钢两侧卷边均绕腹板顶部棱线转动,并形成两条塑性铰线;螺栓安装扭矩对受拉承载力无影响。采用门式支架进行典型连接抗拉试验,按槽钢壁厚不同共设计6个试件。通过试验研究发现,角钢连接件对螺栓产生明显的撬力。为研究单个螺栓连接中槽钢塑性铰线长度和典型连接受拉承载力随固定螺栓间距和槽钢规格的变化情况,又对4个试件补充了有限元分析。结果表明：塑性铰线长度仅与槽钢卷边尺寸有关;角钢连接件的撬力作用能够约束卷边的竖向位移,提高卷边屈服荷载。根据试验和有限元分析结果,给出了单个螺栓连接受拉承载力设计值的计算方法,理论计算值与试验结果吻合较好。     

Resistance of flush endplate connections under tension and shear in fire

This paper presents an experimental and numerical study to the resistance of flush endplate connections in fire. Six transient fire tests were performed on two types of connections with flexible and stiff endplate. For each connection, three load combinations were tested and the test results were reported. The test shows that most connections failed within the range of 500 °C to 650 °C. Extreme bending deformation of the endplate and flexural deformation of the bolt were observed when the plate thickness was 8 mm. When the endplate thickness became 16 mm, deformations occurred to the column flange and the bolts as the endplate became thicker than the column flange. Connection fire resistances were found to decrease with increase of either tension or shear, but the connection deformations were similar regardless of the load combination within the range tested. The three-dimensional finite element simulations of the tests with flush endplate connections were conducted with general-purpose finite element program ABAQUS. The results obtained from analysis showed a good agreement with the experimental responses. Parametric study was performed to the connection failure mechanisms under an extensive range of load combinations of tension and shear in fire using the finite element model. Conclusions were drawn regarding the tension and shear interactive relationships for the two typical connections at different temperatures.     

Design moment of shear connections at the ultimate limit state

Shear connections develop moment under the rotational demand imposed on them by the supported beam. This paper proposes a semi-analytical approach for computing the moment of single-angle, double-angle and end-plate shear connections corresponding to the strength limit state of their supported beam. The connection moment equations are derived based on the observed yieldline mechanisms from various experimental tests on the shear connections. The approach takes into account major parameters such as connection plate thickness, angle length, bolt gauge and steel yield strength. The obtained equations can also be used to estimate the compression zone depth and tension zone force. Good agreement between the theoretical analysis results and the various test data is demonstrated. Finally, suggestions are given for applying the approach to design shear connections.     

Double-shear tests of high-strength structural bolts at elevated temperatures

The behavior of high-strength structural steel at elevated temperatures, especially under shear loading, is not well established in the literature. This paper presents results from recently conducted tests on high-strength structural bolts subject to double shear loading at elevated temperatures. The parameters varied between tests included the bolt grade, bolt diameter, and temperature. Bolt grades A325 and A490 were tested. For each bolt grade, three different diameters were tested (19 mm (3/4 in), 22 mm (7/8 in), and 25.4 mm (1 in)) at five different temperatures (20 °C, 200 °C, 400 °C, 500 °C, and 600 °C). At least three tests were conducted for each combination of parameters. Degradations in the mechanical and material properties including stiffness, strength, and deformation at fracture, are characterized and presented herein. The results from these experiments fill a critical knowledge gap currently present in the literature regarding the behavior of high-strength structural bolts under shear loading at elevated temperatures. These data will ultimately provide a thorough understanding of the overall behavior of structural steel systems under realistic fire loading by clarifying the (i) shear behavior of high-strength structural steel bolts at elevated temperatures, and (ii) degradation in the mechanical and material properties of high-strength steel bolts with increasing temperatures.     

钢柱脚锚栓连接受剪性能试验研究

对锚栓连接受剪性能进行试验研究,制作了5组共15个试件,考虑了锚栓的直径、柱底板厚度和底板锚栓孔径与锚栓直径之差的影响。锚栓连接受剪试验的荷载 位移曲线呈现2个转折点,可近似分为3个阶段：弹性阶段、滑移阶段和强化阶段,以锚栓基本形成塑性铰与锚栓孔壁和锚栓顶紧两个状态作为分界点。试验结果表明,柱底板厚度越大,锚栓连接受剪承载力设计值和界面抗滑移刚度越小;锚栓孔径和锚栓直径之差对滑移阶段的长度有显著的影响,对承载力影响较小。以试验荷载 位移曲线的第一转折点对应的荷载作为锚栓连接的受剪承载力设计值,提出了计算式,同时提出锚栓连接极限承载力的计算公式。     

Performance of fully encapsulated rebar bolts and D-Bolts under combined pull-and-shear loading

The performance of two types of rock bolts, fully encapsulated rebar and D-Bolt, under combined pull and shear loading were studied in the laboratory. A new test approach was developed to apply the pull and shear loads to the rock bolt at the same time so that the bolt is displaced in a direction different from the bolt axis. Five displacing angles between 0° (pure pull) and 90° (pure shear) were employed in the tests. The test results show that the linear elastic stiffness of both the D-Bolt and the rebar bolt is mobilised quickly after a small displacement. When the displacing angle is larger than 40°, grout crushing may occur underneath the bolt shank, resulting in reduction in the stiffness of the bolt. The ultimate load of the bolts remains approximately constant no matter what the displacing angle is for both the D-Bolt and the rebar bolt. The displacement capacity of the D-Bolt, however, is dependent on the displacing angle. The ultimate displacement of a 1-m long D-Bolt section varies from 140 mm under pure pull (0°) to approximately 70 mm when the displacing angle is larger than 40°. The ultimate displacement of the rebar slightly increases from 29 mm under pure pull to 53 mm under pure shear. In general, the displacement capacity of the D-Bolt is larger than that of the rebar bolt. It is approximately 3.5 times the rebar under pure pull and 50% higher than rebar under pure shear. The test results show that the displacing angle of the bolt is larger than its loading angle, which is also confirmed by the analytical solutions.     

咬合式高强螺栓连接延性破坏模式下受剪性能研究

为研究咬合式高强螺栓连接在剪力作用下的延性破坏模式和承载性能,完成了8个咬合式高强螺栓连接受剪试验。试验结果表明,当齿口个数较少时,咬合式高强螺栓连接的破坏模式为齿口屈服的延性破坏。在试验研究的基础上,建立了有限元模型并进行校验。通过8组有限元模型的参数分析发现,除改变螺栓预紧力的大小对咬合式高强螺栓连接的受剪承载力无明显影响外,齿口间摩擦系数、齿口个数、板件宽度、盖板厚度、螺栓直径、垫片厚度和弹性模量的增大均可以提高连接的受剪承载力。最后拟合得到双面受剪的咬合式高强螺栓连接的受剪承载力计算式,对比拟合计算式的计算结果、试验和数值计算结果表明,所提受剪承载力计算式合理,计算结果准确。     

火灾下采用榫钉和螺栓连接的钢木连接件的性能

重点研究火灾时平行于晶粒的拉伸荷载作用下钢木连接件扣件间的荷载分布。给出各种几何布置的不同类型连接件的试验结果。研究扣件类型(螺栓、榫钉)对连接件热力学性质的影响。采用经过试验验证的3D有限元模型,温度和失效时间的有限元分析结果与试验结果相一致。金属扣件的类型对连接件的热力学性质起着决定性的作用。研究中采用的连接件,每行扣件均使用1个螺栓,以确保其能够与安装构件分隔开来。螺栓的存在极大地影响了火灾下连接件的性能。研究了仅使用榫钉或改变螺栓位置的各种几何布置的连接件。通过改变特定连接件的一些几何特性,提出新的分析方法。数值试验设计能够用于计算连接件的破坏时间。     

腹板双角钢梁柱连接循环荷载试验研究

为了研究腹板双角钢梁柱连接的抗震性能,对四个连接试件进行了梁端循环位移加载试验。试验中考察了角钢高度、角钢与柱翼缘连接高强螺栓的直径和排列布置对连接的承载能力、滞回性能和破坏机理的影响,分析了这种连接的破坏模式和变形能力。试验结果表明:连接在循环荷载作用下表现出良好的延性,转角均超过0.04rad,连接的最终破坏均为角钢的塑性撕裂破坏;连接具有相当的抗弯能力,在结构分析中,须考虑节点抗弯强度对框架性能的影响,不能简单作为铰接处理;增大角钢的高度,能提高连接的强度;增大螺栓间距,减小螺栓直径,能提高连接的延性。最后,根据试验结果提出设计施工建议。     

GFRP板-木螺栓连接节点群组效应的受拉试验研究

木结构中多采用钢板-木螺栓连接节点,由于木材本身含水率及环境影响,会导致钢板发生腐蚀,从而给结构带来耐久性问题.文章提出采用拉挤成型玻璃纤维增强复合材料(GFRP)板替代钢板作为木结构的连接板,以提高结构耐久性,并且研究了GFRP板-木螺栓连接节点的群组效应.文章通过GFRP板-木螺栓连接节点拉伸试验,研究螺栓直径、螺...     

高强螺栓轴心抗剪连接性能分析

采用三维实体单元和接触单元,对承受轴心剪力的高强螺栓连接的性能进行研究,得出各螺栓外加拉力-螺栓剪力曲线和滑移曲线等。研究表明:各螺栓的剪力分布是中心小两头大,但并非按螺栓群中心完全对称分布;摩擦型螺栓群,剪力分布不均匀程度较大,但是在滑移发生时各螺栓分担剪力基本相等;滑移发生后螺栓群剪力分布又向不均匀发展,但是不均匀程度下降;螺栓内预拉力在外加拉力作用下会因板件泊松比效应和栓杆承压后的挤长效应发生松弛而减小。研究了螺栓间距、螺栓个数、预拉力大小、栓杆长度和板宽度对螺栓剪力的影响。     

Effect of grout properties on the pull-out load capacity of fully grouted rock bolt

This paper represents the result of a project conducted with developing a safe, practical and economical support system for engineering workings. In rock engineering, untensioned, fully cement-grouted rock bolts have been used for many years. However, there is only limited information about the action and the pull-out load capacity of rock bolts, and the relationship between bolt–grout or grout–rock and the influence of the grout properties on the pull-out load capacity of a rock bolt. The effect of grout properties on the ultimate bolt load capacity in a pull-out test has been investigated in order to evaluate the support effect of rock bolts. Approximately 80 laboratory rock bolt pull-out tests in basalt blocks have been carried out in order to explain and develop the relations between the grouting materials and untensioned, fully grouted rock bolts. The effects of the mechanical properties of grouting materials on the pull-out load capacity of a fully grouted bolt have been qualified and a number of empirical formulae have been developed for the calculating of the pull-out load capacity of the fully cement-grouted bolts on the basis of the shear strength, the uniaxial compressive strength of the grouting material, the bolt length, the bolt diameter, the bonding area and the curing time of the grouting material.     

波纹钢板纵向接缝环槽铆钉连接与高强度螺栓连接受剪性能试验研究

与高强度螺栓连接相比,环槽铆钉连接具有预紧力不易损失、耐久性好等优势,具有替代高强度螺栓用于波纹钢板纵向接缝的可行性。为便于实际工程应用,需要对其受剪性能进行研究。以波形、板厚与连接件个数为参数设计了6组36个波纹钢板纵向接缝的轴压试验,包括两组单波波纹钢板环槽铆钉连接接缝、两组四波波纹钢板环槽铆钉连接接缝以及两组四波波纹钢板高强度螺栓连接接缝。波纹钢板波形尺寸分别为150 mm×50 mm、380 mm×140 mm,板厚分别为6、7 mm和8 mm。同时考虑波形和铆钉直径的影响,对四种连接形式的32个环槽铆钉进行了预紧力试验。主要从预紧力和受剪承载力两方面对两种连接形式进行了对比,并研究了钉群效应对于环槽铆钉连接纵向接缝承载力的影响。结果表明：强度等级相同的环槽铆钉预紧力明显高于高强度螺栓预紧力,环槽铆钉接缝在试验加载过程中未出现类似于高强度螺栓接缝的预紧力损失、连接松动现象,前者具有更大的受剪承载力和更好的延性。按JGJ 99—2015《高层民用建筑钢结构技术规程》计算波纹钢板环槽铆钉连接纵向接缝承载力偏于保守。考虑钉群效应的影响,建议采用JGJ 99—2015计算孔壁承压承载力...     

Experimental study on shear capacity of corrugated steel plate-longitudinal seams with ring groove rivet connection and high strength bolt connection

与高强度螺栓连接相比，环槽铆钉连接具有预紧力不易损失、耐久性好等优势，具有替代高强度螺栓用于波纹钢板纵向接缝的可行性。为便于实际工程应用，需要对其受剪性能进行研究。以波形、板厚与连接件个数为参数设计了6组36个波纹钢板纵向接缝的轴压试验，包括两组单波波纹钢板环槽铆钉连接接缝、两组四波波纹钢板环槽铆钉连接接缝以及两组四波波纹钢板高强度螺栓连接接缝。波纹钢板波形尺寸分别为150 mm×50 mm、380 mm×140 mm，板厚分别为6、7 mm和8 mm。同时考虑波形和铆钉直径的影响，对四种连接形式的32个环槽铆钉进行了预紧力试验。主要从预紧力和受剪承载力两方面对两种连接形式进行了对比，并研究了钉群效应对于环槽铆钉连接纵向接缝承载力的影响。结果表明：强度等级相同的环槽铆钉预紧力明显高于高强度螺栓预紧力，环槽铆钉接缝在试验加载过程中未出现类似于高强度螺栓接缝的预紧力损失、连接松动现象，前者具有更大的受剪承载力和更好的延性。按JGJ 99—2015《高层民用建筑钢结构技术规程》计算波纹钢板环槽铆钉连接纵向接缝承载力偏于保守。考虑钉群效应的影响，建议采用JGJ 99—2015计算孔壁承压承载力时乘以1.4的增大系数，计算环槽铆钉受剪承载力时乘以1.1的增大系数。     

Effect of shear force on the initial stiffness of top and seat angle connections with double web angles

This study focused on the moment-rotation behavior of bolted top and seat angles with double web angle connections, especially the initial stiffness of this type of connection under the combination of shear force and moment. Several 3D parametric finite element models are presented in this regard, with the geometrical and mechanical properties of connections are as parameters. In the models, all the connection components such as beam, column, angles and bolts are modeled using eight node brick elements. The effects of all component interactions, such as slippage of bolts and frictional forces, are modeled using a surface contact algorithm, and to evaluate the connection behavior more precisely, bolt pre-tensioning is applied on the bolts shanks as the first load case. The results of numerical modeling are compared with test results of experiments that have been done by researchers, and show good agreement with them. To evaluate the effect of shear force on the behavior of such connections, several models were analyzed under different magnitudes of shear force, and the results of the analyses showed that the shear force has a reducing effect on the initial stiffness of bolted angle connections. Therefore, an equation is proposed to determine the reduction factor of a connection’s initial stiffness in terms of the connection’s initial stiffness and yield moment in the case of no shear force, and any expected shear force that might be applied.     

Tensile behavior of cruciform stubs with four bolts per row

The stiffened top-and-seat angle connection is widely used in earthquake-prone areas, and additional tensile bolts on angles' column leg effectively improve its bending behavior. However, such design and construction are not governed by any regulations. It is urgent to figure out the mechanical behavior and develop accurate theoretical methods. Based on the component method, this paper first conducted an experimental study on the extracted cruciform stubs with four bolts per row. It compared the tensile properties and damage modes for different thicknesses. After that, the further parametric analysis compared the impact of stub thickness, bolt arrangement, and whether or not the bolt was pretensioned after validation. Stub thickness and bolt gauge were observed with a greater impact than the bolt distance on the plastic resistance. Furthermore, a prediction model for the plastic resistance of the cruciform stub with four bolts per row is proposed by integrating approaches for classic stiffened and unstiffened angles.     

国产12.9级高强度螺栓力学性能试验研究

对国产12.9级高强度螺栓的工程力学性能进行全面测定,为其在建筑结构中的设计和应用以及相关标准的制定和修改提供试验依据。分别通过紧固试验、抗拉试验和剪切试验对不同品牌（A、B、C）和规格(M16、M20和M24)的各72套12.9级高强度螺栓连接副的扭矩系数、抗拉强度和剪切强度进行测定;通过抗滑移试验对72个由B品牌M20螺栓连接的、各采用3种方式处理（喷砂、抛丸和钢丝除锈）的Q235B、Q355B、Q420B连接板表面的连接接头的抗滑移系数进行测定;对5个A品牌M20螺栓制成的材性试样进行拉伸试验获得应力-应变曲线。对试验数据进行正态分布检验并根据统计结果给出12.9级高强度螺栓的扭矩系数、抗拉强度和剪切强度的设计参考值,将抗滑移系数和相关规范中给出的相应值(规范值)进行比较并分析测值较低的原因,建立螺栓材料的非线性和多折线应力-应变本构模型并验证模型精度。研究结果表明：国产12.9级高强度螺栓的扭矩系数和抗拉强度均符合性能标准,剪切强度和抗拉强度设计建议值的比值（0.49）高于二者规范值的比值（0.3）;抗滑移系数低于规范值的结果有待进一步研究,原因是接触面的粗糙度不足;非线性模型和多折线模型均能较好地拟合12.9级高强度螺栓材料的单向拉伸应力-应变曲线。