Structural Resistance of SRC Column-Steel Beam Joint Developed for Innovative Construction of Buildings

This paper presents an experimental study investigating factors influencing the effective width of steel reinforced concrete (SRC) column-steel beam joints of building in order to calculate its resisting moment.Five 1/2 scaled interior SRC column-steel beam joint specimens were made with considering parameters such as beam flange width,beam depth and SRC column width.One directional increasing moment was applied to the joint by acting forces to each ends of beam and the structural behavior of joint was studied.And previous design method suggested by Deierlein was reviewed and a modified equation was proposed from the analysis of test result.Test result indicated that the equation to calculate the effective width in Deierlein’s design method didn’t consider effectively the influence caused by the variation of beam depth so that a modified equation was suggested and the validation of it was confirmed in this paper.

Seismic Behaviour of Beam-Column Joints of Precast and Partial Steel Reinforced Concrete

A beam-column joint of precast and partial steel reinforced concrete( PPSRC) is proposed for precast reinforced concrete frames. The PPSRC consists of partial steel and reinforced concrete. The partial steel is located in the core joint region and the connections between concrete members. This paper presents an experimental study of a series of PPSRC specimens. These specimens are tested under low cyclic loading.Experimental results demonstrate that the bearing capacity of the PPSRC specimens is 3 times that of the ordinary reinforced concrete( RC) beam-column joints. The strength and stiffness degradation rates are slower compared with that of the RC beam-column joints. In addition,the strength of the core joint region and the connections is higher than other parts of the PPSRC specimens. Beam failure occurs firstly for the PPSRC specimens,followed by column failure and connections failure. The failure of the core joint region occurs finally.Test results show that the seismic performance of the PPSRC is better than that of the ordinary RC beam-column joints.

Static behavior of semi-rigid thin-walled steel-concrete composite beam-to-column joints with bolted partial-depth flush end plate:experimental study

A new type of semi-rigid thin-walled steel-concrete composite beam-to-column joint has been proposed in this paper.Five semi-rigid composite beam-to-column joint specimens subjected to hogging moments under monotonic loading were tested to study the static behavior of this new type of joint.The main variable parameters for the five joint specimens were the longitudinal reinforcement ratio and the joint type.The experimental results designated that the magnitude of extension of the longitudinal reinforcement is the most important factor that influenced the moment-rotation characteristic of the new type of joint.The concrete slabs could resist 3.8%-19.1% of the total shear load applied to the cross-sections near the beam-to-column connection.The edge stiffened elements,such as the flange of the lipped I-section thin-walled steel beam,were capable of having considerable inelastic deformation capacity although they had comparatively large width-to-thickness ratios.The shear failure of the concrete cantilever edge strip must be taken into account in practical design because it has significant influence on the anchorage of the longitudinal reinforcement in the new type of external joints.

Flexural Capacity Formula of Diaphragm-Through Joints of Concrete-Filled Square Steel Tubular Columns

Finite element analysis and parametric studies were performed to investigate the flexural capacity of the panel zone of diaphragm-through joints between concrete-filled square steel tubular columns and H-shaped steel beams. Through the comparisons of failure modes, load–displacement curves, and bearing capacity, it was found that the flexural capacity of the panel zone of diaphragm-through joints was determined by the tensile action and influence of the web of H-shaped steel beams, and the axial load should be taken into account. The steel tube and the diaphragm were the major parts of the joint that resisted the bending moment. The contribution of in-filled concrete had little influence on the flexural capacity of the panel zone of the joint and could be neglected. According to the results of these numerical studies, a formula that considered the influence of the web of H-shaped steel beams and the axial load was developed based on the yield lines in the diaphragm and the steel tube. The results of the proposed formula were in good agreement with the numerical data of this investigation. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

Seismic performance of steel reinforced ultra high-strength concrete composite frame joints

To investigate the seismic performance of a composite frame comprised of steel reinforced ultra high-strength concrete （SRUHSC） columns and steel reinforced concrete （SRC） beams, six interior frame joint specimens were designed and tested under low cyclically lateral load. The effects of the axial load ratio and volumetric stirrup ratio were studied on the characteristics of the frame joint performance including crack pattern, failure mode, ductility, energy dissipation capacity, strength degradation and rigidity degradation. It was found that all joint specimens behaved in a ductile manner with flexural-shear failure in the joint core region while plastic hinges appeared at the beam ends. The ductility and energy absorption capacity of joints increased as the axial load ratio decreased and the volumetric stirIup ratio increased. The displacement ductility coefficient and equivalent damping coefficient of the joints fell between the corresponding coefficients of the steel reinforced concrete （SRC） frame joint and RC frame joint. The axial load ratio and volumetric stirrup ratio have less influence on the strength degradation and more influence on the stiffness degradation. The stiffness of the joint degrades more significantly for a low volumetric stirrup ratio and high axial load ratio. The characteristics obtained from the SRUHSC composite frame joint specimens with better seismic performance may be a useful reference in future engineering applications.

装配式钢结构梁柱连接节点研究进展

装配式建筑既是建筑现代设计理念、构件生产、现场管理革新的重要途径,也是推行组件化理念和智能化转型的重要举措。结合目前国内装配式钢结构梁柱连接节点研究情况,对可恢复式梁柱节点、方钢管柱-桁架梁、带悬臂梁节点、框架体系装配式节点形式的构造和力学性能进行阐述与总结。研究表明,装配式钢结构梁柱具有良好的承载力、延性和抗震性能,但是目前基于装配式节点构造及各参数的研究主要针对二维平面,一定程度上制约了其应用和发展,后续需对节点在火灾作用下的破坏及损伤时序、三维空间结构中楼板与梁柱节点的连接方式和考虑楼板后整体结构的复位机理与刚度变化历程进行进一步研究,为增加新材料、新工艺的应用,推广至实际工程提供理论依据。

新型钢管混凝土梁柱节点力学性能试验研究

为研究内加强环式圆钢管混凝土柱与矩形钢管混凝土梁这种新型连接节点的力学性能,设计了缩尺钢管混凝土梁柱节点试件,开展了相同梁柱节点试件的静力加载试验和低周往复加载试验。通过研究该节点试件的破坏模式、荷载-位移曲线以及拟静力加载试验的骨架曲线、核心区剪切变形等,分析了节点试件的承载能力、延性和耗能能力,全面考察了同一梁柱节点在静力加载和低周往复加载两种工况下的受力性能和破坏模式。结果表明:钢管混凝土梁柱节点试件核心区强度较强,破坏模式主要为梁端破坏,低周往复加载试验时试件梁柱连接处附近的梁端钢板发生拉裂破坏和钢板鼓曲,静力加载试验时试件梁端焊缝发生拉裂破坏;试件延性较好,加载过程中经历了弹性、弹塑性和塑性发展阶段。最后提出了该类钢管混凝土梁柱节点核心区的抗剪强度计算公式。

开槽侧板加强型连接梁柱节点子结构抗连续倒塌性能研究

为了优化侧板加强型节点的抗连续倒塌性能,提出了一种开槽侧板加强型梁柱连接节点形式。通过静力加载试验,得到了新型节点子结构的破坏模式、竖向抗力发展机制、应变分布、延性水平和动力承载力等。试验结果表明:钢梁翼缘在盖板附近首先开裂并向腹板外排螺栓中部延伸贯穿,导致竖向承载力快速下降为峰值荷载的20%左右。相比传统侧板加强型和圆弧扩盖板型梁柱节点,新型节点的峰值承载力分别提高了62.1%和19.6%,塑性弦转角分别提高了203.6%和25.8%。通过有限元分析得到了试件的断裂路径发展过程,进一步地通过参数化分析发现:扩大过焊孔构造对改善峰值后塑性弦转角及残余强度提升无明显作用;随着螺栓群远离钢梁翼缘起始断裂位置,最小残余强度比不断增大,但峰值后塑性弦转角呈先增大后减小的趋势;当螺栓群内移45mm时,峰值后塑性弦转角及最小残余强度比分别达到0.149rad和0.88,提高了38.2%和200.8%。

横向贯通式中低速磁浮一体轨道梁钢-混结合部试验研究

为解决中低速磁浮分离式轨道梁存在的养护难、构件多,以及无法考虑F轨刚度贡献等问题,提出一种横向贯通式梁轨一体轨道梁结构,针对其钢-混结合部的静力性能开展有限元分析和足尺模型试验研究,并对关键设计参数进行参数分析。结果表明,在5倍设计荷载内,钢-混结合部基本处于弹性状态,承载力满足设计要求,且具备较高富裕量;竖向荷载主要通过钢板承压作用传递至混凝土梁体,焊钉对竖向荷载的传递作用较小;设计参数分析表明,适量提高钢连接件钢板厚度有利于竖向荷载的平顺传递。研究结果可以为梁轨一体轨道梁设计提供参考。

配筋PVA-钢混杂纤维增强水泥基复合材料梁柱边节点抗震性能试验研究

改善工程材料韧性和耐久性,提高框架梁柱节点抵抗变形和破坏的能力,是提高框架结构抗震韧性的有效途径之一。采用PVA-钢混杂纤维增强水泥基复合材料代替普通混凝土应用到梁柱边节点,考虑轴压比和加密区体积配箍率的影响,设计6个配筋PVA-钢混杂纤维增强水泥基复合材料、1个配筋单掺PVA纤维增强水泥基复合材料和1个钢筋混凝土梁柱边节点试件进行拟静力试验,分析其破坏形态、滞回曲线、骨架曲线、延性、耗能能力、钢筋应变和梁端塑性铰区转角,探讨混杂纤维的加入对梁柱边节点抗震性能的影响。结果表明:与钢筋混凝土节点和单掺PVA纤维增强水泥基复合材料节点相比,PVA-钢混杂纤维增强水泥基复合材料节点的承载力高、变形能力大、延性好、耗能能力强,抗震性能显著提升。当试验轴压比从0.12增加到0.24,梁端塑性铰区产生一定的外移,塑性性能发挥更充分,同时试件的变形能力、延性、耗能能力增加。在加密区体积配箍率减小的情况下,试件仍表现出良好的抗震性能。

钢管混凝土柱-钢梁连接节点形式与研究进展

钢管混凝土结构体系中,梁柱节点的受力状态复杂,是结构体系中的关键连接部位,对结构的承载力、刚度以及稳定性能均有重要影响。对国内外钢管混凝土柱-钢梁连接节点的相关研究进行了全面的综述,总结了内加强型连接节点、外加强型连接节点、贯通式连接节点、螺栓连接节点等各类钢管混凝土柱-钢梁连接节点形式的特点和已有研究,从承载力、刚度、破坏模式、抗震性能、设计方法等方面对各类连接节点的优势和存在的问题进行了分析和归纳。旨在为钢管混凝土柱-钢梁连接节点的相关研究提供参考,促进钢管混凝土柱结构体系的研究和工程应用。

钢梁贯通型装配式混凝土框架梁柱节点恢复力模型研究

为研究装配式混凝土干连接节点在地震作用下的动力特性,文章设计制作了6个新型装配式节点,通过改变面承板厚度、钢环箍厚度、面承板宽度和钢梁翼缘厚度进行试验,研究不同变量对节点抗震性能的影响。基于试验结果及加载过程中的试验现象,结合三折线模型对数据进行处理,拟合出计算骨架曲线,并在此基础上,结合滞回规则拟合出计算滞回曲线。将拟合所得计算骨架曲线和计算滞回曲线与试验所得曲线进行对比,吻合度均较好。结果表明:根据三折线模型拟合出的计算骨架曲线可以较好地反映该节点的受力特征;根据滞回规则得到的计算滞回曲线可以有效反映该节点的滞回性能。该恢复力模型可为该类装配式节点的抗震性能分析提供参考。

嵌入式H型钢梁柱节点受力性能研究

为解决传统标准梁柱节点施工复杂、节点强度低等一系列问题,提出一种嵌入式H型钢梁柱节点结构形式,并设计4个梁柱节点试件(1个标准现浇梁柱节点试件,3个嵌入式H型钢梁柱节点试件)进行试验研究,设置型钢翼缘宽度、剪跨比为主要参数,对4个试件的破坏形态、承载力、变形能力进行对比分析。结果表明:嵌入式H型钢梁柱节点试件的节点核心区柱端混凝土裂缝较少,裂缝分布和破坏位置基本上发生于梁端,充分满足了“强柱弱梁”的设计要求;相较于标准现浇梁柱节点试件,嵌入式H型钢梁柱节点试件峰值承载力、极限承载力、变形能力均显著提高,当型钢翼缘加宽时,试件峰值承载力和极限承载力提升较为有限,当剪跨比大于2.7时,承载力将会明显降低。

装配式建筑组合梁端预埋槽钢节点静力性能仿真研究

为分析装配式组合梁端预埋槽钢节点的静力性能,文中通过静力试验,模拟分析预埋槽钢节点的破坏模式、承载力、刚度及应变变化规律。结果表明,当槽钢厚度从100 mm增加至300 mm时,试件最大弯矩值提升201.9%,初始刚度提升92.9%;当槽钢预埋深度降低、箍筋间距降低、增设跨中空腔、槽钢无偏心距、槽钢厚度降低时,最大弯矩降低;当槽钢预埋深度增加、箍筋间距降低、无跨中空腔、槽钢存在偏心距、槽钢厚度增加时,试件初始刚度增加。装配式组合梁预埋槽钢节点刚度随着腹板厚度的降低而降低。

装配式混凝土剪力墙-梁钢套筒节点性能试验研究

为研究螺栓连接的装配式剪力墙-梁节点的抗震性能,提出了一种在剪力墙内预埋高强螺杆,然后通过钢端板与混凝土梁连接的节点,设计了3组缩尺装配式试件与1组缩尺现浇试件,并对其进行了拟静力试验,研究分析了节点的破坏形态、滞回曲线、骨架曲线、刚度退化、耗能能力等。结果表明:3组装配式试件的滞回曲线呈“弓形”,且装配式试件的峰值承载力比现浇试件提升了8.42%~21.05%,位移延性系数在4.28~4.66之间,等效黏滞阻尼系数均在0.18~0.24之间,证明了该装配式节点具有良好的抗震能力和变形能力。

焊接空心球连接H型钢Z字形螺栓节点静力性能研究

提出了一种新型焊接空心球连接H型钢Z字形螺栓节点(新型螺栓节点),该节点适用于全装配大跨度弦支穹顶结构体系上部网壳连接。该节点的弦杆采用热轧H型钢,方便栓接、施工便捷、制造能耗低,可以实现部品部件到体系的标准化。为了研究新型螺栓节点的静力性能,对该节点进行了轴压、轴拉、纯弯和压弯荷载工况下的有限元分析,研究了该节点在不同荷载工况下的破坏模式、承载力、刚度、延性等力学性能指标,对比分析了新型螺栓节点与焊接空心球连接H型钢焊接节点(焊接节点)的破坏模式和静力性能。研究表明,在轴压和压弯荷载下新型螺栓节点和焊接节点的极限破坏模式均为H型钢弦杆局部屈曲和屈服,在轴拉荷载下新型螺栓节点和焊接节点的极限破坏模式均为H型钢弦杆全截面屈服,在纯弯荷载下新型螺栓节点和焊接节点的极限破坏模式均为H型钢弦杆局部屈曲。新型螺栓节点可以实现塑性铰远离焊缝和拼接区,符合“强连接,弱杆件”的设计要求。

预应力混凝土梁-型钢混凝土柱新型框架节点受剪承载力计算方法

梁柱节点受剪承载力计算是混凝土框架结构节点抗震设计的关键点之一,由于节点剪力传递机理与构造的复杂性,目前尚未形成完善的节点受剪承载力计算理论。该文阐述了预应力混凝土梁-型钢混凝土柱新型框架节点的受力机理,并基于桁架模型和斜压杆模型,提出了一种同时考虑预应力筋与型钢贡献的节点受剪承载力计算方法。开展了新型节点受力性能拟静力试验,分别选取了梁端破坏与节点剪切破坏两种破坏形式的节点试验数据,对所建立的新型节点受剪承载力计算方法进行了验证评估,结果表明,该文提出的预应力混凝土梁-型钢混凝土柱框架节点承载力计算方法具有较好的精度。

整体式组合梁桥梁台结合部模型试验研究

整体式桥台桥梁免除了伸缩缝的建造费用以及病害和更换问题。为研究整体式钢-混组合梁桥梁台结合部力学性能,本文提出压剪式,腹板式和插入式3种结合部构造形式,进行静力加载模型试验,考虑弯矩最不利和剪力最不利2种工况,对结合部位移和相对滑移数据进行测试。模型试验结果表明:压剪式试件承载力最大,相对转动刚度最大,荷载位移关系和弯矩转角关系线性段最长,结合性能最优。研究结果可为整体式组合梁桥梁台结合部的设计和研究提供参考和借鉴。

翼缘连接板削弱型上焊下栓钢梁柱节点抗震性能有限元分析

分析不同参数对节点抗震性能的影响,为梁柱翼缘连接板削弱型上焊下栓钢结构梁柱节点的设计提供参考。通过改变下翼缘连接板削弱区长度和框架梁截面形状,设计7组算例,利用有限元软件ABAQUS对翼缘连接板削弱型上焊下栓钢梁柱节点进行有限元分析,研究其破坏模式、滞回曲线、骨架曲线、最大承载力和螺栓孔径变化率。有限元分析结果表明:下翼缘连接板削弱长度过短无法达到塑性铰外移的目的,削弱长度过长则会导致严重的平面外屈曲;梁全截面削弱组的抗震性能优于半截面削弱组与无变化组。翼缘连接板削弱型上焊下栓钢梁柱节点能有效利用翼缘连接板削弱区的塑性变形、拼接区螺栓的滑移、螺栓杆与孔壁的挤压,以及板件的摩擦来实现耗能。

轴压比和面承板厚度对混合节点抗震性能的影响

为了研究新型柱全截面隔板式钢筋混凝土柱-钢梁(RCS)混合框架节点形式的抗震性能,考虑不同轴压比和面承板厚度的影响,对2组共6个3/4比例的梁柱节点进行低周往复加载试验研究.试验中所有试件均发生设计预期的节点剪切破坏,滞回曲线呈弓型,表明节点具有良好的抗震性能.试件最终因节点区的混凝土开裂剥落而丧失承载力.试验结果表明,当轴压比为0~0.25时,随着轴压比的增大,RCS节点开裂荷载有所增大,峰值荷载前斜裂缝数量减少、宽度减小,试件的承载力、刚度和耗能能力均有所提高.节点域柱纵筋黏结应力随轴压比增大而减小,表明节点域内黏结状况有明显改善.相较于单向面承板试件,双向面承板试件在承载能力、延性和耗能能力方面均表现出显著提高;当双向面承板厚度由6 mm增加至10 mm时,试件峰值承载力和刚度的提升幅度相对有限.