圆形钢筋混凝土桥墩等效塑性铰长度

基于桥墩极限位移三分量模型,从弯曲、剪切和纵筋滑移变形等三方面分析了桥墩塑性铰长度的主要影响参数;通过40个圆形钢筋混凝土桥墩试验数据的分析,建议了桥墩塑性铰长度的理论公式及经验公式;并对建议及各规范的塑性铰长度公式进行了模型桥墩、足尺桥墩和实桥桥墩的验证。结果表明：钢筋混凝土桥墩塑性铰长度主要随墩高、截面高度、材料特性参数（fydb/fc′）及纵筋率的增大而增大,与轴压比、配箍率等关系不大;与试验结果相比,就平均意义而言,各国规范塑性铰长度计算结果偏于安全,但均有较大的离散性,日本JRA规范最为保守,中国《公路桥梁抗震设计细则》（JTG/T B02-01—2008）较美国Caltrans规范及欧洲Eurocode8规范保守;建议的塑性铰长度理论公式与日本JRA规范相当,建议的塑性铰长度经验公式在平均意义上与美国Caltrans规范及欧洲Eurocode8规范一致,但具有较小的变异系数和较高的保证率,优于其他公式。     

高强钢筋高强混凝土桥墩等效塑性铰区长度分析

钢筋与混凝土材料的高强化是工程结构发展的重要方向,为研究配置高强钢筋的高强混凝土桥墩等效塑性铰区长度,整理了37根高强钢筋高强混凝土桥墩试验数据,与Priestley、Paulay、Telemachos及我国《公路桥梁抗震设计细则》建议的塑性铰区长度计算公式进行了对比分析,并通过灰色关联方法分析了影响高强钢筋高强混凝土...     

延性桥墩塑性铰区最低约束箍筋用量

依据 3次不同试验的研究成果和非线性回归分析 ,建立了计算延性桥墩塑性铰区范围最低约束箍筋用量的计算公式 ,并与公路工程抗震设计规范 (JTJ 0 0 4 - 89)有关规定和国外规范计算公式进行了比较。本文所建立的计算公式 ,可供新修订的桥梁抗震设计规范参考采用     

钢筋混凝土桥墩塑性损伤试验研究

对4种不同配筋率和配箍形式的大尺寸钢筋混凝土桥墩进行低周反复试验。结果显示:不同损伤阶段对滞回曲线、耗能能力以及承载力的影响不同。混凝土保护层剥落、纵向钢筋的压屈可以作为各桥墩承载力下降和耗能能力下降的特征现象。对比构件的保护层混凝土剥落范围以及塑性曲率分布范围,提出等效塑性铰长度的建议式。     

框架结构梁中塑性铰设置的探讨

该文运用有关塑性实验结果、并结合我国现行规范分析了梁中塑性铰如何设置，以及阐述了塑性铰移位后梁、柱节点如何正确设计的问题。     

无粘结预应力混凝土梁塑性铰的研究

在总结配筋混凝土受弯构件等效塑性铰研究现状的基础上,通过对无粘结预应力混凝土梁的仿真模拟试验和理论分析,建立了适于无粘结预应力混凝土受弯构件的等效塑性铰长度计算公式,为无粘结预应力混凝土结构的塑性设计方法研究提供了参考依据。     

矩形钢管混凝土框架的塑性铰长度研究

为了研究矩形钢管混凝土框架的抗震性能和塑性铰长度,对四榀由方钢管混凝土柱-矩形钢管混凝土梁组成的单层单跨钢管混凝土框架结构进行了拟静力试验研究和非线性有限元分析,得到了该类框架的破坏模式、框架梁柱塑性铰的长度范围及其发生规律。研究结果表明:所有矩形钢管混凝土框架均表现出"强柱弱梁"的破坏机制,滞回曲线为较饱满的梭形,具有良好的延性性能;梁、柱端塑性铰中心出现在距离环板和加劲肋h/4~h/2的位置,塑性铰长度约为100mm。对试验研究、理论分析和数值模拟得到的塑性铰长度进行了对比,结果吻合较好,说明选用的塑性铰长度计算方法适用于矩形钢管混凝土框架。     

钢骨混凝土框架节点塑性铰研究

针对按常规设计的钢骨混凝土框架节点在受力性能试验中大变形阶段出现节点核心区破坏的情况,提出采用狗骨节点的方法,将塑性铰位置控制在梁端,保护节点核心区,为实际工程应用提供了技术支持。     

动荷载作用于钢管混凝土构件形成塑性铰的研究

钢管混凝土构件在侧向动荷载作用下产生塑性变形,从而使能量消耗在塑性铰中.利用有限元程序ANSYS/DYNA,验证了模型的正确性,分析并拓延了塑性铰的有关性质,以便在抗震设计中加以有效利用.     

框架结构的塑性铰及塑性铰设计

钢筋混凝土框架结构的承载能力比砌体结构高。而且具有很好的延性和整体性，特别是抗震性能良好，所以应用非常广泛。抗震设计就是要发挥和保证钢筋混凝土多层框架结构这种独特的可贵性质。     

矩形截面混凝土空心墩塑性铰长度分析

在延性抗震设计中,等效塑性铰长度直接影响到桥墩位移能力的估算,其计算的准确性对于桥墩抗震性能的评估至关重要。现有规范中等效塑性铰长度公式大多是由实心墩试验得到的,鉴于空心墩与实心墩的性能差异,这些公式对空心墩的适用性尚有待深入研究。通过7个不同设计参数的矩形截面空心墩拟静力试验,观测并分析不同构件塑性铰区损伤演化及变化趋势,研究剪跨比、纵筋率、配箍率对墩底塑性铰分布形态的影响。基于国内外等效塑性铰长度计算公式与试验结果的对比分析,发现：塑性铰长度随墩身计算长度的增大而增大,配箍率、纵筋配筋率对其有一定影响;在现有规范及文献中,Telemachos、Eurocode8、高振世的塑性铰长度计算值与实测值较为接近,适于估算矩形空心墩的塑性变形能力。     

刚架结构极限承载力分析的广义塑性铰研究

传统塑性铰法及其改进方法具备比例特点,能够根据外荷载与内力之间的比例关系快捷确定刚架的塑性铰位置和极限承载力,但不能应用于多内力组合作用下的刚架极限承载力问题。随后发展起来的二阶塑性铰法和精细塑性铰法尽管解决了该问题,但不具备比例特点,需通过大量迭代试算、并连续调整荷载增量来确定刚架的塑性铰位置和极限承载力,导致理论复杂,计算效率低。为此,文章利用广义屈服准则提出内力组合因子的定义,据此建立具备比例特点的广义塑性铰法,能够快捷处理刚架结构在多内力组合作用下的极限承载力问题。首先,利用广义屈服准则研究建立内力组合因子,据此修正刚架单元在不同加载步的截面强度。然后,利用齐次广义屈服函数和标准化内力定义单元承载比,并根据荷载与单元承载比之间的比例关系快捷确定各加载步的塑性铰位置和极限承载力。最后,通过与弹塑性增量法和改进塑性铰法对比分析,验证了该方法具有简捷、高效和高精度特性。     

关于磨擦铰链在塑料平开窗的应用

塑料平开窗具有良好的气密及保温、隔热性能,目前广泛应用;而磨擦铰链因其良好的随意定位、安全性及成本优势也被越来多客户选用。但是笔者就目前型材的情况和磨擦铰链的安装应用提出一些看法,欢迎行业同仁指正。     

Seismic behavior of wide-flange steel column with confined potential plastic hinge

This experimental project investigates and validates an innovative method to confine the potential plastic hinge zone of hot-rolled H-shape (or wide-flange) steel column for improved seismic behavior. Based on fundamental mechanics, the concept aims at controlling the local buckling of the flange and web elements of the H-shape steel in the potential plastic hinge region of a column. In the experimental program, six model columns were tested under constant axial load and cyclic lateral forces acting in either the weak or the strong axes. Compared with the conventional H-shape steel model columns, the model columns with their potential plastic hinge zone confined by either steel strips or reinforced concrete cover, exhibited excellent seismic performance with large ductility. Analytical efforts to compare with the test results were also made using simple moment-curvature analysis.     

Quasi-static cyclic tests and plastic hinge analysis of RC structural walls

This paper presents the results of quasi-static cyclic tests on six reinforced concrete (RC) walls performed at the ETH Zurich. These large-scale tests investigate the effect of different vertical reinforcement contents and different reinforcement ductility properties typical for Central Europe on the deformation behaviour of slender RC walls. The test data documenting the global and local behaviour of the test units is available online and can therefore serve as a reference point for the research community. The experimental results show the importance of the reinforcement content and the ductility properties of both the boundary and web reinforcement for the deformation behaviour of the walls. By comparing base curvatures derived from experimental data with curvatures obtained from section analysis, strain limits characterising different limit states in plastic hinge analysis are suggested. These strain limits can be used in the performance-based design and assessment of RC structural walls.     

竖波钢板组合剪力墙等效塑性铰长度研究

竖波钢板组合剪力墙因内嵌波形钢板的几何形状优势,表现出良好的抗震性能。在基于性能的抗震设计要求下,竖波钢板组合剪力墙等效塑性铰长度的确定对合理评估其塑性变形能力至关重要,但国内外已有公式均难以体现其复杂的组合作用,有待提出针对性的简化计算式。基于课题组前期试验成果,通过对竖波钢板组合剪力墙试验破坏现象和受力机理的分析,采用OpenSEES软件,建立有限元模型。扩展研究波形钢板几何参数、约束边缘H型钢柱、分布钢筋配置、混凝土强度、设计轴压比以及剪力墙高宽比等参数对等效塑性铰长度的影响规律,发现使用波形钢板含钢率可以更有效地反映波形钢板几何参数对等效塑性铰长度的影响,而混凝土强度和分布钢筋配箍率与等效塑性铰长度呈负相关。通过理论分析和推导提出多参数控制的竖波钢板组合剪力墙等效塑性铰长度简化计算式,该式适合于估算竖波钢板组合剪力墙的塑性变形能力,可以用于该类剪力墙的弹塑性分析。     

Implications of using refined plastic hinge analysis for load and resistance factor design

A plastic hinge analysis based on a two-surface stiffness degradation model is outlined for second-order inelastic analysis of steel structures. The analysis approach is based on refinements to the elastic-plastic hinge method and allows for a smooth transition from initial yielding to the full yielding of cross-sections in a beam-column element. This analysis method shows a good representation of the inelastic structural response compared to the conventional elastic-plastic hinge analysis, and it is efficient for use in the analysis design of large-scale structures. Design implications, recommendations and case studies for use of refined plastic hinge analysis for direct frame design considering semirigid connection effects are presented.     

Effect of elaborate plastic hinge definition on the pushover analysis of reinforced concrete buildings

Due to its simplicity, lumped plasticity approach is usually used for nonlinear characterization of reinforced concrete (RC) members in pushover analysis. In this approach, the inelastic force deformation of hinges could be defined as either the nonlinear properties suggested in FEMA‐356 and ATC‐40 or defined hinges quantified on the basis of the properties of RC members. However, the nonlinear response of RC structures relies heavily on the inelastic properties of the structural members concentrated in the plastic hinges. To provide a comparative study, this paper attempts to show the results of pushover analyses of RC structures modeled on the basis of the FEMA nonlinear hinges and defined hinges. Following the validation of the adopted models, the force–deformation curves of the defined hinges are determined in a rigorous approach considering the material inelastic behavior, reinforcement details and dimensions of the members. For the case studies, two four‐story and one eight‐story frames are considered in order to represent low‐rise and mid‐rise buildings with different ductility. Nonlinear responses of both models are elaborated in terms of the inter‐story drift, hinging pattern, failure mechanism and the pushover curve. It is confirmed that FEMA hinges underestimate the strength and more importantly the displacement capacity, especially for the frame possessing low ductility. Copyright © 2012 John Wiley & Sons, Ltd.     

装配式人工消能塑性铰节点抗震性能试验研究

为提高装配式钢筋混凝土(RC)框架结构的抗震性能,降低梁、柱构件震后损伤程度,提出了人工消能塑性铰(artificial dissipated plastic hinge,ADPH)节点,即在梁端通过预埋机械铰实现梁、柱构件铰接,同时安装附加钢板承载并耗能.试验中设计并制作了 2个不同形式的ADPH节点和1个现浇RC节...