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1.
To investigate the seismic behavior of I-section columns made of 460 MPa high strength steel(HSS), six specimens were tested under constant axial load and cyclic horizontal load. The specimens were designed with different width-to-thickness ratios and loaded under different axial load ratios. For each specimen, the failure mode was observed and hysteretic curve was measured. Comparison of different specimens on hysteretic characteristic, energy dissipation capacity and deformation capacity were further investigated. Test results showed that the degradation of bearing capacity was due to local buckling of flange and web. Under the same axial load ratio, as width-to-thickness ratio increased, the deformation area of local buckling became smaller. And also, displacement level at both peak load and failure load became smaller. In addition, the full extent of hysteretic curve, energy dissipation capacity, ultimate story drift angle decreased, and capacity degradation occurred more rapidly with the increase of width-to-thickness ratio or axial load ratio. Based on the capacity of story drift angle, limiting values which shall not be exceeded are suggested respectively for flange and web plate of 460 MPa HSS I-section columns when used in SMFs and in IMFs in the case of axial load ratio no more than 0.2. Such values should be smaller when the axial load ratio increases. 相似文献
2.
The seismic performance of two RC interior wide beam-column connections representative of existing frames designed and detailed
according to past construction practices in the moderate-seismicity Mediterranean area was investigated experimentally. The
specimens were subjected to axial loads, moderate levels of gravity loading and cyclic displacements up to failure. The specimens
exhibited a “strong column-weak beam” type of flexural yielding mechanism. The wide beams did not reach the expected capacities
corresponding to the formation of a full-width plastic hinge. The wide-beam longitudinal bars exhibited significant slippage,
and the transverse beams underwent severe torsion cracking and even failure; this caused severe pinching in the load versus
displacement hysteretic loops and exacerbated the intrinsic flexibility of this type of connection. The average drift ratios
at first yielding of the wide beam longitudinal reinforcement and at failure were 2.7 and 4.5%, respectively. The displacement
ductility ratio was about 2.8. The ultimate energy dissipation capacity of each specimen—obtained by dividing the total plastic
strain energy by the product of the yield load and yield displacement—was approximately 9, which is about one fourth of the
value recommended for providing adequate seismic performance. Finally, a simple approach is suggested for prediction of the
bending capacity of existing connections. 相似文献
3.
《地震工程与结构动力学》2018,47(5):1250-1269
Reinforced concrete waffle‐flat plate (WFP) structures present 2 important drawbacks for use as a main seismic resisting system: low lateral stiffness and limited ductility. Yet the former can serve a positive purpose when, in parallel, the flexible WFP structure is combined with a stiff system lending high‐energy dissipation capacity, to form a “flexible‐stiff mixed structure.” This paper experimentally investigates the seismic performance of WFP structures (flexible system) equipped with hysteretic dampers (stiff system) through shake‐table tests conducted on a 2/5‐scale test specimen. The WFP structure was designed only for gravitational loads. The lateral strength and stiffness provided by the dampers at each story were, respectively, about 3 and 7 times greater than those of the bare WFP structure. The mixed system was subjected to a sequence of seismic simulations representing frequent to very rare ground motions. Under the seismic simulations associated with earthquakes having return periods ranging from 93 to 1894 years, the WFP structure performed in the level of “immediate occupancy,” with maximum interstory drifts up to about 1%. The dampers dissipated most (75%) of the energy input by the earthquake. 相似文献
4.
Design of hysteretic dampers with optimal ductility for the transverse seismic control of cable‐stayed bridges 
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下载免费PDF全文 Alfredo Camara Roberto Cristantielli Miguel A. Astiz Christian Málaga‐Chuquitaype 《地震工程与结构动力学》2017,46(11):1811-1833
Cable‐stayed bridges require a careful consideration of the lateral force exerted by the deck on the towers under strong earthquakes. This work explores the seismic response of cable‐stayed bridges with yielding metallic dampers composed of triangular plates that connect the deck with the supports in the transverse direction. A design method based on an equivalent single‐degree of freedom approximation is proposed. This is proved valid for conventional cable‐stayed bridges with 200‐ and 400‐m main spans, but not 600 m. The height of the plates is chosen to (1) achieve a yielding capacity that limits the maximum force transmitted from the deck to the towers, and to (2) control the hysteretic energy that the dampers dissipate by defining their design ductility. In order to select the optimal ductility and the damper configuration, a multi‐objective response factor that accounts for the energy dissipation, peak damper displacement and low‐cycle fatigue is introduced. The design method is applied to cable‐stayed bridges with different spans and deck–support connections. The results show that the dissipation by plastic deformation in the dampers prevents significant damage in the towers of the short‐to‐medium‐span bridges under the extreme seismic actions. However, the transverse response of the towers in the bridge with a 600‐m main span is less sensitive to the dampers. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
5.
Geoffrey W. Rodgers Kevin M. Solberg J. Geoffrey Chase John B. Mander Brendon A. Bradley Rajesh P. Dhakal Luoman Li 《地震工程与结构动力学》2008,37(13):1549-1564
Ductile‐jointed connections, which generally require some form of supplementary energy dissipation to alleviate displacement response, typically employ mild steel energy dissipation devices. These devices run the risk of low‐cycle fatigue, are effective only for peak cycles that exceed prior displacements, are prone to buckling, and may require replacement following an earthquake. This study presents an experimental investigation employing an alternative to mild steel: a high force‐to‐volume (HF2V) class of damper‐based energy dissipation devices. Tests are performed on a near full‐scale beam–column joint subassembly utilizing externally mounted compact HF2V devices. Two configurations are considered: an exterior joint with two seismic beams and one gravity beam framing into a central column, and a corner joint with only one seismic beam and one gravity beam framing into a column. Quasi‐static tests are performed to column drifts up to 4%. The experiments validate the efficacy of the HF2V device concept, demonstrating good hysteretic energy dissipation, and minimal residual device force, allowing ready re‐centring of the joint. The devices dissipate energy consistently on every cycle without the deterioration observed in the yielding steel bar type of devices. The effectiveness of the HF2V devices on structural hysteretic behavior is noted to be sensitive to the relative stiffness of the anchoring elements, indicating that better efficiency would be obtained in an embedded design. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
6.
为了进一步完善Q460钢材在抗震设计规范中相关限值的要求,本文利用有限元软件ABAQUS,以轴压比、翼缘宽厚比、腹板高厚比和壁板宽厚比为变量,建立了共48根“工”字型框架柱和“箱”型框架柱,分析了其抗震性能。结果表明:翼缘宽厚比对框架柱的能量耗散系数影响较小;能量耗散系数随轴压比、腹板高厚比（“工”字型）和壁板宽厚比（“箱”型）增大而明显减小;框架柱的极限承载力随轴压比的减小及壁板宽厚比和翼缘宽厚比的增大而逐渐增大,当腹板高厚比接近规范限值时,承载力下降趋势明显增大。与采用Q235钢材的框架柱相比,Q460钢材框架柱的延性较小,仅为2左右;当采用Q460钢材时,“工”字型框架柱的极限位移角限值建议取为0.03,“箱”型框架柱的极限位移角限值建议取为0.032。规范中对翼缘宽厚比限值的规定偏于保守,其值最大可取至9。无论是“工”字型框架柱还是“箱”型框架柱,其腹板高厚比均不宜过大。Q460钢材框架柱的刚度退化率随轴压比的增大而增强,且翼缘宽厚比越大,腹板高厚比越小,柱的初始刚度越大,刚度退化程度越明显。 相似文献
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This paper evaluates the hysteretic behavior of an innovative compressed elastomer structural damper and its applicability to seismic‐resistant design of steel moment‐resisting frames (MRFs). The damper is constructed by precompressing a high‐damping elastomeric material into steel tubes. This innovative construction results in viscous‐like damping under small strains and friction‐like damping under large strains. A rate‐dependent hysteretic model for the compressed elastomer damper, formed from a parallel combination of a modified Bouc–Wen model and a non‐linear dashpot is presented. The model is calibrated using test data obtained under sinusoidal loading at different amplitudes and frequencies. This model is incorporated in the OpenSees [17] computer program for use in seismic response analyses of steel MRF buildings with compressed elastomer dampers. A simplified design procedure was used to design seven different systems of steel MRFs combined with compressed elastomer dampers in which the properties of the MRFs and dampers were varied. The combined systems are designed to achieve performance, which is similar to or better than the performance of conventional steel MRFs designed according to current seismic codes. Based on the results of nonlinear seismic response analyses, under both the design basis earthquake and the maximum considered earthquake, target properties for a new generation of compressed elastomer dampers are defined. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
9.
通过对采用高强钢筋的6片T形混凝土短肢剪力墙和采用高强钢筋高强混凝土的6片L形短肢剪力墙进行低周往复加载试验,研究了T形和L形的破坏形态与性能差异,分析了高厚比、轴压比、配箍间距等参数对构件破坏形态、滞回耗能、骨架曲线、延性及耗能等抗震性能的影响,对比分析了构件与普通短肢剪力墙的抗震性能差异。试验结果表明:采用腹板端部箍筋加密的方式可减轻构件端部的损伤和降低正负向加载时承载力和延性的不对称性;T形构件中高厚比为5的试件表现为弯曲破坏,其他构件表现为弯剪破坏;试验中高厚比小的构件相对于高厚比大的试件延性耗能更好,轴压比增大,构件承载力提高但延性降低;与普通短肢剪力墙相比,T形短肢剪力墙承载力和变形能力提高,耗能增加,L形短肢剪力墙承载力提高较大,极限位移增大,构件后期变形能力略有降低,但可以满足抗震性能要求。 相似文献
10.
地震时砌体结构窗间墙易发生破坏,为了提高其抗震性能,对高宽比为1的2组共4片墙体,其中:2片为双层打包带加固墙体,2片为原墙,进行了拟静力试验,研究墙体的破坏形态、水平承载力、滞回曲线和耗能等抗震性能。试验发现原墙发生剪切破坏,加固后墙体发生摇摆破坏,加固改变了墙体破坏模式,加固后墙体滞回曲线饱满但有捏笼,破坏荷载、延性和耗能能力都有提高,破坏时未发生剥离,表明双层打包带加固法有效地提高了窗间墙体抗震性能,对承受较大竖向应力墙体效果更好,建议加固时要加强加固层与窗下和窗上墙体的连接。 相似文献
11.
Systematic development of a new hysteretic damper based on torsional yielding: part II—experimental phase 下载免费PDF全文
下载免费PDF全文 This paper reports on experimental studies carried out on a 200 kN, 120 mm‐capacity prototype of the newly developed multidirectional torsional hysteretic damper for seismic protection of structures. The main goal of the experiments is to test the validity of the theory developed in a companion paper and to evaluate the low‐cycle fatigue performance of the energy dissipaters of the damper. Because the design and configuration of the damper allow easy replacement of the energy dissipaters, four sets of energy dissipaters were produced out of S355J2 + N, C45 (two sets), and 42CrMo4 + QT steel grades. Force–displacement response of the multidirectional torsional hysteretic damper is studied through fully reversed cyclic quasi‐static displacement‐controlled tests that were carried out in compliance with EN 15129. Following the verification tests, with the aim of studying fatigue and fracture behavior of the cylindrical energy dissipaters of the device, certain numbers of them were subjected to further cyclic tests up to failure, and observations on their fatigue/fracture behavior are reported. The experimental verification test results proved the validity of the developed theory and component design assumptions presented in a companion paper. Furthermore, the energy dissipaters exhibited excellent torsional low‐cycle fatigue performance with number of cycles to failure reaching 118 at a maximum shear strain of 8% for S355J2 + N steel grade. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
12.
Seismic performance and damage evaluation of a reinforced concrete frame with hysteretic dampers through shake‐table tests 下载免费PDF全文
下载免费PDF全文 Passive energy dissipation devices are increasingly implemented in frame structures to improve their performance under seismic loading. Most guidelines for designing this type of system retain the requirements applicable to frames without dampers, and this hinders taking full advantage of the benefits of implementing dampers. Further, assessing the extent of damage suffered by the frame and by the dampers for different levels of seismic hazard is of paramount importance in the framework of performance‐based design. This paper presents an experimental investigation whose objectives are to provide empirical data on the response of reinforced concrete (RC) frames equipped with hysteretic dampers (dynamic response and damage) and to evaluate the need for the frame to form a strong column‐weak beam mechanism and dissipate large amounts of plastic strain energy. To this end, shake‐table tests were conducted on a 2/5‐scale RC frame with hysteretic dampers. The frame was designed only for gravitational loads. The dampers provided lateral strength and stiffness, respectively, three and 12 times greater than those of the frame. The test structure was subjected to a sequence of seismic simulations that represented different levels of seismic hazard. The RC frame showed a performance level of ‘immediate occupancy’, with maximum rotation demands below 20% of the ultimate capacity. The dampers dissipated most of the energy input by the earthquake. It is shown that combining hysteretic dampers with flexible reinforced concrete frames leads to structures with improved seismic performance and that requirements of conventional RC frames (without dampers) can be relieved. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
13.
腹板开孔耗能支撑有效地避免了传统中心支撑斜杆的失稳破坏,具有较强的耗能能力.为研究腹板开孔形状对支撑滞回性能的影响,对腹板开菱形孔、椭圆孔及长圆孔耗能支撑试件进行了低周往复加载试验,分析了试件在循环荷载作用下的破坏机理、滞回性能、承载能力、刚度退化及耗能能力.试验结果表明:耗能支撑试件滞回曲线饱满,耗能性能优越.耗能支... 相似文献
14.
提出一种组合型减震结构,由钢框架、节点阻尼器和原结构连接组成,外附钢框架将节点阻尼器连接在原混凝土框架结构上形成的增设节点阻尼器的外附钢框架结构,节点阻尼器的剪切滞回变形可以减小结构自身需要消耗的能量,从而提高原结构抗震性能。对原混凝土结构和增设节点阻尼器的组合型结构进行了的振动台试验。通过分析结构在不同地震波激励下的加速度和位移响应,得出楼层加速度和层位移的减震效果。研究结果表明:该结构体系在小震作用下通过提高结构刚度来增强其抗震性能;在大震作用下则可借助节点阻尼器的变形耗能来提升结构耗能能力,结构加速度减震系数达到53%,层间位移减震系数高达72%,验证了增设节点阻尼器的外附钢框架结构的减震效果。 相似文献
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斜拉桥纵向设置粘滞阻尼器参数分析 总被引：4，自引：2，他引：4
采用Maxwell阻尼模型模拟了粘滞阻尼器的滞回耗能特性。通过对设置粘滞阻尼器斜拉桥纵向非线性地震反应的分析，讨论了粘滞阻尼器各参数对结构地震响应的影响，并通过计算证实了粘滞阻尼器具有良好的消能减振效果。 相似文献
16.
This paper presents the results of a probabilistic evaluation of the seismic performance of 3D steel moment‐frame structures. Two types of framing system are considered: one‐way frames typical of construction in the United States and two‐way frames typical of construction in Japan. For each framing system, four types of beam–column connections are considered: pre‐Northridge welded‐flange bolted‐web, post‐Northridge welded‐flange welded‐web, reduced‐beam‐section, and bolted‐flange‐plate connections. A suite of earthquake ground motions is used to compute the annual probability of exceedence (APE) for a series of drift demand levels and for member plastic‐rotation capacity. Results are compared for the different framing systems and connection details. It is found that the two‐way frames, which have a larger initial stiffness and strength than the one‐way frames for the same beam and column volumes, have a smaller APE for small drift demands for which members exhibit no or minimal yielding, but have a larger APE for large drift demands for which members exhibit large plastic rotations. However, the one‐way frames, which typically comprise a few seismic frames with large‐sized members that have relatively small rotation capacities, may have a larger APE for member failure. The probabilistic approach presented in this study may be used to determine the most appropriate frame configuration to meet an owner's performance objectives. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
17.
Post‐tensioned (PT) self‐centering moment‐resisting frames (MRFs) have recently been developed as an alternative to welded moment frames. The first generation of these systems incorporated yielding energy dissipation mechanisms, whereas more recently, PT self‐centering friction damped (SCFR) moment‐resistant connections have been proposed and experimentally validated. Although all of these systems exhibited good stiffness, strength and ductility properties and stable dissipation of energy under cyclic loading, questions concerning their ultimate response still remained and a complete design methodology to allow engineers to conceive structures using these systems was also needed. In this paper, the mechanics of SCFR frames are first described and a comprehensive design procedure that accounts for the frame behavior and the nonlinear dynamics of self‐centering frames is then elaborated. A strategy for the response of these systems at ultimate deformation stages is then proposed and detailing requirements on the beams in order to achieve this response are outlined. The proposed procedure aims to achieve designs where the interstory drifts for SCFR frames are similar to those of special steel welded moment‐resisting frames (WMRFs). Furthermore, this procedure is adapted from current seismic design practices and can be extended to any other PT self‐centering steel frame system. A six‐story building incorporating WMRFs was designed and a similar building incorporating SCFR frames were re‐designed by the proposed seismic design procedure. Time‐history analyses showed that the maximum interstory drifts and maximum floor accelerations of the SCFR frame were similar to those of the WMRF but that almost zero residual drifts were observed for the SCFR frame. The results obtained from the analyses confirmed the validity of the proposed seismic design procedure, since the peak drift values were similar to those prescribed by the seismic design codes and the SCFR frames achieved the intended performance level under both design and maximum considerable levels of seismic loading. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Buckling is usually conceived as an unstable structural behavior leading to lateral instability of axially loaded members, if not properly supported. However, a pre‐bent strip would become an excellent seismic energy‐dissipative device if it is deformed in a guided direction and range. Geometrically large lateral deformation of the steel strips in buckling leads to inelastic behavior of the material and dissipates energy as a consequence. The purpose of this study is to propose a new type of seismic damper in the form of braces based on pre‐bent steel strips. The nonlinear elastic stiffness of monotonously loaded pre‐bent strips in both compression and tension is derived. The energy‐dissipative characteristics of the proposed damping device are investigated via component tests under cyclic loads. Experimental results indicate that the force–displacement relationship of pre‐bent strips in cyclic loads exhibits mechanical characteristics of displacement‐dependent dampers. A series of seismic performance tests has been conducted further to verify the feasibility and effectiveness of using the proposed device as seismic dampers. Encouraging test results have been obtained, suggesting feasibility of the proposed device for earthquake‐resistant design. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
20.
提出一种带可更换软钢阻尼器的低损伤自复预制混凝土(LDSCPC)框架节点,并针对该节点在地震作用下的抗震性能、更换阻尼器后的性能恢复等开展足尺试件的拟静力试验。在节点试验基础上,基于ABAQUS精细化有限元模型进行该节点关于螺栓预紧力、水平和竖向耗能条尺寸的参数化分析及优化设计。研究表明,软钢阻尼器LT12的滞回特性和承载能力是最优异的,而LT14是耗能最好的;增加阻尼器耗能条的尺寸和厚度能分别提高LDSCPC框架节点在加载早期和变形较大时的耗能性能。较大的螺栓预紧力能明显提升LDSCPC框架节点的耗能能力,当预紧力为155 kN时,软钢阻尼器几乎达到理想的耗能性能。 相似文献