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研究屈曲约束支撑半刚性连接框架弹塑性位移计算方法,为这种结构抗震设计提供依据.推导了屈曲约束支撑半刚性连接框架结构侧移刚度计算方法,通过计算屈曲约束支撑和半刚性连接在罕遇地震作用下的有效阻尼比,修正弹性设计反应谱,再利用修正后的设计反应谱进行结构弹塑性层间位移简化计算.通过与弹塑性时程分析对提出的计算方法进行验证.基于有效阻尼比的思想给出的弹塑性位移的简化计算方法可进行屈曲约束支撑半刚性连接框架罕遇地震下的抗震设计. 相似文献
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目前结构的抗震分析主要是采用刚性地基假定,忽略了土-结构相互作用,而在实际情况中结构的地震破坏与刚性地基假定的预期结果并不相同。为了对比差异,本文以一6层混凝土框架结构为例,分别进行了Pushover分析和非线性时程分析。结果表明:当考虑土-结构相互作用时,结构的基底剪力减小,周期增大,顶点位移增大且结构的破坏主要集中在首层,柱端出现了塑性铰,更符合实际的震害情况。并将Pushover分析与非线性时程分析的结果进行对比,验证了Pushover分析的可靠性。 相似文献
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半刚性连接钢框架结构弹性时程分析 总被引：2，自引：0，他引：2
用两端带转动弹簧的杆单元代替一般的杆单元,提出了一种新的平面杆系钢结构动力弹性时程分析计算模型。采用虚功原理,通过对单元转角-位移方程的修正,推导了这种计算模型的单元质量矩阵,并编制了相应的弹性时程分析计算程序,分析了连接的半刚性在不同地震动作用下对钢框架结构动力性能的影响,并与有限元结果进行了比较。算例结果表明:连接的半刚性对结构动力性能的影响非常大,结构的抗震性能优于刚性连接的情况。 相似文献
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为分析支撑布置方式、刚度比、结构总层数等因素在罕遇地震下对屈曲约束支撑框架结构动力响应的影响,借助有限元分析软件SAP2000,分别对6层、12层、18层屈曲约束支撑框架结构模型进行了罕遇地震下的时程分析,详细研究了多高层结构体系的层间位移角、底层剪力、支撑内力等随支撑布置方式、刚度比、结构总层数等因素变化的规律。分析表明,倒V较单斜布置更能有效降低底层剪力、增大支撑轴力、降低层间位移角,从而降低结构的地震响应,更有利于结构消能减震;随着结构总层数的增大,支撑的屈服层数呈现出增多的趋势;刚度比七为2—4时,能使较多层数的屈曲约束支撑参与到消能减震的过程之中,较好地实现抗震设防目标。 相似文献
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《地震工程与工程振动》2016,(3)
为研究强震作用下柱脚连接刚度对多层钢框架结构抗震性能的影响,利用有限元程序OpenSEES建立了一个4层3跨的钢框架模型,对两种柱脚连接(刚接和半刚接)分别进行罕遇地震下的弹塑性时程分析,对比了结构整体响应、构件滞回曲线、塑性耗能分布等方面的特征。研究结果表明:对于本文所述结构采用半刚接时在罕遇地震下也是安全的,最大层间位移角沿高度的分布趋于均匀;柱脚连接为半刚接,即允许柱脚发生转动承担部分弯矩时,能够提高钢柱的塑性变形能力,防止钢柱底部发生局部屈曲和强度退化;同时整个结构具有更大的延性,地震作用下发生塑性变形和吸收能量的能力增强,使结构具有更大的耗能潜力来防止整个结构发生破坏。 相似文献
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抗拔型三重摩擦摆隔震支座是一种新型隔震支座。以框架结构为例,利用ANSYS软件建立了6层和10层普通抗震结构和带该支座的基础隔震结构模型;通过模态分析,得到了结构的自振周期;通过地震响应分析,提取了6层框架隔震层和顶层的位移、加速度和剪力时程曲线,并提取了不同层数不同结构类型的各层间位移、加速度幅值。结果表明：与抗震结构相比,基础隔震结构周期显著增大;隔震结构的变形主要集中在隔震层,隔震层以上的结构基本为整体平动,结构的地震位移反应得到了有效的减小;采用抗拔型三重摩擦摆隔震支座能降低结构地震加速度反应;设置抗拔型三重摩擦摆隔震支座的多层数隔震结构的能量衰减不如低层数的隔震结构迅速。 相似文献
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为检验抗侧刚度比和支撑布置方式等因素对具有不同总层数的屈曲约束支撑钢框架的抗震性能影响,借助SAP2000软件,探讨6层、12层、18层屈曲约束支撑钢框架结构在抗侧刚度比分别为1、2、3、4、5共五种工况及倒V型和单斜向两种支撑布置方式下的抗震性能。结果表明,屈曲约束支撑钢框架结构基底剪力-顶点位移曲线呈典型的双线性特征;随抗侧刚度比的增大,结构的层间位移角总体上呈降低趋势,基底剪力及支撑轴力增大,顶点水平位移变小,框架所分担的剪力降低;倒V型布置支撑较单斜向布置具有略大的基底剪力、谱加速度,较小的顶点位移、层位移、层间剪力和框架剪力分担率。分析表明,总体上来看,倒V型布置较单斜向布置时支撑框架结构具有略优的抗震性能;抗侧刚度比较支撑布置方式对支撑框架结构抗震性能的影响更为显著。 相似文献
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传统抗弯钢框架的梁柱节点通常设计为刚性连接,这种刚性节点具有很大的抗弯刚度,然而节点延性不足,罕遇地震作用导致节点脆性断裂。研究学者提出了多种解决该问题的思路,例如半刚性连接节点、节点加强或削弱方法使塑性铰外移等。本文提出了一种简化的梁柱节点连接方式-铰接连接,改变梁柱节点的传力方式,在节点处设置隅撑提供框架的抗侧刚度,控制结构的失效模式。本文设计了三组抗弯钢框架和铰接隅撑钢框架,分别为3层、5层和8层结构,通过Pushover分析和非线性动力时程分析,对比二者之间的承载力、刚度、延性和层间侧移等抗震性能。研究结果表明:铰接隅撑钢框架具有和传统抗弯钢框架相似的抗侧刚度,且承载能力略高。罕遇地震作用下,铰接隅撑钢框架的层间侧移较小。传统抗弯钢框架失效模式为梁端出现塑性铰,而铰接隅撑钢框架的塑性区域转移至隅撑与梁连接部位。 相似文献
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Alfredo Reyes-Salazar José M. Sauceda-Pimentel Sonia E. Ruiz Edén Bojórquez Juan Bojorquez 《Bulletin of Earthquake Engineering》2018,16(11):5557-5590
A numerical investigation regarding the seismic behavior of complex-3D steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (GF) is conducted. The interior connections are assumed to be first perfectly pinned (PP) and then semi-rigid (SR); the two model responses are compared. Three steel building models representing low-, medium- and high-rise buildings, and several strong motions are used. The relative stiffness of SR connections is calculated according to the Richard Model and the Beam Line Theory. The Ruaumoko Computer Program is used to perform the required step-by-step nonlinear seismic analysis. Results indicate that interstory shears and interstory displacements at PMRF may be significantly reduced when interior connections are modeled as SR. Average reductions of up to 20, 46 and 11% are observed for interstory shears, for low-, medium-, and high-rise buildings, respectively. The corresponding reductions for interstory displacements are about 14, 44 and 15%. The contribution of GF to the lateral resistance is considerable, which significantly increases when the connections are modeled as SR; relative contributions larger than 80% are observed. The dissipated energy (DE) at PMRF is larger for the buildings with PP than for the buildings with SR connections indicating that damage at PMRF is reduced. Thus, the effect of the stiffness and the DE at interior connections should not be ignored. However, the design of some elements, particularly columns of the GF, has to be revised; these members may not be able to support the loads produced by the neglected lateral contribution if they are not properly designed. 相似文献
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Farhad Behnamfar Sayed Mehdi Taherian Arash Sahraei 《Bulletin of Earthquake Engineering》2016,14(11):3025-3046
In this study a new method for nonlinear static analysis based on the relative displacements of stories is proposed that is able to be implemented in a single stage analysis and considers the effects of an arbitrary number of higher modes. The method is called the extended drift pushover analysis procedure (EDPA). To define the lateral load pattern, values of the relative displacements of stories are calculated using the elastic modal analysis and the modal combination factors introduced. For determining the combination factors, six different approaches are examined. Buildings evaluated in this study consist of four special steel moment-resisting frames with 10–30 stories. Responses including relative displacements of stories, story shear forces and rotation of plastic hinges in each story are calculated using the proposed approaches in addition to modal pushover analysis and nonlinear dynamic time history analyses. The nonlinear dynamic analysis is implemented using ten consistent earthquake records that have been scaled with regard to ASCE7-10. Distribution of response errors of story shears and plastic hinge rotations show that a major part of error corresponds to the second half of the buildings studied. Thus, the mentioned responses are corrected systematically. The final results of this study show that implementing the EDPA procedure using the third approach of this research is able to effectively overcome the limitations of both the traditional and the modal pushover analyses methods and predict the seismic demands of tall buildings with good accuracy. 相似文献
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K. S. Sivakumaran 《地震工程与结构动力学》1991,20(11):1029-1043
In the analysis and design of unbraced steel frames various models are employed to represent the behaviour of beam-to-column connections. In one such model, termed here as ‘Simple Construction’, pinned connections are assumed when resisting gravity loads, whereas the same connections are assumed to be moment-resistant rigid connections when resisting lateral loads due to an earthquake or wind. Such connections are designed for moments due to lateral loads only; thus, they are not only flexible but may yield when the gravity and lateral loads act concurrently. This paper establishes the seismic performance of two (one 5-storey and the other 10-storey) unbraced steel building frames designed based on the ‘Simple Construction’ technique and on limit state principles. The first part of the paper describes briefly the design of such frames and compares their static responses with the corresponding responses of frames designed based on the ‘Continuous Construction’ assumption. Using realistic moment-rotation behaviour for flexible beam-to-column connections and realistic member behaviour, the non-linear dynamic responses of such frames for the 1940 El Centro record and 2 times the 1952 Taft record have been established using step-by-step time-history analyses. Floor lateral displacement envelopes, storey shear envelopes and cumulative inelastic rotations of beams, columns and connections are presented. The results indicate that the ‘Simple Construction’ frames experience larger lateral deflections while attracting lesser storey shears. During a major earthquake, the columns and connections of the ‘Simple Construction’ frames experience yielding, whereas in ‘Continuous Construction’ frames the beams and columns experience yielding. The cyclic plastic rotations in the connections and in the columns associated with ‘Simple Construction’ frames are found to be considerably higher. 相似文献
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Seismic design and experiment of single and coupled corner gusset connections in a full‐scale two‐story buckling‐restrained braced frame 
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下载免费PDF全文 Pao‐Chun Lin Keh‐Chyuan Tsai An‐Chien Wu Ming‐Chieh Chuang Chao‐Hsien Li Kung‐Juin Wang 《地震工程与结构动力学》2015,44(13):2177-2198
A gusset plate is subjected to forces induced from a buckling‐restrained brace (BRB) and frame action. In this study, a performance‐based design method of the gusset connections incorporating a BRB and frame actions is investigated. The force demands resulting from the BRB axial force are computed from the generalized uniform force method. The force demands induced from the frame action effects primarily result from beam shear. A conservative method, which considers the beam axial force effect and the thereafter reduced beam flexural capacity possibly developed at the gusset tips, is adopted in estimating the maximum beam shear. An improved equivalent strut model is used to represent the gusset plate subjected to the frame action effect. The total force demands of the gusset connection are combined from the BRB force and the frame actions. For design purposes, the stress distributions on the gusset interfaces are linearized. The maximum von Mises stress combining the normal and shear stresses is considered as the demand for the gusset plate design. In order to verify the effectiveness of the proposed design method, experiments on a two‐story full‐scale buckling‐restrained braced frame (BRBF) were performed. The chevron and single diagonal brace configurations were arranged in the second and the first stories, respectively. Two different corner gusset connection configurations including one single corner gusset and one coupled corner gusset connection, where two braces in adjacent stories joined at the same beam‐to‐column joint, were tested. The BRBF specimen was subjected to cyclically increasing lateral displacements with a maximum frame drift of 0.04 rad. The maximum story drifts reached 0.035 and 0.061 rad. in the first and the second stories, respectively. At the end of the tests, no fractures were observed on any of the gusset interfaces. Along the gusset interfaces, the normal and shear stress distributions computed from the proposed design procedures and the FEM analysis correlated well with the experimental results. This paper concludes with the procedure and recommendations for the performance‐based design of gusset connections. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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针对单层框架和三层框架,通过高温数值分析,初步考察了不同受火方式下结构的变形特征。研究发现：①火灾蔓延对结构高温变形影响较大,此时节点的水平位移总体上小于结构全层／全部受火时的相应结果;②受火区间仅对相邻跨或相邻层有一定影响,而对隔跨或隔层影响相对较小;③非对称局部受火情况下,单层框架边节点的水平位移可能比全层受火时更大。 相似文献
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The coupled steel plate shear wall (C-SPSW) configuration has been investigated by researchers as a means of improving the overturning stiffness and architectural flexibility of SPSW structures. While C-SPSWs have been shown to exhibit excellent seismic performance, the fabrication cost associated with the high number of moment-resisting connections used in such systems is a potential detraction to their use as an economical solution. Past research has shown that the hysteresis response of SPSWs with simple frame connections is significantly pinched, and as such, most seismic codes prohibit their use in high seismic areas. However, when used in the C-SPSW configuration, a dual system is formed in which the coupling beams not only improve resistance to overturning but also provide substantial lateral strength and energy dissipation capacity. This paper presents an exploration of the potential to improve the economy of C-SPSWs by using the simple boundary frame connections. First, employing the principles of plastic analysis, an attempt is made to quantify the contribution of the coupling beams to the overall lateral load resistance of the system. Then, to evaluate the seismic performance of such C-SPSW systems and allow for the comparison with that of the C-SPSWs with rigid frames, several prototypes are designed and analyzed using a series of nonlinear response history and pushover analyses. The results indicated that the C-SPSWs with simple boundary frames exhibited satisfactory seismic performance comparable with that of the C-SPSWs with rigid frames under both the 10/50 and 2/50 hazard levels, while allowing for reduced fabrication costs. 相似文献
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The fishbone model is a simplified numerical model for moment-resisting frames that is capable of modelling the effects of column-beam strength and stiffness ratios. The applicability of the fishbone model in simulating the seismic responses of reinforced concrete moment-resisting frames of different sets of column-beam strength and stiffness ratios are evaluated through nonlinear static, dynamic and incremental dynamic analysis on six prototype buildings of 4-, 8-and 12-stories. The results show that the fishbone model is practically accurate enough for reinforced concrete frames, although the assumption of equal joint rotation does not hold in all cases. In addition to the ground motion characteristics and the number of stories in the structures, the accuracy of the model also varies with the column-beam stiffness and strength ratios. The model performs better for strong column-weak beam frames, in which the lateral drift patterns are better controlled by the continuous stiffness provided by the strong columns. When the inelastic deformation is large, the accuracy of the model may be subjected to large record-to-record variability. This is especially the case for frames of weak columns. 相似文献
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The paper deals with the applicability of the extended N2 method to base‐isolated plan‐asymmetric building structures. The results obtained by the usual pushover analysis of a 3D structural model are further combined with the aid of linear dynamic (spectral) analysis to account for the dynamic effects caused by structural asymmetry. In the paper, the method has been applied to the seismic analysis of a mass‐eccentric four‐storeyed RC frame building isolated with lead rubber bearings. Three different positions of the center of isolation system (CI) with respect to the center of mass (CM) and the center of stiffness of the superstructure (CS) were considered. The response was analyzed for three different eccentricities, three different torsional to lateral frequency ratios of the superstructure, and two ground motion intensities. The stiffness of the isolators was selected for three different protection levels, which resulted in elastic as well as moderately to excessively damaged superstructure performance levels. The results are presented in terms of the top, base and relative displacements, as well as the stiff/flexible side amplification factors. A more detailed insight into the nonlinear behavior of the superstructure is given in a form of ductility factors for the flexible and stiff side frames. The results of the extended N2 method for selected lateral load distributions are compared with the average results of nonlinear dynamic analyses. It was concluded that the extended N2 method could, with certain limitations, provide a reasonable prediction of the torsional influences in minor to moderately asymmetric base‐isolated structures. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献