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1.
Swaminathan Krishnan 《地震工程与结构动力学》2007,36(7):861-885
This paper describes the three‐dimensional nonlinear analysis of six 19‐storey steel moment‐frame buildings, designed per the 1997 Uniform Building Code, under strong ground motion records from near‐source earthquakes with magnitudes in the range of 6.7–7.3. Three of these buildings possess a reentrant corner irregularity, while the remaining three possess a torsional plan irregularity. The records create drift demands of the order of 0.05 and plastic rotation demands of the order of 4–5% of a radian in the buildings with reentrant corners. These values point to performance at or near ‘Collapse Prevention’. Twisting in the torsionally sensitive buildings causes the plastic rotations on the moment frame on one face of the building (4–5% of a radian) to be as high as twice of that on the opposite face (2–3% of a radian). The asymmetric yield pattern implies a lower redundancy in the lateral force‐resisting system as the failure of the heavily loaded frame could result in a total loss of resistance to torsion. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
2.
Seismic behavior of asymmetric RC wall buildings: principles and new deformation‐based design method
The seismic design of multi‐story buildings asymmetric in plan yet regular in elevation and stiffened with ductile RC structural walls is addressed. A realistic modeling of the non‐linear ductile behavior of the RC walls is considered in combination with the characteristics of the dynamic torsional response of asymmetric buildings. Design criteria such as the determination of the system ductility, taking into account the location and ductility demand of the RC walls, the story‐drift demand at the softer (most displaced) edge of the building under the design earthquake, the allowable ductility (ultimate limit state) and the allowable story‐drift (performance goals) are discussed. The definition of an eccentricity of the earthquake‐equivalent lateral force is proposed and used to determine the effective displacement profile of the building yet not the strength distribution under the design earthquake. Furthermore, an appropriate procedure is proposed to calculate the fundamental frequency and the earthquake‐equivalent lateral force. A new deformation‐based seismic design method taking into account the characteristics of the dynamic torsional response, the ductility of the RC walls, the system ductility and the story‐drift at the softer (most displaced) edge of the building is presented and illustrated with an example of seismic design of a multi‐story asymmetric RC wall building. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
3.
Plan asymmetric buildings are very susceptible to earthquake induced damage due to lateral torsional coupling, and the corners of these systems suffer heavy damage during earthquakes. Therefore, it is important to investigate the seismic behavior of an asymmetric plan building with MR dampers. In this study, the effectiveness of MR damper-based control systems has been investigated for seismic hazard mitigation of a plan asymmetric building. Furthermore, the infl uence of the building parameters and damper command voltage on the control performance is examined through parametric study. The building parameters chosen are eccentricity ratio and frequency ratio. The results show that the MR damper-based control systems are effective for plan asymmetric systems. 相似文献
4.
A pushover procedure with a load pattern based on the height-wise distribution of the combined modal story shear and torsional moment is proposed to estimate the seismic response of 3D asymmetric-plan building frames. Contribution of the higher modes and torsional response of asymmetric-plan buildings are incorporated into the proposed load pattern. The proposed pushover method is a single-run procedure, which enables tracing the nonlinear response of the structure during the analysis and averts the elusiveness of conducting multiple pushover analyses. The proposed method has been used to estimate the response of two moment-resisting building frames with 9 and 20 stories. The obtained results indicate the appropriate accuracy and efficiency of the proposed procedure in estimating the trend of the drift profiles of the structures resulted from nonlinear time history analyses. 相似文献
5.
Recent seismic events have raised concerns over the safety and vulnerability of reinforced concrete moment resisting frame “RC-MRF” buildings. The seismic response of such buildings is greatly dependent on the computational tools used and the inherent assumptions in the modelling process. Thus, it is essential to investigate the sensitivity of the response demands to the corresponding modelling assumption. Many parameters and assumptions are justified to generate effective structural finite element (FE) models of buildings to simulate lateral behaviour and evaluate seismic design demands. As such, the present study focuses on the development of reliable FE models with various levels of refinement. The effects of the FE modelling assumptions on the seismic response demands on the design of buildings are investigated. the predictive ability of a FE model is tied to the accuracy of numerical analysis; a numerical analysis is performed for a series of symmetric buildings in active seismic zones. The results of the seismic response demands are presented in a comparative format to confirm drift and strength limits requirements. A proposed model is formulated based on a simplified modeling approach, where the most refined model is used to calibrate the simplified model. 相似文献
6.
将参数化建模的方法引入减震结构的分析与设计中,通过预设目标和迭代优化计算,以天水市某高层住宅消能减震结构为例,寻找最优的阻尼器布置方案。为评估和验证该消能减震结构的抗震性能,分别采用Perform 3D和ETABS等软件分析结构在多遇和罕遇地震作用下的结构响应,分析结果表明：小震作用下,消能减震结构的楼层位移、层间位移角、楼层弯矩及楼层剪力均减小6.5%以上,达到了设计要求;大震作用下,结构框架柱、框架梁、剪力墙和阻尼器能够满足既定的性能要求,层间位移角满足规范限值,能够达到“大震不倒”的设计目标,研究结果为实际工程预设减震目标和阻尼器优化布置提供参考。 相似文献
7.
Importance of seismic design accidental torsion requirements for building collapse capacity 
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下载免费PDF全文 D. Jared DeBock Abbie B. Liel Curt B. Haselton John D. Hooper Richard A. Henige Jr. 《地震工程与结构动力学》2014,43(6):831-850
Seismic ground motions induce torsional responses in buildings that can be difficult to predict. To compensate for this, most modern building codes require the consideration of accidental torsion when computing design earthquake forces. This study evaluates the influence of ASCE/SEI 7 accidental torsion seismic design requirements on the performance of 230 archetypical buildings that are designed with and without accidental torsion design provisions, taking building collapse capacity as the performance metric. The test case archetypes include a broad range of heights, gravity load levels, and plan configurations. Results show that the ASCE/SEI 7 accidental torsion provisions lead to significant changes in collapse capacity for buildings that are very torsionally flexible or asymmetric. However, only inconsequential changes in collapse capacity are observed in the buildings that are both torsionally stiff and regular in plan. Therefore, the study concludes that accidental torsion provisions are not necessary for seismic design of buildings without excessive torsional flexibility or asymmetry. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
8.
A study is presented of the influence of stiffness and strength eccentricities on the inelastic torsional response of buildings under the action of two simultaneous orthogonal horizontal ground motion components. Asymmetric buildings were obtained from their respective symmetric systems and were characterized by their stiffness and strength torsional eccentricities in both orthogonal directions. Based on the results of inelastic response of both building types (symmetric and asymmetric), the seismic reliability functions are determined for each system, and their forms of variation with different global system parameters are evaluated. Illustrative examples are presented about the use of this information for the formulation of seismic design criteria for in‐plan asymmetric multistory systems, in order to attain the same reliability levels implicit for symmetric systems designed in accordance with current seismic design codes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
9.
Emrah Erduran 《地震工程与结构动力学》2012,41(14):1905-1919
The effects of Rayleigh damping model on the engineering demand parameters of two steel moment‐resisting frame buildings were evaluated. Two‐dimensional models of the buildings were created and response history analysis were conducted for three different hazard levels. The response history analysis results indicate that mass‐proportional damping leads to high damping forces compared with restoring forces and may lead to overestimation of floor acceleration demands for both buildings. Stiffness‐proportional damping, on the other hand, is observed to suppress the higher‐mode effects in the nine‐story building resulting in lower story drift demands in the upper floors compared with other damping models. Rayleigh damping models, which combine mass‐proportional and stiffness‐proportional components, that are anchored at reduced modal frequencies lead to reasonable damping forces and floor acceleration demands for both buildings and does not suppress higher‐mode effects in the nine‐story building. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
10.
This paper presents the main results of the evaluation of residual inter‐story drift demands in typical moment‐resisting steel buildings designed accordingly to the Mexican design practice when subjected to narrow‐band earthquake ground motions. Analytical 2D‐framed models representative of the study‐case buildings were subjected to a set of 30 narrow‐band earthquake ground motions recorded on stations placed in soft‐soil sites of Mexico City, where most significant structural damage was found in buildings as a consequence of the 1985 Michoacan earthquake, and scaled to reach several levels of intensity to perform incremental dynamic analyses. Thus, results were statistically processed to obtain hazard curves of peak (maximum) and residual drift demands for each frame model. It is shown that the study‐case frames might exhibit maximum residual inter‐story drift demands in excess of 0.5%, which is perceptible for building's occupants and could cause human discomfort, for a mean annual rate of exceedance associated to peak inter‐story drift demands of about 3%, which is the limiting drift to avoid collapse prescribed in the 2004 Mexico City Seismic Design Provisions. The influence of a member's post‐yield stiffness ratio and material overstrength in the evaluation of maximum residual inter‐story drift demands is also discussed. Finally, this study introduces response transformation factors, Tp, that allow establishing residual drift limits compatible with the same mean annual rate of exceedance of peak inter‐story drift limits for future seismic design/evaluation criteria that take into account both drift demands for assessing a building's seismic performance. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
11.
Discrepancies between the computed and actual values of the structural element stiffness imply that a building with nominally symmetric plan is actually asymmetric to some unknown degree and will undergo torsional vibration when subjected to purely translational ground motion. Such accidental torsion leads to increase in structural element deformations which is shown to be essentially insensitive to the uncoupled lateral vibration period of the system but is affected strongly by the ratio of uncoupled lateral and torsional vibration periods. The structural deformations increase, in the mean, by at most 10 and 5 per cent for R/C and steel buildings, respectively, and by much smaller amounts for a wide range of system parameters. The increase in structural deformations due to stiffness uncertainty is shown to be much smaller than implied by the accidental torsional provisions in the Uniform Building Code and most other building codes. 相似文献
12.
Zhi Zhang Robert B. Fleischman Jose I. Restrepo Gabriele Guerrini Arpit Nema Dichuan Zhang Ulina Shakya Georgios Tsampras Richard Sause 《地震工程与结构动力学》2018,47(10):1987-2011
A new floor connecting system developed for low‐damage seismic‐resistant building structures is described herein. The system, termed Inertial Force‐Limiting Floor Anchorage System (IFAS), is intended to limit the lateral forces in buildings during an earthquake. This objective is accomplished by providing limited‐strength deformable connections between the floor system and the primary elements of the lateral force‐resisting system. The connections transform the seismic demands from inertial forces into relative displacements between the floors and lateral force‐resisting system. This paper presents the IFAS performance in a shake‐table testing program that provides a direct comparison with an equivalent conventional rigidly anchored‐floor structure. The test structure is a half‐scale, 4‐story reinforced concrete flat‐plate shear wall structure. Precast hybrid rocking walls and special precast columns were used for test repeatability in a 22‐input strong ground‐motion sequence. The structure was purposely designed with an eccentric wall layout to examine the performance of the system in coupled translational‐torsional response. The test results indicated a seismic demand reduction in the lateral force‐resisting system of the IFAS structure relative to the conventional structure, including reduced shear wall base rotation, shear wall and column inter‐story drift, and, in some cases, floor accelerations. These results indicate the potential for the IFAS to minimize damage to the primary structural and non‐structural components during earthquakes. 相似文献
13.
14.
In this study, the torsional response of buildings with peripheral steel‐braced frame lateral systems is evaluated. A three‐dimensional model of a three story braced frame with various levels of eccentricity is created and the effects of torsion on the seismic response is assessed for four hazard levels. The response history analysis results indicate that, unlike frame structures, the torsional amplifications in the inelastic systems exceed those of corresponding elastic systems and tend to increase with an increase in the level of inelasticity. The ability of two simplified procedures, elastic response spectrum analysis and pushover analysis, to capture the torsional amplifications in steel‐braced frames is evaluated. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
15.
Performance based design becomes an effective method for estimating seismic demands of buildings. In asymmetric plan tall building the effects of higher modes and torsion are crucial. The consecutive modal pushover (CMP) procedure is one of the procedures that consider these effects. Also in previous studies the influence of soil-structure interaction (SSI) in pushover analysis is ignored. In this paper the CMP procedure is modified for one-way asymmetric plan mid and high-rise buildings considering SSI. The extended CMP (ECMP) procedure is proposed in order to overcome some limitations of the CMP procedure. In this regard, 10, 15 and 20 story buildings with asymmetric plan are studied considering SSI assuming three different soil conditions. Using nonlinear response history analysis under a set of bidirectional ground motion; the exact responses of these buildings are calculated. Then the ECMP procedure is evaluated by comparing the results of this procedure with nonlinear time history results as an exact solution as well as the modal pushover analysis procedure and FEMA 356 load patterns. The results demonstrate the accuracy of the ECMP procedure. 相似文献
16.
The critical parameters that influence the nonlinear seismic response of asymmetric‐plan buildings are identified by evaluating the effects of different asymmetries that may characterize the structure of a building as well as exploring the influence of the ground motion features. First, the main findings reported in the literature on both the linear and nonlinear dynamic response of asymmetric‐plan buildings are presented. The common findings and the conflicting conclusions reached in different investigations are pointed out. Then, the results of comprehensive nonlinear dynamic analyses performed for evaluating the seismic response of systems characterized by different strength and stiffness configurations, representative of a large class of asymmetric‐plan buildings, are reported. Findings from the study indicate that the building response changes when moving from the linear to the nonlinear range, so that the seismic behavior of asymmetric‐plan buildings, apart from the source of asymmetry, can be always classified as irregular. Additionally, it was observed that as the seismic demands cause amplification of system nonlinearity with increasing earthquake intensity, the maximum displacement demand in the different resisting elements tends to be reached with the same deformed configuration of the system. The resultant of the seismic forces producing such a maximum demand is located at the center of resistance and corresponds to the collapse mechanism of the system that provides the maximum lateral strength in the exciting direction of the seismic action. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
17.
采用弹塑性时程分析程序CANNY对采用框架-非连续抗震墙结构的板式底商住宅进行了罕遇地震作用下的抗震性能分析。计算结果表明,在房屋的底层和端部布置适当数量的抗震墙,可有效提高结构的底层侧向刚度和房屋的整体抗扭刚度,改变了框架结构的抗震不规则形态。在7度罕遇地震作用下,结构弹塑性变形沿竖向分布均匀,无明显薄弱层,结构塑性铰分布合理,可满足规范的抗震设防要求。 相似文献
18.
An indexing method for rapid evaluation of the seismic vulnerability of infi lled RC frame buildings in Jordan is proposed. The method aims at identifying low and medium rise residential buildings as safe or in need of further detailed evaluation. Following a rapid visual screening, the building is assigned a Basic Capacity Index(BCI); fi ve performance modifi ers are identifi ed and multiplied by the BCI to arrive at the Capacity Index(CI) of the building. A Capacity Index lower than a limit CI value indicates that the screened building could experience moderate earthquake damage whereas a higher value implies that minor damage, if any, would take place. To establish the basic evaluation parameters; forty RC frame buildings were selected, designed and analyzed using static nonlinear analysis and incorporating the effect of infi ll walls. Effects of seismicity, local site conditions, horizontal irregularities(setbacks and re-entrant corners), vertical irregularities(soft story at ground fl oor level) and overhangs on the seismic performance of local buildings were examined. Assessment forms were designed and used to evaluate and rank 112 sample buildings. About 40% of the surveyed buildings were found to be in need of detailed evaluation to better defi ne their seismic vulnerabilities. 相似文献
19.
A multi‐level seismic vulnerability assessment of reinforced concrete moment frame buildings located in moderate seismic zones (0.25g) is performed on a set of ductile versions of low‐ to mid‐rise two‐dimensional moment frames. The study is illustrated through application to comparative trial designs of two (4‐ and 8‐story) buildings adopting both space‐ and perimeter‐framed approaches. All frames are dimensioned as per the emerging version of the seismic design code in Egypt. These new seismic provisions are in line with current European norms for seismic design of buildings. Code‐compliant designs (CCD), as well as a proposed modified code design relaxing design drift demands for the investigated buildings, are examined to test their effectiveness and reliability. Applying nonlinear inelastic incremental dynamic analyses, fragility curves (FC) for the frames are developed corresponding to various code‐specified performance levels. Code preset lower and upper bounds on design acceleration and drift, respectively, are also addressed along with their implications, if imposed, on the frames seismic performance and vulnerability. Annual spectral acceleration hazard curves for the case study frames are also generated. Estimates for mean annual frequency (MAF) of exceeding various performance levels are then computed through an integration process of the data resulting from the FC with the site hazard curves. The study demonstrates that the proposed design procedure relaxing design drift demands delivers more economic building designs relative to CCDs, yet without risking the global safety of the structure. The relaxed design technique suggested herein, even though scoring higher, as expected by intuition, MAF of exceeding various code‐limiting performance levels expressed in terms of interstory drift ratios, still guarantees a reasonably acceptable actual margin against violating code limits for such levels. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
20.
《地震工程与结构动力学》2018,47(5):1329-1351
An effective strategy of seismic retrofitting consists of installing nonlinear viscous dampers between the existing building, with insufficient lateral resistance, and some auxiliary towers, specially designed and erected as reaction structures. This allows improving the seismic performance of the existing building without any major alteration to its structural and nonstructural elements, which makes this approach particularly appealing for buildings with heritage value. In this paper, the nonlinear governing equations of the coupled lateral‐torsional seismic motion are derived from first principles for the general case of a multistory building connected at various locations in plan and in elevation to an arbitrary number of multistory towers. This formulation is then used to assess the performance of the proposed retrofitting strategy for a real case study, namely, a 5‐story student hall of residence in the city of Messina, Italy. The results of extensive time‐history analyses highlight the key design considerations associated with the stiffness of the reaction towers and the mechanical parameters of the nonlinear viscous dampers, confirming the validity of this approach. 相似文献