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1.
不对称大底板多塔楼隔震结构的地震响应分析 总被引：1，自引：0，他引：1
针对不对称大底板多塔楼隔震结构体系,通过建立地震响应的动力分析简化模型,推导出不对称大底板多塔楼隔震结构体系地震作用下的运动方程。对一实际的不对称大底板多塔楼隔震结构进行地震响应仿真分析,探讨塔楼质量偏心率和塔楼质量比对结构周期比、位移比和层剪力比的影响。结果显示,不对称大底板多塔楼隔震结构扭转角主要由隔震层产生;与不隔震结构相比,不对称大底板多塔楼隔震体系的扭转角减小,可取得较好的减震效果;塔楼与底板的位置分布和质量分布会影响体系的扭转效应和减震效果,应尽量使塔楼的质心与底板质心重合,塔楼质量分布均匀,以减小结构的扭转效应,提高减震效果。 相似文献
2.
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
3.
本文以某一实际平台桩柱为例,对其进行波浪作用以及波浪与地震共同作用研究。依据我国海港水文规范JTJ213-98、DNV的环境条件和环境荷载规范以及API的相关规范[1-3],对波浪荷载的计算采取不同的简化处理方式,从而分析流体的附加质量效应和流固耦合效应在不同工况下对桩柱结构响应的影响,并分析了该影响随工作水深和波浪参数的变化规律。结果表明,两种工况下流体的附加质量效应和流固耦合效应对桩柱响应的影响趋势并不相同,当进行波浪与地震共同作用分析时,有必要考虑流体附加质量效应和流固耦合效应对结构响应的影响。 相似文献
4.
针对地震-台风耦合作用下的近海导管架海洋平台,运用Morison方程将台风对导管架平台的拖曳力及波浪对导管架平台的拖曳力和惯性力施加在结构上,并在基底施加地震动,建立地震-台风耦合作用下的运动方程。通过模态分析,确定结构的基本自振频率,进而选取卓越频率与该频率较为接近的海底地震动进行输入。对通过数值模型计算得到的导管架平台动力响应,参考相关文献中的限值,对耦合作用下的平台进行安全评估,给出了近海导管架海洋平台在地震-台风耦合作用下的损伤状态评定标准。本文关于导管架平台动力响应的统计结果,对导管架结构性态设计具有一定参考意义。 相似文献
5.
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
6.
研究速度脉冲地震和结构质量偏心综合不利条件下新型重力柱-核心筒结构体系的弹塑性反应规律。选取速度脉冲和非速度脉冲地震加速度记录各10条,进行地震动双向输入,采用结构非线性分析软件CANNY进行有限元数值分析,研究脉冲型地震和结构质量偏心对新型体系弹塑性地震反应的影响。分析结果表明,速度脉冲型地震作用下各结构的层间位移角、层间剪力和层间扭转角显著高于非速度脉冲地震下的相应值。质量偏心对结构弹塑性抗震需求影响显著,层间位移角和层间扭转角都随着偏心率的增大而增大,而层间剪力则随偏心率的增大呈减小趋势。建议在重力柱-核心筒结构设计中应重视速度脉冲地震和结构偏心的耦合不利影响。 相似文献
7.
为了增强巨子型有控结构建筑的动力特性,提升其稳定性,设计双向地震波作用下建筑有控结构。采用3种磁流变阻尼器(MRD)与滑移隔震混合控制结构构成单体建筑有控结构,其包括巨结构和子结构,并建立该有控结构的动力分析模型。在动力分析模型中输入水平和竖向地震,得到模型的竖向和水平滑动状态运动微分方程,依据这两个方程采用自适应模糊神经网络优化动力分析模型,构建优化模型。从优化模型出发,通过实例实验分析得出,优化设计双向地震波作用下建筑有控结构时,在其上部结构层间和隔离层各安装一个MRD,可确保优化设计后的有控结构在不同双向地震工况下的地震反应控制效果最佳,且有控结构在双向地震工况2下,结构第一层、中间三层以及顶层的加速度和位移的时程曲线走向一致,且差距微小;同时有控结构的巨结构顶层侧移响应随着子结构刚度增加而提高,动力特性没有明显的变化,子结构随着其自身刚度增加顶层侧移响应表现稳定,子结构动力特性增强。 相似文献
8.
9.
摩擦摆基础隔震上部偏心结构地震反应影响因素分析 总被引：1，自引：0，他引：1
对上部结构存在偏心的摩擦摆基础隔震结构进行了水平双向地震作用下的地震反应分析,研究了上部结构偏心距和抗扭刚度对结构地震反应的影响。分析表明:上部结构偏心距对上部结构和隔震层的位移反应和加速度反应均有较大影响,即使在上部结构偏心距较小时,其对结构地震反应仍有一定程度的影响;上部结构的抗扭刚度对上部结构的加速度反应影响较小,而对上部结构的位移反应影响较大;上部结构的抗扭刚度对隔震层的加速度反应和位移反应影响较小。因而,对于上部结构存在偏心的摩擦摆基础隔震结构,应减小上部结构偏心距并增大其抗扭刚度以减小摩擦摆基础隔震结构的扭转反应。 相似文献
10.
A study is made of the dynamic torsional response of a single mass partially symmetric system to ground excitation. Using the response spectrum technique, the torsional response and dynamic eccentricity are determined as functions of the eccentricity of the system and its uncoupled frequency ratio. It is shown that the dynamic eccentricity can best be expressed as a bilinear function of eccentricity. For the critical condition which occurs when the uncoupled frequency ratio is unity, a comparison is made with the torsional provisions of five seismic codes (Canada, Mexico, New Zealand, ATC3 and Germany). It is shown that the first four codes underestimate the torsional moment, and also the edge displacement of the system, significantly when the eccentricity is small and the uncouped torsional and lateral frequencies are close. 相似文献
11.
In order to mitigate the effect of torsion during earthquakes, most seismic codes of the world provide design guidelines for strength distribution based on the traditional perception that element stiffness and strength are independent parameters. Recent studies have pointed out that for an important class of widely used structural elements such as reinforced concrete flexural walls, stiffness is a strength‐dependent parameter. This implies that the lateral stiffness distribution in a wall‐type system cannot be defined prior to the assignment of elements' strength. Consequently, stiffness eccentricity cannot be computed readily and the current codified torsional provisions cannot be implemented in a straightforward manner. In this study, an alternate guideline for strength distribution among lateral force resisting elements is presented. To develop such a guideline, certain issues related to the dynamic behaviour of asymmetric wall‐type systems during a damaging earthquake were examined. It is shown that both stiffness and strength eccentricity are important parameters affecting the seismic response of asymmetric wall‐type systems. In particular, results indicate that torsional effects can be minimized by using a strength distribution that results in the location of the centre of strength CV and the centre of rigidity CR on the opposite sides of the centre of mass CM. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
12.
An attempt has been made to explore the general trends in the seismic response of plan‐asymmetric structures without any restrictions imposed by a particular code. Systems with structural elements in both orthogonal directions under bi‐directional excitation were studied. Idealized single‐storey models with bi‐axial eccentricity were employed. The systems were torsionally stiff and, in the majority of cases, mass‐eccentric. The main findings are: in general, inelastic torsional response is qualitatively similar to elastic torsional response. Quantitatively, the torsional effect on the flexible side, expressed as an increase of displacements due to torsion, decreases slightly with increasing plastic deformation, unless the plastic deformations are small. The response on the stiff side generally strongly depends on the effect of several modes of vibration and on the influence of the ground motion in the transverse direction. These influences depend on the structural and ground motion characteristics in both directions. Reduction of displacements due to torsion, typical for elastic torsionally stiff structures, usually decreases with increasing plastic deformations. As an additional effect of large plastic deformations, a flattening of the displacement envelopes in the horizontal plane usually occurs, indicating that torsional effects in the inelastic range are generally smaller than in the elastic range. The dispersion of the results of inelastic torsional response analysis is generally larger than that of elastic analysis. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
13.
基础隔震单层偏心结构扭转地震反应分析 总被引：1，自引：0，他引：1
采用微分型滞回恢复力模型模拟隔震支座的恢复力特性，对基础隔震单层偏心结构的扭转地震反应进行分析，研究隔震系统偏心距和上部结构偏心距对结构扭转反应的影响。结果表明，采用隔震技术可以显著降低隔震结构的扭转地震反应。 相似文献
14.
覆水场地地震反应分析 总被引：3，自引：0，他引：3
随着各种海洋结构物的兴建,覆水场地的地震反应逐渐成为研究热点。基于任意拉格朗日-欧拉描述,推导时变区域上的流体运动方程,给出流场、结构的接触条件和流场网格运动控制方法。对于平坦覆水场地,水平向地震动作用下,根据Couette流理论证明该类场地流体作用可以忽略;竖向地震动激励下,横向均匀场地可以通过动水压力公式准确考虑流体作用,横向非均匀场地则需要通过流固耦合方法考虑流体作用,以海底隧道为例加以说明。对于起伏场地,天然起伏场地在地震动激励下的动力反应具有明显的流固耦合特征,以三角形起伏场地为算例;结构物的兴建造成的人工起伏场地同样需要考虑流固耦合效应,以某沉管隧道在水平向地震动激励下的动力反应为算例,并根据结果初步提出该类结构物流固耦合分析的简化计算方法。 相似文献
15.
Stavros A. Anagnostopoulos 《地震工程与结构动力学》1981,9(5):459-476
An evaluation is made of response spectrum techniques as applied to seismic analysis and design of steel template offshore platforms. Such structures are designed as braced space frames for several loading conditions, including the simultaneous action of three earthquake components. Base shears as well as gross forces and combined stresses in members of three different platforms are computed for 30 real, three-component earthquakes and response spectrum predictions, obtained by several modal-spatial combination methods, are compared to time history solutions. Results are presented in the form of error statistics. The three approximations examined are: (a) combination of modes for one component input, (b) combination of the three partial responses to obtain estimates of total response and (c) combination of gross forces to derive maximum design stresses at a section. Attention is focused on corner piles because these are among the most heavily penalized members by three-component excitations. It is shown that commonly used spatial combination rules may underestimate gross forces in design controlling corner members by 15–30 per cent on the average. This is attributed to correlations between motion components that create additive effects along certain directions. Typical estimates of combined stresses, however, are found to be slightly conservative. 相似文献
16.
This paper studies the effect of coherency loss and wave passage on the seismic torsional response of three‐dimensional, multi‐storey, multi‐span, symmetric, linear elastic buildings. A model calibrated against statistical analyses of ground motion records in Mexico City is used for the coherency function. The structural response is assessed in terms of shear forces in structural elements. Incoherence and wave passage effects are found to be significant only for columns in the ground level of stiff systems. The increase of column shears in the ground level is much higher for soft than for firm soil conditions. For the torsionally stiff systems considered, it is found that incoherent and phase‐delayed ground motions do not induce a significant rotational response of the structure. The use of a code eccentricity to account for torsion due to ground motion spatial variation is assessed. On firm soil, the use of a base shear along with an accidental eccentricity results in highly overestimated shear forces; however, for soft soil conditions, code formulations may result in underestimated shear forces. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
17.
Precast concrete panels form attractive facades for steel frame buildings and are generally regarded as non-structural by structural engineers. However, panels have been found to add lateral stiffness until their capacity or that of their connections is exceeded. Consequently, the computed dynamic response based on a model of the structural framing alone may be quite different from that experienced by the actual structure. As a case study, the influence of precast concrete panels on lateral and torsional stiffness of a 25-storey building was investigated. The effect of cladding on dynamic properties and linear seismic response was explored by varying panel stiffness. Cladding stiffness was added to the bare frame model until analytical frequency values matched vibration test results. Then, using the cladding stiffness values obtained, an accidental eccentricity between centres of mass and rigidity at each floor level was imposed and linear seismic response computed. Torsional response effects were increased substantially. Finally, a modified cladding panel connection was developed based on previously-reported studies for panelized construction. The influence of the proposed connection on overall structural response was determined for different ground motion inputs. 相似文献
18.
利用黏弹性人工边界和等效地震荷载时域波动输入方法,结合土层和半空间的精确动力刚度矩阵,实现了地震波斜入射下层状场地地下综合管廊地震反应分析,建立了不同场地条件下地下综合管廊分析模型。计算结果表明:地震波倾斜入射情况下,综合管廊结构地震响应与垂直入射时具有显著差异,一般SV波以30°临界角附近入射时结构地震反应最为剧烈;地下综合管廊动应力集中主要分布在管廊角部、中柱上下端;成层土波速结构变化对地下综合管廊地震反应亦具有显著影响。总体上看:当穿越软夹层时管廊结构地震反应更为剧烈,且覆盖层越厚,管廊结构内力幅值越大。因此地下综合管廊结构抗震设计宜考虑地震波倾斜入射及场地土层性质的影响。 相似文献
19.
以一座主跨为820 m的双塔非对称单侧混合梁斜拉桥为研究对象,对其进行动力特性分析。运用相对运动法进行多点激励地震响应计算,分析行波效应对塔顶、主梁、塔底等关键位置动力响应的影响,同时对比分析入射角方向（即斜拉桥两侧相对方向）对其动力响应的影响。结果表明：与一致激励分析结果相比,多点激励使得主塔内力结果偏小,而使得主梁内力结果偏大;不同入射角地震激励对非对称大跨度斜拉桥的内力也会产生较大影响,内力变化可达20%。因此,在进行该类型非对称混合梁斜拉桥设计中,应考虑非一致激励效应和地震动输入方向的影响因素。 相似文献
20.
An investigation on the ground motion parameters and seismic response of underground structures 
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下载免费PDF全文 Peak ground acceleration (PGA), frequency content and time duration are three fundamental parameters of seismic loading. This study focuses on the seismic load frequency and its effect on the underground structures. Eight accelerograms regarding different occurred earthquakes that are scaled to an identical PGA and variation of ground motion parameters with ratio of peak ground velocity (PGV) to PGA, as a parameter related to the load frequency, are considered. Then, concrete lining response of a circular tunnel under various seismic conditions is evaluated analytically. In the next, seismic response of underground structure is assessed numerically using two different time histories. Finally, effects of incident load frequency and frequency ratio on the dynamic damping of geotechnical materials are discussed. Result of analyses show that specific energy of seismic loading with identical PGA is related to the seismic load frequency. Furthermore, incident load frequency and natural frequency of a system have influence on the wave attenuation and dynamic damping of the system. 相似文献