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1.
通过收集整理235个实际钻孔资料并建立了2820个计算工况,运用一维波动等效线性化地震反应分析方法,基于不同类别场地条件,研究在不同强度、频谱特性的地震动输入形式下,场地条件对地表地震动参数影响,重点考察地表峰值加速度的变化特征及规律,并对计算结果进行了统计回归分析,给出了不同场地类别条件下地表峰值放大倍数的一般经验值.由于我国现行抗震设计规范中,没有考虑地震烈度或地震动强度对设计反应谱的影响,也没有考虑地震动频谱特性对地表峰值的影响,因此,本文的研究成果可为未来修订抗震设计规范提供参考依据.  相似文献
2.
大高宽比隔震结构地震反应的实用分析方法   总被引:1,自引:1,他引:5  
本文提出了高层隔震结构等大高宽比隔震结构体系地震反应分析的单质点、2质点和3质点剪切型简化计算模型,同时还提出了高宽比影响系数的概念和计算式。这种纯剪切的简化计算模型成功地模拟了剪切加转动多质点计算模型的动力特性,通过高宽比影响系数对剪切型计算模型得到的剪力系数进行非线性放大,使数十质点的隔震结构体系都能够简化成单质点、2质点和3质点体系进行地震反应分析。文末对22层高宽比为5.01的某22层隔震结构进行了算例分析,简化计算理论的计算结果和时程分析法计算结果一致性良好。  相似文献
3.
本文以周期比超限的某偏心结构工程为研究背景,基于SAP2000建立三维有限元模型,采用黏滞阻尼器、黏弹性阻尼器、软钢阻尼器、复合铅黏弹性阻尼器和钢支撑五种减震方案对其进行扭转控制,针对不同扭转控制方案分别进行了模态分析、反应谱分析和动力时程分析,对比研究了多遇地震作用下各控制方案的周期比、层间位移、支撑内力及阻尼器的耗能能力。研究表明:五种控制方案均具有有效抑制结构扭转振动响应的能力,降低结构的最大层间位移角,并使之满足规范要求;后四种控制方案能明显减小结构的周期比,将结构第一扭转反应控制在第三振型;对于此类偏心结构体系的扭转振动控制,本文建议阻尼器设置应尽量远离刚度中心,以达到最佳扭转控制效果。  相似文献
4.
本文在文献[2,1]所建立的平衡重体系运动方程的基础上,对高层建筑电梯系统中平衡重体系的动力特性进行了探讨,给出了求解该体系自振频率的近似方法,通过对一幢14层建筑内的平衡重体系进行的大量地震反应分析,研究了其动力反应沿建筑物高度变化的一般规律,给出了最大反应所处的位置。本文的工作为实施和推广文献[1]所提出的平衡重体系的抗震控制措施奠定了理论基础。  相似文献
5.
通过对运行地震目录管理软件CATMANA.ESE,挑出一守时空范围的地震时出现的错误结果进行分析,得出了正确使用CATMANA.EXE程序的前提条件以及实现这一条件的方法和计算程序。  相似文献
6.
This paper presents estimates of wavenumbers of propagating waves in a seven-story reinforced concrete building in Van Nuys, California, using recorded response to four earthquakes. The phase velocities inferred from these wavenumbers are consistent from one earthquake to another. They are also consistent, inside the building, with independent estimates of the shear wave velocities in the building (e.g. using ambient vibration tests), and along the base, with phase velocities of Love waves typical for San Fernando Valley.  相似文献
7.
For transient, high frequency, and pulse like excitation of structures in the near field of strong earthquakes, the classical design approach based on relative response spectrum and mode superposition may not be conservative. For such excitations, it is more natural to use wave propagation methods. In this paper (Part I), we review several two-dimensional wave propagation models of buildings and show results for theoretical dispersion curves computed for these models. We also estimate the parameters of these models that would correspond to a seven-story reinforced concrete building in Van Nuys, California. Ambient vibration tests data for this building imply vertical shear wave velocity βz=112 m/s and anisotropy factor βxz=0.55 for NS vibrations, and βz=88 m/s and βxz=1 for EW vibrations. The velocity of shear waves propagating through the slabs is estimated to be about 2000 m/s. In the companion paper (Part II), we estimate phase velocities of vertically and horizontally propagating waves between seven pairs of recording points in the building using recorded response to four earthquakes.  相似文献
8.
Equivalent linear dynamic response analysis of ground is based on complex moduli and Fourier series expansion; therefore, it is not an equivalent method but an approximate method. Two deficiencies in the conventional equivalent linear method represented by SHAKE are described first. The maximum shear strength is overestimated, resulting in overestimation of the peak acceleration under a strong ground motion, and the amplification is underestimated at high frequency. The latter sometimes results in underestimation of the peak acceleration under weak ground shaking, and gives an incident wave with unrealistic large accelerations or a divergence of analysis in deconvolution analysis under strong ground motion. Both deficiencies are shown to come from the same cause, i.e. computing the effective strain as a constant fraction of the maximum strain. Since this is a key concept of the equivalent linear analysis, one cannot overcome both deficiencies at the same time in the conventional method. An apparent frequency dependence in stiffness and damping is shown to appear in the dynamic response, although soil itself does not show frequency dependent characteristics. Following this observation, the effective strain is expressed in terms of frequency from the similarity concept of the strain–frequency relationship between time domain and frequency domain. This enables the reduction of both deficiencies at the same time, resulting in a marked improvement in the equivalent linear analysis. The accuracy of the proposed method is examined by the simulations of three vertical array records during large earthquakes. The proposed method always gives much better prediction than conventional equivalent linear methods for both convolution and deconvolution analyses, and it is confirmed to be applicable at more than 1% shear strain.  相似文献
9.
This study proposes a procedure for identifying spectral response curves for earthquake‐damaged areas in developing countries without seismic records. An earthquake‐damaged reinforced concrete building located in Padang, Indonesia was selected to illustrate the identification of the maximum seismic response during the 2009 West Sumatra earthquake. This paper summarizes the damage incurred by the building; the majority of the damage was observed in the third story in the span direction. The damage was quantitatively evaluated using the damage index R according to the Japanese guidelines for post‐earthquake damage evaluation. The damage index was also applied to the proposed spectral response identification method. The seismic performance of the building was evaluated by a nonlinear static analysis. The analytical results reproduced a drift concentration in the third story. The R‐index decreased with an increase in the story drift, which provided an estimation of the maximum response of the building during the earthquake. The estimation was verified via an earthquake response analysis of the building using ground acceleration data, which were simulated based on acceleration records of engineering bedrock that considered site amplification. The maximum response estimated by the R‐index was consistent with the maximum response obtained from the earthquake response analysis. Therefore, the proposed method enables the construction of spectral response curves by integrating the identification results for the maximum responses in a number of earthquake‐damaged buildings despite a lack of seismic records. Copyright © 2016 The Authors. Earthquake Engineering & Structural Dynamics published by John Wiley & Sons Ltd.  相似文献
10.
This paper presents a new type of electromagnetic damper with rotating inertial mass that has been developed to control the vibrations of structures subjected to earthquakes. The electromagnetic inertial mass damper (EIMD) consists of a ball screw that converts axial oscillation of the rod end into rotational motion of the internal flywheel and an electric generator that is turned by the rotation of the inner rod. The EIMD is able to generate a large inertial force created by the rotating flywheel and a variable damping force developed by the electric generator. Device performance tests of reduced‐scale and full‐scale EIMDs were undertaken to verify the basic characteristics of the damper and the validity of the derived theoretical formulae. Shaking table tests of a three‐story structure with EIMDs and earthquake response analyses of a building with EIMDs were conducted to demonstrate the seismic response control performance of the EIMD. The EIMD is able to reduce story drifts as well as accelerations and surpasses conventional types of dampers in reducing acceleration responses. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献
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