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隧道开挖时的爆破震动对周边建筑物安全影响很大,但目前对不同爆破参数、周边建筑的距离与爆破开挖之间关系的研究成果不多,实际工程中也难以把握。以宁夏固原市某水工隧道工程为依托,采用现场试验的方法,对地表关键位置质点爆破振动频率与振动速度进行测试和分析。结果表明:(1)经测试发现房屋主振频率在10~60Hz间,而一般房屋建筑的频率均小于10Hz,说明此次试验中爆破震动不能与房屋产生共振。(2)对试验数据进行分析,并依据爆破震动规范安全振速标准进行判别,发现此次试验中土坯房的安全距离为160 m,一般砖房为60 m。研究结果可为隧道爆破的设计与施工提供理论依据,为类似隧道的爆破工程及解决由爆破引起的纠纷提供借鉴。 相似文献
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Clotaire Michel Philippe Guguen Saber El Arem Jacky Mazars Panagiotis Kotronis 《地震工程与结构动力学》2010,39(4):419-441
In countries with a moderate seismic hazard, the classical methods developed for strong motion prone countries to estimate the seismic behaviour and subsequent vulnerability of existing buildings are often inadequate and not financially realistic. The main goals of this paper are to show how the modal analysis can contribute to the understanding of the seismic building response and the good relevancy of a modal model based on ambient vibrations for estimating the structural deformation under weak earthquakes. We describe the application of an enhanced modal analysis technique (frequency domain decomposition) to process ambient vibration recordings taken at the Grenoble City Hall building (France). The frequencies of ambient vibrations are compared with those of weak earthquakes recorded by the French permanent accelerometric network (RAP) that was installed to monitor the building. The frequency variations of the building under weak earthquakes are shown to be less (∼2%) and therefore ambient vibration frequencies are relevant over the elastic domain of the building. The modal parameters extracted from ambient vibrations are then used to determine the 1D lumped‐mass model in order to reproduce the inter‐storey drift under weak earthquakes and to fix a 3D numerical model that could be used for strong earthquakes. The correlation coefficients between data and synthetic motion are close to 80 and 90% in horizontal directions, for the 1D and 3D modelling, respectively. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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The seismic performance assessment of existing masonry buildings involves many uncertainties, whose impact can be reduced to some extent by using non-destructive in-situ tests of such buildings, at least when destructive in-situ tests, which can provide more reliable results, cannot be performed. In this paper the extent of the potential beneficial effects achievable by calibration of a structural model of a building to its experimentally estimated vibration periods has been investigated. This was done by performing measurements of ambient and forced vibrations on an old two-storey masonry building, and by then assessing its seismic performance using a simplified nonlinear method. The results of numerical investigations revealed that the natural vibration periods of such buildings can be reproduced with sufficient accuracy, although it is possible that they will be overestimated or underestimated by analysts by up to around 40 %. This means that the accuracy of the prediction of the intermediate results of the seismic performance assessment of any particular building can be significantly increased by calibration of the structural model. Additionally, the beneficial effects of such calibration were observed even in the case of the final outcome of the nonlinear analysis, which is expressed through the near-collapse limit state capacity in terms of the peak ground acceleration. 相似文献
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Comparison between seismic vulnerability models and experimental dynamic properties of existing buildings in France 总被引:4,自引:3,他引:1
Elastic fundamental frequency is a key-parameter of simplified seismic design and vulnerability assessment methods. Empirical
relationships exist in codes to estimate this frequency but they miss experimental data to validate them accounting for national
feature of building design and, above all, corresponding uncertainties. Even if resonance frequency extracted from ambient
vibrations may be larger than the elastic frequency (at yield) generally used in earthquake engineering, ambient vibration
recordings may provide a large set of data for statistical analysis of periods versus building characteristics relationships.
We recorded ambient vibrations and estimated the fundamental frequency of about 60 buildings of various types (RC and masonry)
in Grenoble City (France). These data complete the set existing yet, made of 26 RC-buildings of Grenoble (Farsi and Bard 2004)
and 28 buildings in Nice (France) (Dunand 2005). Statistical analysis of these experimental data was performed for fundamental
frequencies of RC shear wall structures and the results are compared with existing relationships. Only building height or
number of stories has a statistical relevancy to estimate the resonance frequency but the variability associated to the proposed
relationships is large. Moreover, we compared the elastic part of capacity curves of RC and masonry buildings used in the
European Risk-UE method for vulnerability assessment with the experimental frequencies. The variability is also large and
the curves may not be consistent with French existing buildings. 相似文献
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Following the Mw 7.3 Martinique earthquake, November 29th, 2007, a post-seismic survey was conducted by the Bureau Central Sismologique Français (BCSF) for macroseismic intensities assessment. In addition to the inventories, ambient vibration recordings were performed close to the particularly damaged zones in the free-field and the buildings. The objective of the paper is to show the relevancy of performing ambient vibration recordings for post-earthquake surveys. The analyses of the recordings aim at explaining the variability of the damages through site effects, structure vulnerability or resonance phenomena and to help the characterization of the post-seismic building integrity. In three sites prone to site effects, we suspect damage to be related to a concordance between soil fundamental frequency and building resonance frequency. Besides, the recordings of ambient vibrations at La Trinité hospital before and after the earthquake allow us to quantify the damage due to earthquake in terms of stiffness loss. 相似文献
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全球地震台网(GSN)及中国地震台网(CENC)的地震观测数据分析表明:由北大西洋、北冰洋等海域进入北欧的强冷涡气旋(北欧风暴)能引发与其过程相关联的震动,其中由挪威海登陆斯堪的纳维亚半岛的强气旋风暴引发的震动波,几乎可以被整个欧亚大陆的地震仪观测到,该震动主要包含两个信号:一个主频为0.15~0.25 Hz(周期约4~7 s);而另一个是主频为0.08~0.12 Hz(周期8~12 s)的面波信号,它们分别来自不同的产生机理.不同海域和地区的风暴引发的震动信号存在差异,与气旋运动路径经过的地形地貌特征有关,气旋经过的浅海区域、海水深度、登陆地点的地形以及气旋的结构、观测点相对气旋的分布等因素决定了气旋在运动中激发有独特的震动信号.地震观测可以监测气旋在时间和空间的发展变化过程,有助于探索气旋运动过程中与地球表面的相互作用对气旋的影响. 相似文献
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Empirical relationships between natural vibration period and height of buildings in Singapore
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Singapore is a classic case of a modern metropolis with low hazard but high exposure to the seismicity in Sumatra. Because of land shortage, more than 80% of the population lives in high‐rise residential buildings. As part of the efforts to assess the seismic performance of buildings in Singapore subjected to long‐distance Sumatran earthquakes, relationships between the natural vibration period and height of high‐rise public residential buildings in Singapore are derived empirically by conducting ambient vibration tests on 116 buildings. The measured buildings have a height ranging from 4 to 30 stories. The aspect ratio of buildings in plan is found to be insignificant in affecting the natural vibration period of the first mode of the buildings. The period‐height relationships are derived using regression analysis considering the site properties of a building. It is concluded that the vibration periods estimated from the proposed period‐height relationship for buildings located at soft‐soil site are about 40% longer than the vibration periods estimated for buildings located at firm‐soil site. Measurements are also conducted to study the influence of buildings on the measured frequency of the surrounding soil. For this purpose, two buildings with 25 and 30 stories located at firm‐soil site and soft‐soil site, respectively, are selected. It is found that the distance of building influence on the measured frequency of the surrounding soil may reach up to one building height for a firm‐soil site and two building heights for a soft‐soil site. Additional data of natural vibration periods of 19 instrumented residential buildings, which have height ranging from 9 to 30 stories, were obtained from the building response recorded during the September 30, 2009 Sumatran earthquake event. The natural vibration periods of these buildings are compared with those estimated using the proposed period‐height relationships, and the absolute differences are found to be less than 12%. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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为开展MEMS型加速度传感器在超高层建筑振动监测应用中的性能对比测试,选取4种不同类型MEMS型加速度传感器与G1B型力平衡式加速度传感器,将其安装在地王大厦相同测点,对MEMS型、G1B型加速度传感器记录的结构环境振动数据进行时程、频谱和模态频率对比分析,并对其记录的结构地震响应进行时域及频域对比。研究结果表明,不同类型MEMS型加速度传感器仪器噪声均大于G1B型加速度传感器,其中MEMS-I型加速度传感器噪声水平相对较小,与G1B型加速度传感器模态频率识别结果及地震响应监测数据吻合较好,验证了MEMS-I型加速度传感器可较准确地记录到结构强振动响应,适用于超高层建筑日常结构振动监测。 相似文献
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More than 30 buildings around Taiwan have been selected to monitor the floor responses under seismic excitation. The structural array monitoring system in each building controls at most 27 channels of accelerometers distributed in several floors. Those buildings were triggered by many events during the past five years of operation. In each building, the records at the basement can be considered as the ground excitation, and the others at the upper floors are the structural responses. The frequency transfer functions of those buildings can be identified by ARX models, and then the fundamental vibration periods are estimated. The identified fundamental vibration periods using different events are compared in order to ensure the reliability of system identification. An empirical formula in predicting the fundamental vibration period is presented through the regression analysis to the identified fundamental vibration periods of 21 reinforced concrete (RC) moment‐resisting frame (MRF) buildings. It is found that the height of a building plays an important role in predicting the fundamental vibration period, compared with the length, width, and time after completion of the building. It is also found that the RC MRF buildings in Taiwan tend to be stiffer than those in the U.S. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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地铁以其快捷、准时、运量大等优点,已成为重要的轨道交通形式,但由此引起的环境振动问题日益突出。针对杭州市地铁3号线曲线地段的某中学建设工程,利用有限元软件ABAQUS,对车辆-普通整体道床轨道系统的竖向耦合模型进行振动响应分析,得到考虑轨道高低不平顺影响的轨道振动源强。应用有限元软件MIDAS GTS/NX,建立双孔平行曲线盾构隧道-土-桩-建筑物系统的三维有限元模型。以轨道支点力作为激励对地铁列车运行时的隧道-土-桩-建筑物系统的振动响应进行计算,研究地铁振动波在地层中的传播规律和建筑物的动力响应特性。根据相关环境振动控制标准对建筑物的振动舒适性进行评价。结果表明:轨道加速度和扣件动支点力的最大值分别约为40 m/s2和30 kN;地层和建筑物的振动以竖向为主,水平Y向振动略大于水平X向振动;地面加速度随着距隧道中心线距离的增加而逐渐衰减;各建筑物楼层的振动主频位于16~40 Hz;部分建筑物楼层的振动响应水平已超出了规范的限值要求,建议对地铁轨道或建筑物采取适当的减振措施。 相似文献
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传统低层建筑砌体结构动力特性分析中,易受到外界环境的干扰,砌体结构的完整性欠缺,导致动力特性分析的准确度较低。为提高低层建筑砌体结构的抗震性能,提出地震作用下低层建筑砌体结构的动力特性分析方法。首先利用低层建筑砌体结构反应自功率谱,完成砌体结构的自振频率辨认;然后通过941B型超低频率测振仪测试自振频率,筛出振动波形中噪声干扰的区域,获取时域波形和频域波形;最后依据时域波形和频域波形塑造低层建筑砌体三维精细化模型,在该模型基础上,通过子空间迭代算法获取低层建筑砌体结构的模拟结果,分析地震作用下芯柱、圈梁等构造措施对建筑砌体结构动力特征的影响,完成砌体结构的动力特性分析。实验结果表明,利用所提方法对地震作用下低层建筑砌体结构的动力特性进行分析,得到的分析结果准确度较高。 相似文献
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In this paper, a field experiment was carried out to study train-induced environmental vibrations. During the field experiment, velocity responses were measured at different locations of a six-story masonry structure near the Beijing-Guangzhou Railway and along a small road adjacent to the building. The results show that the velocity response levels of the environmental ground and the building floors increase with train speed, and attenuate with the distance to the railway track. Heavier freight trains indu... 相似文献
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由地震等自然灾害引发的等级多变强随机振动会对大跨度钢管混凝土柱结构产生较大的破坏,造成相关建筑全结构寿命周期性衰减。提出一种随机振动下大跨度钢管混凝土柱结构的抗震性测试方法,在等级多变强随机振动的情况下,设计测试模型,利用信号的协方差矩阵将振动信号与噪声进行分离,通过计算振动信号的强度、后验密度及权值系数等对振动信号进行预处理,获取单一寿命衰减参数;在此基础上引入粒子群算法,求解大跨度钢管混凝土柱结构寿命衰减抑制周期,判断其抗震性。实验结果表明,按照大跨度钢管混凝土柱结构寿命衰减抑制周期的判断方法,可实现对相关建筑结构在等级多变强随机振动下的抗震性测试。 相似文献
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The knowledge of fundamental frequency and damping ratio of structures is of uppermost importance in earthquake engineering, especially to estimate the seismic demand. However, elastic and plastic frequency drops and damping variations make their estimation complex. This study quantifies and models the relative frequency drop affecting low‐rise modern masonry buildings and discusses the damping variations based on two experimental data sets: Pseudo‐dynamic tests at ELSA laboratory in the frame of the ESECMaSE project and in situ forced vibration tests by EMPA and EPFL. The relative structural frequency drop is shown to depend mainly on shaking amplitude, whereas the damping ratio variations could not be explained by the shaking amplitude only. Therefore, the absolute frequency value depends mostly on the frequency at low amplitude level, the amplitude of shaking and the construction material. The decrease in shape does not vary significantly with increasing damage. Hence, this study makes a link between structural dynamic properties, either under ambient vibrations or under strong motions, for low‐rise modern masonry buildings. A value of 2/3 of the ambient vibration frequency is found to be relevant for the earthquake engineering assessment for this building type. However, the effect of soil–structure interaction that is shown to also affect these parameters has to be taken into account. Therefore, an analytical methodology is proposed to derive first the fixed‐base frequency before using these results. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Philippe Gueguen Véronique Jolivet Clotaire Michel Anne-Sophie Schveitzer 《Bulletin of Earthquake Engineering》2010,8(2):327-338
Over recent years there has been a growing interest in the building frequency analysis for earthquake and structural engineering
fields using ambient vibrations. Simultaneously, velocity measurements with LASER remote sensing techniques have gained more
interest for several applications. This paper details the comparison of the frequency analysis obtained using sensitive velocimeter
sensor and coherent LIDAR (Light Detection and Ranging) sensor, and applied to one RC existing building. Ambient vibrations
recordings were processed using the Frequency Domain Decomposition method for defining the frequencies and mode shapes of
the building target, while LASER remote sensing approach used coherent LIDAR method for velocity and frequency measurement.
The results of the two systems are discussed. A good agreement is observed, which let us conclude on the ability of the coherent
LIDAR to assess the frequency of existing buildings for structural and earthquake engineering fields at long range and without
any retroreflector on the structure. 相似文献
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