Studies on wind environment around high buildings in urban areas     

LIU Huizhi  JIANG Yujun  LIANG Bin  ZHU Fengrong  ZHANG Boyin  SANG Jianguo 《中国科学D辑(英文版)》2005,48(Z2)

High buildings or architectural complex in urban areas remarkably distort the urban surface wind fields. As the air flow approaches,local strong wind may appear around the buildings. The strong wind makes the pedestrians on sidewalks, entrances and terrace very uncomfortable and causes the pedestrian level wind environment problem. In this studies, hot-wire wind measurement, wind scouring in wind tunnel and numerical computation were carried out to evaluate the wind environment of tall buildings in the prevailing flow conditions in Beijing areas. The results obtained by three techniques were compared and mutually verified. The conclusions drawn from three approaches agree with each other. Also the advantages and limitations of each method were analyzed. It is suggested that the combination of different techniques may produce better assessment of wind environment around high buildings.  相似文献   

民房震害预测专家评定统计模型的探讨     

徐祥文  黄崇福 《地震研究》1993,16(2):187-192

本文针对专家评定意见有一定伸缩性的特点,将专家意见表示为评定论域上的模糊子集,利用可能性相加原理,对专家意见进行了统计分析,得出综合性的意见。结果表明,利用伸缩性提供的丰富信息,可以较好地总结专家意见。基于几种模型的仿真可靠性分析结果,本文推荐可靠性最高的模型作为城市平房震害预测统计手段。  相似文献   

山东省损毁山体景观影响度分析     

张永伟  ;刘怀念  ;刘元本 《山东地质》2009,(2):24-26

损毁山体严重影响城市和交通沿线景观,景观影响度可作为一个综合指标来反映损毁山体对城市景观的影响程度。应用专家评分综合评判法结合地理信息系统确定景观影响度分级标准,对损毁山体进行景观影响程度的评价与分析,得出景观影响度分类结果,为损毁山体的治理规划和有序整治提供科学依据。  相似文献   

超高层建筑平面控制网竖向传递实践与研究   总被引：2，自引：0，他引：2  

赵小阳  刘业光 《测绘信息与工程》2010,35(4):28-29

分析了超高层建筑平面控制网的建立及竖向传递的方法,介绍了数字正垂在测定超高层建筑倾斜偏差的具体应用,实现了用全站仪法和GPS法来检核控制网竖向传递的精度。  相似文献   

    

Xiaoyun Shao  Weichiang Pang  Chelsea Griffith  Ershad Ziaei  John van de Lindt 《地震工程与结构动力学》2016,45(8):1233-1249

Hybrid simulations of a full‐scale soft‐story woodframe building specimen with various retrofits were carried out as part of the Network for Earthquake Engineering Simulation Research project – NEES‐Soft: seismic risk reduction for soft‐story woodframe buildings. The test structure in the hybrid simulation was a three‐story woodframe building that was divided into a numerical substructure of the first story with various retrofits and a full‐scale physical substructure of the upper two stories. Four long‐stroke actuators, two at the second floor and two at the roof diaphragm, were attached to the physical substructure to impose the simulated seismic responses including both translation and in‐plane rotation. Challenges associated with this first implementation of a full‐scale hybrid simulation on a woodframe building were identified. This paper presents the development and validation of a scalable and robust hybrid simulation controller for efficient test site deployment. The development consisted of three incremental validation phases ranging from small‐scale, mid‐scale, to full‐scale tests conducted at three laboratories. Experimental setup, procedure, and results of each phase of the controller development are discussed, demonstrating the effectiveness and efficiency of the incremental controller development approach for large‐scale hybrid simulation programs with complex test setup. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

    

Fatemeh Jalayer  Hossein Ebrahimian 《地震工程与结构动力学》2020,49(5):434-457

Modelling uncertainty can significantly affect the structural seismic reliability assessment. However, the limit state excursion due to this type of uncertainty may not be described by a Poisson process as it lacks renewal properties with the occurrence of each earthquake event. Furthermore, considering uncertainties related to ground motion representation by employing recorded ground motions together with modelling uncertainties is not a trivial task. Robust fragility assessment, proposed previously by the authors, employs the structural response to recorded ground motion as data in order to update prescribed seismic fragility models. Robust fragility can be extremely efficient for considering also the structural modelling uncertainties by creating a dataset of one-to-one assignments of structural model realizations and as-recorded ground motions. This can reduce the computational effort by more than 1 order of magnitude. However, it should be kept in mind that the fragility concept itself is based on the underlying assumption of Poisson-type renewal. Using the concept of updated robust reliability, considering both the uncertainty in ground motion representation based on as-recorded ground motion and non ergodic modelling uncertainties, the error introduced through structural reliability assessment by using the robust fragility is quantified. It is shown through specific application to an existing RC frame that this error is quite small when the product of the time interval and the standard deviation of failure rate is small and is on the conservative side.  相似文献   

    

Roshanak Omrani  Ralph E. Hudson  Ertugrul Taciroglu 《地震工程与结构动力学》2012,41(12):1609-1634

A new parameter estimation algorithm is described for identifying the stiffness properties of torsionally coupled shear buildings from their linear response due to ambient excitations or during low-amplitude forced-vibration tests. The algorithm is based on the time-domain equations of motion, and yields estimates of the stiffness properties using a measure of the equilibrium of forces acting on each floor over a time interval. The banded structure of the stiffness matrix — a property intrinsic to torsion-shear buildings — is exploited to decompose the initial inverse problem into several problems of reduced size. This decomposition allows the identification of lateral and torsional stiffnesses of individual stories, independent of the others. The algorithm utilizes vibration data where input excitation is known/measured, which is typical for forced-vibration tests and earthquakes. If the ambient vibrations of the structure are adequately uncorrelated to the (unknown) external forces that induce such vibrations, then the algorithm can also be modified for output-only system identification. The proposed algorithm is verified — and its various attributes are investigated — using simulation data from the ‘Analytical Phase I’ of the IASC (International Association for Structural Control)-ASCE (American Society of Civil Engineers) benchmark studies. The companion article is devoted to the algorithm's application to experimental data, using data from the ‘Experimental Phase’ of the same benchmark studies. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

    

Praveen K. Malhotra 《地震工程与结构动力学》1999,28(11):1309-1326

Ground motions affected by directivity focusing at near-field stations contain distinct pulses in acceleration, velocity, and displacement histories. For the same Peak Ground Acceleration (PGA) and duration of shaking, ground motions with directivity pulses can generate much higher base shears, inter-storey drifts, and roof displacements in high-rise buildings as compared to the 1940 El Centro ground motion which does not contain these pulses. Also, the ductility demand can be much higher and the effectiveness of supplemental damping lower for pulse-like ground motions. This paper presents a simple interpretation of the response characteristics of three recorded and one synthetic near-field ground motions. It is seen that for pulse-like ground motions—similar to any other ground motion—the Peak values of Ground Acceleration, Velocity, and Displacement (PGA, PGV and PGD) are the key response parameters. Near-field ground motions with directivity effects tend to have high PGV/PGA ratio, which dramatically influences their response characteristics. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

隋唐 · 安得广厦千万间          下载免费PDF全文

冯锐 《地震科学进展》2024,29(7):483-496

隋唐时期的史载地震主要在关中地区,显现了秦岭南侧存在一条北西向的石泉—房县活动断裂带。地震活动和房屋抗震一直是社会关注的大事,以蓟县独乐寺为典型代表,重点介绍了唐代木结构建筑的抗震技术：地基坚固和均匀、木结构的隔震机制、筒体结构的强抗震性能、斗拱构件的阻尼系统,都对后世的技术发展产生了深刻影响。在现代建筑方面,介绍了地震区划的基本原则,分析了农村藏式民居的弱点和改进措施,讨论了城市建筑的3种抗震结构及今后的发展方向。  相似文献   

    

Keri L. Ryan  Anil K. Chopra 《地震工程与结构动力学》2002,31(1):33-54

An approximate method for linear analysis of asymmetric‐plan, multistorey buildings is specialized for a single‐storey, base‐isolated structure. To find the mode shapes of the torsionally coupled system, the Rayleigh–Ritz procedure is applied using the torsionally uncoupled modes as Ritz vectors. This approach reduces to analysis of two single‐storey systems, each with vibration properties and eccentricities (labelled ‘effective eccentricities’) similar to corresponding properties of the isolation system or the fixed‐base structure. With certain assumptions, the vibration properties of the coupled system can be expressed explicitly in terms of these single‐storey system properties. Three different methods are developed: the first is a direct application of the Rayleigh–Ritz procedure; the second and third use simplifications for the effective eccentricities, assuming a relatively stiff superstructure. The accuracy of these proposed methods and the rigid structure method in determining responses are assessed for a range of system parameters including eccentricity and structure flexibility. For a subset of systems with equal isolation and structural eccentricities, two of the methods are exact and the third is sufficiently accurate; all three are preferred to the rigid structure method. For systems with zero isolation eccentricity, however, all approximate methods considered are inconsistent and should be applied with caution, only to systems with small structural eccentricities or stiff structures. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献