平转耦联隔震结构的动力特性及地震作用效应计算分析     

李向真  向伟明  梁萍 《世界地震工程》2004,20(3):119-122

建立了平转耦联隔震结构地震作用效应的计算方法，并在此基础上对结构的动力性能及隔震效果作出了比较和分析。  相似文献   

Rainfall interception by an isolated evergreen oak tree in a Mediterranean savannah   总被引：1，自引：0，他引：1  

T. S. David  J. H. C. Gash  F. Valente  J. S. Pereira  M. I. Ferreira  J. S. David 《水文研究》2006,20(13):2713-2726

Redistribution of ground‐level rainfall and interception loss by an isolated Quercus ilex tree were measured over 2 years in a Mediterranean oak savannah. Stemflow, meteorological variables and sap flow were also monitored. Rainfall at ground level was measured by a set of rain‐gauges located in a radial layout centred on the tree trunk and extending beyond the crown limits. Interception loss was computed as the difference between the volume of rainwater that would reach the ground in the absence of the tree and the volume of water that actually fell on the ground sampling area (stemflow included). This procedure provided correct interception loss estimates, irrespective of rainfall inclination. Results have shown a clear non‐random spatial distribution of ground‐level rainfall, with rainwater concentrations upwind beneath the crown and rain‐shadows downwind. Interception loss amounted to 22% of gross rainfall, per unit of crown‐projected area. Stand interception loss, per unit of ground area, was only 8% of gross rainfall and 28% of tree evapotranspiration. These values reflect the low crown cover fraction of the stand (0·39) and the specific features of the Mediterranean rainfall regime (predominantly with few large storms). Nevertheless, it still is an important component of the water balance of these Mediterranean ecosystems. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

基于建筑抗震设计规范的设计用地震动分析   总被引：1，自引：0，他引：1  

裴星洙  廖述清  张立  北村春幸 《世界地震工程》2006,22(2):154-160

首先利用我国《建筑抗震设计规范》(GB 50011-2001)中的地震影响系数曲线,制成适合于我国抗震设计规范的人工地震波形,然后使用该人工波和日本现行设计用地震动,对隔震结构进行地震响应分析,最后由地震响应结果对所提出的模拟设计用地震动大小进行评价,得到一些有意义结论,供抗震设计人员在设计时参考。  相似文献   

Deep-water sediments and evolution of the Lower Triassic Xikou Formation in southwestern Fujian, China   总被引：1，自引：1，他引：0  

Peijun Li  Quanlin Hou  Shu Sun  Jiliang Li 《中国科学D辑(英文版)》1998,41(6):639-647

The Lower Triassic Xikou Formation in southwestern Fujian, China is a set of complex deep-water sediments which includes turbidites, sandy contourites and isolated olistoliths. Five facies and seven subfacies are recognized in the deep-water turbidites, which are considered to belong to five facies associations of upper, middle and lower fans, respectively. The sandy contourites, which occur within turbidites as isolated thin layers with structures of traction current, are formed by reworking turbidites. They occur in discrete units, not as a part of a vertical sequence of structures, such as Bouma sequence. Paleocurrent directions derived from sandy contourites are perpendicular to or at a large angle of those derived from turbidites. In some areas, within the Formation there exist large oolitic limestone blocks slided from shallow sea. The temporal-spatial distribution of three types of sediments mentioned above and the related evidences could indicate that a passive continental margin from shallow sea to bathyal-abyssal region, dipping toward southeast, once occurred in study area during the early Triassic. The early Triassic represents a period of sealevel uprising. The uprising of sea level and the development of isolated olistoliths probably imply gradual shrinking of an ocean basin at that time. Project supported by the National Natural Science Foundation of China (Grant Nos. 49490011, 49702036).  相似文献   

变刚度半主动结构振动控制的试验研究   总被引：8，自引：0，他引：8  

李敏霞  刘季 《地震工程与工程振动》1998,18(4):90-95

本文成功地完成了五层框架的变刚度半主动结构振动控制的模拟地震振动试验,这不仅是我国的第一个变刚度半主动结构振动控制的试验,在国际上也是少数几例之一。本文介绍了试验系统的构成,试验内容,试验结果的分析及试验结论等。  相似文献   

摆,油阻尼器减振的试验研究     

郭迅  张敏政 《地震工程与工程振动》1996,16(1):122-128

高柔结构在地震或风荷载作用下会产生很大的振动，本文提出一种控制高柔结构振动的新方法－－摆、油阻尼器体系，并在振动台进行了模拟试验，结果表明：该方法可使结构振动位移幅值减小５０％，在试验中变换了体系的各有关参数，研究了摆长，质量比，碰击间隙对减振效果的影响，文中详细研究了油阻尼器的工作过程及减振机理，从理论上初步分析了摆，油阻尼器体系减振原因，提出了可供实际设计参考的方法和原则。  相似文献   

台湾海峡7.3级地震强震记录分析     

谢建清  陈少坚 《华南地震》1996,16(3):21-26

介绍了１９９４年９月１６日台湾海峡发生了７．３级强烈地震时，在汕头国际大酒店内的强震加速度记录，这是我国在软弱地基高层建筑结构（２６层）上首次获得的７级以上的强震加速度记录，文中介绍了对记录分析得到的最大加速度（及积分成速度，位移）振动周期等基本结果。  相似文献   

Analysis of train-induced vibrations and vibration reduction schemes above and below critical Rayleigh speeds by finite element method   总被引：6，自引：0，他引：6  

Shen-Haw Ju  Hung-Ta Lin 《Soil Dynamics and Earthquake Engineering》2004,24(12):993-1002

This paper simulates soil vibration under the train speed below and over the soil Rayleigh speed using the three-dimensional finite element method. Two vibration isolation schemes were studied including the soil improvement around the railway and the concrete slab constructed between the rail and soil. Numerical results indicate that the vibration increases considerably and decays slowly when the train speed exceeds the soil Rayleigh speed. The wave direction and dominant frequencies are the simple functions of the train speed, the soil Rayleigh speed and the train compartment length. When the train speed exceeds the shear wave speed, the vibration magnitude is critical and not sensitive to the train speed. To reduce this vibration, the two isolation schemes investigated in this study are useful for the train speed over the soil Rayleigh speed, but they are not efficient for the train speed below the soil Rayleigh speed.  相似文献   

基于单质点体系的多层隔震结构设计方法     

杨巧荣 《地震工程与工程振动》2003,23(4):144-149

本文针对多层隔震结构提出了适合工程技术人员使用的基于单质点体系建立的等价线性化设计方法，这种设计方法结合我国现行的建筑抗震设计规范，将上部结构简化成单质点体系，基于最大设计位移进行地震反应分析，是一种实用设计法。文中以地下1层、地上5层的多层框架结构体系为例进行了分析，并与时程分析法计算结果进行了对比，结果显示本文提出的设计计算方法具有计算简便，计算精度符合工程应用的特点。  相似文献   

单层柱面网壳的粘滞阻尼器减振分析   总被引：6，自引：0，他引：6  

范峰  沈世钊 《世界地震工程》2003,19(2):27-32

采用粘滞阻尼器减振系统对单层柱面网壳的减振效果进行了较为系统的分析，分别考虑了阻尼系数C0、结构自身阻尼比ζ、屋面质量和结构自身刚度对结构减振系数δ的影响，同时考察了设置阻尼器的数目以及阻尼器的位置的影响。通过较大规模参数化分析，基本了解了粘滞阻尼器减振系统在单层柱面网壳中的减振规律。  相似文献