Interaction between cladding and structural frame observed in a full‐scale steel building test     

Taichiro Okazaki  Masayoshi Nakashima  Keiichiro Suita  Tomohiro Matusmiya 《地震工程与结构动力学》2007,36(1):35-53

Interaction between the external wall cladding and the seismic load resisting frame was examined in a full‐scale cyclic loading test of a three‐storey steel building structure. The building specimen had Autoclaved Lightweight Concrete (ALC, also designated as Autoclaved Aerated Concrete) panels installed and anchored to the structural frame as external wall cladding, using a standard Japanese method developed following the 1995 Kobe earthquake. ALC panelling is among the most widely used material for claddings in Japan. In the test, the ALC panel cladding contributed little to the stiffness and strength of the overall structure, even under a very large storey drift of 0.04 rad. No visible damage was noted in the ALC panels other than minor cracks and spalling of the bottom of the panels in the first storey. Consequently, in a Japanese steel building with properly installed ALC panel cladding, the structural frame is likely to be little affected by its cladding, and the ALC panels are capable of accommodating the maximum storey drift generally considered in structural design without sustaining discernible damage. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Mapping the spatial variation of soil water content at the field scale with different ground penetrating radar techniques   总被引：2，自引：0，他引：2  

L. Weihermüller  J.A. Huisman  S. Lambot  M. Herbst  H. Vereecken 《Journal of Hydrology》2007,340(3-4):205-216

Two ground penetrating radar (GPR) techniques were used to estimate the shallow soil water content at the field scale. The first technique is based on the ground wave velocity measured with a bistatic impulse radar connected to 450 MHz ground-coupled antennas. The second technique is based on inverse modeling of an off-ground monostatic TEM horn antenna in the 0.8–1.6 GHz frequency range. Data were collected on a 8 by 9 m partially irrigated intensive research plot and along four 148.5 m transects. Time domain reflectometry, capacitance sensors, and volumetric soil samples were used as reference measurements. The aim of the study was to test the applicability of the ground wave method and the off-ground inverse modeling approach at the field scale for a soil with a silt loam texture. The results for the ground wave technique were difficult to interpret due to the strong attenuation of the GPR signal, which is related to the silt loam texture at the test site. The root mean square error of the ground wave technique was 0.076 m³ m⁻³ when compared to the TDR measurements and 0.102 m³ m⁻³ when compared with the volumetric soil samples. The off-ground monostatic GPR measured less within-field soil water content variability than the reference measurements, resulting in a root mean square error of 0.053 m³ m⁻³ when compared with the TDR measurements and an error of 0.051 m³ m⁻³ when compared with the volumetric soil samples. The variability between the two GPR measurements was even larger with a RSME of 0.115 m³ m⁻³. In summary, both GPR methods did not provide adequate spatial information on soil water content variation at the field scale. The main reason for the deviating results of the ground wave method was the poor data quality due to high silt and clay content at the test site. Additional reasons were shallow reflections and the dry upper soil layer that cannot be detected by the ground wave method. In the case of off-ground GPR, the high sensitivity to the dry surface layer is the most likely reason for the observed deviations. The off-ground GPR results might be improved by using a different antenna that allows data acquisition in a lower frequency range.  相似文献   

新疆两次强震前后地震视应力变化   总被引：2，自引：0，他引：2  

孙燕萍  史勇军 《地震地磁观测与研究》2007,28(4):20-28

选取了喀什数字地震台记录的喀什及周边地区地震的宽频带波形资料,分析处理了2001～2005年Ms 3.5以上地震164次,通过数字地震波谱计算了标量地震矩和地震辐射能量,从而进行了视应力的计算.给出了巴楚-伽师Ms 6.8和乌什Ms 6.3强震前后视应力的时序变化情况,发现其视应力均表现出震前低应力阶段-主震前的逐渐上升-震后逐渐恢复的动态变化过程,即地震的孕震-发震-震后调整的阶段性变化特征.这一结果可为喀什及周边地区今后进行地震预测预报研究提供参考依据,对该区开展数字地震方面的研究也有所帮助.  相似文献   

大气数值模式空间分辨率的确定方法     

朱禾  孙岚  廖洞贤 《大气科学》2007,31(3):410-417

集中讨论了如何决定大气数值模式空间分辨率的问题。首先, 给出模式分辨率的定义和模式各方程都应满足的不等式，并在此基础上，用尺度分析和单波的方法推出模式水平和垂直分辨率的预估公式。还给出针对一般模式，以预估公式作基础，选择一系列分辨率，用比较试验，结合大气结构特点，最终确定模式分辨率的方法。并用浅水模式进行了水平分辨率的试验。  相似文献   

近50年我国持续性暴雨的统计分析及其大尺度环流背景   总被引：40，自引：3，他引：40  

鲍名 《大气科学》2007,31(5):779-792

根据1951～2005年中国大陆730个台站的逐日降水资料和持续性暴雨发生的特点, 提出了采用局地持续性暴雨和区域持续性暴雨事件的两种客观定义来描述和统计近50年我国持续性暴雨时空特征及其变化。单站逐日降水量连续三天或三天以上均大于等于50 mm为一次局地持续性暴雨；区域持续性暴雨指在一定区域范围内连续三天降水量总和大于等于100 mm且每天降水量大于等于25 mm的面积超过某一阈值 (详细定义见正文）。根据局地持续性暴雨定义, 指出: 近50年中国局地持续性暴雨事件主要发生在江南和华南地区, 发生季节以6月为最多；根据区域持续性暴雨定义, 统计分析了四类典型的区域持续性暴雨类型, 分别是: 渤海辽西型、北方经向型、南方锋面型和华南低压型。其中南方锋面型又可根据持续性暴雨易发生的地理位置分为江淮型、江南型和华南型三种。对这六类区域持续性暴雨的历史个例进行同比分析, 研究了不同类型持续性暴雨发生的季节性和年际变化,以及它们在大尺度环流背景方面的共性特征。  相似文献   

基于降水气候强迫的一种地表径流估计方法   总被引：2，自引：0，他引：2  

刘晶淼  丁裕国  周秀骥  李云 《气象学报》2004,62(3):285-293

文中从地表水分平衡的物理机制出发 ,引进降水概率统计分布理论 ,推导出一种由降水气候强迫形成的次网格尺度非均匀径流率计算方法。应用于mosaic方案 ,可进一步计算区域平均径流及产流和汇流。试验证明 ,对于不同物理性质的地表而言 ,由于其土壤入渗能力的差异 ,相同降水气候强迫所能生成的径流量及其相对比值是不同的 ,例如干旱区与湿润区就有很大差异。同时 ,不同空间分布概率的降水量 ,不同站点的地表性质、土壤水力学条件等物理因素的千变万化 ,可使径流特征的空间分布具有很大变异性。因上述各种因素的综合影响 ,由降水气候强迫所形成的地表径流具有特定的非均匀分布是必然的。文中用实测资料验证了其可靠性与可行性  相似文献   

利用卫星轨迹交叉点标定CHAMP卫星加速度计数据     

徐天河  杨元喜 《武汉大学学报(信息科学版)》2004,29(11):955-959

基于能量守恒方程给出了利用卫星轨迹交叉点标定CHAMP卫星加速度数据的基本原理和方法 ,并给出了其严密的积分公式及其离散化形式。为了控制加速度数据的扰动异常 ,建议采用抗差估计求解参数值 ,并基于实测的CHAMP卫星加速度计数据进行了计算与比较 ,验证了该方法的有效性  相似文献   

电子地图中居民地的多尺度显示     

宋国民贾奋励  王光霞 《测绘学院学报》2004,21(1):57-60

探讨了多尺度的含义，并将居民地多尺度表达的研究限定在详细程度的变化上；阐述了电子地图中居民地多尺度表达的基本原理，即在保持原图的分布特征和疏密对比的情况下按照居民地自身的分类分级和重要性程度进行一定数量的取舍；建立了居民地多尺度显示的模型，根据此模型提出了采用二级邻近点判别法结合Voronoi图进行居民地要素的显示等级设置的方法，并进行了相应的实验，结果表明该方法对居民地的分布特征、密度对比和延伸方向均能较好的保持。  相似文献   

虚拟地形建模中地物与地形匹配的算法研究   总被引：1，自引：0，他引：1  

刘宁  许敏 《测绘学院学报》2004,21(3):215-218,221

对于大比例尺条件下的地形环境仿真而言，采用贴2维纹理的方式表示地物已远远不能满足定位精度和可视化效果的需要，因为每个地物都是一个清晰可辨的3维实体了。在这种情况下地物模型能否与地形模型相匹配(即虚拟场景中的地物既不悬于地表之上也不陷入地表之下)将直接关系到视觉感受的逼真程度，以及在虚拟场景中对目标实施打击的精确程度。文中就如何实现地物模型与地形模型在数据层次上的匹配提出了一个解决方案，并对具体算法进行了详细阐述。实验结果表明了算法的正确性和实用性，由此说明匹配方案较为行之有效。  相似文献   

NUMERICAL SIMULATION OF EXTREMELY HEAVY RAIN AND MESO-β SCALE LOW VORTEX IN INVERTED TYPHOON TROUGH^*          下载免费PDF全文

JIANG Yongqiang  WANG Changyu  ZHANG Weihuan  CHEN Zhongyi 《Acta Meteorologica Sinica》2004,18(2):195-210

Large-scale and mesoscale analyses are made for extremely heavy rain(EHR) and meso-β scale low vortex(MSLV) in Jiading District of Shanghai Municipality during 6-7 July 2001.It is shown that the EHR forms in the situation of northern westerly trough linking together with southern inverted typhoon trough at northwest side of the West Pacific Ocean subtropical high. Numerical simulation is made using a 21-layer improved REM(regional η coordinate model) for this course.The results show that the precipitation forms earlier than MSLV.and the strong convergence in wind velocity mate(WVM) triggers the strong precipitation.The formative reasons of WVM.especially the weak wind velocity center are discussed,and the formative mechanisms of the MSLV and EHR are discussed using high spatial and temporal resolution modeloutput physical fields.The results show that the heavy rain releases latent heat and warms the air column,and enhances the low level positive vorticity that existed before.Then it causes the formation of MSLV.There is a positive feedback mechanism between low vortex and precipitation,so CISK must be an important mechanism.  相似文献