Inelastic displacement ratios for evaluation of existing structures     

Jorge Ruiz‐García  Eduardo Miranda 《地震工程与结构动力学》2003,32(8):1237-1258

Results of a detailed statistical study of constant relative strength inelastic displacement ratios to estimate maximum lateral inelastic displacement demands on existing structures from maximum lateral elastic displacement demands are presented. These ratios were computed for single‐degree‐of‐freedom systems with different levels of lateral strength normalized to the strength required to remain elastic when subjected to a relatively large ensemble of recorded earthquake ground motions. Three groups of soil conditions with shear wave velocities higher than 180m/s are considered. The influence of period of vibration, level of lateral yielding strength, site conditions, earthquake magnitude, distance to the source, and strain‐hardening ratio are evaluated and discussed. Mean inelastic displacement ratios and those associated with various percentiles are presented. A special emphasis is given to the dispersion of these ratios. It is concluded that distance to the source has a negligible influence on constant relative strength inelastic displacement ratios. However, for periods smaller than 1s earthquake magnitude and soil conditions have a moderate influence on these ratios. Strain hardening decreases maximum inelastic displacement at a fairly constant rate depending on the level of relative strength for periods of vibration longer than about 1.0s while it decreases maximum inelastic displacement non‐linearly as the period of vibration shortens and as the relative‐strength ratio increases for periods of vibration shorter than 1.0s. Finally, results from non‐linear regression analyses are presented that provide a simplified expression to be used to approximate mean inelastic displacement ratios during the evaluation of existing structures built on firm sites. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Seismic risk assessments and GIS technology: applications to infrastructures in the Friuli–Venezia Giulia region (NE Italy)     

Raffaella Codermatz  Rinaldo Nicolich  Dario Slejko 《地震工程与结构动力学》2003,32(11):1677-1690

This paper illustrates the seismic risk preliminary estimates of two different groups of structures located on the territory of the Friuli–Venezia Giulia region (NE Italy) : the first group includes some special industrial plants, and the second group includes bridges and tunnels belonging to the regional highway network. The part of the study on special industrial plants tries to evaluate the degree of expected damage, taking into account their structural typology and ground shaking expressed in terms of macroseismic intensity. The second part of the study is an application of the HAZUS methodology to the tunnels and bridges of a highway network: the combination of expected ground shaking and the construction characteristics lead to very different risk levels, especially when considering the bridges. The resulting damage levels to bridges and tunnels are still only indicative because of the fragility curves used in the evaluations: they were developed for existing bridge and tunnel structural typologies in the U.S.A. Moreover, both examples show the power of GIS technology in storing, elaborating, and mapping spatial data. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

论层序地层学与含油气系统在油气勘探中的联系——以鄂尔多斯中生代盆地为例   总被引：10，自引：0，他引：10  

屈红军李文厚  梅志超陈全红 《地质论评》2003,49(5):495-500

虽然层序地层学与含油气系统理论的各自研究对象和研究方法不同，但由于层序地层学研究对象(沉积岩)是含油气系统研究对象(油气)的载体，二者可以由含油气盆地分析有机的结合起来。层序地层分析包含了对含油气系统的地质要素及成藏作用载体的分析，因而沉积层序的组成单元与含油气系统的地质要素有必然的联系：在一个沉积盆地的数个沉积层序中，成熟烃源岩往往是地史中具一定埋深、分布广、厚度大、有机质含量高的凝缩层，这个凝缩层往往是一个构造超层序的最大海(湖)泛面；储集岩往往是成熟烃源岩之上层序的低水位体系域或紧邻成熟烃源岩的高水位体系域；有效盖层为储集岩之上层序的水进体系域及凝缩层；成熟烃源岩之上的沉积层序为上覆岩层；低水位体系域储集岩有可能沿上倾方向尖灭，被层序界面及其上层序的水进体系域岩性圈闭；除构造裂缝外，低水位体系域下切谷可作为油气向上运移通道；一个含油气系统往往跨越不同的沉积层序甚至构造超层序。  相似文献   

将EPSW与MAPGIS集成进行管线测量和管理的探讨——EPSW和MAPGIS在沙钢管网信息系统中的应用     

彭绍才  程新文 《北京测绘》2003,(3):21-24

随着测量和地理信息技术的发展,管网信息系统的应用越来越广泛,并日趋受到人们的重视。数据采集和管理的分离,无疑会浪费大量的人力、物力和财力。本文以张家港市沙钢集团管网建设为例,介绍了EPSW(Electronic plane-table Surveying and Mapping System for Windows)电子平板测绘软件和MAPGIS结合进行管网的数据采集和管理的设想。  相似文献   

次天气尺度及中尺度暴雨系统研究进展   总被引：37，自引：8，他引：37       下载免费PDF全文

高守亭  赵思雄  周晓平  孙淑清  陶诗言 《大气科学》2003,27(4):618-627

回顾了75年来中国科学院大气物理研究所科研人员在次天气尺度及中尺度暴雨系统领域的研究工作,这些领域主要包括暴雨、中尺度低空急流、低涡、梅雨锋结构及梅雨锋生、对称不稳定和涡层不稳定以及暴雨等灾害天气的天气动力学及数值模拟研究等;总结了在次天气尺度及中尺度暴雨系统研究的不同时期所取得的成就以及这些成就在防止和减轻中尺度暴雨灾害方面所起到的重要作用.  相似文献   

A comparison of three image-object methods for the multiscale analysis of landscape structure   总被引：4，自引：0，他引：4  

Geoffrey J. Hay  Thomas Blaschke  Danielle J. Marceau  Andr Bouchard 《ISPRS Journal of Photogrammetry and Remote Sensing》2003,57(5-6):327

Within the conceptual framework of Complex Systems, we discuss the importance and challenges in extracting and linking multiscale objects from high-resolution remote sensing imagery to improve the monitoring, modeling and management of complex landscapes. In particular, we emphasize that remote sensing data are a particular case of the modifiable areal unit problem (MAUP) and describe how image-objects provide a way to reduce this problem. We then hypothesize that multiscale analysis should be guided by the intrinsic scale of the dominant landscape objects composing a scene and describe three different multiscale image-processing techniques with the potential to achieve this. Each of these techniques, i.e., Fractal Net Evolution Approach (FNEA), Linear Scale-Space and Blob-Feature Detection (SS), and Multiscale Object-Specific Analysis (MOSA), facilitates the multiscale pattern analysis, exploration and hierarchical linking of image-objects based on methods that derive spatially explicit multiscale contextual information from a single resolution of remote sensing imagery. We then outline the weaknesses and strengths of each technique and provide strategies for their improvement.  相似文献   

模块化模糊神经网络的数值预报产品释用预报研究   总被引：13，自引：0，他引：13       下载免费PDF全文

金龙  林熙  金健  李菁 《气象学报》2003,61(1):78-84

综合应用预报量自身时间序列的拓展,数值预报产品和模块化模糊神经网络方法,进行了一种新的数值预报产品释用预报研究。将这种新方法与常规的数值预报产品完全预报(PP)方法进行了对比试验。结果表明,这种模块化模糊神经网络数值预报产品释用预报方法比PP预报方法的预报精度显著提高。并且,通过对预报模型“过拟合”现象的研究发现,这种模块化模糊神经网络的数值预报产品释用预报模型具有很好的泛化性能。  相似文献   

东北大部旱情缓解 粤闽局地暴雨成灾──1997年5月   总被引：1，自引：0，他引：1       下载免费PDF全文

徐良炎 《气象》1997,23(8):62-63

东北大部旱情缓解粤闽局地暴雨成灾—１９９７年５月—徐良炎（国家气候中心，北京１０００８１）５月份，东北大部、华北北部及黄淮等地普降喜雨，旱情缓解；西北东部、华北西部等地降水偏少，旱情持续或发展。南方大部地区雨水比较调匀，无大范围旱涝发生，但华南局地遭...  相似文献   

湘鄂赣二叠纪岩相古地理研究   总被引：4，自引：0，他引：4  

牟传龙  丘东洲  王立全  万方 《沉积与特提斯地质》1997,17(6):1-21

湘鄂赣二叠纪沉积盆地是在华南陆块基础上发育而成，具有扬子克拉通北缘被动大陆边缘盆地，扬子克拉通盆地，湘赣板内拉张盆地和华夏克拉通边缘盆地等四类。根据古暴露等标志，建立了各类盆地的沉积层序，并进行了区域对比。  相似文献   

The Organization of Production in High Technology Industries: An Empirical Assessment*     

Audrey E. Clarke  Brian P. Holly 《The Professional geographer》1996,48(2):127-139

Recent attention given to the concept of vertical integration and disintegration of production processes has identified the existence of a continuum, with small, flexibly specialized producers at one end and large, mass production units at the other end. Firms along the continuum constantly strive for the optimum combination of economies of scale and scope. This paper attempts to identify the organizational characteristics of high technology firms in one industrial complex of the U.S. Manufacturing Belt. A principal components analysis is performed on a number of theoretically relevant variables for a sample of high technology establishments in Northeast Ohio. The results indicate that the region contains a variety of organizational forms ranging from isolated workshops to large, vertically integrated assembly plants. These findings conform to expectations derived from recent conceptualizations in the literature. Additional empirical research will further enhance understanding of the processes that shape the organization of production in territorial complexes.  相似文献