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11.
Damage phenomena observed in structures subject to intense seismic events are the result of stiffness and strength degradation. This paper studies the damage assessment of hysteretic degrading structures described by means of the Bouc-Wen model, modified to represent the mechanical degradation induced by severe earthquakes. In order to consider randomness of seismic action, the analysis is performed by adopting a stochastic approach and the Park and Ang damage functional is also evaluated in stochastic way. A parametric analysis is carried out with the aim to analyse the effect of mechanical characteristics and measure parameters of earthquake intensity on seismic response and damage level. Damage spectra are finally obtained and they are used to develop, on the basis of the Performance Based Seismic Design, ductility demand spectra. 相似文献
12.
STEFANO PODESTAgrave 《Journal of Earthquake Engineering》2013,17(3):419-444
In this paper the Author proposes a damage model for the analysis of masonry plates and shells, which is based on an improvement of a previous constitutive model. The modifications introduced, connected to the head joint damage, allow us to study the influence of masonry texture on the damage modes once the mechanical characteristics of the elements constituting the masonry and the results of tests on simple assemblages are known. Having a nonlinear constitutive model is certainly one of the basic elements for understanding the damage mechanisms in masonry buildings. If, in fact, an elastic-linear constitutive model may be used under normal loading conditions, in critical situations it is necessary to model the damage and the dissipation mechanisms that occur between the elements, stone (brick) and mortar, in correlation with their characteristics and kind of masonry. To validate the model a comparison is made between the numerical and experimental results, in the case of tests available in the literature in masonry panels subjected to out-of plane loading and in a real structure through the observation of the damage in Umbria (Italy) surveyed after the 1997 earthquake. 相似文献
13.
Louise Karlskov Skyggebjerg 《History & Technology》2013,29(1):31-57
ABSTRACTIn the 1990s, there was a change in capitalist thinking on environmental issues in many global settings, which materialised in what has been termed corporate environmentalism. Beginning with a history of the moulded fibre egg tray and one of its primary manufacturers, this is a case study of how corporate environmentalism came about and was enacted as a confluence of corporate priorities, environmental concerns, production processes, materials, and the development of new measuring tools. Unlike the many environmental history studies that emphasise the role of NGOs and policy developments, this study begins in the business world. More specifically, it is based in the making of environmental knowledge in the form of life cycle assessments and environmental accounts and in the environmental reframing of materials like moulded pulp and plastic. In this way it is the story of how it became reasonable for a manufacturer of egg trays to choose the slogan, ‘Choose Fibre. Save Nature’. 相似文献
14.
Federico Zaina 《Conservation and Management of Archaeological Sites》2013,15(3):184-206
ABSTRACTThis paper proposes a classification of the risks threatening archaeological sites in southern Iraq and suggests some possible remediation to better preserve them. This has been possible thanks to a research methodology that combines remote sensing and ground control on a sample of 558 sites documented by the Iraqi-Italian QADIS survey project. A three-tier typological framework has been created illustrating the risks jeopardising the cultural heritage of the region. This research showed that the most impacting risks are the ones caused by agricultural activity, despite current narratives which mainly focus on looting and violent destruction. To get at the root of the problem, current laws protecting cultural heritage in Iraq are analysed, as well as how the cultural authorities are organised on the ground. Improving the organisation of the SBAH, engaging the local communities towards the issue of sites’ protection and introducing preventive archaeology are among the solutions proposed. 相似文献
15.
《Conservation and Management of Archaeological Sites》2013,15(4):341-358
AbstractOver the last few decades, conservation work has been conducted by the Department of Antiquities of Jordan (DoA) on the Roman Nymphaeum in Amman. This intervention has taken the form of direct and indirect actions. In this article it will be shown that the conservation works concentrated on reinforcing the structure and reconstructing some architectural features of the building, with little consideration of the techniques and materials used. Intervention actions were mostly poor in terms of their scientific approach, and neither proper planning nor a well-defined methodology existed. This study provides a holistic approach for the evaluation of the state of the conservation of the monument in terms of quality and quantity. Thus, the results could be a valuable source for establishing comprehensive risk mitigation for future restoration work and site management. In addition, establishing practical restoration guidelines could help in developing socio-economic benefits for the community through tourism. 相似文献
16.
北京市生态城市建设能力的机理与综合评价--基于城市化与生态化视角 总被引：7，自引：0，他引：7
基于城市化与生态化两大子系统,从人口与空间城市化、经济城市化、社会城市化、和生态环境水平、生态压力、生态抗逆能力六个层面,构建生态城市建设能力评价的指标体系,运用相关分析、回归分析和主成分分析等方法,对1991-2002年北京市生态城市建设能力机理进行了综合分析与评价。 相似文献
17.
博物馆,档案馆,图书馆被保护环境中气态污染物的监测和分级 总被引：1，自引：1，他引：0
过去几十年,美国普滤公司合作开发了一种可以用来精确评价被保护环境中存在破坏可能性的技术,用来保护珍贵的文物,艺术品及历史档案资料。他们一方面研究开发了能精确评估被保护环境的反应监测仪器和监测技术,另一方面又制订一套新的环境分级标准,使文物保护者了解被保护环境是否是安全的。现把这种文物、档案、图书保存环境的反应监测技术和环境评估的新标准介绍给国内的同行们。 相似文献
18.
医院可达性评价与规划——以江苏省仪征市为例 总被引：5，自引：0，他引：5
医院作为公共服务设施的一个重要组成部分,为居民提供了必不可少的医疗机会,其空间分布以及可达性的优劣,直接影响到居民能接触到医院的机会和方便程度。把可达性的概念引入到医院规划中,利用Mapinfo公司的控件MapX和Borland公司的可视化编程语言Delphi,开发了基于时间最短的路径选择信息系统,生成了医院可达性的等时线图和医院服务范围图,通过该系统可直观的看到区域内任何一点到达同一级医院所花费的最短时间以及通过的路径。以江苏省仪征市的医院为例,运用该系统对医院的可达性进行了评价,并提出了医院的规划方案。 相似文献
19.
甲基三甲氧基硅烷对砂岩石刻封护性能的实验室研究 总被引：1，自引：0，他引：1
谢振斌 《文物保护与考古科学》2008,20(4):10-14
为了解砂岩石刻用甲基三甲氧基硅烷材料封护处理后的各项性能,选择四川省内风化较严重的摩崖造像区的砂岩作为实验样品,采用浸水、酸雾、盐老化、光老化、循环破坏等方法对材料的憎水性、透气性、耐老化性能进行实验测试。试验表明,砂岩样品用甲基三甲氧基硅烷封护处理后其憎水性、耐老化性都有较大的提高,透气性没有太大的改变,半涂样品经循环破坏处理后,表面出现开裂现象。通过研究表明,甲基三甲氧基硅烷材料处理砂岩后其憎水性和耐老化性都较好,但循环破坏实验提示,甲基三甲氧基硅烷材料处理石刻可能对其表面产生负作用,在石刻保护中应慎重使用。 相似文献
20.
游憩价值评估是识别旅游资源经济价值的重要手段.TCM作为传统评估方法,其评估结果的准确性受多种因素影响,其中游憩需求的影响因素对评估结果的影响是尚待解决的关键问题.游客感知价值是影响游憩需求的重要因素,考察其对评估结果的影响是提高评估结果精确性的一种有益尝试.本文以TCM的两种基本模型ZTCM和ITCM为基础,探索不同介入方式下感知价值对评估结果的影响机制.研究表明:感知价值作为自变量介入ZTCM模型后使人均消费者剩余下降了7.3%、游憩价值下降了4.4%,大于它作为中介变量介入ITCM模型后对评估结果的影响,说明感知价值主要通过与旅行花费共同作用对价值评估结果产生影响.这不仅揭示了游客感知价值影响的复杂性,更体现了游憩价值评估体系中考虑游憩需求影响因素的必要性. 相似文献