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21.
Nikos D. Lagaros 《Bulletin of Earthquake Engineering》2007,5(3):425-442
The objective of this study is to perform life-cycle cost analysis on three design practices namely weak ground storey, short
and floating columns and their combinations. Life-cycle cost analysis is recognized as the only suitable tool for assessing
the structural performance when the structure is expected to be functional for a long period of time. Life-cycle cost analysis
is considered in this study assessing the behaviour of the three design practices against earthquake hazard. Although, a number
of checks are performed in order to reduce the influence of these design practices on the seismic behaviour of reinforced
concrete (RC) framed structures, it was found that the total life-cycle cost of partially infilled RC designs is significantly
increased compared to that of the fully infilled one. Through the test example examined in the framework of this study general
conclusions are obtained regarding the behaviour of the three design practices. 相似文献
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本系统讨论了土木工程结构的主动控制和混合控制设备的构造和性能及其实际应用的效果；对一般非线性优化控制方法及其效用做了分析介绍；对当前土木工程结构控制研究中存在的困难和问题以及今后的发展趋势进行了分析讨论和展望。 相似文献
24.
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
25.
Risk assessment of the impact of pyroclastic currents on the towns located around Vesuvio: a non-linear structural inverse analysis 总被引：2，自引：0，他引：2
L.?NunzianteEmail author M.?Fraldi L.?Lirer P.?Petrosino S.?Scotellaro C.?Cicirelli 《Bulletin of Volcanology》2003,65(8):547-561
In a.d. 79, the catastrophic eruption of Vesuvio, which later was described in two famous letters by Pliny the Younger to Tacitus the Historian, destroyed Pompeii, Hercolaneum, Oplontis and Stabiae, resulting in many thousand of victims. After a few hours of the eruption, the several-kilometre-high volcanic column began to collapse, provoking strong air shocks as well as destructive pyroclastic density currents, which travelled down the volcano slopes. In 2000, an archaeological excavation survey, which was performed on the east slope of the volcano in the Terzigno–Vesuvio area at a distance of about 5 km from the vent, brought to light the ruins of several Roman villas that were completely destroyed by these currents during the a.d. 79 eruption. The present paper proposes a new structural analysis, which starts from the study of the damage produced on partially collapsed masonry walls, and determines the dynamic pressures of the currents that overran this site. The non-linear structural analysis, which is based on strength values obtained by means of experimental tests, is of the 'inverse type' and takes into account the limit behaviour of the ancient Roman masonry. The values of the dynamic pressures that were capable of producing the collapse of the masonry walls were obtained by utilising a modern limit analysis theory. The obtained results show that dynamic pressures of a few kPa (1–5) were able to cause masonry buildings to collapse. These values are consistent with those proposed in some of the latest volcanological studies made by numerical simulations of pyroclastic flow propagation. It is shown here that these dynamic pressures are even able to determine the collapse of both modern reinforced concrete and masonry wall buildings that are largely present in the area. Therefore, in possible future eruptions, dynamic pressures of this magnitude would flatten a large urbanised area, where ~700,000 people are currently living. The obtained results give a better definition of both the risk to pyroclastic currents in possible Vesuvio eruptions and provide new guidelines for construction in the neighbouring zones.Editorial responsibility: A. Woods 相似文献
26.
GIS-based hazard mapping and zonation of debris flows in Xiaojiang Basin,southwestern China 总被引：11，自引：0，他引：11
Y.?P.?HeEmail author H.?Xie P.?Cui F.?Q.?Wei D.?L.?Zhong J.?S.?Gardner 《Environmental Geology》2003,45(2):286-293
Debris flow sites were identified at 140 locations in the Xiaojiang Basin in Yunnan province, southwestern China. Their spatial distribution and catchment characteristics are described in detail on the basis of previous research, air photo interpretation, field investigation and mapping using Geographical Information Systems (GIS). Using a statistical approach, a quantitative model of hazards assessment and zonation was developed through synthesis analysis of basin areas, gradients, and the relative reliefs of these debris flow sites. In terms of debris flow hazard assessment, areas within the Xiaojiang Basin can be classified as severe, heavy and light hazard regions. 相似文献
27.
Groundwater surveys were performed by detailed(around 300 sites) grid-analysis of water temperature, pH, redox potential, electrical conductivity, 222Rn, alkalinity and by calculating the pCO2, throughout the Ciampino and Marino towns in the Alban Hills quiescent volcano (Central Italy). Following several episodes of dangerous CO2 exhalation from soils during the last 20 years and earlier ashistorically recorded, the work aimed at assessing the Natural Gas Hazard (NGH) including the indoor-Rn hazard. The NGH was defined as the probability of an area to become a site of poisonous peri-volcanic gas exhalations from soils to the lower atmosphere (comprising buildings). CO2 was found to be a ``carrier' for the other poisonous minor and in trace components (HsS, CH4, 222Rn, etc.). This assessment was performed by extrapolating in the aquifer CO2 and 222Rn conditions, and discriminating sectors where future CO2 flux in soils as well as indoor-Rn measurements have to be noted. A preliminary indoor-Rn survey was performed at about 200 sites. The highest values were found in the highest pCO2 and high 222Rn values in groundwater. This indicates convection and enhanced permeability in certain sectors of the main aquifer, i.e., along the bordering faults and inside the gas-trap of the Ciampino Horst., where ``continuous gas-phase micro-macro seepage mechanism' is invoked to explain the high peri-volcanic gases flux. 相似文献
28.
29.
This work studies the effects of long human habitation on site geotechnical conditions. It is focused on the city of Zefat that is located on the borders of the Dead Sea Transform in northern Israel. The city of Zefat, suffered severe damage and loss of life in historical earthquakes, as a consequence of earthquake induced landslides (EILS). In this work we evaluate the current EILS hazard for the city of Zefat using a GIS-based regional Newmark analysis, with calibration of the calculated Newmark displacement (representing EILS hazard) using maps of field evidence and historical documents testifying to slope instability that occurred in historical earthquakes.
We found that the core city of Zefat is built on a layered anthropogenic material, few meters deep which, was deposited as a result of more than 2000 years of human habitation. The anthropogenic material is mechanically weak, susceptible to slope failure and to amplification of seismic-shaking. It is responsible for the city's devastation in historical earthquakes and it is the source for the current high seismic hazard as well.
Our model shows that earthquakes of magnitudes (Mw) 5, 6 and 7 at distances of up to 10 km, 50 km and more than 100 km, respectively, are likely to induce landslides in the core city of Zefat. The current engineering status of the city is poor, and as a consequence severe damage and loss of life are expected in future earthquakes due to EILS, unless major engineering efforts are made. Cities in the Eastern Mediterranean with comparable long habitation histories (e.g., Jerusalem, Tiberias, Nablus, Amman) are expected to have similar geotechnical problems in their old sections and are advised to take appropriate engineering steps to reduce damage and loss of life in future earthquakes.
Evaluation of historical earthquake magnitudes based on reported local-damage may, however, lead to overestimated magnitudes where the damaged sites are built on anthropogenic talus (a common setting in the vicinity of the Dead Sea Transform). 相似文献
30.