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101.
Development and assessment of damage‐to‐loss models for moment‐frame reinforced concrete buildings 下载免费PDF全文
Luís Martins Vítor Silva Mário Marques Helen Crowley Raimundo Delgado 《地震工程与结构动力学》2016,45(5):797-817
The assessment of earthquake loss often requires the definition of a relation between a measure of damage and a quantity of loss, usually achieved through the employment of a damage‐to‐loss model. These models are frequently characterized by a large variability, which inevitably increases the uncertainty in the vulnerability assessment and earthquake loss estimation. This study provides an insight on the development of damage‐to‐loss functions for moment‐frame reinforced concrete buildings through an analytical methodology. Tri‐dimensional finite element models of existing reinforced concrete buildings were subjected to a number of ground motion records compatible with the seismicity in the region of interest, through nonlinear dynamic analysis. These results were used to assess, for a number of damage states, the probability distribution of loss ratio, taking into consideration member damage and different repair techniques, as well as to derive sets of fragility functions. Then, a vulnerability model (in terms of the ratio of cost of repair to cost of replacement, conditional on the level of ground shaking intensity) was derived and compared with the vulnerability functions obtained through the combination of various damage‐to‐loss models with the set of fragility functions developed herein. In order to provide realistic estimates of economic losses due to seismic action, a comprehensive study on repair costs using current Portuguese market values was also carried out. The results of this study highlight important issues in the derivation of vulnerability functions, which are a fundamental component for an adequate seismic risk assessment. © 2015 The Authors. Earthquake Engineering & Structural Dynamics published by John Wiley & Sons Ltd. 相似文献
102.
M. J. Matias J. M. Marques P. Figueiredo M. J. Basto M. M. Abreu P. M. Carreira C. Ribeiro A. Flambó J. Feliciano E. M. Vicente 《Environmental Geology》2009,56(6):1227-1235
Santa Margarida Military Camp (S.M.M.C.) is the only one Portuguese military training area, including firing ranges for tactical
military manoeuvres of mechanised divisions. For this reason, various negative effects on the environment were expected due
to the military activities, as the Military Camp’s area is classified as a high vulnerability area to pollution of its multilayer
porous aquifers. The aim of this study was to identify and characterise local/regional geochemical impacts caused by the continuing
military training activities performed at S.M.M.C. in the course of 52 years. An overview of the geochemical research issues
as a basis for risk assessment is presented. A special attention has been put on the quality of local and regional surface
waters, shallow groundwaters and groundwaters. Local soils and sediments as well as fragments of shells and bullets were sampled
and analysed. The results so far obtained, indicated that none pollution effects were a consequence of the military training
activities. Till now, the geochemical signatures such as, high levels of K, Cl and NO3 in waters, detected in particular sites, should be faced as tracers of diffuse pollution ascribed to urban waste disposal
and cattle breading. 相似文献
103.
Patricia de Oliveira Melo Renata Marques de Britto Tharcisio Cotta Fontainha Adriana Leiras Renata Albergaria de Mello Bandeira 《Natural Hazards》2017,89(3):1343-1368
Warning systems help reduce damage and save lives in disasters; however, there is a lack of research analyzing the population perception of these systems. In Rio de Janeiro (Brazil), because the city slums face the risk of landslides caused by heavy rains, a siren early warning system named “Alerta Rio” was installed in 102 areas. The purpose of this paper was to understand the perception of community leaders regarding this alert system. To this end, a survey was conducted with community leaders to collect data on whether and why the public do or do not attend to the alert. Results indicated that (1) public adherence to Alerta Rio is low despite the generally positive view of the system, (2) local violence was reported as the reason for staying at home to protect one’s property, and (3) problems with temporary shelters and the routes to them result in lack of people’s involvement in the system. Whereas these factors are similar to population perception regarding other warning systems, the community leaders also raised the public’s lack of trust in the city hall’s adopted concept of risk and in the politicians as a relevant factor in the population perception of Alerta Rio. These factors, together with the lack of prevention policies complementary with the alert system, led to perception of reduced importance of the system. For potential solutions to enhance alarm compliance, this study recommends improvement in communication, educational programs, and public engagement strategies tailored for each target group. 相似文献
104.
Michel Michaelovitch de Mahiques Ilana Klein Coaracy Wainer Leticia Burone Renata Nagai Silvia Helena de Mello e Sousa Rubens Cesar Lopes Figueira Ilson Carlos Almeida da Silveira Mrcia Caruso Bícego Daniel Pavani Vicente Alves
yvind Hammer 《Quaternary International》2009,206(1-2):52
A high-resolution, multi-proxy record has been used to determine the environmental changes during the Holocene on the southern Brazilian shelf. Present oceanographic conditions reveal wind and freshwater input as the determinants of short-term productivity changes in the study area. Magnetic susceptibility and grain-size variations, together with proxies of productivity (organic carbon, carbon accumulation rate, Ba, Sr, and Ca content, Ba/Al, Ba/Ti, and Al/Ti ratios) were analyzed and compared with proxies of redox condition (V/Ti ratio), terrigenous input (Fe/Ca and Ti/Ca ratios), as well as other Element/Ti ratios, to evaluate the paleoceanographic and paleoclimatic changes over the period.The core covers a time interval of about 7650 years, with sedimentation rates varying from 0.025 to 0.250 cm a−1, which represent time intervals of between 8 and 80 a per sample. There is a clear change in the sedimentation rate at about 2800 B.P.All grain-size and elemental results indicate the occurrence of conspicuous changes between 5200 and 5000 cal. B.P., as well as between 3000 and 2800 cal. B.P. A comparison of the results with the palynological information available from the adjacent continental areas suggests that the sedimentary changes in this last interval may be correlated with the onset of modern climatic conditions in South America, and especially, with the onset of the Plata Plume Water, a water mass that carries cold, less saline waters towards the north. However, minor changes are observed at ca. 1500 B.P. and are correlated with an increase in the atmospheric humidity. Furthermore, a time-series analysis undertaken using several proxies indicated the occurrence of Sub-Milankovitch cycles, which may be compared with those reported worldwide. 相似文献
105.
M. Marques I. Surez-Ruiz D. Flores A. Guedes S. Rodrigues 《International Journal of Coal Geology》2009,77(3-4):377-382
In order to identify the parameters that best characterize the chemical and structural evolution of organic matter during coalification, the relationships between optical, chemical and micro-structural parameters in high-rank coals and natural graphite were studied. The samples include anthracites from Peñarroya–Belmez–Espiel Basin (Spain), Douro Basin (Portugal), and Alto Chicama Basin (Peru); and natural graphite from Canada, Mozambique, and Austria.Correlations between the following optical parameters were assessed: vitrinite random reflectance (Rr), Reflectance Indicating Surfaces (RIS) axis (RMAX, RINT and RMIN), and RIS parameters (Ram, Rev and Rst), as well as Bw and AI anisotropy parameters. Furthermore, the chemical parameters used were chosen according to their significant variation in coals, namely volatile matter, carbon, and hydrogen contents calculated in dry ash free basis (VMdaf, Cdaf, Hdaf), as well as the H/C atomic ratio. Structural organization was characterized by micro-Raman spectroscopy and XRD. Raman parameters used were the full width at half maximum (FWHM) and position of G and D1 bands on the first-order Raman spectrum, and the ID1/IG intensity area ratio. The selected XRD parameters were interlayer spacing d002, and crystallite sizes La and Lc.Results show that: (i) RMAX RIS axis seems to correlate best with chemical and micro-structural parameters; (ii) for the majority of studied samples, Hdaf and H/C atomic ratio are the only chemical parameters with significant correlations with RMAX; (iii) the FWHM of the G band of Raman spectrum shows good linear correlation with the XRD parameter d002; and, (iv) structural organization of carbon materials, as measured by trends in their optical and crystalline parameters, is influenced by their hydrogen content (daf basis) and therefore by the H/C atomic ratio. 相似文献
106.
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108.
Aesthetic characteristics are important when rocks are used as construction materials. Among all the surface finishes available, the polished finish is the one which best enhances the rock attractiveness. Colour (C), roughness (R) and gloss (G) are surface properties usually used to assess the rock polishing. In this research, the CRG properties were assessed in polished samples of three ornamental granites with different textures and physical–mechanical properties, one weathered and two sound. C was evaluated in CIE-L * a * b * and CIE-L * C * ab h ab systems, R with R a and R z parameters and G using the 20°, 60° and 85° geometries. The weathered granite presents a noticeable colour variation, especially in the b * parameter, while the sound ones have a more homogeneous colour. Sound and more textural homogeneous granites have a low surface roughness and high gloss, which are uniformly distributed. The weathered granite shows a higher surface roughness and lower gloss, with scattered distribution. The mineral contacts are the main cause of the surface irregularities. The results show the interdependence between the CRG properties and stress the importance of the polishing process for enhancing the aesthetic characteristics of the granites. CRG properties could be used for quality control in granite processing plants, thus avoiding noticeable differences in the facades of buildings, particularly when weathered granites are used. 相似文献
109.
da Silveira Lucas Cardoso de Oliveira Amauri Pereira Sánchez Maciel Piñero Codato Georgia Ferreira Maurício Jonas Filho Edson Pereira Marques Božnar Marija Zlata Mlakar Primož 《Boundary-Layer Meteorology》2022,185(2):197-197
Boundary-Layer Meteorology - 相似文献
110.
Fernando O. Marques Fernando M. S. F. Marques António Mateus Jorge Figueiras Fernando M. Santos Rogério Mota Helena Amaral 《Environmental Geology》2005,47(8):1128-1137
A sodium bentonite is being used in the basal-isolation of landfills installed on strongly fractured granitic rocks of N Portugal (NW Iberia). To evaluate the performance of this clay as the ultimate impermeable basal barrier, a detailed study was carried out of the granite fracture network; the Na-bentonite was tested to characterize its mechanical and geotechnical behavior; geophysical surveys were made to search for landfill leakage and the waters found around the landfill were geochemically characterized. Fractures in the granite are usually open and devoid of mineral infillings or clay materials and, thus, permeability of the granite is very high. Dispersal of contaminants can be further enhanced by the position of the landfill on a high steep-sided ridge. Geophysical and geochemical data show evidence for seepage and dispersion of pollutants, which means that the clay failed as an ultimate isolation barrier against seepage. This investigation shows that this can be due to fracturing of the clay under load and/or to its non-homogeneous saturation and extreme shrinking character upon drying, which are accompanied by the formation of extensive cracking. Observations and experimental results suggest that the use of synthetic clays in the safe building of landfill bottom liners needs further research, and extreme care should be taken in preventing that clay water content suffers large variations after saturation, as this process considerably degrades the mechanical behavior and sealing properties of the studied Na-bentonite. 相似文献