Development of fragility functions as a damage classification/prediction method for steel moment‐resisting frames using a wavelet‐based damage sensitive feature     

Hae Young Noh  Dimitrios G. Lignos  K. Krishnan Nair  Anne S. Kiremidjian 《地震工程与结构动力学》2012,41(4):681-696

Fragility functions are commonly used in performance‐based earthquake engineering for predicting the damage state of a structure subjected to an earthquake. This process often involves estimating the structural damage as a function of structural response, such as the story drift ratio and the peak floor absolute acceleration. In this paper, a new framework is proposed to develop fragility functions to be used as a damage classification/prediction method for steel structures based on a wavelet‐based damage sensitive feature (DSF). DSFs are often used in structural health monitoring as an indicator of the damage state of the structure, and they are easily estimated from recorded structural responses. The proposed framework for damage classification of steel structures subjected to earthquakes is demonstrated and validated with a set of numerically simulated data for a four‐story steel moment‐resisting frame designed based on current seismic provisions. It is shown that the damage state of the frame is predicted with less variance using the fragility functions derived from the wavelet‐based DSF than it is with fragility functions derived from an alternate acceleration‐based measure, the spectral acceleration at the first mode period of the structure. Therefore, the fragility functions derived from the wavelet‐based DSF can be used as a probabilistic damage classification model in the field of structural health monitoring and an alternative damage prediction model in the field of performance‐based earthquake engineering. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Development of empirical and analytical fragility functions using kernel smoothing methods          下载免费PDF全文

Hae Young Noh  David Lallemant  Anne S. Kiremidjian 《地震工程与结构动力学》2015,44(8):1163-1180

Fragility functions that define the probabilistic relationship between structural damage and ground motion intensity are an integral part of performance‐based earthquake engineering or seismic risk analysis. This paper introduces three approaches based on kernel smoothing methods for developing analytical and empirical fragility functions. A kernel assigns a weight to each data that is inversely related to the distance between the data value and the input of the fragility function of interest. The kernel smoothing methods are, therefore, non‐parametric forms of data interpolation. These methods enable the implicit treatment of uncertainty in either or both of ground motion intensity and structural damage without making any assumption about the shape of the resulting fragility functions. They are particularly beneficial for sparse, noisy, or non‐homogeneous data sets. For illustration purposes, two types of data are considered. The first is a set of numerically simulated responses for a four‐story steel moment‐resisting frame, and the second is a set of field observations collected after the 2010 Haiti earthquake. The results demonstrate that these methods can develop continuous representations of fragility functions without specifying their functional forms and treat sparse data sets more efficiently than conventional data binning and parametric curve fitting methods. Moreover, various uncertainty analyses are conducted to address the issues of over‐fitting, bias, and confidence intervals. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Detection of multiple potentially pathogenic bacteria in Matang mangrove estuaries,Malaysia     

Aziz Ghaderpour  Khairul Nazrin Mohd Nasori  Li Lee Chew  Ving Ching Chong  Kwai Lin Thong  Lay Ching Chai 《Marine pollution bulletin》2014

The deltaic estuarine system of the Matang Mangrove Forest Reserve of Malaysia is a site where several human settlements and brackish water aquaculture have been established. Here, we evaluated the level of fecal indicator bacteria (FIB) and the presence of potentially pathogenic bacteria in the surface water and sediments. Higher levels of FIB were detected at downstream sampling sites from the fishing village, indicating it as a possible source of anthropogenic pollution to the estuary. Enterococci levels in the estuarine sediments were higher than in the surface water, while total coliforms and E. coli in the estuarine sediments were not detected in all samples. Also, various types of potentially pathogenic bacteria, including Klebsiella pneumoniae, Serratia marcescens and Enterobacter cloacae were isolated. The results indicate that the Matang estuarine system is contaminated with various types of potential human bacterial pathogens which might pose a health risk to the public.  相似文献   

Role of the upper ocean structure in the response of ENSO-like SST variability to global warming     

Sang-Wook Yeh  Boris Dewitte  Bo Young Yim  Yign Noh 《Climate Dynamics》2010,35(2-3):355-369

The response of El Niño and Southern Oscillation (ENSO)-like variability to global warming varies comparatively between the two different climate system models, i.e., the Meteorological Research Institute (MRI) and Geophysical Fluid Dynamics Laboratory (GFDL) Coupled General Circulation Models (CGCMs). Here, we examine the role of the simulated upper ocean temperature structure in the different sensitivities of the simulated ENSO variability in the models based on the different level of CO₂ concentrations. In the MRI model, the sea surface temperature (SST) undergoes a rather drastic modification, namely a tendency toward a permanent El Niño-like state. This is associated with an enhanced stratification which results in greater ENSO amplitude for the MRI model. On the other hand, the ENSO simulated by GFDL model is hardly modified although the mean temperature in the near surface layer increases. In order to understand the associated mechanisms we carry out a vertical mode decomposition of the mean equatorial stratification and a simplified heat balance analysis using an intermediate tropical Pacific model tuned from the CGCM outputs. It is found that in the MRI model the increased stratification is associated with an enhancement of the zonal advective feedback and the non-linear advection. In the GFDL model, on the other hand, the thermocline variability and associated anomalous vertical advection are reduced in the eastern equatorial Pacific under global warming, which erodes the thermocline feedback and explains why the ENSO amplitude is reduced in a warmer climate in this model. It is suggested that change in stratification associated with global warming impacts the equatorial wave dynamics in a way that enhances the second baroclinic mode over the gravest one, which leads to the change in feedback processes in the CGCMs. Our results illustrate that the upper ocean vertical structure simulated in the CGCMs is a key parameter of the sensitivity of ENSO-like SST variability to global warming.  相似文献   

A review on 3D terrain visualization of GIS data: techniques and software     

Che Mat RUZINOOR  Abdul Rashid Mohamed SHARIFF  Biswajeet PRADHAN  Mahmud RODZI AHMAD  Mohd Shafry Mohd RAHIM 《地球空间信息科学学报》2012,15(2):105-115

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Chemical weathering in the Three Rivers region of Eastern Tibet   总被引：2，自引：0，他引：2  

Hyonjeong Noh  Jianhua Qin 《Geochimica et cosmochimica acta》2009,73(7):1857-7854

Three large rivers - the Chang Jiang (Yangtze), Mekong (Lancang Jiang) and Salween (Nu Jiang) - originate in eastern Tibet and run in close parallel over 300 km near the eastern Himalayan syntaxis. Seventy-four river water samples were collected mostly during the summer season from 1999 to 2004. Their major element compositions vary widely, with total dissolved solids (TDS) ranging from 31 to 3037 mg/l, reflecting the complex geologic makeup of the vast drainage basins. The major ion distribution of the main channel samples primarily reflects the weathering of carbonates. Evaporite dissolution prevails in the headwater samples of the Chang Jiang in the Tibetan Plateau interior, as evidenced by the high TDS (928 and 3037 mg/l) and the Na-Cl dominant major element composition. Local tributary samples of the Mekong and Salween, draining the Lincang Batholith and the Tengchong Volcano, show distinctive silicate weathering signatures. We used five reservoirs - rain, halite, sulfate, carbonate, and silicate - in a forward model to calculate the contribution from silicate weathering to the total dissolved load and to estimate the consumption rate of atmospheric CO₂ by silicate weathering. Carbonate weathering accounts for about 50% of the total cationic charge (TZ⁺) in the samples of the Mekong and the Salween exiting the Tibetan Plateau. In the “exit” sample of the Chang Jiang, 45% of TZ⁺ is from halite dissolution inherited from the extreme headwater tributaries in the interior of the plateau, and carbonates contribute only 26% to the TZ⁺. The net rate of CO₂ consumption by silicate weathering is (103-121) × 10³ mol km⁻² year⁻¹, lower than the rivers draining the Himalayan front. GIS-based analyses indicate that runoff and relief can explain 52% of the spread in the rate of atmospheric CO₂ drawdown by silicate weathering, but other climatic (temperature, precipitation, potential evapotranspiration) and geomorphic (elevation, slope) factors also show collinearity. Only qualitative conclusions can be drawn for the significance of lithology due to lack of digitized lithologic information. The effect of the peculiar drainage pattern due to tectonic forcing is not readily apparent in the major element composition or in increased chemical weathering rates. The ⁸⁷Sr/⁸⁶Sr ratios and the silicate weathering rates are in general lower in the Three Rivers than in the rivers draining the Himalayan front.  相似文献   

Utilization of bituminous limestone ash from EL-Lajjun area in production of lightweight Masonry block     

Nafeth A. Abdul Hadi  Hani Nicola Khoury  Mohd Suliman Kharabsheh 《Acta Geotechnica》2009,4(3):215-222

The following work aims at minimizing the environmental impact of the solid wastes (ash) that is produced after the utilization of the bituminous limestone in thermal power stations and/or retorting processes. The laboratory tests have been selected with respect to construction needs and possible post construction conditions. Utilization of the various types of ash in the production of lightweight concrete block has revealed optimum results. The compressive strength of various ash–glass sand mixes has ranged between 19 and 76 kg/cm² at 28 days. The compressive strength of ash–tuff mixes has ranged between 54 and 63 kg/cm² at 28 days. Ultra light mixtures using ash–polyester with a density of 0.88 kg/m³ and a compressive strength of 21 kg/cm² at 28 days are produced at normal room curing temperature without the use of ordinary Portland cement. The high alkalinity of El-Lajjun ash is considered a disadvantage when utilized in normal concrete mixes for structural purposes. Ash only can be mixed with aggregates to produce lean concrete for blinding purposes for use in foundations.  相似文献   

Mercury concentrations in environmental media at a hazardous solid waste landfill site and mercury emissions from the site     

Young-Ji Han  Pyung-Rae Kim  Gang-San Lee  Jae-In Lee  Seam Noh  Seok-Min Yu  Kwang-Su Park  Kwang-Seol Seok  Hyuk Kim  Young-Hee Kim 《Environmental Earth Sciences》2017,76(10):361

Mercury (Hg) concentrations in air, effluent water, landfill gas, leachate, groundwater, and soil at a hazardous solid waste landfill site in Korea were measured along with air–soil surface Hg exchange fluxes at the site. The concentrations and fluxes were considerably higher than have been found elsewhere in Korea. Gaseous Hg concentrations in the air peaked during the day, coinciding with Hg being released from the landfill surface. This suggests that air–soil exchange increased the Hg concentrations in the atmosphere. The air–soil exchange flux increased abruptly when solar radiation reached the soil surface. The Hg flux peaked about 3 h before the solar radiation peaked, possibly because reducible Hg was abundant at the soil surface. The Hg emission flux activation energy (E _a) was low, indicating that the Hg species present and Hg–soil binding were probably not as important (because of the high Hg content of the soil) as in previous studies. The methylmercury to total Hg ratios in the discharged effluent, groundwater, and leachate was clearly higher than typically found in coastal water and freshwater, suggesting bacteria caused active methylation to occur under the reducing conditions in the anaerobic landfill. The results suggested that considerable amounts of Hg are probably transported from the landfill to nearby environmental media and that this will continue if waste with a high Hg content continues to be added to the landfill without being pretreated.  相似文献   

Inversion of two-phase extensional basin systems during subduction of the Paleo-Pacific Plate in the SW Korean Peninsula:Implication for the Mesozoic “Laramide-style” orogeny along East Asian continental margin     

Seung-Ik Park  Jungrae Noh  Hee Jun Cheong  Sanghoon Kwon  Yungoo Song  Sung Won Kim  M.Santosh 《地学前缘(英文版)》2019,10(3):909-925

During subduction, continental margins experience shortening along with inversion of extensional sedimentary basins. Here we explore a tectonic scenario for the inversion of two-phase extensional basin systems, where the Early-Middle Jurassic intra-arc volcano-sedimentary Oseosan Volcanic Complex was developed on top of the Late Triassic-Early Jurassic post-collisional sequences, namely the Chungnam Basin. The basin shortening was accommodated mostly by contractional faults and related folds. In the basement, regional high-angle reverse faults as well as low-angle thrusts accommodate the overall shortening, and are compatible with those preserved in the cover. This suggests that their spatial and temporal development is strongly dependent on the initial basin geometry and inherited structures.Changes in transport direction observed along the basement-sedimentary cover interface is a characteristic structural feature, reflecting sequential kinematic evolution during basin inversion. Propagation of basement faults also enhanced shortening of the overlying sedimentary cover sequences. We constrain timing of the Late Jurassic-Early Cretaceous(ca. 158-110 Ma) inversion from altered K-feldspar 40 Ar/39 Ar ages in stacked thrust sheets and K-Ar illite ages of fault gouges, along with previously reported geochronological data from the area. This "non-magmatic phase" of the Daebo Orogeny is contemporaneous with the timing of magmatic quiescence across the Korean Peninsula. We propose the role of flat/low-angle subduction of the Paleo-Pacific Plate for the development of the "Laramide-style" basement-involved orogenic event along East Asian continental margin.  相似文献   

Interaction between Wind and Temperature Fields in the Planetary Boundary Layer for a Spatially Heterogeneous Surface Heat Flux     

Hyoung-Jin Kim  Yign Noh  Siegfried Raasch 《Boundary-Layer Meteorology》2004,111(2):225-246

Interaction between wind and temperature fields in the planetary boundary layerfor a spatially heterogeneous surface heat flux has been investigated using large-eddysimulation. It is shown that a substantial difference exists in the wind and temperaturefields, depending on whether the directions of the background wind and the surfaceheat flux variation are parallel or perpendicular.When they are parallel to each other, two-dimensional plumes induced by theheterogeneous surface heat flux are easily destroyed by the background wind,and the velocity field is strongly modified by convective eddies compared tothe case when they are perpendicular to each other. This leads to a substantialdifference in the profiles of turbulent kinetic energy and its flux.It also results in a difference between the two cases in the bulk properties of theplanetary boundary layer, such as the entrainment at the top of the planetary boundarylayer and the drag at the bottom, which have important implications for boundary-layermodelling. The difference between the two cases exists even when the background windspeed is as large as 15.0 m s^-1. Meanwhile, the contrast between two cases is weakened by the Coriolis force.  相似文献