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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Korean Society of Hazard Mitigation
Journal Basic Information
Journal DOI :
Korean Society of Hazard Mitigation
Editor in Chief :
Moo Jong Park
Volume & Issues
Volume 15, Issue 6 - Dec 2015
Volume 15, Issue 5 - Oct 2015
Volume 15, Issue 4 - Aug 2015
Volume 15, Issue 3 - Jun 2015
Volume 15, Issue 2 - Apr 2015
Volume 15, Issue 1 - Feb 2015
Selecting the target year
Investigation of Effect of Steps in Inelastic-Buckling Strength of I-Beams Subjected to Two Concentrated Loads Using Experimental Tests, Finite Element Analysis and Proposed Equations
Surla, Albert S. ; Park, Jong Sup ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 1~12
DOI : 10.9798/KOSHAM.2015.15.5.1
This paper is focused on the analysis of results obtained in the experimental tests on singly symmetric doubly stepped I-beams. Specifically, two point load tests were conducted on the beams having non-compact flange sections. The tests were conducted to investigate the inelastic buckling behavior of the stepped beams. For every specimen, the main parameters are the unbraced length and the stepped beam parameters. Four short span specimens were tested and the monosymmetric ratio of all the beams was fixed at 0.7. The unbraced lengths were 3 meters and 4 meters. Furthermore, the buckling capacity of the stepped beams were investigated by using finite element analyses. The results were also compared to equations proposed by different researchers which determine the buckling capacity of stepped beams. Also, values recommended by various codes of practice on prismatic beams were used as a reference to determine the accuracy of the finite element models. Results showed that the values yielded by FEA had a good correlation with the values obtained from the tests. Meanwhile, the equations used to determine the strengths of the stepped beams yielded over conservative and unconservative results. The significant effect of steps in increasing the capacity of the beams was also observed.
Evaluation of Drivers' Detection Distance according to the Local Lightings Condition of Crosswalk Illumination
Park, Soon-Yong ; Lee, Suk-Ki ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 13~18
DOI : 10.9798/KOSHAM.2015.15.5.13
This study analyzes evaluation of drivers' detection distance according to the local lightings condition of crosswalk illumination which can be installed with or without the continuous lightings; here, continuous lightings mean the lightings installed with a regular spacing along the roadside of two lanes and four lanes. The study facilities dummy-detection-distance as a measure of effects observed according to the varying lighting conditions; day-time, night-time with continuous lightings only, night-time with the combination of continuous lightings and crosswalk lightings, night-time without lightings at all, and night-time with crosswalk lightings only. A dummy was installed to mimic the school-age-child who are 110 cm tall about to cross the road at crosswalk. Field test was carried out at two places; one is four lanes operated roads with the continuous lightings and the other is two lanes operated roads without the continuous. The corresponding limited speeds are 70 and 60 kph, respectively. With the data of 15th percentile dummy-detection-distance for four lanes operated roads, we conclude the distance for continuous lightings only was not satisfying the Stopping Sight Distance required at 70 kph design speed. The distance was increased with the order of combination of continuous lightings and crosswalk lightings, day-time condition, and continuous lightings only. With the same data analysis for two lanes operated roads, we conclude the distance for day-time condition only satisfy the Stopping Sight Distance required at 60 kph design speed. Especially, the average, 85% tile, 50% tile, 15% tile of a no-night-time lighting (street lamps off) were determined that the subject detection distance was very shorter than Stopping Sight Distance. Therefore, this insufficient sight distance could make heighten the possibility of accident.
Nonstationary Frequency Analysis Using a Hierarchical Bayesian Model
Jo, Aejung ; Cho, Hyungon ; Kim, Gwangseob ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 19~24
DOI : 10.9798/KOSHAM.2015.15.5.19
In this study, a nonstationary frequency analysis model was developed using a hierarchical Bayesian model. The model consists of 13 parameters which are 10 scale parameters according to different time windows, 2 hyper-parameters and 1 scale hyper-parameter. The model took use of extreme rainfall data based on POT (Peaks Over Threshold) and the GP (Generialized Pareto) distribution. The model parameters were estimated using a Gibbs sampler and Metropolis-Hastings algorithm. The model was applied for Seoul site to estimate target year probable rainfall amount and the probable rainfall estimate for the target year of 2045 is about 14-17% lager than that of current estimate according to different return periods. Results demonstrated that nonstationary frequency analysis is necessary for hydraulic structure design.
Verification of Bias Corrected Simulations of Climate Models Using Entropy
Lee, Jae-Kyoung ; Kim, Young-Oh ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 25~35
DOI : 10.9798/KOSHAM.2015.15.5.25
Spatio-temporal resolutions of hydrometeorological variables simulated by General Circulation Models (GCMs) are very sparse and biases have occurred between GCM simulations and historical observations. To overcome these limitations, GCM simulations are corrected by utilizing various bias correction methods. This study has verified the improvement of GCMs simulated precipitation after applying a bias correction method using entropy as well as basic statistics. First and foremost, this study has proposed the Composite Bias Correction (CBC) method based on a simple method during the dry season and a nested bias correction method within a flood season. Bias, RMSE and annual total precipitation of the CBC method related to observations were at 0.02 mm/month, 11.10 mm/ month, and 1325.99 mm/year(observed annual total precipitation=1326.28 mm/year), respectively and the CBC method is superior to other methods. Furthermore, GCM simulated precipitation before/after applying the CBC method was verified using entropy. Although the probability density function (pdf) of GCMs simulated precipitation before the CBC method was overestimated in a low-frequency precipitation as well as being underestimated in the flood season, pdf of bias-corrected GCM simulated precipitation was similar to the observations. Bias corrected GCM simulated precipitation that had an entropy (=5.648) similar to observations (=5.643) had statistical characteristics and uncertainty analogous in comparison to observed precipitation. Therefore, the bias correction method does correct the biases of GCMs simulated variables and simulates the uncertainty of observation properly.
Assessment on the Application of Prediction of Summer Monsoon Precipitation over the Han River Basin using Global Temperature Indices
Jeong, Min-Su ; Kim, Jong-Suk ; Lee, Tae-Sam ; Moon, Young-Il ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 37~45
DOI : 10.9798/KOSHAM.2015.15.5.37
In the current study, we analyzed the characteristics of summer precipitation variability in the Han River basin using the Land-Ocean Contrast (LOC) and Meridional Temperature Gradient (MTG) temperature indices. To analyze the complex characteristics of abnormal variations internalized in the long-term temperature indices, the Ensemble Empirical Mode Decomposition (EEMD) method was applied to extract Intrinsic Mode Functions (IMFs), a finite number of variation patterns. The extended IMFs were applied to the Multi-layer Perceptron Artificial Neural Network (MLP-ANN) model to forecast the short-term period of two temperature indices. In addition, we performed grouping on summer precipitation with using decision making model, Tree model. We also, studied nontyphoons precipitation in consideration of the complex effects of the two temperature indices and examined the applicability of forecast regarding the monsoon related precipitation during the summer season over the Han River basin.
An Analysis on the Distribution Patterns of Fire Occurrence in Cheongju City Using the Spatial Statistics Method
Yeon, Gyung Hwan ; Kwon, Soon-Teak ; Hwang, Hee-Yun ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 47~57
DOI : 10.9798/KOSHAM.2015.15.5.47
This study is intended to draw up a distribution map of fire occurrence and analyze the patterns of fire occurrence by using spatial statistics method. The results of the study are as follows. First, the results of kernel density analysis have revealed that the density of fire hot spots was the highest in the downtown of Cheongju City and high in the Eup and Myeon locating in the surroundings of downtown owing to population growth related to the construction of industrial and housing complexes. Second, when the number and damage of fire occurrence were correspondence, urban periphery
have any regional correlation except for downtown. Third, when the spatial distribution patterns of fire occurrence in Cheongju City were analyzed by spatial autocorrelation,
Index was 0.334 representing positive correlation, which means that the neighboring areas, which have a similar fire occurrence frequency to fire hot spots, are forming a zone owing to distribution. Fourth, the high damage regions of fire occurrence in Cheongju City were Heungdeok-gu and Seowon-gu, western areas of the downtown of the city. Therefore, fire prevention activities need to be centered in those areas.
An Experimental Study for Drainage Capacity Improvement at Drainage Well of Waterway
Kim, Jung Soo ; Ryu, Taek Hee ; Yoon, Sei Eui ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 59~66
DOI : 10.9798/KOSHAM.2015.15.5.59
Recently, inundation damage of road was seriously occurred without drainage well or overflow due to lack of drainage capacity at drainage well installed on the slopes. The drainage well has a very important role in the rainfall drainage from the slopes. However, drainage well of waterway was installed in accordance with the site conditions during construction because the design and installation criteria of drainage well were unclear. Therefore, it is necessary to analyze flow characteristics and drainage capacity at drainage well of waterway for improvement of the design criteria. In this study, hydraulic experiment was conducted to analyze the flow characteristics and enact standard design criteria of drainage well. Hydraulic experimental apparatus(1/4 reduction model) which can change the slope of waterway and the joining heights of waterway and drain pipe were installed to analyze of flow characteristics at the drainage well. The drainage efficiency of the drainage well was increased when the waterway was connected at the 1/3h of the drainage well and the drain pipe was joined at the 0.3D of the drainage well.
Comparative Analysis of Certification in between Performance of Disaster Safety Technology and Business Continuity Management System (BCMS)
Cheung, Chong Soo ; Yoon, Dong Keun ; Kim, Tae hwan ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 67~77
DOI : 10.9798/KOSHAM.2015.15.5.67
Certification system becomes an essential factor in global market, because it could lower barriers to entry into markets providing the standardization and reliability of products and services. Certification system could help expand economic interest and territory. Certification is activated one of the ways to trade a product as intellectual property rights, and developed along with intellectual property policy. In the field of disaster management, Business Continuity Management System (BCMS, ISO 22301) was developed globally in 2012 and certification system for enterprise with outstanding performance in disaster mitigation was introduced under the Act on assistance to the autonomous activities of enterprises for disaster mitigation in Korea. Since there is no international standard for certification system in the field of disaster and safety technology, it is urgently required to study to develop standards of performance certification for disaster and safety technology for entering global markets. This study analyzes and compares domestic and international certification system including BCMS to develop the Excellent Performance Certification on Disaster and Safety Technology. Moreover, this study suggests the needs of introduction of the Excellent Performance Certification System on Disaster and Safety Technology to vitalize business market related with disaster and safety technology, to enhance international cooperation, and to increase technology transfer to overseas. Especially, standardization and legislation of certification for disaster and safety technology in Korea are urgently necessary to form the foundation of international standardization, expand economical territory, and introduce of the excellence of creative economy.
An Inventory Analysis for Disaster Loss Estimation Specialized in Korean Environment - Focusing on HAZUS-MH Flood Model -
Lee, Chang Hee ; Kim, Sang Ho ; Park, In Chan ; Kim, Byung Sik ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 79~87
DOI : 10.9798/KOSHAM.2015.15.5.79
HAZUS-MH (Hazard US Multi-Hazard) by FEMA (Federal Emergency Management Agency) in USA to estimate the damage and losses caused by the disaster helps plan the disaster prevention, preparedness, response and recovery. This study aims to present a direction of an inventory building of disaster loss estimation system inventory that can reflect Korean inventory environment by investigating the HAZUS-MH and Korean related inventory structure and analyzing the applicability to the domestic situation. In this study,
analyze the flood model in HAZUS-MH, and review the applicability and the similarity of domestic DB based on the inventory of HAZUS-MH model. It will be possible to develop a future Korean HAZUS-MH system by analysis of data linking, requirement, and necessary guidance for domestic inventory development which helps produce disaster loss estimation.
GIS-based Analysis on Characteristics of the Influential Factors Causing Landslides in Mountainous National Parks
Kwon, Hyunjung ; Woo, Choongshik ; Kim, Dongyeob ; Lee, Changwoo ; Youn, Hojoong ; Park, Sang-Jun ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 89~96
DOI : 10.9798/KOSHAM.2015.15.5.89
This study was carried out to analyze characteristics of the influential factors causing landslides in mountainous National Parks (Mt. Seorak and Mt. Jiri) and Non-National park areas (Bonghwa and Geochang). Analytical methods were extracting landslide-damaged spots from aerial images and making spatial DB of influential factors causing landslides with using GIS. Eleven factors were analyzed through spatial analysis technique and characteristics of landslide occurrence in target areas were analyzed by using likelihood ratio. Average drainage area in mountainous National Parks was two times greater than that of Non-National park areas. Also, in mountainous National Parks, slope and curvature was complex and concave. Major age class was seventh and the diameter was third or fourth. As a result of analyzing likelihood ratio to compare landslide occurrence rate in mountainous National Parks and Non-National park areas, areas with an drainage area between 2,000 to
have greater drainage area than general mountainous areas. Also, in mountainous National Parks, slope and curvature showed more concave areas, was compared start contrast to general mountainous areas showing more convex areas. Age class of fourth and seventh, and DBH of four have the highest likelihood ratio in mountainous National Parks, which was different from general mountainous areas where age class of two and three, and diameter of two and three had the highest likelihood ratio.
A Status of Landslide Damage in Mountainous National Park of Korea Using Temporal Spatial Images
Kwon, Hyunjung ; Lee, Changwoo ; Woo, Choongshik ; Kim, Dongyeob ; Youn, Hojoong ; Park, Sang-Jun ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 97~102
DOI : 10.9798/KOSHAM.2015.15.5.97
This study analyzed damages from landslides in 14 mountainous national parks with the temporal spatial data between 1986 and 2013. First, landslide disaster areas were selected through visual identification. Then a DB was made by estimating data including time of occurrence, location and scale of landslides. It showed Mt. Seorak National Park recorded the largest damage area from landslide followed by Mt. Jiri and Mt. Naejang National Parks. The year 1995 showed the highest number of cases when landslides occurred in eight National Parks. Also, the largest area damaged by landslides reached 513.7 ha in 2006 while the second largest recorded 90 ha in 1998, which were occurred in Mt. Seorak and in Mt. Jiri respectively. Compared to the result of previous field survey, total damaged area calculated by this analysis amounted to 989 ha. It was about 13 times higher than the result from field survey 73 ha. When it comes to frequency, the result from this analysis 1,600 times outnumbered field survey 142 times by approximately 11 times.
Design and Numerical Analysis on Mechanical Exhaust System in Large Space
Kim, Jung Yup ; Ahn, Chan Sol ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 103~108
DOI : 10.9798/KOSHAM.2015.15.5.103
Because of extended floor height in large space, smoke generated in fire would possibly reach to hundreds of thousands CMH and more difficulty in limiting the smoke than normal building requires effective smoke control system design and operation for a large space. In this study, design of mechanical smoke control for a large space was carried out based on existing design standard with regard to large space model and numerical analysis was also carried out using 3D numerical analysis method. Numerical analysis was carried out while changing flow rate of mechanical exhaust, which was followed by analysis of the result. As a result of implementing the design by incorporating major design factors including thickness of smoke layer, heat release rate, mass flow rate of plume, air supply velocity, maximum flow rate per exhaust outlet and minimum distance between exhaust outlets, total exhaust flow rate was calculated as 527,459 CMH when building height was 25 m and heat release rate of steady state was 5,275 kW. And the less the exhaust flow rate, the lower the smoke layer height and higher the smoke layer temperature.
A Study on Mechanism of Fire Spread between Rooms
Shin, Yichul ; Park, Gyewon ; Yoo, Yongho ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 109~116
DOI : 10.9798/KOSHAM.2015.15.5.109
This research study uses the multiple compartment model to conduct experiments with the objective of explaining the horizontal fire spreading behavior caused by fire plume behavior ejected from an opening that spreads from the fire compartment to an adjacent compartment in the spatial conditions where there are multiple fire plumes in the fire compartment. Through the experiment the temperature distribution inside the fire compartment and adjacent compartment according to the fire plume conditions were determined. Also a model for calculating the radiation heat that was received by the combustible material in the adjacent compartment was modeled, and by comparing the calculated values and the experiment values, the validity of the radiation heat calculation model was examined. Also using McCaffrey estimation, a simple prediction formula to calculate the adjacent compartment temperature up to point before the fire spread was proposed, and a similar trend was deduced as a result of comparing this estimation with the experiment values.
An Experimental Analysis of Thatched-Roof Materials to Assess Fire Risk in Historical Villages
Kim, Dong-Hyun ; Lee, Ji-Hee ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 117~122
DOI : 10.9798/KOSHAM.2015.15.5.117
Hahoe Village and Yangdong Village in Korea have straw-roofed houses and Shirakawa-go in Japan has silver grass-roofed houses. Combustion characteristics of these roof materials need to be identified in order to enhance fire safety in historical villages. This study used cone calorimeter (ISO 5660-1) and Flammability tester to measure combustion characteristics of thatched-roof materials to analysis hazard assessment in two historical villages. It also analyzed Time to Ignition (TTI), Effective Heat of Combustion (EHC), Heat Release Rate (HRR), Total Heat Release (THR), Mass Loss Rate (MLR) and ignition temperature. Database on combustion characteristics of straw (Oryza sativa) and silver grass (Miscanthus sinensis var. purpurascens) will be used to predict fire property of buildings and structures in historical villages. From the result, combustion data shown that Miscanthus sinensis var. purpurascens has high value than Oryza sativa for fire danger. Straw-roofed houses can be spread where is located within radius 5.68 m from straw-roofed house fires.
A Study on Analysis of Heat Release Rate on Household Goods (Computer·Desk·Electric Pad) for Fire Identification -Room Corner Test-
Park, Youngju ; Lee, Haepyeong ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 123~129
DOI : 10.9798/KOSHAM.2015.15.5.123
In this study, a combustion experiment of the monitor, body, desk, chair and electric blanket used in daily life was carried out using the oxygen consumption rate principle-based Room Corner Tester(RCT), in order to provide practical data about heat release rates and smoke release rates of daily supplies. As the result, the computer monitor's maximum heat release rate was
. This is the relatively highest heat release rate among the five daily supplies and 20.55 times bigger than the body. This was followed by the chair, electric blanket, desk and computer body. The computer monitor showed the highest total heat release rate at
and the total smoke release of the desk, electric blanket, computer body, monitor and chair was
respectively. Therefore, it is considered that heat transfer in the monitor and electric blanket with high heat release rates is fast due to the high heat quantity in the event of fire and the desk can be an important clue to measure the direction and intensity of flames, because this leaves many traces of soot caused by much smoke.
A Study on the Improvement of Fire Safety in Fire Vulnerable Districts - Focused on Seoul City -
Park, Jae Sung ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 131~137
DOI : 10.9798/KOSHAM.2015.15.5.131
The fires in the fire vulnerable districts are different from the types of fires that are observed in normal buildings and more likely to spread over to neighboring buildings, or collapse of the buildings in it, resulting in aggravating injuries or other damages. The Fire services act designates these areas as fire alert districts, while the building act classify them as the fire protection districts to perform their fire safety management functions. In this study, the statistics of fire in fire vulnerable districts and relevant provisions of the law were analyzed to identify problems in terms of fire production. Also, a survey with the fire fighters was conducted to analyze the vulnerabilities and issues in need of improvement in order to ensure material fire protection. As a result, it turned out that the application of the fire fighting facilities and the safety training of the relevant personnel had certain limitations. Therefore, it would only be possible to enhance the level of fire protection through installation fire proof construction, firewalls, or other facilities that could be used as code for a fire protection districts.
Transfer Length of 2,400 MPa PS Strand in 15 m-long Full-Scale Pretensioned Prestressed Concrete Beam
Yang, Jun Mo ; Yim, Hong Jae ; Kim, Jin Kook ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 139~146
DOI : 10.9798/KOSHAM.2015.15.5.139
In this study, 14.8 m long full scale pretensioned prestressed beam using 2,400 MPa PS strand was fabricated and the transfer length of the strand was investigated by measuring strains on nearby reinforcement steel bars. The test results of the beam were compared with small size specimen tests with a strand from previous researches (Oh and Kim, 2000; Yim et al., 2015). The full scale test showed smaller transfer length and smaller difference in the transfer lengths between at cut (sudden release by flame cut) and dead ends than small specimens with a strand. Evaluation on the equation of transfer length proposed by Oh et al. (2014), based on test and analysis results of transfer length of 1,860 MPa strand considering concrete compressive strength and concrete cover depth, was used to calculate the transfer length of 2,400 MPa PS strand in full scale beam as well as small specimens with a strand. Comparison of the evaluation and test results presented that the equation overestimates the transfer length of 5~9% in small specimen tests, however, more than 30% in full scale beam specimen for 2,400 MPa PS strand.
Porosity Profiles in Alluvium Soil by Using Electrical Resistivity and Geostatistic Method
Min, Dae Hong ; Yoon, Hyung Koo ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 147~154
DOI : 10.9798/KOSHAM.2015.15.5.147
The geostatistical method has been applied to predict the properties of area which has the limitation of survey. The objective of this study is to suggest the profiles of porosity based on the electrical resistivity in alluvium soil through the geostatistical method and the consideration, when applied the geostatistical method, is also suggested. An area of alluvium is chosen the site for applying the geostatistical method because an area has limitation in applying the geophysical method. In particular, the application of electrical resistivity survey is difficult because the current flow is limited into the dried and alluvium soils. The three profiles are adopted to obtain the electrical properties and the Archie's law is applied to convert the measured electrical resistivity to porosity. The Standard Penetration Test (SPT) is also performed to verify the reliability of estimated porosity and the result show the similar trend. And the effect of various statistical functions is also investigated and the slightly different distribution is observed.
Study on Physical Vulnerability Curves of Buildings by Numerical Simulation of Debris Flow
Kang, Hyo-Sub ; Kim, Yun-Tae ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 155~167
DOI : 10.9798/KOSHAM.2015.15.5.155
Residential areas and buildings located in vulnerable areas of landslide are commonly subjected to debris flow hazards. Recently, there is an increasing interest in researches on risk assessment. For a risk assessment, vulnerability assessment for the elements at risk in debris flow is required. Vulnerability assessment of elements at risk is a key component for risk assessment. Vulnerability assessment requires an understanding of the interaction between the hazard and the exposed element. This interaction can be expressed as a vulnerability curve. In this study, back analysis performed from total 4 cases of debris flow disasters occurred in between July and August, 2011. The appropriate input parameters were determined through the quantitative index analysis and survey data of debris flow affected areas. Numerical analyses were also carried out for each of the study area, Disaster-induced factors(debris flow height, velocity and impact pressure) were calculated on the damage of building. Physical vulnerability functions of masonry buildings were obtained from the relationship of the degree of building damage and the physical characteristics of debris flow obtained through the numerical analysis. The proposed physical vulnerability functions could be used as a quantitative assessment of the structural resistance of building affected by a debris flow event, and a vulnerability assessment for urban debris flow.
A Study of the Site Amplification Characteristics and Seismic Wave Energy Levels at the Sites Near the Electric Substations
Kim, Jun Kyoung ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 169~178
DOI : 10.9798/KOSHAM.2015.15.5.169
Since the domestic design response spectrum does not reflect local soil characteristics, site specific response spectrum from the observed ground motions appears relatively higher than design response spectrum at high frequency range. These problems have been pointed out frequently from the domestic seismic design industry. Among various methods, this study applied the method H/V spectral ratio of ground motion for estimating site amplification. This method recently has been extended to S waves, Coda waves, and background noise for estimating site amplification. The method of H/V spectral ratio was applied to 36 accelerations of 3 macro earthquakes (Odaesan, Jeju and Gongju earthquakes), larger than magnitude 3.4. observed simultaneously near 4 electric substation sites. Site amplifications at 4 sites, using S wave, Coda wave energy, and background noise were compared each other. The results suggested that all the electric substation sites showed similar site amplification patterns among S wave, Coda wave, and background noise. Each station showed its own characteristics of site amplification property in low, high and specific resonance frequency ranges. Comparison of this study to other results using different method can give us much more information about dynamic amplification of domestic sites characteristics and site classification.
Seismic Response of Bucket Foundations for Offshore Wind Tower
Olalo, Leonardo T. ; Choo, Yun Wook ; Yang, Sang Guk ; Seo, Ji-Hoon ; Bae, Kyung-Tae ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 179~189
DOI : 10.9798/KOSHAM.2015.15.5.179
This study aims to investigate seismic response of bucket foundations for the support of offshore wind tower. The prototype design of the bucket foundation was scaled down with a scaling number of 1/240 to manufacture the model. An additional gravity base foundation (GBF) model was prepared and its diameter is same with the bucket. The dynamic centrifuge tests for both models installed in sandy soil were carried out at 60 G resulting in the 1/4 scale prototype. Two real earthquake motions, Kobe and El Centro earthquakes were applied to the models. The earthquake motion scaled with peak accelerations from 0.02 G to 0.2 G was excited at the base of the soil container. The acceleration at the platform level (i.e. the connection of the tower and foundation) for the bucket foundation is lower than that of the GBF. The types of earthquake affected the responses at the platform. The displacement at the platform level of the bucket was also lower than the GBF. The contact pressure was at the bottom invert of both models and skirt surface of the bucket. The contact pressure at the bottom invert of the GBF significantly increases with increasing excitation while that of the bucket is negligible. The contact pressure at the skirt surface of the bucket significantly increases due to seismic loading.
Mixture Distribution Fitting and Modeling for Regional Frequency Analysis of Maximum Wind Speed Over South Korea
Ghazijahani, Nima ; Lee, Taesam ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 191~199
DOI : 10.9798/KOSHAM.2015.15.5.191
In this study, we tried to determine and investigate meteorologically homogeneous regions and to derive regional wind frequency estimates for 68 gauged sites in South Korea using an index wind method with L-moments and harmony search parameter estimation. Comparative regional wind frequency estimates were made for the tested region using various distributions, namely the Generalized Logistic (GLOG), General Extreme Value (GEV), Generalized Pareto (GPAR), Weibull. Furthermore, we applied three types of two-component mixture distributions, built by combination of Gumbel and Gamma distributions with five-parameters such as Gumbel-Gumbel (GumGum), Gamma-Gamma (GamGam), and Gamma-Gumbel (GamGum) distribution models. Their parameters are estimated by harmony search method (HS). The results of the current study showed that the Weibull distribution is identified as the bestfit distribution in Korea. In other words, Weibull as a suitable distribution with three parameters for other Korean stations.
Method for Establishing a Flood Management of Urban Watershed With Underground Sluiceway
Ahn, Jeonghwan ; Kwon, Yongchan ; Heo, Jun-Haeng ; Jeong, Changsam ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 201~208
DOI : 10.9798/KOSHAM.2015.15.5.201
A conventional concept of the flood management in urban watersheds are forced to be modified/changed since the magnitude and frequency of the urban flood have been increased due to climate change and land use change. This study proposed a method to establish a flood management in an urban watershed with pump station and underground sluiceway. The proposed method calculate the design magnitude using an urban inundation model(XP-SWMM 2011), rainfall matrix, and flood characteristic values. The calibration of the model were conducted as regulating the energy loss coefficient of bended conduits and comparing with inundation depth observed on September 21, 2010. As a result of preliminary simulation, the underground sluiceway was effective to decrease inundation, however a peak discharge of pump station was increased. Case studies were carried out in Ogeum and Moc-dong pump station basin with 5 scenarios which were composed of combination of sluiceway conditions and pump station operation rules. As the results, this study proposed the principal parameters which have to be considered for flood management and reasonable operation rules of pump station in an urban watershed with under ground sluiceway.
Risk Assessment and Mitigation Plan on Strong Wind Damages of Building Exterior Materials Induced by Open or Closed Entrance
Lee, Donghyeon ; Lim, Hyeongmin ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 209~214
DOI : 10.9798/KOSHAM.2015.15.5.209
Damages of cladding and components of buildings have been frequently occurred by both local and typhoon-induced strong winds. Their adverse effects are often increased by subsequent wind borne debris which can cause additional damage to livelihood of society. In order to mitigate the related risk, there have recently been many efforts to reduce the wind pressure on the cladding and components of buildin structures. In this study, the wind pressure on the wall of a building was calculated by computational fluid dynamics to evaluate the effects of mesh-typed openings. The results show that closed envelope of the buldiing exterior is the least vulnerable; however, employing mesh-type opening can reasonably reduce the extreme wind pressure on the wall.
Comparative Studies of MCDM for Vulnerability Analysis in Gamcheon Basin
Kim, Tae Hyung ; Kim, Byung Hyun ; Han, Kun Yeun ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 215~227
DOI : 10.9798/KOSHAM.2015.15.5.215
MCDM, which has been used in many different fields including decision making problem, is being introduced in various ways according to the basic assumption and analysis procedure. Especially in the water resources field, it is used as a raking method in various ways to quantitatively evaluate flood vulnerability of a subbasin and an administrative district. This study measured flood vulnerability of the Gamcheon basin by using Weighted Average, PROMTETHEE, Compromise Programming, VIKOR, and TOPSIS technique in order to examine the capability of various MCDM techniques which can be applied for estimating flood vulnerability of regional units. Based on the Weighted Average which is generally applied for estimating flood vulnerability, this study analyzed the correlation of vulnerability raking between different techniques to examine the technique applicability. Ultimately, it was found that the MCDM technique applications for analyzing vulnerability have applicability on most techniques.
Evaluation of Potential Flood Damage with Basin Characteristics Using Analytical Hierachy Process
Kim, Indong ; Ahn, Wonsik ; Ahn, Jaehyun ; Lee, Chaeyoung ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 229~238
DOI : 10.9798/KOSHAM.2015.15.5.229
Potential flood damage (PFD) assessment should consider the weighting and items properly depending on the characteristics of the region where each basin belongs to. However, the characteristics of the region are not considered carefully due to the pre-set determination process. It means that the applications do not reflect the field. For example, external hydropower or the uninstalled storm sewer percent of an urbanized region is not considered. Therefore, this study was performed to standardize the result of a survey of an expert group including the characteristics of the region by using analytic hierarchy process (AHP) and to suggest more accurate PFD process by applying the standardized results to PFD items assessment.
Numerical Study on Rip Current Likelihood according to the Beach Nourishment in the Haeundae Coast
Choi, Junwoo ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 239~246
DOI : 10.9798/KOSHAM.2015.15.5.239
The rip current, from which the beach-guards rescue more than 100 people every summer at Haeundae beach, is now a notorious phenomenon to cause summer safety accident. Recently the topography of Haeundae coast and beach has been changed by the beach nourishment project. The topographical change due to the beach nourishments affects the likelihood of rip current since the characteristics of rip current are varied according to the environmental sea conditions and the topography. To investigate the change of rip current likelihood varied according to the topographical change, numerical simulations utilizing the topography surveyed for the project are performed by using Boussinesq model, FUNWAVE. As a result, the liklihood of rip current at Haeundae coast slightly decreased after the beach nourishment. This might be because the width of surfzone decreased as the slope of beach profile increased.
The Sensitivity and Uncertainty Analysis of SWMM Water Quality Parameters
Chung, Gunhui ; Yeon, Jong Sang ; Sim, Kyu Bum ; Kim, Eung Seok ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 247~253
DOI : 10.9798/KOSHAM.2015.15.5.247
Due to the rapid industrialization and urbanization, many studies on nonpoint source load reduction by SWMM. In this study, Sensitivity and uncertainty analysis for the SWMM Water Quality parameters, Max.Buildup, Rate Constant, EMC Coefficient and Cleaning Efficient, were conducted. Exponential and EMC functions were selected in the Buildup and Washoff function, respectively. As a results of sensitivity analysis, Rate Constant has the highest sensitivity and Max.Buildup, Cleaning Efficient and EMC Coefficient in the order. Rate Constant has the highest uncertainty as well. Max.buildup uncertainty index depended on simulation time and simulation time in accordance with time of concentration was more carefully determined in urban area than in forest and agricultural area. This result will be able to take advantage of sewer design in urban area.
Evaluation of the WRF Model In Reproducing the Spatio-temporal Pattern of a Heavy Rainfall Event
Lee, Jeonghoon ; Jang, Suhyung ; Kim, Sangdan ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 255~265
DOI : 10.9798/KOSHAM.2015.15.5.255
This paper presented a base study for new methodology that uses a physical based regional climate model that can also incorporate the effect of the nonstationarity of atmospheric process. To this end, we examined the capability of the WRF in reproducing the selected historical heavy rainfall events over Korea. WRF used the NCEP FNL reanalysis data, RTG Sea Surface Temperature data and ADP Global Surface Observational Weather data for its initial and boundary conditions. Nine experiments are carried out by changing the physics option (microphysics processes and cumulus parameterization process). Numerical simulation results showed a big variation in rainfall according to initial and boundary condition and cumulus parameterization. In physics option, WRF single-Moment 6-class scheme and New Kain-Fritsch scheme were reasonably reproduced in spatial distribution of rainfall, but the amount was overestimated and dose not reproduce temporal distribution of rainfall. This indicates that a new methodology necessary to WRF for hazard mitigation.
Bio-Retentions Design Practice for Suspended Solids Management at Industrial Areas
Choe, Bogyeong ; Lee, Jeonghoon ; Sim, Hyunjun ; Lee, Jinhee ; Cho, Kyunghwa ; Kim, Sangdan ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 267~273
DOI : 10.9798/KOSHAM.2015.15.5.267
In this study, a design method of a bio-retention pond for reducing suspended solids at an industrial area is proposed. After simulating suspended solid loads at a study drainage catchment using SWMM calibrated with the unit load estimation method which is recently suggested by the National Institute of Environmental Research, the non-point pollutant reduction efficiency with respect to the bioretention capacity is quantified. Based on various simulation results, the stormwater captured ratio curve and the average annual fraction of suspended solid loads controlled by a bio-retention pond are derived. Using the regression analysis, coefficients of the formula for the average annual captured fraction of suspended solid loads, which is missing in the Korean TMDL technical guide, is proposed.
Application of CE-QUAL-W2 Model and Scenario Analysis for Predicting Water Quality Constituents in Sayeun Reservoir
Pyo, JongCheol ; Lee, Sanghyeon ; Kim, MinJeong ; Cho, Kyung Hwa ; Cho, Hong Je ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 275~282
DOI : 10.9798/KOSHAM.2015.15.5.275
This study estimated water quality constituents especially in CBOD, TN, TP, and Chlorophyll-a in Sayeun reservoir by using CE-QUAL-W2 model. With water quality data in surface, middle, and bottom of water body, the model calibration was implemented by changing water quality parameters in the model. Using the calibrated model, we performed scenario analysis to investigate the variation of water quality in respond to different elevations. CBOD, TN, and Chlorophyll-a concentration predicted by the model showed a good agreement with the measured the trend of the concentrations. However, TP estimated was relatively low tendency by the model. We found that water quality (i.e., CBOD, TN, TP, and chlorophyll-a) at both water surface and middle layer was degraded in respond to the decrease of water level by 6.8m. Although results of CBOD in both surface and middle layers decreased to about 2% and 1%, respectively, in the surface layer, TN, TP, and Chlorophyll-a increased to about 4%, 3%, and 51% and, in the middle, TN and TP increased up to 12% and 3%, respectively. In the middle layer, especially, water quality degraded mainly due to increased organic matter from growth, mortality, decay, and sedimentation of algae and anaerobic release of nutrients from sediment. This study demonstrated that water quality could be influenced by controlling water surface elevation, implying that there is a need to control nutrient inflow and re-suspension from sediment in the reservoir.
Urban Mud and Debris Flow Disaster Vulnerability Assessment Associated with Landslide Hazard Map: Application to Busan, Korea
Park, Yoonkyung ; Kim, Jeongsook ; Jo, Deok Jun ; Kim, Sangdan ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 283~289
DOI : 10.9798/KOSHAM.2015.15.5.283
In this study, an urban mud and debris flow disaster vulnerability assessment model based on landslide risk map being used by Korea forest service is proposed. In order to examine the vulnerability of urban areas, the assessment model is configured to reflect the exposure intensity, sensitivity level, and the ability to adapt to landslides. The proposed model consists of one zoning and three detailed indicators which are a buffer zone derived by landslide hazard map, an indicator of personal injury, an indicator to cause secondary damage, and an indicator of disaster preparedness and response capability. Three detailed indicators have six, five, and six agencyrelated variables, respectively. The weights among detailed indicators and those among surrogates that make up each detailed indicator are setting by the AHP survey technique. The developed model is applied to Busan, and the vulnerability of urban mud and debris flow disaster is evaluated.
A Study on the Application and Effect Analysis Monitoring of LID Technique in New Town City (I) LID Technique Selection and Optimum Size Estimate
Lee, Jungmin ; Lee, Yunsang ; Choi, Jongsoo ; Kang, Shinuk ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 291~299
DOI : 10.9798/KOSHAM.2015.15.5.291
With an increase in the impermeable areas being used for the construction of new town cities and urbanization, evapotranspiration and infiltration have decreased, while surface flow and non-point pollution loads have increased. As a solution to the adverse effects of development resulting from rapid urbanization, Low Impact Development(LID) techniques are being applied recently. In this study, the most suitable LID techniques were selected and an optimum area for their application was estimated in a new town city basin. The techniques such as the Infiltration Trench, Bio-retention, Tree box Filter, Artificial Wetland, and Porous Pavement were selected after reviewing the rainfall runoff management, LID techniques ability is to eliminate pollutants, and the condition of the soil in the study area. The optimum size was calculated using formulas(WQV, WQF) from various techniques, and the total LID area was calculated to be
. The methodologies used in this study for selecting the optimum LID techniques and calculating the optimum size are expected to present effective solutions in response to the recent natural disasters and climate changes, and contribute toward establishing future land use and rainfall management plans.
A Study on the Application and Effect Analysis Monitoring of LID Technique in New Town City (II) LID Practice facilities Effect Analysis Monitoring
Lee, Jungmin ; Lee, Yunsang ; Kim, Youngchul ; Kim, Leehyung ;
Journal of Korean Society of Hazard Mitigation, volume 15, issue 5, 2015, Pages 301~310
DOI : 10.9798/KOSHAM.2015.15.5.301
To prevent indiscriminate urbanization, Low Impact Development(LID) practices are being followed. LID is a management technique that enables processes such as, rainwater infiltration, retention, and evaporation to occur as they did in the natural state before development as far as possible. In this study, a test bed was constructed at each individual LID facility built at the study area for monitoring outflow and non-point pollution reduction effect analysis. The monitoring results showed the removal efficiency to eliminate pollutants such as nutrition to be good. In terms of TSS, a high removal efficiency of 57~100% was observed. Furthermore, the amount of annual retention of rainfall at each LID facility was analyzed, showing the accumulated rainfall to be in the range of around 220~580 mm per year. The results obtained from the monitoring and reduction effect analyses conducted at the LID facilities can be utilized as the basis for establishing a future plan for efficient land use and rainfall management in response to the recent natural disasters and climate changes.