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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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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 12, Issue 6 - Dec 2012
Volume 12, Issue 5 - Oct 2012
Volume 12, Issue 4 - Aug 2012
Volume 12, Issue 3 - Jun 2012
Volume 12, Issue 2 - Apr 2012
Volume 12, Issue 1 - Feb 2012
Selecting the target year
A Study on Strength of Shear Stud in High Strength Concrete
Ahn, Namshik ; Lee, Young Hak ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 1~7
DOI : 10.9798/KOSHAM.2012.12.2.001
For design of composite concrete members, the behavior between two materials; concrete and steel is considered significantly. And shear studs are generally used for effective composite action. The purpose of this paper are to propose an equation of strength of shear stud embedded in high strength concrete, and to evaluate the validity by comparing with the current design codes and existing proposed equations. The equation was proposed by regression analysis based on the test results of steel pipe encased composite members manufactured by considering diameter of shear stud and ratio of diameter to height of shear stud as variables. The comparisons of the test results with the design codes and existing proposed equations showed that KBC2009 and the equation of Cheong et al. have big error; 48.78% and 28.03%. And the equation proposed in this paper indicate relatively smaller error of 3.69%. It indicated that the proposed equation has higher accuracy for calculating the strength of shear stud embedded in high strength concrete.
Design of End Plate Stiffeners and Curved Connection of Buried Corrugated Pipes for Stress Reduction
Han, Taek Hee ; Oh, Myoung Hak ; Kang, Young Jong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 9~15
DOI : 10.9798/KOSHAM.2012.12.2.009
Safety analyses were performed for the end sides and connections of buried corrugated steel pipes. A steel end plate with stiffeners and concrete end plate were analyzed with a FEA program and their safeties were checked. The analysis results showed that the steel end plates required stiffeners for the safety. And it was efficient to increase the number of the stiffener for the safety. However, the concrete end plate was safe without any stiffener because it is very thicker than the steel one. For connection, two cases were considered. One was the connection between two pipes which had different diameters. The other case was the connection between two pipes which had equal diameters. In the first case, the stress concentration occurred along the side line of the connection. In the second case, the stress concentration occurred on the top of the connection. To mitigate the stress concentration, the connection part was redesigned to have curved surface, and it was efficient to decrease the stress concentration.
An Analysis of Fall Accidents into the Sea by the Fault Tree Analysis Method
Lim, Nam Hyoung ; Bae, Hyun Ung ; Sung, Ik Hyun ; Yi, Gyu Sei ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 17~23
DOI : 10.9798/KOSHAM.2012.12.2.017
Recently, because the waterfront development of various form have been done in the coastal zone, human's sphere of activity is approaching gradually to the sea. As a result, the riskiness of the safety accidents is increasing gradually. In addition, the frequency of the abnormal wave such as a heaving wave which is the major cause of the safety accident in the coastal zone is increasing. According to the case analysis of the accident, fall accidents into the sea at the breakwater and the rocks on the seashore is main safety accident. In this paper, in order to provide a basic information about the prevention and the countermeasure for the fall accidents into the sea, the fault tree is developed through the case analysis of the fall accidents. To investigate the frequency of the basic event in the fault tree, the survey against ordinary people and policeman is conducted. In the end, the fault tree analysis(FTA) is carried out to evaluate the risk of the fall accidents into the sea.
The Evaluation for Leakage Rate of Reactor Coolant Pump Bolting in Nuclear Power Plants
Cho, Nam Jin ; Im, Seok Been ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 25~30
DOI : 10.9798/KOSHAM.2012.12.2.025
In nuclear power plant, defected bolts used in the main flange of reactor coolant pump could have bad effect on the safety of the plant. Thus, the bolts should maintain their integrity while used in the plant. However, damaged bolts, such as corroded or cracked bolts, have been reported; thus, well-organized monitoring is required. This study evaluates safety of bolts currently used in a nuclear plant using the leakage rate. Using ANSYS program, the opening of a pump due to damaged bolts is estimated and corresponding leakage rate was estimated by SQUIRT code. The results exhibit that even in the case of 3 damaged bolts the leakage rate satisfies the allowable level, 1 gpm. However, continuous in-service inspection is still required to ensure the safety of bolts as considering the development of leakage rate.
Developing Techniques for Increasing Seismic Performance of Existing Electronic Panel on Access Floor
Choi, Eunsoo ; Kim, Jinho ; Yoo, Wan-Dong ; Lee, Seung-Yong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 31~39
DOI : 10.9798/KOSHAM.2012.12.2.031
In this study, seismic reinforced access floor system are developed and estimated through the static load test for increasing seismic performance of electronic panels which are essential to the operation of various basic facilities such as electric power, signal and communication etc. A numerical method can be used for estimating seismic performance, but shaking table test is performed because it is very difficult to mimesis access floor system, fixed condition and members of electronic panel and etc. during earthquake at near real. As a result of this study, it secured horizontal safety, one of the problems, and seismic reinforced system have secured seismic performance of electronic panel such as preventing destroy. Thus, in case of applying seismic reinforced access floor system, damaged to the electric control panel by earthquake can be effectively prevent, so that it can be greatly contributed to the stable operation of domestic basic facilities without movement and power interruption of the electric panel.
Estimating Longitudinal Elastic Wave Velocity of Bonded PSC Tendon
Kim, Byeong Hwa ; Kim, Soo Jin ; Lee, Do Hyung ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 41~45
DOI : 10.9798/KOSHAM.2012.12.2.041
This study proposes a most effective way to estimate longitudinal elastic wave velocity of bonded PSC tendon. Various longitudinal vibration tests are conducted for bonded prestressed concrete beams with different applied prestress levels. To estimate elastic wave velocity from measured structural responses, the various estimation techniques are examined such as utilization of acceleration time history, velocity time history, reflected acceleration time history, measured frequency, etc. The comparison results show that the utilization of filtered acceleration is most effective way in practice to estimate elastic wave velocity in an impact-echo test.
Numerical Verification on the Structural-health Evaluation of Subway Stations based on Statistical Pattern Recognition Technique
Shin, Jeong-Ryol ; An, Tae-Ki ; Kim, Jin-Ho ; Lee, Changgil ; Nam, Min-Jun ; Park, Seunghee ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 47~53
DOI : 10.9798/KOSHAM.2012.12.2.047
Subway is a representative public transportation that safety, above all, must be ensured. Therefore, subway stations need to be promptly maintained through the early detecting of damage conditions to guarantee the structural health and passengers' safety. However, it could be easily damaged by internal or external loads such as ambient train vibrations and even earthquake loads. For this reason, in this paper, authors suggest the structural-health evaluating algorithm based on the statistical pattern recognition techniques such as supervised and unsupervised learning method. And, also the numerical studies of Chungmuro station was carried out to verify the applicability of it into the structural-health evaluation of station structures.
Quantitative Resilience Analysis of Fiji to Cyclones
Yu, Soonyoung ; Kim, Sung Wook ; Park, Kyung-Ho ; Oh, Chang Whan ; Park, Dug Keun ; Kim, Chang Yong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 55~63
DOI : 10.9798/KOSHAM.2012.12.2.055
Resilience Cost is applied to quantitatively assess the resilience and the vulnerability of Fiji to tropical cyclones (TCs), based on historical damage data. The resilience cost, which was developed by the US Department of Homeland Security to protect critical infrastructures, is the sum of the system impact and the total recovery effort. The higher resilience cost indicates that the system is less resilient. Study results show that the resilience of Fiji to TCs depends on the strength and the path of a TC as well as inventory in affected areas. In particular, the northern division whose economy is based on commercial agriculture of sugar cane is vulnerable to TCs due to the frequency of TCs as well as the vulnerability of agriculture to TCs. This study result demonstrates that the resilience cost is a good indicator to determine a location to give priority to for resilience enhancement or recovery resources and can be used to assess causes of vulnerability. In addition, the resilience cost may be used to determine optimal recovery strategies if integrated with a modeling, simulation, and analysis program given scenario analysis capabilities.
Numerical Analysis for Optimization Method of Support Stiffness in Railway Transition Zone
Cho, In-Kyu ; Jung, Jae-Hyung ; Cho, Kook-Hwan ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 65~70
DOI : 10.9798/KOSHAM.2012.12.2.065
The structure transition zone means the stiffness varied area of substructure which holds up bridge-earthwork, earthwork-tunnel, and ballasted or concrete track. In the structure transition zone with stiffness changes, a sudden ununiform settlement is occurred by stiffness difference. Unusual vibrations and impact loadings break out in train in this zone. Therefore, recently, on the point of view of stability and maintenance of track for high-speed railway system, the transition zone should be treated with careful. In this study, the approach blocks to reduce the difference between the stiffness of the support for the plan were investigated. The research results show that the stiffness of transition zone, such as Lightweight formed concrete is considered to be the most appropriate.
Load Transfer Characteristics of a Pile installed in Clay
Lee, Seung Hyun ; Kwon, Oh Soon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 71~77
DOI : 10.9798/KOSHAM.2012.12.2.071
In order to investigate axial load transfer characteristics of a steel pipe pile installed in clay, three kinds of load transfer curves were used for analysis and results of analysis were compared each other. Two kinds of clay were considered for analysis and one of which has constant distribution of elastic modulus and undrained shear strength with depth and the other has linear distribution of those with depth. t-z curves obtained from the analysis show that pile displacements needed to develop maximum skin load transfer are less than the generally known displacement of 5~10 mm. It can be seen from the results of analysis that the amount of load transferred to pile point was small whereas the load transferred to pile point has major effect on the development of ultimate pile load capacity. Initial stiffness of load carrying capacity of a pile was mainly affected by the soil properties near the upper portion of a pile.
Suggestion of Cover-Management Factor Equation for Mountain Area in RUSLE
Lee, Jong Seol ; Won, Jin Young ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 79~85
DOI : 10.9798/KOSHAM.2012.12.2.079
RUSLE has been widely used for prediction of soil erosion in Korea. As the factors of RUSLE were suggested using observed data in agricultural land of middle-western of United State, verification is essential to apply to domestic mountain area. Cover management factor(C) is one of the most variable factors in time and space. The studies on correlation between NDVI and C factor are in progress abroad. In this study, the relationship equation between percent vegetation cover and C factor was formulated for domestic application, and was calibrated using measured data from experimental watershed. In this research, the relationship equation between percent vegetation cover and NDVI is derived using NDVI extracted from SPOT-5 image and field vegetation data. The equation proposed in this research was more suitable than Drake equation(1997). Also, for suggestion of appropriate relationship between NDVI and C factor, Knijff equation(1999) was selected, and the coefficients of this equation were suggested through the correlation analysis with measured soil erosion data.
Behavior Evaluation of Monopile Foundation Subjected to Impact Lateral Loads
Byun, Yong-Hoon ; Park, Kiwon ; Choi, Changho ; Lee, Jong-Sub ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 87~93
DOI : 10.9798/KOSHAM.2012.12.2.087
Lateral loads, including wind, ocean wave and tide affect on the stability of the monopile in the offshore wind farm. The goal of this study is to characterize the behavior of the monopile under impact lateral loading by using strain gauges. A laboratory-scale monopile system, which consists of a monopile and a support plate, is fixed into the support plate for modelling the monopile embeded in rock mass. The length of the monopile is adjusted by a rotation of the screw thread carved on the monopile for the investigation of the natural frequency and moment. The impact lateral load is applied by the pendulum hammer, which falls at the fixed pendulum length and angle. For the analyses of the monopile behavior due to the impact loading, strain guages are symmetrically installed on the surface of the monopile in the axial direction. Experimental results show that the maximum moment increases with the increase of natural frequency of the monopile. In addition, the predicted natural frequencies of the model monopile are similar to the measured natural frequencies. This study demonstrates that the model monopile suggested in this study may be effectively used for the characterization of behavior of the monopile installed in the field.
A Study on the Revitalization of Disaster Prevention Education Programs
Seo, Jung Pyo ; Cho, Won Cheol ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 95~105
DOI : 10.9798/KOSHAM.2012.12.2.095
Education on disaster prevention, one of the Non-structural Disaster Countermeasures, is being carried out by many institutions such as the "Central Civil Defense and Disaster Prevention Institute", other central or local government and related-institutions, in compliance with Article 34 of the Disaster and Safety Management Basic Act. Disaster prevention education, however, has been facing a lot of problems, as people still do not have enough educational opportunities to expand their skills in the field of disaster prevention. For example, lack of infrastructure such as educational facilities, experimental spaces and equipment has been an issue as well as the participatory learning methods such as tabletop exercise, role play, and field experience have not yet settled down. In other hand, traditional teaching methods such as supplier-oriented education are still the ones prevailing, therefore, it is not easy to obtain good results in disaster prevention education. In this sense, this study investigated the current problems in disaster prevention education, and sought ways to revitalize specific programs as means of enhancing the disaster prevention capabilities as followings. Firstly, this study emphasizes the importance of enactment of 'Act for Revitalizing Education and Training Experts in Disaster Prevention'. Secondly, it presents a way of enhancing educational infrastructure through the organizational extension of the existing National Disaster Management Institution. Lastly, it suggests the extension of consumer oriented educational curriculums and participatory learning methods along with constant feed-back system in disaster prevention education.
Assessment of Flood Vulnerability Considering Climate Change and Large-Scale River Restoration Project
Kim, Hwan Suk ; Park, Gi Jung ; Kim, Sang Dan ; Choi, Min Ha ; Park, Moo Jong ; Yoon, Jae Young ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 107~113
DOI : 10.9798/KOSHAM.2012.12.2.107
Damage caused by natural disasters has been increasing throughout the world due to climate change. As part of adaptation strategies, concept of vulnerability to climate change is introduced abroad to identify flood hotspots and to establish improvement measures. However, there has been very few research on vulnerability domestically. In addition, vulnerability studies conducted at a country level was also reported to be unsuitable for sub-country level. In this study, we conduct vulnerability assessment using entropy method for the Nakdong River Basin as part of domestic application. Vulnerability for present condition are first determined, and then changes in vulnerability due to climate change and large-scale river restoration project to identify their impacts. To achieve this, proxy variables that make up the vulnerability index were selected based on literature survey and data availability. Using data collected for this area, weights for proxy variables were then determined by entropy method. Finally, vulnerability was calculated and mapped for the basin. Reviewing the vulnerability maps showed that vulnerability hotspots were consistent with historical flooded areas for present condition. This suggests that the methodology employed is reasonable. The results for future scenario also showed that there were areas where vulnerability is mitigated by the large-scale river restoration project but also increased by climate change. However, the effect of the project in the future is found to be minimal because the decrease in water level by the project is offset by the increase in runoff due to climate change. The methodology presented in this study is thought to be useful in establishing the disaster prevention plan and climate-change adaptation policy by identifying hotspots.
Improvement In the Determination of the Investment Priority for Collapse Hazard Areas
Heo, Bo Young ; Choi, Woo Jung ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 115~119
DOI : 10.9798/KOSHAM.2012.12.2.115
In this study, we suggested an improvement methodology in determining the investment priority for collapse hazard areas using the quantitative analysis on the investment effect for the damage area criteria. Eleven areas were selected for the analysis in order to consider historical disaster records, and analyzed the its effect using the benefit cost analysis based on the damage area design criteria. Damage areas using steep slop standard and numerical simulation standard (rockfall 4.0) are established, calculated in terms of benefit cost analysis on damaged areas using the guideline for the recovery of natural disasters, disaster insurance, statutory standard price of fair market value, traffic congestion costs, and studied the benefit cost analysis in collapse hazard areas. Results of this study can be used to improve the determination of the investment priority for collapse hazard areas.
An Analysis and Study on the Change of Forest Fire Technigue in Korea
Lee, Si-Young ; Yun, Hoa Young ; Sung, Joon Kyung ; Park, Houng Sek ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 121~129
DOI : 10.9798/KOSHAM.2012.12.2.121
In this study, we studied and analyzed the change of forest fire policies in order for helping to improve a established forest fire policies. We divided into 7 periods for easier analysis. The first period was 'the period of pre-establishing the Korea forest service after independence (1945-1966). And the second was 'the period of pre-basic plan of forest' after establishing the Korea forest service(1967-1972). The third was 'the period of the first basic plan of forest'(1973-1978). The forth was 'the period of the second basic plan of forest'(1979-1987). The fifth was 'the period of the third basic plan of forest'(1988-1997). The sixth was 'the period of the forth basic plan of forest'(1998-2007). And the seventh was 'the period of the fifth basic plan of forest'(2008-present). In the result, the fire fighting organization, system and techniques was made rapid progress after Goseong forest fire in Kangwon region in April 1996. For future large scale forest fire attacking, the establishment of more systematical regional forest fire action plan and exercise from this would be needed.
An Experimental Study on the Manufacturing Technology Materials and Incombustible Function of Light-weight Concrete Panel used Bottom Ash
Oh, Jae Hoon ; Park, Sun Young ; Lee, Jae Wook ; Park, Hyo Suk ; Moon, Jong Wook ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 131~137
DOI : 10.9798/KOSHAM.2012.12.2.131
The higher and bigger buildings are, the huger the scale of fire is. As the height of buildings gets greater, the amount of lightweight concrete increases to be used for dividers and separation wall taking the weight of the building into consideration. In particular, in the case of using only materials for weight lightening, at a fire, expansion, explosive fracture and emission of toxic gas would occur, so damage of life and property is concerned. For this reason, in this research, we studied light weight materials which used Bottom Ash, a byproduct of a thermoelectric power plant, as main materials, instead of imported light weight materials. Through the manufacturing technology coating more than 5 mm Bottom Ash particle with less than 3 mm Bottom Ash particle, the air hole, the advantage of Bottom Ash, is maintained, and the absorption, the disadvantage of it, is improved. As a result, it satisfied all the requirement such as the absorption, compressive strength, and unit weight like the basic light weight concrete panel, and the absorption is improved by more than 50%, compared to Non-Coating Bottom Ash. In the experiment of incombustibility, we also studied great manufacturing technology of light-weight-concrete passed through KS F ISO 1182,2271(incombustible materials).
Measurements of Flow-Rate with Korean for Performance Based Egress Safety Design
Youn, Ho Ju ; Hwang, Eun Kyoung ; Kim, Jong Hoon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 139~143
DOI : 10.9798/KOSHAM.2012.12.2.139
In recent times, high rise and complex buildings have raised concerns about fire damage. In most developed countries, the performance basis evacuation safety design is established by the characteristics of the buildings and their' occupants. Especially, the run-off coefficient is the major evacuate factor in determining the time required in case of fire and, the foreign countries suggest the standard and the process of the run-off coefficient through accumulated fire accident experiences and experimental analysis. However, performance based fire protection design is recently introduced to domestic and, the studies and standards inthe emergency situation are insufficient. In addition, it is limited to secure the reliable evacuation capacity when applying the international standards due to the different evacuation characteristics of the domestic occupants (escape behavior, physical size and socio-cultural situation). Precedent studies on the domestic occupants' evacuation characteristics are required to secure the safer and more efficient domestic buildings evacuation safety. Therefore, in this study, the experiment set was builtto obtain the run off coefficients in the evacuation elements to establish the domestic building evacuation safety design and run-off coefficient experiments with the domestic age-categorized groups were conducted. These experiment scan be used as a basis for establishing the run-off coefficients of performance evacuation safety design in future.
Development of Web Based Realtime Water Pollution Accident Response Management System in Rivers
Mun, Hyun-Saing ; Jang, Ju-Hyoung ; Ryu, In-Gu ; Kim, Joo-Young ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 145~150
DOI : 10.9798/KOSHAM.2012.12.2.145
In Korea, around 25 oil and chemical water pollution accidents take place every year. In case of middle or large chemical spill in river, not only field response but also forecasting for the arrival time and diffusion concentration is important. However, the nation's forecasting ability using the hydrodynamic and water quality model is still in its infancy. For example, when fire occurred at the petrochemical plant in Kimcheon in 2008, forecasting error of arrival time for phenol prevented intake plants from taking proper measures in advance. In particular, as river flow characteristics have greatly changed following the construction of the weirs in four major rivers, we need to take into account weir management for prompt water pollution accident response. To this end, National Institute of Environmental Research developed the Water pollution Accident Response Management System (WARMS) for four major rivers. This system is designed not only to forecast arrival time and diffusion concentration in a timely manner using its automatic update of EFDC hydro module, but also to conduct scenario modeling using weir-connected operation. This study introduces the WARMS characteristics and evaluates the performance of the system using a phenol-spill simulation.
Analysis of Effect of Roughness Coefficient on Numerical Simulation for Stream Flow
Bae, Jae Seok ; Shin, Choong Hun ; Lee, Jang-Choon ; Yoon, Sung Bum ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 151~158
DOI : 10.9798/KOSHAM.2012.12.2.151
For the determination of the appropriate roughness coefficient applied to the dimensional models to analyse the stream flow, various numerical simulations with a straight channel, a straight channel with obstructions, and a meandering channel were performed using HEC-RAS as one-dimensional model, RMA2 as two-dimensional model, and FLOW-3D as three-dimensional model with a same Manning's n-value. From the simulation results it was found that each model gives different water surface profiles, even though the same roughness coefficient applied to the one-dimensional model was used for the two-and three-dimensional models. Based on the mechanism analyses of the numerical results it was found that the energy loss due to two-or three-dimensional flow effect is considered twice in the two-or three-dimensional model. Thus, the Manning's n-value required for the numerical computation of stream flow is different according to the numerical model adopted, the grid or mesh system and the flow characteristics, and it should be adjusted through the comparison between the observed and calculated surface profiles.
Ensemble Prediction of Future Design Rainfalls Considering Climate Change
Seo, Lynn ; Jeon, Myeonho ; Kim, Tae-Woong ; Kim, Sangdan ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 159~171
DOI : 10.9798/KOSHAM.2012.12.2.159
This study proposed a practical approach to estimate design rainfalls that can be applied to design reference year using the relationships among distribution parameters, annual rainfalls estimated from GCMs(Global Circulation Models), and annual maximum rainfalls observed at gauging stations, leading to consider climate change. The highlight of this study is to estimate distribution parameters through regression models with annual rainfalls as a causal factor. The proposed model was applied to estimated ensemble design rainfalls with 24-hr duration in built-up design reference years of 2020 and 2030 at 10 stations considering the uncertainty induced by emission scenarios and GCMs. The overall results indicated that the design rainfalls of Gangneung, Daejeon, Seoul, and Sokcho in 2020 and 2030 are higher than those in 2009(assumed as the current), the design rainfalls of Gwangju, Seosan, and Jeju in 2020 and 2030 are very close to the current, and the design rainfalls of Busan, Mokpo, and Daegu in 2020 and 2030 are lower than the current. It is considered that the trend component of the annual maximum rainfalls is incorporated into the process of estimating design rainfalls. The proposed method can provide design rainfalls in the next 10 more years in which the effect of climate change is reflected, and thus may suggest useful reference or alternatives for the hydrologic plan and management.
Parameterization Analysis of SWAT Model Considering the Uncertainty
Cho, Hyoung Jin ; Jeong, Dong Kug ; Choi, Yong Jun ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 173~180
DOI : 10.9798/KOSHAM.2012.12.2.173
Recently in Korea, there has been interested in retaining sustainable water resources as a strategy to cope with climate change. To do that, a more accurate flow estimation is needed. In general, the watershed runoff in a basin is estimated by rainfall-runoff model. However, many kinds of uncertainties in these models make much harder to estimate accurate runoff. Thus, the SUFI-2 algorithm was used to reduce the potential uncertainty in the process of building rainfall-runoff model. The SUFI-2 algorithm has the advantage of combining an optimization concept and being able to handle multiple parameters at once in uncertainty analysis. As a target basin, Cho-river having tremendous impact on Geum-river flow rate and as a rainfall-runoff model, the SWAT model widely used recently was selected. In the result of the optimal parameters of the SWAT model to the target basin using SUFI-2 algorithm, the parameters having the most influence on the outflow were in the following order, "Plant uptake compensation factor", "Available Water Capacity of the Soil Layer", "Runoff curve number in moisture condition II" and "Critical depth of water in the shallow aquifer required to get back(GWQMN.gw)".
A Study on Simulation of Dam-Break Wave Using a Three-Dimensional Numerical Model
Jeong, Woo Chang ; Lee, Jin Woo ; Cho, Yong-Sik ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 181~192
DOI : 10.9798/KOSHAM.2012.12.2.181
In this study, the simulation of the flood wave due to the dam failure is carried out using a three-dimensional numerical model. The applied numerical model is ANSYS CFX (Ver. 13.0) which is a commercial software developed by ANSYS Inc. This numerical model is applied to three different cases of hydraulic model experiments related to the analysis of the dam-break wave, and the results simulated from three-dimensional model are compared and analyzed with those from laboratory measurements and the two-dimensional numerical model. As results of comparison, the predicted results agree well with measured ones and are more slightly accurate than those from the two-dimensional numerical model. In particular, the peak water depth and its time agree almost accurately with measured ones. Therefore, we can expect that the three-dimensional numerical model applied in this study could be effectively applied to predict the peak water depth and its time after a dam failure.
Analysis of Long-term Runoff Reduction Effects by Installation of Street Tree Box
Joo, Jin Gul ; Lee, Yu Hwa ; Cho, Hye Jin ; Kim, Joong Hoon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 193~197
DOI : 10.9798/KOSHAM.2012.12.2.193
A simulation technique using storage unit of SWMM was suggested to estimate capacity of infiltration facilities. Using the suggested method, runoff reduction effect of tree box type infiltration facility was simulated for single and long-term continuous events. As the results, an efficiency of infiltration facility was affected by not only rainfall intensity, but also continuous rainfall characteristics like dry days, antecedent rainfall volume, and so on. The facility was capable of 10 percent runoff reduction, which was expected to reach 144.4 mm or 98,533 at the study area. In the short run, a water control effect like peak discharge reduction and an environmental effect like first flush capture is expected by installation of the facilities. In long term, the facility can contribute to recovery of healthy hydrologic cycle like increasing the ground water level and preventing dry stream at urban areas.
Analysis of Rainfall-Flood Severity Relations in Small Ungauged Catchments
Kim, Eung Seok ; Jang, Hoyun ; Kim, Sangdan ; Park, Moo Jong ; Choi, Hyun Il ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 199~208
DOI : 10.9798/KOSHAM.2012.12.2.199
As extreme floods occur frequently in recent years due to global climate changes, an increase in sudden local flooding of great volume and short duration is becoming the significant danger and loss of life and property in the Korean Peninsula as well as most parts of the world. Since such a local flood rises quite quickly with little or no advance warning to prevent flood damage, this study has developed a new flash flood index for the use in small ungauged catchments. The flash flood index is obtained by relative severity factors estimated in ratios for hydrograph characteristics of each flood event to those of the highest recorded maximum flood. Flood runoff hydrographs for the two selected small ungauged basins are generated from a rainfall-runoff model for the annual maximum rainfall series of long-term observed data. The aim of this study is to present the best-fit regression equation with the high coefficient of determination between the flash flood index and rainfall characteristics to provide the basis database for forecasting a local flood severity directly from rainfall data in small ungauged catchments. The regression results in this study show that the proposed flash flood index has a very high relation to a certain rainfall pattern for both study basins. It is therefore expected that the regression equations between the new flash flood index and rainfall characteristics can provide better understanding of the hydrologic behavior of local flash flooding using rainfall patterns in small ungauged catchments.
Evaluation Method of Urban Inundation Risk using Multi Criteria Decision Making Method
Song, Yang Ho ; Lee, Jung Ho ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 209~214
DOI : 10.9798/KOSHAM.2012.12.2.209
In this study, Entropy method and PROMETHEE(Preference Ranking Organization METHod for Enrichment Evaluations) which is one of the multi criteria decision making methods are applied to estimate the relative inundation risk of the urban subcatchment. For this purpose, several factors which have an effect on the inundation risk are selected and used to perform PROMETHEE. Those are elevation average, slope average, width and population, density of conduit of each subcatchment. Based on them, PROMETHEE is performed and the relative urban inundation risk for each subcatchment is estimated. For the validation of the suggested method, the results from the suggested method are compared with the historical inundation records occured on 1990 and the relative urban inundation risk estimated. From the comparison, it is found that the suggested method may generate better results to estimate the relative urban inundation risk of each subcatchment than the method considering sediment yields per unit area only. Also, it can be applied to establish a rehabilitation order of subcatchments for mitigating the inundation risk.
Evaluation of Rainfall Measurement Capability of Dual Polarization Radar
Jeon, ByeongKuk ; Lee, ChoongKe ; Kim, YangSu ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 215~224
DOI : 10.9798/KOSHAM.2012.12.2.215
The information of areal rainfall distribution is very important for the flood forecasting, flood management, and dam operation, etc. In analyzing of spatial distribution of rainfall, the rain radar is superior to the point rain gauge network and has been used for flood managements in many countries. In Korea the rain radar is used for rainfall estimation and recently 'Ministry of Land, Transportation and Maritime Affairs' is operating the first dual polarization rain radar at Mt. Bisl, Daegu. In this study the applicable feasibility of dual polarization rain radar to flood forecasting was reviewed through evaluation of rainfall measurement capability, comparing to the conventional single polarization radar, for major heavy rain events occurred within Nakdong river basin in 2011. As a results the mean observational error, comparing to the surface rain gauge as ground truth, by dual polarization radar was decreased about 13% from the one of single polarization radar. From the study the feasibility of radar rainfall to improving flood forecasting accuracy was revealed.
Development of a Reliability Estimation Method for the Storm Sewer Network
Lee, Jung Ho ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 225~230
DOI : 10.9798/KOSHAM.2012.12.2.225
The reliability of storm sewer network is estimated by the probability of system failure as the general structure systems. And the current researches for the system reliability have been based on the uncertainty analysis. However, these researches consider only the failure probability based on mathematical analysis in the sewer design but does not consider the situations caused by the system failure. In this study, the suggested method, RSDMM(Reilibility of Sewer system using DMM), evaluates the reliability of storm sewer network considering the situation of the network failure. In this method, the system failure was defined as the overflow occurrence in the sewer system for the rainfall events. And the parameters to estimate the reliability are the overflow volume and the number of the overflow manholes in the storm sewer network. In order to estimate the reliability, this method used the Distance Measure Method (DMM). DMM is the method to estimate the distance between the parameters while the units and dimensions of each parameter are different. Therefore, the suggested RSDMM can produce the quantitative evaluations about the relative superiors among the sewer systems using the results of the system failure simulations.
Non-stationary Frequency Analysis for Extreme Precipitation based on Representative Concentration Pathways (RCP) Climate Change Scenarios
Sung, Jang Hyun ; Kim, ByungSik ; Kang, Hyun-Suk ; Cho, ChunHo ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 231~244
DOI : 10.9798/KOSHAM.2012.12.2.231
Due to the Climate Change and Climate Variability in the world, the temperature, precipitation, evaporation etc, hydrologic cycle components are changing rapidly compared with the past. Previous researches have presented many results of extreme hydrological events and frequency increases. In Korea, during latest 10years (1999~2008), the frequency of localized heavy rain above 100 mm in a day occurred totally 385 times, compared 1970~80s when the frequency was 222 times, it increased 1.7 times. For 2011, from early July to mid-August, due to the rainy season and localized heavy precipitation, the accumulated precipitation reached 1285.3 mm. In Seoul and metropolitan areas, the localized heavy precipitation over design precipitation of 100year frequency happened, causing widely flooded area and causing property damage and human casualties in the downtown area. According to the latest extreme flood moved to upper tail of existing probability density function, it is expected that future flood damage frequency and intensity will increase comparing present situation. In this paper, in order to project the future influence of extreme flood of the Korean peninsula, comparing the IPCC 5 Report (AR5), according to the Representative Concentration Pathways (RCP), newly promoted and simulated regional climate model was applied to summary precipitation and considering to the exterior factors, the non-stationary frequency analysis was performed. This result range across the South Korea areas, and the whole increase of extreme precipitation was checked. Especially, following to RCP 4.5 and 8.5 parts, the future 20year frequency average would be reduced to 12.5years, 11.9years separately in the place, so it is expected that the flood safety will be reduced.
A Study on the Assessment Method for High-risk Urban Inundation Area Using Flood Vulnerability Index
Park, Minkyu ; Song, Youngseok ; Kim, Sangdan ; Park, Moojong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 245~253
DOI : 10.9798/KOSHAM.2012.12.2.245
Due to urban population growth and increase of impervious ratio, backwardness of major infrastructure, increased rainfall intensity in climate change, and so on, the risk of flood damage in urban areas is increasing. In order to establish measures for this, quantitative analysis for flood damage that occurs in urban areas is needed. In this study, a methodology assessing high-risk areas vulnerable to flooding in units of drainage catchments by comparing the city's flood zone and flood vulnerability factors is proposed. Using flood damage data, the city's flood zone is delimited by inundation area and inundation frequency to be analyzed. Taking into account the ease of date collection, lowland areas, lack of sewer discharge capacity, imperviousness, and runoff curve number are selected as the flood vulnerability factors. As an application, high-risk drainage catchments vulnerable to flooding in Juanang stream watershed are identified.
Prediction of design water level due to storm surge at the Seogwipo Coastal Zone
Moon, Seung Rok ; Kang, Ju Whan ; Park, Seon Jung ; Shim, Jae Seol ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 255~261
DOI : 10.9798/KOSHAM.2012.12.2.255
Seogwipo coastal zone is the area where they develop marine tourism resources, and extend port facilities. However, the area is in concern for great damage since it is in the area of most typhoon paths to Korea. This study analyzes the characteristics of the Jeju coastal zone through analysis on significant weather elements, such as typhoons. This research also examines the design water level by the storm surge of the Port Seogwipo. The design water level was calculated frequency analysis, including the highest water level, surge height by time, observed storm surge height at the approach of a typhoon, and the storm surge height by the result of numerical simulation. It also suggests the problem that cannot reflect the recent dramatic climatic changes. To settle, it is needed to use it in actual work-site operations through constant data management and numerical simulation of storm surges.
Hazard Map with Probable Maximum Tsunamis
Park, Kang-Wook ; Cho, Yong-Sik ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 263~270
DOI : 10.9798/KOSHAM.2012.12.2.263
During last decades, several major earthquakes and subsequent tsunamis have been occurred in the East Sea surrounded by Korea, Japan and Russia. These tsunamis caused devastating damage to coastal areas not only in Japan but also along the Eastern Coast of Korea. It is important to establish a countermeasure against tsunamis based on fundamental researches, such as field survey and numerical simulation. In this study, a concept of probable maximum tsunami is firstly proposed. The probable maximum tsunamis are consisted of 3 historical and 11 virtual tsunamis. An inundation area is then predicted based on probable maximum tsunamis and a tsunami hazard map is also produced. The produced tsunami hazard map can be used by the local authority in the event of real tsunami attacks.
Tsunami Hazard Area at Imwon Port Determined by Probability Plot Correlation Coefficient Test
Kim, Yong Cheol ; Cho, Yong-Sik ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 271~277
DOI : 10.9798/KOSHAM.2012.12.2.271
Recently, catastrophic tsunamis triggered by impulsive undersea earthquakes have occurred frequently subduction zones around the Pacific Ocean. These tsunamis have caused loss of human lives and devastating property damage. Thus, proper countermeasures to mitigate tsunami damages should be made. To increase the efficacy of the tsunami disaster prevention policy, a tsunami hazard area at Imwon Port is determined by using a probability concept. The probability of the simulated tsunami flooding exceeding a prescribed criterion is calculated at each grid point of an inundated area. To calculate the flooding probability, a probability distribution type is determined by probability plot correlation coefficient(PPCC) test. The calculated flooding probability agrees reasonably with the distribution tendency of the maximum flooding height.
Long Term Operation of Laboratory Nitritation Reactor Using Anaerobic Digester Supernatant of Municipal Wastewater Treatment Plant and Piggery Wastewater
Gil, Kyungik ; Im, Jiyeol ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 279~286
DOI : 10.9798/KOSHAM.2012.12.2.279
In this study, the laboratory scale reactor was operated for high strength ammonium nitrogen in anaerobic digestion supernatant and piggery wastewater through nitritation that is an innovative process of nitrogen removal. From the laboratory scale reactor for about 970 days, a stable nitritation was induced, and the operation factor of induced was analysed nitritation. As a result, a stable nitritation could be successfully induced from anaerobic digestion supernatant and piggery wastewaters. It appeared that nitritation wasn't affected seriously within the range of pH, Alkalinity and COD in influent. In case of SRT, it found that nitrite conversion rate was changed according to SRT condition change, so it showed that SRT had effected on nitritation. In addition, compared to ammonium nitrogen removal, it clearly revealed that nitrite conversion rates more sensitive to SRT. The conclusion in this study, it could be used as an important data when applying nitritation to municipal wastewater treatment plants(MWTPs).
Stabilization of Heavy Metal Contaminated Paddy Soils
Cui, Mingcan ; Na, Sengmin ; Khim, Jeehyeong ; Jang, Min ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 287~292
DOI : 10.9798/KOSHAM.2012.12.2.287
In this study, the stabilization treatment efficiency of coal mine drainage sludge (CMDS), waste cow bone (WCB) and waste oyster shell (WOS), which mainly contain
and CaO, respectively, was estimated for ordinary and paddy fields contaminated with arsenic, lead and other heavy metals. After mixing the contaminated soils completely with stabilization materials, the samples were preserved with moisture for 28 days. The extraction of As, Pb, Cu, Zn and Cd for ordinary soils stabilized by CMDS(wt. 15%) and WOS(wt. 5%) were 5.1, 0.12, 0.33, 2.28 and 0.25 mg/kg, respectively, satisfying the concerned limit for 'Ga' region established by the Ministry of Environment at 2009. The extracted arsenic concentrations of paddy soils stabilized by CMDS(wt. 20%), CMDS(wt. 10%)/WOS(wt. 5%), CMDS(wt. 15%)/WOS(wt. 5%), and CMDS(wt. 10%)/WOS(wt. 10%) were 1.6, 3.52, 2.2 and 2.42 mg/kg, respectively. These results also satisfied the concerned limit for 'Ga' region.
Delivery Rate Estimation for the TMDL Management of Soyang Lake Basin
Park, Soo Jin ; Choi, Han Kuy ; Han, Yang Soo ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 293~301
DOI : 10.9798/KOSHAM.2012.12.2.293
The study aimed at observing the delivery characteristics of pollutant loadings by calculating the delivery rate of drainage areas on the pollutant item in the basin of Soyangho that is the biggest multipurpose dam in the upper region of the Bukhan River. According to the result of the observation on the delivery characteristics of pollutant loadings depending on the flow regime change, the delivery rate increases in BOD, SS and T-P. In case of T-N, the delivery rate increases in Naerincheon, Bukcheon and around Hapgang city where there are many point pollutant sources. The delivery rate generally increases during the period of ninety-five day flow and high water flow. In case of Soyangho, the delivery curve shows a gentle slope when lower ninety-five day flow compare to tributary channels, which indicated the continuous discharge of pollutants during the period of base flow. In addition, the delivery rate duration curve depending on the amount of discharge was recorded, which can be utilized to establish TMDL management's objective of water quality and to decide.
Determination of Urban Watershed Boundary and Optimal Design of Sewer Networks using Multi-objective Optimal Technique
Lee, Jung Ho ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 303~307
DOI : 10.9798/KOSHAM.2012.12.2.303
The increasing incidence of torrential rain and the increment of impervious area caused by urbanization has increased the surface flow and decreased the time of concentration. Therefore, the peak outflows and urban inundation risks are increased in urban areas, so that the sewer system must be designed to minimize the inundation risk in urban areas. In this reason, the suggested Optimal Sewer layout and Watershed division Model (OSWM) determines the optimal sewer layout and basin boundary considering "minimum peak outflow" at outlet in the sewer network to reduce the urban inundation risk. The OSWM determines the optimal design considering peak outflow at outlet and rehabilitation cost of sewer network. Then, the peak outflow and rehabilitation cost are minimized, so that the urban inundation risk is decreased due to the peak outflow reduction. In this model, NSGA-II (Non-dominated Sorting Genetic Algorithm) which is one of the multi-objective optimal techniques was used to solve this multi-objective problem. The OSWM was applied to a multi-outlet urban area containing two sub-basins in Seoul, South Korea. According to the basin boundary and sewer networks determined from OSWM, the peak outflows at each sub-basin outlet were decreased by 26.6% for the design rainfall event of 10-year frequency.
Analysis on the Characteristics of Exceeding Probability Rainfall Events
Jo, Deok Jun ; Jeon, Byeong Hoon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 2, 2012, Pages 309~313
DOI : 10.9798/KOSHAM.2012.12.2.309
The present paper describes applicability in practice for the design rainfall by the analysis of characteristics of the probability rainfall. In general, the size of hydraulic structures is determined by the rainfall suitability of the design rainfall is very important. To this end, in the last 50 years historical hourly rainfall data for each return period and duration of rainfall issued by more than the probability for rainfall occurrence and rainfall characteristics such as size and periodicity causes were analyzed. In addition, the annual trend of average rainfall events greater than the probability were analyzed. This study shows excess rainfall caused by the number of occurrence of rainfall return period were much more than that, the average rainfall exceeds the rainfall was growing up. Therefore, to adopt the probable rainfall as the design rainfall can not meet the flood protection as it aims.