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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 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 the Seismic Retrofit Techniques of School Buildings Constructed in Accordance with Standard Design in 1980s
Kang, Jong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 1~7
DOI : 10.9798/KOSHAM.2012.12.1.001
We considered the practical aspects to the seismic performance evaluation method and adopted a numerical approach using a universal program, MIDAS-GENw applied the KBC-structural design standards 2009. The four types such as reinforced concrete shear walls and X-type, K-type, and knee-type steel braces were chosen to the seismic retrofit techniques. The results were summarized as follows: First, the results of a numerical approach to the performance evaluation according to the seismic retrofit techniques, the excellence of the seismic performance was in the order of reinforced concrete shear walls and X-type, K-type, and knee-type steel braces. Second, when installing the shear walls in 24 places among 65 places that can enhance in the direction of X and in 11 places among 49 places that can enhance in the direction of Y, in the case of the four-story school building the structural reinforcement by the action of the earthquake loads in the existing beams and the columns framing may not be require.
Experimental Study on the Compressive Strength and Behavior of yLRC Composite Columns Supplemented by Inner Braces
Kim, Myeong Han ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 9~15
DOI : 10.9798/KOSHAM.2012.12.1.009
Compressive strength tests on yLRC (Reinforced Concrete with y-shape steel sheets and L-shape steel angles) composite column supplemented by inner braces are performed. Although axial compressive strength tests of Non-supplemented yLRC column were performed, in the previous study, the columns showed comparatively sudden strength reduction after peak load. This study aims to verify ductile behaviors of the supplemented yLRC columns beyond the maximum load and to examine the suggested equation for calculating the compressive strength of the composite column. The experimental variables of this study are 1) the existence of inner braces, 2) the type of inner braces and 3) the number of inner braces. Total of six specimens having practical section size are fabricated for concentrically axial load test. Based on the test results, the axial behavior of the supplemented yLRC composite column are analysed and the applicability of the suggested equation is examined.
Elasto-Plastic Analysis Using the Generalized Finite Element Method with Global-Local Enrichment Functions
Han, So Jeong ; Kim, Dae Jin ; Lee, Chang Joon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 17~22
DOI : 10.9798/KOSHAM.2012.12.1.017
This paper presents a procedure to numerically generate proper enrichment functions for three-dimensional elasto-plastic problems. This procedure involves the solution of boundary value problems around local regions exhibiting nonlinear behavior and the enrichment of the global solution space with the local solutions through the partition of unity method framework. This approach can produce accurate nonlinear solutions with a reduced computational cost compared to standard finite element methods since computationally intensive nonlinear iterations can be performed on coarse global meshes after the creation of enrichment functions properly describing localized nonlinear behavior. A three-dimensional nonlinear problem based on the rate-independent
plasticity theory with isotropic hardening is solved using the proposed procedure to demonstrate its robustness and accuracy.
A Study on CFD Simulation for Fire Spread of Residential Compartment
Ahn, Chan Sol ; Kim, Heung Youl ; Yoo, Yong Ho ; Cho, Kyung Suk ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 23~29
DOI : 10.9798/KOSHAM.2012.12.1.023
A revised Korean Fire Code is operating based on performance design method and Korean Building Code has been also adopted to performance design method. A real fire scale test has some limitations of scale, environment and cost. For studying the variety of fire situations, we could use computer simulation method. In this study, computer simulation was performed for compartment fire based on data obtained real fire scale test of compartment. And we compared the real fire scale test data and simulation data for flame growth rate, heat release rate, total heat release and temperature. From the simulation results, the flame growth rate was over predicted of 12 percent, the heat release rate was over predicted of 11 percent, the total heat release was under predicted of 50 percent and the maximum temperature of compartment was under predicted of 7 percent than real fire scale tests.
A Development of LQI(Living Quality Indicator) System for High-rise Residential Building
Kim, Jin Wook ; You, Yong Hum ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 31~37
DOI : 10.9798/KOSHAM.2012.12.1.031
In Korea, high-rise residential building is becoming common house type of CBD Area and some project is going on design over 100 stories residential buildings. Considering this situation, living quality of high-rise residential building is becoming important. Therefore countable design evaluating factors for high rise residence should be needed to ensure a pleasant and healthy environment. In this research, DQI(Design Quality Indicator) which is a objective system to assess public space design was reviewed. And LQI(Living Quality Indicator) is proposed to evaluate space and living quality for high rise livings. First of all, algorism of system was established and design indexes frame for living space of high rise multi use residence building was designed. After evaluation elements were established, evaluation elements were verified by Delphi Method inspection to professional group.
Buckling Behavior of Longitudinally Stiffened Steel Plates by U-Shaped Ribs
Choi, Byung Ho ; Choi, Su Young ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 39~44
DOI : 10.9798/KOSHAM.2012.12.1.039
Even though the longitudinally stiffened plates with closed section ribs should be an effective system for axially compressed members, the current design speculations on closed-section rib, especially for the minimum required stiffness, are not sufficient. This study is aimed to examine the influence of the sectional stiffness of U-shaped ribs on the buckling modes and strengths of stiffened plates. Applying three kinds of U-ribs, 3-dimensional finite element models for the U-rib stiffened plates were setup by using ABAQUS and then a series of eigenvalue analyses were conducted. From the parametric studies, it was found that the minimum required stiffness as well as the buckling strengths are varied along with the U-rib types. The buckling strengths were compared with the theoretical critical stress equation for simply supported plates. This study will contribute to the future study for evaluating the minimum required stiffness and optimum design of U-rib stiffened plates.
Analytical Evaluation of Bond-Slip Behavior at the Interface between FRP and Concrete Using Commercial Numerical Bond-Slip Subroutine Model under Freezing-thaw Cycle Environment
Jung, Woo Young ; Kim, Nam Jung ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 45~51
DOI : 10.9798/KOSHAM.2012.12.1.045
This research presents an analytical evaluation of the long-term bonding behavior at the interface between concrete and FRP under freeze-thaw environments and overall structural performance in the RC structure reinforced by FRP. To predict overall structural performance of the structure, a nonlinear bond-slip subroutine is proposed and verified for its availability with comparison of the previous experimental results. Finally, analytical results indicate that the maximum stress of the interface and the surface stress on the FRP skin plate were reduced gradually under freeze-thaw environments. It is evidence that the bonding capacity at the interface between concrete and FRP may be decreased as the exposure for the freeze-thaw environments is increased. To make more accurate results, more advanced works for analytical subroutine are performed and experimental results will be compared and discussed in the future.
Inelastic Lateral-Torsional Buckling Strengths of Stepped H-Beams with Noncompact Flanges Subjected to Pure Bending
Son, Ji Min ; Park, Jong Sup ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 53~60
DOI : 10.9798/KOSHAM.2012.12.1.053
This paper investigates inelastic lateral-torsional buckling of doubly and singly stepped beams with noncompact flange subjected to pure bending. A three-dimensional finite-element program ABAQUS(2007) and a regression program MINITAB(2006) were used to analytically develop new design equation. Ratios of flange thicknesses, flange widths, and stepped lengths of the beam based on a typical section of
were considered as analytical parameters. Two groups of 27 and 36 cases for doubly and singly stepped beam, respectively, with a total of 252 case, were analyzed in the inelastic buckling range. The combined effects of residual stresses and geometrical imperfection on inelastic lateral-torsional buckling of beams are considered. The new proposed equation will definitely improve the current design methods for the inelastic lateral-torsional buckling problem and will increase the efficiency in building and bridge design. The solution can be easily used to develop new design equations for inelastic lateral-torsional buckling resistance of stepped beams subject to general loading condition such as a concentrated load, a series of concentrated loads or uniformly distributed load.
A Study on Inelastic Lateral-Torsional Buckling Strengths with Load Height Effects
Park, Yi Seul ; Oh, Jeong Jae ; Kim, Kyu Sun ; Park, Jong Sup ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 61~67
DOI : 10.9798/KOSHAM.2012.12.1.061
This paper investigates inelastic lateral-torsional buckling strengths of I-beams with load height effects. The combined effects of residual stresses and geometrical imperfection on inelastic lateral-torsional buckling of beams are considered. The distribution of the residual stress in the cross-section is same as shown in Pi and Trahair(1995). The initial imperfection of the beam is set by a central displacement equal to 0.1% of the unbraced length of the beam. New moment gradient factors for load height effect of inelastic beams are very similar to the results from finite element analyses. The proposed equations will greatly contribute to calculate the inelastic lateral torsional buckling strengths with load height effect.
Vibration Characteristics of Real Caisson-Type Breakwater by Wave-induced Micro-Vibration Monitoring
Lee, So Young ; Kim, Jeong Tae ; Yi, Jin Hak ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 69~74
DOI : 10.9798/KOSHAM.2012.12.1.069
In this study, the wave-induced micro-vibration monitoring scheme is proposed to analyze vibration characteristics of real caisson-type breakwater. To produce the basic information on vibration-based structural safety assessment of caisson structural system, the following approaches are implemented. Firstly, vibration response analysis methods are selected to examine modal characteristics of caisson structure. Secondly, Oh-Ryuk-do caisson-type breakwater is selected as the real caisson structure. Thirdly, wave-induced micro-vibration responses are measured by wireless acceleration measurement system. Finally, vibration characteristics of the real caisson are analyzed for the purpose of utilizing them for structural safety assessment and of evaluating the practicality of the proposed micro-vibration monitoring scheme for caisson-type breakwater.
Vibration-based Structural Health Monitoring of Full-Scale Cable-Stayed Bridges Using Wireless Smart Sensors
Ho, Duc Duy ; Lee, Po Young ; Lee, So Young ; Kim, Jeong Tae ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 75~81
DOI : 10.9798/KOSHAM.2012.12.1.075
In this paper, the applicability of a smart sensor system for structural health monitoring (SHM) is evaluated on a full-scale cable-stayed bridge. Firstly, vibration responses of pylon-cable-deck system in cable-stayed bridge are described. Secondly, an Imote2-based smart sensor system is designed for the vibration-based SHM. Finally, the practicality of the smart sensor system is evaluated on a real cable-stayed bridge, Hwamyung Bridge in Korea. The field-test bridge is briefly described and the field sensor deployment is outlined. The long-term monitoring performance of the sensor system is examined under various weather conditions. The experimental modal parameters of the target bridge are identified by numerical modal analyses. The accuracy of cable force monitoring by the sensor system is evaluated for the target bridge.
The Study on Aseismic Reinforcement Method for Existing Structures Based on Shaking Table Test
Park, Inn Joon ; Mha, Ho Seong ; Lee, Yong Kyo ; Yoo, Byung Jun ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 83~88
DOI : 10.9798/KOSHAM.2012.12.1.083
In this paper, the seismic performance on the aseismic reinforcement method for existing structures has been examined based on the shaking table test, to verify the aseismic improvement of the applied method utilized in the current constructions. To simulate the behaviors of the reinforced concrete frame structures, two identical specimens(with aseismic reinforcement method and without aseismic reinforcement method) are prepared for the test. Strain gages, accelerometers and LVDT are placed at the middle of the bottom, middle and the top of the column as well as at the middle in the upper girder. The shaking table tests are performed with the applied maximum acceleration from 30% to 150% of 0.15 g, which is the input artificial seismic excitations defined by the design spectrum. From the results, the specimen without retrofit is found to show 1mm crack at the position up to the 80 cm from the foundation while the specimen with retrofit is found not to show any crack under the Peak Ground Acceleration(PGA) 0.20 g. In the case of 0.11 g test, the specimen without reinforcement shows a much bigger variance in the strain than those found from the specimen with reinforcement. As the input PGA increase, the amplification ratios of response accelerations of the specimen without the reinforcement are found to be increased although those of the specimen with reinforcement are not quite changed. It could be concluded that the aseismic reinforcement method may give the large improvement in the seismic performance.
Analysis of Characteristics of Vertical Response Spectrum of Velocity Ground Motions from 5 Macro Earthquakes
Kim, Jun Kyoung ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 89~95
DOI : 10.9798/KOSHAM.2012.12.1.089
The vertical velocity response spectra, not acceleration, using the observed ground motion from the recent 5 macro earthquakes, larger than 4.8 in magnitude, were analysed and then were compared to both the seismic design response spectra (Regulatory Guide 1.60, 1968), applied to the domestic nuclear power plants, and the Korean Standard Design Response Spectrum for general structures and buildings(1997). 51 vertical ground motions were used and vertical response spectra were normalized with respect to the peak velocity value of each ground motion. The results showed that response spectrum has strong dependency on natural frequency or natural period. The results also showed that the vertical velocity response spectra revealed higher values for frequency bands below approximately 2 - 3 Hz than Regulatory Guide 1.60(1968), which were scaled to 0.1 g. The results were also compared to the Korean Standard Response Spectrum(500 years of recurrence rate) for the 3 different soil types(SC, SD, and SE) and showed that the vertical response spectra revealed higher values for the frequency bands above approximately 0.2 second (5Hz) than the Korean Standard Response Spectrum. Through the qualitative improvements and quantitative enhancement of the observed ground motions, it is necessary that the conservation of vertical seismic design response spectrum should be considered more significantly for the frequency bands suggested above.
Performance Evaluation of the Column-Coping Joint for Prefabricated DSCT Pier
Won, Deok Hee ; Han, Taek Hee ; Kim, Seung Jun ; Kang, Young Jong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 97~103
DOI : 10.9798/KOSHAM.2012.12.1.097
Recently, Technology of bridge construction has made great progress for reduction of construction period and Green Growth. The construction period of Pier had about 50% in construction period of entire bridge. Therefore, construction method of prefabricated piers have researched by many researchers, lately. In this paper, we suggested the joint of coping-column for prefabricated DSCT pier and verified by experimental study. To experimental study, the test methods had proposed for the performance characteristics evaluation of coping-column joint. Test methods were made up cyclic eccentricity loading test and static compressive loading test. We had produced the major parameters and suggested the standard model for joint of coping-column through the experimental study.
Assessment of Multi-functional Sealants Placed on the Penetration in Nuclear Power Plants
Cho, Nam Jin ; Im, Seok Been ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 105~110
DOI : 10.9798/KOSHAM.2012.12.1.105
The currently operating nuclear power plants have employed multi-functional sealants at the penetration in their auxiliary structures. In many cases, however, the physical properties such as fireproof, internal pressure, water tightness, and radiation shield of the sealants were not assessed properly when placed at the penetration. In addition, insufficient physical properties of the sealant at nuclear power plants have been continuously reported. Thus, this study assessed the physical properties of the sealant using a thermal aging and irradiation tests. To assess the physical properties, the density, compressive strength, and hardness of the sealants were examined before and after the thermal aging test and the irradiation test. Based on the experimental tests, the samples from the nuclear power plants are expected to satisfy the standard specifications after applying the possible thermal and radiation effects in 20 years.
Estimating the Effectiveness of Fog Detect & Warning System by Driving Simulator
Lee, Suk Ki ; Jeong, Jun Hwa ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 111~117
DOI : 10.9798/KOSHAM.2012.12.1.111
In a foggy day, visible distances depend greatly on the ever-changing concentration of fog. Most of chained rear-end collisions in a foggy day are caused by the significant differences in speeds between vehicles. Then, it is important to minimize the collisions in fog. This study is to estimate the effects of FDWS on drivers' safety behaviors by using a vehicle simulator and a questionnaire survey. A roadway section 1 km long with bidirectional 2 lanes was chosen for the estimation efforts. The test segment was from the Munsan to the Jeokseong county in National Highway 37. Scenarios associated with fog were set as heavy fog. Also, the distance between driver warning lamps was considered by 25 m and 30 m, respectively. The experiment conducted in this study employed the total of 31 adults who were randomly selected from 20- to 60-year old. Before performing the experiment, each subject had enough times to be familiar with the vehicle simulator and was instructed by the guideline of the experiment. After performing the main test, a questionnaire survey was undertaken for each subject.
Analysis of the Interaction between Curved Continuous Welded Rail Track and the Curved Bridge
Han, Sang Yun ; Han, Taek Hee ; Kang, Min Choul ; Kang, Young Jong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 119~126
DOI : 10.9798/KOSHAM.2012.12.1.119
The continuous welded rail (CWR) track reduces maintenance costs and increases passenger comfort etc. Although the CWR track has many advantages mentioned, the stability of the track is highly affected by change of temperature. Where the CWR track is over the bridge, the longitudinal force and displacement are occurred by the track-bridge interaction. To guarantee the stability of the CWR track, therefore, the analysis of track-bridge interaction should be performed. The UIC(2001) dose not suggests the method and the regulations of the curved track-curved bridge interaction but those of the straight track-bridge interaction. In this paper, the analysis technique of the curved track-curved bridge interaction is presented. The numerical analysis of the interaction between curved track and 2-span curved continuous bridge is performed.
GIS and Agent-based Modeling of Emergency Evacuation
Yu, Soon Young ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 127~132
DOI : 10.9798/KOSHAM.2012.12.1.127
Agent-based emergency evacuation modeling has been developed using NetLogo which is a multi-agent programmable modeling environment, and applied for a small area in Yangpyeong, Seoul. Geographic information on buildings and emergency shelters were loaded and used for agents to decide an optimal route to the nearest shelter. Agents were categorized into adults, children, seniors and the disabled based on the speed to evacuate. Evacuation patterns were assumed as follows: 1) Agents head for the nearest shelter. 2) If there are buildings on the way, they rotate until they find a way to the nearest shelter through buildings or the direction is against the shelter or against the direction which they headed for in the previous step. 3) Adults take care of a child within a certain radius and the adults accompanied with a child are slowed down. 4) All agents are retarded in a crowed place in proportion to the number of agents. The simulation results show that the GIS and agent-based modeling well represents the evacuation patterns of the agents assumed for this study. Once the evacuation patterns are provided, the GIS and agent-based modeling will be useful to plan evacuation routes and to create evacuation maps in vulnerable zones.
The Relationship between Job Stress and Alcohol-use Disorders among Firemen
Jo, Seon Deok ; Park, Jae Beom ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 133~140
DOI : 10.9798/KOSHAM.2012.12.1.133
Cross-sectional study was carried out on 456 firemen in Gunpo region in Suwon as the subjects in order to investigate the relationship between high and low risk job stress groups, and AUDIT among firemen. The level of job stress was measured by using KOSS-SF, PTSD by using IES-R-K and drinking level by using AUDIT-K to categorize the subjects into AUDIT group 85(23.7%) and normal group 274(76.3%). When the median value of job stress of all the working people of the country was used as the reference level, 124 subjects belonged to high risk group (34.5%) and 235 subjects to low risk group (65.5%). From the sociodemographic perspective, there was significant correlation with AUDIT in accordance with the age, smoking, educational and income levels. In job characteristic, work duration, type of work, work time and numbers of cases impact the increase in drinking. However, PTSD has not illustrated significant relevance with AUDIT. High level of association was illustrated between the job-stress and drinking level in the domains of interpersonal conflict, inadequate rewards and insufficient job control. Job stress was deemed to be an important factor in determining the drinking level with high level of importance in interpersonal conflict (or=11.089, 95% CI:4.985~24.669), inadequate rewards(or=3.598, 95% CI:1.732~7.472), and insufficient job control(or=2.232, 95% CI:1.199~4.156).
The Analysis of Smoke Characteristics for Wood Flour-High Density Polyethylene Composites
Shin, Baeg Woo ; Bang, Dae Suk ; Chung, Kook Sam ; Song, Young Ho ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 141~146
DOI : 10.9798/KOSHAM.2012.12.1.141
This paper is to analyze the smoke characteristics of wood flour-HDPE composites. The wood flour-HDPE composites were manufactured by modular co-rotating twin screw extruder. In order to analyze smoke characteristics, Cone calorimeter tests(by ISO 5660-2) and smoke density tests(by ASTM E 662) were performed. The specimens for these tests were differently made by adding flame retardants. The results of cone calorimeter test showed that adding flame retardants specimens are lower total smoke release, total smoke production than those of wood flour-HDPE composite. Also the results of smoke density test showed that adding flame retardants specimens are lower initial smoke data and maximum specific optical density than those of wood flour-HDPE composite. The most effective flame retardant is magnesium dihydroxide to decrease smoke characteristics.
Supporting Capacity of Shallow Foundation under Combined Loading Based on Numerical Modeling
Ahn, Jae Hun ; Lee, Han Min ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 147~152
DOI : 10.9798/KOSHAM.2012.12.1.147
Offshore foundation technology has been developed in parallel with the development of oil industry, and recently its experience has been applied to the design of wind turbine structures. The shallow foundation is one of the options for offshore foundations which undergo combined horizontal and vertical loads and moment due to wind and current. In this paper, the supporting capacity of a shallow foundation under combined loads is investigated based on finite element analyses. Two groups of combined loads, the ones which apply in a single plane and which do not, are considered. The difference in shapes of failure envelopes under different groups of combined loads is discussed. This paper also discusses the failure envelopes with different contact conditions of foundation and ground.
Analytical Studies for Design Parameters of the Pavement Applying the Light-Weight Concrete Subgrade Supported by Piles
Lee, Byung Sik ; Lee, Woon Jin ; Song, Yong Sun ; Lee, Kwan Ho ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 153~158
DOI : 10.9798/KOSHAM.2012.12.1.153
Mitigation of influence of settlements on road structures is the most important considerations in designing of coastal road on soft ground. Improvement methods of soft ground have been applied traditionally, even though embed potential problems of long construction period and high cost. Accordingly, an innovative alternative pavement system has been suggested and studied for field applications, where the light-weight concrete subgrade supported by piles is applied to reduce pavement settlements developed due to soft ground. In this paper, in order to design reasonably and apply effectively the pavement system to the field, a series of parametric study applying finite element analysis was conducted to examine the effects of design parameters, such as the length and space of piles, the thickness and shear strength of soft ground. As a result, it has been concluded that the use of a light weight pavement was very effective in reducing the settlement of pavement. Also, the results of investigation on influence of design parameters on settlements could be suggested as technical informations to be referred for the design of light-weight pavement systems applied on future coastal roads, e.g., estimating the adequate length and space of piles corresponding to the condition of soft ground.
Study to Evaluate an Application of the BREACH Model at Fill Dam
Song, Ju Il ; Won, Jin Young ; Rim, Chang Soo ; Yoon, Sei Eui ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 159~166
DOI : 10.9798/KOSHAM.2012.12.1.159
This study examined how the two models such as DAMBRK and BREACH that can calculate the breach outflow depending on time steps affect the simulation result. Furthermore, as a result of the examination, a resonable methodology was suggested to build up the emergency action plan (EAP). The DAMBRK and the BREACH models were used to calculate the breach outflow from the Mantaro dam, and the outflow hydrograph estimated by BREACH model was similar to the measured one. Dam crest wide was an important factor for peak flow time. In cases of An-dong dam and upper and lower Mu-ju pumped-storage dam, when the dam crest wide was not considered, the peak flow occurred early, and discharge decreased, so that flooded area decreased. To obtain the breach outflow hydrograph similar to BREACH model simulate, the DAMBRK model could be corrected by adjusting parameters; however, it still includes many uncertainties. Therefore, for fill dam, in order to estimate the hydrograph under the situation of the dam break, the BREACH model is more resonable. Using the hydrograph simulated by BREACH model as input for flood routing could give a higher accuracy than only using DAMBRK model.
Determination of Relationships for Manning Roughness Coefficient Using Hydraulic Engineering Field
Lee, Jong Seok ; Oh, Gi Eun ; Park, Young Joo ; Jung, Jae Hoon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 167~177
DOI : 10.9798/KOSHAM.2012.12.1.167
This study is determined to use with the hydraulic engineering field of relationships for Manning roughness coefficient by the regression analyzing the field measurements of flow resistance data which consist of the total 2,614 rivers for 1,875 and for 793 data in natural and vegetated rivers. The measured distribution of Manning roughness coefficients by the Box-Whisker Plots show the values which ranges from 0.004~0.151 for 179 sand, 0.008~0.250 for 992 gravel, 0.015~0.327 for 651 cobble, 0.023~0.444 for 53 boulder in natural rivers, and also from 0.015~0.250 for 281 grass, 0.016~0.250 for 150 shrubs, 0.018~0.310 for 308 trees in vegetated rivers, respectively. Significant trends are obtained between Manning roughness coefficients and flow discharge, friction slope and relative submergence. The regression equations for Manning roughness coefficients derived as the power law form with a function of the flow discharge and the friction slope, and the equations for dimensionless shear velocity developed as a relation of the relative submergence in natural and vegetated rivers. Relationships of these semi-empirical and Manning roughness coefficients in field measurements can be useful for hydraulic engineering practice.
The Optimal Spatial Analysis of Precipitation in the Region of Gangwon
Um, Myoung Jin ; Jeong, Chang Sam ; Lee, Tae Sam ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 179~192
DOI : 10.9798/KOSHAM.2012.12.1.179
In the current study, the regional frequency analysis was applied to estimate quantiles for the precipitation data of 75 stations in Gangwon province. The results of regional frequency analysis show that the generalized logistic distribution is the best fit for the Gangwon area. The four methods of spatial analysis were adopted with the quantile of regional frequency analysis as Thiessen, Inverse Distance Weighting (IDW), Barnes method, and Precipitation-elevation Regression on Independent Slopes Model (PRISM). Thiessen method presents the discontinuity in the quantiles of spatial distribution between observations. In the case of IDW method, the quantiles are concentrated around observations. Barnes method presents the averaging phenomena of quantiles and these phenomena become more serious when the effective radii become large. PRISM method considers the topographic variables rationally and maintains 85.18~89.89% of max-min ranges of quantiles. Accordingly, the IDW and Barnes methods are not applicable for the rainfall-runoff model. Therefore, we conclude that the PRISM in the current study is the best alternative among the four spatial analysis methods for estimating the spatial distribution in Gangwon area.
Assessment of Conceptual Rainfall Runoff Models for Regionalisation at Miho Catchment
Choi, Ho Hoon ; Lee, Hyo Sang ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 193~203
DOI : 10.9798/KOSHAM.2012.12.1.193
The risk of flood and drought have been increasing due to climate change. The major rivers catchments in Korea are relatively well maintained, however, most of mid-small sized ones, which are remained as ungauged, are still in difficulties in water resources management. Therefore, a reliable estimation of discharge is needed for flood risk management in mid-small sized catchment. This study is aimed to find the most suitable Rainfall-Runoff(RR) model for the regionalisation in upper Kemgang region. 9 RR models, which are combined form 3 Soil Moisture Accounting models and 3 Routing models in Rainfall-Runoff Modeling Toolkit(RRMT), are applied to 7 sub-catchments in Miho catchment. The performance of continuous simulation of these models is investigated with Monte-Carlo Analysis Toolkit(MCAT). The period of 2004~2007 and 2008~2009 are used for calibration and validation respectively. The Nash Surcliffe Efficiency(
=1-NSE) measures is used as objective function. The results show that CWI-2PMP(0.09-0.39 in
) and PDM-2PMP(0.16-0.37 in
) are promising models for further regionalisation research in Upper Kumgang region. The routing components (2PMP) in RR models shows that the fast response of catchments are dominant hydrological characteristics in upper Keumgang region. Further research will increase the number of catchments to draw a concrete conclusion.
Verification of the Design Force Estimation Method for the Steel-type Breakwater in the Real Sea
Kweon, Hyuck Min ; Kwon, Oh Kyun ; Han, Yu Sik ; Yoon, Kang Hun ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 205~215
DOI : 10.9798/KOSHAM.2012.12.1.205
The steel-type breakwater has the merits of structural simplicity and passing the long period wave for beach accretion. So, it has been expected to be a key tool for the strategic beach protection technology. The design methodology of the steel-type breakwater was published by Kweon et al.(2011), Kwon et al.(2011), Lee et al.(2011). For the analysis of the resistant friction load acting on the pile, Kweon et al. proposed the estimation method of the design up lift force acting on the dual horizontal plate. With a train of regular wave corresponding to the significant one, they integrated the distribution of the biggest pressure at each point. For the verification of the estimation method of the load on the pile, the study is carried out the experiment in a real sea state. Moreover, the construction procedure, the displacement, joint checking and removal possibility of the steel-type breakwater are discussed. The constructed breakwater has the horizontal wave energy dissipator of
) and pile diameter of 711 mm, thickness of 12 mm, length of 23.2 m. The construction took about 8 hours for 1 cell composed of 9 piles and 1 horizontal dual plate. There is a little vertical and horizontal displacement of pile attacked by the maximum wave height of 5.83 m. The removal of 1 cell took about 2 days. This study shows the merits of the easier design, faster construction and simpler removal of the steel-type breakwater. The structure could be estimated as a stable one because it has the horizontal dissipator on which acting a little compression and a little uplift force due to the perforated holes. Moreover, the easier removal could make it possible to manage the coastal line as depending on the conditions of erosion or accretion sand volume.
A Analysis Model for Urban Flooding Hazard Zone based on the SWMM Simulation Historical DB
Kim, Ki Uk ; Kim, Sang Dan ; Kim, Chang Soo ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 217~222
DOI : 10.9798/KOSHAM.2012.12.1.217
The main objective of this paper is to develop the model for flooding area decision including location, slope, elevation and depth of the flooding area and runoff drainage system thorough SWMM simulation DB and for the display model of the flooding areas. This model also provides the searching service to the historical flooding areas. ArcObject GIS engine and Oracle DBMS is used to model development, and the prototype system programmed with C# is applied to verify the model. The result of the model application analyzes flooding hazard areas of
with flooding depth of 0.08m. The six drainage systems is required improvement for discharge capacity. This research can be used the element technology of the disaster historical system for areas prone to floods.
An Application of Copulas-based Joint Drought Index for Determining Comprehensive Drought Conditions
Kim, Sang Dan ; Ryu, Jung Su ; Oh, Kuk Ryul ; Jeong, Sang Man ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 223~230
DOI : 10.9798/KOSHAM.2012.12.1.223
Current judgment for drought start and development status is based on drought indices which do not capture the jointly correlated effect of various variables related to drought correctly. To address this limitation, we tried to reflect such joint behavior for multiple variables related to drought by using copulas. Utilizing 60 stations of the whole county with 30 years observations(to 2010 from 1981) in Korea, the dependence structures of standardized precipitation indices with various window sizes from 1-to 12-month are constructed from empirical copulas. A joint drought index (JDI) is defined by using the distribution function of copulas. As a result from applying to several historical drought events, the proposed JDI is expected to describe well the overall drought status.
Analysis of Long-Term Trends in Lake Water Quality Observations
Kim, Eung Seok ; Yoon, Jo Hee ; Lee, Jae Woon ; Choi, Hyun Il ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 1, 2012, Pages 231~238
DOI : 10.9798/KOSHAM.2012.12.1.231
Most lakes are more than 50 years old in Korea, and the vulnerability to water pollution in lake areas has increased due to the increase of inflow pollutant loads caused by human activities. This study has investigated water quality characteristics for the six lakes in Geum River basin through an analysis of long-term water quality trends. It is observed that most results from the six lakes show unstable periodicities in long-term water quality observations and all lakes have low water quality with a level IV and above. Water quality improvement is required for the four lakes except Tapjeong Lake and Boryeong Lake, and water quality management plans are urgently needed especially for Sapgyo Lake where the water quality has been continuously deteriorating. On the other hand, Boryeong Lake well managed for water control and use in multi-purpose dam operations keeps water quality high compared with other lakes under study. It is expected that the results in this study can make a contribution to the water quality management plan incorporating long-term seasonal water quality changes.