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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
Evaluation on Vertical Load Carrying Capacity of Steel Structure by Limit Analysis
Kim, Jung Hwan ; Choi, Jae Hyouk ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 1~8
DOI : 10.9798/KOSHAM.2012.12.4.001
Recently some building structures have collapsed because of losses of vertical load carrying capacity resulting from accidental events. Today, even if buildings are partially damaged by accidental events that have not been foreseen, a specific design technique, by which the damage does not cause fatal gravitational collapse or progressive collapse, and a technique to improvement load carrying capacities efficiently are required. Consequently, in this paper, examined structures Load Carrying Capacity about Vertical Load which through Linear Programming based on Low-bound Theorem of Limit Analysis. We also considered a change progress of load carrying capacity according to circumstances about installation of brace and belt truss widely used in horizontal displacement control of building and then, analyzed an effect from loss of number generated by accidentally externer force which has an effect on load carrying capacity of building.
The Analytical Study on Seismic Performance Evaluation for Reinforcd Columns of Underground Tunnel
Kim, Jinsup ; Kwon, Minho ; Jung, Wooyoung ; Kim, Kihong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 9~15
DOI : 10.9798/KOSHAM.2012.12.4.009
Due to the recent earthquakes, more interests have been focused on the retrofitting of existing structures. Especially, FRP composite material is actively used in the seismic resting design. Usually the destruction and damage of the under ground tunnel causes much impact to the social system since it contains a lot of life lines including subway, power and water lines, and so on. However, the retrofitting is more difficult due to the spacial limitation. The numerical simulation of underground tunnel using FE analysis can provide some guideline for the retrofitting rather than the experimental approach which is not simple and very expensive. In this study, the underground tunnel is evaluated through the nonlinear push over analysis and nonlinear dynamic analysis with modeling of soild as infinite elements.
Study of Interaction on Earthquake Response of Adjacent Buildings Founded at Different Depths
Kim, Dong Woo ; Kim, Sung Chil ; Huh, Young ; Kim, Yong Min ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 17~23
DOI : 10.9798/KOSHAM.2012.12.4.017
The aim of this paper is to study the interaction between adjacent buildings with different foundation levels under earthquake loading conditions. Buildings and soil are represented by two different models. In the first case the building itself is modeled with standard frame element, whereas the soil behavior is stimulated by a special grid model. In the second case, the building and soil are represented by plane stress or plane strain elements. The modulus of elasticity of the ground is varied. Just like the modification of the modulus of elasticity the varying relations of inertia have a strong influence on the section forces within the buildings. The analysis is carried out using numerical program which has been developed based on the axisymmetric fein element method in corporation of grob element for soil region and wave input technique transit boundary condition. Interaction of the proposed method is demonstrated in numerical examples.
Effect of Crossbeam on Dynamic Characteristic and Safety of PSC-I Railway Bridge
Yun, Ji Hong ; Choi, Kwon Young ; Kwon, Ku Sung ; Chung, Won Seok ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 25~30
DOI : 10.9798/KOSHAM.2012.12.4.025
Railway bridges are highly susceptible to resonance due to the equidistant axle load with constant speed of train. Thus, it is inevitable verify dynamic characteristics and quantities against dynamic guidelines. Recently, PSC-I composite bridge are being used actively due to economic advantages such as 20~30 m span bridge at home and abroad. This study investigate the dynamic properties and safety of PSC-I railway bridge having length 25 m in different crossbeam. Numerical analysis is performed time series analysis by mode superposition using calculated natural vibration frequency and mode after carry out a free vibration analysis and extract modal parameter to higher modes. Consequently, the result met baseline satisfactorily in every case include virtical displacement, acceleration and distort. The result of this study shows there is no problem with safety of dynamic that consider maximum space of crossbeam, whereupon we expected as a reference for design railway bridges.
An Experimental Study on the Seismic Performance of FRP Composite Pier
Lee, Young Ho ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 31~37
DOI : 10.9798/KOSHAM.2012.12.4.031
This paper presents an experimental investigation of seismic performance for two types of concrete filled FRP column using such as concept. The first type is the CFFT with cast-in-place concrete filled within a FRP tube playing the role of form and lateral confinement. The second type is the precast CFFT column using FRP as lateral confinement. Both methods provide improved compressive strength according to the increase of transverse reinforcement and prevent spalling even after failure of the filling concrete confined by FRP, which allows advantageously slow and gradual loss of bearing capacity. Four scale-down specimens were conducted by quasi-static cyclic loading test. The capacities of ductility for cyclic loading was evaluated and the damping ratio, the stiffness reduction and energy dissipation of each test specimen were compared.
Behavior of Continuously Reinforced Concrete Track Subjected to Temperature Changes
Kim, Jin Il ; Cho, Young Kyo ; Kim, Jeong Il ; Kim, Seong-Min ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 39~44
DOI : 10.9798/KOSHAM.2012.12.4.039
This study was conducted to investigate the behavior such as stress and crack width of continuously reinforced concrete track (CRCT) subjected to temperature changes. Three-dimensional finite element analysis models of CRCT were developed in this study. The effect of the existence of sleepers on the stress distribution in CRCT was investigated using the models. The effects of changes in the material properties such as elastic modulus, thermal expansion coefficient, and Poisson`s ratio and in the crack spacing on the CRCT behavior were also analyzed. The analysis results showed that the CRCT model without considering the existence of sleepers was more appropriate to the prediction of cracking. The sensitivity analysis results showed that the thermal expansion coefficient affected the CRCT behavior the most and followed by elastic modulus and Poisson`s ratio. In addition, there were slight differences in the effects of material properties on the CRCT behavior depending on the crack spacing.
The Analysis of Behavior of Steel Box-truss Hybrid Curved Bridge
Jang, Min Seo ; Kim, Jeong Hun ; Kim, Jongmin ; Kang, Young Jong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 45~50
DOI : 10.9798/KOSHAM.2012.12.4.045
Steel Box-Truss Hybrid bridge consisted with steel box type in positive moment that is allowed to resist with low depth and truss type in negative moment not only has restriction of delivery but has to use high depth is new type bridge. This can be used as 80m~150m long span bridge and is economical structural type. But safety of truss type is concerned because of torsion that occurs when Steel Box-Truss Hybrid bridge applies a curved bridge. Therefore, it is necessary to analyse and evaluate straight and curved bridge for commercialization of Steel Box-Truss Hybrid bridge. In this study, structural analysis of Steel Box-Truss hybrid curved bridge with various curvature is performed and compared with member force and displacement of Steel Box-Truss Hybrid straight bridge. Also the applicable limited curvature of Steel Box-Truss Bridge form is proposed.
Pipe Failure Simulations with Individual Pipe Failure Probability for Estimating the Reliability of Water Distribution Systems
Jun, Hwandon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 51~57
DOI : 10.9798/KOSHAM.2012.12.4.051
Estimation of the reliability of a Water Distribution System(WDS) is important to understand the current operating condition of the system. Although, there is no widely accepted method to estimate the reliability of a WDS, the Jun`s model which is based on the pipe failure simulation and its impact can be efficiently adopted for the purpose by the water utility. In the model, however, it is assumed that the pipe failure probability of each pipe is even and this assumption may bring unrealistic estimation of the reliability of a WDS since with this assumption, the actual pipe failure characteristics occurred in the WDS cannot be simulated. For this reason, in this study, we suggest a modified method of the Jun`s model to consider the individual pipe`s failure probability. The regression equation which is based on diameter and length of the pipe is used to estimate the failure probability of the individual pipe and then, the pipe failure simulation is performed. The suggested model is applied to a real WDS to compare the results of the two models. Comparing them, it is concluded that the failure probability of the individual pipe should be considered to estimate the accurate reliability of a WDS when it is estimated by the pipe failure simulation.
Preventive Measures Assessment to Prevent Flooding Complex Underground Space through Hydraulic Model Experiment
Shin, Dong Soo ; Park, Jae Beom ; Shon, Tae Seok ; Jo, Deok Jun ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 59~65
DOI : 10.9798/KOSHAM.2012.12.4.059
Variation of the urban functions on complex underground space development and increasing demand, and due to heavy rainfall caused by climate changing, flooding in complex underground space into a situation where the possibility of more increases to minimize flood damage in underground space for various requires measure to prevent flooding. In order to establish the optimal protect against flooding, a study uses the hydraulic and numerical model experiments, and each inundation measures the flow characteristics in an underground space required for the research and studies in a Korea, however, it has been little. In this study, the risk of flooding underground space in the presence of EPA SWMM model basin runoff analysis to build up complex underground space and the results were applied at a flow rate on flooding. Not only the study calculated the experimental value every scenario through checking whether there is storage facility or not, the installation of the sand bag and barrier wall by making the underground space of special building which mainly affected by the quantity of runoff in the object basin into hydraulic model, but also tried to analyze the flooding tendency of the underground by figuring out water level change of the Inundation.
A Model for Evaluation of Debris Flow Risk in a Watershed
Ryu, Han Joong ; Shin, Jong Hwan ; Seo, Hung Seok ; Kim, Gi Hong ; Lee, Seung Woo ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 67~76
DOI : 10.9798/KOSHAM.2012.12.4.067
In general, landslides of mountain areas have been occurred by typhoon and severe rain storm in Korea. The multiple landslides caused by heavy rain may lead to debris flow which is very rapid downslope movement of debris of a high water content along stream channels. Generally, a debris flow causes larger and severe damage. than a landslide. To protect and reduce the damage of debris flow, a reliable tool to predict potential damage area by drbris flow is needed. Since the water and moveable soils by landslide flow from high elevation to low elevation with additional erosion through the stream of valley, the magnitude of debris can subsequently amplified. Therefore any structures and people in the path of debris flow lies in great risk. Due to the chacteristics of debris flow which is delivered quite a long distance from the location of initiation (hundread meters - kilometers), the risk analysis of debris flow should consider larger area compared with landslide analysis and analysis unit need to be determined based a watershed. In this study, an anlysis tool for the evaluation of debris flow risk in a watershed incorperated with GIS system is proposed. The essence of system is a model to predict the risk of debris flow for any given location. The model is developed based on the statistical analysis of forty eight debris flow cases, which obtained from: field surveys, disaster reports on national roads of korea, and digital maps of the debris flow area. Each set of data in the database includes debris flow size, rainfall information, bedrock types, and run out distance of the debris. The comparison between predicted risk and actual occurrence of the debris flow hazard for forty eight site, showed accuracy of seventy seven percent based on accuracy-classification.
A Study on the Improvement of Stability Checklist by Analyzing the Evaluation Element For Steep Slopes
Song, Young-Karb ; Park, Dugkeun ; Son, Young-Jin ; Kim, Tai-Hoon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 77~84
DOI : 10.9798/KOSHAM.2012.12.4.077
There are stability checklists for steep slopes in order to evaluate their function and performance especially when they are initiated to move. It is, however, difficult to ensure the reliability of the checklist because of the diversity of institutions which use the checklist, the subjectivity of observer`s opinion, and the difference of scores in items even though they indicate same characteristics. In this study, therefore, an improved checklist and methodology is proposed, which is based on the modification of five representative steep slope stability checklists from different institutions. This may help for non-professionals to determine overall stability of steep slopes. Also, a verification is performed by applying it to identified collapsed steep slopes in order to get a reliability of the proposed checklist compared to existing checklists.
Slope Stability Characteristic of Unsaturated Weathered Granite Soil in Inje considering Antecedent Rainfall
Lee, Ji Sung ; Song, Young-Karb ; Kim, Yun Tae ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 85~92
DOI : 10.9798/KOSHAM.2012.12.4.085
Unsaturated geotechnical properties and other factors(rainfall characteristic, geomorphology, etc) have to be considered in order to evaluate the stability of real slope. Even though antecedent rainfall is also an important factor on the slope stability, it is rarely considered in analysis of slope stability. In this paper slope stability analysis for unsaturated weathered granite soil in Inje was conducted considering antecedent rainfall. Effect of antecedent rainfall was considered in analysis by using initial matric suction, which was induced from field measurement. Unsaturated geotechnical properties(soil-water characteristic curve, unsaturated conductivity, unsaturated shear strength) of weathered granite soil in Inje were also investigated. Effects of antecedent rainfall on variation of factor of safety(FS) of slope, failure time and cumulative rainfall were evaluated. For a slope with high initial matric suction, FS slowly decreased and failure time delayed than a slope with low initial matric suction. Numerical analysis also indicated that a slope with wetting SWCC more rapidly approached to failure than a slope with drying SWCC.
Compression Behaviors of Artificially Cemented Composite Geo-Materials
Ahn, Jaehun ; Kim, Yusuk ; Kim, Yun-Tae ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 93~99
DOI : 10.9798/KOSHAM.2012.12.4.093
The lightweight soil is an artificially treated soil with air form to reduce the unit weight - therefore making a good backfill material - but is often cement-treated to ensure enough strength. This artificially treated soil has been evolved to be more environment-friendly by using the dredged soft soil and mixing with the bottom ash therefore taking care of by-products of offshore construction and coal production. One of the unique characteristic of this family of Composite Geo-Material(CGM) is that they show drastic strain softening in their stress-strain curves, whose constitutive relations are not properly modeled by casual constitutive models, such as conventional hyperbolic or modified cam-clay model. A new set of modified hyperbolic equations is developed to model CGM materials, and its model parameters are presented based on the results of laboratory tests.
Implementing FDWS(Fog Detect & Warning System) with LED Module Structure : Estimation of Safety Effects
Lee, Suk-Ki ; Moon, Jae-Pil ; Jung, Jun-Hwa ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 101~106
DOI : 10.9798/KOSHAM.2012.12.4.101
Although drivers use various sensory channels to control and navigate their vehicles, they acquire most of all driving-related information visually. In fog, no matter what visual acuity is, the visual channel is useless due to the induced poor visibility. Drivers react differently to the adverse weather, resulting in high speed variation. That is why it has the high fatal rate during foggy conditions. Then, it is imperative to provide drivers positive guidance in fog. In this study, the Fog Detect and Warning System (FDWS), being called as the fog lighthouse, was conceived to inform drivers of safety speeds and distances between each vehicle. FDWS includes visibility meters, light bars, and vehicle detectors. The visibility meters calculate sight distances when fog occurs and the estimated sight distances inform drivers through the light bars which are installed at every 30m intervals. The light bars which display red warning lights inform a following vehicle of the position of the leading vehicle to keep the safety distance between the two vehicles. Since the main lights with the high-bright LED (Light Emitting Diode) have high visibilities, drivers can easily recognize far away. Also microwave sensors together with the light bars are installed to detect the presence of vehicles at every 30m intervals. The aim of this paper was to evaluate the effectiveness of the fog system on driver behavior and consciousness. As a pilot study, FDWS was implemented on a 1km section of National Highway No. 37 with a divided four-lane, rural highway. The analysis of the driver behavior was based on mean speed with standard deviation, and a questionnaire survey was conducted to estimate the driver consciousness. The results indicates that FDWS significantly led to an about 3kph (for daytime) and 10kph (for nighttime) reduction in mean speed compared to the system turned off. Also the consciousness survey shows that FDWS was useful helping drivers guide safely in fog.
Analysis of Fire Risk with Building Use Type Using Statistical Data
Shin, Jin Dong ; Jeong, Seong Hui ; Kim, Mi Sun ; Kim, Hyun Ju ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 107~114
DOI : 10.9798/KOSHAM.2012.12.4.107
This study is analyzed fire risk quantitatively based on building use type using statistical data in order to get information applicable to the establishment of fire prevention policies. For statistical data, 4 years` data (2007-2010) from the National Fire Data System and the building classification from the Building Act were used. Fire risk was rated through both absolute evaluation using the range of the fire risk index from the Society of Fire Protection Engineers (SFPE) and relative evaluation using the risk matrix. According to the results, facilities rated as "A," has high risk of fire which fire may take place several times during the life of building. The "A" rated buildings included religious facilities, markets, office buildings, factories, warehouses, automobile facilities, animal and plant facilities, charnel and hygiene facilities, military and correctional facilities, and power generation facilities. When the risk matrix was applied to analysis the fire risk to the facilities, lodging facilities, power generation facilities, religious facilities, charnel and hygiene facilities, markets, military and correctional facilities, warehouses, animal and plant facilities and factories turned out to be have over "IV" which has the higher fire risk than other facilities. This paper finally suggested how to apply these results to government policies on facilities with fire risk.
Study on Installation of Underground Storage Facilities for Reducing the Flood Damage
Choi, Hyun Gu ; Han, Kun Yeun ; Yi, Jae Eung ; Cho, Wan Hee ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 115~123
DOI : 10.9798/KOSHAM.2012.12.4.115
The flood damage in urban area has been caused by lack of capacity of drainage facility, insufficient water retention, reservoir & regulation pond, and lack of capacity for drainage pump station etc. In general, inundation area used to be in small scale but in case of urban area, due to high density of assets, it has been experiencing high density of damage in terms of per unit area. Thus it is necessary to have accurate estimation of inundation area by taking into account poor drainage system in connection with heavy rainfall. In this study, runoff simulation during heavy rainfall was carried out in the area of Bisan drainage basin and the effect of reduction of inundation by the installation of underground storage facilities was analyzed as a method to reduce the damage of inundation. To examine existing drainage capacity in time of flash flood as well as abnormal heavy rainfall and to analyze mitigation effect of inundation damage upon installation of underground storage facilities, the rainfall runoff analysis was carried out on the probable rainfall of 10, 20, 50 and 100 year frequency which exceed facility design frequency.
Effect of Green Roof to Reduce the Electrical Fire
Park, Seon Yeong ; Oh, Ja Hun ; Park, Hyo Seok ; Lee, Ja Wook ; Moon, Jong Wook ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 125~131
DOI : 10.9798/KOSHAM.2012.12.4.125
As cities of modern society is developed into high-density areas, they are confronted with several problems. Those problems could be divided into two ways. One is above-average temperatures caused by pollution and the other is the energy depletion. That is the reality we are confronted with. Heat Island, one of the phenomenons of above-average temperatures in cities by reducing greenbelt, occurs and the amount of energy used for air conditioning and heating also increases. In this study, we confirmed the correlation between energy saving effects and frequency of electrical fire as a result of the study on how energy saving effects depending on the temperature change of buildings influence the electrical fire, one of the causes of fire.
Flow Coefficients of Doorway Flow Field in Two-room Building Fires
Ju, Hyeon Don ; Kim, Hyun Hyi ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 133~142
DOI : 10.9798/KOSHAM.2012.12.4.133
In the case of a fire of two-room`s enclosure, the inflow and outflow mass rates through the doorway located between a burn room and an adjacent room have been researched. The objective of this study are to calculate the flow rates through the doorway of the burn room, to study the inflow and outflow coefficients of the doorway, and accurately to predict the neutral-plane height from the floor of the room in the stratified fire cases of the two-room`s enclosure. The inflow and outflow mass rates are analyzed by FDS developed by the National Institute of Standard and Technology, USA. The analyzed results by FDS are compared with the experimental results performed by Nakaya et al. By our study it is known that the flow coefficients vary according to fire size and opening configuration and the mean values of the inflow and outflow coefficients are 0.8 and 1.0 respectively.
A Study on the Difficulty of Door Opening on Very High Floors Due to Stack Effect in Cold Season
Kim, Jinsoo ; Lee, Eui-Pyeong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 143~148
DOI : 10.9798/KOSHAM.2012.12.4.143
Super high-rise residential buildings are more subject to stack effect through the door gaps of elevators in cold season due to the more number of elevators than in low buildings, and to reduce those effects, air tightness of skin is essential, but that is released in case of fire because the exit doors on the 1st floor are to be fully open for egress of people and entrance of fire brigades. This paper offers the calculation model to estimate the inconvenience and difficulty of door usage in normal and emergency time, the method to solve the difficulty, and the validity of the method with simulation.
A Numerical Study on the Attenuation of Fire Alarm Sound
Roh, HyeongKi ; Im, Jungsoon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 149~154
DOI : 10.9798/KOSHAM.2012.12.4.149
This study theoretically examined domestic and overseas sound standard of fire alarm and the sounder was installed in accordance with the criteria specified in the `fire safety code`, and the adequacy of sound level with which fire alarm sound can be conveyed to residents were verified by numerical analysis of the sound level of the farthest location from the sounder. The sound level of fire alarm analyzed with the criteria specified in the fire safety standard about the place which is located at the farthest distance from sounder was appeared to be 36 dBA, 59 dBA and didn`t satisfied from 65 dBA specified in the UK standard in evaluation model. The sound of fire alarm could accurately be conveyed when a separate sounder was installed at a room which was partitioned in order to convey the sound of fire alarm to the resident of building. In performance-based fire protection design, if sound attenuation was calculated for application, it was analyzed that damage of human life could be reduced with rapid evacuation through accurate reception of the fire alarm sound on the part of resident on the fire. Based on the result of this study, wider range of studies for the sound attenuation of fire alarm sounder would be required, and legislation regarding the spacing of the fire alarm sounder need to be revised and supplemented.
An Experimental Study on Establishment of Classification System of Fire Resistance Wall Structure
Choi, Dongho ; Kim, Daehoi ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 155~161
DOI : 10.9798/KOSHAM.2012.12.4.155
To minimize the damages under fire conditions in buildings, the main structural members of buildings shall be fire-resistance-rated structural members. The relevant authority specifies the prescriptive fire-resistance-rated structural members which have 3-hour fire rating equally without any classification in building laws at present unlike foreign countries. But, these prescriptive fire-resistance-rated structural members don`t properly reflect the recent construction materials and the technical development of methods of construction as a long time has passed. Consequently, it is needed to specify so that the fire resistance performance of structural members can be departmentalized according to the detail design and applied part and to improve the relevant system based on the test materials of fire-resistance-rated structural members economically and efficiently. This study was intended to give the fundamental materials that prescriptive fire-resistance-rated walls are departmentalized as each structure by evaluating the fire resistance performance of prescriptive fire-resistance-rated walls.
An Experimental Study on Establishment of Classification System of Fire Resistance Roof Structure
Choi, Dongho ; Seo, Heewon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 163~168
DOI : 10.9798/KOSHAM.2012.12.4.163
To minimize the damages under fire conditions in buildings, the main structural members of buildings shall be fire-resistance-rated structural members. For the roof which is one of the main structural members, the relevant authority only specifies the prescriptive fire-resistance-rated roof frames whose fire resistance performance has been checked by the relevant authority in building laws at present. But, these prescriptive fire-resistance-rated roof frames don`t properly reflect the recent construction materials and the technical development of methods of construction as a long time has passed. Consequently, it is needed to reset the fire resistance performance through the performance evaluation for the roof constructions specified as the present main structural member and the prescriptive fire-resistance-rated construction. This study was intended to give the fundamental materials that prescriptive fire-resistance-rated roofs are departmentalized as each structure by evaluating the fire resistance performance of the roof construction specified as the present main structural member and the prescriptive fire-resistance-rated construction.
The Quantification of Disaster Impact of Extreme Rainfall under Climate Change in Korea
Jang, Dae Won ; Kim, Byung Sik ; Kim, Ju Hwan ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 169~178
DOI : 10.9798/KOSHAM.2012.12.4.169
Recently, the disaster has been increasing due to climate change in the urban. The type of disaster are appeared very complex as urban flooding, river flooding, landslide, debris flow. For this reason, there is a growing concern about extreme rainfall and locality heavy rainfall caused by climate change. Limited resources and space, disaster decision is very important. Thus, for accurate disaster decision-making, we have to assess the impact of disasters due to climate change. In this study, we simulated rainfall in the future(2001-2100) using by a set of SRES A2 Climate change scenarios derived by RegCM3 RCM. Then we assess EVI(Extreme Volatility Index), HRI(Human Risk Index), DII(Disaster Impact Index) for evaluate the impact of extreme rainfall caused by climatic change on disaster risk. EVI was higher in the Gyeongsang-do and Jeolla-do region, HRI was higher in the 7-Megacity(Seoul, Busan, Incheon, Gwangju, Daegu, Daejeon, Ulsan) and Gyeonggi-Do region, and DII was higher in the Seohaean and the region between Gyeongsang-do and Jeolla-do.
An Evaluation of Inundation Risk of Urban Watershed Using Data Envelopment Analysis
Kim, Jaehee ; Park, Moojong ; Lee, Jungho ; Jun, Hwandon ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 179~186
DOI : 10.9798/KOSHAM.2012.12.4.179
In order to prevent the flood damage of urban watersheds, it is important to anticipate the relative inundation risk of urban watersheds and to perform inundation damage mitigation projects. Therefore, we propose a methodology for evaluation of the relative inundation risk of urban watersheds to determine the project priority for each watershed. For this purpose, we suggest to use cross efficiency of Data Envelopment Analysis (DEA), which can consider the probability of inundation occurrence and the inundation damage simultaneously. In this method, the average slope, density of conduit, elevation, and the sediment yield per unit area of subcatchment were used as input parameters representing the probability of inundation occurrence while population of the subcatchment as an output representing the inundation damage. After the suggested method is applied to GunJan Basin, Seoul, it is shown that the DEA model can estimate the relative inundation risk of each watershed even though it does not require decision makers to asses the weight on individual input and output parameter, which is required in the other multi-criteria decision making models such as the Analytic Hierarchy Process and PROMETHEE. The estimated relative inundation risk of each watershed can be used to determine the project priority for each watershed.
Parameter Estimation of the Neyman-Scott Rectangular Pulse Model Using a Differential Evolution Method
Kim, Gwangseob ; Cho, Hyungon ; Yi, Jaeeung ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 187~194
DOI : 10.9798/KOSHAM.2012.12.4.187
The NSRPM(Neyman-Scott Rectangular Pulse Model), a stochastic rainfall generation model using clustered point process theory, is widely used in hydrology since it is able to reflect the cluster characteristics of rainfall events but the RPM(Rectangular Pulse Model) is not able to handle that. DFP(Davidon-Flectcher-Powell) and GA(Genetic Algorithm) are generally used to estimate 5 model parameters of the NSRPM. However DFP is sensitive to initial value and has tendency to get not global solution but local minimization. GA has an advantage of optimizing without Hessian matrix, but it needs relatively long computing time. In this study, a DE(Differential Evolution) method applied in model parameter estimation in order to overcome those drawbacks. The rainfall model parameters during the summer season (June-August) at Seoul, Pusan, Daegu, Mokpo, Gangrung, which have more than 30 year long hourly precipitation data, were estimated using hourly rainfall data from 1961 to 2011. Results were compared to those using DFP and GA. The performance of the DE method was evaluated using test statistics and demonstrated better performance in preserving physical and statistical properties of observed rainfall data.
A Reliability Evaluation Method of Storm Sewer Networks for Excessive Rainfall Events
Lee, Jung Ho ; Park, Moo Jong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 195~201
DOI : 10.9798/KOSHAM.2012.12.4.195
One of the researches about the reliability of storm sewer network defined the sewer system failure as the overflow occurrence for the rainfall events and suggested the reliability evaluation method of storm sewer network, RSDMM(Reliability of Sewer system using DMM). In this study, 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) to estimate the distance between the parameters while the units and dimensions of each parameter are different. But, the frequency boundary of applied rainfall events was not clear although the reliability results can be different when the boundary of rainfall event`s frequency is different. That is, the RSDMM is estimated as the average of overflows for each excessive rainfall event although the overflow occurrences are different according to applied rainfall frequencies. Therefore, to solve these problems and improve the RSDMM, in this study, the frequency boundary of applied rainfall events was defined clearly and the scale control between the number of overflow nodes and overflow volume was organized. Then, the reliability of sewer network is estimated as the quantitative evaluation and this new suggested method improved the RSDMM of Lee`s study.
Determing the Monitoring Point for Efficient Operation of Urban Drainage System
Ryu, Seung Hyun ; Park, Moo Jong ; Lee, Jung Ho ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 203~207
DOI : 10.9798/KOSHAM.2012.12.4.203
As the urbanization proceeds, the extent of impermeability has expanded due to the increase of land use changes and pavement percentage of the road. These facts have aggravated the danger of inundation such as the increase of urban efflux and the decrease in time of reaching permissible range. To handle the increasing amount of inundation, numbers of retarding basins and drainage pump stations are already constructed or under contemplation in the urban areas. Consequently, due to the fact that the damage caused by the inundation might fluctuate according to the technique of drainage pump operation, the importance of appropriate management in detention storage and drainage pump system has aroused, despite of the identical constructional condition of the retarding basins. However, this may work effectively when the efflux from the upper stream is predicted and the pump is activated beforehand. Therefore, for more effective management of drainage pump stations, the following research provides the method of selecting an adequate monitoring spot in the sewer system for the urban basins. Utilizing the entropy methods and linear regressions, the model provided below suggests a method of selecting monitoring spots considering the efflux of each basins and the concentration time to the outlet.
Natural River Flow Characteristics Using Chiu Velocity Distribution
Park, Minkyu ; Uhm, Changsub ; Song, Youngseok ; Park, Moojong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 209~214
DOI : 10.9798/KOSHAM.2012.12.4.209
The entropy parameter of Chiu velocity distribution was examined with the natural river flow characteristics. The previous reserchs focused on maximum point velocity estimation in order to improve the application of Chiu velocity distribution in natural river. However, the improvement of maximum point velocity observation does not ensured more accurate discharge estimation. This study reviewed the variability of the entropy parameter of Chiu equation. The entropy parameter has the relationship with water surface slope as a hydraulic characteristic factor. The decrease of water surface slope due to backwater effect showed the decrease of entropy parameter by experiments.
Development of a Simple Distributed Hydrologic Model for Determining Optimal Installation location and Quantifying Efficiency of LID Devices for Reducing Non-point Sources
Lee, Jeonghoon ; Cho, Seon Ju ; Kim, Jin Kwan ; Seo, Seongcheol ; Kim, Sangdan ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 215~223
DOI : 10.9798/KOSHAM.2012.12.4.215
In this paper a simple distributed hydrologic model is proposed to determine optimal installation location of LID devices and to quantify their non-point sources reduction efficiency in urban drainage catchment. The proposed model is applied to simulate surface runoff and non-point sources loading on urban drainage based on square cells. In the model, rainfall events occurring at each cell are transformed into surface runoff events by NRCS-CN technique, and non-point sources pollutants which have been built-up at dry period are discharged at wet period by washed-off process. Since the model can represent the drainage flow path explicitly when the overland flow is occurred and moved into the next lower cell, it is possible to look at the effects of the LID facilities positioning as well as the non-point sources reducing efficiency of such facilities.
Effect of initial pH Removal of Dichloroacetonitrile in Photocatalytic Ozonation by Using Compound Parabolic Concentrator Modules
Shin, Donghoon ; Na, Seungmin ; Cai, Jinhua ; Khim, Jeehyeong ;
Journal of Korean Society of Hazard Mitigation, volume 12, issue 4, 2012, Pages 225~231
DOI : 10.9798/KOSHAM.2012.12.4.225
In this study, we investigated to reaction rate of dichloroacetonitrile(DCAN) in each pH(3, 6.5, 10) using heterogeneous photocatalytic ozonation in order to determine optimal pH in photocatalytic ozonation (solar/
) process. The results, showed that DCAN was removed at pH of 3, 6.5, and 10 within 4h, and that the corresponding removal rates were 43.8, 91.1, 98.2%, respectively, in the solar/
process. The highest reaction rate was observed at pH 10. These results could be attributed to the self-decomposition of DCAN and the change in the mechanism of the ozone process. Besides, pH 6.5 also achieved a high degradation rate(91.1%) which is due to DCAN adsorbed onto the catalyst surface and reacted with radicals(
) generated by the reaction between ozone and electron(
) released from the conduction band of catalyst. The lowest degradation rate was observed at pH 3 due to absence of adsorption and no change in ozone reaction mechanisms.