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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 11, Issue 6 - Dec 2011
Volume 11, Issue 5 - Oct 2011
Volume 11, Issue 4 - Aug 2011
Volume 11, Issue 3 - Jun 2011
Volume 11, Issue 2 - Apr 2011
Volume 11, Issue 1 - Feb 2011
Selecting the target year
Study on the Resident`s Needs and System for Crime Prevention in Studio Type House
Hwang, Sung-Eun ; Park, Gyu-Tae ; Kim, Gwang-Hee ; Kim, Jin-Wook ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 1~8
DOI : 10.9798/KOSHAM.2011.11.6.001
Recently, the demand of house, which are one or two person living, is continually increased, the government implemented the policy of housing for the urban lifestyle to solve the housing shortage for one or two person house. But small-size housing such as studio type house have a few problems, which are confined space and noise etc., as mentioned previous research. Also, the crime related to an apartment house takes up one-third percent of whole crime of theft. Therefore, in this study, prospective resident`s needs and actual conditions are investigated by survey and fact-revealing in Seoul. The questionnaire-survey is conducted among visitors at model house of studio type house, and this survey is revealed that it is necessary to specialize in the specific space by ages, and that prospective resident`s take an interest in not only characteristics of space of house unit but also community facilities of residential building. Also, the fact-revealing implemented at five housing for the urban lifestyle, and result signifies the lack of security system such as absence of CCTV and guard etc.
The Experiment on the Capacity of Web-opening Steel Beams according to the Width-thickness Ratio
Lee, Yong-Jae ; Oh, Myoung-Ho ; Kim, Yong-Seok ; Kim, Sang-Dae ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 9~16
DOI : 10.9798/KOSHAM.2011.11.6.009
Web openings can be used to pass utilities through beams and to minimize story height. Decreasing building height reduces both the exterior surface and the interior volume of a building, which lowers operational and maintenance cost, as well as construction cost. Recently, using composite structures and PEBS(Pre-Engineered Building System) has steadily increased. Sometimes it requires non-compact section for web to reduce steel usage. According AISC Design Guide, the web opening should be only provided in the compact section. In this study, the changes in buckling load, yielding strength, and the deformation of specimens were evaluated experimentally for the non-compact section steel beam.
The Evaluation of Bearing Capacity of Glass Fibeer-Steel Composite Plate by Using High-tension Bolt
Seo, Hyun-Sik ; Ryu, Jae-Ho ; Ju, Young-Kyu ; Kim, Sang-Dae ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 17~23
DOI : 10.9798/KOSHAM.2011.11.6.017
Recently, FRP(Fiber Reinforced Plastics) is being widely used as a reinforcement material. GSP(Glass Fiber-Steel Composite Plate) is a sort of FRP to improve ductility of GFRP(Glass Fiber-Reinforced Plastics) installing steel plate between top and bottom GFRP Plates. Due to very high strength of GSP comparing to the weight of material, applying of this material is increasing for the building structures. As for the attaching of GSP to the structures, epoxy has been generally used. In this case, however, the quality of epoxy does not remain consistently, and it causes long period of work by hardening epoxy. In this study, to increase workability of GSP, the bearing tests of GSP were performed for applying of building structures with high-tension bolt. And the design equation for bearing capacity could be derived by performing the bearing tests.
Seismic Performance of Reinforced Concrete Beam-to-Column Joints Strengthened with Recycled Fibres from Fiber-Reinforced Plastics
Park, Jong-Won ; Paek, Joo-Hyun ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 25~30
DOI : 10.9798/KOSHAM.2011.11.6.025
Increase of waste FRP(fiber reinforced plastics) has caused environmental problems. Recently, the technology of making concrete-reinforcing fibers from waste FRP was developed and experimental tests were performed to study the structural performance of concrete members strengthened with recycled fibres. The purpose of this study is to investigate the effect of recycled glass-fibers from waste FRP on the seismic performance of reinforced concrete beam-to-column joints. Experimental tests were performed for two reinforced concrete beam-to-column joint specimens with the same reinforcements. One joint was strengthened with recycled fibers at a fibre volumn fraction of 1.0%. Cyclic-loading tests were performed on the specimens. Test results showed that use of recycled fibers increased the seismic performance of the reinforced concrete beam-to-column joint significantly.
Fire Resistance Performance of Concrete Filled Square Steel Tube Columns with Fire Spray Protection
Kim, Hae-Soo ; Kang, Jong ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 31~37
DOI : 10.9798/KOSHAM.2011.11.6.031
This study was carried out to compare with existing experimental results and to verify reliability on heat transfer analysis using parameters such as steel thickness and heating time in ABAQUS for evaluation of temperature distribution and fire protection performance according to cross-section location of concrete filled square steel tube column with fire spray protection when fire occurred. As a result, we noticed that the difference of temperature distribution for cross-section location was not so great and the change of steel thickness did not affect temperature distribution.
Seismic Performance Evaluation According to Retrofit Techniques of Nonseismically Designed Shear Wall Type Apartment
Kang, Jong ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 39~44
DOI : 10.9798/KOSHAM.2011.11.6.039
The aim of this study was to investigate the security and reliability of structure based on performance objective on the seismic performance evaluation according to the seismic reinforcing formality of reinforced concrete wall-structural apartment building without seismic design. To evaluate the seismic performance, FEMA 356 was selected as guidelines and pushover analysis was conducted with nonlinear static analysis. The maximum story drift ratio before reinforcement of existing structures in 500 recurrence period was 0.66% which exceeded life safety level, but the performance was improved due to decrease of the safety level (0.47%) after internal and external reinforcement. Moreover, the maximum story drift ratio of existing structures in 2400 recurrence period was 1.31% which exceeded life safety level, but the performance was improved because the ratio appears to be below the safety level (0.93%) after internal and external reinforcement.
A Basic Survey for the Guideline of the Office Occupant Load
Hwang, Eun-Kyoung ; Youn, Ho-Ju ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 45~51
DOI : 10.9798/KOSHAM.2011.11.6.045
Recently the consideration for Occupants` security has been raised as very important design element from the fire by building`s large sized, higher stored, and its complexed. In advanced countries, they are legislating Performance Based Design from building design stage. For this, they were prescribed the occupant load for several space use. Specially because of occupants density is a very important elements for making decision of avaliable safe evacuation time, the advanced foreign countries were enacted the occupant load by the analysed data of fire accident and actual condition survey. However in recent, Korea tried to enact the occupants load, they can not help applying the foreign relevant standardization because of the lack of data. So, the purpose this study is the establishment of the basic data for the guideline of the office occupant load by the actual condition survey of the K building and the standard analysis of the occupants load in the foreign guideline and the domestic architecture design manual.
Behavior of Post-Tensioned Two-Way Slabs Depending on Tendon Layout
Lee, Seung-Chul ; Lee, Young-Hak ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 53~59
DOI : 10.9798/KOSHAM.2011.11.6.053
In this paper, the FE analysis results are presented to evaluate the effects of various tendon layouts on the performance of post-tensioned concrete two-way slab systems. Various arrangements from uniform cable layouts to closely banded arrangements adjacent to column centerlines are considered. The slab is modeled using plate-bending elements in the software package SAP. Equivalent loads based on cable profiles are applied to the slab according to the tendon layout. Moment fields and deflected shapes are compared for the various tendon patterns. Gravity loads are applied in the usual way and superimposed on the results from the equivalent tendon loads to determine net moments and deflections at service load levels. In addition to a study of tendon layouts, the finite-element model is compared with experimental results.
An Experimentally Fundamental Study on Development of Portable Prestressing Device for Pretensioning PSC girders
Yi, Gyu-Sei ; Yoon, Ki-Yong ; Kim, Jong-Suk ; Kim, Yong-Huck ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 61~66
DOI : 10.9798/KOSHAM.2011.11.6.061
In general, pretensioning PSC members are manufactured at the factory. To assemble, they are transported to the site. Due to road conditions, their size is limited. Therefore, until now pretensioning method is only applied to small PSC members. In order to produce large scale PSC members using pretensioning method, they shall be made on site. In this study, a portable prestressing device to produce pretensioning PSC girders on site has been developed. In order to develop a portable prestressing device it shall be safe and stable about jacking force. In this paper, the portable prestressing device to produce 10 m-span pretensioning PSC girders was made. The static loading test was performed to analyze the resisting mechanism of each component of that device. The jacking force was introduced by stretching and anchoring the tendons at its both ends. In the static loading test, the structural characteristics of the developed device are investigated.
A Simulation of Earthquake Loss Estimation with Application of a Site Classification Map
Kang, Su-Young ; Kim, Kwang-Hee ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 67~75
DOI : 10.9798/KOSHAM.2011.11.6.067
Regionally varying seismic hazards can be estimated using an earthquake loss estimation system(e.g. HAZUS). The resulting estimates for actual earthquakes help federal and local authorities develop rapid, effective recovery measures. Estimates for scenario earthquakes help in designing a comprehensive earthquake hazard mitigation plan. Local site characteristics influence the ground motions ensuing from earthquakes. Realistic loss estimates can be obtained using a site classification map, which faithfully portrays the characteristics of the shallow subsurface. We estimated the losses due to a magnitude 6.7 scenario earthquake in Gyeongju, with and without a site classification map. Significant differences in loss estimates were observed. The loss without the site classification map decreased without variation with increasing epicentral distance, while the loss with the site classification map varied from region to region, due to both the epicentral distance and local site effects. The major cause of the large loss expected in Gyeongju is the short epicentral distance. Pohang Nam-Gu is located farther from the earthquake source region. Nonetheless, the loss estimates in the remote city are as large as those in Gyeongju and are attributed to the site effect of soft soil found widely in the area.
A Basic Study on the Analysis Model of Portable Prestressing Device for Pretensioning PSC girders
Byeon, Ji-Seok ; Yoon, Ki-Yong ; Kim, Jong-Suk ; Kim, Yong-Huck ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 77~82
DOI : 10.9798/KOSHAM.2011.11.6.077
In this study, a portable prestressing device to produce pretensioning PSC girders on site has been developed. In order to develop a portable prestressing device it shall be safe and stable about jacking force. In this paper, the analytical model was developed to analysis the device using finite element analysis program ABAQUS. In the previous study, the portable prestressing device to produce 10 m-span pretensioning PSC girders was made and performed the static loading test. By comparing analytical results with these experimental results, the validity of the analytical model was demonstrated. Using the analytical model, the structural characteristics of each component of the developed device are investigated. The analytical model will be used in researching about various lengths and various analysis of the developed device.
Inter-laminar Shear and Flexural Strength of CFRP Rebar Subjected to Elevated Temperatures
Moon, Do-Young ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 83~89
DOI : 10.9798/KOSHAM.2011.11.6.083
In this experimental study, a reduction in mechanical properties of CFRP reinforcing bars, which is domestically produced, subjected to elevated temperatures was investigated. The inter-laminar shear and flexural tests were conducted on the rebar specimens conditioned in a chamber for specified times at high temperatures. The rebar specimens were exposed to the temperatures, range
, for 0.5 hr~4 hr. Based on the obtained results, linear equations were presented for evaluation of the reduced properties due to the applied conditions. It is predicted that the critical temperature and exposure time were
and 2.5 hr, respectively.
Analysis of Correlation between Percolation of Porous Concrete and Probability Distribution Functions
Chung, Sang-Yeop ; Jo, Young-Kug ; Han, Tong-Seok ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 91~98
DOI : 10.9798/KOSHAM.2011.11.6.091
Concrete is a multi-phase material of which material properties are strongly affected by the phase distribution. Spatial distribution of pore in concrete affects mechanical behavior and percolation significantly. Therefore, a proper method to describe the pore distribution of a material is needed. CT(computed tomography) image is used to examine and to quantify the pore distribution of porous concrete specimens. 3D concrete digital specimens base on the real concrete with different pore ratio are created by subsequent stacking of 2D cross-sectional images from CT. Probability distribution functions such as two-point correlation, lineal-path and two-point cluster functions are used for pore distribution characterization. Correlation between hydraulic conductivity from experiment and probability distribution functions of porous concrete is examined using CT image processing. It is confirmed that probability distribution functions based on CT images are effective in characterizing pore distributions including pore clustering and percolation.
Estimation of Rainfall Quantile using the Probability Distribution Parameter Map in Ungauged Site
Lee, Jung-Sik ; Shin, Sha-Chul ; Kim, Seok-Dong ; Cho, Sung-Geun ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 99~107
DOI : 10.9798/KOSHAM.2011.11.6.099
The objective of this study is to produce a probability distribution parameter map for evaluation of probable rainfall quantile in ungauged site. The rainfall data used in this study are annual maximum rainfalls at 58 stations during the period of more than 30 years for 12 durations. The 16 probability distributions which have been widely used in hydrologic frequency analysis are applied to the basic data and to determine the representative appropriate distribution. The location, scale, and shape parameters of the representative appropriate distribution for each station and each duration are calculated using L-moments method. These parameters are contoured using spatial interpolation, based on the geostatistical method of Kriging to produce parameter maps that depict the spatial variation and magnitude of each parameter. The results of this study are as followings; (1) The GEV distribution is determined as the representative probability distribution in Korea. (2) The parameters for any location in Korea can be estimated using the parameter maps and the rainfall quantile is obtained from GEV distribution equation using parameter about the selected rainfall duration. (3) Comparative analysis of the results shows that the probable rainfall quantiles by the parameter maps are little different from those existing researches. (4) In the result by probability distribution parameter map, rainfall quantile is better easy to evaluate in ungaged site without restriction of return period.
Investigation of Geogrid-Reinforced Flexible Pavement Performance over Expansive Clay
Oh, Jeong-Ho ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 109~115
DOI : 10.9798/KOSHAM.2011.11.6.109
Geogrid-reinforcement is often used in conjunction with unbound base layers (i.e., within the layer or as a subgrade/base interface layer) as a means for enhancing the performance of flexible pavements. In this study, a forensic investigation was conducted on a flexible pavement section in Texas to evaluate the influence of geogrid-reinforcement on pavement performance via field and laboratory experimental programs along with numerical analyses. It was evident that load bearing capacity of geogrid-reinforced segment tended to improve by exhibiting higher resilient moduli of unbound layers through dynamic cone penetrometer (DCP) test. Despite of obtaining high swelling and shrinkage potential of expansive subgrade soils due to moisture change from the laboratory test, field survey indicates that geogrid-reinforcement segment performs superior to the control segment along with less longitudinal cracks and lower international roughness index. In addition, numerical analyses validated the effectiveness of geogrid-reinforcement by yielding longer service lives with respect to rutting. This forensic investigation limitedly affirms that geogrid-reinforcement can effectively enhance pavement performance by mitigating movement of expansive clay.
Development of a Risk Visualization System for Natural Disasters based on GIS
Hwang, Hyun-Suk ; Kim, Chang-Soo ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 117~122
DOI : 10.9798/KOSHAM.2011.11.6.117
As natural disasters have recently occurred on a large scale, the damage caused by them have increased. In particular, there are houses and shopping malls close to beaches or mountains in Busan Metropolitan City where some areas are vulnerable on disasters. It is difficult to analyze detail causes of the damage using its documentations or existing information systems which are mostly developed based on the transaction. We design and develop a GIS-based visualization system to display relative risks of the damage occurred by natural disasters such as flooding, wave-storms, landslides, and windstorms. First, we construct a spatial database based on the risks by considering the association among data each natural disaster. Next, we develop an visualization system based on the risks from the analysis results each disaster. In case of flooding, the system shows the risks as to a river which is divided into some districts. In case of wave-storms, the system expresses damage areas as to the occurred typhoons. The system displays the risks according to the divided water press or rainfall in case of dangerous rock slides and soil slides. The system expresses damage areas according to the categorized damage level and the wave frequency in windstorms. This system can support mangers to realize dangerous areas in case a similar disaster occurs, so they can execute a speed response. In addition, the system can be utilized in constructing hazard maps based on the damage history records.
Development of Estimating Technique on 3D Damage Amount using Digital Camera
Cho, Jae-Woong ; Choi, Woo-Jung ; Kim, Gi-Hong ; Shim, Jae-Hyun ; Choi, Sung-Yeul ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 123~129
DOI : 10.9798/KOSHAM.2011.11.6.123
Recently, as natural disasters like torrential rains and typhoons increase, loss of life and property damage have multiplied. But estimated damage amount for restoration is apt to be influenced by investigator`s subjective judgment because it is still manually calculated in the majority of cases. This makes accurate investigation for damage assessment difficult. Especially in 3D damage assessment, such as soil volume, the results vary widely with the investigators. In many cases, the damages are over estimated. We developed an estimating technique for 3D damage amount, which creates pre-disaster virtual surface using only post-disaster stereo images, and calculates the soil volume from the difference between pre-disaster virtual surface and post-disaster surface. The accuracy of developed technique was verified through Field Investigation System. The error was less than 6.4%.
A Study on Development of Climate Change Adaptation Strategies through County Recognition
Chae, Hee-Mun ; Lee, Sang-Sin ; Lee, Hyun-Ju ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 131~138
DOI : 10.9798/KOSHAM.2011.11.6.131
In the issue of adapting to climate change, the actions and the practices by individuals or local communities are important, and it is an obvious fact that the establishment of adaptive plan by the smallest local government will become a prerequisite for establishing the national level systematic adaptive plan. Additionally, the current circumstance is that the need for establishing an adaptive system is continuously increasing for efficiently adapting to climatie change through the local level understanding on climatie change effects and the establishment of response plan. In this study, the research results on the understanding level per climatie change area by county governments and the climatie change vulnerability evaluation result were comparatively analyzed. The research site is Yeongwol-gun, which is located in southern region of Gangwon-do, and the survey research was conducted with general civilians (366) and public service personnel (78) on the urgency and importance in 9 fields on climate change adaptation. As for the survey research result, the priority order among the areas was determined by calculating the urgency and importance per area by utilizing point scale. The analysis results showed that the scale was high for both urgency and importance in the area of water management and disaster. Overall, it was revealed that importance was high than urgency. This can be said as the implication on the need to implement a long-term plan climatie change adaptive policy rather than implement shortsighted policy under the pressure of urgency. The vulnerability evaluation was conducted by using CCGIS through which climate exposure, sensitivity level & adaptive ability can be considered through the vulnerability concept defined by the IPCC, and the result also revealed that the vulnerability in the area of water management and disaster was relatively high.
A Study on Fire Investigations and Identification of Flame Spread Mechanism of the Oaks according to Forest Fire
Park, Young-Ju ; Lee, Hae-Pyeong ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 139~147
DOI : 10.9798/KOSHAM.2011.11.6.139
In this study, we considered the mechanism of the flame spread and the fire investigation for oaks by forest fire. Cone calorimeter and ignition temperature tester were used as the equipments for this study. The temperature range of non-flame ignition was
for living leaves,
for branches, and
for barks, respectively, which showed the difference by kind of trees. Thus, it was confirmed that the green leaves with high moisture content had relatively high risk of non-flame ignition. Also, the time of flaming ignition was 67 sec for living leaves, 203 sec for branches, and 23 sec for barks measured, respectively. Accordingly, it was confirmed that bark part with very low moisture content was flamingly ignited in a shorter time and its flame persisted for the longest time after ignition. And, it was shown that total thermal emission was
for living leaves,
for branches, and
for barks, which were quite different by kind of trees. Further, it could be confirmed that the oaks was a kind of tree mostly with high thermal emission by part. Thus, it is determined that its community complex has high thermal emission and large fire load so that it can be a critical clue to understand fire path and a useful clue to forecast flame spread and fire intensity by its classification into the area of greatest fire density.
Analysis of Transient Ceiling Jet Waves in a Corridor
Ju, Hyeon-Don ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 149~156
DOI : 10.9798/KOSHAM.2011.11.6.149
As the examples of smoke spread in a corridor, the burn rooms are generally connected through a corridor to environment and a lobby. The wave amplitudes of the velocity of transient jet waves are very important in fire protection systems. The objectives of this study are to estimate mathematically the parameters of the transient jet wave velocities flowing through the unconfined ceiling of the corridor and to derive various related equations with the parameters. The parameters vary according to the wave induced velocity, the natural frequency, the wave number and the mean flow velocity. The transient ceiling jet waves are analyzed by FDS software developed by the National Institute of Standards and Technology, USA. The analyzed results of the smoke layer temperature are compared with the experimental results performed by Jones et al.. The relation of the mean velocity, the heat release rates and the door width is expressed by
the relation of the wave induced velocity, the heat release rates and the door width is expressed by
Comparison of Surface Fuel Moisture after Rainfall in Pine Tree Forests During Spring/Autumn Season in Young Dong Region (Case Study on Surface Fuel and Soil Layer Moisture)
Kwon, Chun-Geun ; Lee, Si-Young ; Lee, Hea-Pyeong ; Cha, Joo-Young ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 157~166
DOI : 10.9798/KOSHAM.2011.11.6.157
The change in fuel moisture in accordance with the number of days after rainfall is an important factor in predicting forest fire dangers and supporting forest fire rangers. Therefore, in order to clear up these forest fire occurrence conditions, forest fire danger levels for surface fuel 0.6 cm or lower, 0.6-3.0 cm, 3.0-6.0 cm, and 6.0 cm or above by fallen leaves layer, humus layer, soil layer, and diameter after rainfall of 5.0 mm and higher in accordance with tree forest density in 2008, 2009 Spring/Autumn Young Dong region have been analyzed. Research showed an approximate 17% fuel moisture which is a dangerous forest fire occurrence level after 4 days from rainfall in medium dense-density areas and 3 days after rainfall in loose-density areas of Spring time in the fallen leaves layer. On the other hand, the humus layer showed a 40% or higher fuel moisture even after 6 days from rainfall regardless of the season, while the upper and lower parts of the soil layer had little change or no change at all. In loose-density areas with 0.6cm or less in Spring time, the fuel moisture displayed a dangerous level in fire forest occurrence after 2 days, and 3days in medium dense-density areas, for loose-density areas with 0.6-3.0 cm in Spring time it showed a dangerous level in forest fire occurrence after 3 days, and for medium-density areas, 4 days. In Spring, loose-density areas of 3.0-6.0 cm showed a dangerous level in fuel moisture after 6 days from rainfall, and in the case of 6.0cm or higher, it showed 50% or higher fuel moisture even after 6 days from rainfall regardless of the season.
A Study on Factors to Influence Installation of Household Fire Alarms
Park, Nam-Kwun ; Kim, Twe-Hwan ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 167~174
DOI : 10.9798/KOSHAM.2011.11.6.167
This study aims to analyze factors to influence installation situation and installation of household fire alarms in 6 zones in Kobe, Japan to increase the distribution rate of household fire alarms and enhance local disaster prevention capability. The major results and implications of this study are as follows. It was found that knowledge and information about household fire alarms weren`t effectively delivered to residents, even though they are important elements to improve the installation rate of household fire alarms. And, when analyzing factors to have impacts on installation behavior and awareness of household fire alarms, disaster prevention activity, concern in household fire alarms, recognition of necessity for them and awareness of obligation of installing them were substantially associated with installation behavior and consciousness in the category of characteristics of disaster prevention knowledge, information and consciousness. Also, an income level was more related to them than age and family status in the category of social characteristics.
Evaluation of Liquefaction Mitigation of RAP (Rammed Aggregate Piers)
Cho, Kook-Hwan ; Kim, Hyun-Jung ; Park, Yang-Hoo ; Bae, Kyung-Tae ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 175~181
DOI : 10.9798/KOSHAM.2011.11.6.175
The Rammed Aggregate Piers(RAP) is the method to reduce the possibility of liquefaction by accelerating drainage and increasing shear resistance, which promotes dissipation of pore pressure occurred by vibration. Thus, this study investigates the reduction effect of liquefaction performing Shaking Table Test on soft ground. The reduction effect of excess pore pressure and characteristics of settlement of untreated and reinforced ground conditions were studied by varying ground acceleration and area replacement ratio. In results, the reduction effect of liquefaction is increased 10, 2.5, and 1.5 times from ground acceleration 0.1, 0.2, and 0.4(g) respectively.
Comparison of Substructure Stiffness Evaluation Techniques under Pavement in Sequences of Construction of Pipe Installation
Lim, Yu-Jin ; Park, Jae-Bum ; Hwang, Jung-Kyu ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 183~189
DOI : 10.9798/KOSHAM.2011.11.6.183
Pipe installation following excavation of pavement and subsoils induces settlements, cracks and bad roughness near utility cut. This study is to use PMT and LDWT in order to evaluate stiffness and/or degree of compaction of sublayers and backfill in utility cut section because no specially designed efforts for evaluating stiffness condition of the substructures below new pavement after pipe installation are offered for the sections. From test results of PMT, comparable stiffness and/or degree of compaction in recompaction process is not obtained comparing to that of the existing sublayers before excavation. It is verified that LDWT comparing to PMT is effective only to get stiffness and/or degree of compaction within limited depth from surface of refill materials, but it is not useful to know stiffness of substructures in full-depth in case of utility cut. A numerical study is performed also for getting information about behavior of utility cut section with changing stiffness of the sublayers.
Analysis of the Clay Behavior around Vertical Drains based on the Elliptical Cavity Expansion Theory
Ahn, Jae-Hun ; Lee, Han-Min ; Lee, Youn-Seok ; Kim, Yun-Tae ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 191~196
DOI : 10.9798/KOSHAM.2011.11.6.191
Vertical drains are widely used to expediate the consolidation of clay soil. During the installation of the drains, the clay is disturbed due to penetration of mandrel, which negatively affects much the rate of consolidation. Therefore it is very important to understand the installation procedure and its effect to reasonably assess the performance of vertical drains. In this article, the elliptical cavity expansion theory is developed in an attempt to simulate the installation of rectangular mandrel. As the suggested elliptical cavity expansion theory is analyzed in numerical modelling framework, it can easily be used with any constitutive model required, which is not the case of the analytical solution framework. The developed elliptical cavity expansion theory was utilized with the Modified Cam-Clay model, and the installation procedure of vertical drain was successfully simulated.
Analysis on Scouring Characteristics by Submerged Floating Structure
Choi, Heung-Sik ; Lee, Chang-Hun ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 197~206
DOI : 10.9798/KOSHAM.2011.11.6.197
The scouring characteristics due to submerged floating structure which is affecting river bed changes are analysed by experiments. The critical scouring which initiates the movement of bottom substrates accompanying the erosions of luff, tunnel, and lee-wake is suggested according to the relative location(
/H) of the distance between the center of submerged floating structure and river bed over the water depth. The scouring depths accompanying erosion increase with the increasing of Reynolds, Froude, and Shields parameters governed by velocity. The tunnel erosion is dominant at the Froude of 0.65~0.67 according to the relative location(
/H) and the lee-wake erosion induced equilibrium scouring is progressed steadily over velocity increasing. The numbers of Reynolds and Froude result in greater relative scour effect than Shields parameter. The regression equations for equilibrium scouring depth(
/D) are suggested with Reynolds, Froude, and Shields parameters and the additional parameter(
/D) of the distance between the center of structure and river bed over the diameter of submerged floating structure which show the different scouring phenomena with
Development of a Future Disaster Risk Assessment Model for Climate Change Using Bayesian GLM and Statistical Downscaling Model
Kwon, Hyun-Han ; Myeong, Soo-Jeong ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 207~216
DOI : 10.9798/KOSHAM.2011.11.6.207
This study aims to develop a future disaster risk assessment model for climate change. A linear regression model, which has been widely used in previous studies, has limitations such as (1) the underlying probability distribution assumes to be Gaussian and (2) predicted values from the model are often given in negative numbers that are not appropriate in our case. In the present study, a Bayesian GLM-based disaster risk assessment model is introduced in conjunction with relevant predictors. Predictors were initially derived from daily precipitation data. The data that were finally put in the model as main predictors were (1) the number of consecutive cases of over 80 mm precipitation that lasted less than 10 days, and (2) the heaviest rainfall of the year. A nonstationary Markov chain downscaling model using KMA A2 climate change scenario as inputs was adopted to construct future rainfall scenarios in Gangwon, Seoul, Chungnam and Jeju, and the required rainfall predictors were extracted from the constructed scenarios. It was found that the proposed model could predict 90% of the disaster risks in the flood-prone areas such as Gangwon, Seoul and Chungnam. However, the proposed model failed to predict for the nonflood-prone area of Jeju Island. Future disaster risk variability was assessed using probability density function. The probability density function shifted toward the upper tail for all the areas, meaning increased disaster risks under climate change. Based on the results, this study claims that the proposed Bayesian GLM model is able to take into consideration the increased variability associated with climate change and thus can be effectively used in estimating future disaster risks.
Numerical Investigations of Flood Level Reduction via Securing Lateral River Space for Extreme Flood
Kang, Hyeong-Sik ; Kim, Sung-Eun ; Hong, Hyun-Jung ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 217~226
DOI : 10.9798/KOSHAM.2011.11.6.217
In this study, the water surface elevation reduction via securing lateral river space were investigated for extreme 500 year frequency flood in the Nakdong river basin. Also, the GIS analysis on the Nakdong river space was carried out. The HEC-RAS model was used to calculate the water surface elevation in the Nakdong river and its tributary rivers before and after Nakdong river project. For the model verification, the water surface elevation was simulated and compared with measured data at 6 water surface monitoring points of the flood season in 2007. Through the GIS analysis, the change of land use, low land and inundated regions between 1975 and 2007 were also investigated. In addition, the reduction of water surface elevation was analyzed based on washlands in literature and farmlands suggested in this study. The computed water surface elevation was decreased by maximum 0.65 m due to storage and detention of floodwater. When there were no washlands in the Nakdong basin, the dangerous sections where freeboard is below 1 m was about 2%. However, when the lateral river space was secured, the dangerous sections are only below 0.4%.
An Analysis Method of 1D Hydrodynamic Model Based on GIS for Flood Inundation Mapping
Kim, Byung-Hyun ; Choi, Seung-Yong ; Han, Kun-Yeon ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 227~235
DOI : 10.9798/KOSHAM.2011.11.6.227
Flooding as one of the major natural disasters affects country`s economy. Most country is establishing a flood inundation maps as a non-structural measures to prevent damages from an abnormal flooding over the design criteria of hydraulic structures such as dams, storages, and levees et al. This study suggests method to establish GIS based inundation map induced by dam-break flood simulated by 1D hydrodynamic model(DAMBRK). In this study, the dam-break hydrograph were simulated by various scenario events and especially for the extreme event, peak discharge, peak water surface elevation, arrival time of flood wave and peak water surface elevation are calculated by flood routing at the control points and peak water surface elevation was compared with levee height to detect inundation. In addition, the detailed flood inundation mapping processes at each water level linking with GIS are presented in this study. The proposed method to establish a flood inundation map is able to complement the limitation of 1D hydrodynamic model in analyses of flood plains.
Establishment and Application of 2-Dimensional Flood Inundation Analysis System by the Collaboration of River and Lowland in Nam River Basin
Park, Se-Jin ; Choi, Hyun-Gu ; Huh, Yun-Hyoung ; Han, Kun-Yeun ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 237~247
DOI : 10.9798/KOSHAM.2011.11.6.237
Due to the recent proliferation of hurricanes and heavy rains, occurrence probability of the collapse of river banks and overflow has increased and has brought about large loss of life and severe property damage in lowland. It is imperative information related to the collapse of levee and overflow systems, flood inundation ranges and overflow spots be generated. Real damage causes include flood waves; understanding streams of flood waves as they flow into the lowland is vitally important. The purpose of this study is to generate data that will protect life and the property of residents in damage areas. Flood analysis is preformed to prepare for emergency situations in lowland due to the collapse of dams and river banks due to extraordinary foods and severe rains. Additionally, through simulation and analysis related to flood distribution patterns in lowland, forecasted inundation depth and time, range of flood, and estimated size of damage expectation can be generated. Data targets include the Nam River watershed using the FLDWAV model. Calculating the water level in lowland and introducing flooding hydrograph are vital to success. This is all related to the collapse of river banks and takes into consideration analysis of flood waves and collapse patterns of river banks. Using this data to create a two-dimensional flood model and by examining flood wave transfer characteristics at the point of real bank collapse, progress can be made. Calculating the range of flood, inundation depth and time in lowland, comparing and reviewing results with actual data and flood marks that showed the goodness of fit is over 90% is key. Calculate the range of flood data by assuming extreme situation of 200 years frequency on the same region, these results are able to contribute establishment of flood damage mitigation measures.
Analysis of Overflow Volume Reduction Effect by Sewer Networks Optimization in Urban
Park, Jong-Ryul ; Lee, Jung-Ho ; Choi, Woo-Jung ; Jeong, Sang-Man ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 249~257
DOI : 10.9798/KOSHAM.2011.11.6.249
It is general to design the sewer network in current urban basin to calculate the minimum construction cost depending on sewer route setting of the shortest distance, and precedent researches on optimal design of sewer network is focused on cost-benefit of sewer network. Also, regional torrential rains currently occurred frequently increase the risk of local heavy rainfall in the urban basin with increasing of impermeable areas due to urbanization while exceeding of discharge capacity in the urban basin sewer network, so limitations on existing sewer design have came to the fore. Thus, this study has control the flow changes in pipes as the function objective that can be controlled depending on configurations of sewer through controlling of superposition effects between runoff hydrograph to determine the minimum overflow volume optimal sewer network focusing on that optimal sewer network to maximize the flooding prevention effect, and through application of excessive rainfall events by design frequency 10 years, reduction effects of inundation have been analyzed. Resulting in that, in case of overflow volume minimum sewer network, among 33 nodes, 20 sewers were connected to other direction than current sewers, and overflow volumes for each point about excessive rainfalls show that reduction rate against current sewer network was between 24% and 46%.
Investigation about Design Parameter of Levee using Numerical Model
Park, Jae-Hong ; Kim, Sang-Ho ; Lee, Chang-Hee ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 259~268
DOI : 10.9798/KOSHAM.2011.11.6.259
Levee breach analysis model is developed with levee failure by river flood. This model can calculate levee overflow based on hydraulic theory, analyze inundation depth on the protected area using these results. The enlargement of levee breach width is changed by levee material properties and formation. Detailed parameters are as follows-porosity, uniformity, friction angle, cohesive strength and slope of levee etc. In this study, levee failure sensitivity on geotechnical design parameters is reviewed using numerical analysis model. And it is supposed to help establish design standard of levee design. For these purposes, sensitivity analysis is performed with levee design parameters - geometric and soil mechanic parameters, and the results can be used for basic data in levee design. The results of sensitivity variation on individual parameters shows that mean diameter have the most effect on the maximun breach flowrate, followed by the up and downstream slope, uniformity, porosity, friction angle, cohesive strength etc.
A Comparison of Nonstationary Frequency Analysis Using Successive Average and Moving Average Method
Kwon, Hyun-Han ; So, Byung-Jin ; Yoon, Phil-Yong ; Kim, Tae-Woong ; Hwang, Seok-Hwan ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 269~280
DOI : 10.9798/KOSHAM.2011.11.6.269
This study employed a nonstationary frequency analysis to consider a trend with successive average and moving average method that are used to derive a relationship between mean of annual maximum rainfall(MAMR) and Gumbel parameters. The Mann-Kendall test is applied to determine the changing trend of the successive and moving average method based MAMR for 62 weather stations. Mann-Kendall test of trend shows an increasing and decreasing trend (p-value<0.1) of MAMR for Gwangju and Miryang station, while no significant trend is observed for Goheung station, and theses three stations were used to assess performance of the proposed model. This study confirmed variability of design rainfalls according to the identified trends for all the cases. The successive average method was overall insensitive to short-term variability because of accumulating the MAMR. The moving average method showed better performance in terms of recognizing short-term variability. There are advantages to have more strong relationship between MAMR and Gumbel parameters compared to the successive average method based MAMR. On the other hand, the moving average method is more or less sensitive to the extremes so that the estimated results can be unreliable for limited-size data sets. This study finally evaluated changes in 100-year design rainfall for the year 2030. The design rainfalls based on the successive average and the moving average method are expected to increase by about 8% and 18% across Korea, respectively.
Experimental Study for Analysis of Flood Mitigation Effect by Detention Basin
Kim, Hyung-Jun ; Bae, Deok-Won ; Yoon, Kwang-Seok ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 281~291
DOI : 10.9798/KOSHAM.2011.11.6.281
Detention basin is highly effective hydraulic structure which is available for flood mitigation and ecological characteristics. However, analysis of flood mitigation by detention basin is performed with numerical approaches only, there is not enough data obtained by experimental observation. In this study, physical experiment were performed under unsteady flow condition to analyze flood mitigation with detention basin. Various design factors such as location, later weir height and extent of detention basin were considered in this experimental observations. As the distance from detention base to target location become closer and later weir height become higher, we can expect more effective flood mitigation. As the area of detention basin area become lager, we also expect more higher flood mitigation effects. But, the flood mitigation effects from detention basin would converged to critical value. The obtained data will be useful for following studies about detention basin.
Development of Techniques for Revetments Design Around River-Crossing Structures
Bae, Deok-Won ; Kim, Hyung-Jun ; Yoon, Kwang-Seok ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 293~299
DOI : 10.9798/KOSHAM.2011.11.6.293
The river-crossing structures are constructed to maintain river bed. Revetment is a structure which is installed around connection to protect weak points between levee and river-crossing structures from flood. It is, however, possible that revetment is collapsed by local velocity which is increased around structures. In addition, it is possible that design value is overestimated or underestimated since the stability of revetment is assessed based on empirical judgments without clear criteria. This study is focused on the improvement of techniques for revetments design around river-crossing structures through laboratory experiments on riprap and concrete block. The experimental results were used to figure out methods applying local velocity in the condition of collapse. As a result, the empirical formula, such as the sizes and the stability length of revetment, reflecting local velocity on the slope was proposed.
Design Methodology Study on the Steel Breakwater III. Morphological Changes behind a Permeable Detached Steel Breakwater
Lee, Jung-Lyul ; Kweon, Hyuck-Min ; Lee, Joo-Yong ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 301~308
DOI : 10.9798/KOSHAM.2011.11.6.301
In order to solve various problems associated with gravity-type breakwaters, the permeable breakwaters are recently taken into account as an alternative tool to control wave heights to an acceptable level. In particular, they are favored from the point of view of coastal environment, since they do not in general partition the natural sea. In this study, therefore, we present a morphodynamic model applied to scattering wave fields. The numerical solutions are compared with experimental data on wave profiles and morphological change rates under a surface-piercing breakwater system. Our numerical study involves several modules: 1) nonlinear wave dynamics analyzed by a plane-wave approximation, 2) suspended sediment transport combined with sediment erosion-deposition model, and 3) concurrent morphological changes. Scattering waves are solved by using a plane wave method without inclusion of evanescent modes.
Development of a Finite Difference Model for Tsunami Propagation
Ha, Tae-Min ; Ahn, Seong-Ho ; Chun, Si-Young ; Cho, Yong-Sik ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 309~316
DOI : 10.9798/KOSHAM.2011.11.6.309
The linear shallow-water equations have been used frequently to simulate transoceanic propagation of tsunamis instead of the linear Boussinesq equations. In previous studies, the physical dispersion is compensated by using the numerical dispersion generated from the leap-frog finite difference scheme. However, the linear Boussinesq equations can be directly solved because computer technique has been improved dramatically. In this study, a new finite difference scheme is proposed to discretize the linear Boussinesq equations. The newly developed model is applied to propagation of a Gaussian hump over a constant water depth. The model is then verified by comparing predicted results with analytic solutions. Predicted results agree well with analytical solutions. The model can be directly applied to simulation of transoceanic propagation of tsunamis.
Estimation of Delivery Pollution Load by the Runoff Characteristics of Soyang Lake Basin
Park, Soo-Jin ; Baek, Kyung-Won ; Kang, Young-Bok ; Choi, Han-Kuy ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 317~324
DOI : 10.9798/KOSHAM.2011.11.6.317
This study selected the upstream of Soyang Lake and investigated the flow and water quality during rainfall and non-rainfall periods in 2008 and 2009 and inquired into the changing conditions of concentration of water quality depending on runoff capacity. Water quality grades were compared, using FWMC and as a result, it was confirmed that the first and second grades during the non-rainfall period and the water condition aggravated below the third grade during the rainfall period. And as the flow gained due to a great increase in the discharge of contaminated substances during the early rainfall period, small amounts of contaminated substances occurred continuously. Also, this study suggested regression equation of pollution load depending on the flow in each drainage area through regression analysis and computed annual delivery pollution load in drainage areas, using annual rate of runoff capacity.
Kinetic Study of Adsorption and Photocatalysis on Sulfamethoxazole Degradation by
Chun, Suk-Young ; Chang, Soon-Woong ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 325~330
DOI : 10.9798/KOSHAM.2011.11.6.325
In this study, it was found that adsorption and photocatalysis methodology of antibiotics such as Sulfamethoxazole with various catalyst(Titanium dioxide;
, Hydroxyapatite; HAP). And compared the result of determined kinetics such as pseudo first order, second order and intra particle diffusion model.
/HAP adsorbent were found to follow the pseudo second order reaction. And in the result of applied intrapaticle diffusion model, the constant of reaction rate were $TiO_2
Computation of Non-point Source Pollutant Loads based on Hydrological Model according to Land Uses in Residential Area
Shon, Tae-Seok ; Cho, Eun-Young ; Lee, Tae-Sam ; Shin, Hyun-Suk ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 331~339
DOI : 10.9798/KOSHAM.2011.11.6.331
The precedent researches of non-point pollutants source analysis in urban area have been computed load based on representative basin which is located at the end of object watershed. The result of this, pollutants load has been underestimated or overestimated than status of land uses in area. Thus, the computation of unreliable load is no longer suitable for non-point pollutant source quantitative analysis. Moreover, there is demand of load computation method considering land uses of object watershed based on non-point pollutant source runoff characteristic. In view of these aspects, the research is not only required to consider separated sub-basins which are distributed according to land uses, but also needed to develop a suitable model which is reflected rainfall-runoff relation. This study distributes urban area by land uses in four kinds and the residential area is especially chosen for object watershed. The on-site monitoring has been performed to collect data in object watershed as well. On top of that, the SWMM was developed using monitoring data and applied to "Oncheon-Guje stream" in Busan city to compute reliable pollutants load considering residential land uses. Computed load using SWMM modeling is the highest in 1999 which is the year of the highest precipitation during 1998-2007. This results show that rainfall-runoff relation is reflected well through SWMM to compute non-point pollutant loads. Finally, this study tried to compared with precedent study`s results to review and confirm usefulness of this study in order to reconsider its application in Korea.
Gilanchon Watershed Water Quality Simulation Using QUALKO & QUAL2K
Kim, Eung-Seok ; Park, Moo-Jong ; Kang, Doo-Kee ; Choi, Hyun-Il ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 341~347
DOI : 10.9798/KOSHAM.2011.11.6.341
This study has implemented QUALKO and QUAL2K models for the Nakdong River watershed, which can simulate the change in organic matters due to growth and death of algae. Also the two models simulated three water quality factors such as BOD, T-N, and T-P to understand characteristics of the both models. The model errors, differences between observed and simulated values, result in ranges of 25.99%-26.57% for BOD, 2.34%-3.29% for T-N, and 3.57%-7.14% for T-P, respectively. The model error for BOD is relatively larger because it is simulated by the meling and hydrolysis of Detritus. The simulated result of T-N was more accurate in QUALKO than QUALK2K. The trend of T-P increases from upstream to downstream due to increases of organic P and dissolved P from point sources along the river. In general, the results from QUALKO and QUAL2K models were similar and the model errors from the both models produce no significant differences. The calibration of parameters in models is required to improve model predictability.
Spatio-Temporal Analysis of Future Extreme Drought Events Using a Conceptual Soil Water Model
Kim, Sang-Dan ; Lee, A-Yeon ; Lee, Jae-Woon ; Kim, Tae-Woong ;
Journal of Korean Society of Hazard Mitigation, volume 11, issue 6, 2011, Pages 349~356
DOI : 10.9798/KOSHAM.2011.11.6.349
In this study, the impact of climate change on the spatio-temporal behavior of extreme drought events is investigated by comparing drought severity-area-duration curves under present and future climate conditions. In order to consider future increasing trends in air temperature, the standardized soil water index is introduced. The standardized soil water index is calculated using a conceptual soil water model forced by daily air temperature and daily precipitation data. In our climate-change impact experiments, the future climate is based on two GCMs(CGCM3.1-T63 and CSIRO-MK3.0). As a result, in both cases of CGCM3.1-T63 and CSIRO-MK3.0 the future drought risk is likely to increase. Such results indicate that a climate change vulnerability assessment for present water resources supply system is urgent.