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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 8, Issue 6 - Dec 2008
Volume 8, Issue 5 - Oct 2008
Volume 8, Issue 4 - Aug 2008
Volume 8, Issue 3 - Jun 2008
Volume 8, Issue 2 - Apr 2008
Volume 8, Issue 1 - Feb 2008
Selecting the target year
Heated temperature and Range of the Oxy-acetylene Cutting Reinforcing Bar by Simulation and Experiment
Kim, Bong-Joo ; Kim, Jae-Hun ; Cho, Byoung-Hoo ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 1~5
The object of this experimental and simulation study is to find out heated temperature and range from the Oxy-acetylene cutting point of reinforcing bars (D10, D13, D16, D19, D22, D25 for each cases of SD3O and SD40) in room temperature (
). This cutting is under the condition that a skilled worker cut one bar per a time. The results are these. 1. The temperature of the point 1 of reinforcing bars cut with Oxy-acetylene cutter is over 700
, but the temperature of the point 2 of reinforcing bars cut with Oxy-acetylene cutter is under 200
2. The temperature of the point that is apart 2cm from Oxy-acetylene cutting point is not over 200
, so reinforcing bars has not transform to be brittle. The results of simulation for temperatures of the each point apart from Oxy-acetylene cutting point is similar to upper experimental results.
A Case Study of Bridge Scour Vulnerability Evaluation and Prioritization for National Highway Bridges in the National Capital Region
Park, Jae-Hyun ; Kim, Jeong-Hun ; An, Seong-Chul ; Lee, Ju-Hyung ; Chung, Moon-Kyung ; Kwak, Ki-Seok ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 7~21
Foundation failure due to bridge scour during floods is the leading cause of bridge failure. Performed were the evaluation of bridge scour vulnerability and prioritization on real bridges registered in the National Highway Bridge Inventory of the capital region. The case studies for 30 national highway bridges consist of site investigation including boring test, bridge scour analysis fur the design flood, bearing capacity evaluation of the bridge foundation before and after scour, comprehensive evaluation of bridge scour vulnerability, and prioritization. Nine of 26 spread (feting bridges showed the potential future vulnerability to scour with significant decrease in the bearing capacity of foundations due to scour and the remaining 17 spread footing bridges were expected to maintain their stability to resist the effects of scour. Three of 4 pile foundation bridges exhibited considerable decrease in the bearing capacity of foundation after scour.
Properties of Ultra High Performance Fiber Reinforced Cementitious Composites Mixed with Limestone Powder
Han, Sang-Mook ; Wu, Xiang-Guo ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 23~30
UHPC has high performance, high strength and excellent mechanical properties. Moreover UHPC(Ultra High Performance Cementitious Composite) has advantage to reduce cross section under the same load compared with other kinds of concrete. But silica fume which is imported from foreign country has a abundant portion in UHPC mixture in comparison with normal concrete. This is one of the main reason to raise the construction cost. Superior mechanical properties of UHPC due to the optimum filling composition can be changed by replacing the very fine ingredient. The purpose of this research is to grasp the characteristic of UHPC which silica fume and silica flour is replaced with limestone powder. This experiment can be divided into three classes according to the kinds of replacement. The compressive strength and flow of all types were measured and microstructure and hydration phenomena for comparing RPC were analyzed by SEM, XRD, NMR method. As a result, the replacement can be considered to be effective by for the decrease of the UHPC structure construction cost and improvement of the fresh UHPC.
Seismic Performance of Internally Confined Hollow RC Column with Corrugated Steel Tube
Han, Taek-Hee ; Kim, Jong-Min ; Kang, Jun-Suk ; Kang, Young-Jong ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 31~38
A column test was performed far a new-type column with a quasi static test. An internally confined hollow reinforced concrete column with a corrugated steel tube (ICH RC-CT column) was tested to evaluate its seismic performance. And also, a general solid RC column was tested fur the comparison. The test was performed as planned drift levels. The lateral displacements and the lateral loads of column specimens were measured during tests. From the test results, the ICH RC-CT column showed smaller energy absorbing capacity than a solid RC column but showed the almost equal energy ductility and equivalent viscous damping ratio to those of the solid RC column.
Modified Equivalent Radius Approach for Soil Damping Measurement in Torsional Testing
Bae, Yoon-Shin ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 39~43
Determination of strain associated with shear modulus and damping ratio during torsional test is complicated. This is due to nonuniform stress-strain variation occurring linearly with radius in a soil specimen in torsion. A conventional equivalent radius approach proposed by Chen and Stokoe appears to be adequate for evaluating strain associated with shear modulus at low to intermediate strain levels. This approach is less accurate for damping measurement, particularly at high strain. Modified equivalent radius approach was used to account for the nonuniform stress-strain effect more precisely. The modified equivalent radius approach was applied for hyperbolic, modified hyperbolic, and Ramberg-Osgood models. The results illustrate the usefulness of the modified equivalent radius approach and suggest that using a single value of equivalent radius ratio to calculate strains is not appropriate.
A Study of the Modification Factor(B) in the AISC Specification for Elastic Buckling of Web-Tapered Beams
Ryu, Hyo-Jin ; Lim, Nam-Hyoung ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 45~49
This paper investigated the accuracy of the current design formulae for the elastic buckling strength of web-tapered I-beams in AISC-LRFD specification. The basic concept is to replace a tapered beam by an equivalent prismatic beam with a different length, but with a cross section identical to that of the smaller end of the tapered beam. The modification factor, B, is used to account for the stress gradient within the unbraced length and the lateral restraining effects offered by the adjacent segments. The modification factor(B) suggested in AISC-LRFD specification was compared with the finite element method(FEM) results. This paper presented a redefined method to calculate the modification factor(B).
Ultimate Shear Capacity of Prestressed Girder of Ultra High Performance Fiber Reinforced Concrete
Han, Sang-Mook ; Wu, Xiang-Guo ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 51~58
This study is to investigate the ultimate shear load of prestressed girder made of Ultra High Performance Fiber Reinforced Concrete (UHPFRC). Nine girders were tested until failure in shear. An analytical model to predict the ultimate shear load was formulated based on the Two Bounds Theory. A fiber reinforcing model was constituted based on the random assumption of steel fiber uniform distribution. The predicted values were compared with the conventional predictions and the test results. The proposed equations for computing the ultimate shear strength can be used for the ultimate failure status analysis, which could also be utilized for numerical limit analysis of prestressed UHPFRC girder. The established fiber reinforcing theoretical model can also be a reference for micro-mechanics analysis of UHPFRC.
Development of a Conjunctive Surface-Subsurface Flow Model for Use in Land Surface Models at a Large Scale: Part I. Model Description
Choi, Hyun-Il ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 59~63
The surface runoff is one of the important components for the surface water balance. However, most Land Surface Models(LSMs), coupled to climate models at a large scale for the prediction and prevention of disasters caused by climate changes, simplistically estimate surface runoff from the soil water budget. Ignoring the role of surface flow depth on the infiltration rate causes errors in both surface and subsurface flow calculations. Therefore, for the comprehensive terrestrial water and energy cycle predictions in LSMs, a conjunctive surface-subsurface flow model at a large scale is developed by coupling a 1-D diffusion wave model for surface flow with the 3-D Volume Averaged Soil-moisture Transport(VAST) model for subsurface flow. This paper describes the new conjunctive surface-subsurface flow formulation developed for improvement of the prediction of surface runoff and spatial distribution of soil water by topography, along with basic schemes related to the terrestrial hydrologic system in Common Land Model(CLM), one of the state-of-the-art LSMs.
Estimation of Vulnerable Disaster Areas to Establish Busan U-City Model
Jeon, Sang-Soo ; Jang, Hyun-Min ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 65~73
Since the damages caused by disasters increase every year associated with wrenching climatic changes and the diversification of the social structure, the efficient management system is required to reduce damages and an assessment of the vulnerable disaster areas is necessary to prevent and mitigate the damages. In this paper, we have estimated the vulnerable disaster areas based on the records of the past damage histories and performed the risk assessment of the social infrastructures in Busan city to provide the fundamental information for the real-time monitoring system and the systematic approach for disaster prevention system to build V-City model. These results are illustrated by using Geographical Information System (GIS) and the order of vulnerable disaster areas are also estimated.
Damage Analysis of Meteorological Disasters for Each District Considering the Characteristics of a District
Jun, Hwan-Don ; Park, Moo-Jong ; Kim, Guen-Young ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 75~82
Heavy rains and typhoons are the most critical meteorological disaster occurred in the Korean peninsular. Due to the global warming, the magnitude of heavy rains and typhoons is becoming heavier resulting in more damage annually. Therefore, it is required to establish a mitigation plan to reduce the damage from meteorological disasters. To do so, in general, it is better to establish a mitigation plan for each district considering the characteristics of a district than a single mitigation plan for the entire districts without considering the characteristics of an individual district. In this study, we provide fundamental data for establishing a mitigation plan from analysis considering the frequency and damage in monetary value by heavy rain and typhoon with the geological and social characteristics of districts. The annual damage reports published by the National Emergency Management Agency, dated from 1994 to 2003, are used for the analysis. The districts are classified into six categories by the geological and social characteristics. Also, the frequency and damage in monetary value are assessed for each district. Based on them, the damage degree by heavy rain and typhoon from 1st to 4th is assigned to each district. The assigned damage degree is, then, analyzed with geological and social characteristics of each district to show the status of damage by meteorological disasters on the district.
Case Histories of Damage and Improvement Schemes for Human Disasters
Jeon, Sang-Soo ; Kim, Jae-Min ; Jang, Hyun-Min ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 83~90
Social infrastructures have been built when the growth of economy in Korea significantly increases in 1960s. Nowadays, these infrastructures have been aged with an inappropriate maintenance and management and the citizens have rare recognition for human disasters. In addition, the government has law or regulations responding to human disasters but these are not complementary. Since these human disasters have been issued as social problems and have induced social and economic loss, the improvement schemes for human disasters are currently being demanded. In this study, the case histories of damages and improvement schemes with respect to the types of damages for human disasters are comprehensively investigated.
A study on the factors of affecting the acceptance intention for disaster warning information
Sung, Yeon-Seok ; Jeong, Duke-Hun ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 91~96
This research is to investigated to analyze and identify factors which has been impacted area on the level of people' acceptance for disaster warning information. For better results and more reasonably generally accepted the results, the research was targeted people who need disaster warning information by the disaster impact. The damages from disaster are increasing every year. The disaster warning information have been changed by the level of people acceptance for the disaster warning information which has not been enough to satisfy the level of information. The research model has been developed by intergrating 'TAM model' to show theoretical and practical implications of this study. Research hypothesis are verified and analyzed through the SPSS and AMOS program. The main contribution of this research is to enhance effectiveness of disaster warning information to the people who can be damaged from disasters.
Modified Equivalent Radius Approach in Evaluating Stress-Strain Relationship in Torsional Test
Bae, Yoon-Shin ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 97~103
Determination of stress-strain relationship in torsional tests is complicated due to nonuniform stress-strain variation occurring linearly with the radius in a soil specimen in torsion. The equivalent radius approach is adequate when calculating strain at low to intermediate strains, however, the approach is less accurate when performing the test at higher strain levels. The modified equivalent radius approach was developed to account for the problem more precisely. This approach was extended to generate the plots of equivalent radius ratio versus strain using modified hyperbolic and Ramberg-Osgood models. Results showed the effects of soil nonlinearity on the equivalent radius ratio curves were observed. Curve fitting was also performed to find the stress-strain relationship by fitting the theoretical torque-rotation relationship to measured torque-rotation relationship.
Engineering Properties of Flowable Fills with Various Waste Materials
Lee, Kwan-Ho ; Lee, Byung-Sik ; Cho, Kyung-Rae ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 105~110
Flowable fill is generally a mixture of sand, fly ash, a small amount of cement and water. Sand is the major component of most flowable fill with waste materials. Various materials, including two waste foundry sands(WFS), an anti-corrosive waste foundry sand and natural soil, were used as a fine aggregate in this study. Natural sea sand was used for comparison. The flow behavior, hardening characteristics, and ultimate strength behavior of flowable fill were investigated. The unconfined compression test necessary to sustain walkability as the fresh flowable fill hardens was determined and the strength at 28-days appeared to correlate well with the water-to-cement ratio. The strength parameters, like cohesion and internal friction angle, were determined for the samples prepared by different curing times. The creep test for settlement potential was conducted. The data presented show that by-product foundry sand, an anti-corrosive WFS, and natural soil can be successfully used in controlled low strength materials(CLSM), and it provides similar or better properties to that of CLSM containing natural sea sand.
Dependency of Dynamic Behavior of Circular Foundation on Ground and Foundation Characteristics
Ahn, Jae-Hun ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 111~117
The effect of characteristics of ground and circular foundation on the dynamic behavior of the foundation in vertical motion are considered using an approximated analytical solution and a finite element analysis with absorbing (consistent transmitting) boundary. The shear wave velocity of homogeneous ground affects the resonant frequency of the foundation much but has nothing to do with the maximum response amplitude at resonant frequency. The density in this case affects both the resonant frequency and the maximum response. The size and the mass of the circular foundation are related both to the resonant frequency and the maximum response. However, Poisson's ratio has very little effect on dynamic behavior of the foundation. When the ground is not homogeneous but has the layers, different formations of shear wave velocities would also change the maximum response at resonant frequency.
Flow Characteristics and Riverbed Changes Simulation for the Upstream and Downstream Sections of Gongju Bridge
Shin, Kwang-Seob ; Jeong, Sang-Man ; Lee, Joo-Heon ; Song, Pum ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 119~127
The flow characteristics and the aspects of riverbed changes were analyzed for the upstream and downstream sections of Gongju Bridge. The upstream and downstream had complex topography, and the sections had the confluence of tributaries and several structures. In order to simulate the flow characteristics of the target sections, 1D HEC-RAS and 2D RMA2 were applied. As a result, the longitudinal water level of the target sections matched the results of simulated 1D and 2D samples. Also, 2D SED2D were applied to predict riverbed changes. As a result of the simulation, quantitative analysis was able to be performed for longitudinal riverbed changes from the sections of sudden change, bridges, the confluence of tributaries, and bends. Also, the distribution of riverbed changes on the main sections was in close relation to flow velocity. As a result of evaluating the sensitivity of SED2D, the concentration of suspended sediment, the thickness of sand beds, and the size of sand grains affected riverbed changes sensitively. These results will be used to apply the models of riverbed changes in the future.
The Influence of K-ratio and Seepage Velocity on Piping Occurrence
Huh, Kyung-Han ; Chang, Ock-Sung ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 129~138
In case of judging the stability of dike or dam structures which need hydraulic interception, the first thing to do is to examine whether a piping phenomenon occurred or not. Generally, dike or dam structures are constructed while layer compacting is executed, so permeability is likely to be anisotropic- different from each other in hydraulic conductivity in the horizontal direction [
] and hydraulic conductivity in the vertical direction[
]. This study looked into exit hydraulic gradient and Seepage velocity by conducting an Seepage analysis subsequent to various hydraulic conductivity ratios[k-ratio = ky / kx] and examined the influence on piping by comparing & examining critical Seepage Velocity based on critical hydraulic gradient in theoretical equation and critical Seepage Velocity in empirical equation. As the research result, it was found that hydraulic conductivity ratio operates as a very important factor in case the stability against piping occurrence is considered with the concept of critical hydraulic gradient, but relatively the hydraulic conductivity ratio is very low in its importance in relation to the concept of critical Seepage Velocity.
An Analysis of Long-Term River Bed Changes using Surface-water Modeling System (SMS) Model: A case study of the Pochon stream basin
Choi, Min-Ha ; Lee, Seung-Oh ; Ahn, Jae-Hyun ; Yoon, Yong-Nam ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 139~147
More precise estimation of the bed change, primary cause of flood damage, has been recognized significant for designs of levees and other river facilities. In this study, the long-term bed change was examined as the application of the relatively new Surface-water Modeling System (SMS) Model because there has not been broad verification of the model empirically on river of South Korea. This 2-dimensional model was used to examine the bed change of Pochon Stream Basin, a tributary of Imjin River, where heavy rain damages annually occur. First, in order to verify the model, the simulating period was set from 1986 to 1998 because of the existence of the field measurements. Cross sectional field measurements of 1986 were used for the initial condition and output were compared and analyzed with the observed cross sectional data in 1998. As the results of the verification, the comparison in lateral and streamwise bed level between results from the model and the field measurements showed a reasonable agreement except for the some cases of local scours. However, in terms of the quantitative comparison, the change of the bed elevations for each cross section for 1998 was rather underestimated than that of the field measurements.
Improved Parameter Computation Method Applications of Storage Function Model for the Han River Basin
Jeong, Dong-Kug ; Jeon, Yong-Woon ; Lee, Beum-Hee ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 149~158
The parameters of each basin, required for the accurate analysis of flood runoff using Storage Function Model, are estimated. Prior to the estimation, sensitivity analysis and extraction of new regional topographic factors for Han River basin are conducted. Based on the result, the outflow constant of basin model is calculated through regression analysis in relation with pre-flood runoff depth. The storage constant of basin model is derived by the optimum storage constant equation, according to the flood event of each basin. The model using the mentioned parameters was compared with K-Water model of Korea Water Resources Corporation and the model of Han River Flood Control Office, and proved to correspond to the observed hydrograph more.
Information of Flood Estimation using GIS for Three Dimensional Visualization
Lee, Jin-Woo ; Kim, Hyung-Jun ; Cho, Yong-Sik ;
Journal of Korean Society of Hazard Mitigation, volume 8, issue 2, 2008, Pages 159~164
This study simulated the flood inundations of the Nakdong River catchment running through Yangsan, a small city located in the south eastern area of Korea by using the depth averaged two-dimensional hydrodynamic numerical model. The numerical model employs the staggered grid system including moving boundary and a finite different method to solve the Saint-Venant equations. A second order upwind scheme is used to discretize the nonlinear convection terms of the momentum equations, whereas linear terms are discretized by a second order Leap-frog scheme(Cho and Yoon, 1998). The numerical model was applied to a real topography to simulate the flood inundation of the Yangsan basin in Yangsan. The numerical result for urban district was visualization for three dimension. These results can be essentially utilized to construct the three dimensional inundation map after building the GIS-based database in local public organizations in order to protect the life and property safely.