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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 10, Issue 6 - Dec 2010
Volume 10, Issue 5 - Oct 2010
Volume 10, Issue 4 - Aug 2010
Volume 10, Issue 3 - Jun 2010
Volume 10, Issue 2 - Apr 2010
Volume 10, Issue 1 - Feb 2010
Selecting the target year
The Development of Structural System of Long-span Greenhouse Using the Pre-Engineering Building System
Oh, Myoung-Ho ; Kim, Yong-Seok ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 1~7
Rural facilities need to be changed to be industrialized and long span structures due to accelerating aging of the rural population. In this study, the optimized structure was developed by applying Pre-Engineered Building System using the tapered member to make that the Korea standard green house has a long span. When considering design load, reasonable values were adapted by reviewing existing design codes. As a result, applying pre-engineered building system was efficient in structural system that has span longer than 16 m. And it was concluded that the increase with the longitudinal span from 4 m to 12 m was more efficient in aspect of steel amount.
Estimation of Basic Wind Speeds Reflecting Recent Wind Speed Data
Choi, Sang-Hyun ; Seo, Kyung-Seok ; Sung, Ik-Hyun ; Lee, Su-Hyung ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 9~14
Recent increase in the strength and frequency of typoons due to climate change claims reconsideration of the design wind load in existing design codes for civil engineering structures in which the basic wind speed is estimated based on meteorological data by mid 1990s. In this paper, based on wind speed data at 76 observatories in Korea from 1961 through 2008, the basic wind speeds which can be utilized in designing civil engineering structures including buildings and bridges are estimated using the statistical process. The return period of the wind speed for each location is determined using the Gumbel distribution. The results for considered locations are compared to the existing design codes. Also, for design applications, the wind speed map, which classifies the country into four basic wind speed zones, is proposed using the resulting basic wind speeds.
Service Life Prediction of R.C. Structures Considering Chloride Binding
Lee, Chang-Soo ; Park, Jong-Hyok ; Kim, Young-Ook ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 15~22
Chloride-induced corrosion of steel bars in concrete exposed to marine environments has become one of the major causes of deterioration in many important facilities made of reinforced concrete. A study on chloride penetration in concrete has developed through long period exposure test along seawater, assesment of chloride ion diffusion by electrochemical techniques and so on. However, reasonable and exclusive chloride penetration model considering concrete material properties with mixture, degree of hydration, binding capacity has not been established. Therefore, in this paper, chloride penetration analysis of non-steady state is accomplished with material properties of concrete. Comparing with the results of analysis and chloride ponding test, we could accept the effect of binding capacity on chloride penetration in concrete and these results could be applied to a service life prediction of R.C. structures submerged in seawater. Therefore, there are 20~40% differences of service life to SHRP prediction.
Adaptive Finite Element Mesh Generation Schemes for Dynamic Structural Analyses
Yoon, Chong-Yul ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 23~28
Reliable dynamic analysis is essential in order to properly maintain structures so that structural hazards may be minimized. The finite element method (FEM) is proven to be an affective approximate method of structural analysis if proper element types and meshes are chosen. When the method is applied to dynamics analyzed in time domain, the meshes may need to be modified at each time step. As many meshes need to be generated, adaptive mesh generation schemes have become an important part in complex time domain dynamic finite element analyses of structures. In this paper, an adaptive mesh generation scheme for dynamic finite element analyses of structures is described. The concept of representative strain value is used for error estimates and the refinements of meshes use combinations of the h-method (node movement) and the r-method (element division). The validity of the scheme is shown through a cantilever beam example under a concentrated load with varying values. The example shows reasonable accuracy and efficient computing time. Furthermore, the study shows the potential for the scheme's effective use in complex structural dynamic problems such as those under seismic or erratic wind loads.
Behavioral Characteristics of Precast Concrete Slab using Wheel Load Tester
Park, Seok-Soon ; Kim, Nak-Seok ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 29~34
The main objective of this research is to present the behaviors of precast concrete slab under moving wheel loads. The simulated moving wheel tester and precast concrete slab were designed for this research. In particular, a comparative analysis between the structural analysis and the moving wheel load test was evaluated in connection parts, deformation, bedding layer of concrete slab panels. In the comparisons of the test results from static and moving wheel loads, the maximum deformations were similar. It should be noted that the deformation of panel 2 from the static loading test was larger than that of other panels, while the deformations of panels 1 and 3 were more noticeable than that of panel 2.
Development of Base Concrete Block for Quiet Pavement System
Lee, Kwan-Ho ; Park, Woo-Jin ; Kim, Kwang-Yeom ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 35~42
The rapid economic development induced the massive road constructions, becoming bigger and high-speed of the vehicles. However, it brings lots of social problems, such as air pollutions, traffic noise and vibration. Special concrete block for the base course of asphalt pavement is needed to decrease traffic noise such as tire's explosive and vehicles sound, applying Helmholtz Resonators theory to asphalt pavement. If it is applied to the area where it happens considerable noise such as a junction, the street of a housing complex and a residential street, it is one of considerable method to solve the social requirements of noise problem. This research examines couple of laboratory tests for the sound absorption effect of the concrete block and the base concrete block. There are specimens which is fixed hall-size, space, depth as the condition of this research, and these are analysed of noise decrease effect using different condition of the first noise of each vehicle. As a result of analysis data according to vehicle noise volume, measurement distance, a form and size of the hall using the base concrete block, the use of special concrete base showed a good alternative solution for decreasing traffic noise level, from 4 dB to 9 dB.
Analysis of Technical Problem for Soil Compaction by Gyratory Compactor
Lee, Kwan-Ho ; Jang, Tae-Young ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 43~48
Proctor test A or D method of compaction is the most common laboratory test for investigation of subgrade soil characteristics, however, compression type using roller is used in the field. The differences between laboratory and field compaction have considerable error as application to subgrade soil properties of laboratory test. The investigation of compacted soil is carried into effect to solve the problem. The gyratory compactor which is made to reproduce the field density of asphalt mixture, coming from traffic loads, has an advance to compact it similar to arrangement of field aggregate particles. This gyratory compactor has several problems of investigation of compacted soil, because it has designed to make initial asphalt specimens. The main objectives of this research are grasping problems when compacted soil test using the gyratory compactor and showing solutions. It has made a comparative study of difference of the percentage of water content and weight, which are before and after compaction, about the pressure of compaction, frequency of compaction and speed of compaction. And it also has investigated finding maximum percentage of water content which not occur change of percentage of water content after compaction and searching how has an effect on drawing compaction curve.
Development of GIS-based Debris Flow Simulation Program
Wie, Gwang-Jae ; Lee, Young-Kyun ; Lee, Dong-Ha ; Suh, Yong-Cheol ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 49~55
This study describes a development of GIS-based program called Debris Flow Analyzer for simulating the hazard extent of debris flow on the assumption that is uniform continuous, incompressible, unsteady. The Debris Flow Analyzer was designed to process debris flow numerical simulation with Finite Difference Formulation; smoothed DEM, slope, debris flow directions, extract valley, debris volume, water volume, debris flow moving speed, effective viscosity, dynamic friction coefficient. Also, it is expected that we can be improved the inform of debris flow hazard map by Google Earth.
A Study on the Financial System for Public Fire Services
Cho, Kil-Young ; Min, Byoung-Ik ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 57~63
Central government moves welfare, education, and public fire service that need a lot of budget to local governments. But, central government don't give a enough finance support to local governments to implement those services. Therefore, local government suffer from the financial pressure. Fire service is supplied by province government in Korea. Public facilities tax is an object tax for fire service in province government. But, since total revenue of public facilities tax is just about 30% of fire service budget, the financial pressure of local governments has been increasing and the fire services could not been improved comparing with the increasing demands for the services. The purpose of this article is to examine a stable tax system for fire service. To do so, this study analyzes the fire public service budget, finds out some problems, and compares with developed countries to solve these problems.
A Numerical Study on Characteristics of Flood Wave Passing through Urban Areas (2) : Application and Analysis
Jeong, Woo-Chang ; Cho, Yong-Sik ; Lee, Jin-Woo ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 65~72
In this study, the effects of urban areas against flood waves due to a dam failure were numerically investigated based on the two laboratory experiments and the predicted water surface elevations at specific points showed good agreement with available measurements. In the first experiment, a relatively high water depth and the delay effect of flow at the front of urban areas are observed. The urban areas may become a large obstacle against smooth propagation of flood wave. In the second one, as the inflow increases, moreover, the water surface elevations can be classified into abruptly decreasing portion and slowly decreasing portion, and the first arrival time to the front of urban area is decreasing with the increasing inflow.
Optimal Design of Water Distribution System considering the Uncertainties on the Demands and Roughness Coefficients
Jung, Dong-Hwi ; Chung, Gun-Hui ; Kim, Joong-Hoon ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 73~80
The optimal design of water distribution system have started with the least cost design of single objective function using fixed hydraulic variables, eg. fixed water demand and pipe roughness. However, more adequate design is accomplished with considering uncertainties laid on water distribution system such as uncertain future water demands, resulting in successful estimation of real network's behaviors. So, many researchers have suggested a variety of approaches to consider uncertainties in water distribution system using uncertainties quantification methods and the optimal design of multi-objective function is also studied. This paper suggests the new approach of a multi-objective optimization seeking the minimum cost and maximum robustness of the network based on two uncertain variables, nodal demands and pipe roughness uncertainties. Total design procedure consists of two folds: least cost design and final optimal design under uncertainties. The uncertainties of demands and roughness are considered with Latin Hypercube sampling technique with beta probability density functions and multi-objective genetic algorithms (MOGA) is used for the optimization process. The suggested approach is tested in a case study of real network named the New York Tunnels and the applicability of new approach is checked. As the computation time passes, we can check that initial populations, one solution of solutions of multi-objective genetic algorithm, spread to lower right section on the solution space and yield Pareto Optimum solutions building Pareto Front.
Synthetic Streamflow Generation Using Autoregressive Modeling in the Upper Nakdong River Basin
Rubio, Christabel Jane P. ; Oh, Kuk-Ryul ; Ryu, Jae-H. ; Jeong, Sang-Man ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 81~88
The analysis and synthesis of various types of hydrologic variables such as precipitation, surface runoff, and discharge are usually required in planning and management of water resources. These hydrologic variables are mostly represented using stochastic models. One of which is the autoregressive model, that gives promising results in time series modeling. This study is an application of this model, which aimed to determine the AR model that best represents the historical monthly streamflow of the two gauging stations, namely Andong Dam and Imha Dam, both located in the upper Nakdong River Basin. AR(3) model was found to be the best model for both gauging stations. Parameters of the determined order of AR model (
) were also estimated. Using several diagnostic tests, the efficiency of the determined AR(3) model was tested. These tests indicated the accuracy of the determined AR(3) model.
Optimization of Multi-reservoir Operation considering Water Demand Uncertainty in the Han River Basin
Chung, Gun-Hui ; Ryu, Gwan-Hyeong ; Kim, Joong-Hoon ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 89~102
Future uncertainty on water demand caused by future climate condition and water consumption leads a difficulty to determine the reservoir operation rule for supplying sufficient water to users. It is, thus, important to operate reservoirs not only for distributing enough water to users using the limited water resources but also for preventing floods and drought under the unknown future condition. In this study, the reservoir storage is determined in the first stage when future condition is unknown, and then, water distribution to users and river stream is optimized using the available water resources from the first stage decision using 2-stage stochastic linear programming (2-SLP). The objective function is to minimize the difference between target and actual water storage in reservoirs and the water shortage in users and river stream. Hedging rule defined by a precaution against severe drought by restricting outflow when reservoir storage decreases below a target, is also applied in the reservoir operation rule for improving the model applicability to the real system. The developed model is applied in a system with five reservoirs in the Han River basin, Korea to optimize the multi-reservoir system under various future water demand scenarios. Three multi-purposed dams - Chungju, Hoengseong, and Soyanggang - are considered in the model. Gwangdong and Hwacheon dams are also considered in the system due to the large capacity of the reservoirs, but they are primarily for water supply and power generation, respectively. As a result, the water demand of users and river stream are satisfied in most cases. The reservoirs are operated successfully to store enough water during the wet season for preparing the coming drought and also for reducing downstream flood risk. The developed model can provide an effective guideline of multi-reservoir operation rules in the basin.
Application of a Non-Hydrostatic Pressure Model with Dynamic Boundary Condition to Free Surface Flow
Lee, Jin-Woo ; Jeong, Woo-Chang ; Cho, Yong-Sik ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 103~109
In this study, a three-dimensional non-hydrostatic pressure model based on a normalized vertical coordinate system for free surface flows is presented. To strongly couple the free surface and non-hydrostatic pressure with the momentum equations, a double predictor-corrector method is employed. The study is especially focused on implementing the dynamic boundary condition (a zero pressure condition) at the free surface with ignoring of the atmospheric pressure. It is shown that the boundary condition can be specified easily with a slight modification to existing models.
Numerical Simulation of Wave Deformation due to a Submerged Structure with a Second-order VOF Method
Ha, Tae-Min ; Cho, Yong-Sik ;
Journal of Korean Society of Hazard Mitigation, volume 10, issue 1, 2010, Pages 111~117
A three-dimensional numerical model is employed to investigate wave deformation due to a submerged structure. The three-dimensional numerical model solves the spatially averaged Navier-Stokes equations for two-phase flows. The LES(large-eddy-simulation) approach is adopted to model the turbulence effect by using the Smagorinsky SGS(sub-grid scale) closure model. The two-step projection method is employed in the numerical solutions, aided by the Bi-CGSTAB technique to solve the pressure Poisson equation for the filtered pressure field. The second-order accurate VOF(volume-of-fluid) method is used to track the distorted and broken free surface. A simple linear wave is generated on a constant depth and compared with analytical solutions. The model is then applied to study wave deformation due to a submerged structure and the predicted results are compared with available laboratory measurements.