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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Civil Engineers
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Journal DOI :
Korean Society of Civil Engeneers
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Volume & Issues
Volume 34, Issue 6 - Dec 2014
Volume 34, Issue 5 - Oct 2014
Volume 34, Issue 4 - Aug 2014
Volume 34, Issue 3 - Jun 2014
Volume 34, Issue 2 - Apr 2014
Volume 34, Issue 1 - Feb 2014
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Experimental Verification of Sag Sensitivities using Catenary Model for PPWS Configuration Control in a Suspension Bridge
Jeong, Woon ; Seo, Ju Won ; Lee, Sung Hyung ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 711~721
DOI : 10.12652/Ksce.2014.34.3.0711
PPWS, a large number of which a main cable of a suspension bridge consists of, must be precisely erected at a target location under construction considering the differences among design conditions. The absolute sag is measured for several PPWSs, which are reference strands and the relative sag is surveyed from them to other PPWSs, which are divided into several groups. And the adjustment of PPWS length is performed to erect it at target configuration. When PPWS is being under erection in a real bridge site, the procedures are as follows; evaluate sag sensitivities according to sag variation factors, calculate an adjustment length of PPWS corresponding to them and adjust a sag of PPWS by controlling the calculated amount of PPWS length. In this study, the differential-related equations of sag sensitivity were proposed for support movement of PPWS. Before site demonstration study of a series of them, we established a catenary model system and accomplished verification tests of them. From test results, the validation of them was done.
Validating Numerical Analysis Model Modeling Method by Polyhedral Rubble Mound Structure Arrays
Choi, Woong-Sik ; Kim, Kee-Dong ; Han, Tong-Seok ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 723~728
DOI : 10.12652/Ksce.2014.34.3.0723
Hydraulic experiments are performed in order to verify the swash effect of seashore structures installed to prevent scouring. However, a great deal of investment and time are required for producing the test apparatus and seashore structure used to perform the hydraulic experiment. The swash effect can be predicted, however, by using a numerical model and validation can be done based on comparisons of the numerical model and hydraulic experiment analysis results, thereby saving the cost and time required for producing the test apparatus and seashore structure. Taking a polyhedral rubble mound structure as the subject, this study performed a comparative analysis of wave run-up and run-down height of the numerical model interpretative results and the hydraulic experiment results, and validated the interpretative simulation wave test modeling technique. The study also predicted the swash effect by using the numerical interpretation approach method, whereby the volume ratio and friction area of the rubble mound were varied for different results.
Performance Evaluation of Seismic Vibration Control of Asymmetrical Cable-Stayed Bridge Using MR Damper
Heo, Gwanghee ; Kim, Chunggil ; Gong, Yeong I ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 729~737
DOI : 10.12652/Ksce.2014.34.3.0729
A study has been carried out that effectively controls the vibration of asymmetric cable-stayed bridges caused by earthquakes with MR dampers. In order to enhance the practical serviceability of MR dampers, an asymmetric cable-stayed bridge structure has been designed and produced, and a MR damper has been produced so as to have this bridge structure controlled appropriately. An experiment that controls vertical and horizontal vibrations has been carried out by exciting the asymmetric cable-stayed bridge in the horizontal direction with the El-centro seismic wave. The control performance of the MR damper has been evaluated under the five control conditions in the experiments of vibration control in each direction. As a result of the experiment, MR dampers were proved to control vibrations more effectively when either Lyapunov control algorithm or Clipped-optimal control algorithm was used to control vibrations of the asymmetric cable-stayed bridge caused by earthquakes. In addition, different controlling effects were found in vibration controls in vertical and horizontal directions due to the asymmetry of the structure and the horizontal excitation. With such controlling effects, semi-active MR dampers are evaluated to effectively control vibrations caused by earthquakes in flexible and asymmetric structures such as asymmetric cable-stayed bridges.
Connection Tests for Cold-Formed Steel Wall Panels
Lee, Young-Ki ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 739~746
DOI : 10.12652/Ksce.2014.34.3.0739
The objective of this test series was to determine shear load per unit length which causes a unit slip in the fastener joint. The shear load is one of major factors which reflect partial composite action for cold-formed steel wall stud panels. Test method used were based on the methods presented in the 1962 AISI Specification. According to the comparison with experimental strength, it is seen that the shear loads used in nominal axial strength predictions made acceptable results.
New Statistical Pattern Recognition Technology for Condition Assessment of Cable-stayed Bridge on Earthquake Load
Heo, Gwanghee ; Kim, Chunggil ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 747~754
DOI : 10.12652/Ksce.2014.34.3.0747
In spite of its usefulness for health monitoring of structures on steady external load, the statistical pattern recognition technology (SPRT), based on Mahalanobis distance theory (MDT), is not good enough for the health monitoring of structures on large variability external load like earthquake. Damage is usually determined by the difference between the average measured value of undamaged structure and the measure value of damaged one. So when external variability gets larger, the difference gets bigger along, which is thus easily mistaken for a damage. This paper aims to overcome the problem and develop an improved Mahalanobis distance theory (IMDT), that is, a SPRT with revised MDT in order to decrease external variability so that we will be able to continue to monitor the structure on uncertain external variability. This method is experimentally tested to see if it precisely evaluates the health of a cable-stayed bridge on each general random load and earthquake load. As a result, the IMDT is found to be valid in locating structural damage made by damaged cables by means of data from undamaged cables. So it is proved to be effectively applicable to the health monitoring of bridges on external load of variability.
Incremental Model Formulation of Creep under Time-varying Stress History
Park, Yeong-Seong ; Shin, Dong-Hun ; Lee, Yong-Hak ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 755~761
DOI : 10.12652/Ksce.2014.34.3.0755
Internal or external restraint of concrete strain due to drying shrinkage and creep in concrete structures causes mechanical strain and becomes a source of persistent change in creep-causing stress conditions. Mathematical modeling to incorporate the persistent change of creep-inducing stress is generally achieved with consideration of the ages of concrete and concrete properties at the times of loadings, and stress history. This paper presents an incremental format of creep model based on parallel creep concept to depict the creep under time-varying stress history in developing creep strain. Laboratory experiments are carried out to validate the performance of the presented creep model. Typical creep phenomena are addressed through the comparisons between the measured and predicted creep strains.
Physical Properties of Sulfur Concrete with Modified Sulfur Binder
Bae, Sung Geun ; Gwon, Seong Woo ; Kim, Se Won ; Cha, Soo Won ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 763~771
DOI : 10.12652/Ksce.2014.34.3.0763
Recently, a huge amount of sulfur has been produced as a byproduct of petroleum refining processes in Korea. Sulfur concrete is made of modified sulfur binder instead of cement paste, which has advantages of reducing
emission from cement industry as well as utilizing surplus sulfur. Also, sulfur concrete is a sustainable material that can be repetitively recycled. In this study, the physical properties of sulfur concrete are experimentally investigated. From the test results, sulfur concrete showed compressive strengths higher than at least 50MPa. Also, the unit weight, modulus of elasticity and splitting tensile strength of sulfur concrete was similar to that of Portland cement concrete (PCC). The coefficient of thermal expansion of sulfur concrete was a little larger than that of Portland cement concrete and sulfur concrete with mineral filler is helpful to lower the coefficient of thermal expansion. recycled aggregate sulfur concrete resulted in a slight reduction in the compressive strength, but sulfur concrete with recycled aggregate can achieve the high strength characteristics.
Evaluation of the Applicability of the Poisson Cluster Rainfall Generation Model for Modeling Extreme Hydrological Events
Kim, Dong-Kyun ; Kwon, Hyun-Han ; Hwang, Seok Hwan ; Kim, Tae-Woong ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 773~784
DOI : 10.12652/Ksce.2014.34.3.0773
This study evaluated the applicability of the Modified Bartlett-Lewis Rectangular Pulse (MBLRP) rainfall generation model for modeling extreme rainfalls and floods in Korean Peninsula. Firstly, using the ISPSO (Isolated Species Particle Swarm Optimization) method, the parameters of the MBLRP model were estimated at the 61 ASOS (Automatic Surface Observation System) rain gauges located across Korean Peninsula. Then, the synthetic rainfall time series with the length of 100 years were generated using the MBLRP model for each of the rain gauges. Finally, design rainfalls and design floods with various recurrence intervals were estimated based on the generated synthetic rainfall time series, which were compared to the values based on the observed rainfall time series. The results of the comparison indicate that the design rainfalls based on the synthetic rainfall time series were smaller than the ones based on the observation by 20% to 42%. The amount of underestimation increased with the increase of return period. In case of the design floods, the degree of underestimation was 31% to 50%, which increases along with the return period of flood and the curve number of basin.
Analysis of Watershed Hydrologic Responses using Hydrologic Index
Park, Yoonkyung ; Kim, Sangdan ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 785~794
DOI : 10.12652/Ksce.2014.34.3.0785
Hydrologic responses in watershed are determined by complex interactions among climate, land use, soil and vegetation. In order to effectively investigate hydrologic response in watershed, one needs to analyze the characteristics of climate as well as other factors. In this study, the relative contribution of climate factors and watershed characteristics on hydrologic response is investigated by using hydrologic indexes such as the aridity index and the Horton index. From preliminary analysis, it is shown that the Horton index is proper in terms of classifying hydrologic responses in main natural watersheds of south Korea. While climate and watershed characteristics both contributes to hydrologic responses, the degree contributed from each factor is changed depending on annual climatic humid conditions. In dry conditions, the climate factor is the predominant influence on hydrologic responses. However, in wet conditions, the contribution of watershed characteristics on hydrologic responses is relatively increased.
Prediction of Andong Reservoir Inflow Using Ensemble Technique
Kang, Min Suk ; Yu, Myungsu ; Yi, Jaeeung ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 795~804
DOI : 10.12652/Ksce.2014.34.3.0795
In this study, Andong Reservoir monthly and ten days inflows from July 2011 to September 2011 are predicted using SWAT model and ensemble technique. The weight method using monthly and ten days rainfall forecasts from Korea Meteorological Administration is applied for accurate analysis. If the rainfall prediction announced by Korea Meteorological Administration is close to the actual rainfall, the PDF-Ratio Method shows the best result. If the past high rainfall occurrence is close to the actual rainfall, the modified PDF-Ratio method shows the best result. This method can improve the prediction accuracy even though the Korea Meteorological Administration forecast is not accurate. On the contrary, if Korea Meteorological Administration forecast is different from the actual rainfall and the past rainfall occurrence statistics of lower section, the uniform method shows the best result.
Physical Habitat Simulation Considering Stream Morphology Change due to Flood
Lee, Sungjin ; Kim, Seung Ki ; Choi, Sung-Uk ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 805~812
DOI : 10.12652/Ksce.2014.34.3.0805
This study investigates the impact of morphological change on the physical habitat simulation. For this, CCHE2D model is used for the hydraulic analysis including the morphological change, and the physical habitat suitability is assessed with habitat suitability curves. The model is applied to a 2.5km long reach downstream of the Goesan Dam, from Sujeon Bridge to Daesu Weir. Flow data of discharge and stage in July, 2006 are used in the computation. The numerical model is verified by means of comparison with the measured water surface elevation data, and the variation of the river bed is not verified in this study. Adult Zacco platypus is chosen for the dominant species. Physical habitat simulations result in composite habitat suitability and weighted usable area for drought, low, normal, and averaged-wet flows. The simulation results indicate that the composite suitability index increased at reaches right downstream of the Sujeon Bridge and around the bend. This also increased weighted usable area by 5.4-11.3%.
Numerical Simulation of Mean Flows and Turbulent Structures of Partly-Vegetated Open-Channel Flows using the Nonlinear k-ε Model
Choi, Seongwook ; Choi, Sung-Uk ; Kim, Taejoon ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 813~820
DOI : 10.12652/Ksce.2014.34.3.0813
This study presents a numerical modeling of mean flow and turbulence structures of partly-vegetated open-channel flows. For this, Reynolds-averaged Navier-Stokes equations with vegetation drag terms are solved numerically using the non-linear k-
model. The numerical model is applied to laboratory experiments of Nezu and Onitsuka (2001), and simulated results are compared with data from measurement and computations by Kang and Choi's (2006) Reynolds stress model. The simulation results indicate that the proposed numerical model simulates the mean flow well. Twin vortices are found to be generated at the interface between vegetated and non-vegetated zones, where turbulence intensity and Reynolds stress show their maximums. The model simulates the pattern of the Reynolds stress well but under-predicts the intensity of Reynolds stress slightly.
A Development of Hourly Rainfall Simulation Technique Based on Bayesian MBLRP Model
Kim, Jang Gyeong ; Kwon, Hyun Han ; Kim, Dong Kyun ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 821~831
DOI : 10.12652/Ksce.2014.34.3.0821
Stochastic rainfall generators or stochastic simulation have been widely employed to generate synthetic rainfall sequences which can be used in hydrologic models as inputs. The calibration of Poisson cluster stochastic rainfall generator (e.g. Modified Bartlett-Lewis Rectangular Pulse, MBLRP) is seriously affected by local minima that is usually estimated from the local optimization algorithm. In this regard, global optimization techniques such as particle swarm optimization and shuffled complex evolution algorithm have been proposed to better estimate the parameters. Although the global search algorithm is designed to avoid the local minima, reliable parameter estimation of MBLRP model is not always feasible especially in a limited parameter space. In addition, uncertainty associated with parameters in the MBLRP rainfall generator has not been properly addressed yet. In this sense, this study aims to develop and test a Bayesian model based parameter estimation method for the MBLRP rainfall generator that allow us to derive the posterior distribution of the model parameters. It was found that the HBM based MBLRP model showed better performance in terms of reproducing rainfall statistic and underlying distribution of hourly rainfall series.
Large Eddy Simulation of Rectangular Open-Channel Flow using OpenFOAM
Ban, Chaewoong ; Choi, Sung-Uk ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 833~840
DOI : 10.12652/Ksce.2014.34.3.0833
This study presents numerical simulation of turbulent flows in a rectangular open-channel that has a width-to-depth ratio of 2 using the source code provided by OpenFOAM. Large eddy simulations are carried out by solving the filtered continuity and momentum equations numerically. For the non-isotropic residual stress term, Smagorinsky's (1963) model is used. The flow in the open-channel whose width-to-depth ratio is 2, from experiment of Tominaga et al. (1989), is simulated numerically. Simulation results are compared with measured data by Tominga et al. (1989) and Nezu and Rodi (1985) and with LES data by Shi et al. (1999). Comparisons revealed that the model simulates the mean flow and turbulence statistics well. Specifically, the model reproduced the inner secondary currents located at the corner of sidewall and free surface successfully. In addition, the vortical component of turbulence intensity shows bulged contours towards the bottom edge.
Flood Simulation for Basin-Shaped Urban Watershed Considering Surface Flow
Ahn, Jeonghwan ; Cho, Woncheol ; Jung, Jaehee ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 841~847
DOI : 10.12652/Ksce.2014.34.3.0841
Urban runoff models have been continuously developing with concerns for urban flood. Recently, models that be able to quantitatively analyze surface inundation caused by overflowed water from storm sewer were also developed by coupling 1-dimensional sewer model and 2-dimensional surface flow model. However, only overflowed water from storm sewer can be analyzed by the models have been developed until now. They are limited to be not able to analyze surface inundation caused by surface runoff that could not flow into the storm sewer. In order to overcome the limitation, basin-overlap method was devised adding a dummy 1-dimensional sewer layer to the model, so it can consider the efficiency of inflow to the storm sewer system. XP-SWMM 2011 is applied for urban runoff model and the flood event occurred on July 27, 2011 in basin-shaped Sadangcheon watershed is chosen for study inundation event. According to simulation results basin-overlap method reappear the observed inundation event more precisely than traditional method. This results suggest that drainage system has to be improved for reducing inundation caused by surface runoff and would be used as considerations for planning an urban basin design magnitude.
Re-establishing the Antecedent Moisture Condition of NRCS-CN Method Considering Rainfall-Runoff Characteristics in Watershed Based on Antecedent 5-Day Rainfall
Yoo, Ji-Young ; Moon, Geon-Woo ; Ahn, Jae-Hyun ; Kim, Tae-Woong ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 849~858
DOI : 10.12652/Ksce.2014.34.3.0849
The mount of antecedent 5-day rainfall (P5) is usually used to determine the antecedent soil moisture condition for estimating effective rainfall using the NRCS-CN method. In order to re-establish the threshold of P5 considering basin characteristics, this study investigated the sensitivity of the threshold of P5 to effective rainfall by comparing the corresponding observed direct runoff. The overall results indicate that the direct runoff estimated using the re-establihed threshold of P5 has smaller mean error (RMSE of 27.3 mm) than those using the conventional threshold (RMSE of 35.2 mm). In addition, after evaluating the effectiveness of threshold of P5 using the improvement index, the threshold re-established in this study improved the ability to estimate the direct runoff by 30% on average. This study also suggested to employ regression models using topographic indices to re-establish the threshold for ungauged basins. When using the re-established threshold from the regression model, the RMSE decreased ranging from 0.4 mm to 15.1 mm and the efficiency index of Nash and Sutcliffe increased up to 0.33.
Development of 3-D Hydrodynamical Model for Understanding Numerical Analysis of Density Current due to Salinity and Temperature and its Verification
Lee, Woo-Dong ; Hur, Dong-Soo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 859~871
DOI : 10.12652/Ksce.2014.34.3.0859
In order to analyze the density current due to salt and temperature difference, this study develops new numerical model (LES-WASS-3D ver. 2.0) by introducing state equation for salt and temperature and 3D advection-diffusion equation to existing 3D numerical wave tank (LES-WASS-3D ver. 1.0). To verify the applicability, the newly-developed numerical model is analyzed comparing to the experimental result of existing numerical model. In the result, it well implement the behavior and vertical salt concentration of advected and diffused seawater as well as flow velocity and temperature of the discharged warm water. This confirms the validity and effectiveness of the developed numerical model.
A Study on Estimation of Allowable Wave Height for Loading and Unloading of the Ship Considering Ship Motion
Kwak, Moon Su ; Moon, Yong Ho ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 873~883
DOI : 10.12652/Ksce.2014.34.3.0873
This study proposed an estimation method of allowable wave height for loading and unloading of the ship considering ship motion that is affected by ship sizes, mooring conditions, wave periods and directions. The method was examined validity by comparison with wave field data at pier
in Pohang new harbor. The wave field data obtained with wave height of 0.10~0.75m and wave period of 7~13s in ship sizes of 800~35,000ton when a downtimes have occurred. On the other hand, the results of allowable wave height for loading and unloading of the ship in this method have obtained with wave heights of 0.19~0.50m and wave periods of 8~12s for ship sizes of 5,000, 10,000 and 30,000ton. Thus this method well reproduced the field data respond to various a ship sizes and wave periods. And the results of this method tended to decrease in 16~62% when have considered long wave, and it is decreased in 0~46% when didn't consider long wave than design standards in case of the ship sizes of 5,000~30,000ton, wave period of 12s and wave angle of
. The allowable wave heights for loading and unloading of the ship proposed by design standards are didn't respond to various the ship sizes and wave periods, and we have found that the design standards has overestimated on smaller than 10,000ton.
The Remediation Characteristic of Soil Contaminated with Heavy Metal and Total Petroleum Hydrocarbon (TPH) by Enhanced Electrokinetic with Fenton Oxidation and Soil Flushing Method
Seo, Seok-Ju ; Na, So-Jeong ; Kim, Jung-Hwan ; Park, Joo-Yang ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 885~893
DOI : 10.12652/Ksce.2014.34.3.0885
This research reports the enhanced Electrokinetic (EK) with
and sodium dodecyl surfate (SDS), which are commonly used in Fenton oxidation and soil flushing method, in order to remediate soil contaminated with heavy metals and Total Petroleum Hydrocarbons (TPH) simultaneously. In addition, influences of property of soil and concentration of chemical solution were investigated through experiments of different types of soils and varying concentration of chemical reagents. The results indicated, in the experiments using artificially contaminated soil, the highest removal efficiency of heavy metals using 10%
and 20mM SDS as electrolytes. However, in the experiments using Yong-San soils (study area), remediation efficiency of heavy metals was decreased because high acid buffering capacity. Through experiment of 20%
and 40mM SDS, increased electric current influences the remediation of heavy metals due to decrease in the soil pH. In the experiments of Yong-San soils, the remediation efficiency of TPH was decreased compared with artificially spiked soils because high acid buffering capacity and organic carbon contents. Furthermore, the scavenger effect of SDS influenced TPH oxidation efficiency under the conditions of injected 40mM SDS in the soils. Therefore, the property of soil and concentration of chemical reagents cause the electroosmotic flow, soil pH, remediation efficiency of heavy metals and TPH.
Analysis of Dynamically Penetrating Anchor based on Coupled Eulerian-Lagrangian (CEL) Method
Kim, Youngho ; Jeong, Sang-Seom ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 895~906
DOI : 10.12652/Ksce.2014.34.3.0895
A fundamental study of the dynamically penetrating anchor (DPA - colloquially known as torpedo anchor) embedded into deep seabed was conducted using measurement data and numerical approaches. Numerical simulation of such a structure penetration was often suffered by severe mesh distortion arising from very large soil deformation, complex contact condition and nonlinear soil behavior. In recent years, a Coupled Eulerian-Lagrangian method (CEL) has been used to solve geomechanical boundary value problems involving large deformations. In this study, 3D finite element analyses using the CEL formulation are carried out to simulate the construction process of dynamic anchors. Through comparisons with results of field measurements, the CEL method in the present study is in good agreement with the general trend observed by in-situ measurements and thus, predicts a realistic large deformation movement for the dynamic anchors by free-fall dropping, which the conventional FE method cannot. Additionally, the appropriate parametric studies needed for verifying the characteristic of dynamic anchor are also discussed.
Model Test of Stabilizing Measures for Ground Failure Due to Soft Ground Excavation
Kim, Jae-Hong ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 907~917
DOI : 10.12652/Ksce.2014.34.3.0907
When conducting excavations after burying the soft ground, even if the retaining walls are installed, failure often occurs within backfill. In order to minimize the occurrences of failures, model test was performed after the installation of stabilizing piles to investigate the stabilizing effects. The model chamber is set up with clay foundation reinforced with and without stabilizing piles. During the excavation of clay foundation, the subsidence, pore water pressure, and soil pressure along the excavation were measured. As a result of the model test, the increase of excavation levels and the reduction of subsidence of back ground were observed with the stabilizing piles, compared to those without the stabilizing piles. The installation of stabilizing piles does not influence the pore water pressure change, but induces less subsidence rate. In addition, the depth of excavation has a significant effect on the back ground and it was evaluated that the maximum subsidence occurs as it is closer to the excavation point.
Numerical Study on Shotcrete Lining with Steel Reinforcement Using a Fiber Section Element
Kim, Jeong Soo ; Yu, Jee Hwan ; Kim, Moon Kyum ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 919~930
DOI : 10.12652/Ksce.2014.34.3.0919
In this study, the load capacities and behaviors of a shotcrete member with steel supports, as composite member, are investigated numerically by using a fiber section element. The cross section of a shotcrete lining with steel support is divided into a bundle of fibers, which are allocated nonlinear stress-strain relations and used for determining internal forces. To verify the used approach of the finite element method for shotcrete with steel supports, the load-displacement relations of shotcrete lining obtained by numerical analysis are compared with existing experimental results and are analyzed with the stress distribution of the shotcrete and steel support obtained numerically. As a result, it is shown that the proposed approach can predict the load capacities of each material and the overall nonlinear behavior of shotcrete lining with steel supports. The change of location of the neutral axis and the flexural resistance ratio of each material are also derived from the stress distribution of the cross section of the shotcrete lining with steel supports. From the results, it is concluded that the flexural resistance performance of steel support should be considered in shotcrete lining design.
A Study on Assessment Indicator of Walking Environment Considering Land Use Characteristics
Kim, Suk Hee ; Lee, Kyu Jin ; Choi, Keechoo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 931~938
DOI : 10.12652/Ksce.2014.34.3.0931
This study presents a systematic method of evaluation with the premise that satisfaction rating scale of the walking environment will vary according to the characteristics of land use by footpath types. Ultimately, it aims to contribute to the effective management and improvement of footpaths. The result of the study shows a statistically significant difference in the indicators and it's weights for walking environment on new town, old town, commercial areas, subway station, river and park by footpath types. After applying the walking environment assessment model to some of the footpaths in Suwon, it was found that actual level can be simulated successfully in reality. Therefore, the result of the study is expected to help determining the priorities for the walking environment improvement for the local government.
Importance Factor Analysis on Mobility Facilities for the Transportation Disabled by Using Structural Equation Model
Ahn, Woo-Young ; Choi, Lee-Ra ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 939~945
DOI : 10.12652/Ksce.2014.34.3.0939
In most of mobility enhancing plans for the transportation disabled, decisions for the investment priorities are firstly made by the facilities that have lower installation rate or lower satisfaction rate; the decisions are made without analyzing the importance factor (path loading factor) between the facility installation rate and the satisfaction rate together. In this study, a novel method of finding causality between the exogenous latent variables and the endogenous latent variables is provided by using the Structural Equation Model (SEM). The results show that the most influential facilities for the transportation disabled are bus stops, crosswalks and sidewalks in order. Also, a curb height around bus stops, a smoothness of sidewalks and installation of crosswalks traffic light are identified as an important facilities for the Transportation disabled.
Development of Failure Criterion of Hot Mix Asphalt Using Triaxial Shear Strength Test
Kim, Seong Kyum ; Lee, Kwan Ho ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 947~954
DOI : 10.12652/Ksce.2014.34.3.0947
In general, Fracture of the material is not occurring of the maximum normal stress or the maximum shear stress failure in the state. Maximum normal stress and maximum shear stress in the state of Critical coupling from being destroyed based on the Mohr-Coulomb theory. Couple of different mixtures, including permeable asphalt pavement, SMA and dense-graded asphalt mixture, were used for compression triaxial test at
. Mohr-Coulomb theory to the analysis of compression triaxial test result of the internal friction angle
measured somewhat irregularly, but in the case of cohesion, depending on whether the temperature and immersion of the specimen appeared differently. In addition, Indirect tensile test and compression triaxial test of the asphalt mixture to determine the correlation between compression triaxial test results assessed as cohesion and internal friction angle calculated using the theoretical Indirect tensile strength and measured indirectly tensile strength were analyzed. The Measured & Predicted IDT St values tended to be proportional.
A Study on Building a Negotiation Framework to Resolve Conflicts from Constructing New Roads or Expanding Existing Roads
Hwang, Kyung-Soo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 955~963
DOI : 10.12652/Ksce.2014.34.3.0955
The objective of this study is to identify ways to resolve conflicts arising from building new roads or expanding existing roads by introducing negotiation techniques to the Jeju government. A case of city planning (Jungjeong-ro, Seogwipo City, Jeju Special Self-Governing Province) was analyzed in this study in an aspect of negotiation. In the case, the Committee for Promoting and Vitalizing Jungjeong-ro conducted negotiations from February, 2011 to December, 2011. This study proposes ways to establish systems which resolve problems during negotiation processes and frame concepts related to negotiation in the overall administrative systems. Firstly, setting up a negotiation management team within the provincial office and supporting it fully is needed. Secondly, there should be a process in which decisions made by the negotiation team become authoritative. Thirdly, for smooth negotiation processes, it is necessary to formulate ground rules and make negotiating parties obey them thoroughly. Fourthly, a negotiation clinic team should be established at the Jeju provincial government. Fifthly, there should be a negotiation school within the framework of human resources development. Sixthly, If officials do their negotiation jobs positively, a reward system should be established to give them adequate rewards. Lastly, concept of negotiation should take root in administration in general.
Development and Field Application of Portable Tensioning System Using Segmental CFT Member
Lee, Doo Sung ; Kim, Tae Kyun ; Lee, Sung Chul ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 965~975
DOI : 10.12652/Ksce.2014.34.3.0965
Pretension PSC (Prestressed Concrete) members are subjected to a certain limit of size as they are generally produced in the off-site plant and transferred to the site due to the large scale of the product on system. In this study, a portable pretensioning production system has been developed, which allow us to apply the pretension method on site. Considering that a 50m span PSC girder using the pretension method requires a pressing device to endure a large jacking force, the portable pretension production system has to ensure safety against such a large pretension jacking force. In this study, the portable pretensioning system to produce a 50m span pretension girder was manufactured by using CFT (Concrete Filled steel Tube) members. In order to understand the stability of the system and the behavior of the elements, a static loading test was conducted and the stability of the proposed portable pretensioning production system was confirmed. The developed portable pretension system was applied to several construction sites and was investigated the problems on site. During the pretension girder and slab members that was producted by this pretension system in construction site, it has be found the several advantages such as simple fabrication processes, reduction of prestress-loss, and a decrease of 15% compared with the fabrcation cost of post-tension girder. After due consideration of the problems, this portable pretension system will be improved.
Development of Evaluation System for Overseas Business Capability of Construction Firms
Jang, Woosik ; Yang, Hae-Beom ; Han, Seung-Heon ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 977~987
DOI : 10.12652/Ksce.2014.34.3.0977
Since 1960's, international construction market have explosively increase and have reached up to 600 Bil. US$ through active participation of construction firms and steady support of government. Nevertheless, owners, clients and financial institutions required reasonable criteria to effectively assess the overseas business capabilities of construction firms. However, the existing methods for construction firms rarely considers the perspective of overseas business capabilities. To overcome these problems, this study proposes an evaluation system for overseas business capabilities of construction firms. First, the needs for new evaluation system is derived through FGI, and the direction of new evaluation system is presented by reviewing the limitations of existing methods. Also, the capabilities that are required for the performances for overseas businesses were analyzed through expert interviews. Finally, 31 primary evaluation indices consisting of 3 criteria - appropriateness of index, possibility of quantification, possibility of data gathering - are derived under 9 categories and 3 perspectives through surveys and consultation meeting. The preliminary investigation of 24 Korean construction firms are conducted for comparing the existing evaluation systems and to verify its applicability. The proposed method could provide a rational criterion to evaluate the construction firms, improve internal capacity of firms, and ultimately supports the success of the construction industry.
Priority Analysis for Infrastructure Recovery from Volcanic Disaster
Park, Hyung Keun ; Kang, Kyo Seok ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 989~998
DOI : 10.12652/Ksce.2014.34.3.0989
Recently volcanic eruptions and activities occurring in many parts of world have become a common global concern to many countries. The severity of these Volcanic disasters, such as of Mt. Eyjafjallajokull in Iceland and Mt. Merapi in Indonesia, have caused damages and causalities reaching astronomical levels. The infrastructure is categorized into 18sections that appropriately reflecting the survey data collected from various government agents, current inhabitant and engineers to accumulate a database on the priorities and preferences of restoring and reconstructing many kinds of infrastructure and facilities. The survey data was collect by using the "Likert 5 Scale Method" which emphasized the importance and priority of reconstruction and restoration for the specific facilities and infrastructures. The data was corrugated, organized and used in plotting and planning a strategic recovery agenda. The survey results were analyzed and verified to ensure the validity and reliability of the data by using chi-square test. This paper presents that recovery period and recovery cost to the total damage of infrastructure and facilities were used to make a recovery network with implemented construction management method. The research is expected that a more efficient and prompt recovery protocol and recovery plan can be executed and can be use as a reference and database.
A Study on CO
Emission Factor for Earth-Work Equipment Using C-FVM
Kim, Byung-Soo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 999~1006
DOI : 10.12652/Ksce.2014.34.3.0999
emission factor for earthwork equipment was made based on fuel consumption quantity using IPCC carbon emission factor. This is presented through the carbon emission estimating guideline each facilities by the Ministry of Land, Infrastructure and Transportation in 2011. However, this method has the defect which don't apply the various condition of site. Therefor it needs the new emission factor supplemented these defects. This study will tries to estimate
emission with the direct measurement method using concentration flow velocity measurement (C-FVM) for earth work equipment and present the new
emission factor for earth work equipment after compare with emission factor of the Ministry of Land, Infrastructure and Transportation.
Development of a Computer System and Suggestion of Man-Hours for Demolition Cost Estimation
Kim, Hyo Jin ; Kang, Leen Seok ; Lee, Dong Wook ; Kim, Chang Hak ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 1007~1015
DOI : 10.12652/Ksce.2014.34.3.1007
The importance of construction waste reusing and recycling is becoming increasingly large because the demolition industry is in current trend to pursue for sustainable growth. As the considering situation of the domestic housing construction and existing house, a scale of demolition industry is expected to be increased continuously. But the related cost regulations that are used in tendering in the demolition industry are insufficient, also the computer system for estimating the demolition costs have not been developed yet. Therefore, in this study suggests man-hours of 21EA items which are utilized to estimate demolition cost and work rate of
breaker which is used mostly in domestic demolition industry after analyzing a case study for deconstruction works. The computer system is developed for the estimating demolition cost easily, which are including five modules such as a project information, a unit cost management, a standard unit cost table, a bill of quantity, and a reporting system. This computer system is possible to apply for estimating cost of both mechanical demolition and blasting demolition. The biggest advantage of this system is to estimate cost to utilize standard WBS which is linked with standard unit table and each DB. This can help unskilled users use easily for it.
A Factor Analysis of Urban Railway Casualty Accidents and Establishment of Preventive Response Systems
Kim, Si Gon ; Park, Il Ha ; Oh, Jae Kyung ; Kim, Yeon Kyu ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 1017~1022
DOI : 10.12652/Ksce.2014.34.3.1017
Since the opening of Seoul Subway Line #1 in 1974, the number of passengers has been increasing. The possibility for passenger's accidents in railway stations has also increased. In order to decrease these kind of accidents, railway operation systems have been automated. Nevertheless, the possibility of a casualty accident in railway stations remains. This study analyzed the type of casualty accidents, casualty accidents by age, sex, pedestrian facility, and passenger type based on the internal data of Seoul Metro. The causes of casualty accidents are also found out. Finally, the establishment of railway safety education program and railway safety experience center are suggested in order to prevent the urban railway casualty accident in advance at railway stations.
A Study on the Effectiveness of Supply and Evaluation of Residential Intention for Long-term Secured Public Rental Housing
Lee, Youn Soo ; Ryu, Hoon ; Park, Sung Jin ; Kang, Jun Mo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 1023~1031
DOI : 10.12652/Ksce.2014.34.3.1023
This study is conducted to evaluate the supply effectiveness of the Long-term Secured Public Rental Housing (LSPRH) program implemented by the City of Seoul since March, 2012. To estimate the residential intention of potential applicants for the housing program, two logistic regression models of residential intention are estimated based on the residential characteristics of real residents. The purpose of this model estimation is to find out factors influencing the supply of LSPRH and thus to suggest the ideas for improving the effectiveness of the rental housing program operation. The analysis result shows that financial condition, income level, and public support are the major determinants for selecting LSPRH. It is also revealed that those who are currently living in rental housing or living in a house more expensive than those in nearby areas have higher residential intention for the LSPRH program. The result also presents that some problems associated with the traditional rental housing programs - such as visually recognizable low-quality exterior building design or the concentration of rental housing on limited spots - could be solved by this new type of public housing program. Lastly, one interesting finding different from previous research is that people with the intention to move into either traditional rental housing or LSPRH do not necessarily prefer a more spacious house than their current rental house.
Urbanization and Urban Heat Island Analysis Using LANDSAT Imagery: Sejong City As a Case Study
Kim, Mi-Kyeong ; Kim, Sang-Pil ; Kim, Nam-Hoon ; Sohn, Hong-Gyoo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 3, 2014, Pages 1033~1041
DOI : 10.12652/Ksce.2014.34.3.1033
Rapid urbanization of Korea was an unprecedented example in the world and urban population increased significantly. As a result, unbalanced distribution of population is serious problem in Korea because approximately 50% of the population is concentrated in the capital area that is 10% of nation's territory, thereby occurring various urban problems including UHI. Hence, Sejong Special Autonomous City was inaugurated officially on 2 July 2012 in order to decentralize population of capital area and induce more balanced regional development. The Sejong City has been changed drastically over a period of years as developed practically since the late 2000's and is expected to have new problems of urbanization. The land cover change due to urbanization is the main cause of UHI that urban area is significantly warmer than its surrounding areas and UHI is not only affecting urban climate change but also natural environment. So the purpose of this research is to analyze level of urbanization and UHI effect and to provide the correlation analysis between Land Surface Temperature and spectral indices. To achieve this, satellite imagery from LANDSAT were used. NDVI, NDBI, and UI were calculated using red, near-infrared, mid-infrared (
) images and LST was retrieved utilizing thermal infrared (
) image. Based on each index and LST, Changes of NDVI, UI and UHI through TVI were analyzed in Sejong City. UHI effect increased around newly constructed multi-functional administrative city, the correlation between LST and NDVI was negative and UI was strong positive.