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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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Korean Society of Civil Engeneers
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Volume & Issues
Volume 33, Issue 6 - Nov 2013
Volume 33, Issue 5 - Sep 2013
Volume 33, Issue 4 - Jul 2013
Volume 33, Issue 3 - May 2013
Volume 33, Issue 2 - Mar 2013
Volume 33, Issue 1 - Jan 2013
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Data Analysis and Health Index for Health Monitoring of Seohae Bridge
Kim, Hyunsu ; Kim, Yuhee ; Park, Jongchil ; Shin, Soobong ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 387~395
DOI : 10.12652/Ksce.2013.33.2.387
It is important to collect reliable measured data for proper bridge health monitoring. However, in reality incomplete and unreliable data may be acquired due to sensor problems and environmental effects. In case of sensor malfunction, parts of measured data are missing and thus health monitoring cannot be carried out reliably. Due to environmental effects such as temperature variation, dynamic characteristics of natural frequencies may change as if the structure is damaged. The paper proposes a systematic procedure of data processing and data analysis for reliable structural health monitoring. Also, it applies the Mahalanobis distance as a health index computed statistically using revised data. The proposed procedure has been examined using numerically simulated data from a truss structure and then applied to a set of field data measured from Seohae cable-stayed bridge.
Seismic Performance of Fabricated Internally Confined Hollow CFT Column
Won, Deok Hee ; Han, Taek Hee ; Kim, Seungjun ; Kang, Young Jong ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 397~407
DOI : 10.12652/Ksce.2013.33.2.397
Recently, a great progress has been made in bridge construction technology through the development of high performance materials and new structural types. However, most of attention has been paid to the cast-in-place technologies and material cost saving. The cast-in-place method is always subject to some environmental damages in construction sites, which frequently causes conflicts with residents. To overcome the disadvantages, a lot of fabrication construction method was developed. Most fabrication construction methods developed up to now have been applied for superstructure of bridges. In contrast, such fabricable methods developed for substructures are extremely rare. A fabricated column using ICH CFT(Internally Confined Hollow CFT) column was developed in a series of previous researches. Included in the previous studies are design and construction methods for the precast segmental coping, the column-coping connection, the column-segment connection, column-foundation connection. In this paper, seismic performance of the fabricated ICH CFT columns was extensively investigated experimentally. Two test specimens were prepared depending on the connection methods of segments; one by mortar-grouting method and the other by reinforcement method using stiffeners.
Stability and P-Δ Analysis of Generalized Frames with Movable Semi-Rigid Joints
Min, Byoung Cheol ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 409~422
DOI : 10.12652/Ksce.2013.33.2.409
For stability design and P-
analysis of steel frames with semi-rigid connections, the explicit form of the exact tangential stiffness matrix of a generalized semi-rigid frame element having rotational and translational connections is firstly derived using the stability functions. And its elastic and geometric stiffness matrix is consistently obtained by Taylor series expansion. Next depending on connection types of semi-rigidity, the corresponding tangential stiffness matrices are degenerated based on penalty method and static condensation technique. And then numerical procedures for determination of effective buckling lengths of generalized semi-rigid frames members and P-
and shortly addressed. Finally three numerical examples are presented to demonstrate the validity and accuracy of the proposed method. Particularly the minimum braced frames and coupled buckling modes of the corresponding frames are investigated.
Improved Method for Indeterminate forces of Two-span Steel-concrete Composite Girders
Ji, Gu Sam ; Kim, Choong Eon ; Shin, Dong Ki ; Choi, Dong Ho ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 423~431
DOI : 10.12652/Ksce.2013.33.2.423
The k-factor method has been widely used in design of steel-concrete composite bridges to determine indeterminate stresses. The accuracy of k-factor method is examined by a comparative analysis with the equivalent load method in a continuous 2-span composite bridge. To improve the accuracy, the direction of creep stress has to be modified and the variety of section must be considered. This paper suggests j-factor method which can improve the accuracy of k-factor method with simple modification.
Experimental Tests for the Evaluation of One-dimensional and Two-dimensional Acoustic Source Locations with 50m length of a PSC Box Girder
Youn, Seok-Goo ; Lee, Changno ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 433~442
DOI : 10.12652/Ksce.2013.33.2.433
This paper presents experimental research work for the evaluation of one-dimensional and two-dimensional acoustic source locations with 50m length of a precast prestressed concrete box girder. Acoustic events are generated by the impacts of Schmidt Hammer and the impact signals are detected by acoustic emission sensors mounted on the concrete web surface of PSC box girder with the average spacing of 9.34m. Based on the amplitude of detected acoustic signals, considering the noises developed in PSC box girder bridges, the arrival times of acoustic signals are estimated by the first arrival times of 0Volt, 0.5Volt, and 1.0Volt amplitude in each signal. Using Least Square Method, the velocities and the source locations of acoustic signals are evaluated. Based on the test results, the spacing of AE sensors and the AE sensor networks are discussed to reduce the source location errors.
Multi-DOF Real-time Hybrid Dynamic Test of a Steel Frame Structure
Kim, Sehoon ; Na, Okpin ; Kim, Sungil ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 443~453
DOI : 10.12652/Ksce.2013.33.2.443
The hybrid test is one of the most advanced test methods to predict the structural dynamic behavior with the interaction between a physical substructure and a numerical modeling in the hybrid control system. The purpose of this study is to perform the multi-directional dynamic test of a steel frame structure with the real-time hybrid system and to evaluate the validation of the results. In this study, FEAPH, nonlinear finite element analysis program for hybrid only, was developed and the hybrid control system was optimized. The inefficient computational time was improved with a fixed number iteration method and parallel computational techniques used in FEAPH. Furthermore, the previously used data communication method and the interface between a substructure and an analysis program were simplified in the control system. As the results, the total processing time in real-time hybrid test was shortened up to 10 times of actual measured seismic period. In order to verify the accuracy and validation of the hybrid system, the linear and nonlinear dynamic tests with a steel framed structure were carried out so that the trend of displacement responses was almost in accord with the numerical results. However, the maximum displacement responses had somewhat differences due to the analysis errors in material nonlinearities and the occurrence of permanent displacements. Therefore, if the proper material model and numerical algorithms are developed, the real-time hybrid system could be used to evaluate the structural dynamic behavior and would be an effective testing method as a substitute for a shaking table test.
Study on the Reinforced Concrete Slab Bridges of North Korea
Han, Eui Seok ; Lee, In Keun ; Park, Sun Kyu ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 455~464
DOI : 10.12652/Ksce.2013.33.2.455
If North Korea continuously remains an isolated nation without social interaction with South Korea, the gaps in the theoretical and technological status in construction technology become greater between North and South Korea. Therefore if interactions between North and South Korea can be made, there will be significant improvement in infrastructure technological performance can be made(i.e., Reinforced Concrete bridges). This study was performed to compare and analyze data related to the design standards of North Korean RC bridges and to execute a structural analysis based on standard design specifications of RC slab bridges. Especially, basic study of analyzing the influences on design truck loads of North and South Korea was conducted for the purpose of predicting the performance of North Korean RC slab bridges and the safety levels of traveling vehicles in advance. It is expected that the results of this study can be used as fundamental data for the set-up of South-North RC bridge specification when South and North Korea enter a stage of cooperation and interaction between South and North Korea are actively pursued to prepare for reunification.
Experimental Study on the Fire Proofing Characteristic of Fire Resistance Panel that it attaches to PSC Airpit-Slab
Lee, Doo Sung ; Bae, Jeong ; Choi, Heon ; Min, In Gi ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 465~473
DOI : 10.12652/Ksce.2013.33.2.465
In this Study, the performance of precast PSC slabs with fire resistance panel for fire resistance of the tunnel system was evaluated by experimentally. The fire test was performed in fire resistance (electric) furnace according to RABT(Richtlinien fur die Ausstatung und den Betrieb von stra
entunneln) time heating temperature curve. The test results showed that the measured temperatures at the t
Fundamental Properties of Fly ash Concrete Containing Lightly Burnt MgO Powder
Choi, Seul-Woo ; Jang, Bong-Seok ; Lee, Kwang-Myong ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 475~481
DOI : 10.12652/Ksce.2013.33.2.475
Although the lightly burnt MgO at
has expansibility, it does not lead to unsound concrete. The expansion of MgO could compensate for shrinkage of concrete for a long-term, because the hydration of MgO occurs at a slow pace. Recently, the study and application of mineral admixture such as fly ash and blast furnace slag have increased for the hydration heat reduction, durability improvement, and reducing
emission in the construction industry. Thus, it is necessary to research on the concrete that contains both a mineral admixture and MgO as an expansion agent. This study investigates fundamental properties of fly ash concrete with lightly burnt MgO through various experiments. The adiabatic temperature test results showed that the fly ash concrete with MgO of the 5% replacement ratio had the slower pace of the temperature rise and the lower final temperature than the fly ash concrete. The influences of MgO on long-term compressive strength varied depending on water-binder ratio, and the long-term length change test results indicated the expansion effects of the FA concrete containing MgO.
Predictions of Curvature Ductility Factor of Reinforced Concrete Beam Sections Used High Strength Concrete and Steel
Lee, Hyung Joon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 483~493
DOI : 10.12652/Ksce.2013.33.2.483
The high strength materials have been more widely used in a large reinforced concrete structures. It is known that the use of high strength material in RC structures give the benefits of the mechanical and durable properties, but the ductility decreases with an increase in the strength of the materials. In the design of a reinforced concrete beam, both the flexural strength and ductility need to be considered. So, it is necessary to assess accurately the ductility of the beam with high strength materials in order to ensure the ductility requirement in design. In this study, the effects of the material strength on the flexural behavior and curvature ductility factor of reinforcement concrete beam sections with various reinforcement conditions have been evaluated and a newly prediction formula for curvature ductility factor of RC beam has been developed considering the stress of compression reinforcement at ultimate state. The proposed predictions for the curvature ductility factor which is applicable to both singly and doubly reinforced concrete beam are verified by comparisons with other prediction formulas and the proposed formula offers fairly accurate within 9% error and consistent predictions for curvature ductility factor of reinforced concrete beam.
Time-split Mixing Model for Analysis of 2D Advection-Dispersion in Open Channels
Jung, Youngjai ; Seo, Il Won ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 495~506
DOI : 10.12652/Ksce.2013.33.2.495
This study developed the Time-split Mixing Model (TMM) which can represent the pollutant mixing process on a three-dimensional open channel through constructing the conceptual model based on Taylor`s assumption (1954) that the shear flow dispersion is the result of combination of shear advection and diffusion by turbulence. The developed model splits the 2-D mixing process into longitudinal mixing and transverse mixing, and it represents the 2-D advection-dispersion by the repetitive calculation of concentration separation by the vertical non-uniformity of flow velocity and then vertical mixing by turbulent diffusion sequentially. The simulation results indicated that the proposed model explains the effect of concentration overlapping by boundary walls, and the simulated concentration was in good agreement with the analytical solution of the 2-D advection-dispersion equation in Taylor period (Chatwin, 1970). The proposed model could explain the correlation between hydraulic factors and the dispersion coefficient to provide the physical insight about the dispersion behavior. The longitudinal dispersion coefficient calculated by the TMM varied with the mixing time unlike the constant value suggested by Elder (1959), whereas the transverse dispersion coefficient was similar with the coefficient evaluated by experiments of Sayre and Chang (1968), Fischer et al. (1979).
Assessment of Agricultural Water Supply Capacity Using MODSIM-DSS Coupled with SWAT
Ahn, So Ra ; Park, Geun Ae ; Kim, Seong Joon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 507~519
DOI : 10.12652/Ksce.2013.33.2.507
This study is to evaluate agricultural water supply capacity in Geum river basin (9,865
), one of the 5 big river basin of South Korea using MODSIM-DSS (MODified SIMyld-Decision Support System) model. The model is a generalized river basin decision support system and network flow model developed at Colorado State University designed specifically to meet the growing demands and pressures on river basin management. The model was established by dividing the basin into 14 subbasins and the irrigation facilities viz. agricultural reservoirs, pumping stations, diversions, culverts and groundwater wells were grouped and networked within each subbasin and networked between subbasins including municipal and industrial water supplies. To prepare the inflows to agricultural reservoirs and multipurpose dams, the Soil and Water Assessment Tool (SWAT) was calibrated using 6 years (2005-2010) observed dam inflow and storage data. By MODSIM run for 8 years from 2004 to 2011, the agricultural water shortage had occurred during the drought years of 2006, 2008, and 2009. The agricultural water shortage could be calculated as 282
, and 329
A Numerical Modeling of Surcharged Manhole Flow with the Consideration of the Energy Loss Coefficient
Kim, Kyoung Beom ; Kim, Jung Soo ; Yoon, Sei Eui ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 521~528
DOI : 10.12652/Ksce.2013.33.2.521
Urban drainage systems are generally designed as open channel flow. The system, however, shows a partially surcharged flow in its body, especially at junctions or manholes. Thus, a special case of this condition needs to be explained as pressurized flow condition for designing the sewer system. This study considered the surcharged manhole flows during an unexpected rainfall event or an excess of design frequency. Overflows from surcharged manholes and urban flooding can occur from the effect of surcharged flows. Thus, sewer systems should be designed with the concept of open channel flow and pressurized flow. Also, energy losses in a manhole need to be considered. The aim of this study is to develop the numerical model which can evaluate the effect of the energy losses at the manhole. The numerical model was verified and compared with hydraulic model and SWMM. The results showed that the water depth of numerical model was in good agreement with hydraulic model at the each manhole. However, the SWMM underestimated the water depth because that model ignored the energy losses at manholes. Thus, the developed numerical model in this study could be a useful tool for the assessment of a conveyance of urban drainage system.
Parameter Estimation of SWAT Model Using SWAT-CUP in Seom-river Experimental Watershed
Choi, Heung Sik ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 529~536
DOI : 10.12652/Ksce.2013.33.2.529
The semi-distributed rainfall runoff model of SWAT is applied to the Seom-river experimental watershed. The simulations of various antecedent periods before the targeted simulation periods of 2002 to 2009 are not necessary despite of the slight appearance of corresponding changes in simulated total runoff. The simulated results of total runoff by using various numbers of soil layer maps have little differentiated nevertheless the slight changes in simulated results have been appeared. The 7 parameters of CANMX,
, ESCO, GW_REVAP, SOL_ALB, SOL_AWC, and SOL_K greatly govern the rainfall runoff are confirmed and their sensitivity analyses have been carried out. The optimal parameters used in SWAT are derived by SUFI-2 of SWAT-CUP. The NS and
are 0.99 and 0.98, respectively which is shown the good agreement between the observed and the simulated results. The uncertainty factors of P-factor and R-factor are 0.85 and 0.06, respectively which is also shown the high efficiency of the model. The high applicability is also shown with improving the RMSE in SWAT model simulation using the parameters estimated by SUFI-2 of SWAT-CUP.
Effect of Chungju Dam Operation for Flood Control in the Upper Han River
Kim, Sang Ho ; Kim, Ji-Sung ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 537~548
DOI : 10.12652/Ksce.2013.33.2.537
In this study, the hydraulic channel routing model was constructed to analysis the effect of flood control with the operation of Chungju Dam for 2006 flood. Study area was divided with up- and downstream of Chungju Dam in the upper Han River of Paldang Dam. The model was calibrated and verified for the flood event of 1995-2008. The effects of flood control of Chungju Dam were compared with the simulation results without the dam, and the rising effects of stage in the main observation stations were analyzed by the variation of released dam discharge. Consequently, the operation of Chungju Dam for 2006 flood was performed properly, but the effects of flood control of Chungju Dam were so focused in downstream of the dam that institutional complement was demanded to reduce the flood damage in the upper region of the dam. The limit of decision rule of downstream stage in the backwater region of dam was analyzed to solve the problem, and the decision rule of downstream stage was proposed to consider the discontinuity between the backwater region of dam and the design flood of upper stream. The proposed rule will be used to design the reduction of flood damage in upper stream of dam and to apply the analysis of region for flood damage.
The Use of Satellite Image for Uncertainty Analysis in Flood Inundation Mapping
Jung, Younghun ; Ryu, Kwanghyun ; Yi, Choongsung ; Lee, Seung Oh ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 549~557
DOI : 10.12652/Ksce.2013.33.2.549
An flood inundation map is able to convey spatial distribution of inundation to a decision maker for flood risk management. A roughness coefficient with unclear values and a discharge obtained from the stage-discharge rating equation are key sources of uncertainty in flood inundation mapping by using a hydraulic model. Also, the uncertainty analysis needs an observation for the flood inundation, and satellite images is useful to obtain spatial distribution of flood. Accordingly, the objective of this study is to quantify uncertainty arising roughness and discharge in flood inundation mapping by using a hydraulic model and a satellite image. To perform this, flood inundations were simulated by HEC-RAS and terrain analysis, and ISODATA (Iterative Self-Organizing Data Analysis) was used to classify waterbody from Landsat 5TM imagery. The classified waterbody was used as an observation to calculate F-statistic (likelihood measure) in GLUE (Generalized Likelihood Uncertainty Estimation). The results from GLUE show that flood inundation areas are 74.59
for lower 5 % uncertainty bound and 151.95
for upper 95% uncertainty bound, respectively. The quantification of uncertainty in flood inundation mapping will play a significant role in realizing the efficient flood risk management.
A Study on Runoff Analysis of Urban Watershed by Hydrologic Infiltration Experiment of Permeable Pavement
Koo, Young Min ; Jo, Jae An ; Kim, Young Do ; Park, Jae Hyeon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 559~571
DOI : 10.12652/Ksce.2013.33.2.559
Recently, due to increase of the impervious layer, the storage of surface layer has been reduced. Otherwise the peak runoff and the total surface runoff have been raised. Because of larger amount of the peak runoff and the rapid time of concentration, the flood damage of the urban watershed was increased. The groundwater level is descended by reducing the amount of rainfall that infiltrated into the soil. Thereby the hydrologic cycle is degenerated by the dry stream. Therefore, in this study, the evaluation and the quantitative analysis of the percolation effect were performed through the infiltration experiment of permeable pavement, which is one of the ways that can reduce the problem of the dry stream. Also the SWMM model is used to analyze the effect of the hydrologic cycle for permeable pavement in Changwon stream and Nam stream watersheds, with the coefficient of permeability from the infiltration experiments.
Comparison of Wave Pressure Acting on the Front Wall According to the Porosity of Caisson Breakwater Having the Cap of Wave Chamber
Oh, Sang-Ho ; Ji, Chang-Hwan ; Oh, Young Min ; Jang, Se-Chul ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 573~584
DOI : 10.12652/Ksce.2013.33.2.573
This study experimentally investigated the change in distribution of wave pressure on the front wall according to the variation of the front wall porosity of the caisson breakwater having the cap of wave chamber. First, the wave pressure for the non-porous caissson corresponding to zero porosity was measured and compared with the pressure formula suggested by Goda(1974). The analysis showed that the measured pressure distribution fairly well agreed with the Goda formula, which confirmed the accurate measurement of wave pressure in the present experiment. In case of the porous caisson, meanwhile, the experiment was performed by varying the front wall porosity as 0.2, 0.25, and 0.3. The wave pressure distribution at the front wall showed little difference according to the porosity for most of the test wave conditions, whereas the pressure slightly increased with the porosity for some test waves whose wave heights and periods were relatively large. However, the difference according to the porsosity was insignificant for the wave force at the front wall.
Experimental Study for the Resonance Effect of the Power Buoy Amplitude
Kweon, Hyuck-Min ; Koh, Hyeok-Jun ; Kim, Jung-Rok ; Choi, Young-Hwan ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 585~594
DOI : 10.12652/Ksce.2013.33.2.585
In this study, laboratory experiments and numerical simulations were conducted to test the performance of resonance power buoy system proposed by Kweon et al.(2010). The system is composed of a linear generator and a mooring buoy. The mover of the linear generator mainly has heave motion driven by vertical oscillation of the buoy. In this system, the velocity discrepancy between the mover and the buoy makes electricity. However, ocean wave energy as a natural resource around Korean peninsula is comparatively small and the driving force for producing electricity is not enough for commercialization. Therefore, it is necessary that the buoy motion be amplified by using resonance characteristics. In order to verify the resonance effects on the test power buoy, the experimental investigations were conducted in the large wave flume (length of 110 m, width of 8 m, maximum depth of 6 m) equipped with regular and random plunger wave generator. The resonance draft of test power buoy is designed for the corresponding period of incident wave, 1.96 sec. Regular wave test results show that the heave response amplitude operator(RAO) by a test buoy has the amplification of 5.66 times higher compared to the wave amplitude at the resonance period. Test results of random waves show that the buoy has the largest spectrum area of 20.73 times higher at the point of not the resonance period but the shorter one of 1.85 sec. Therefore this study suggests the resonance power buoy for wave power generation for commercial application in the case of the coastal and oceanic area with smaller wave energy.
A Study on Analysis of Moored Ship Motion Considering Harbor Resonance
Kwak, Moon Su ; Moon, Yong Ho ; Pyun, Chong Kun ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 595~608
DOI : 10.12652/Ksce.2013.33.2.595
This paper is proposed the computation method of moored ship motion considering harbor resonance, and estimated that the harbor resonance have an effect on moored ship motion. The computation of harbor resonance was used CGWAVE model and the computation of moored sip motion was used the Green function method expressed by three dimensions. This method was verified with the field observation data of moored ship motion, and the application of actual harbor was investigated with wave field data and down time record data in Pohang New Harbor. The resonance periods in Pohang New Harbor that obtained from wave field data were 80, 33, 23, 8 minute, which are the long waves, and 42, 54, 60 second, which are the infra-gravity waves inside harbor slip. The simulated results of harbor resonance were corresponded with the wave field data. This study was investigated on 5,000 ton, 10,000 ton and 30,000 ton ship sized in Pier 8 of Pohang New Harbor that the harbor resonance has effect on moored ship motion from simulated results of ship motion in case of included resonance and excluded resonance. In case of included resonance, the ship motion have increased by 12~400 percent when compared with results of excluded resonance. We could find that the harbor resonance have still more an effect on the surge and heave motions of a large size ship and the roll and yaw motions of a small size ship.
Oxidation of Endocrine Disrupting Chemicals Using Sodium Persulfate
Lim, Chan Soo ; Yun, Yeo Bog ; Kim, Do Gun ; Ko, Seok Oh ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 609~617
DOI : 10.12652/Ksce.2013.33.2.609
The objective of this study was to evaluate the oxidation method to remove endocrine disrupting chemicals in reverse osmosis(RO) retentate for the reuse of wastewater effluent. Oxidation of organic pollutants was induced by the persulfate catalyzed by Fe(II). Affecting factors such as initial pH and ionic strength on the Fe(II) catalyzed persulfate oxidation were evaluated.
-ethynylestradiol (EE2) degradation efficiency decreased as pH and ionic strength increased. However, the efficiency increased as chloride ion concentration increased due to the influence of radical transfer.
Estimation of Shear Wave Velocity of Earth Dam Materials Using Artificial Blasting Vibration Test
Ha, Ik-Soo ; Kim, Nam-Ryong ; Lim, Jeong-Yeul ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 619~629
DOI : 10.12652/Ksce.2013.33.2.619
The objective of this study is to estimate shear wave velocity of earth dam materials using artificially generated vibration from blasting events and to verify its applicability. In this study, the artificial blasting and vibration monitoring were carried out at the site adjacent to Seongdeok dam, which is the first blasting test for an existing dam in Korea. The vibrations were induced by 4 different types of blasting with various depths of blasting boreholes and explosive charge weights. During the tests, the acceleration time histories were recorded at the bedrock adjacent to the explosion and the crest of the dam. From frequency analyses of acceleration histories measured at the crest, the fundamental frequency of the target dam could be evaluated. Numerical analyses varying shear moduli of earth fill zone were carried out using the acceleration histories measured at the bedrock as input ground motions. From the comparison between the fundamental frequencies calculated by numerical analyses and measured records, the shear wave velocities with depth, which are closely related to shear moduli, could be determined. It is found that the effect of different blasting types on shear wave velocity estimation for the target dam materials is negligible and the shear wave velocity can be consistently evaluated. Furthermore, comparing the shear wave velocity with the previous researchers` empirical relationships, the applicability of suggested method is verified. Therefore, in case that the earthquake record is not available, the shear wave velocity of earth dam materials can be reasonably evaluated if blasting vibration test is allowed at the site adjacent to the dam.
Development of Miniature Cone and Characteristics of Cone Tip Resistance in Centrifuge Model Tests
Kim, Jae Hyun ; Kim, Dong Joon ; Kim, Dong Soo ; Choo, Yun Wook ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 631~642
DOI : 10.12652/Ksce.2013.33.2.631
The standard CPT(Cone Penetration Test), which can be easily performed to investigate in-situ soil engineering properties, has been widely used. CPT are also widely being utilized in centrifuge model tests. In this study, a miniature cone with 10mm diameter was developed and its applicability in the centrifuge was evaluated. The developed miniature cone was equipped with a four degree-of-freedom in-flight robot. A series of cone penetration tests was performed under four centrifuge acceleration levels. As results, the cone resistances measured at the same confining stress within shallow penetration depth were affected by the centrifugal accelerations. The critical depth was proportional to the cone diameter and relative density. Cone resistances results below the critical depth and soil parameters obtained from the laboratory tests were compared with those by previously proposed empirical relations.
Evaluation on Stress-Strain-Strength Behavior of the Textile Encased Soils via Triaxial Compression Tests
Yoo, Wan-Kyu ; Kim, Byoung-Il ; Cho, Wanjei ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 643~653
DOI : 10.12652/Ksce.2013.33.2.643
Recently, there are an increasing number of studies on the method of wrapping the outer wall of granular piles with geosynthetic fibers such as geotextile or geogrid that has a certain level of tensile strength as an alternative method for the ground improvement techniques. In this study, triaxial compression tests are performed on the sand and clay specimen encased with various textiles to evaluate the reinforcing effect with regard to the tensile strength of the textile. Furthermore, triaxial compression tests are performed on the clay specimen inserted by sand only and sand encased with geosynthetics to compare behavioral differences between the conventional sand compaction pile and geosynthetic encased sand pile with regard to the replacement ratio,
and the tensile strength of the geosynthetics. Based on the experimental results, the strength enhancement due to the textile is affected by the longitudinal tensile strength rather than the transverse one of the applied textile. The effect of the confinement by the textile encasement results in the large increase of the cohesions. The overall behaviors, such as shear strength, pore pressure parameter at failure and stress ratio, of the geosynthetic encased sand pile is quite different from those of the conventional sand compaction pile.
A Study on the Rock Mass Classifications and Reinforcement in Unconsolidated Sedimentary Rock Tunnel
Kim, Nakryoong ; Jeong, Sangseom ; Ko, Junyoung ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 655~666
DOI : 10.12652/Ksce.2013.33.2.655
A number of highway projects are in progress in Korea to accommodate increasing transportation demands. As the highway route becomes more complex, some projects include tunneling through unconsolidated sedimentary rock. Since an unconsolidated sedimentary rock mainly consists of rock and ground mass, the behavior and characteristics in unconsolidated sedimentary rock tunnel are quite different from typical rock tunnel. However, construction case histories and rock classifications method on unconsolidated sedimentary rock tunnel had not been developed or studied domestically. Consequently the case studies and rock classification system for unconsolidated sedimentary rock are required to better understand its behavior for tunneling. In this study, rock mass classification method is proposed to identify unconsolidated sedimentary rock based on point load and slake durability tests. Based on this, the proposed method of unconsolidated sedimentary rock can be applied well through comparisons with the results of convergence measurement.
A Mode Choice Model with Market Segmentation of Beneficiary Group of New Transit Facility
Kim, Duck Nyung ; Choi, A Reum ; Hwang, Jae-Min ; Kim, Dong-Kyu ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 667~677
DOI : 10.12652/Ksce.2013.33.2.667
The introduction of a new transit facility affects mode share of travel alternatives. The multinomial logit model, which has been the most commonly used for estimating mode share, has difficulty in reflecting heterogeneity of travelers` choices, and it has a limitation on grasping their characteristics of mode choice. The limitation may lead to over- or under-estimation of the new transit facility and bring about significant social costs. This paper aims to find a methodology to overcome the problem of preference homogeneity. It also applies market segmentation structure of separating the whole population into direct and indirect beneficiary to consider their preference heterogeneity. A mode choice model is estimated on data from Jeju Province and statistically tested. The results show that mode transfer rate of direct beneficiaries that inhabit in downtown areas increases as the new transit facility provides more advanced services with higher costs. The results and the model suggested in this study can contribute to improving the accuracy of demand forecasting of new transit facilities by reflecting heterogeneity of mode-transfer patterns.
An Analysis of Decision Making Process in Voluntary Reducing Private Car Use
Lee, Backjin ; Kim, Joon-Ki ; Yi, Choonyong ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 679~689
DOI : 10.12652/Ksce.2013.33.2.679
To relieve Green-house Gas Emission is the key issue in urban area. Urban transport policies have focused on the reduction of private car use. The most common of these is Travel Demand Management(e.g., congestion charge, environmental tax, etc.) that forces individuals to reduce their private car use. An alternative way is Mobility Management(MM) that induces individuals to voluntarily change their car use through communications. MM is founded on social psychology theory and focuses on individuals` decision making processes to change their perception and attitude on private car use. Although some researchers have reported the relevance of MM approach, still few researches have explicitly studied on individuals` decision making processes. Therefore, the aims of the paper are to analyze the decision making process of individuals and to provide the basis of introducing MM approach in Korea. Structural equation model(SEM) is applied for the analysis of individuals` decision making process. A empirical study shows that psychological factors such as perception/attitude on global environment or individual norms impact significantly to reduce private car use and accordingly the relevance of introducing MM approach instead of imposing regulations or expanding transport facilities.
The Outlier-Filtering Algorithm for National Highway Continuous Traffic Counts Data
Shin, Jae Myong ; Lee, Sang Hyup ; Kim, Hyun Suk ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 691~702
DOI : 10.12652/Ksce.2013.33.2.691
In this study the quantitative outlier-filtering algorithm has been developed using the smoothing method based on the day-of-the-week traffic volume variation pattern and then, in order to test the effectiveness of the algorithm, it has been used to identify outliers from the traffic volume data collected at 14 continuous traffic counts sites on the national highways in the year 2010. The test results are satisfactory since the filtering rate is 98.2% for normal days and the mis-filtering rate is 8.0% for abnormal days. Therefore, the algorithm will be able to be used for roughly-but-quickly filtering outliers from the collected traffic volume data.
A Study on the Sensibility Evaluation for the Human-centered Design of Rope Platform Screen Door(RPSD)
Jung, Byung Doo ; Kim, Hyun ; Shin, Kangwon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 703~709
DOI : 10.12652/Ksce.2013.33.2.703
Recently, the study on the commercialization technology of Rope Platform Screen Door (RPSD) is on the process. The study is specifically on RPSD, which the rope screen ascends to allow passage with securing safety of passenger and the condition of aboveground station. For this human-centered design of RPSD, it is important to present system technology. However, it is also necessary to scientifically measure and research the emotions, senses or minds of users in the future. Therefore, this study analyzed the human factors to be considered with designing the system on RPSD, which is installed in Nokdong Station on Gwangju Subway as a trial. Moreover, the emotional evaluation was done by analyzing the factors as how they are effected in general; it processed by checking whether it is safe, height of rope is stable, it has openness (pressure) or strong by examining the moments that a set of ropes blocks rail from platform, and when train is arrived.
Drivers` Understanding of Traffic Pavement Markings
Shin, Kangwon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 711~718
DOI : 10.12652/Ksce.2013.33.2.711
Traffic pavement markings are one of primary transportation facilities that provide drivers with various road information directly. Thus, a clear understanding of traffic pavement markings is utmost important to improve traffic safety as well as to establish a proper traffic culture. However, no past studies examined drivers` understanding of traffic pavement markings in Korea. Hence, this study investigated drivers` understanding of traffic pavement markings through an elaborated administrated survey, and analyzed the relationship between various drivers` characteristics and understanding regarding pavement marking via cross-classification table and logistic model. The analysis results show that drivers have limited understanding regarding the purpose of the markings. Specifically, the average understanding of pavement markings is 57.41%: the lowest understanding is 25.88% for yield pavement marking, and the highest understanding is 91.18% for advanced pedestrian crosswalk pavement marking. This study also revealed that the understanding of some pavement markings are somewhat influenced by user group such as drivers with suspended or revoked driver licenses, but the overall understanding of pavement markings are not significantly affected by drivers` characteristics such as gender and driving experiences at
Activity-based Approaches for Travel Demand Modeling: Reviews on Developments and Implementations
Lim, Kwang-Kyun ; Kim, Sigon ; Chung, SungBong ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 719~727
DOI : 10.12652/Ksce.2013.33.2.719
Four-step travel-demand modeling based on a trip-level has been widely used over many decades. However, there has been a wide variance between forecasted- and real-travel demands, which leads less reliable on the model implications. A primary reason is that person`s real travel behavior is not properly captured throughout the model developments. An activity-based modeling (ABM) approach was proposed and developed toward increasing the accuracy and reality of person`s travel behavior in the U.S. since 1990`, and stands as a good alternative to replace the existing trip-based approach. The paper contributes to the understanding of how the ABM approaches are dissimilar to the trip-based modeling approach in terms of estimation units, estimation process, their pros and cons and etc. We examined three activity-based travel demand model systems (DaySim, CT-Ramp, and CEMDAP) that are most commonly applied by many MPOs (Metropolitan Planning Organization). We found that the ABM approach can effectively explain multi-dimensional travel decision-makings and be expected to increase the predictive accuracy. Overall, the ABM approach can be a good substitute for the existing travel-demand methods having unreliable forecasts.
Development of Environmental Load Calculation Method for Airport Concrete Pavement Design
Park, Joo-Young ; Hong, Dong-Seong ; Kim, Yeon-Tae ; Jeong, Jin-Hoon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 729~737
DOI : 10.12652/Ksce.2013.33.2.729
The environmental load of concrete pavement can be categorized by temperature and moisture loads, which mean temperature distribution, and drying shrinkage and creep in the concrete slab. In this study, a method calculating the environmental load essential to mechanistic design of airport concrete pavement was developed. First, target area and design slab thickness were determined. And, the concrete temperature distribution with slab depth was predicted by a pavement temperature prediction program to calculate equivalent linear temperature difference. The concrete drying shrinkage was predicted by improving an existing model to calculate differential shrinkage equivalent linear temperature difference considering regional relative humidity. In addition, the stress relaxation was considered in the drying shrinkage. Eventually, the equivalent linear temperature difference due to temperature and the differential shrinkage equivalent linear temperature difference due to moisture were combined into the total equivalent linear temperature difference as terminal environmental load. The environmental load of eight civilian and two military airports which represent domestic regional weather conditions were calculated and compared by the method developed in this study to show its application.
Computational Fluid Dynamic(CFD) Analysis-based Feasibility Study on Wind Power Generation due to Traveling Vehicles on Highway
Jeon, Je Yeon ; Han, Kwan Mun ; Song, Jong Sub ; Park, Seunghee ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 739~748
DOI : 10.12652/Ksce.2013.33.2.739
In this study, analytical works for the induced winds due to traveling vehicles on highway have been conducted by Computation Fluid Dynamics (CFD). The traveling condition was considered in two cases: (a) single direction and (b) bi-direction. The analysis was focused on the effects of the induced winds on the upper part of a median strip while the aerodynamic characteristics of the vehicles were directly analyzed in the previous studies. From the analysis results, it has been found that the maximum magnitude of the induced winds was 2.2 m/s when the vehicles travel with the speed of 50 km/h. Additionally, 4.0 m/s and 5.3 m/s were obtained with the speed of 90 km/h and 120 km/h, respectively. Especially, the induced winds was generated about 84% of the vehicle speed at 1.0 m above from the median strip when the vehicles travel with the speed of 120 km/h. The induced winds was maintained during the very short period while the traveling. conclusively, it is noted that the wind power generation can be possible by using the small-sized wind power generators installed on median strips throughout the analytical results in this study.
Effect of ERP Implementation for Public Owner - Based on Case Study
Kim, Hyoun Young ; Park, Hee-Sung ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 749~755
DOI : 10.12652/Ksce.2013.33.2.749
The public corporations have already implemented ERP to improve productivity, quality, and cost saving. This paper presents the result of business process improvement based on implementation of ERP. Therefore, this paper performed case study of K corporation. Survey was conducted to define the degree of improvement and evaluation method was presented using AHP. The weights for each business area is assigned based on AHP. Then ERP is evaluated in efficiency, work transparency, information sharability, and easy of use. It is meaningful achievement considering its short term implementation. The human resource management shows a relatively larger improvement than other management processes. However, information sharability shows relatively low improvement than others. This quantified result of user-oriented subjective evaluation on ERP implementation will contribute to evaluate the impact of ERP for owner organizations.
Classification of Factors for Intangible Asset Valuation of Construction Engineering Consulting Firm
Phi, Seung Woo ; Hur, Young Ran ; Seo, Jong Won ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 757~769
DOI : 10.12652/Ksce.2013.33.2.757
Intangible assets for construction engineering consulting firms are very important for their valuation, because engineering consulting is typical knowledge-based business which creates value based on technical expertise and human resources. This paper presents the intangible asset classification model based on the concept of value creation in construction engineering consulting firm and proposes intangible asset valuation methodology using System Dynamics and survey data. Utilization of the valuation methodology presented in this paper would increase the public awareness of intangible assets in construction engineering consulting firm and, thus, contribute to the growth of the engineering consulting industry by realistic and accurate valuation of intangible assets.
Orders Status Analysis on the Successful Bidder Decision Method of Turnkey Alternative Tendering Construction
Park, Hong-Tae ; Lee, Yang-Kyu ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 771~780
DOI : 10.12652/Ksce.2013.33.2.771
Inspection system which was performed in the past selected the final winning bidder by separating Pre-Qualification, the basic design evaluation and price evaluation. However, turnkey and alternative bidding construction has selected way to determine the successful bidder as the best design and the most low cost method, comprehensive evaluation method (bid price adjustment, design score adjustments, weights standard), the best design and the fixed amount method from january 1, 2010 to the present. Due to these institutional problems, orders institutions were often a way to determine the successful bidder to apply differently for identical or similar construction. Therefore this study winning bidder selection criteria through analysis of construction the number and construction order performance, order performance by work division and institutional orders, the weights bidder order performance and orders status of turnkey alternative tendering construction to civil part performed in domestic.
Development of the Approximate Cost Estimating Model Using Statistical Inference for PSC Box Girder Bridge Constructed by the Incremental Launching Method
Kim, Sang-Bum ; Cho, Ji-Hoon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 781~790
DOI : 10.12652/Ksce.2013.33.2.781
This research focuses on development of the conceptual cost estimation models for I.L.M box girder bridge. The current conceptual cost estimation for public construction projects is dependent on governmental average unit price references which has been regarded as inaccurate and unreliable by many experts. Therefore, there have been strong demands for developing a better way of conceptual cost estimating methods. This research has proposed three different conceptual cost estimating method for a P.S.C. girder bridge built with the I.L.M method. Model (I) attempts to seek the proper breakdown of standard works that are accountable for more than 95 percentage in total cost and calculates the amount of standard work`s materials from the standard section and volume of I.L.M box girder bridge. Model (II) utilizes a correlation analysis (coefficient over 0.6 or more) between breakdown of standard works and input data that would be considered available information in preliminary design phase. Model(III) obtains conceptual estimating through multiple-regression analysis between the breakdown of standard works and all of input data related to them. In order to validate the clustering of coverage in the preliminary design phase, the variation of I.L.M cost coverage from multiple-regression analysis[model(III)] has been investigated which result in between -3.76% and 11.79%, comparing with AACE(Association for the Advancement of Cost Engineering) which informs its variation between -5% and +15% in the design phase. The model proposed from this research are envisioned to be improved to a great distinct if reliable cost date for P.S.C. girder bridges can be continually collected with reasonable accuracies.
Development of the Approximate Cost Estimating Model for PSC Box Girder Bridge based on the Breakdown of Standard Work
Kim, Sang-Bum ; Cho, Ji-Hoon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 791~800
DOI : 10.12652/Ksce.2013.33.2.791
Needs for developing a better way of cost estimating process for public construction projects have been widely recognized. Those needs are mainly from the early phases of the project through the construction life cycle due to the its importance to the control process. In contrast to the traditional estimating method based on unit-price references, this research utilized this following process. The first step is analyzing the real cost data from actual cost activities (2000~2010) about the statement of P.S.C(Prestressed Concrete) Box Girder Bridge. The collected data was broken into four categories based on technical construction methods such as I.L.M(Incremental Launching Method), M.S.S(Movable Scaffolding System), F.S.M(Full Staging Method), and F.C.M(Free Cantilever Method). The second, actual design documents including the actual cost estimating documents, drawings and specifications were carefully reviewed to cluster the cost itemized statement from four categories. It was also attempted to seek the proper breakdown of standard works that are responsible for more than 95 percentage in each categories in terms of its cost. The third, this research comes up the index for standard unit materials and unit price of standard work and develops the approximate estimating model applying for the specification(length and breadth of bridges) per square area that the user takes as well as suggests the practical application plan within the original time alloted.
Reframing Sustainability in Consideration of Climate Change and Natural Hazards: Focusing on the U.S. Natural Hazards Mitigation Trend and Case Analysis
Kwon, Tae Jung ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 801~810
DOI : 10.12652/Ksce.2013.33.2.801
The main purpose of this study is to reframe sustainability or sustainable development concept in the field of planning in consideration of climate change and natural hazards. The new concept is expected to provide a theoretical foundation for upcoming hazard mitigation measures addressing climate change. The first and main argument of the new concept is that environmental protection should be inclusive enough to address urban (or community) security from current natural hazards. The second is that the balance between structural and nonstructural mitigation measures is critical to cope more effectively with extreme natural hazards in the era of climate change and also with conflicts driven by three goals of sustainability--environmental protection, economic development, and social justice. The following studies, based on this new concept of sustainablity, are expected (1) to address new participation methods for the conflict resolution, (2) to explore detailed and substantive planning strategies and creative technical and institutional solutions for environmental protection, natural hazard mitigation, and conflict resolution. Two of APFM(the Associated Programme on Flood Management)`s three natural hazard risk criteria, Exposure and Vulnerability, may guide the exploration.
An Analysis on the Determinants of Mountainous and Coastal Area`s Housing Value Caused by the Characteristics of the Natural Environment
Choi, Yeol ; Kim, Hyeong Jun ; Kim, Su Jin ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 811~819
DOI : 10.12652/Ksce.2013.33.2.811
This study aims to analyze determinants of mountainous and coastal area`s housing value caused by the characteristics of the natural environment. As the current issue of housing value is throwing the spotlight on the climate change recently, environmental features are significantly important than before. There were a lot of studies on the influence of environmental characteristics to the housing price but these studies were mostly dealing with the housing price in especially apartments nearby Han-river in Seoul, South Korea. To have differences with existing studies, environmental characteristics estimating housing value are classified as 8 elements including the view, the wind speed, and the humidity. The result of this study is in following; there were few significant environmental variables in mountainous housing value growth model. This means people living in mountainous area recognize on environmental factors more such as housing or complex characteristics. People living in coastal area are much more sensitive environment variables in their residence value than mountainous area. Especially, the view for the ocean is the most important variable in housing value, and wind speed is second positively significant. Humidity and safety of disaster are negatively significant variables.
The Fatigue Life Evaluation of Aged Continuous Welded Rail on the Urban Railway
Kong, Sun-Young ; Sung, Deok-Yong ; Park, Yong-Gul ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 2, 2013, Pages 821~831
DOI : 10.12652/Ksce.2013.33.2.821
As a result of recent research, it is reported that the periodic replacements criterion of rails is able to extend as grinding rail surface and using the continuous welded rail (CWR). In this study, we carried out fatigue tests on existing laid rails. Based on the test results, an S-N curve expressing the remaining life of laid rails at a fracture probability of 50% was obtained using weighted probit analysis suitable for small-sample fatigue data sets. As rails used for testing had different histories in terms of accumulated tonnage, the test data were corrected to average out the accumulated tonnage. We estimated the remaining service lives for laid rails on the urban railway using equations developed in the past to estimate rail base bending stress and that surface irregularities into consideration. Therefore, estimating the remaining service life of laid rails showed that the rail replacement period could be extended over 200 MGT, although it is necessary to remove longitudinal rail surface irregularities at welds by grinding. Also, the fatigue test results under fatigue limit, Haibach`s rule appling half slope of S-N curve under the fatigue limit was considered more reasonable than modified Miner`s rule for estimating rail fatigue life.