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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 35, Issue 6 - Dec 2015
Volume 35, Issue 5 - Oct 2015
Volume 35, Issue 4 - Aug 2015
Volume 35, Issue 3 - Jun 2015
Volume 35, Issue 2 - Apr 2015
Volume 35, Issue 1 - Feb 2015
Selecting the target year
Structural Damping Ratio of Steel Plate Concrete(SC) Shear Wall at the Low Stress Level Identified by Vibration Test
Cho, Sung Gook ; So, Gihwan ; Kim, Doo Kie ; Han, Sang Mook ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 255~264
DOI : 10.12652/Ksce.2015.35.2.0255
Steel plate concrete (SC) structure has been developed as a new structural type. Rational damping value shall be determined for the seismic design of SC structure. This study evaluated damping ratio of SC structure through experiments. For the study, a SC shear wall specimen was constructed and dynamically tested on the shaking table. Acceleration time history responses measured from testing were converted to the transfer functions and analyzed by using experimental modal analysis technique. The structural damping ratio of the specimen was identified as 4% to critical. Considering the shaking table test was performed at the excitation level corresponding to the low stress level of the specimen, 4% could be suggested as a structural damping for design of SC structure for operating basis earthquake.
Evaluation of Local Damage of SC Wall using Local Collision Simulation
Woo, Dong In ; Chung, Chul Hun ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 265~274
DOI : 10.12652/Ksce.2015.35.2.0265
The structural safety of nuclear power plant against impact from aircraft crash has been performed so far in two viewpoints such as local behavior and global behavior, and the local behavior has been evaluated using local damage evaluation formulas suggested based on the results of experimental data of RC (Reinforcement Concrete) wall. However, few data have been collected from recent research to evaluate the local behavior and damage of SC (Steel plate reinforced Concrete) wall, which is recently applied to the newly designed nuclear power plant. In this study, local damages of SC wall and RC wall against an idealized aircraft engine projectile impact are evaluated through FE simulation analyses with various wall thicknesses and steel ratio. Through analysis of local collision simulation results of SC and RC wall, the penetration depth of SC wall and RC wall are compared.
Fatigue Evaluation of Precast Concrete Deck Connection using Ultra-High Performance, Fiber Reinforced Concrete
Lee, Jun-Ki ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 275~285
DOI : 10.12652/Ksce.2015.35.2.0275
This experimental study presents the fatigue evaluation of a precast deck connected using Ultra-High Performance, Fiber Reinforced Concrete (UHPFRC). Four types of two identical large-scale specimens were fabricated with simplified splice rebar details which had a short splice length of ten times rebar diameter. The flexural behavior of each type of specimens until failure was investigated and fatigue behavior of the same type of specimens was then evaluated using two-million cyclic loading. In the flexural tests, tensile rebars exhibited the deformation exceeding yielding strain but failure mode related to the splice details was not observed in spite of such a short splice length. In the fatigue tests, damage was not appreciably accumulated by the cyclic loading except initial flexural cracks and the stress variations in tensile rebars was less than the allowable stress range. These experimental results demonstrate that all types of specimens exhibited acceptable fatigue performance and indicate that enhanced mechanical properties of ultra-high performance material permits to use a simplified splice details along with short joint width.
Evaluation of Ductility in Reinforced Concrete Members Using Material Models in Eurocode2
Choi, Seung Won ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 287~297
DOI : 10.12652/Ksce.2015.35.2.0287
In concrete structural design provisons, there is a minimum allowable strain of steel to ensure a ductility of RC members and a c/d is limited for the same purpose in EC2. In general, a ductility capacity of RC members is evaluated by a displacement ductility which is a ratio of ultimate displacement to yield displacement, and it is necessary to calculate accurately a yield displacement and an ultimate displacement to evaluate a displacement ductility. But a displacement in members is affected by various member characteristics, so it is hard to calculate a displacement exactly. In this study, a displacement ductility is calculated by calculating a yield displacement and an ultimate displacement through a moment-curvature relationship. The main variables examined are concrete strength, yield strength, steel ratio, spacing of confinement, axial force ratio and concrete ultimate strain. As results, as a concrete strength is increased, a ductility displacement is increased. But as yield strength, steel ratio, spacing of confinement and axial force ratio are increased, a displacement ductility is decreased. And a displacement ductility is necessary to calculate a response modification factor (R) of columns for seismic design, so it is appeared that it is important to calculate a displacement ductility more accurately.
An Experimental Study on Size-effect for Characteristic of Flexural Strength of Pavement Concrete
Lee, Hyeongi ; Oh, Hongseob ; Sim, Jongsung ; Sim, Jaewon ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 299~306
DOI : 10.12652/Ksce.2015.35.2.0299
The quality for the domestic pavement is evaluated based on flexural strength at the age of 28 days in accordance with KS regulation. Most specimens of the flexural tensile strength used currently are relatively large ones with a dimension of
. Accordingly, it is difficult to treat the specimens, and the utilization of a curing tank is low. In this paper, the study tried to resolve the problem by specimen size specified in the code. For this purpose, a flexural strength test was conducted according to the log scale within the specimen size specified by the KS. And, based on the results of this experiment, a comparative analysis was conducted using the prediction formula of Size Effect Law (SEL) proposed by Bazant to examine the correlation between specimen sizes, so as to use the result as basic data for the reduction of the specimen size in the quality evaluation of concrete pavement.
A Study on Prediction of Inundation Area considering Road Network in Urban Area
Son, Ah Long ; Kim, Byunghyun ; Han, Kun Yeon ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 307~318
DOI : 10.12652/Ksce.2015.35.2.0307
In this study, the efficiency of two-dimensional inundation analysis using road network was demonstrated in order to reduce the simulation time of numerical model in urban area. For this objective, three simulation conditions were set up: Case 1 considered only inundation within road zone, while Case 2 and 3 considered inundation within road and building zone together. Accordingly, Case 1 used grids generated based on road network, while Case 2 and 3 used uniform and non-uniform grids for whole study area, respectively. Three simulation conditions were applied to Samsung drainage where flood damage occurred due to storm event on Sep. 21, 2010. The efficiency of suggested method in this study was verified by comparison the accuracy and simulation time of Case 1 and those of Case 2 and 3. The results presented that the simulation time was fast in the order of Case 1, 2 and 3, and the fit of inundation area between each case was more than 85% within road zone. Additionally, inundation area of building zone estimated from inundation rating index gave a similar agreement under each case. As a result, it is helpful for study on real-time inundation forecast warning to use a proposed method based on road network and inundation rating index for building zone.
A Study on Quality Control Method for Minutely Rainfall Data
Kim, Min-Seok ; Moon, Young-Il ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 319~326
DOI : 10.12652/Ksce.2015.35.2.0319
Rainfall data is necessary component for water resources design and flood warning system. Most analysis are used long-term hourly data of surface synoptic stations from the Meteorological Administration, Ministry of land, Infrastructure and Transport and others. However, It will be used minutely data of more high density automatic weather stations than surface synoptic stations expecting to increase the frequency of heavy precipitation. But minutely data has a problem about quality of rainfall data by auto observation. This study analyzed about quality control method using automatic weather station's minutely rainfall data of meteorological administration. It was performed assessment of the quality control that was classified quality control of miss Data, outlier data and rainfall interpolation. This method will be utilized when hydrological analysis uses minute rainfall data.
Development of Multisite Spatio-Temporal Downscaling Model for Rainfall Using GCM Multi Model Ensemble
Kim, Tae-Jeong ; Kim, Ki-Young ; Kwon, Hyun-Han ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 327~340
DOI : 10.12652/Ksce.2015.35.2.0327
General Circulation Models (GCMs) are the basic tool used for modelling climate. However, the spatio-temporal discrepancy between GCM and observed value, therefore, the models deliver output that are generally required calibration for applied studies. Which is generally done by Multi-Model Ensemble (MME) approach. Stochastic downscaling methods have been used extensively to generate long-term weather sequences from finite observed records. A primary objective of this study is to develop a forecasting scheme which is able to make use of a MME of different GCMs. This study employed a Nonstationary Hidden Markov Chain Model (NHMM) as a main tool for downscaling seasonal ensemble forecasts over 3 month period, providing daily forecasts. Our results showed that the proposed downscaling scheme can provide the skillful forecasts as inputs for hydrologic modeling, which in turn may improve water resources management. An application to the Nakdong watershed in South Korea illustrates how the proposed approach can lead to potentially reliable information for water resources management.
Spatial Analysis of Flood Inundation for Ensuring Stream Space
Choi, Cheonkyu ; Kim, Joohun ; Kim, Kyuho ; Kim, Gilho ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 341~351
DOI : 10.12652/Ksce.2015.35.2.0341
This study is to select the areas to ensure stream space or to implement flood defence measures according to flood frequencies by classifying the stream segment using river bed slope in Mangyeong river. The analysis result for each stream segment showed that the variation of flood inundation area was small in upper stream catchment. But in the lower stream area, the inundation area became larger greatly according to the increase of flood return period. This study classified the catchment of each steam segment as the region of ensuring stream space (ESS), below 10% residential area ratio, and the region of reinforcing flood defence (RFD), over 10% residential area ratio. The analysis results showed that the lower stream area included more RFD regions than upper stream area, and the upper stream area included more ESS regions than lower stream area. In future study, the regions stream spaces can be ensured will be analyzed considering the past stream morphology and the positions of wetlands.
Effects of Environmental Infrastructure Regeneration in Urban Region - A Case Study of M Apartment Complex in Daejeon
Park, Kiyong ; Choi, Changkyoo ; Shin, Jongseok ; Park, Heekyeng ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 353~359
DOI : 10.12652/Ksce.2015.35.2.0353
This study introduces a resource recycling system in urban apartment complex using four different technologies. The four technologies, called 4G, include a production technology for reclaimed water (Green water), a biogas production technology from organic waste (Green biogas), a reuse technology of rainwater (Green rainwater), and urban agropark (Green pyramid). Green water is the technology for producing the reclaimed water from wastewater, rainwater and underground water, and the average concentrations of BOD, SS, T-N and coliform of reclaimed water were 7.8mg/L, ND (not detected), 4.9mg/L and ND, respectively. Green biogas is the technology for producing biogas and effluent after treating organic wastes (e.g. food waste and night soil) discharged from households, and the average production rates of hydrogen and methane were
, respectively. Green pyramid, agricultural farm operated by biogas and reclaimed water, provides a healthy and recreational space for residents, and plant growth rates using treated water and reclaimed water showed height of 1.32cm and weight of 112.8g. Therefore, 4G technologies can improve the recycling rate and treatment efficiencies of waste and wastewater in an apartment complex.
Evaluation of Heat Exchange Efficiency and Applicability for Parallel U-type Cast-in-place Energy Pile
Park, Sangwoo ; Kim, Byeongyeon ; Sung, Chihun ; Choi, Hangseok ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 361~375
DOI : 10.12652/Ksce.2015.35.2.0361
An energy pile is one of the novel ground heat exchangers (GHEX's) that is a economical alternative to the conventional closed-loop vertical GHEX. The combined system of both a structural foundation and a GHEX contains a heat exchange pipe inside the pile foundation and allows a working fluid circulating through the pipe, inducing heat exchange with the ground formation. In this paper, a group of energy piles equipped with parallel U-type (5, 8 and 10 pairs) heat exchange pipes was constructed in a test-bed by fabricating in large-diameter cast-in-place concrete piles. In addition, a closed-loop vertical GHEX with 30m depth was constructed nearby to conduct in-situ thermal response tests (TRTs) and to compare with the thermal performance of the cast-in-place energy piles. A series of thermal performance tests was carried out with application of an artificial cooling and heating load to evaluate the heat exchange rate of energy piles. The applicability of cast-in-place energy piles was evaluated by comparing the relative heat exchange efficiency and heat exchange rate with preceding studies. Finally, it is concluded that the cast-in-place energy piles constructed in the test-bed demonstrate effective and stable thermal performance compared with the other types of GHEX.
Optimization for Configuration and Material Cost of Helical Pile Using Harmony Search Algorithm
Na, Kyunguk ; Lee, Dongseop ; Lee, Hyungi ; Choi, Hangseok ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 377~386
DOI : 10.12652/Ksce.2015.35.2.0377
The helical pile is a manufactured steel pile consisting of one or more helix-shaped bearing plates affixed to a central shaft. This pile is installed by rotating the shaft into the ground to support structural loads. Advantages of the helical pile are no need for boring or grout process, and ability to install a pile foundation with relatively light devices. In this study, an optimized design method for helical piles is proposed to minimize the material cost with consideration of the load bearing capacity obtained by the cylindrical shear method. The harmony search meta-heuristic algorithm was adopted for optimization process. The optimized design was verified by comparing with the 2009 International building code. It is noted that the optimization for the configuration of helical piles along with material cost proves to be an out-performed tool in designing helical pile foundation with economic feasibility.
Evaluation of Reducing Cross Section of the Partial Drainage Shield Tunnel Segment using the Model Experiments
Ma, Sang Joon ; Lee, Young Sub ; Kim, Dong Min ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 387~396
DOI : 10.12652/Ksce.2015.35.2.0387
The existing shield tunnel has constructed in the concept of non-drainage uniformly, but the leak has become a problem in the construction and management. The Shield tunnel design allowed for the water and earth pressure bring about the increasing segment thickness and the construction costs. In order to improve these problems, the study of the partial drainage shield tunnel is in progress. In this study, th model experiment was performed to confirm the possibility of the partial drainage shield tunnel. And the water and earth pressure was measured in drainage and undrained condition. Based on the results of model experiments, the effect of water pressure reduction was confirmed by reviewed the structure stability of the real design case.
Development of Safety Performance Function Based on Expressway Alignment Homogeneous Section
Seo, Im-Ki ; Kang, Dong-Yoon ; Park, Je-Jin ; Park, Shin Hyoung ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 397~405
DOI : 10.12652/Ksce.2015.35.2.0397
In the past, expressways focused on mobility. However, the paradigm of expressways fuction today has been changed from fast expressways to safe expressways as people's quality of living and consciousness level heightened. In 2012, 3,550 traffic accidents occurred on expressways and 371 people died. The fatality rate of traffic accidents on expressways is almost twice that on general national roads. This study developed accident forecast models (safety performance functions) based on the number of traffic accidents and traffic volumes on six major lines on expressways. It is difficult to forecast safety performance functions for each expressway line because the lines and the scales of expressways are different from each other; therefore, integrated safety performance functions of six lines were determined first, and the coefficients, which can correct the traffic accidents on each line, were calculated. It is believed that this study will contribute in the safer management of expressways by being used as basic information in the establishment of traffic safety strategies for each expressway line in prevention of traffic accidents. Moreover, more studies would be required in the future, which would suggest reliable accident forecasts by calculating correction coefficients by line through integrated models by groups dependent on the characteristics of each line.
Implementation and Analysis of Railway Design Model using ei-Rail with Joong-Ang and Seo-Hae Lines
Shin, Youngho ; Kim, Jeong Hyun ; Oh, Jitaek ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 407~415
DOI : 10.12652/Ksce.2015.35.2.0407
The railway route and alignment planning have been executed with a limited number of alternatives based on the site pre-survey and the topographic map. This study developed an intelligent railway alignment planning program (ei-Rail) which can derive all the considerable design alternatives and provide the data for the alternative evaluation such as constructions cost, operation cost, and etc. According to the comparisons with prevailing planned railway projects, the time and cost for planning can be reduced as well as the construction costs. This program may contribute to the development of railway industry by reducing the time and cost for planning as well as the total project cost.
The Safety Evaluation of Expressway Geometries by Cross-sectional Analysis Techniques
Seo, Im-Ki ; Choi, Jong-Tae ; Park, Je-Jin ; Park, Shin-Hyoung ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 417~426
DOI : 10.12652/Ksce.2015.35.2.0417
The representative design elements of the road geometric structure are longitudinal slope, horizontal curve radius, super elevation, and transition curve. According to the function of a road, the design standards of these elements is applied by diverse combinations of them. This study divided expressway into homogeneous segments based on longitudinal slope and horizontal curve radius. And then, data required for analysis were matched to each segment, and the safety performance function was built by using the established data. crash modification factors which can explain traffic accident exposure rate were calculated. When the threshold value of horizontal curve radius R=1,000 m was set to 1.0, the crash modification factors at R=300 m was calculated as 1.33, which means that the accident exposure rate is increased by 33%. When the threshold value of the longitudinal slope 0% was set to 1.0, the crash modification factors demonstrated that the accident exposure rate decreases on the upward slope and the accident exposure rate increases on the downward slope. The results of this study can be used as basic information in the design of expressway geometries during the improvement or the construction of expressways.
Analysis on Pedestrian Behavior Focused on Waiting Time and Trial Frequency for Crossing in the Unsignalized Intersection
Jang, Tae Youn ; Oh, Do-Hyoung ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 427~436
DOI : 10.12652/Ksce.2015.35.2.0427
This study analyzes the factors effecting on pedestrian crossing behavior in the unsignalized intersection. Pedestrian crossing behavior is the results of mental stress defined as a combination of environment perception, avoiding accidents, halting collision, and instant crossing decision. It is necessary to make walkable intersection in cities through relieving this stress influenced by personality, traffic condition, and roadway environment. The purpose of study is empirically to examine the crossing behavior such as crossing satisfaction, crossing trial frequency and waiting time based on various factors effecting on crossing intersection by video and questionnaire survey. The
-test is applied to analyze the characteristics of crossing trial frequency according to each factor. Also, the hazard rate model is established to find the factors effecting on waiting time for crossing. Finally, the direct and indirect effects on the pedestrian crossing satisfaction are presented as the results of LISREL.
Analysis of User Satisfaction by Types of Subway Platforms and Transit Stations
Kim, Hwang Bae ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 437~445
DOI : 10.12652/Ksce.2015.35.2.0437
The layout of facilities, in relation to information and navigational displays, has great influence on subway satisfaction, and tend to vary depending on the types of subway platform and transit station. However, until now, few studies have covered such aspects as of yet. Starting from this viewpoint, the purpose of this study was to use an IPA analysis technique to analyze that satisfaction on the importance of facilities to aid in accessibility, such as elevators and escalators, transit amenities and information and navigational displays depending on the types of platform and transit station. To do so, we've classified 15 metropolitan stations according to types of platform and transit station and analyzed differences in user importance and satisfaction as well as improvements for platforms and transit stations of similar type. By the analysis results of this study, we've concluded that the proper selection and positioning of elevator and escalator facilities and information and navigational displays was important when designing the subway station according to platform type (separate platform) and or according to the transit station type (cross, L, T types) where pedestrian flow heavily intersected. We considered that such analysis results would be helpful in the design of new stations and the enhancement of existing stations pursuant to a new direction that minimizes user inconvenience, and that improvement items should be developed first according to the platform and transit station types, which would be helpful in enhancing the efficiency of the subway improvement cost.
A Study on Development and Application of Evaluation Index for Rail Station Area Development Site Using AHP
Shim, Sangwoo ; Lee, Kyujin ; Choi, Keechoo ; Jeon, Seongmin ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 447~453
DOI : 10.12652/Ksce.2015.35.2.0447
This study proposed evaluation indices and weights for objectively evaluating the validity of rail station area development site. In this study, evaluation indices were selected by quantification, application of a new rail station, sustainability of data collection, correlation of indices and expert decision-making. As a result, 8 indices such as railway and subway demand, the ratio of land price etc. were selected and these indices could be classified into demand, feasibility and regionality. AHP (Analytic Hierarchy Process) result showed that the weights of demand (0.486) and feasibility (0.369) were more important than that of regionality (0.145). The application result on 75 existing railway stations showed that an important consideration of railway station area development site was a rail and subway demand on Seoul metropolitan area and was a feasibility on local area. Therefore, the selection of a rail station area development site may be determined based on demand and feasibility. In addition, these results are expected to be utilized as basic data for making decisions on the rail station area development at an initial stage.
Accessibility Measure of Cultural Facilities Using Urban Network Analysis
Park, Tae-Sun ; Lee, Mee-Young ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 455~464
DOI : 10.12652/Ksce.2015.35.2.0455
Investments into existing cultural facilities are determined based on administrative district-based indices like population and area. Such macro judgment indices, however, fail to consider accessibility of cultural facilities from neighboring administrative districts and thus create problems including wasted budgets and duplicated investments. More recently, the government has made it a goal to increase the level of citizen awareness of these facilities, but achieving this requires the integration of neighboring administrative districts such that characteristics including transportation network and buildings are reflected in a comprehensive manner. This research therefore looks into Urban Network Analysis (UNA) as a means to investigate accessibility of cultural facilities. Use of UNA will make it possible to analyze the transportation network as well as building distribution, explained by building density, settled population, and other important building factors, in tandem, leading to the concentration of cultural facilities and the surrounding economic district being more properly reflected, and thus allowing for greater explanatory power in determining the level of accessibility. To test this, four target research districts were chosen from within the Gyeonggi Province and analyzed in terms of the accessibility of their everyday cultural facilities. Of the four districts of Gunpo, Anyang, Uiwang, and Gwacheon, accessibility of the first two districts, was found to be high, while accessibility was found to be relatively low for the latter two districts. This finding indicates that cultural facilities investments should be concentrated in the districts of Gunpo and Anyang.
A Study on Curing Level Prediction Model for Varying Chemical Composition of Epoxy Asphalt Mixture
Jo, Shin Haeng ; Kim, Nakseok ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 465~470
DOI : 10.12652/Ksce.2015.35.2.0465
The curing of epoxy asphalt mixture depends on the chemical reaction of epoxy resin and the curing agent. The curing level of epoxy asphalt mixture needs to be predicted in order to decide traffic opening time and to establish further construction plans. In this study, chemical analysis of the prediction model was executed to expand the applicability of the previous prediction model. Consequently, the curing level prediction model of epoxy asphalt concrete mixture was proposed using the concentration ratio and the acid value ratio. According to the results of outdoor curing experiments, the final prediction model showed that the correlation coefficient is greater than 0.971. Precise prediction results of different composition epoxy asphalt were obtained by reflecting the chemical composition ratios in the curing level prediction model.
Performance Prediction Model for Public-Private Partnership Projects Considering Stakeholders' Profitability
Yeo, Dong Hoon ; Yu, Giwon ; Lee, Kang-Wook ; Han, Seung-Heon ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 471~480
DOI : 10.12652/Ksce.2015.35.2.0471
The market of public-private partnership (PPP) projects has reduced from 9.4 trillion won in 2007 to 4.5 trillion won in 2012. However, the need of PPP projects is brought up by a massive down scale of government financial business. Previous studies regarding PPP projects mostly evaluate profitability from the financial perspective or analyze risk factors as a whole. Although PPP projects generally have complex structure involving diverse stakeholders, such as contractor, financial investor, and special purpose company (SPC) operators, existing studies have rarely considered the different viewpoints of PPP project stakeholders. Therefore, purpose of this study is to develop a structural equation model (SEM) considering the diverse stakeholders of PPP projects. To this end, the authors first reviewed the organizational structure of PPP projects. Next, the identification of the factors affecting project profitability are done via comprehensive literature reviews. After that, we conducted in-depth interviews and questionnaire surveys to reflect stakeholders' perspectives (contractors, financial investors, and SPC operators). As a result, a SEM model is developed to analyze direct and indirect effect on the PPP project performances. Finally, using the analysis results, relevant implications and directions for improvements are discussed. The prediction of the business performance of contractor, financial investor, and SPC operator is expect to be possible through the model developed and supports the strategy deduction that is appropriate for the participants.
A Study on Control of Sealing Robot for Cracks of Concrete Surface
Cho, Cheol-Joo ; Lim, Kye-Young ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 481~491
DOI : 10.12652/Ksce.2015.35.2.0481
Since the crack in the surface of the concrete acts as the main reason influencing the life span of the structure, regular inspections and maintenance are required. The sealing required for maintenance of the concrete surface is a method of repairing the crack in the surface in the beginning, and is effective in preventing additional cracks and expansion that occurs with time. However, sealing on large sized structures such as tall buildings or bottom parts of bridges are difficult to ensure safety of the workers due to inadequate working environments. Due to this reason, the importance of the need for sealing automation for the maintenance of large sized concrete structures is emerging. This study proposes two control methods to apply robot systems to the sealing of cracks on the bottom parts of concrete bridges. First is the method of automatically tracking the trajectory of cracks. The robot gets the trajectory of the cracks using video information obtained from cameras. Comparing the previous several points and new point, the next point can be estimated. Thus, the trajectory of the crack can be tracked automatically. The other method is sealing by maintaining steady force to the contacting surface. The concrete surface exposed to an external environment for a long time gets an irregular roughness. If robots are able to carry out sealing while maintaining a steady contact force on these rough surfaces, complete equal sealing can be maintained. In order to maintain this equal force, a force control method using impedance is proposed. This paper introduces two developed control methods to apply to sealing robots, and conducts a Lab Test and Field Test after applying to a robot. Based on the test results, opinions on the possibilities of field application of the robot applied with the control methods are presented.
Application of Construction Equipment Fleet Management System through the Case Study of Air and Vessel Traffic Control Technology
Park, Ji Soo ; Seo, Jong Won ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 493~500
DOI : 10.12652/Ksce.2015.35.2.0493
The importance of the air and vessel traffic control center is increasing rapidly after the recent accident of 'Sewol ferry'. Aviation, marine, and the logistics sectors are already using monitoring and control technology widely. However, the monitoring and control system for complex and dangerous construction sites operation has yet to be employed. A monitoring/control system is required for effective communication between the control center and the construction equipment fleet at a construction site, and also the exact role that notifies accurate process and identification of hazards on construction sites as needed. Therefore, this paper presents the study about communication between the construction equipment fleet and the control center through the comparison of air traffic, marine, and logistics control systems for the development of construction equipment fleet management system.
An Approach for Solid Modeling and Equipment Fleet Management Towards Low-Carbon Earthwork
Kim, Sung-Keun ; Kim, Gyu-Yeon ; Park, Ju-Hyun ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 501~514
DOI : 10.12652/Ksce.2015.35.2.0501
Earthwork is a basic operation for all forms of civil works and affects construction time, cost and productivity. It is a mechanized operation that needs various construction equipment as a group and uses a lot of fuel for construction equipment. But, the problem is that earthwork operation is usually performed by equipment operator's heuristic and intuition, which can cause low productivity, high fuel consumption, and high carbon dioxide emission. As one of solutions for this problem, the fleet management system for construction equipment is suggested for effective earthwork planning, optimal equipment allocation, efficient machine operation, fast information exchange, and so forth. The purpose of this research is to suggest core methods for developing the equipment fleet management system. The methods include 3D solid parametric model generation, soil distribution using Cctree data structure, equipment fleet construction and equipment fleet operation. A simulation test is performed to verify the effectiveness of the equipment fleet management system in terms of equipment operating ratio, fuel usage, and
Assessing Distribution of Degree of Saturation for Track Transition Zone Using Soil Water Characteristic Curve
Choi, Chanyong ; Lee, Jungmin ; Kwon, Hyeok Min ; Oh, Jeongho ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 515~524
DOI : 10.12652/Ksce.2015.35.2.0515
The number of occurrence of differential settlement and track irregularity at track transition zone recently comes to increase, which leads to frequent maintenance activities that have an impact on train operation. Such track transition zone damages are attributed to the change of mechanical properties of fill materials due to environmental factors such as rainfall and freeze, and thaw. Consequently, this study attempts to establish the soil water characteristic curve (SWCC) of fill materials, and conduct seepage analysis to assess the distribution of degree of saturation (DOS) for track transition zone in case of rainfall. The SWCC of fill materials was successfully obtained using filter paper test method. The results of seepage analysis revealed that rainfall intensity, the slope of backfill, backfill condition (fill or cut), and SWCC are significantly influential in controlling the distribution of DOS.
3D Indoor Modeling Based on Terrestrial Laser Scanning
Hong, Seung Hwan ; Cho, Hyoung Sig ; Kim, Nam Hoon ; Sohn, Hong Gyoo ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 2, 2015, Pages 525~531
DOI : 10.12652/Ksce.2015.35.2.0525
According to the increasing demand for 3D indoor spatial information, the utilization of a terrestrial laser scanner comes to the fore. However, the research for the comparison between a terrestrial laser scanning method and a traditional surveying method is insufficient. The paper evaluated the time-efficiency and the locational accuracy of an AMCW type and a direct TOF type of terrestrial laser scanning methods in comparison with the observation using a total station. As a result, an AMCW type showed higher time-efficiency than a direct TOF type and the RMSE between the two types of data was
. Moreover, the terrestrial laser scanning method showed twice higher time-efficiency than the observation using a total station and the RMSE between the two data was
. The results indicate that the terrestrial laser scanning method has better profitability and performance for 3D indoor modeling than the traditional survey using a total station. In the future, a terrestrial laser scanner can be efficiently utilized in the construction of 3D indoor spatial information.