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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 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
Selecting the target year
An Investigation on the Nonlinear Shear Behavior of FRP Composites Considering Temperature Variation and Fabricating Parameters
Jung, Woo-Young ; Hwang, Jin-Seop ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 833~841
DOI : 10.12652/Ksce.2013.33.3.833
In the case of composite material, a variety of characteristics were expressed depending on the materials that were composed of. In this study, the materials showing non-linear shear behavior were investigated among FRP composite. Each specimen was designed and analyzed according to ASTM D4255 method: regulations on the 2-rail. The dependent variables included in this experiment were a variety of fiber, fiber volume ratio, fiber array direction, temperature, material homogeneity. For determination of characteristics based on the fiber array, fiber array direction of 0, 30, 45, and 60 degrees were selected for test specimen. Temperature of 25, 40, 60, and
were considered for investigation of FRP materials`shear behavior based on the external temperature. Nonlinear shear behavior was observed throughout the FRP composite material in this study. Also, using vinyl ester resins, high fiber volume ratio, and fiber array direction of 45 degree appeared to show the most prominent nonlinear shear behavior. As for the findings related to the temperature change, non-linear behavior was decreased as the external temperature increased. For factory manufactured product, non-linear behavior was relatively at parity in comparison to the behavior found in the hand lay-up FRP composite specimen.
Experimental Evaluation for Ultimate Flexural Behaviors of PSC beams with A Corroded Tendon
Youn, Seok-Goo ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 843~854
DOI : 10.12652/Ksce.2013.33.3.843
This paper presents experimental research work for the evaluation of ultimate flexural behaviors of prestressed concrete beams with a corroded tendon. In order to evaluate the effects of loss of prestress or loss of tendon area on the ultimate flexural strength of prestressed concrete beams, static load tests are conducted using five prestressed concrete beams. After exposing prestressing tendons in two test beams using 25mm drill bit, the exposed tendons were corroded using an accelerating corrosion equipment to simulate loss of tendon area. During the tests, steel strains, concrete strains and displacements at the center of test beams were measured, and acoustic emission measurements were conducted to detect wire fractures. Based on the test results, evaluation method for predicting flexural strength of prestressed concrete beams with corroded tendons is investigated. In addition, evaluation methods for predicting the existence of corroded tendons in post-tensioned prestressed concrete beams at service loads are discussed.
Effects of Thermal Aging of Natural Rubber Bearing on Seismic Performance of Bridges
Oh, Ju ; Jung, Hie-Young ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 855~864
DOI : 10.12652/Ksce.2013.33.3.855
The dynamic characteristics of natural rubber bearings, which are used as isolator, are dependent on the main rubber`s dynamic behaviors and nonlinear properties. Rubber materials tend to undergo an aging process under the influence of mechanical or environmental factors, so they inevitably end up facing damage. A main cause of aging like this is known to be oxidization, which occurs through the heat of reaction at high temperatures. Accordingly, in this study an accelerated thermal aging test was carried out in order to compare the characteristic values of the bearings before and after thermal aging occurs. As a result of this experiment, it was found that a thermal aging phenomenon could have some effects on shear stiffness, energy absorption, and equivalent damping coefficients of the bearings. Furthermore, a deterioration in the dynamic properties of the natural rubber bearings caused by the thermal aging was applied to an actual bridge and then the effects of such thermal aging on the seismic performance of the bridge were also compared and analyzed based on numerical analysis. As a result of this analysis, it was found that the changes in the basic properties of the natural rubber bearings caused by the thermal aging bring only a minor effect on the seismic performance of bridges.
Buckling Analysis of Pipelines with Reduced Cross Section
Choi, Dong-Ho ; Ko, Young-Chan ; Gwon, Sun-Gil ; Lee, Joung-Sun ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 865~873
DOI : 10.12652/Ksce.2013.33.3.865
This paper proposes a theoretical solution of elastic critical buckling load of infinitely long pipelines with non-uniform thickness under external pressure. The non-uniform cross section of pipelines can be considered as corroded or stiffened pipelines so that this paper can be a fundamental research of pipelines that are essential technology for offshore industries. The theoretical solution of pipelines with non-uniform thickness is derived with an assumption that a cylindrical shell under external pressure can be considered as a simple ring. The eigenfunctions are derived to obtain the critical buckling load. The reduced thickness and the reduced range are considered as variables in parametric analysis. The finite element analysis is performed to verify the theoretical solutions and the results of the analytic method and the finite element method are in good agreement.
Seismic Behavior and Performance Evaluation of Uckling-restrained Braced Frames (BRBFs) using Superelastic Shape Memory Alloy (SMA) Bracing Systems
Hu, Jong Wan ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 875~888
DOI : 10.12652/Ksce.2013.33.3.875
The researches have recently progressed toward the use of the superelastic shape memory alloys (SMAs) to develop new smart control systems that reduce permanent deformation occurring due to severe earthquake events and that automatically recover original configuration. The superelastic SMA materials are unique metallic alloys that can return to undeformed shape without additional heat treatments only after the removal of applied loads. Once the superelastic SMA materials are thus installed at the place where large deformations are likely to intensively occur, the structural system can make the best use of recentering capabilities. Therefore, this study is intended to propose new buckling-restrained braced frames (BRBFs) with superelastic SMA bracing systems. In order to verify the performance of such bracing systems, 6-story braced frame buildings were designed in accordance with the current design specifications and then nonlinear dynamic analyses were performed at 2D frame model by using seismic hazard ground motions. Based on the analysis results, BRBFs with innovative SMA bracing systems are compared to those with conventional steel bracing systems in terms of peak and residual inter-story drifts. Finally, the analysis results show that new SMA bracing systems are very effective to reduce the residual inter-story drifts.
An Experimental Study on Compressive Loading Capacity of Precast Concrete Truss System
Han, Man-Yop ; Jeon, Se-Jin ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 889~900
DOI : 10.12652/Ksce.2013.33.3.889
In a large scale of excavation for the foundation of large-sized structures and underground structures, a considerable amount of earth pressure can occur. Steel beams that have been used to form a temporary structure to support earth pressure may be less economical and less efficient in resisting the high earth pressure. To cope with this problem, PCT(Precast Concrete Truss) system has been devised and investigated both experimentally and analytically. A proper connection method between the concrete truss members was proposed to accommodate fast assembly and disassembly. Full-scale test of PCT system was performed to verify the load-carrying capacity of the PCT system including the connections. The test results were compared with those of structural analysis. The test specimen which corresponds to PCT strut attained the ultimate load without buckling, but the detail of connector members needs to be improved. It is expected that precast concrete truss members can be efficiently incorporated into a temporary structure for deep and large excavation by replacing conventional steel beams.
An Experimental Study on Strength Properties, Size Effect, and Fatigue Behaviour of Concrete under Biaxial Flexural Stress State
Zi, Goangseup ; Kim, Jihwan ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 901~907
DOI : 10.12652/Ksce.2013.33.3.901
In this study, flexural strength properties of concrete under biaxial stress state were experimentally investigated. Tests for size effect and fatigue behaviour of concrete under biaxial stress were carried out by the ASTM C 1550 and the biaxial flexure test(BFT). The results given by the biaxial tests were compared to those by the third-point bending test. Test results showed that biaxial flexural strengths obtained from the ASTM C 1550 and the biaxial flexure test are greater than the strength by the third-point bending test. As the size increases, the uniaxial and biaxial flexural strength decreases. However, the slope of the size effect of the biaxial strength was greater than that of the uniaxial strength. Finally, the fatigue response of concrete under the biaxial stress state was similar with that for uniaxial stress state.
Long-term Durability Characteristics of Fly ash Concrete Containing Lightly Burnt MgO Powder
Jang, Bong-Seok ; Choi, Seul-Woo ; Lee, Kwang-Myong ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 909~916
DOI : 10.12652/Ksce.2013.33.3.909
Concrete containing lightly burnt MgO has long term expansibility. It also could compensate for the thermal shrinkage of mass concrete, because the hydration of MgO proceeds at a slow pace to long-term age. Thus, lightly burnt MgO has been applied to the construction of mass concrete such as dams. Recently, the expansion characteristics of MgO concrete with fly ash that could be applied to mass concrete for the reduction of hydration heat have been studied and however, limited studies on its durability. This study investigates the long-term durability characteristics of fly ash concrete with lightly burnt MgO. The durability tests on carbonation, freezing-thawing, diffusion of chloride, and resistance to sulfate attack were carried out for MgO concrete with curing for 360 days in submerged condition with different temperature of 20 and
. The results reveal that MgO concrete shows a greater resistance of carbonation, diffusion of chloride, and resistance to sulfate attack. On the other hand the resistance of freezing-thawing was little influenced by MgO powder.
Application of Fuzzy Multi-criteria Decision Making Techniques for Robust Prioritization
Han, Bong Gu ; Chung, Eun Sung ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 917~926
DOI : 10.12652/Ksce.2013.33.3.917
This study presents the feasibility of fuzzy multi-criteria decision making (MCDM) techniques for the robust prioritization of projects. It is applied to water resources planning problem. Results from weighted sum method (WSM), analytic hierarchy process (AHP), revised analytic hierarchy process (R-AHP), and TOPSIS are compared with those from Fuzzy WSM, Fuzzy, AHP, Fuzzy R-AHP, and Fuzzy TOPSIS. For the calculation, all weights on criteria and the normalized data were obtained from the same investigation. As a result, the rankings from four MCDM techniques are slightly different while those from fuzzy MCDM show the comparatively consistent ranking. Therefore, it is desirable to use fuzzy MCDM technique when MCDM is used for the prioritization problem, since fuzzy MCDM can include the uncertain variability of input data and weighting values on criteria.
Reduction of Rainfall Runoff by Constructing Underground Storage Tank
Song, Chang Geun ; Seo, Il Won ; Jung, Young Jai ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 927~935
DOI : 10.12652/Ksce.2013.33.3.927
In this study, reservoir routings for 1 hour-50 year precipitation frequency were carried out at the Engineering Water Fall and the Amphitheater located at the downstream of Seoul National University Dam. Main analysis was focus on the following matters: (1) storage amount by the tank; (2) reduction of the outflow and the peak water surface elevation; (3) change of phase lag time; and (4) design of new boxes at the inlet and outlet of storage tank. As for the storage tank of
built in the Amphitheater area, the tank induced 49.43 % storage effect, 28 min. phase lag time, and reduced the peak outflow by 49.64 %. In addition, the peak water surface elevation was lowered by 35 cm compared with that of
storage tank. It is concluded that combined management of previous storage facility and new underground storage tank would control the excessive rainfall runoff efficiently.
The Effect of Uncertainty in Roughness and Discharge on Flood Inundation Mapping
Jung, Younghun ; Yeo, Kyu Dong ; Kim, Soo Young ; Lee, Seung Oh ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 937~945
DOI : 10.12652/Ksce.2013.33.3.937
The accuracy of flood inundation maps is determined by the uncertainty propagated from all variables involved in the overall process including input data, model parameters and modeling approaches. This study investigated the uncertainty arising from key variables (flow condition and Manning`s n) among model variables in flood inundation mapping for the Missouri River near Boonville, Missouri, USA. Methodology of this study involves the generalized likelihood uncertainty estimation (GLUE) to quantify the uncertainty bounds of flood inundation area. Uncertainty bounds in the GLUE procedure are evaluated by selecting two likelihood functions, which is two statistic (inverse of sum of squared error (1/SAE) and inverse of sum of absolute error (1/SSE)) based on an observed water surface elevation and simulated water surface elevations. The results from GLUE show that likelihood measure based on 1/SSE is more sensitive on observation than likelihood measure based on 1/SAE, and that the uncertainty propagated from two variables produces an uncertainty bound of about 2% in the inundation area compared to observed inundation. Based on the results obtained form this study, it is expected that this study will be useful to identify the characteristic of flood.
Determination of Ecological Flow at the Confluence of Nakdong River and Gumho River Using River2D
Seo, Il Won ; Park, Inhwan ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 947~956
DOI : 10.12652/Ksce.2013.33.3.947
In this study, WUA (Weighted Usable Area) was calculated to determine ecological flow at the confluence of Nakdong River and Gumho River by using River2D. To calibrate River2D, simulation results of River2D were compared with calibrated HEC-RAS simulation results and the optimum parameters were determined. After parameter calibration, WUA of Zacco platypus and Zacco temmincki which are dominant species in Nakdong River was calculated with changing upstream flowrate. From the result, WUA is changed according to flowrate and growth stage. In the flowrate-WUA/A graph, ecological flow can be determined as
in Nakdong River and
in Gumho River. After dredging for Four major rivers restoration project, WUA of Zacco platypus and Zacco temmincki were calculated by using the ecological flow. The results show that WUA after dredging are decreased when compared with undredged condition. WUA of Common carp is 2~3 times bigger than WUA of Zacco platypus and Zacco temmincki at the dredged condition in Nakdong River.
Flooding Risk Assessment Using Flooding Characteristic Values
Ahn, Jeonghwan ; Kim, Kunwoo ; Cho, Woncheol ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 957~964
DOI : 10.12652/Ksce.2013.33.3.957
This research is on the methodology of flood risk assessment using flooding characteristic values. Necessity of design magnitude for flood control considering floods was judged by plotting peak flow with respect to frequency and duration, and flooding magnitude was defined with 6 flooding characteristic values which were proposed to be significant factors when assessing flooding magnitude. Precipitation data used in the assessment modeling were applied by combining all the possible precipitation events. After overlapping the simulated results with precipitation matrix by flooding characteristic values, contour map was drawn, and Flooding characteristic contour graph for possible rainfall events were suggested in respect of all possible precipitation. Flooding characteristic contour graph for possible rainfall events was confirmed that reducing of damage magnitude of each flood characteristic value was figured out easily. The flood risk assessment methods suggested in this study would be a good reference for urban drainage system design, which only focuses on pipe conduit.
Run-out Modeling of Debris Flows in Mt. Umyeon using FLO-2D
Kim, Seungeun ; Paik, Joongcheol ; Kim, Kyung Suk ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 965~974
DOI : 10.12652/Ksce.2013.33.3.965
Multiple debris flows occurred on July 27, 2012 in Mt. Umyeon, which resulted in 16 casualties and severe property demage. Accurate reproducing of the propagation and deposition of debris flow is essential for mitigating these disasters. Through applying FLO-2D model to these debris flows and comparing the results with field observations, we seek to evaluate the performance of the model and to analyse the rheological model parameters. Representative yield stress and dynamic viscosity back-calculated for the debris flows in the northern side of Mt. Umyeon are 1022 Pa and 652
, respectively. Numerical results obtained using these parameters reveal that deposition areas of debris flows in Raemian and Shindong-A regions are well reproduced in 63-85% agreement with the field observations. However, the propagation velocities of the flows are significantly underestimated, which is attributable to the inherent limitations of the model that can`t take the entrainment of bed material and surface water into account. The debris flow deposition computed in Hyeongchon region where the entrainment is not significant appears to be in very good agreement with the field observation. The sensitivity study of the numerical results on model parameters shows that both sediment volume concentration and roughness coefficient significantly affect the flow thickness and velocity, which underscores the importance of careful selection of these model parameters in FLO-2D modeling.
Prediction of Water Quality Effect of Watershed Runoff Change in Doam Reservoir
Noh, Hee Jin ; Kim, Jung Min ; Kim, Young Do ; Kang, Boo Sik ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 975~985
DOI : 10.12652/Ksce.2013.33.3.975
In this research, the integrated modeling system by coupling of a watershed model, a reservoir model, and a river model has been constructed in Doam reservoir watershed. Because of domestic climate characteristics, it is inevitable to construct the dam for control of flood, water use, and power production due to the heavy rain in the summer. Especially, when the dam is constructed on the stream for these kinds of purpose, it is necessary to consider this region as one watershed and also to make the integrated system for simulation and management. In this study, SWAT model was constructed for watershed modeling and EFDC-WASP model was constructed for simulating the hydrodynamic and water quality of the reservoir and the downstream in Doam dam watershed. Also, the water quality improvement equipment for demonstration was applied in the upstream part of Doam reservoir, which shows the applicability of the developed integrated modeling system.
An Experimental Study on Hydraulic Stability of Non-toxic Revetment Block
Kim, Sang Woo ; Koo, Young Min ; Kim, Young Do ; Park, Jae Hyeon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 987~995
DOI : 10.12652/Ksce.2013.33.3.987
The purpose of this study is to examine the hydraulic stability of non-toxic revetment technique for eco-friendly design of the domestic river restoration. Recently, instead of the flood control function-oriented river management policy for the engineering efficiency, the improvement of the environmental performance for the ecological river restoration project is implemented. However, the inappropriate hydraulic design criteria of the new revetment technique happen to the economic losses at flood season frequently. The hydraulic stability of the riprap and the block include the banks of rivers, riverbed protection, scour protection and so on. In this study, the high speed experimental channel was developed, which has the maximum velocity of 3.5 m/s, to perform the hydraulic experiments of the block method with non-toxic glue with various conditions to find the critical velocity of the revetment block for the hydraulic stability.
Analysis of Hydraulic Characteristics of Flood Plain Using Two-Dimensional Unsteady Model
Ku, Young Hun ; Song, Chang Geun ; Kim, Young Do ; Seo, Il Wo ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 997~1005
DOI : 10.12652/Ksce.2013.33.3.997
Since the cross-sectional shape of the Nakdong river is compound type, the water stage rises up to the top of the flood plane, as the flow discharge increases during the extreme rain storm in summer. The recent increase of rainfall intensity and flood frequency results in the immersions of parks and hydrophilic facilities located in the flood plain. Therefore it is necessary to analyze the hydraulic characteristics evolved by the extreme rain storm in the flood plain. The study reach ranging from the Gangjeong Goryeong Weir and the Dalseong Weir, where several hydraulic facilities are located along the channel, was selected and numerical simulations were conducted for 42 hours including the peak flood of the typhoon Sanba. The 2-D transient model, FaSTMECH was employed and the accuracy of the model was assessed by comparing the water level between the simulation results and the measured ones at a gauging station. It showed a high correlation with
of 0.990, AME of 0.195, and RMSE of 0.252. In addition, the inundation time, the inundation depth, the inundation velocity, and the shear stress variation in the flood plain facilities were analyzed.
Stochastic Probability Model for Preventive Management of Armor Units of Rubble-Mound Breakwaters
Lee, Cheol-Eung ; Kim, Sang Ug ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1007~1015
DOI : 10.12652/Ksce.2013.33.3.1007
A stochastic probability model based on the non-homogeneous Poisson process is represented that can correctly analyze the time-dependent linear and nonlinear behaviors of total damage over the occurrence process of loads. Introducing several types of damage intensity functions, the probability of failure and the total damage with respect to mean time to failure has been investigated in detail. Taking particularly the limit state to be the random variables followed with a distribution function, the uncertainty of that would be taken into consideration in this paper. In addition, the stochastic probability model has been straightforwardly applied to the rubble-mound breakwaters with the definition of damage level about the erosion of armor units. The probability of failure and the nonlinear total damage with respect to mean time to failure has been analyzed with the damage intensity functions for armor units estimated by fitting the expected total damage to the experimental datum. Based on the present results from the stochastic probability model, the preventive management for the armor units of the rubble-mound breakwaters would be suggested to make a decision on the repairing time and the minimum amounts repaired quantitatively.
Influence of Soil Characteristic and Rainfall Intensity on Matric Suction of Unsaturated Weathered Soil Slope
Kim, Yong Min ; Lee, Kwang Woo ; Kim, Jung Hwan ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1017~1025
DOI : 10.12652/Ksce.2013.33.3.1017
The monolithically coupled finite element analysis for a deformable unsaturated soil slope is performed to investigate matric suction distribution on a soil slope subjected to rainfall infiltration, which can consider the hydraulic-mechanical characteristics for the analysis. The soil-water characteristic curves (SWCC) are experimentally determined to estimate three types of hydraulic properties of domestic areas. Based on the physical properties, the distribution of matric suction is investigated by considering the major factors, such as soil conditions, rainfall intensities, and slope angles. It is found from the results of this study that the matric suction rapidly decreases with an increase in rainfall intensity, regardless a slope angle. The slope surface is more easily saturated when its saturated hydraulic conductivity is smaller than rainfall intensity, and for the case of multi-layered soil slope, hydraulic characteristics of slope surface has a significant influence on matric suction distribution.
Effect of Rainfall-Patterns on Slope Stability in Unsaturated Weathered Soils
Kim, Byeong-Su ; Park, Seong-Wann ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1027~1035
DOI : 10.12652/Ksce.2013.33.3.1027
In this study, two rainfall patterns are utilized for practical consideration of rainfall phenomena in unsaturated soil slope design. One is the I.D.F (Intensity-Duration-Frequency) method which is an existing design rainfall method and ignores the effect of the variation of the rainfall according to the time. The other is the Huff method which considers this effect oppositely. First, the safety of factor of the slope according to the variation of an initial suction which means the precedent rainfall effect was examined by means of the application of the I.D.F method. Through the application of two rainfall patterns, it was discussed how the rainfall pattern affects the factor of safety of the slope. As a result, it is found that the Huff method is more practical on the evaluation of the slope stability than the I.D.F method.
An Experimental Investigation of the Variations of the Elastic Wave Velocities with Compaction Energy for Railway Roadbed Materials
Kim, Hak-Sung ; Jung, Young-Hoon ; Mok, Young-Jin ; Lee, Jin-Wook ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1037~1047
DOI : 10.12652/Ksce.2013.33.3.1037
A systematic laboratory compaction testing was performed with the laboratory seismic measurements of the compacted specimens sampled from various compaction fills and was supplemented with in-situ seismic testing to investigate the effects of compaction energy on the elastic wave velocities of the railway roadbed materials. The both variances of the compressive and shear wave velocities with moisture content curve (
-w curves) are similar to the general trend of the density-moisture content curve(
-w curve). At the wet side of optimal moisture content (OMC), either
does not significantly increase, which is well reflecting the no gaining in density with the increasing compaction energy exceeding modified-D compaction effort.
increases linearly with
at the dry side of OMC, while it does exponentially at the wet side. The in-situ wave velocities were found to be influenced by the level of confinement and
was more sensitive to compaction energy than
Design Method for Cast-in-place Energy Pile Considering Equivalent Heat Exchange Rate
Min, Sunhong ; Park, Sangwoo ; Jung, Kyoungsik ; Choi, Hangseok ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1049~1061
DOI : 10.12652/Ksce.2013.33.3.1049
In this paper, a relative heat exchange rate is numerically compared for cast-in-place concrete energy piles with different heat exchange pipe configurations, and a new design method for energy piles is proposed. An equivalent heat exchange rate was estimated for the W-type (one series loop), multiple U-type (four parallel loops), and coil-type heat exchanger installed in the same large-diameter drilled shaft. In order to simulate a cooling operation in summer by a CFD analysis, the LWT (leaving water temperature) into a energy pile was fixed at
and then the EWT (entering water temperature) into a heat pump was monitored. In case of continuously applying the artificial maximum cooling load for 100 hours, all of the three types of heat exchangers show the marginally similar heat exchange rate. However, in case of intermittently applying the cooling load with a cycle of 8 hours operation-16 hours off for 7 consecutive days, the coil type heat exchanger exhibits a heat exchange rate only 86 % of the multiple U-type due to measurable thermal interference between pipe loops in the energy pile. On the other hand, the W-type possesses the similar heat exchange rate to the multiple U-type. The equivalent heat exchange rates for each configuration of heat exchangers obtained from the CFD analysis were adopted for implementing the commercial design program (PILESIM2). Finally, a design method for cast-in-place concrete energy piles is proposed along with a design chart in consideration of typical design factors.
Variation in Characteristics of Elastic Waves in Frozen Soils According to Degree of Saturation
Park, Jung-Hee ; Kang, Min-Gu ; Lee, Jong-Sub ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1063~1075
DOI : 10.12652/Ksce.2013.33.3.1063
The strength of frozen soils is one of the significant design parameters for the construction in frozen ground. The properties of frozen soils should be investigated to understand the strength of frozen soils. The objective of this study is to figure out the characteristics of elastic waves in frozen soils, which reflect the constituent and physical structure of frozen soils in order to provide fundamental information of those according to the degree of saturation. Freezing cell is manufactured to freeze specimens, which are prepared with the degree of saturation of 10%, 40%, and 100%. Piezo disk elements are used as the compressional wave transducers and Bender elements are used as the shear wave transducers. While the temperature of specimens changes from
, the velocities, resonant frequencies and amplitudes of the compressional and shear waves are investigated based on the elastic wave signatures. Experimental results reveal that the elastic wave velocities increase as the degree of saturation increases. The variation of resonant frequencies coincide with that of elastic wave velocities. A marked discrepancy in amplitudes of compressional and shear waves are observed at the temperature of
. This study renders the basic information of elastic waves in frozen soils according the degree of saturation.
Selecting and Assessing Vulnerable Zones of Snow Damage in Urban Areas - the case of City of Busan
Koo, Yoo Seung ; Lee, Sung Ho ; Jung, Juchul ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1077~1086
DOI : 10.12652/Ksce.2013.33.3.1077
Recent huge losses of both life and property have occurred by unexpected natural disasters. We studied snow damages, an important natural disaster issue because it happens more frequently in recent years. This study tries to select vulnerable areas of snowfall in advance and then establish climate change adaptation policy for minimizing unexpected snowfall damage. Busan, where is our study area, has hilly in downtown areas so that topography characteristics of the roads such as slope, elevation and aspect are vulnerable to snowfall. The sudden snowfall in Busan causes traffic jam and causes some schools in hilly to close some schools. At this moment, the adaptation policy has to be established for infrastructure (such as roads) in advance, because prediction of anomaly climate due to global warming is so difficult beside the damage of natural disaster is huge. Therefore, the purpose of this study is contribute to selecting and assessing vulnerable zones of snow damage focusing topography characteristics of the roads and then evaluating the degree of risk of vulnerable zones.
Social Cost Comparison of Air-Quality based on Various Traffic Assignment Frameworks
Lee, Kyu Jin ; Choi, Keechoo ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1087~1094
DOI : 10.12652/Ksce.2013.33.3.1087
This study aims at enhancing the objective estimation of social cost of air quality due to mobile emission. More specifically, it examines the difference between the daily oriented and hourly oriented estimation results of social air quality cost and draws implications from the comparative analysis. The result indicates that the social cost of air quality differs up to approximately 24 times depending on the analysis time period. Moneywise, the difference between daily and hourly assignments amounts to the average of 653.5 billion won whereas only 1% of error occurred in the estimation result based on peak and nonpeak based hourly assignment. This study reaffirms the need for time-based travel demand management for emission reduction, and confirms the feasibility of emission estimation by travel demand forecasting method over the conventional method employed by the CAPSS.
Suggestion of Improving and Estimating Parking Space Section Considering Proper Position of Car-Stopper
Kwon, Sung-Dae ; Park, Je-Jin ; Lee, Jun-Young ; Ha, Tae-Jun ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1095~1104
DOI : 10.12652/Ksce.2013.33.3.1095
The number of vehicles registered in Korea is rapidly increasing and will reach 18.26 million as of June 2011. The rapid increase of large-size passenger cars and RVs among this number is causing damage to other vehicles when parked in currently installed parking lots, increased civil complaints from the damage, and inconveniences to people trying to pass through parking lots as well. In particular, the car-stoppers indiscriminately installed at the parking lots are also causing accidents and adding to parking problems, causing economic losses. Accordingly, there should be new regulations for the amount of parking space per vehicle and for locations to install the car-stoppers. The research has first reviewed the distribution ratio of vehicle models from home and abroad for the width and length of the vehicles by each model, parking space per vehicle where the car-stoppers are installed and examples of changes in distribution ratio. In addition, the amount of parking space per vehicle was calculated with consideration for various specifications by each car model. As a result, margin width of full sized car is decreased by 18~21mm on the existing width. This is judged decreases accident of parking lot, because length of the front of car is not deviate parking Space Section. In conclusion, presented improvement ideas for parking plans with enhanced convenience and safety from the aspect of the drivers. Parking lot relevant businesses will also be maximized in terms of cost and efficiency when the criteria for the structure of parking lots and their installation is established and the improved parking plan is applied in the future.
Effects of Weather and Traffic Conditions on Truck Accident Severity on Freeways
Choi, Saerona ; Kim, Mijoeng ; Oh, Cheol ; Lee, Keeyong ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1105~1113
DOI : 10.12652/Ksce.2013.33.3.1105
Understanding the characteristics of truck-involved crashes is of keen interest because such crashes are highly associated with greater potential leading to severer injury. The purpose of this study is to identify factors affecting injury severity of truck-involved crashes on freeways. In addition, a binary logistic regression technique is applied to identify causal factors affecting truck crash severity under normal and adverse weather conditions. Major findings from the analyses are discussed with truck operations strategies including speed enforcement, variable speed limit, and truck lane restriction, from the safety enhancement point of view. The results of this study would be useful for developing traffic control and operations strategies to reduce truck-involved crashes and injury severity in practice.
A Study on Estimating Route Travel Time Using Collected Data of Bus Information System
Lee, Young Woo ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1115~1122
DOI : 10.12652/Ksce.2013.33.3.1115
Recently the demands for traffic information tend to increase, and travel time might one of the most important traffic information. To effectively estimate exact travel time, highly reliable traffic data collection is required. BIS(Bus Information System) data would be useful for the estimation of the route travel time because BIS is collecting data for the bus travel time on the main road of the city on real-time basis. Traditionally use of BIS data has been limited to the realm of bus operating but it has not been used for a variety of traffic categories. Therefore, this study estimates a route travel time on road networks in urban areas on the basis of real-time data of BIS and then eventually constructs regression models. These models use an explanatory variable that corresponds to bus travel time excluding service time at the bus stop. The results show that the coefficient of determination for the constructed regression model is more than 0.950. As a result of T-test performance with assistance from collected data and estimated model values, it is likely that the model is statistically significant with a confidence level of 95%. It is generally found that the estimation for the exact travel time on real-time basis is plausible if the BIS data is used.
Capacity of Urban Freeway Work Zones
Lee, Mi Ri ; Kim, Do-Gyeong ; Kim, Hyo-Seung ; Lee, Chungwon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1123~1130
DOI : 10.12652/Ksce.2013.33.3.1123
This paper aims to estimate work zone base capacity by the number of lanes for urban freeway. To do this, data were collected from the field survey and the database system maintained by traffic control center, and analyzed with four different methods such as the average maximum observation flow rate, headway, regression analysis, and parameter inspection. The work zone base capacity for urban freeway is estimated based on the average maximum observation flow rate and headway method, which are more reliable methods compared to others. The average capacity is 1,650pcphpl when the design speed is 80km/h. The capacity of four lanes one-way work zones was about 1,700pcphpl, while one of 2 lanes one-way work zones was about 1,600pcphpl. The capacity reduction rates for each are 0.15 and 0.2, respectively. The smaller the number of lane is, the more base capacity is reduced. For verification of results, we estimate the capacity by simulation analysis using PARAMICS, and compare with analytical results by a statistical method. This research can be used for efficient and systemic management of work zone in the urban freeway.
A Study on Applicability of TRANSIMS to Interrupted Traffic Flow at Road Segments in Urban Area
Jung, Kwnagsu ; Do, Myungsik ; Lee, Jongdal ; Lee, Yongdoo ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1131~1142
DOI : 10.12652/Ksce.2013.33.3.1131
This study aims to verify the applicability of TRANSIMS (TRansportion ANalysis SIMulation System) in interrupted traffic flow through calibration and validation process based on observation data; such as headway, traffic volume, speed, and travel time from Dalguberl Boulevard in Dae-gu metropolitan city. On this study, several micro-simulation parameters are derived from the calibration and validation process through performing a headway comparison and applying an ID back tracking methodology. As a result, it is figured out that actual circumstances of Korean roadway; for example, traffic volume per lane, speed, and travel time, can be applied on the TRANSIMS. Especially, it was possible to find out the influence of cell size parameter to traffic flow characteristic of simulation. However, it is hard to conclude that TRANSIMS is applicable to Korean roadway environment with studying particular target area. Therefore, additional studies; such as more case studies with various types of road, signal, and land use, will be required to localize TRANSIMS to Korea.
A Study on Noise Reduction of Quiet Pavement through the Noise Level Prediction and the Economic Analysis
Jo, Shin Haeng ; Jang, Jung Soon ; Kim, Wan Sang ; Kim, Nakseok ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1143~1151
DOI : 10.12652/Ksce.2013.33.3.1143
Reasonable methods are needed to predict the noise level of new/existing roads and to select means of noise reduction. In this study, the noise reduction effects of both soundproof walls and quiet pavements were predicted. The noise reduction effects of quiet pavements were predicted by measurement data obtained using the CPX method in test pavements. The noise reduction effect was predicted by KHTN program when applied to soundproof walls and quiet pavement. As a result, the predicted noise level was similar to the measured one. The design method was suggested by an economic analysis using noise benefit of predicted noise reduction. The research suggests that the optimum alternative has to be determined using noise prediction method and life-cycle cost analysis.
Comparative Study on the Bond Strength between Direct Tensile Test and Indirect Tensile Test for Bonded Concrete Overlay
Kim, Young Kyu ; Lee, Seung Woo ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1153~1163
DOI : 10.12652/Ksce.2013.33.3.1153
Bonded concrete overlay is a favorable maintenance method since the material properties are similar to existing concrete pavements. In addition, bonded concrete overlay has advantage of structural performance based on being bonded together, both for the overlay layer and the existing pavement which perform as one monolithic layer. Therefore, it is important to have a suitable bond strength criteria for long term performance of bonded concrete overlay. This study aimed to investigate the affecting of bond strength on various bond characteristics, and to compare the bond strength between direct tensile test and indirect tensile test due to various conditions such as overlay materials, compressive and flexure strength of existing pavement, and deterioration status of existing pavement. As a result of this study, bond strength occurred by both of direct and indirect tensile test due to monotonic load is highly correlated such as coefficient of determination of 0.75 and P-value of 0.002. However, bond strength by indirect tensile test was relatively higher than bond strength by direct tensile test. It was known that correlation between direct and indirect tensile test was possible to use the characteristics analysis of bond fatigue behavior based on bond strength due to cyclic load which can simulate real field behavior of bonded concrete overlay.
Development of Construction Benchmarking for Oversea Industrial Projects
Park, Hee-Sung ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1165~1171
DOI : 10.12652/Ksce.2013.33.3.1165
The oversea construction contract amount has sharply increased since 2003. The contractor`s capability for EPC and project management is a key factor for a successful industrial construction project. Construction performance measurement and evaluation is needed to improve contractor`s project management capability. Therefore, this paper proposes the construction performance benchmarking program for oversea industrial projects. Performance metrics consists of project cost, schedule, quality, and safety. Data from 10 oversea industrial projects were collected and analyzed. Also, this paper describes the process for development of the benchmarking program and lessons learned from industry are summarized. Finally, this paper recommends how sustainable benchmarking program should be established and implemented.
A Benchmarking Study on Green Roads Certification Policies using Case Studies
Kim, Sang-Bum ; Kwak, Hyun-Jun ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1173~1180
DOI : 10.12652/Ksce.2013.33.3.1173
The construction industry has been a major player in Korean economy growth and it has been accountable for more than 15% of GDP during the last decade. However, fast-growing construction industry has also produced some unpleasant side-effects. Environmental problems are identified one of the main issues in the Korean construction industry and they are closely related to minimizing the carbon emission and delivering environmental-friendly green products. The movement of green construction, now, is considered the next driving force for the industry which has significant impacts on the future. This research investigates this green construction while focusing on governmental policy implications such as green certificate for construction products. Green building has long been recognized as the leading green construction product and the green trends have expanded to infrastructure construction such as road construction. Therefore, this research concentrates on various green road certification processes in the United States in order to develop a framework for Korean green road certification. In doing so, some of the green roads application has also been analyzed. This research intends to provide background information for Korean green construction policies, especially on green road certification.
A Study on the Effective Standard Career Development Program for Construction Engineer
Kim, Sang-Bum ; Kim, Yong-Bi ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1181~1189
DOI : 10.12652/Ksce.2013.33.3.1181
This study illustrates the results of a background policy research conducted to provide supports for the `Korean Engineering Industry Enhancement Law` promulgated by the Korean Ministry of Knowledge Economy. The main issue covered in this study is an effective way of managing standardized career development program for construction engineers. This study attempted to provide detailed criteria and guidelines for the public career development program for construction engineers by effectively collecting and analyzing relative. In doing so, various opinions from a wide range of stakeholders and related parties were gathered. In addition, an in-depth benchmarking investigation was performed with four main associations who have been operating their own career development management program for construction engineers. Some of the findings from this study have played a positive role specifying the details of the recently promulgated law such as `Notice by Ministry of Knowledge Economy 2011-76: guidelines for managing construction engineer career`. This study was an empirical and practical research effort helping the government to set up an effective construction law system.
3D-based Earthwork Planning and CO
Emission Estimation for Automated Earthworks
Kim, Sung-Keun ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1191~1202
DOI : 10.12652/Ksce.2013.33.3.1191
The former researches on earthwork automation were mainly focused on GPS and sensor application, environment modelling, equipment path planning, work information management, and remote control etc. Recently, reducing
emission becomes one of main focuses for an automation research. In the case of earthwork operations, many kinds of construction machines or robots are involved, which can cause high level of
in a construction site. An effective earthwork plan and construction machine operation can both increase productivity and safety and decrease
emission level. In this research, some automation concepts for green earthworks are suggested such as a 3D construction site model, a 3D earthwork distribution based on two different earthwork methods, and an earthwork package construction method. A excel-based simulator is developed to generate the 3D earthwork distribution and to estimate the level of
emission for the given earthwork.
An Asset Management based Accounting Method for Sewer Maintenance Expenditure
Lee, Ju-Hyun ; Yun, Won-Gun ; Kim, Kyong Ju ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1203~1213
DOI : 10.12652/Ksce.2013.33.3.1203
Governmental accounting system has changed from budgetary accounting on the basis of cash and bookkeeping by single entry to financial accounting on the basis of accrual and bookkeeping by double entry. In the context of this transition, infrastructure becomes considered an asset in accounting, and resulting accounting methods also take different approaches from conventional budgetary accounting. Financial accounting system defines expenditures into two categories, i.e. capital expenditure(CAPEX) and operational expenditure(OPEX), and stipulates that the expenditure shall be divided into those two categories before accounting. The construction and expansion of infrastructure must be considered a CAPEX because it means a sort of asset acquisition, but with regard to applications in practical accounting, it is actually challenging to judge whether any expenditure associated with maintenance works (including repair and service) during use of infrastructure acquired shall be considered CAPEX or OPEX. This paper suggested an asset management based accounting method for sewer maintenance expenditure. And it applied the method to actual accounting cases and analyzed them in comparison with conventional financial information. As a case study result, Sewer asset value of S city increased approximately 700 hundred won because sewer maintenance expenditure are classified between OPEX and CAPEX according to the proposed accounting method. It is expected that the proposed accounting method will contribute significantly to providing any proper sewer asset value information.
A Study of the Combination Method for Earthwork Equipments Using the Environmental Loads and Costs
Kang, Min-Ho ; Park, Hyung-Keun ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1215~1224
DOI : 10.12652/Ksce.2013.33.3.1215
Great efforts have been made worldwide to reduce the Green House Gas (GHG) emission following the "Kyoto Protocol" declared during the United Nations Framework Convention on Climate Change in 1997. Many industries have restructured to meet the standard set by the Protocol. However, no clear guidance has been established for the purpose of reducing the GHG emission in construction industry. In addition, no significant effort has been made to conserve the energy during construction activities. For more effective energy saving in construction industry, it is essential to collect data about energy consumption, quantity of environmental emissions and costs. However, most studies on sustainable construction have been concentrated on the use of equipment, maintenance and repair works during construction due to the difficulties of collecting such data. This study suggests a method to select the most environmentally friendly equipment combination for earthwork with comparing environmental loads and costs using the database of Life Cycle Inventory in the Ministry of Knowledge Economy and Ministry of Environment of Korea.
A Study on the pattern of energy consumption of apartment in winter with Automatic Meter Reading Systems
Shin, Juho ; Kim, Hongseok ; Lee, Donghwan ; Park, Seunghee ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1225~1234
DOI : 10.12652/Ksce.2013.33.3.1225
According to the importance of greenhouse gas emissions, it grows day by day, the goverment is promoting to prepare the specific policy implementation to enhance building energy-saving design standars as the development agenda. In this study, the statistical analysis was performed by Descriptive statistics, Regression analysis, and Hypothesis testing to collect to generate and storage energy usage data in real time to settle parameter setting to affect energy consumption under energy-guzzling apartment not single building. This study is expected to be utilized as the basis for the optimum energy-saving design of the future of the building or facility energy costs rise and the demand for energy-efficient and stable management.
3D BIM-based Building Energy Efficiency Solution for Carbon Emission Reduction
Lee, Dong Hwan ; Kwon, Kee Jung ; Shin, Ju Ho ; Park, Seunghee ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1235~1242
DOI : 10.12652/Ksce.2013.33.3.1235
This study deals with the BIM (Building Information Modeling)-based energy performance analysis implemented in EnergyPlus. The BIM model constructed at Revit is updated at Design Builder, adding HVAC models and converted compatibly with the EnergyPlus. We can obtain the input values about HVAC system and building environment such as HVAC system efficient, the number of air changes and energy consumption of equipment on applying GAs (Genetic algorithms). After modification about HVAC system, Optimization about HVAC system energy consumption can be analyzed. In order to maximize the building energy performance, a genetic algorithm (GA)-based optimization technique is applied to the modified HVAC models. Throughout the proposed building energy simulation, finally, the best optimized HVAC control schedule for the target building can be obtained in the form of "supply air temperature schedule". Throughout the supply air temperature schedule is applied to energy performance simulation, we obtained energy saving effect result on simulation.
Influence of Initial Clamping Force of Tension Clamp on Performance of Elastic Rail Fastening System
Lee, Dong Wook ; Choi, Jung Youl ; Baik, Chan Ho ; Park, Yong Gul ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1243~1251
DOI : 10.12652/Ksce.2013.33.3.1243
The purpose of this study is to investigate the influence of initial clamping force of tension clamp on the performance of an elastic rail fastening system used in sharp curve track. In this study, the initial clamping force and the increasing lateral wheel loads were conducted in the analytical and experimental study, i.e., finite element analysis, laboratory and field test. Using the analytical and experimental results, the performance of the tension clamp was investigated. It was found that the stress of tension clamp depends on the initial clamping force. Therefore the initial clamping force appeared to directly affect the compression stress of the tension clamp. It was found that the compression stress of tension clamp was transferred to the tensile stress by applied the lateral wheel load in service sharp curve track. Further, it was concluded that the initial clamping force was applied on the strengthening force for the tension clamp and then the appropriate initial clamping force was important to ensure a stable performance and long term endurance of tension clamp.
Lessons Learned from Eco-town Cases for Sustainable Development
Chang, Hoon ;
Journal of The Korean Society of Civil Engineers, volume 33, issue 3, 2013, Pages 1253~1260
DOI : 10.12652/Ksce.2013.33.3.1253
Eco-town development projects have often prevailed throughout the World to initiate the new form of sustainable development plans. As a future development type, the eco-town project shares underlying notions with sustainable development, which has been recently revised into a wider definition; (i) energy efficiency, (ii) climate adaptation, and (iii) socio-economic development. There are four types of eco-town projects based on its characteristics and aims depending on project sites, regions, or countries. This paper tried to demonstrate the types of eco-town projects and summarizes its strategy plans from each type. Many eco-town cases can be placed in one of types, however there cannot be strictly discrete classification by its complicated and composite characteristics of them. In conclusion, the analyzed types can be a useful strategy plan for pursuing further eco-town projects in domestic as well as in international regions.