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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 19, Issue 3_6 - Nov 1999
Volume 19, Issue 2_6 - Nov 1999
Volume 19, Issue 1_6 - Nov 1999
Volume 19, Issue 3_5 - Sep 1999
Volume 19, Issue 2_5 - Sep 1999
Volume 19, Issue 1_5 - Sep 1999
Volume 19, Issue 3_4 - Jul 1999
Volume 19, Issue 2_4 - Jul 1999
Volume 19, Issue 1_4 - Jul 1999
Volume 19, Issue 3_3 - May 1999
Volume 19, Issue 2_3 - May 1999
Volume 19, Issue 1_3 - May 1999
Volume 19, Issue 3_2 - Mar 1999
Volume 19, Issue 2_2 - Mar 1999
Volume 19, Issue 1_2 - Mar 1999
Volume 19, Issue 3_1 - Jan 1999
Volume 19, Issue 2_1 - Jan 1999
Volume 19, Issue 1_1 - Jan 1999
Selecting the target year
The Applicabilities of Local Scour Equation at Bridge Piers
Choi, Gye-Woon ; Seo, Byung-Ha ; Kim, Dong-Wook ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 653~653
In this paper, the applicabilities of the local scour equations at bridge piers are observed through the comparison with the field data. The field data of two hundred and seventy-two in the world are collected for the comparison. Among them, the nine data records is beyond deeper than 7 m in scour depth. Sixteen equations, which are named as Chitale, Laursen, Bata, Ahmad, Larras, Neill, Bruesers, Hancu, Shen-Karaki I, Shen-Karaki II, Shen-Karaki III, Coleman, CSU, Basak-Basmily-Ergun, Raudkivi & Ettema, Froehlich equations, are tested for the comparison with the field data. Through the comparison between the computational results using the equations and the field data, it is indicated that CSU and Froehlich equations are applicable for computing the local scour at bridge piers in large streams and/or rivers. However, Laursen, Neill and Bruesers equations including two equations can be applied for the local scour at bridge piers installed in small streams. At the same time, the other 11 equations are not properly suitable for predicting the local scour at bridge piers in streams and/or rivers. Using the results of this paper, the more reasonable scour depths at bridge piers can be predicted.
Development and Application of Rating Curves for the Keum River
Yoo, Ju-Hwan ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 665~665
Evaluation of river discharge is a fundamental basis for the use of water resources as well as flood control. In the past, many rating curves was developed with its individual purposes. Now measuring the discharges and developing their stage-discharge curves every year is performed by the authorities related with the planning and management of water resources such as the Ministry of Constructions and Transportation, Korea Water Resources Corporation, Rural Development Corporation etc. These rating curves are not prudently developed based on the hydraulics of the flow control in the stream, data filtering, and the regionalization. Consequently their reliabilities are sometimes limited in the application. With these considered and studied, new rating curves at the four major gaging stations of the Keum river were developed. Then the application of the products were tested and compared with the previous on the relation between specific discharge vs. catchment area.
Hydraulic Properties of Concrete Block of Uniform Roughness Height for Bed Protection
Paik, Joong-Cheol ; Choi, Sung-Uk ; Cho, Won-Cheol ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 677~677
G-blocks are concrete blocks designed to be paved around the bridge piers in order to protect the channel bed from local scour. The surface of G-blocks is corrugated with uniform roughness height to provide the bottom with increased shear force. For G-blocks to perform their role successfully, hydraulic resistance by the G-blocks should not be different from other parts of the channel. Furthermore, they should be safe against the flow force. In this study, hydraulic properties of G-blocks as a countermeasure for local erosion are investigated through laboratory experiments. Flume experiments show that resistance by G-blocks is mainly dependent on the placement angle of the salient to flow direction. Both semi-logarithmic and power law relationships can be applied to intermediate scale roughness by G-blocks. Manning-Strickler's relationship derived from the power law equation shows that the roughness characteristics of G-blocks are similar to those of natural channels. Furthermore, safety index of the G-blocks is derived in terms of Reynolds number for an individual block and group of interlocked blocks.
Hydraulic Model Test for Simulating the Characteristics of Water Circulation in the Masan Bay
Oh, Young-Min ; Ahn, Hee-Do ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 687~687
The Chinhae Masan Bay polluted severely has been studied for a long time by many researchers to clean it up, using the field test, numerical modelling and hydraulic model test. In the present study the characteristics of water circulation was simulated by the hydraulic model test to make a plan to reduce the water pollution in the Masan Bay. The drogue and current velocity test in the field were done and the tide generation system was setup to simulate the flow pattern in the field. From the experimental results with the semi-diurnal tide, the M2 tidal elevation measured in the laboratory showed a good agreement with target elevation. The current was measured at three points in the model bay with 2-D EM (Electro-Magnetic) sensors and showed a good agreement with the filed data as well, while dye diffusion tests were conducted near both Somodo and waste water outfall respectively to investigate the diffusion pattern. The dye was diffused slowly during flood tide but quickly during ebb tide showing a good agreement with the filed data.
Dispersion Correction of 2-D Finite Difference Model for Tsunami Propagation over Slowly Varying Topography
Yoon, Sung-Bum ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 695~695
A leap-frog scheme for shallow water equations has been widely employed in most of finite difference numerical models for the simulation of tsunami propagation. This scheme gives a correct dispersion effect for uniform water depth, if the grid size is properly selected. However, if the water depth changes, the dispersion effect can not be accurately kept in the whole computational domain. In this study a new 2-dimensional finite difference numerical scheme is developed to satisfy locally the physical dispersion for slowly varying topography. The new scheme uses an imaginary grid to satisfy dispersion relationships of tsunami for a given water depth and time step, and also uses the variables at the imaginary grid point by interpolating them at neighboring points. The accuracy of the numerical scheme developed in this study is tested by comparing the present numerical results for an initial Gaussian hump with analytical solution and other numerical results reported earlier.
Bragg Reflection of Water Waves over Sinusoidally Varying Topographies
Cho, Yong-Sik ; Kim, Chang-Wan ; Lee, Jong-In ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 705~705
The Bragg reflection of monochromatic waves propagating over sinusoidally varying topographies is theoretically investigated. A singly-sinusoidally varying topography is first represented by a finite number of small steps. The eigenfunction expansion model is then used to calculate reflection coefficients. The model is also applied to the study of Bragg reflection of monochromatic waves over doubly-sinusoidally varying topographies. The calculated reflection coefficients are compared with available numerical solutions and laboratory measurements. A reasonable agreement is observed.
Characteristics of wave Forces Acting on the Seawater Exchange Breakwater
Lee, Dal-Soo ; Oh, Young-Min ; Lee, Chang-Hoon ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 711~711
As a means of water quality improvement in the severely contaminated bay the seawater exchange breakwater was developed to allow water outside the bay to flow into the bay. Horizontal and uplift wave force were measured by a 3-component load cell to investigate whether the breakwater is safe against the wave action prior to the function of water exchange. As results, it was verified that the seawater exchange breakwater suggested in this study is safer than the conventional solid wall caisson breakwater by reducing the wave forces acting on the breakwater.
A Study on Nonlinear Wave Forces and Wave Transformations of Multi-Vertical Cylinders with Arbitrary Cross Section
Kim, Do-Sam ; Shin, Dong-Hoon ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 717~717
In this study, a nonlinear frequency domain method, based on the perturbation and boundary integral methods, is presented in order to evaluate the nonlinear wave forces and wave transformations of multi-vertical cylinders with arbitrary cross section. Verification of present numercial solutions is confirmed by comparing with Murakami et al.'s(1993) numercial and experimental results for one vertical cylinder with circular cross section, and Masuda et al.'s(1986) ones using Haskind method for two cylinders with the same cross section. Therefore, this numercial method is applied to the three vertical cylinders to discuss their nonliner wave forces and wave transformations according to the variations of incident wave period and different cross section types of vertical cylinders.
Influence of C/N ratio on the Denitrification using Fluidized Biological Activated Carbon
Kim, Duk-Jin ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 729~729
This study was investigated the influence of C/N ratio on the denitrification using fluidized bed reactor. Experiment operated at influent COD/N ratio of 3.0, 5.0, 7.06, 8.0 and 10.0 with five columns, maintained at 20minute of empty bed contact time (EBCT). The influent COD/N ratio controlled by exchanging of saccharouse concentration was used external carbon source as electron donor, but the supplying nitrate nitrogen concentration was maintained at 20 mg/L for each column. In the range of influent COD/N ratio were less or more than 7.06, stoichiometrical COD/N ratio, the activity of denitrifying bacteria was decreased. The number proportion of denitrifying bacteria in hetrotrophic bacteria declined with increasing of (COD/N) in ratio. At the influent COD/N ratio was less than 7.06, nitrite nitrogen was accumulated 58 times of the one at 7.06. At the COD/N ratio was less than 7.06, the (COD/N)u ratio was lower than the stoichiometrical COD/N ratio. At the COD/N ratio was more than 7.06, (COD/N)u was higher than the stoichiometrical COD/N ratio.
Anaerobic Pretreatment of Brewery Wastewater
Ahn, Young-Ho ; Min, Kyung-Sok ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 737~737
In this paper, experiences with a full-scale UASB reactor as the anaerobic pretreatment of the wastewater in the brewery industry, specifically Oriental Breweries (OB) of Kumi, Korea, are presented. The given example shows that an anaerobic sludge blanket reactor can be used as the anaerobic pretreatment process of brewery wastewater. It is also possible to run the anaerobic pretreatment during the overall operating periods even with low wastewater concentrations (average COD 1,400 mg/L) and less flow rate than specified by design parameters. Over the years, the average COD removal efficiency in the UASB reactor is over 80%. Further more it is shown that the running expenses of the anaerobic pretreatment of industrial wastewater are very low. However, excessively long retention time in UASB system during the overall operating periods was detrimental for sludge pelletisation. In addition, it was often necessary to reseed the pelletized sludges due to the washout of sludge from the pre-acidification reactor and the UASB reactor. Although this situations did not lead a failure of system, it emphasizes that process configuration and operational condition were important parameters for sludge pelletisation. The full-scale and lab-scale research reveal that in process design, a completely mixed type pre-acidification reactor before discharge to the UASB-reactor is not advisable.
Construction and Application of Database System for Life Cycle
Assessment of Building
Seo, Seong-Won ; Hwang, Yong-Woo ; Ichinose, Toshiaki ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 749~749
In proportion to the world population increase, global environmental problems including ozone depletion, global valuing are getting larger. One of the largest global environmental problems facing the most nations in the world is global warming. Among the gases caused the global warming, the
is the one of the main factors causing a global warming problem. In this paper, a LCA (Life Cycle Assessment) tool was developed to calculate the
emission from each building in Korea. This tool is based on the database of each stage (manufacturing of building materials, construction, operation, demolition and final disposal) of building. This tool helps practitioners and designers for which is enabled the calculation of life cycle
for ecodesign of buildings. Using the developed tool, it was calculated the
emission from apartment (total building floor area
, 60 households, central heating system) during the life cycle as an application case study. As results, total
emission was 1,846.3 T-C during the year of 20 years. The
emission in the construction was 336.7 T-C having 18.24% of total
emission throughout the life cycle was mostly due to the operation having 80.42% (1,484.8 T-C) of total
Advanced Oxidation Technology for 2,4-Dichlorophenol by Fenton's Reagents
Shin, Hang-Sik ; Nam, Se-Yong ; Lim, Jae-Lim ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 757~757
Advanced oxidation technologies for wastewater treatment are gaining more importance since biological processes are often not sufficient for toxic or biorecalcitrant compounds. Fenton oxidation using combination of hydrogen peroxide as an oxidant and iron ion as a catalyst for the treatment of 2,4-dichlorophenol (2,4-DCP) was investigated in this study. Hydrogen peroxide catalytic oxidation was effective at pH 4.0, while the removal efficiency of 2,4-DCP using buffer system at the same pH was extremely low because of the reaction with hydroxyl radical and buffer component as a scavenger. In catalytic efficiency concerning oxidation state of iron ion, the
system was more effective than the
system. The optimum ratio of dosage of oxidant and catalyst was
. The order of removal efficiency according to the reagents feeding mode was batch mode > semi-batch mode > continuous mode, however, the total removal efficiencies of 2,4-DCP in the extended reaction time were reached at the same level in three modes.
Electrochemical Oxidation of Tannery Wastewater in an Activated Carbon Cell Reactor
Park, Soon-Kil ; Kim, Young-Ju ; Min, Kyung-Sok ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 763~763
Electrochemical-oxidation of the tannery wastewater using a packed activated carbon cell was investigated. In the reactor, platinized anode and 316 L cathode are installed and activated carbons are filled. Sodium chloride (NaCl) was used as an electrolyte. Organic matters and ammonium elimination were influenced by concentration of chloride, electrical density and negatively influenced by the presence of organic compounds. Ammonium elimination efficiency after 15 min of electrolysis at a current density of
and chloride concentration of 11,000 mg/l was equal to about 99.5%. After electrolysis, BOD of waste water were increased i.e. influent SBOD of 4.3 mg/l increased to about 28.4 mg/l in the final effluent. The removal efficiencies of chemically and biologically treated wastewater were better, i.e. about twice than the only chemically pretreated tannery wastewater. Electrooxidation using packed activated carbon cell proved more efficient, i. e. about 50% than the conventional electrical oxidation system. Augmentation of water temperature in reactor was inversely proportional to the concentration of chloride. In conclusion, electrochemical oxidation system can be used as a polishing step for the biological effluent of tannery wastewater treatment.
Realtime Prediction of Residual Chlorine Concentration in Water Distribution Network Using Artificial Neural Network
Ha, Sung-Ryong ; Park, Sang-Young ;
Journal of The Korean Society of Civil Engineers, volume 19, issue 2_6, 1999, Pages 773~773
This paper developed an artificial neural network (ANN) model for real-time prediction of residual chlorine concentration in water distribution system. The multi-layered ANN model, which has input, hidden, and output layer, was employed. The sensitivity analysis was conducted for training iteration. hidden-layer-node, input parameters, and prediction steps respectively and the optimal model structure was simulated. The result of training error according to the iteration number was not significant when the number of iteration was greater than 100 times. For node number in hidden layer, the model that has 2.5 times as many as the input parameters showed best result. The validation results for input parameter combination showed better result when downstream information used only than other cases, which means that the right before time's residual-chlorine-concentration has significant influence on the present concentration. The effect of chlorine dosage, which is adjusted by a day base, was not significant to an hour based prediction model. With the combination of up and down stream conditions, simulated results were good till 3 hours ahead that was being in travel time of chlorine substance in pipe network studied.