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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
Study on Combined Use of Inclination and Acceleration for Displacement Estimation of a Wind Turbine Structure
Park, Jong-Woong ; Sim, Sung-Han ; Jung, Byung-Jin ; Yi, Jin-Hak ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 1~8
DOI : 10.12652/Ksce.2015.35.1.0001
Wind power systems have gained much attention due to the relatively high reliability, good infrastructures and cost competitiveness to the fossil fuels. Advances have been made to increase the power efficiency of wind turbines while less attention has been focused on structural integrity assessment of structural sub-systems such as towers and foundations. Among many parameters for integrity assessment, the most perceptive parameter may be the induced horizontal displacement at the hub height although it is very difficult to measure particularly in large-scale and high-rise wind turbine structures. This study proposes an indirect displacement estimation scheme based on the combined use of inclinometers and accelerometers for more convenient and cost-effective measurements. To this end, (1) the formulation for data fusion of inclination and acceleration responses was presented and (2) the proposed method was numerically validated on an NREL 5 MW wind turbine model. The numerical analysis was carried out to investigate the performance of the propose method according to the number of sensors, the resolution and the available sampling rate of the inclinometers to be used.
Interface Behavior of Concrete Infilled Steel Tube Subjected to Flexure
Lee, Ta ; Jeong, Jong-Hyun ; Kim, Hyeng-Ju ; Lee, Yong-Hak ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 9~17
DOI : 10.12652/Ksce.2015.35.1.0009
Interface behavior of concrete-infilled steel tube (CFT) was investigated based on the experimental observations and numerical analyses. Laboratory tests were performed for twelve CFTs that consisted of two different cases of diameters where each diameter case was composed of three different cases of shear span length. Thereby, diameter and shear span parameters were considered to prove the question of whether there exists interface slip between steel tube and infilled-concrete. Confining effect of steel tube to infilled concrete was also investigated by measuring lateral strain as well as longitudinal strain. Based on the study, it was concluded that confining effect of steel tube to infilled-concrete is not influential under flexural loading and therefore, the sectional analysis is an effective way to estimate the flexural strength of CFT.
Crack Width Control on Concrete Slab using Half-Depth Precast Panels with Loop Joints
Kim, Dong Wook ; Shim, Chang Su ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 19~29
DOI : 10.12652/Ksce.2015.35.1.0019
As the half-depth precast concrete decks are increasingly applied to the construction sites, researches on connection details have been increased. For design of concrete bridge deck with half-depth precast panels, it is required to provide appropriate details of transverse loop joints between panels. In this paper, the structural performance of precast decks was evaluated to investigate continuity of the proposed loop joint details. From the results, the validity of the joints for the continuity of deck was observed in the aspect of flexural strength and crack control. The ultimate strength increased 1.52 times as the reinforcement spacing in the joint was reduced. In terms of crack control, direct crack width calculation for the loop joint showed appropriate results comparing with measured crack width.
Analysis of Load Carrying Capacity of Bridges Based on Field Data with Serviced Time
Kyung, Kab Soo ; Lee, Yeong Il ; Lee, Sung Jin ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 31~38
DOI : 10.12652/Ksce.2015.35.1.0031
In this paper, change of load carrying capacity of bridges with time was analyzed referring to the safety inspect data stored in the KISTEC. From this study, it was known that the capacity is rated differently by various parameters such as inspector`s subjective. Accordingly, an improved method, in this paper, is suggested which can correct deviation due to several uncertainties involved in rating process. The suggested method can be utilized for efficient maintenance of bridges such as cycles and determination of priority of retrofit, and estimation of service life etc.
Experimental and Analytical Study on the Fracture Strength of RC Beams Strengthened for Flexure with GFRP Involving the Debonding of FRP Reinforcement
Lee, Jong-Han ; Kwon, Hyuck Bae ; Kang, Su Tae ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 39~48
DOI : 10.12652/Ksce.2015.35.1.0039
Reinforced concrete (RC) structures strengthened with FRP materials would cause the loss of the reinforcing effect and the sudden failure of the structure due to the debonding of FRP. The debonding fracture strength of the FRP-strengthened concrete structures has been evaluated using the same strength method as applied in RC structures based on the debonding strain of FRP. However, the values of the FRP debonding strain are different according to design guidelines. Thus, this study carried out an experimental study on RC beams reinforced with GFRP and evaluated the debonding fracture strength of the strengthened beams from each design guideline. Since the debonding failure occurs prior to reaching the ultimate value of concrete compressive strain, this study accounts for the nonlinear stress distribution of concrete. This study also proposed equations that can evaluate the debonding strength of GFRP-strengthened RC beams with similar safety to the ultimate flexural strength of non-strengthened RC beams.
Performance Assessment for Rockfall Protection Systems II: Performance Assessment
Kim, Kee Dong ; Ko, Man Gi ; Kim, Dal Sung ; Han, Ki Jang ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 49~61
DOI : 10.12652/Ksce.2015.35.1.0049
This is the second of two companion papers that describe the performance assessment for flexible rockfall protection systems. Described in a companion paper is the criteria to assess the performance of flexible rockfall protection systems. In this study the performance assessment of domestic rockfall protection fences was implemented using the criteria suggested in the companion paper. It was investigated that the rockfall protection fences for express highways performed well to resist the rockfall energy of 50kJ and the deformed rockfall protection fences right after impacting would not obstruct the vehicle traffic. However, to dissipate the rockfall energy of 50kJ with the level of European standards constantly, the spacing of wireropes was adjusted to be 200mm up to the 8th wirerope from the bottom and spacing-maintainers should be extended to the 8th wirerope. It was figured out that the rockfall protection fences for general highways were required to install spacing-maintainers as those for express highways because they, which did not have spacing-maintenance members, were very prone to the penetration of rockfall even for the very small rockfall impact energies.
Performance Assessment for Rockfall Protection Systems I: Performance Assessment Criteria
Kim, Kee Dong ; Ko, Man Gi ; Kim, Dal Sung ; Moon, Byung Gab ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 63~76
DOI : 10.12652/Ksce.2015.35.1.0063
The purpose of this study is to suggest performance levels, a test method, and assessment criteria for the performance assessment to allow standardized tests for rockfall protection systems. The range of rockfall impact energy was determined by using domestic rockfall data and a total of 9 performance levels from 50kJ to 1500kJ were suggested. The performance assessment is implemented by two types of full-scale free-fall impact tests to investigate the serviceability and the maximum capacity as in European and American standards. It was considered to be reasonable that the specimens of rockfall protection systems consist of 3 spans and the concrete block of a polyhedron with 26 faces, similar to spheres, impacts at the center of a center span. Assessment criteria were constructed to investigate whether a rockfall penetrated rockfall protection systems and whether the deformed specimen encroached on the roadway or obstructed the vehicle traffic.
A Comparison of Residual Tensile Properties of GFRP Reinforcing Bar at High Temperature and after Exposure to High Temperature
Kim, Seongdo ; Moon, Doyoung ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 77~84
DOI : 10.12652/Ksce.2015.35.1.0077
Tensile tests were conducted on the GFRP reinforcement exposed to high temperature. The exposure condition for this study was below
for about 3 minutes. This conditioning is minor compared with that presented in experimental program conducted by other researchers. The residual tensile strength and elastic modulus of GFRP reinforcing bars at high temperature and after exposure to high temperature were compared. In results, tensile properties were decreased at high temperatures, but those after exposure to high temperature were recovered to pre-heating level almost completely. These results could be valuable for evaluating GFRP reinforced structure damaged by fire accident.
Shear Behavior of Web Element in PSC Beams Incorporated with Arch Action
Jeong, Je Pyong ; Shin, Geun Ock ; Kim, Woo ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 85~92
DOI : 10.12652/Ksce.2015.35.1.0085
It is well known that axial tension decreases the shear strength of RC & PSC beams without transverse reinforcement, and axial compression increases the shear resistance. What is perhaps not very well understood is how much the shear resistance capacity is influenced by axial load. RC beams without shear reinforcement subjected to large axial compression and shear may fail in a very brittle manner at the instance of first diagonal cracking. As a result, a conservative approach should be used for such members. According to the ACI Code, the shear strength in web is calculated by effect of axial force and the vertical force in the stirrups calculated by
truss model. This study was performed to examine the effect of axial force in reinforced concrete beams by nonlinear FEM program (ATENA-2D).
Design of Economical Steel Ratio in RC Flexural Members
Jeong, Je Pyong ; Lee, Chang Kee ; Ryu, Heui Joong ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 93~99
DOI : 10.12652/Ksce.2015.35.1.0093
This paper is on a practical method for determination of the economical steel ratio in RC flexural members with an equal safety factor. The cost functions of each material and labor are considered to construct the cost function. Then, an equation for determination of the economical flexure steel ratio with the lowest construction cost were proposed. It was found that a relevant steel ratio is recommended to be 0.65~1.0% for designing singly reinforced rectangular beam.
Shear Strain Big-Bang of RC Membrane Panel Subjected to Shear
Jeong, Je Pyong ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 101~110
DOI : 10.12652/Ksce.2015.35.1.0101
RC panels were tested under in-plane pure-shear monotonic loading condition using the Panel Element Tester by Hsu (1997, ACI). By combining the equilibrium, compatibility, and the softened stress-strain relationship of concrete in biaxial state, Modern Truss Model (MCFT, RA-STM) are capable of producing the nonlinear analysis of RC membrane panel through the complicated trial-and-error method with double loop. In this paper, an efficient algorithm with one loop is proposed for the refined Mohr compatibility Method based on the strut-tie failure criteria. This algorithm can be speedy calculated to analyze the shear history of RC membrane element using the results of Hsu test. The results indicate that the response of shear deformation energy at Big Bang of shear strain significantly influenced by the principal compressive stress-strain (crushing failure).
Influence of Spatial Rainfall Distribution on Sediment Yield: An Experimental Study
Shin, Sanghoon ; Kim, Won ; Lee, Seungyub ; Paik, Kyungrock ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 111~117
DOI : 10.12652/Ksce.2015.35.1.0111
We investigate the influence of spatial rainfall distribution on hillslope soil erosion through laboratory experiments. Two distinct spatial distributions are examined in this study, i.e., rainfall concentrated on central area versus upper area of hillslope. During the entire period of 8 hours for each experiment, direct runoff, subsurface flow, and sediment yield are measured at high temporal resolution (10 minutes). Compared to the case that rainfalll concentrated on central area, upstream concentrated rainfall results in lower peak of the sediment yield curve while greater cumulative sediment yield. Cumulative sediment yield increases over time linearly but its growth rate shows a sudden decrease at around 2 hours. This should be taken into consideration when temporal variability of sediment yield is estimated from observed total amount, and demonstrates the necessity of measuring sediment yield at high temporal resolution.
Wave Pressure Characteristics of Pile-Supported Breakwater with the Horizontal Slit Walls
Ko, Kwangoh ; Pack, Seungwoo ; Park, Changbeom ; Lee, Jong-In ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 119~128
DOI : 10.12652/Ksce.2015.35.1.0119
This study investigates the wave pressure characteristics of the pile-supported breakwater with single or double perforated walls through 2-D hydraulic experiments and the measured wave pressures are compared to those of wave pressures by Goda`s formula. For single chamber, the measured wave pressures in the front wall and rear wall decreased to about 25% and 30%, respectively, compared to those of wave pressures by Goda`s formula. Also, the decrease in the wave pressures for double chamber were about 27%, 53%, and 64% in the front wall, middle wall, and rear wall, respectively. It was found that the pile-supported breakwater with double perforated walls was more efficient than the single chamber due to wave dissipation effects of double slit walls with horizontal slits.
A Study on the Face Slab Deformation of Concrete Faced Rockfill Dams During Initial Impoundment
Won, Myoung Soo ; Kim, Hyeong Joo ; Jung, Young Chae ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 129~139
DOI : 10.12652/Ksce.2015.35.1.0129
Concrete-Face Rock-Fill Dams (CFRDs) are rock-fill dams with watertight-concrete slabs on its upstream slope instead of its central earth cores. The design for CFRDs are still largely empirical and typically based on past experiences. This paper presents a description of the concrete face slabs and leakage behaviors of two post-constructed CFRDs based on the data gathered through instrumentation during the initial impoundment. The results show that the strain on the concrete face slab and the horizontal displacements of the vertical slab joints are slightly affected by both the seasonal temperature change and water loading during the initial impoundment. The deformation of perimetric joints are less affected by the temperature change, however it is significantly affected by the water loading during the initial impoundment. The leakage rate is significantly affected by the hydrostatic load and the deformation of the perimetric joints.
Estimation of Shear Wave Velocity of Rockfill Zone by Dynamic Analysis using Micro-earthquake Records
Ha, Ik Soo ; Lee, Soo Gwun ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 141~152
DOI : 10.12652/Ksce.2015.35.1.0141
The objective of this study is to estimate shear wave velocity of rockfill materials by making practical use of the micro-earthquake records which are ordinarily obtained at a domestic rockfill dam and to verify its applicability. Micro-earthquake records were obtained at the site of Heongseong dam and Soyanggang dam, which are the existing multi-purpose dams in Korea. In the previous study, the fundamental periods of each dam were already evaluated by analyzing the response spectrum of the observed records. In this study, numerical analyses varying shear moduli of rockfill zone were carried out using the acceleration histories measured at the abutment as input ground motions. From comparison between the fundamental periods calculated by numerical analyses and measured records, the shear wave velocities with depth were estimated. It is found that the effect of different earthquake events on shear wave velocity estimation for the target dam materials is negligible and the shear wave velocity can be consistently evaluated. Furthermore, comparing the shear wave velocity with the previous researchers` empirical relationships and field test results, applicability of suggested method is verified. Therefore, in case that it is impossible to conduct field tests and estimation is preliminary, the suggested method can be practically used.
Design of Mat Foundation by Simplified Flexible Method Using Regression Analysis
Moon, Kyoungtae ; Park, Sangyeol ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 153~164
DOI : 10.12652/Ksce.2015.35.1.0153
The methods of design of mat foundation may be classified as the rigid method and the flexible method according to the assumptions used. In the rigid method, the mat is assumed to be infinitely rigid and the contact pressure is assumed planar distribution. However, the contact pressure is not planar but curved surface because the real mat is not rigid. Therefore, it is not precise to analyze the mat foundation using the rigid method, and so there is no choice but to accept an error. On the other hand, in the flexible method, the mat is considered as the plate on the elastic foundation. This elastic plate theory is for the infinite plate acting a concentrated load on the elastic foundation. However, the functions for the moment, shear, and the deflection by the flexible method are very complex, there are many difficulties for the designer to use them. Also, it is impossible to use the design aid figures as a substitute of the complex functions, because they do not cover the values at the critical sections for the moment and shear. Therefore, in this research, the simplified functions for the moment, shear, and the deflection are proposed by regression analysis for an designer to use easily the flexible method. The simplified functions are very accurate and very ease to use.
Implementing AHP of Railway Design Model
Shin, Youngho ; Kim, Jeong Hyun ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 165~172
DOI : 10.12652/Ksce.2015.35.1.0165
The appropriateness of railway route design is generally evaluated by the future value corresponding to the travel demand or benefit-cost analysis. These methods may have the limitation for the reasons that all the design alternatives cannot be considered, and the differentiation between the alternatives may not be significant because the alternatives are based on the strict basic scheme such as the design criteria. In addition, the cost varies by the design elements. In this study, all the design alternatives are considered with the automatized tool and the design criteria, and evaluated with the multi-criterion decision making method. The weight for each design element with the analytic hierarchical process may be helpful to derive more efficient railway alignment.
Study on Influencing Factors of Traffic Accidents in Urban Tunnel Using Quantification Theory (In Busan Metropolitan City)
Lim, Chang Sik ; Choi, Yang Won ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 173~185
DOI : 10.12652/Ksce.2015.35.1.0173
This study aims to investigate the characteristics and types of car accidents and establish a prediction model by analyzing 456 car accidents having occurred in the 11 tunnels in Busan, through statistical analysis techniques. The results of this study can be summarized as below. As a result of analyzing the characteristics of car accidents, it was found that 64.9% of all the car accidents took place in the tunnels between 08:00 and 18:00, which was higher than 45.8 to 46.1% of the car accidents in common roads. As a result of analyzing the types of car accidents, the car-to-car accident type was the majority, and the sole-car accident type in the tunnels was relatively high, compared to that in common roads. Besides, people at the age between 21 and 40 were most involved in car accidents, and in the vehicle type of the first party to car accidents, trucks showed a high proportion, and in the cloud cover, rainy days or cloudy days showed a high proportion unlike clear days. As a result of analyzing the principal components of car accident influence factors, it was found that the first principal components were road, tunnel structure and traffic flow-related factors, the second principal components lighting facility and road structure-related factors, the third principal factors stand-by and lighting facility-related factors, the fourth principal components human and time series-related factors, the fifth principal components human-related factors, the sixth principal components vehicle and traffic flow-related factors, and the seventh principal components meteorological factors. As a result of classifying car accident spots, there were 5 optimized groups classified, and as a result of analyzing each group based on Quantification Theory Type I, it was found that the first group showed low explanation power for the prediction model, while the fourth group showed a middle explanation power and the second, third and fifth groups showed high explanation power for the prediction model. Out of all the items(principal components) over 0.2(a weak correlation) in the partial correlation coefficient absolute value of the prediction model, this study analyzed variables including road environment variables. As a result, main examination items were summarized as proper traffic flow processing, cross-section composition(the width of a road), tunnel structure(the length of a tunnel), the lineal of a road, ventilation facilities and lighting facilities.
A Study on Relevant Range of Vertical vertical grade at Urban Intersections
Yoon, Byoung-Jo ; Jung, Jae-Hoon ; Kim, Jin-Han ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 187~192
DOI : 10.12652/Ksce.2015.35.1.0187
In general, design of urban intersections are fundamentally different from rural intersections, but current urban intersection design has been appled to rural standards. This study has suggested the design standard for urban intersection grades based on the existing literature, field investigating and comparative analysis. Moreover, this study analyzes and compares the differences between urban and rural intersections, and intersections have been derived by appropriate design standards after reviewing the domestic and international grades design criteria. Site survey was performed to validate the derived design criteria by analyzing statistically to establish the design standards. Results were produced for the intersection portion grade standards by comparing the number of instructions which produced appropriate slope degree from 2.5% to 3% in normal condition and slope can be extended to 5% in some critical cases. In-situ investigation was performed to validate the produced data where slope was found from 0.0~8.6%. Additional data of accident analysis were also collected for the validation of the suggested data and correlation analysis was performed using the SPSS tool. Data were analyzed statistically using 95% significance level for vehicle-to-vehicle collided, head-on collision accident rates, where accident rates significantly correlated with the grade. Therefore, appropriate grade at the intersection should be designed and applied in order to reduce the number of accidents at the intersection. Finally, appropriate grades for urban intersections are suggested from 1-3% for normal cases and grades could extend up to 5% for unavoidable cases where extra care must be taken when designing.
Interaction Analysis between Construction Business Indicators and Business Performance Indicators of Specialty Contractors Depending on Operation Types
Kim, Nam-Sik ; Lee, Dong Wook ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 193~202
DOI : 10.12652/Ksce.2015.35.1.0193
This study suggests strategies business strategies of specialty contractors by interaction analysis between business performance indicators and construction business indicators depending on operation types. To analyzing this research, a database was analyze for construction orders and business performance indicators for specialty contractors with KRW 7 billion from 1997 to 2010 yr. For organized management oriented specialty contractors, the amount of construction orders is directly affecting the corporate stability and therefore decreasing orders can negatively affect the owner`s equity ratio. However, considering that the turnover ratio of total liabilities and net worth is affecting the owner`s equity, an asset management plan needs to be established in a way to increase sales to the owner`s equity secured with increase in construction orders. For a single leader oriented specialty contractors, the owner`s equity ratio is also significantly affected by change in the amount of construction orders and some countermeasure is required. But, as liability ratio is affecting the amount of construction orders, some sort of countermeasures to decrease liability ratio is required.
A Study on Classifications and Characteristics of Declined Rural Area in Chungcheong Region
Jo, Jin-Hee ; Park, Hyung-Keun ; Mo, Hye-Ran ; Lee, Han-Soo ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 203~215
DOI : 10.12652/Ksce.2015.35.1.0203
The study aims to identify the degree and types of spatial recessions in Si/Gun and Eup/Myun units within Chungcheong region in South Korea to contribute to the efforts being made to diagnose the rural recession and the potentials. To this end, we analyzed 27 Sis and Guns to identify the degree of recession and potentials of rural areas in Chungcheong region. We also carried out the diagnosis and K-Means Clustering on 274 Eups and Myuns, smaller administrative units, to figure out the types and characteristics of the rural recessions. In case of the analysis targeting the Sis and Guns, a relatively high degree of rural recession was found in Cheongyang, Seocheon and Taean for Chungcheongnam-do, and in Danyang and Goisan, as well as in Boeun, Okcheon and Youngdong - which are collectively called as `Southern 3 Areas in Chungcheongbuk-do` as they are conventionally known by their high degree of rural recession. According to the results of the clustering analysis carried out on the 166 Eups and Myuns, there were five outstanding clusters. They were; areas with housing deterioration (29), areas with poor economic foundation (16), areas with poor accessibility to central areas (42), areas with poor residential environment (51) and areas with aged population (28). The findings and results of the present study are likely to serve as a basis for the design and enforcement of forthcoming rural area activation policies. Also, it would be highly recommended that a more comprehensive diagnosis is taken from a community-level perspective and policy suggestions and strategies tailored for rural communities are further discussed.
Comparative Analysis between GDP Deflator Method and Index Adjustment Rate Method on BTL Sewer Rehabilitation Projects in Jeju
Yang, Du-Suck ; Lee, Dong Wook ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 217~227
DOI : 10.12652/Ksce.2015.35.1.0217
This study conducted case studies in order to suggest the improvement of GDP (Gross Domestic Product) deflator method which is adopted on calculating fluctuation rate on BTL (Build-Transfer-Lease) sewer rehabilitation projects in Jeju. As a result, because GDP deflator method calculates fluctuation rate by each quarterly, the fluctuation rate of GDP deflator method is higher than it of index adjustment rate method. And GDP deflator method cannot reflect real price because of applying fixed index in whole construction cost for calculating fluctuation rate. Especially, the notification day - the base point influences fluctuation rate and fluctuation amount strongly in GDP deflator method.
A Study on Normal Range of Surface Deflection for Epoxy Asphalt Pavement using Light Weight Deflectormeter
Park, Ki Sun ; Kim, Kyung Nam ; Kim, Nak Seok ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 229~236
DOI : 10.12652/Ksce.2015.35.1.0229
In this study, the resilient modulus test and Light Weight Deflectormeter (LWD) test were conducted to simulate the moving vehicle load for the evaluation of the internal failure of epoxy asphalt pavement. The Measured displacement in the resilient modulus test of epoxy asphalt concrete showed very little residual deformation under repeated loads unlike the conventional asphalt. Therefore, the test results were evaluated as a normal state due to its similarity with elastic deformation. The deflection results from the resilient modulus tests were converted to the surface deflection modulus and the normal range of surface deflection modulus was estimated applying LWD measurement of 1 SIGMA level. Internal failure of pavements were estimated using the suspicious failure range at
and hysteresis. Internal moisture penetration and a decrease in bonding were observed in partial areas at
of surface deflection. However, the areas showed inflection points in the hysteresis. Field investigation by suggested criterion indicated a high degree of accuracy.
A Study on Development of CPTED Evaluation Indicators and Assessment of Types in Neighboring Park - Focused on Neighborhood Parks in Busan -
Sohn, Jee Hyun ; Kim, Jong Gu ; Kim, Yu Jun ;
Journal of The Korean Society of Civil Engineers, volume 35, issue 1, 2015, Pages 237~254
DOI : 10.12652/Ksce.2015.35.1.0237
Neighborhood Parks are important facilities for urban residents, which provide recreation and vitality to users. But it can degenerate into crime-ridden area in the absence of control system. Recently, Crime Prevention Through Environmental Design is confirmed to be effective for safety enhancement, Ministry of Land, Infrastructure and Transport promulgates enforcement regulation about urban parks and greens. In the enforcement regulation, consideration of CPTED in park design is mandatory. However, there is no systematic guideline for the application and continuous maintenance control. So we develop evaluation indicators of neighborhood park about CPTED, and verify the weighted value of the evaluation indicator through survey targeting related field experts. Then, we evaluate safety of neighborhood parks in Busan using developed evaluation indicators, by three types of CPTED application level. On the physical design elements Busan Citizen Park which applied CPTED method from the design phase received the remarkably hightest score, whereas, on the social elements score was investigated differently in accordance with characteristics of each park.