• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.2
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• pp.293-307
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• 1998

This study has been divided into two parts, 1) literature review and 2) a case study. Based on literature review and case studies found in Korea and abroad, this study aimed at classifying wildlife passages and establishing their development procedures in order to establish a theoretical ground for the development of wildlife passage as a way to link habitats that have been fragmented by the construction of roads and other developments. The results of the literature review are as follows : 1) Impact of road construction on surrounding ecological environment is found in various aspects. Along with damage of habitats as direct impact, decrease of biodiversity and simplification of species due to limited breeding and movement are cited as possible indirect impact. 2) In order to lessen the impact generated from fragmented habitats, various types of wildlife passage are being developed in Europe and are showing positive results. 3) In Korea, interests on animal passages have been rising recently. The ministry of Environment and local authorities are establishing development plans for the passages. However, practical materials on the usefulness of adoped methods are not available.4) In order to create an effective wildlife passage, decisions have to be made first on basic factors of planning and designing such as ecosystem rehabilitation methods and surveys on wildlife movement routes and habitat environment. Based on this, in a planning and designing stage, the location and type of a passage, size and measures to attract animals and prevent a collision need to be finalized. This should be followed by a series of process of maintenance, management and monitoring after the development. Based on the results of a theoretical study to develop an wildlife passage, Part 2 of this study deals with the results of an experiment through a specific planning and design that includes a process of ecological surveys, site selection, type selection, ecosystem infrastructure, planting design and construction details on an actual study area and presents them as a model project.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5184-5191
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• 2013

The automated quantity take off technique using BIM authoring tools has been recently issued, and the studies of this method for the accuracy, efficiency, and the unit computing for the simple volume, area and number have been developed. Meanwhile the main concerns such as the details for the level of modelling, and the costs and time for the calculating BOQ item are still required to study. In this paper, the earth works, drainage works, pavement works, and facility works using BIM authoring tools are designed in 3D, and the applicability of automated quantity take off technique using BIM authoring tools is discussed, respectively. As a result, automated quantity take off are limited in the earth works, drainage works, pavement works, and facility works. But Most items of BOQ can be supported in Re-bar model.

• International Journal of Highway Engineering
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• v.17 no.2
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• pp.89-98
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• 2015

PURPOSES : The objective of this study is to evaluate the performance properties of chip seals and fog seals with polymer-modified emulsions. METHODS : The performance of chip seals and fog seals was evaluated on the basis of common issues in surface treatments. Granite aggregate and four types of asphalt emulsions (one of the unmodified and three of the modified emulsions) were used considering the usage in field. A Vialit test was performed to determine the aggregate retention, and the MMLS3 (Third Scale Model Mobile Load Simulator) test was conducted to determine the aggregate retention, bleeding, and rutting. In addition, the fog seal specimens were tested by the BPT (British Pendulum Test) to evaluate skid resistance. RESULTS AND CONCLUSIONS : Overall, the polymer-modified emulsions (PMEs) showed better aggregate retention and bleeding resistance for both chip seals and fog seals. When comparing the performance of the PMEs, the difference was not considerable. In addition, PMEs present significantly better rutting resistance than unmodified emulsions. For skid resistance, if the recommended mix design is applied, the specimens do not cause issues with skid resistance. Although all of the fog seal specimens were over the criteria for skid resistance, the specimen fabricated by the high emulsion application rate (EAR) of the unmodified emulsion was nearly equivalent to the skid value criteria. Therefore, the use of an unmodified emulsion with a high EAR should be carefully applied in the field.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.239-249
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• 2011

The behavior of the fiber reinforced concrete (FRC) base under environmental loads was analyzed numerically as a fundamental study to develop a high structural and functional performance composite pavement system in which the base was formed using FRC and the asphalt or cement concrete surface was placed on it. A two-dimensional finite element model of the FRC base was developed and the sensitivity study was performed with the variables including slab thickness of base, thermal expansion coefficient, elastic modulus, and tensile and compressive strengths. The crack spacing and crack width were selected as representatives of the base behavior. The effects of the selected variables on the crack spacing and crack width were analyzed and the sensitive variables were determined. The results of this study could be useful to determine the optimal material properties of the FRC base for combining well with the surface materials.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.1-11
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• 2007

The rapid growths of economy and automobiles since the 1970's have caused serious traffic jams and environmental disruption in urban areas. To relieve these problems caused by urbanization, there should be considered alternative means of transportation modes. Many developed countries have accepted bicycles as a so called "Green Mode" for environmentally oriented strategies to increase the qualities of urban lives. Korea have also attempted various means to raise bicycle usages. In this research, significant factors affecting bicycle crashes at signalized intersections in urban areas were studied. The model results showed that Poisson regression is the best fit methodology for data modeling and revealed that traffic volume, a number of driveways, configuration of the ground, presence of bicycle path, school, and bus stop, residential area, size of intersection are significant factors affecting the bicycle crashes.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.27-37
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• 2007

This research was conducted to determine the optimum lifting positions on precast concrete slabs for precast concrete pavement construction, based on the analysis of concrete stress distribution under various lifting conditions. To analyze stresses in concrete slabs, the finite element method was implemented and a numerical model of the precast slab that was going to be used in the experimental construction was developed. Changes in the stress distribution due to the lifting angle were investigated because slab lifting is not always performed in the perpendicular direction to the slab surface. In addition, the effect of the lifting level, the distance between the neutral axis of the slab and the lifting point, on the stress distribution was investigated since the lifting point is not always at the neutral axis of the slab. To consider the actual steel design of the precast slab, the effect of the reinforcement near the lifting point was also investigated. From this study, the optimum lifting positions of the precast slabs were determined according to the lifting angle and level, and the results were compared with the lifting positions used in the PCI standards.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.39-49
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• 2007

The objective of this study was to investigate features of transverse crack occurrence and propagation in continuously reinforced concrete pavement(CRCP) when subjected to environmental loading. The finite element model of CRCP was developed and the element removal method was implemented to predict the crack propagation process. To investigate the effect of the type of environmental loading on the CRCP behavior and cracking aspects, the following three different cases were considered: (1) the temperature gradient between top and bottom of the slab does not vary and the constant temperature drop throughout the depth occurs; (2) the temperature at the slab bottom does not vary and the temperature gradient increases; and (3) the temperature between the mid-depth and the bottom of the slab is the same and does not vary and the temperature at the top decreases. The analysis results showed that the crack occurrence and propagation through the depth of the slab in CRCP were significantly affected by the type of environmental loading. The changes in stress distribution and displacements during the crack occurrence and propagation process could also be investigated.

• International Journal of Highway Engineering
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• v.16 no.3
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• pp.35-41
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• 2014

PURPOSES : The dynamic modulus for a specimen can be determined by using either the non-destructed or destructed testing method. The Impact Resonance Testing (IRT) is the one of the non-destructed testing methods. The MTS has proved the source credibility and has the disadvantages which indicate the expensive equipment to operate and need a lot of manpower to manufacture the specimens because of the low repeatability with an experiment. To overcome these shortcomings from MTS, the objective of this paper is to compare the dynamic modulus obtained from IRT with MTS result and prove the source credibility. METHODS : The dynamic modulus obtained from IRT could be determined by using the Resonance Frequency (RF) from the Frequency Response Function (FRF) that derived from the Fourier Transform based on the Frequency Analysis of the Digital Signal Processing (DSP)(S. O. Oyadigi; 1985). The RF values are verified from the Coherence Function (CF). To estimate the error, the Root Mean Squared Error (RMSE) method could be used. RESULTS : The dynamic modulus data obtained from IRT have the maximum error of 8%, and RMSE of 2,000MPa compared to the dynamic modulus measured by the Dynamic Modulus Testing (DMT) of MTS testing machine. CONCLUSIONS : The IRT testing method needs the prediction model of the dynamic modulus for a Linear Visco-Elastic (LVE) specimen to improve the suitability.

• International Journal of Highway Engineering
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• v.20 no.2
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• pp.57-65
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• 2018

PURPOSES : The study aims to predict the service life of national highway asphalt pavements through deep learning methods by using maintenance history data of the National Highway Pavement Management System. METHODS : For the configuration of a deep learning network, this study used Tensorflow 1.5, an open source program which has excellent usability among deep learning frameworks. For the analysis, nine variables of cumulative annual average daily traffic, cumulative equivalent single axle loads, maintenance layer, surface, base, subbase, anti-frost layer, structural number of pavement, and region were selected as input data, while service life was chosen to construct the input layer and output layers as output data. Additionally, for scenario analysis, in this study, a model was formed with four different numbers of 1, 2, 4, and 8 hidden layers and a simulation analysis was performed according to the applicability of the over fitting resolution algorithm. RESULTS : The results of the analysis have shown that regardless of the number of hidden layers, when an over fitting resolution algorithm, such as dropout, is applied, the prediction capability is improved as the coefficient of determination ($R^2$) of the test data increases. Furthermore, the result of the sensitivity analysis of the applicability of region variables demonstrates that estimating service life requires sufficient consideration of regional characteristics as $R^2$ had a maximum of between 0.73 and 0.84, when regional variables where taken into consideration. CONCLUSIONS : As a result, this study proposes that it is possible to precisely predict the service life of national highway pavement sections with the consideration of traffic, pavement thickness, and regional factors and concludes that the use of the prediction of service life is fundamental data in decision making within pavement management systems.

• Journal of Convergence for Information Technology
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• v.10 no.10
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• pp.128-134
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• 2020

Recently, the damages by typhoons and heavy rains are increasing due to the climate change. However, we are still vulnerable to inundation disaster due to various causes such as poor physical flood control and lacks of disaster and safety management. Therefore, it is necessary to establish systems to ensure safety and prepare practical countermeasures that can minimize damage when an inundation occurs, thereby minimizing economic loss and casualty. In this study, hydrodynamic inundation modelings were implemented to analyze the "Noryangjin reservoir inundation accident" and "Choryang No. 1 underground road inundation accident." and spatial risk was assessed by a quantitative hazard index. In addition, cause and effect diagrams were provided to present the risk causes in terms of physical and managemental aspects.