• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1723-1726
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• 2003

Clean and well maintained roadway signs are important for preserving driver's safety. The existing signs on the roadway must be periodically re-painted in order to maintain clean state. However, current sign painting operations are manually performed now. These are very slow and workers are exposed to very dangerous and hazard working environment. In this paper, we present the method for automating this job with gantry robot and spray system. In addition, we suggest two design concepts to resolve the problem that it is impractical to make the gantry system so big as to cover whole lane width. In order to show the validity of this system, the painting operation is simulated and experimentally executed.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.09a
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• pp.295-301
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• 2001

For the seismic analysis of typical roadway bridges provisions are given in most codes for analysis models, which describes however only fundamental modelling methods according to the basic theories of structural dynamics. In practice even conventional non-seismic analysis models, separate super- and substructure models, are applied, which are not adequate because of neglecting connection elements. In this study three typical roadway bridges, a Steel box bridge, a PC beam bridge and a PC box bridge are selected and simple models integrating super- and substructure as well as connection elements are given. The simple models are composed with frame elements with lumped masses representing stiffness and mass characteristics of the selected bridges. To check the properness of the simple models, analysis results with the simple models are compared with those obtained with detailed models in view of bridge failure mechanisms. It is proved that the simple models can be used in the preliminary design phase fur the determination of failure mechanisms of typical roadway bridges.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1518-1523
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• 2003

Automation of roadway sign painting offers more safety for workers, shortening of work period, etc., compared with manual painting. In this study, an automated system using a gantry-type robot was developed for roadway sign painting which has been done manually. Any characters (Korean and English) as well as symbols can be painted by the system. A simulator was also developed, which can show the painted results in advance. The developed system performed well, and the signs painted by the system were found to be as accurate as those made by the simulator.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.17-23
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• 2008

In this paper, we used "Double Photometric System for Road Lighting" and measured roadway lighting of the metropolitan area by a measurement of illuminance and luminance. As a result, so many roads were dissatisfied with the permitted range of roadway lighting because of the road shape, lighting method, trees lining a street and obstacles.

• International Journal of Ocean System Engineering
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• v.2 no.2
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• pp.92-96
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• 2012

This study presents a rockfall impact analysis of a typical roadway. Dynamic finite element analyses using ANSYS AUTODYN are conducted to determine the effect of the drop heights (5 m, 10 m) on the damage to a roadway model. The Rockfall is modeled as a spherical shape with a weight of 400 kg, and each drop height is converted to a corresponding impact velocity to save computational time. The roadway model is comprised of an asphalt layer, base layer, sub-base layer, and sub-grade layer. In this paper, the asphalt is modeled using a linear elastic model. The base layer, sub-base layer, and sub-grade layer are modeled using a Mohr-Coulomb model. From the analyses, the effects of the drop height on the damages and stresses are examined and discussed.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.376-380
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• 2015

Life-Cycle Cost Analysis (LCCA) for highway projects is known as an effective analytical technique that uses economic principles to evaluate long-term alternative investment options, especially for comparing the values of alternative pavement design structures and construction strategies. In the Unites States, the 2012 Moving Ahead for Progress in the 21^st Century Act (MAP-21) amended the United States Code to mandate that the United States Government Accountability Office (GOA) conducts a study of the best practices for calculating life-cycle costs and benefits for the federally funded highway projects in 2013. The RealCost 2.5CA program was developed and adapted as an official LCCA tool to comply with regulatory requirements for California state highway projects in 2013. Utilization of this California-customized LCCA software helps Caltrans to achieve substantial economic benefits (agency cost and road user cost savings) for highway projects. Proper implementation of LCCA for roadway construction and rehabilitation would deliver noticeable savings of agency's roadway maintenance cost especially in developing counties where financial difficulties exist.

• Journal of Korean Society of Transportation
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• v.19 no.6
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• pp.255-256
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• 2001

• Tunnel and Underground Space
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• v.24 no.3
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• pp.212-223
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• 2014

In this study, the stability analyses for metal mine roadways at a great depth were performed. In-situ stress measurements using hydrofracturing, numerous laboratory tests for rock cores and GSI & RMR classifications were conducted in order to find the physical properties of both intact rock and in-situ rock mass distributed in the studied metal mine. Through the scenario analysis and probabilistic assessment on the results of rock mass classification, the in-situ ground conditions of mine roadways were divided into the best, the average and the worst cases, respectively. The roadway stabilities corresponding to the respective conditions were assessed by way of the elasto-plastic analysis. In addition, the appropriate roadway shapes and the support patterns were examined through the numerical analyses considering the blast damaged zone around roadway. It was finally shown to be necessary to reduce the radius of roadway roof curvature and/or to install the crown reinforcement in order to enhance the stability of studied mine roadways.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.6
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• pp.162-172
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• 2009

Improvement of roadway environments to accommodate elderly drivers' declining driving capabilities are required. Currently, even the types of roadway designs vulnerable to elderly drivers have not been revealed in Korea. Thus, this study aims to analyze the types and vulnerabilities of the roadway designs that elderly drivers experience more accidents based on crash data of the Korean National Police Agency. This study has also reviewed foreign guidelines enhancing their safety on different roadway designs. Compared with normal drivers, elderly drivers tend to be more frequently involved in traffic accidents on intersections and vehicle-to-vehicle accidents on curved roadway segments. Assuming freeway interchanges are also risky sections, this study has also examined several methods to reduce elderly driver-related accidents on freeway ramp areas.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.567-582
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• 2022

In the present study, a series of physical experiments and numerical simulations were conducted to investigate the effects of mode I and mixed-mode I/II cracks on the fracture modes and stability of roadway tunnel models. The experiments and simulations incorporated different inclination angle flaws under both static and dynamic loads. The quasi-static and dynamic testing were conducted by using an electro-hydraulic servo control device and drop weight impact system (DWIS), and the failure process was simulated by using rock failure process analysis (RFPA) and AUTODYN software. The stress intensity factor was also calculated to evaluate the stability of the flawed roadway tunnel models by using ABAQUS software. According to comparisons between the test and numerical results, it is observed that for flawed roadways with a single radical crack and inclination angle of 45°, the static and dynamic stability are the lowest relative to other angles of fractured rock masses. For mixed-mode I/II cracks in flawed roadway tunnel models under dynamic loading, a wing crack is produced and the pre-existing cracks increase the stress concentration factor in the right part of the specimen, but this factor will not be larger than the maximum principal stress region in the roadway tunnel models. Additionally, damage to the sidewalls will be involved in the flawed roadway tunnel models under static loads.