• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.191-198
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• 2005

Slope failures during heavy rainfall have resulted in death of life and economic loss. In recent years, the research on slope damage assessment using Geographical Information System(GIS) has been actively carried out by researchers of several goverment organizations and schools. The researchers in Highway and Transportation Technology Institute (HTTI) of Korea Highway Corporation has developed the GIS database(DB), including highway, rainfalls, soil or rock geometry, types of damage, etc. and have been working on the damage assessment of highway slopes. The DB has been established and summarized in two different ways, such as highway routes and administrative districts. Grid of rainfall intensity generated by maximum rainfalls of each administrative district has been devloped. It shows good correlation of slope damage with heavy rainfalls. Most of damaged slopes were found in the amount of 100 mm to 300 mm rainfalls.

• International Journal of Highway Engineering
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• v.18 no.3
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• pp.21-32
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• 2016

PURPOSES : In this paper, the analytical solutions suggested to simulate the behavior of rheological fluids were rigorously re-derived and investigated for fixed conditions to evaluate the applicability for the solutions on a mini-cone slump test of cement paste. The selected solutions with proper boundary conditions can be used as reference solutions to evaluate the performance of numerical simulation approaches, such as the discrete element method. METHODS : The slump, height, and spread radius for the given boundary and yield stress conditions that are determined by five different analytical solutions are compared. RESULTS : The analytical solution based on fluid mechanics for pure shear flow shows similar results to that for intermediate flow at low yield stresses. The fluid mechanics-based analytical solution resulted in a very similar trend to the geometry-based analytical solution. However, it showed a higher slump at high yield stress and lower slump at low yield stress ranges than the geometry-based analytical model. The analytical solution based on the mini-cone geometry was not significantly affected by the yield criteria, such as von Mises and Tresca. CONCLUSIONS : Even though differences among the analytical solutions in terms of slump and spread radius existed, the difference can be considered insignificant when the solutions were used as reference to evaluate the appropriateness of numerical approaches, such as the discrete element method.

• Journal of Korean Society of Transportation
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• v.25 no.2 s.95
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• pp.157-165
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• 2007

In this research, a vertical alignment analysis algorithm was developed. The developed algorithm used acquired data from a vehicle with multiple sensors such as a global positioning system (GPS) an inertial navigation system (INS), and a distance measuring unit (DMI) to collect information about vehicle position and altitude. The vertical alignment analysis algorithm includes the identification of vertical tangent sections, the beginning and ending points of vertical curves, and the calculation of length of vortical curves. Also, the algorithm can help build models for vertical tangent sections and vertical curve sections. In order to verify the algorithm, a field survey was conducted at an actual highway section and the result of the field survey was compared to a highway CAD drawing.

• International Journal of Highway Engineering
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• v.16 no.5
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• pp.173-182
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• 2014

PURPOSES : The purpose of the study is to a) explore the operating speed of trucks on rural highways affected by road geometry, and thereby b) develop a predictive model for the operating speed of trucks on rural highways. METHODS : Considering that most of the existing studies have focused on cars, the current study aimed to predict the operating speed of trucks by conducting linear regression analysis on the speed data of trucks operating on the linear-curved-linear portions of the road as a single set. RESULTS : The operating speed in the plane curve portion increased with the length of the curve, and decreased with a lower vertical grade and a smaller curve radius. In the straight plane portion, the operating speed increased with a larger curve radius(upstream), and decreased with an increase in the change of the vertical grade, depending on the length of the vertical curve. CONCLUSIONS : This study developed estimation models of truck for operational speed and evaluated the degree of safety for horizontal and vertical alignments simultaneous. In order to represent whole area of the rural highway, the models should be ew-analyzed with vast data related with road alignment factor in the near future.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.199-206
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• 2005

Engineers have performed slope stability analyses, including Limit Equilibrium Analysis, Finite Difference Analysis and Finite Element Analysis. Each analysis results in different Factor of Safety(FS) for slopes. The comparison of FS results from these stability analyses has been carried out for various conditions, such as geometry of slopes, dry and fully saturated soils, nail and anchor reinforcements. Standard deviations of FS calculated from various slope analyses are 0.03 to 0.04 and 0.22 to 0.48 for the slopes without and with nail or anchor reinforcement, respectively. Construction of tiered concrete retaining wall in addition to nail or anchor reinforcement increases FS of 12% to 29% for fully saturated soils.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.2
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• pp.73-82
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• 1996

A simtered carbide roller mold for reflector which is used for coverof automobile lamp and beacon plate of highway has been developed. The geometry of sintered carbide roller mold has been determined from the analysis of reflector geometry. An acute angle diamond wheel and dressing system also has been designed and developed to manufacture the sintered carbide roller mold.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.170-176
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• 1996

A Sintered carbide roller mold for reflectors which is used for cover of automobile lamp and beacon plate of highway has been developed. The geometry of sintered carbide roller mold has been determined from the analysis of reflector geometry. An acute angle diamond wheel and dressing system also has been designed and developed to manufacture the sintered carbide roller mold.

• Smart Structures and Systems
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• v.19 no.1
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• pp.39-46
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• 2017

Finite element model updating is very effective procedure to determine the uncertainty parameters in structural model and minimize the differences between experimentally and numerically identified dynamic characteristics. This procedure can be practiced with manual and automatic model updating procedures. The manual model updating involves manual changes of geometry and analyses parameters by trial and error, guided by engineering judgement. Besides, the automated updating is performed by constructing a series of loops based on optimization procedures. This paper addresses the ambient vibration based finite element model updating of long span reinforced concrete highway bridges using manual model updating procedure. Birecik Highway Bridge located on the $81^{st}km$ of Şanliurfa-Gaziantep state highway over Firat River in Turkey is selected as a case study. The structural carrier system of the bridge consists of two main parts: Arch and Beam Compartments. In this part of the paper, the arch compartment is investigated. Three dimensional finite element model of the arch compartment of the bridge is constructed using SAP2000 software to determine the dynamic characteristics, numerically. Operational Modal Analysis method is used to extract dynamic characteristics using Enhanced Frequency Domain Decomposition method. Numerically and experimentally identified dynamic characteristics are compared with each other and finite element model of the arch compartment of the bridge is updated manually by changing some uncertain parameters such as section properties, damages, boundary conditions and material properties to reduce the difference between the results. It is demonstrated that the ambient vibration measurements are enough to identify the most significant modes of long span highway bridges. Maximum differences between the natural frequencies are reduced averagely from %49.1 to %0.6 by model updating. Also, a good harmony is found between mode shapes after finite element model updating.

• International Journal of Highway Engineering
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• v.18 no.2
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• pp.103-110
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• 2016

PURPOSES: In this paper, the effectiveness of speed-maintained standardization in road geometry on environmental impact at a downward slope location, based on greenhouse gas (GHG) emission indicators, was studied. Specifically, the aim of this study was to ascertain whether speed-maintained standardization resulted in decreased $CO_2$ emissions as well as noise pollution, due to reduced vehicle speeds. METHODS : In this study, speed-maintained standardization in road geometry was proposed as a means to reduce vehicle speeds, with a view to reducing $CO_2$ emissions and noise pollution. This technique was applied at a downward slope location. The vehicle speeds, $CO_2$ emissions, and noise levels before and after application of speed-maintained standardization were compared. RESULTS: It was found that speed-maintained standardization was effective as a means to reduce speed, as well as $CO_2$ emissions and noise pollution. By applying speed-maintained standardization, it was confirmed that vehicle speeds were reduced consistently. As a result, $CO_2$ emissions and noise levels were decreased by 9% and 11%, respectively. CONCLUSIONS : This study confirmed that speed-maintained standardization in road geometry is effective in reducing vehicle speeds, $CO_2$ emissions, and noise levels. Moreover, there is further scope for the application of this method in the design of roads in urban and rural areas, as well as in the design of highways.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.3
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• pp.230-237
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• 2004

Lane Sensing techniques based on vision sensors are regarded promising because they require little infrastructure on the highway except clear lane markers. However, they require more intelligent processing algorithms in vehicles to generate the previewed roadway from the vision images. In this paper, a lane sensing algorithm using vision sensors is developed to improve the sensing robustness. The parallel stereo-camera is utilized to regenerate the 3-dimensional road geometry. The lane geometry models are derived such that their parameters represent the road curvature, lateral offset and heading angle, respectively. The parameters of the lane geometry models are estimated by the Kalman filter and utilized to reconstruct the lane geometry in the global coordinate. The inverse perspective mapping from the image plane to the global coordinate considers roll and pitch motions of a vehicle so that the mapping error is minimized during acceleration, braking or steering. The proposed sensing system has been built and implemented on a 1/10-scale model car.