• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.589-594
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• 2010

Superimposition of horizontal and vertical curves may hamper the ride comfort and running stability of train and largely affect the maintenance costs. However, in many cases, it is not easy to make a track alignment plan because of the geographic conditions or undesirable environmental factors. In this paper, a comparative study on the effect of superimposition of vertical and horizontal curve on the ride comfort and optimum horizontal curve conditions was performed. That is, optimal cant and ride comfort analysis with and without a vertical curve superimposed on the horizontal curve were evaluated. Also the superimposition effect on ride comfort and alignment conditions in high speed zone were evaluated. From the analysis results, it was found that the ride comfort is similar to that at the only horizontal curves when applying the compensation cant for the superimposed site.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.309-314
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• 2003

A vertical curve should be installed in straight section. In case, it be installed on horizontal curved section, safety factor go down. In this study, it is calculated that the deficiency of cant about vertical curve radius on horizontal curved section. The result of this study will be used on planning the tack layout of railroad and design the track construction.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1943-1950
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• 2010

Superimposition of horizontal and vertical curves may hamper the ride comfort and the running stability of train and largely affect the maintenance cost. However, in many cases, it's not easy to make a track plan because of the fixed points (bridge, tunnel, turnout, catenary system, etc.) to be avoided due to the geographic conditions or to be passed for utilization of existing structures. In this study, when the horizontal and vertical curves are superimposed, in order to optimize the horizontal curve in aspect of the ride comfort, the object function $P_{CT}$ was developed and verified by vehicle dynamic analysis. Also, the solution algorithm for simplified evaluation method was presented.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.33-46
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• 2008

A two-lane highway has a high rate of head-on collisions, sideswipe collisions, crashes with an fixed object. This study was to analyze the weakness of a cross section and a horizontal curve in a two-lane highway and find countermeasures to improve the traffic operations and safety. This study evaluated the effectiveness of widening, curve flattening and superelevation, verified it with a case study and assessed the economical efficiency. This study selected the difference between tangent section operating speeds and curve section operating speeds as an evaluation index of horizontal curve section in a two-lane highway. The results indicated that curve flattening is the best way to improve the traffic safety in a two-lane highway. This study has implication that it provides the quantitative effects of curve flattening. Also directions for future study were discussed.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.3
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• pp.77-84
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• 2016

In 2012, total GHG emissions in transport sector reached 88 Million ton CO2eq. The emissions generated in the road accounted for 94% of the transport sector. Currently, there are many efforts to operate an education and campaign for eco-driving. However study for eco-friendly vehicle control considering road alignment is limited. Therefore, the purpose of this study is to address fuel-efficient driving strategy in horizontal curve section. To fulfill the goal, designed ideal freeway horizontal curve road follows regulations about road structure. And safety speed is calculated for considering vehicle's safety on horizontal curve road. Authors composed the acceleration and deceleration scenario for each horizontal curve section and generated the speed profiles that are limited by the safety speed. Speed profiles are converted into force that horizontal curve affect to fuel consumption. Then, we calculated fuel consumption using Comprehensive Modal Emission Model. Then, we developed eco-driving strategy by selecting most fuel-efficient scenario. To validate this strategy, we selected study site and compared fuel consumption for eco and manual driving. As the result, fuel consumption when driver used eco-driving was lessened by 20.73% than that of manual driving.

• International Journal of Highway Engineering
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• v.14 no.1
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• pp.95-102
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• 2012

This study has been conducted to characterize the relations between the accident rate and the overlap section elements where the horizontal alignment and vertical alignment are overlapped. The researches were performed on Horizontal curve sections of 4-lane highways with 100km/h of design speed and speed limit. Korea Highway Corporation's Geographic Figurative Information System was adopted for geometric organization and Highway Traffic Accident Statistics was used. The results reveal that sections made of a single slope without vertical curve has greater accident rate than those with vertical curve, and that sections with 1 vertical curve are higher in the accident rate than those with over 2 vertical curve. For the sections with 1 vertical curve, SAG sections are higher than CREST sections and for the previous straight section of horizontal curve are higher than curved ones. In particular, when the road surface is wet, the accident rate is closely related with SAG vertical curves or leftward horizontal curved sections. This study will have meanings that it proposes the importance of design of road alignment by taking consideration of 3D synthetic alignment conditions for improvement of the road safety.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.575-582
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• 2000

The flat Dilatometer test(flat DMT) has been known as an in-situ testing method which is simple and robust to use, and reliable for site stratification and evaluation of soil properties. It was designed and proposed by Marchetti in 1975 to characterize the properties of soils. There are many researches that have been done to evaluate the horizontal coefficient of consolidation from the dissipation test results of flat DMT on normally consolidated and slightly overconsolidated clays. The representative estimation methods of estimating the horizontal consolidation coefficient are DMT-C method which uses a C-reading dissipation curve and DMT-A method which uses a A-reading dissipation curve. This paper represents a comparison analysis of those two methods in obtaining the horizontal coefficients of consolidation. The reference values are also obtained by CPTU and other laboratory tests. The applicability of using flat DMT to characterize the consolidation behavior is also reviewed for two sites. According to the results, DMT-A method is not suitable for silty clays possibly because of the compressibility characteristics. As for the normally consolidated and slightly overconsolidated clays, the results obtained from the two methods are comparable with each other as well as with the laboratory test results.

• Structural Monitoring and Maintenance
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• v.5 no.1
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• pp.111-127
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• 2018

Horizontal displacement of high-rise building is an essential index for assessing the structural performance and safety. In this paper, a novel inclinometer-based method is proposed to address this issue and an algorithm based on three spline interpolation principle is presented to estimate the horizontal displacement of high-rise buildings. In this method, the whole structure is divided into different elements by different measured points. The story drift angle curve of each element is modeled as a three spline curve. The horizontal displacement can be estimated after integration of the story drift angle curve. A numerical example is designed to verify the proposed method and the result shows this method can effectively estimate the horizontal displacement with high accuracy. After that, this method is applied to a practical slender structure - Shanghai Tower. Nature frequencies identification and deformation monitoring are conducted from the signal of inclinometers. It is concluded that inclinometer-based technology can not only be used for spectrum analysis and modal identification, but also for monitoring deformation of the whole structure. This inclinometer-based technology provides a novel method for future structural health monitoring.

• Steel and Composite Structures
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• v.32 no.6
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• pp.717-729
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• 2019

A horizontal cyclic test was carried out to study the seismic performance of lightweight aggregate concrete filled steel tube (LACFST). The constitutive and hysteretic model of core lightweight aggregate concrete (LAC) was proposed for finite element simulation. The stress and strain changes of the steel tube and concrete filled inside were measured in the experiment, and the failure mode, hysteresis curve, skeleton curve, and strain curve of the test specimens were obtained. The influence of axial compression ratio, diameter-thickness ratio and material strength were analysed based on finite element model. The results show that the hysteresis curve of LACFST indicated favourable ductility, energy dissipation, and seismic performance. The LACFST failed when the concrete in the bottom first crushed and the steel tube then bulged, thus axial force imposed by prestressing was proved to be feasible. The proposed constitutive model and hysteretic model of LAC under the constraint of its steel tube was reliable. The bearing capacity and ductility of the specimen increase significantly with increasing thickness of the steel tube. The bearing capacity of the member improves while the ductility and energy dissipation performance slightly decreased with the increasing strength of the steel and concrete.

• Journal of Korean Society of Transportation
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• v.22 no.7 s.78
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• pp.139-146
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• 2004

Road design should be conformed to the expectancy of drivers. The alignment such as long tangent followed by the sharp horizontal curve should be avoided for the road design consistency. Currently, operating speed profile model is generally used to check the consistency of the successive road alignments. In this model, the hypothesis about the drivers' behaviour on the long tangent followed by the sharp horizontal curve is also included. This study compares the hypothesized drivers' behaviour in the existing operating speed profile model with the actual drivers' behaviour observed at the two lane rural roads. In addition to this, comparison between the acceleration for the vehicles approaching and departing horizontal curves suggested by the foreign research and the value observed at this study was made, From this study, it was concluded that the hypothesis in the existing model was well representing the actual drivers' behaviour. The deceleration for vehicles approaching the horizontal curves was ranged $0.39{\sim}1.06m/s^2$ with the average of $0.66m/s^2$. The average acceleration for the vehicles departing horizontal curves was $0.22m/s^2$.