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Kim H.-J.,Korea Expressway Corporation Research Institute | Sim J.,Hanyang University
KSCE Journal of Civil Engineering | Year: 2015

In this paper, a more effective construction method is introduced, wherein the mechanical advantages of Glass Fiber Reinforced Polymer (GFRP) are applied to the slip-form method. The slip-form method, which is a typical moving form method, has advantages such as reduced construction duration and simple components because it enables continuous forming work of concrete in a single construction. However, it is vulnerable to corrosion, quality control is difficult, and the form plate cannot be reused. In this study, a tensile test was carried out on a GFRP plate by using a new method to apply the steel form to the GFRP plate. Effective GFRP slip-form shape and the application method were proposed by conducting finite element analysis and parametric analysis based on the results of the GFRP plate tensile test; performance was verified through a structural test. From the test results, the GFRP slip-form showed better structural performance than the steel form, and the GFRP slip-form construction method may reduce costs because of its reusability, easy quality control, and reduced construction duration. © 2015 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg Source


Kim H.-J.,Korea Expressway Corporation Research Institute | Kim Y.,Cooperation Technology | Sim J.,Hanyang University
KSCE Journal of Civil Engineering | Year: 2015

This study was conducted to assess the field applicability of the Glass Fiber Reinforced Polymer (GFRP) slip-form proposed in previous studies by testing its performance-related properties in various experiments. We compared the initial curing temperature of concrete, which exerts the greatest impact on reducing the construction duration in the slip-form system, with that when using a steel slip-form. We measured the friction force to compare the cross section formability of the two methods. We then conducted a mock-up test on the basis of the experimental results and assessed its usability and field applicability. The GFRP form maintained a higher curing temperature than the steel form, and the difference in the curing temperature was larger with an increase in the air temperature and smaller with a decrease in the air temperature. The slip-up rate in the slip-forming was confirmed to be affected the most by the initial curing temperature of the concrete, whereas the cross-section formability was affected by the friction force and adhesion of the concrete. The results of the experiments verified that the GFRP slip-form efficiently overcomes the drawback of the steel slip-form system and maximizes the advantages of slip-forming. © 2015 Korean Society of Civil Engineers and Springer-Verlag Berlin Heidelberg Source


Lin W.,Chung - Ang University | Ryu S.,Korea Expressway Corporation Research Institute | Cho Y.-H.,Chung - Ang University
Journal of Performance of Constructed Facilities | Year: 2016

As industrialization advances, the increase in impermeable areas in urban regions has changed the water circulation system. Hence, many environmental issues such as heat islands and city floods have arisen. To solve this issue, related research with a high budget allocation is currently being carried out. A method of addressing this issue is to utilize permeable block pavements. The bearing capacity and hydrological efficiency of permeable block pavement with different base types was evaluated in this study using two accelerated pavement testings (APTs). Rutting was evaluated by performing a comparative analysis in each permeable block pavement. Furthermore, the hydrological characteristics were reviewed through a rainfall simulation experiment. The results of APT show that performance of permeable block pavements varies depending on the base type and traffic volume. Based on the result, it was demonstrated that the permeable block pavement is applicable for a vehicle road as well as the sidewalk. In addition, it was demonstrated that this pavement can improve the water circulation system. © 2014 American Society of Civil Engineers. Source


Kim D.H.,Kunsan National University | Lee S.G.,Kunsan National University | Lee I.K.,Korea Expressway Corporation Research Institute
Renewable Energy | Year: 2014

Considering nonlinear soil-pile interaction, seismic fragility analysis of offshore wind turbine was performed. Interface between ground soils and piles were modeled as nonlinear spring elements. Ground excitation time histories were applied to spring boundaries. Two methods of applying ground motion were compared. Different time histories from free field analysis were applied to each boundary in the first loading plan (A). They were compared with the second loading plan (B) in which the same ground motion is applied to all boundaries. Critical displacement for wind turbine was proposed by using push-over analysis. Both the stress based and the displacement based fragility curves were obtained using dynamic responses for different peak ground accelerations (PGAs). In numerical example, it was shown that seismic responses from loading plan A are bigger than from plan B. It seems that the bigger ground motion at surface can cause less response at wind turbine due to phase difference between ground motions at various soil layers. Finally, it can be concluded that layer by layer ground motions from free field analysis should be used in seismic design of offshore wind turbine. © 2013 Elsevier Ltd. Source


Lin W.,Shanghai Maritime University | Park D.-G.,Pavement Research Center | Ryu S.W.,Korea Expressway Corporation Research Institute | Lee B.-T.,Chung - Ang University | Cho Y.-H.,Chung - Ang University
Construction and Building Materials | Year: 2016

Pervious pavement has been used widely due to efficient hydrological characteristics such as reduction of runoff during floods, providing delay of rainwater into sewer systems and ground water quality improvement. However, clogging prevents it from functioning properly due to sedimentation after a short period of service, which results to poor permeability and performance of pervious pavement. In this study, the causes of clogging were investigated and a clogging simulator was developed in order to evaluate the sustainable permeability of porous concrete block pavement in advance. Furthermore, a test method for verifying the sustainability of infiltration which can predict and assess the permeability performance by years of service was proposed. In addition, the penetration of contaminants also varies depending on vehicle vibration and the rainwater that permeates together with it. It was found that the pores were easily clogged with the vibration frequency increased, but with the amount of contaminants increased to a degree clogging had less influence on vibration. When various types of porous concrete block pavers were evaluated with the proposed sustainable permeability test method, the coefficient of permeability before and after the test have shown very high correlation. © 2016 Published by Elsevier Ltd. Source

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