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Seoul, South Korea

Ahn J.-H.,Yonsei University | Yoon J.-H.,Yonsei University | Kim J.-H.,Yooshin Engineering Corporation | Kim S.-H.,Yonsei University
Journal of Constructional Steel Research | Year: 2011

Integral abutment bridges can reduce the amount and cost of construction and maintenance work since they do not have expansion joints and shoes in order to increase stability and durability of the bridges' system. Integral abutment bridges normally have single-row H-pile systems to resist the behaviors under service loading conditions such as thermal loading. In order to transfer member forces between abutments and H-pile, the abutmentpile connection in the integral abutment bridge should have rigid behavior. Therefore, the installation of reinforcing bars and minimum installed length of the piles in the concrete abutment are required to resist bearing force and deformation caused by shear forces and bending moments. This study examines the abutmentpile connections in the integral abutment bridge to improve the shear and bearing resistance of concrete abutment and constructability of abutmentpile connections for the single-row H-pile system with weak axis. Three types of new abutmentpile connections are proposed in this study. They feature transverse reinforcing bars perforated in H-pile, stud connectors, and perfobond rib connectors on the flange of H-pile, respectively. They are intended to increase the stiffness and strength so that they will better resist the bearing force caused by deformations and rotations at abutment H-pile concrete. Loading tests and FE analysis were conducted to evaluate the stiffness and behaviors of proposed connections for half scale abutmentH-pile connection specimens. From the test results, proposed abutmentH-pile connections were evaluated to secure sufficient stiffness, rotational stiffness, and bearing strength. © 2011 Elsevier Ltd. All rights reserved. Source

Park S.,Yooshin Engineering Corporation | Roberts L.A.,South Dakota School of Mines and Technology | Misra A.,University of Kansas
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2012

With the increasing use of augered cast-in-place and drilled displacement piles in new construction, it is important that proper design parameters be incorporated when evaluating pile performance using reliability-based design methods. Although augered piles can be distinguished from bored piles, including drilled shafts, and driven piles by the magnitude of the effective stress changes they produce in the vicinity of the pile during construction, the current design methods for augered piles generally use the same design methods as those used for bored or driven piles. To enhance the efficiency of the augered piles, a unique design method must be developed. This paper focuses on developing a design methodology for axially loaded augered piles installed in predominately sandy soils using the t-z method. To develop the design parameters for augered piles, back-calculation of the t-z parameters was conducted using static loadetest data. The data from 17 static pile load tests conducted on augered piles from construction sites were obtained. Load-settlement and load-transfer curve fittings were performed using the t-z model to back-calculate a set of soil-pile interfacial and tip parameters, along with their variability. Correlations of the back-calculated t-z model parameters with the standard field investigation data were conducted, and the most-promising correlations were incorporated into the t-z modelebased design methodology. Subsequently, the t-z method for augered pile design was evaluated by comparing the predicted and measured load-settlement and load-transfer curves. In addition, the t-z method was used to perform probabilistic load-settlement analyses and obtain resistance factors applicable to the load and resistance factor design approach. © 2012 American Society of Civil Engineers. Source

Oh H.-J.,Korea Institute of Geoscience and Mineral Resources | Kim Y.-S.,Kyungpook National University | Kim Y.-S.,Yooshin Engineering Corporation | Choi J.-K.,Korea Ocean Research and Development Institute | And 2 more authors.
Journal of Hydrology | Year: 2011

This study analyzed the relationships between groundwater specific capacity (SPC) and its related hydrological factors to assess the sensitivity of each factor and map the regional groundwater potential for the area of Pohang City, Korea, using a geographic information system (GIS) and a probability model. All related factors including topography, geology, lineament, and soil data were collected and entered into a spatial database. SPC data were collected from well locations, and SPC values of ≥6.25m3/d/m, corresponding to a yield of 500m3/d, were input to a spatial database. SPC data were then randomly selected in a 66/34 ratio to train and validate the model. A frequency-ratio model and sensitivity analysis were used to determine the relationships between SPC and its related factors and the importance of SPC-related factors. Sensitivity analysis allows for comparison of the combined effects of all factors except for one. The validation of the groundwater potential map overlain by all factors showed 77.78% accuracy. In the sensitivity analysis, the best accuracy was obtained by omitting ground elevation data (78.64%), and the worst accuracy resulted when soil texture was not included (76.64%). The results show that soil texture had the greatest effect on the groundwater potential and ground elevation had the least effect. Such information and the maps generated from it can be applied to groundwater management and groundwater resource exploration. © 2010 Elsevier B.V. Source

Joo K.-S.,Hyundai Engineering | Suh Y.-H.,Hyundai Engineering | Park K.-H.,Hyundai Engineering | Huh D.-H.,Yooshin Engineering Corporation | And 2 more authors.
Harmonising Rock Engineering and the Environment - Proceedings of the 12th ISRM International Congress on Rock Mechanics | Year: 2012

The subsea tunnel with a length of 6.927 km between Boryung and Taean will be the first mined road tunnel in Korea. This tunnel, two-lane two tubes, has been planned to pass approximately maximum 60m under seabed and 80m under sea level. It is a drained tunnel under control of water ingress by grouting for watertight and is excavated by blasting. Project status is on the end of the detail design stage and construction will be started in the end of 2010. This paper intends to introduce some considerations about the secondary lining design considering the water inflow in the mined subsea tunnel. Firstly it is introduced the design concept of the secondary lining considering the water inflow and the drained material characteristic. And, the combination of the rock loads and residual water pressure is studied and proposed. © 2012 Taylor & Francis Group, London. Source

Lee M.-J.,Yooshin Engineering Corporation | Hwang G.,Yooshin Engineering Corporation | Lim J.,Yooshin Engineering Corporation | Kwon S.-D.,Chonbuk National University
Long Span Bridges and Roofs - Development, Design and Implementation | Year: 2013

This paper presents the prototype design results of a suspension bridge of which main span reaches up to 2800m. A new design code (draft) developed with supports of the Super Long Span Bridge R&D Center in Korea has been applied to the design. Influences on the design of the main cable, the steel pylon and the orthotropic deck plate are presented. Moreover, the result of optimization on the deck cross-section by wind-tunnel test is summarized. In addition, a preliminary study on a bridge design life has been performed. Important infrastructures such as super long-span bridges may need a longer bridge design life than that of other structure. A bridge with a longer design life essentially requires higher construction cost. A proposal to raise economical efficiency is suggested. Source

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