Jung Y.-W.,Seoyeong Engineering Co. |
Han S.-I.,Seoyeong Engineering Co. |
Jo D.,Dongseo University
Advances in Intelligent Systems and Computing | Year: 2016
The permeable pavement is one of representative Low Impact Development (LID) facilities which were used to reduce flooding and recover the water cycle in urban environments. Since the unit cost of porous pavement is greater than that of non-porous pavement, the designs of permeable pavement need to consider reduction effect of rainwater runoff and cost of facilities. These are determined by the size and location of facilities. In this study, the optimal design of permeable pavement, considering the size and location of that, was simulated in a developed optimization model using the Harmony Search (HS)algorithm connected to the Storm Water Management Model (SWMM) to calculate urban Rainfall-Runoff. © Springer-Verlag Berlin Heidelberg 2016.
Seong D.,Sungkyunkwan University |
Kim T.,Samsung |
Oh M.,Seoyeong Engineering Co. |
Shin H.,Sungkyunkwan University
Journal of Advanced Concrete Technology | Year: 2011
Despite its importance in the seismic performance of an overall structure, our understanding of the ductility capacity of high-strength concrete (HSC) columns under various loading conditions is relatively limited compared to that of normal- strength concrete (NSC) columns. This study aims to evaluate the seismic performance of HSC columns through a numerical analysis approach. Based on the smeared crack concept, the analysis model consisted of material models for concrete and embedded reinforcement. The brittle behavior and smooth crack surfaces of HSC are some of its main drawbacks in engineering practice. In the proposed models, the shear retention mechanism along the crack surface correctly considered the smooth crack surfaces of HSC, and the confining effect of the column core was taken into account by modifying the concrete compressive model according to an appropriate confinement model for HSC. As part of the investigation, five large-scale HSC columns were constructed and tested under simulated seismic loading. The proposed numerical method was applied in predicting the seismic performance of various HSC columns tested in this research program and obtained from other research in the literature. The analytically predicted hysteretic behavior, ductility level, and failure mode of the columns showed reasonable agreement with experimental data. Copyright © 2011 Japan Concrete Institute.
Han S.I.,Seoyeong Engineering Co. |
Jo D.J.,Dongseo University |
Lee J.H.,Seoyeong Engineering Co. |
Jung Y.W.,Seoyeong Engineering Co. |
And 2 more authors.
Underground - The Way to the Future: Proceedings of the World Tunnel Congress, WTC 2013 | Year: 2013
Urban floods, classified as a technological disaster triggered by natural hazards due to climate change, have recently been caused by rapid urbanization and torrential rainfall. Underground facilities located in flood-prone areas are considerably vulnerable to flood disaster. Therefore, urban floods may cause not only serious property damage but also massive loss of lives. 'The Analytic Hierarchy Process' was adopted to examine the vulnerability of inland and underground inundation by analyzing the priority of flood-related influence factors. The results show that underground rainwater detention caverns are one of the most effective counter-measures for the prevention or mitigation of urban floods. In order to evaluate the mitigation effect of inundation, numerical simulation is performed using SWMM (Storm Water Management Model), which considers discharge with rainwater storage facilities in a new-town area. The simulation provides applicability for the flood mitigation system. An improved reinforcing technique in the pillar is developed to construct multi-placed rainwater detention caverns, with a comparative analysis of the strengthening effect through an experimental approach. Applying prestress switches the pillar stress back to an elastic state, securing the stability of the pillar. It is shown that the proposed pillar system has a practical advantage in that it provides the strength of in-situ ground, as a time and cost-saving structure, without relying on pre-cast concrete structure. © 2013 Taylor & Francis Group.
Suh J.,Seoul National University |
Choi Y.,Pennsylvania State University |
Roh T.-D.,Seoul National University |
Lee H.-J.,Seoyeong Engineering Co. |
Park H.-D.,Seoul National University
Environmental Earth Sciences | Year: 2011
The objective of this study is to perform a preliminary national-scale assessment of the landslide susceptibility of rock-cut slopes along expressways in Korea. A geographic information system (GIS) database was compiled based on data from topographical and geological maps, and rock-cut slope data, including the locations of past landslides. Seven factors (i. e., slope height, slope length, slope gradient, upper slope gradient, lithology, distance from nearest fault, and dip direction of slope) were extracted from the GIS database to assess the relationship between each factor and landslide events. Weight of evidence (WOE), analytic hierarchy process (AHP), and fuzzy logic methods, as well as hybrid methods, were used to establish the rating of classes for each factor, weightings for the factors, and to combine multiple factor layers into landslide-susceptibility maps. A comparison of the results obtained using several different methods, based on the area under curve technique, revealed that the WOE method showed the highest accuracy of 74%. The annual cost of traffic congestion resulting from slope failures was evaluated to identify those rock-cut slopes where detailed investigations and landslide warning systems are required. © 2010 Springer-Verlag.
Ahn J.,Pusan National University |
Jung J.,Pusan National University |
Kim S.,Pusan National University |
Han S.-I.,Seoyeong Engineering Co.
International Journal of GEOMATE | Year: 2014
The use of permeable pavement is one of the most promising tools to control runoff and water quality, therefore enabling low impact development (LID), along with several other benefits. The porosity of the permeable pavement is the most important property of the pavement in current state of the practice. In this article, the porosity of a pervious concrete sample made in laboratory was evaluated by two approaches: measuring weights and X-ray image analysis. Two different X-ray imaging apparatus, 2D and 3D, were used to construct cross-sectional planar images of a cylindrical pervious concrete sample. It was found that the porosity estimate from 2D X-ray was close to the results with measuring weights, but that of 3D X-ray was rather larger under Xray imaging configuration and image analysis technique used. The viability of using X-ray images to evaluate the pore characteristics of permeable pavement, and future applications are discussed. © 2014, International Journal of GEOMATE.
Lee Y.,Seoyeong Engineering Inc. |
Seo B.,SACS Korea Inc. |
Lee E.-T.,Chung - Ang University
International Journal of Steel Structures | Year: 2015
Offshore structures like jackets are exposed to various kinds of external loading conditions and examination of broader range of modes and natural frequencies are required for their dynamic analysis. In this study, four model reduction techniques — two modal truncation methods and two balanced truncation methods — are introduced and applied to a jacket structure. The reduction results are compared with those of the conventional Paz condensation methods. Four new methods show better fidelity, especially in high frequency ranges than the conventional methods. © 2014, Korean Society of Steel Construction and Springer-Verlag Berlin Heidelberg.
Sagong M.,Korea Railroad Research Institute |
Soo Park C.,Seoyeong Engineering Co. |
Lee B.,Hanyang University |
Chun B.-S.,Hanyang University
International Journal of Rock Mechanics and Mining Sciences | Year: 2012
The cross-hole seismic technique was used to identify the extent of the Excavation Damage Zone (EDZ) is in a test tunnel and in a tunnel under construction. For the cross-hole test, a new electro-mechanical impact-based transmitter was developed and tested. The transmitter was specially designed to generate appropriate impact energy and fit into a 45-mm rock bolt borehole. In the test tunnel, 79. P-wave rays were measured. The interval between the boreholes was 1.5. m. From the measured P-wave velocity, 2D tomography was constructed and the average velocity gradient curves at the offsets of 0.21, 0.57, 0.93, and 1.29. m were drawn. Given that the wave velocity gradient curves show spatial variation due to the quality of the rock mass, upper and lower bounds that delimit the P-wave velocity were drawn. The extent of the EDZ was determined as the depth at which the average velocity is lower than the lower bound. By applying this approach, the depth of the EDZ at the test tunnel was determined to be about 1.1. m from the tunnel surface. The cross-hole seismic measurement was compared with the condition of the extracted rock cores. A gray-scale image of the rock core was compared to the P-wave velocity profile. According to the image, disintegrated rock cores were present up to a depth of 1.1. m. From the seismic data and a visual inspection, a similar result was found. The same approach was applied in a tunnel under construction. From the site, the observed depth of the EDZ was about 0.9. m. In addition, because of the developed transmitter can generate S-waves, P- and S-wave velocities were measured and compared. The results show that S-waves can be successfully applied to identify an EDZ. The S-wave profile shows less scatter compared to a P-wave measurement. © 2012 Elsevier Ltd.