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Prof. Junsuk Kang
Seoul National University

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0 Hazard Mitigation
0 Urban Design
0 evidence based research
0 Disaster Mitigation
0 Soil-Structure Interaction

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Soil-Structure Interaction
Urban Design

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Journal article
Published: 29 March 2021 in International Journal of Disaster Risk Reduction
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Urban flooding damage is an increasing problem in cities worldwide and is only expected to become worse as urbanization and climate change continue. To prevent disasters and minimize loss of life and economic harm, government agencies have started implementing large-scale projects; however, budgetary constraints and overly optimistic designs have prevented the desired results. This study aims to prove that flood adaptation models using small-scale technologies can ameliorate the impact of torrential rainfall events. A new hydrology analysis model was applied to a district in Seoul, Korea that is prone to frequent floods. The results were encouraging and indicated the effectiveness of careful planning and urban design.

ACS Style

Younghun Choi; Junsuk Kang; Jaekyoung Kim. Urban flood adaptation planning for local governments: Hydrology analysis and optimization. International Journal of Disaster Risk Reduction 2021, 59, 102213 .

AMA Style

Younghun Choi, Junsuk Kang, Jaekyoung Kim. Urban flood adaptation planning for local governments: Hydrology analysis and optimization. International Journal of Disaster Risk Reduction. 2021; 59 ():102213.

Chicago/Turabian Style

Younghun Choi; Junsuk Kang; Jaekyoung Kim. 2021. "Urban flood adaptation planning for local governments: Hydrology analysis and optimization." International Journal of Disaster Risk Reduction 59, no. : 102213.

Journal article
Published: 31 December 2020 in Ceramics International
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An ultra-high temperature composite with superior mechanical characteristics was developed using zirconium diboride (ZrB2, 60% by volume), silicon carbide (SiC, 30% by volume), and tantalum carbide (TaC, 10% by volume), and its microstructure characteristics and mechanical properties were obtained experimentally by nanoindentation testing, X-ray diffraction, field emission scanning electron microscopy, X-ray fluorescence analysis, and X-ray photoelectron spectroscopy. Oxide contamination was eliminated, and the ceramic was densified to achieve a fully-dense ternary compound. To assess its performance in a typical real-world application, a finite element analysis was performed using the commercially available ABAQUS package for a one-bay one-story steel frame in which the prepared ceramic was used for the beam–column joint reinforcement end-plates; a good agreement was found with the results reported in the literature for comparable structures. The performance of a steel frame with a plate prepared from functionally graded materials located at the beam–column joint was then modeled in ABAQUS and subjected to the conditions recorded during a 1940 earthquake with a magnitude of 7.7. The results show that the utilized ceramic significantly enhanced the structural behavior of the reinforced concrete frame, confirming its potential utility in a wide range of industrial, structural, and medical applications.

ACS Style

Behzad Mohammadzadeh; Sunghoon Jung; Tae Hyung Lee; Joo Hwan Cha; Jongseong Park; Mehdi Shahedi Asl; Ho Won Jang; Sea-Hoon Lee; Mohammadreza Shokouhimehr; Junsuk Kang. Characterization and FEA evaluation of a ZrB2–SiC ceramic containing TaC for beam–column joint application. Ceramics International 2020, 47, 11438 -11450.

AMA Style

Behzad Mohammadzadeh, Sunghoon Jung, Tae Hyung Lee, Joo Hwan Cha, Jongseong Park, Mehdi Shahedi Asl, Ho Won Jang, Sea-Hoon Lee, Mohammadreza Shokouhimehr, Junsuk Kang. Characterization and FEA evaluation of a ZrB2–SiC ceramic containing TaC for beam–column joint application. Ceramics International. 2020; 47 (8):11438-11450.

Chicago/Turabian Style

Behzad Mohammadzadeh; Sunghoon Jung; Tae Hyung Lee; Joo Hwan Cha; Jongseong Park; Mehdi Shahedi Asl; Ho Won Jang; Sea-Hoon Lee; Mohammadreza Shokouhimehr; Junsuk Kang. 2020. "Characterization and FEA evaluation of a ZrB2–SiC ceramic containing TaC for beam–column joint application." Ceramics International 47, no. 8: 11438-11450.

Journal article
Published: 24 December 2020 in Sustainability
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The social and economic damages caused by climate change have increased rapidly over the last several decades, with increasing instances of heatwaves, floods, and extreme rainfall. In 2011, heavy rain of 110.5 mm/hr caused great damage to the Seoul Metropolitan Government. Most of the causes of flooding in modern cities include a sharp increase in non-permeable pavement and a lack of water circulation facilities. It is predicted that heavy rainfalls will occur in the future, causing large amounts of local damage. In this study, possible future flood damages were analyzed using climate change scenarios based on the Korean Peninsula. ArcGIS was adopted to perform analyses, and Huff curves were employed for precipitation analysis. Water tanks, permeable pavement, and ecological waterways were installed as mitigation technologies. These three technologies can contribute to flooding mitigation by increasing the rainwater storage capacity. This study suggests that all floods can be reduced by RCP 8.5 by 2050 and 2060. Although there will be run-off after 2050, it is believed that technology will significantly reduce the volume and possibility of floods. It is recommended that a one-year analysis should be conducted in consideration of the maintenance aspects that will arise in the future.

ACS Style

Jaekyoung Kim; Junsuk Kang. Analysis of Flood Damage in the Seoul Metropolitan Government Using Climate Change Scenarios and Mitigation Technologies. Sustainability 2020, 13, 105 .

AMA Style

Jaekyoung Kim, Junsuk Kang. Analysis of Flood Damage in the Seoul Metropolitan Government Using Climate Change Scenarios and Mitigation Technologies. Sustainability. 2020; 13 (1):105.

Chicago/Turabian Style

Jaekyoung Kim; Junsuk Kang. 2020. "Analysis of Flood Damage in the Seoul Metropolitan Government Using Climate Change Scenarios and Mitigation Technologies." Sustainability 13, no. 1: 105.

Journal article
Published: 26 October 2020 in Structures
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In this study, a novel simplified nonlinear dynamic method was presented to investigate the blast loaded plates. The material nonlinearity, strain rate, and various boundary conditions were included in the method together with plate geometry, scaled distance, and charge weight. The novelty of this work is that this method is easy-to-use while it covers all the important parameters affecting the blast-related dynamic responses of the isotropic plates. Equations of motion were achieved by applying the Navier solution to the dynamic governing equation of the plate. To include the material nonlinearity, the Ramberg-Osgood model, and hardening behavior were adopted. For the strain rate, the Cowper-Symonds relation was considered. Two types of boundary conditions were considered; simply supported and clamped plates. The scaled distance and charge weigh were included in the description of the blast load while the plate geometry was shown up in the stiffness and frequency of the plate. The method was validated by comparing the time history and maximum deflection of the plates obtained from the proposed method and those of the literature and finite element model through ABAQUS. Thereafter, a parametric study was carried out to examine the effects of plate aspect ratio, thickness, charge weight, and boundary conditions on the dynamic responses of the steel plates. The results showed that the plate deflection had a nonlinear relation with plate thickness, aspect ratio, and explosive charge while the clamped boundary condition resulted in a significant decrease in the maximum plate deflection.

ACS Style

Behzad Mohammadzadeh; Junsuk Kang; Seokbeen Im. Blast loaded plates: Simplified analytical nonlinear dynamic approach. Structures 2020, 28, 2034 -2046.

AMA Style

Behzad Mohammadzadeh, Junsuk Kang, Seokbeen Im. Blast loaded plates: Simplified analytical nonlinear dynamic approach. Structures. 2020; 28 ():2034-2046.

Chicago/Turabian Style

Behzad Mohammadzadeh; Junsuk Kang; Seokbeen Im. 2020. "Blast loaded plates: Simplified analytical nonlinear dynamic approach." Structures 28, no. : 2034-2046.

Journal article
Published: 27 July 2020 in Sustainability
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Increasing urbanization has highlighted the need for more green spaces in built-up areas, with considerable attention of vertical installations such as green walls and rooftop gardens. This study hypothesizes that the rooftop-garden-induced temperature reduction effects vary depending on the type of arrangements. Therefore, the objective of this study is to find the most efficient arrangement of the roof gardens for temperature reduction. This paper presents the results of a quantitative analysis of the temperature reduction effect of rooftop gardens installed on structures and sites on the campus of Seoul National University. An ENVI-Met simulation is utilized to analyze the effects of roads, buildings, green areas, and vacant land on temperature and humidity. The effects of the following five rooftop garden configurations were compared: extreme, linear (longitudinal), linear (transverse), checkerboard, and unrealized rooftop gardens. The extreme and linear (longitudinal) gardens achieved the maximum temperature reduction, −0.3 °C, while the lowest maximum reduction of −0.2 °C was achieved by the checkerboard pattern. Over larger areas, the greatest impact has been recorded in the mornings rather than in the afternoons. The results of this study will be useful for those planning and installing rooftop gardens at the district and city levels.

ACS Style

Jaekyoung Kim; Sang Yeob Lee; Junsuk Kang. Temperature Reduction Effects of Rooftop Garden Arrangements: A Case Study of Seoul National University. Sustainability 2020, 12, 6032 .

AMA Style

Jaekyoung Kim, Sang Yeob Lee, Junsuk Kang. Temperature Reduction Effects of Rooftop Garden Arrangements: A Case Study of Seoul National University. Sustainability. 2020; 12 (15):6032.

Chicago/Turabian Style

Jaekyoung Kim; Sang Yeob Lee; Junsuk Kang. 2020. "Temperature Reduction Effects of Rooftop Garden Arrangements: A Case Study of Seoul National University." Sustainability 12, no. 15: 6032.

Journal article
Published: 12 May 2020 in Materials
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This study presents a new ultra-high temperature composite fabricated by using zirconium diboride (ZrB2), silicon carbide (SiC), and tantalum carbide (TaC) with the volume ratios of 70%, 20%, and 10%, respectively. To attain this novel composite, an advanced processing technique of spark plasma sintering (SPS) was applied to produce ZrB2–SiC–TaC. The SPS manufacturing process was achieved under pressure of 30 MPa, at 2000 °C for 5 min. The micro/nanostructure and mechanical characteristics of the composite were clarified using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and nano-indentation. For further investigations of the product and its characteristics, X-ray fluorescence (XRF) analysis and X-ray photoelectron spectroscopy (XPS) were undertaken, and the main constituting components were provided. The composite was densified to obtain a fully-dense ternary; the oxide pollutions were wiped out. The mean values of 23,356; 403.5 GPa; and 3100 °C were obtained for the rigidity, elastic modulus, and thermal resistance of the ZrB2–SiC–TaC interface, respectively. To explore the practical application of the composite, the natural frequency of an aircraft wing considering three cases of materials: (i) with a leading edge made of ZrB2–SiC–TaC; (ii) the whole wing made of ZrB2–SiC–TaC; and (iii) the whole wing made of aluminum 2024-T3 were investigated employing a numerical finite element model (FEM) tool ABAQUS and compared with that of a wing of traditional materials. The precision of the method was verified by performing static analysis to obtain the responses of the wing including total deformation, equivalent stress, and strain. A comparison study of the results of this study and published literature clarified the validity of the FEM analysis of the current research. The composite produced in this study significantly can improve the vibrational responses and structural behavior of the aircraft’s wings.

ACS Style

Behzad Mohammadzadeh; Sunghoon Jung; Tae Hyung Lee; Quyet Van Le; Joo Hwan Cha; Ho Won Jang; Sea-Hoon Lee; Junsuk Kang; Mohammadreza Shokouhimehr. Manufacturing ZrB2–SiC–TaC Composite: Potential Application for Aircraft Wing Assessed by Frequency Analysis through Finite Element Model. Materials 2020, 13, 2213 .

AMA Style

Behzad Mohammadzadeh, Sunghoon Jung, Tae Hyung Lee, Quyet Van Le, Joo Hwan Cha, Ho Won Jang, Sea-Hoon Lee, Junsuk Kang, Mohammadreza Shokouhimehr. Manufacturing ZrB2–SiC–TaC Composite: Potential Application for Aircraft Wing Assessed by Frequency Analysis through Finite Element Model. Materials. 2020; 13 (10):2213.

Chicago/Turabian Style

Behzad Mohammadzadeh; Sunghoon Jung; Tae Hyung Lee; Quyet Van Le; Joo Hwan Cha; Ho Won Jang; Sea-Hoon Lee; Junsuk Kang; Mohammadreza Shokouhimehr. 2020. "Manufacturing ZrB2–SiC–TaC Composite: Potential Application for Aircraft Wing Assessed by Frequency Analysis through Finite Element Model." Materials 13, no. 10: 2213.

Journal article
Published: 23 March 2020 in Sustainability
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Due to climate change, heavy rainfall events that trigger landslips are becoming common. This study investigates patterns in the soil’s response to major rainfall events in mountainous areas and proposes a new approach for resilient disaster prevention technology and recovery based on the effect of soil runoff. Namhyeon-dong within Seoul was selected for the case study because of its vulnerable location between two mountains. A master plan was developed to cope with the predicted soil runoff based on the annual rainfall, local land use and a series of 10-year forecasts covering the period from 2021 to 2100. A total of 22 catchments in the study area were analyzed with Arc Hydro, an ArcGIS plug-in and appropriate technologies proposed to deal with the soil runoff likely to be experienced in each catchment in an extreme disaster. The resulting model was deemed adequate to deal with disasters during the period predicted to represent the highest risk, 2051–2060. The study’s findings will help to forecast disasters from flood that could impact residential areas in mountainous regions, to predict the magnitude of potential soil disasters in individual regions and develop design guidelines for disaster prevention technology based on the predicted amount of soil runoff.

ACS Style

Hyeji Jeon; Junsuk Kang. GIS Based Assessment and Design for Areas Vulnerable to Soil Disasters: Case Study of Namhyeun-dong, South Korea. Sustainability 2020, 12, 2516 .

AMA Style

Hyeji Jeon, Junsuk Kang. GIS Based Assessment and Design for Areas Vulnerable to Soil Disasters: Case Study of Namhyeun-dong, South Korea. Sustainability. 2020; 12 (6):2516.

Chicago/Turabian Style

Hyeji Jeon; Junsuk Kang. 2020. "GIS Based Assessment and Design for Areas Vulnerable to Soil Disasters: Case Study of Namhyeun-dong, South Korea." Sustainability 12, no. 6: 2516.

Journal article
Published: 01 February 2020 in Tunnelling and Underground Space Technology
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Over the years, considerable progress have been made for the improvement of the design criteria of buried culverts that increased in size and numbers with the development of information and technology in this field. This research investigates the effects of trench installation methods with expanded polystyrene (EPS) geofoam on the behavior of buried corrugated steel arch structure. A finite element analysis program, ABAQUS, was used to model and analyze the structure. For this study, an S275 corrugated steel with profiles of 152 × 51mm and 400 × 150mm, and thickness ranging from 3 mm to 7 mm was used. The structure was analyzed for three different configurations, namely; initial (without EPS geofoam), imperfect trench installation (ITI), and embedded trench installation (ETI) through three parametric analysis considering the influence of EPS geofoam’s geometry, thickness and corrugation profile of steel. The results from the finite element analyses revealed that ETI models reduced the earth pressure, deflection, and stress at the crown by 68%, 40%, and 39% on the average. It is recommended to conduct further study regarding ETI to validate the results and to further improved the design criteria of buried corrugated steel arch as it is expected to bring about cost reduction and stability for buried structures.

ACS Style

Ralph Raymond V. Santos; Junsuk Kang; Jong Sup Park. Effects of embedded trench installations using expanded polystyrene geofoam applied to buried corrugated steel arch structures. Tunnelling and Underground Space Technology 2020, 98, 103323 .

AMA Style

Ralph Raymond V. Santos, Junsuk Kang, Jong Sup Park. Effects of embedded trench installations using expanded polystyrene geofoam applied to buried corrugated steel arch structures. Tunnelling and Underground Space Technology. 2020; 98 ():103323.

Chicago/Turabian Style

Ralph Raymond V. Santos; Junsuk Kang; Jong Sup Park. 2020. "Effects of embedded trench installations using expanded polystyrene geofoam applied to buried corrugated steel arch structures." Tunnelling and Underground Space Technology 98, no. : 103323.

Journal article
Published: 21 January 2020 in Tunnelling and Underground Space Technology
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This analytical and experimental study examined the effects of using EPS Geofoam to reduce the earth pressure on underground arch structures. The finite element models developed using 2-D and 3-D approaches and nonlinear soil models were calibrated using field testing data. The behavior of the structure was investigated for varying thicknesses of the geofoam layer to determine the optimum level. The results of the finite element analysis revealed a load reduction of more than 80% when using the embedded trench installation (ETI) method. These results were within 10% of the experimentally measured values, demonstrating that the ETI method is an effective way to reduce earth pressure on underground arch structures.

ACS Style

Junsuk Kang; Hwangi Im; Jong Sup Park. The effect of load reduction on underground concrete arch structures in embedded trench installations. Tunnelling and Underground Space Technology 2020, 98, 103240 .

AMA Style

Junsuk Kang, Hwangi Im, Jong Sup Park. The effect of load reduction on underground concrete arch structures in embedded trench installations. Tunnelling and Underground Space Technology. 2020; 98 ():103240.

Chicago/Turabian Style

Junsuk Kang; Hwangi Im; Jong Sup Park. 2020. "The effect of load reduction on underground concrete arch structures in embedded trench installations." Tunnelling and Underground Space Technology 98, no. : 103240.

Journal article
Published: 01 October 2019 in Automation in Construction
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ACS Style

Pileun Kim; Jisoo Park; Yong K. Cho; Junsuk Kang. UAV-assisted autonomous mobile robot navigation for as-is 3D data collection and registration in cluttered environments. Automation in Construction 2019, 106, 1 .

AMA Style

Pileun Kim, Jisoo Park, Yong K. Cho, Junsuk Kang. UAV-assisted autonomous mobile robot navigation for as-is 3D data collection and registration in cluttered environments. Automation in Construction. 2019; 106 ():1.

Chicago/Turabian Style

Pileun Kim; Jisoo Park; Yong K. Cho; Junsuk Kang. 2019. "UAV-assisted autonomous mobile robot navigation for as-is 3D data collection and registration in cluttered environments." Automation in Construction 106, no. : 1.

Conference paper
Published: 13 June 2019 in Computing in Civil Engineering 2019
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Nuclear power plant disasters in the past century have led to the major economic loss, negative environmental impact, and danger to human lives. Disaster relief operations such as search and rescue, hazard detection, and damage assessment face significant challenges due to the difficulty in categorizing and analyzing damaged building structures. This study proposes an efficient method to generate a large number of 3D geometric models of a post-disaster nuclear power plant site using the Bullet physics engine. Two scenarios of nuclear power plant disasters, which are explosions due to reactor failure as well as earthquakes, are considered in this study. Different degrees of virtual forces are applied to the nuclear power plant site, and the resulting geometry of damaged structures are recorded. The generated database of damaged structures has many potential applications in object recognition, risk classification, and hazard analysis.

ACS Style

Jingdao Chen; Kinam Kim; Yong K. Cho; Joo Sung Lee; Byeol Kim; Yong Han Ahn; Junsuk Kang. Nuclear Power Plant Disaster Site Simulation Using Rigid Body Physics. Computing in Civil Engineering 2019 2019, 1 .

AMA Style

Jingdao Chen, Kinam Kim, Yong K. Cho, Joo Sung Lee, Byeol Kim, Yong Han Ahn, Junsuk Kang. Nuclear Power Plant Disaster Site Simulation Using Rigid Body Physics. Computing in Civil Engineering 2019. 2019; ():1.

Chicago/Turabian Style

Jingdao Chen; Kinam Kim; Yong K. Cho; Joo Sung Lee; Byeol Kim; Yong Han Ahn; Junsuk Kang. 2019. "Nuclear Power Plant Disaster Site Simulation Using Rigid Body Physics." Computing in Civil Engineering 2019 , no. : 1.

Journal article
Published: 29 March 2019 in Engineering Structures
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The objective of this study was to evaluate the performance of imperfect trench installations incorporating a soft material zone for buried concrete pipes. Traditionally, imperfect trench installations locate highly compressible lightweight materials such as expanded polystyrene foams, baled hay or straw above buried pipes in order to induce positive soil arching without trenches and hence reduce vertical top pressure and horizontal pressure. However, bottom pressure is not significantly reduced due to the additional downward shearing forces induced by transferring top pressure to the adjacent sides. Previous FE models that take account of plane strain elements suggest that soft zones surrounding pipes can markedly reduce bottom pressure, as well as the top and lateral pressures, but these models have not yet been validated by field tests and there have also been difficulties in evaluating the longitudinal behaviors of pipes. This study revisited the proposed use of soft zones using three-dimensional finite element analyses and validated the modeling methodologies using Valsangkar’s field tests. The results confirm that soft zones are a highly effective way to reduce the surrounding pressures on deeply buried concrete pipes, and the new finite element models presented here successfully overcome the limitations of the previous plane strain approach.

ACS Style

Junsuk Kang. Finite element analysis for deeply buried concrete pipes in proposed imperfect trench installations with expanded polystyrene (EPS) foams. Engineering Structures 2019, 189, 286 -295.

AMA Style

Junsuk Kang. Finite element analysis for deeply buried concrete pipes in proposed imperfect trench installations with expanded polystyrene (EPS) foams. Engineering Structures. 2019; 189 ():286-295.

Chicago/Turabian Style

Junsuk Kang. 2019. "Finite element analysis for deeply buried concrete pipes in proposed imperfect trench installations with expanded polystyrene (EPS) foams." Engineering Structures 189, no. : 286-295.

Journal article
Published: 13 March 2019 in International Journal of Concrete Structures and Materials
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The evaluation and design of concrete bridges in large part depend on the transverse distribution characteristics of the live load carried and the service level. The live load distribution for continuous concrete multicell box-girder bridges varies according to bridge configuration, so when designing such bridges, it is important to determine the maximum negative stress at the piers, the midspan positive (tensile) stress and the deflection of the bridge when subjected to live loads. This paper reports an extensive parametric study to determine the maximum stress, deflection, and moment distribution factors for two span multicell box-girder bridges based on a finite element analysis of 120 representative numerical model bridges. Bridge parameters were selected to extend the parameters and ranges of current live load distribution factors defined by AASHTO LRFD specifications. The results indicate that the span length, number of boxes, and the number of lanes all significantly affect the positive (tensile) and the negative (compression) stress distribution factors. A set of equations proposed to describe the behavior of such bridges under AASHTO LRFD live loads yielded results that agreed closely with the numerically derived results for the stress and deflection distribution factors.

ACS Style

Won Choi; Iman Mohseni; JongSup Park; Junsuk Kang. Development of Live Load Distribution Factor Equation for Concrete Multicell Box-Girder Bridges under Vehicle Loading. International Journal of Concrete Structures and Materials 2019, 13, 22 .

AMA Style

Won Choi, Iman Mohseni, JongSup Park, Junsuk Kang. Development of Live Load Distribution Factor Equation for Concrete Multicell Box-Girder Bridges under Vehicle Loading. International Journal of Concrete Structures and Materials. 2019; 13 (1):22.

Chicago/Turabian Style

Won Choi; Iman Mohseni; JongSup Park; Junsuk Kang. 2019. "Development of Live Load Distribution Factor Equation for Concrete Multicell Box-Girder Bridges under Vehicle Loading." International Journal of Concrete Structures and Materials 13, no. 1: 22.

Article
Published: 18 January 2019 in Paddy and Water Environment
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In South Korea, even snowfalls under the design snow loads are frequently known to cause significant deformations or failures of stand-alone cold-frame greenhouses. However, the possible causes of such events are not reflected in the structural design criteria currently used. To estimate the deformations related to structural failures, this study set up possible scenarios to be able to make the structural failures and examined the reasons through scaled-down experiments and nonlinear structural analyses. Hinge boundary conditions of supports and non-uniform snow loads occurred by the repetitive freeze–thaw cycles of the soils surrounding the supports without concrete foundations, and differences between internal and ambient temperatures, respectively, were considered. Two-dimensional scaled-down models of the greenhouses were constructed based on the similarity law. The experimental results were compared with those from nonlinear structural analyses of linear elastic–plastic models. For fixed boundary conditions at both ends and uniform snow loads, the relative errors of displacements between the experimentally obtained values and the results of the finite element analyses were within 6.10%. The results revealed that structural failures occurred in all cases with hinge boundary conditions for the supports at both ends for both uniform and non-uniform snow loads, but the greatest deformation behavior of the structure was observed with a hinge–hinge boundary condition and non-uniform snow loads where the horizontal displacement was similar to the vertical displacement. The temporary installations of diagonal braces in the greenhouses when heavy snowfalls are forecasted are therefore recommended to reduce the side sway.

ACS Style

Junsuk Kang; Jeongbae Jeon; Seongsoo Yoon; Won Choi. Failure conditions for stand-alone cold-frame greenhouse under snow loads. Paddy and Water Environment 2019, 17, 651 -663.

AMA Style

Junsuk Kang, Jeongbae Jeon, Seongsoo Yoon, Won Choi. Failure conditions for stand-alone cold-frame greenhouse under snow loads. Paddy and Water Environment. 2019; 17 (4):651-663.

Chicago/Turabian Style

Junsuk Kang; Jeongbae Jeon; Seongsoo Yoon; Won Choi. 2019. "Failure conditions for stand-alone cold-frame greenhouse under snow loads." Paddy and Water Environment 17, no. 4: 651-663.

Journal article
Published: 29 November 2018 in Automation in Construction
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Automatically registering 3D point clouds generated by unmanned aerial and ground vehicles (UAVs and UGVs) is challenging, as data is acquired at different locations with different sensors, consequently resulting in different spatial scales and occlusions. To address these problems, this study proposes a framework for the automated registration of UAV and UGV point clouds using 2D local feature points in the images taken from UAVs and UGVs. This study first conducted field experiments by varying the angles of the UAV camera to identify the optimal angle with which to detect sufficient points matching with the images taken by the UGV. As a result, this study identified that a combination of UAV images taken at 30° and 90° is appropriate for generating a sufficient number of matching points and attaining a reasonable level of precision. The UAV and UGV point clouds were initially scaled and registered with a transformation matrix computed from the 3D points corresponding to the 2D feature matching points. The initially aligned point clouds were subsequently adjusted by the Iterative Closest Point (ICP) algorithm, resulting in the root mean square error (RMSE) of 0.112 m. This promising result indicates that full automation of spatial data collection and registration from a scattered environment (e.g., construction or disaster sites) by UAVs and UGVs is feasible without human intervention.

ACS Style

Jisoo Park; Pileun Kim; Yong K. Cho; Junsuk Kang. Framework for automated registration of UAV and UGV point clouds using local features in images. Automation in Construction 2018, 98, 175 -182.

AMA Style

Jisoo Park, Pileun Kim, Yong K. Cho, Junsuk Kang. Framework for automated registration of UAV and UGV point clouds using local features in images. Automation in Construction. 2018; 98 ():175-182.

Chicago/Turabian Style

Jisoo Park; Pileun Kim; Yong K. Cho; Junsuk Kang. 2018. "Framework for automated registration of UAV and UGV point clouds using local features in images." Automation in Construction 98, no. : 175-182.

Journal article
Published: 21 September 2018 in Applied Sciences
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Because the methods used to compute the live load distribution for moment and shear force in modern highway bridges subjected to vehicle loading are generally constrained by their range of applicability, refined analysis methods are necessary when this range is exceeded or new materials are used. This study developed a simplified method to calculate the live load distribution factors for skewed composite slab-on-girder bridges with high-performance-steel (HPS) girders whose parameters exceed the range of applicability defined by the American Association of State Highway and Transportation Officials (AASHTO)’s Load and Resistance Factor Design (LRFD) specifications. Bridge databases containing information on actual bridges and prototype bridges constructed from three different types of steel and structural parameters that exceeded the range of applicability were developed and the bridge modeling verified using results reported for field tests of actual bridges. The resulting simplified equations for the live load distribution factors of shear force and bending moment were based on a rigorous statistical analysis of the data. The proposed equations provided comparable results to those obtained using finite element analysis, giving bridge engineers greater flexibility when designing bridges with structural parameters that are outside the range of applicability defined by AASHTO in terms of span length, skewness, and bridge width.

ACS Style

Iman Mohseni; Yong Kwon Cho; Junsuk Kang. Live Load Distribution Factors for Skew Stringer Bridges with High-Performance-Steel Girders under Truck Loads. Applied Sciences 2018, 8, 1717 .

AMA Style

Iman Mohseni, Yong Kwon Cho, Junsuk Kang. Live Load Distribution Factors for Skew Stringer Bridges with High-Performance-Steel Girders under Truck Loads. Applied Sciences. 2018; 8 (10):1717.

Chicago/Turabian Style

Iman Mohseni; Yong Kwon Cho; Junsuk Kang. 2018. "Live Load Distribution Factors for Skew Stringer Bridges with High-Performance-Steel Girders under Truck Loads." Applied Sciences 8, no. 10: 1717.

Research article
Published: 01 August 2018 in International Journal of Polymer Science
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This study evaluated the structural effects of applying fiber-reinforced polymer (FRP) wraps around their trunks to support old trees of national importance. High wind loads such as windstorms or hurricanes represent a major threat to tall trees, and researchers have assessed the structural behaviors of trees under wind loads using both analytical and experimental approaches. As yet, however, there is no widely accepted method to safely reinforce the structural stability of nationally and historically important tall trees subject to severe wind loads. Traditional reinforcing methodologies can actually damage supported areas as the supports are relatively stiff compared to the main trunk, introducing stressful interactions. FRP materials have high tensile strength, durability, and flexibility; hence, wrapping them around the surface of the tree trunk could enhance the overall stability of a tall tree subjected to high winds without sacrificing the tree’s visual aesthetics or damaging the bark. This study applied nonlinear finite element (FE) analyses to evaluate the complex structural behaviors of the wood and FRP wraps, both of which are anisotropic materials. The results revealed that FRP wraps offer a highly effective way to enhance the structural stability of tall trees with minimal cost.

ACS Style

Zheong Jun Yi; Junsuk Kang. Reinforcing the Structural Stability of Old Nationally Important Trees with FRP Wraps. International Journal of Polymer Science 2018, 2018, 1 -12.

AMA Style

Zheong Jun Yi, Junsuk Kang. Reinforcing the Structural Stability of Old Nationally Important Trees with FRP Wraps. International Journal of Polymer Science. 2018; 2018 ():1-12.

Chicago/Turabian Style

Zheong Jun Yi; Junsuk Kang. 2018. "Reinforcing the Structural Stability of Old Nationally Important Trees with FRP Wraps." International Journal of Polymer Science 2018, no. : 1-12.

Journal article
Published: 27 July 2018 in Applied Sciences
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This study assessed the structural performance of reinforced concrete (RC) arch bridges under strong ground motion. A detailed three-dimensional finite element model of a 400 m RC arch bridge with composite superstructure and double RC piers was developed and its behavior when subjected to strong earthquakes examined. Two sets of ground motion records were applied to simulate pulse-type near- and far-field motions. The inelastic behavior of the concrete elements was then evaluated via a seismic time history analysis. The concept of Demand to Capacity Ratios (DCR) was utilized to produce an initial estimate of the dynamic performance of the structure, emphasizing the importance of capacity distribution of force and bending moment within the RC arch and the springings and piers of the bridge. The results showed that the earthquake loads, broadly categorized as near- and far-field earthquake loads, changed a number of the bridge’s characteristics and hence its structural performance.

ACS Style

Iman Mohseni; Hamidreza Alinejad Lashkariani; Junsuk Kang; Thomas H.-K. Kang. Dynamic Response Evaluation of Long-Span Reinforced Arch Bridges Subjected to Near- and Far-Field Ground Motions. Applied Sciences 2018, 8, 1243 .

AMA Style

Iman Mohseni, Hamidreza Alinejad Lashkariani, Junsuk Kang, Thomas H.-K. Kang. Dynamic Response Evaluation of Long-Span Reinforced Arch Bridges Subjected to Near- and Far-Field Ground Motions. Applied Sciences. 2018; 8 (8):1243.

Chicago/Turabian Style

Iman Mohseni; Hamidreza Alinejad Lashkariani; Junsuk Kang; Thomas H.-K. Kang. 2018. "Dynamic Response Evaluation of Long-Span Reinforced Arch Bridges Subjected to Near- and Far-Field Ground Motions." Applied Sciences 8, no. 8: 1243.

Research article
Published: 10 July 2018 in Advances in Materials Science and Engineering
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In order to take into account the dynamic effects of moving vehicles, bridges are designed to carry static loads that are increased by dynamic impact (IFs) factors (or dynamic amplification factors) that are a function of either the span or the first flexural natural frequency of the bridge. However, this approach tends to produce very conservative designs as the IFs are calculated based on a relatively few general parameters, ignoring many significant bridge and truck dynamic characteristics. This paper presents a method for determining more realistic dynamic impact factors for skewed composite slab-on-girder bridges under AASHTO LRFD truck loading. An extensive parametric study of over 125 bridge prototypes examined key parameters, namely, the number of girders, number of lanes, skew angle, and span length. Based on the data generated by this analysis, appropriate expressions for dynamic impact factors for the longitudinal moment and deflection are proposed. In order to reduce the complexity of proposed expressions, the effects of road surface roughness on dynamic responses of bridge-vehicle interaction are considered in bridge modeling. The findings of this study are expected to help bridge engineers to design composite slab-on-girder bridges more reliably and economically and can also be used to reassess the safe live-load capacity of existing structures, potentially preventing the unnecessary posting or closing of busy highway bridges.

ACS Style

Iman Mohseni; Amin Ashin; Won Choi; Junsuk Kang. Development of Dynamic Impact Factor Expressions for Skewed Composite Concrete-Steel Slab-On-Girder Bridges. Advances in Materials Science and Engineering 2018, 2018, 1 -9.

AMA Style

Iman Mohseni, Amin Ashin, Won Choi, Junsuk Kang. Development of Dynamic Impact Factor Expressions for Skewed Composite Concrete-Steel Slab-On-Girder Bridges. Advances in Materials Science and Engineering. 2018; 2018 ():1-9.

Chicago/Turabian Style

Iman Mohseni; Amin Ashin; Won Choi; Junsuk Kang. 2018. "Development of Dynamic Impact Factor Expressions for Skewed Composite Concrete-Steel Slab-On-Girder Bridges." Advances in Materials Science and Engineering 2018, no. : 1-9.

Journal article
Published: 30 June 2018 in Journal of the Korean Society for Advanced Composite Structures
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ACS Style

Yeon-Wook Jeong; Zheong-Zun Yi; Sung-Jun Cho; Hwan-Gi Im; Jong-Sup Park; Jun-Suk Kang. Development of Innovative Application Technology of Geofoam for Sustainable Design of Eco-bridges under Deep Soil Cover. Journal of the Korean Society for Advanced Composite Structures 2018, 9, 58 -63.

AMA Style

Yeon-Wook Jeong, Zheong-Zun Yi, Sung-Jun Cho, Hwan-Gi Im, Jong-Sup Park, Jun-Suk Kang. Development of Innovative Application Technology of Geofoam for Sustainable Design of Eco-bridges under Deep Soil Cover. Journal of the Korean Society for Advanced Composite Structures. 2018; 9 (2):58-63.

Chicago/Turabian Style

Yeon-Wook Jeong; Zheong-Zun Yi; Sung-Jun Cho; Hwan-Gi Im; Jong-Sup Park; Jun-Suk Kang. 2018. "Development of Innovative Application Technology of Geofoam for Sustainable Design of Eco-bridges under Deep Soil Cover." Journal of the Korean Society for Advanced Composite Structures 9, no. 2: 58-63.