• Structural Engineering and Mechanics
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• v.63 no.1
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• pp.125-136
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• 2017

This study investigated the performance of a steel column standing on a reinforced concrete footing when it was subjected to collision of an eight-ton single unit truck. Finite element analyses of the structure with different connection schemes were performed using the finite element model of the truck, and the results showed that the behavior of the column subjected to the automobile impact depended largely on the column-footing connection detail. Various reinforcement schemes were investigated to mitigate the damage caused by the car impact. The probability of the model reinforced with a certain scheme to reach a given limit state was obtained by fragility analysis, and the effects of the combined reinforcement methods were investigated based on the equivalent fragility scheme. The analysis results showed that the reinforcement schemes such as increase of the pedestal area, decrease of the pedestal height, and the steel plate jacketing of the pedestal were effective in reducing the damage. As the speed of the automobile increased the contribution of the increase in the number of the anchor bolts and the dowel bars became more important to prevent crushing of the pedestal.

• International Journal of Highway Engineering
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• v.15 no.6
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• pp.49-60
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• 2013

PURPOSES : The evaluation of the pavement condition of the asphalt concrete pavement of No. 2 runway of Inchon International Airport through PMS, a supporting system for making a decision of pavement, maintenance and repair, was made, and the proper time for repair according to the PCI reduction rate was suggested. METHODS : By comparing and analyzing the evaluation results of pavements built in 2009, 2010, 2011, PCI change in each facility (No. 2 runway, C parallel taxiway, connection taxiway) was calculated. By applying the calculated change to PCI deduction rate model, the pavement condition of the target sections was estimated, and then the necessary section and time for repair were chosen. RESULTS : After careful consideration of the time for pavement and maintenance, based on the result of PCI prediction, it was estimated that the southern takeoff and landing section of No. 2 runway was required to be repaired in 2012; connection taxiway in 2013; and C parallel taxiway in 2014; however, the section which is the main moving route of connection taxiway and C parallel taxiway was needed to be repaired in 2012. CONCLUSIONS : For maintenance and repair of airport pavements, the optimal alternative should be chosen by considering economics and operability, via examining the time for repair and the aspect of management all together on the basis of this study.

• Korean Institute of Interior Design Journal
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• v.21 no.5
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• pp.355-362
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• 2012

Water Culture Pavilion was constructed as a part of dam construction and Four-major rivers restoration projects, which have the purpose to prevent damage of natural disaster, localized heavy rain and drought, and has several functions; promotion, education and region culture community. Exhibition space in this culture pavilion should have the excellent connection of various media, contents, and exhibition space because of limited space. The purpose of this study is to analyze flows, continuation and connection of exhibit space with the perspectives of the attribute of water and to suggest various content things, technical, spatial types. This study targets Four-major rivers Water Culture Pavilion in Korea and suggests exhibition presentation methods as analyzing contents, media and constituent of exhibition space for each pavilion exhibition. The result of this study is as follows : First, the circulation is common expressed attribute of water in these four water culture pavilion. The reason is that there is a connection between Four-major rivers restoration projects and the physical attribute of water circulating the steps of evaporation, condensation and precipitation. Second, each pavilion presents circulative solid exhibit, circulative background exhibit, circulative reflective exhibit based on circulation. These three types of exhibition is related the floor separation. Third, each pavilion exhibit zone shows the most circulation, solid, background, reflexibility through educational contents and promoting contents by using graphic, video, sound media.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.4
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• pp.397-402
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• 2005

A new control algorithm of soft starter is proposed for the reduction of the inrush current during the grid connection of the induction-type wind power generator. Currently, the fixed speed wind turbine using induction generator is the most popular wind generation system in Korea. It is shown that the amount of inrush current mainly depends on the control algorithm of the soft starter, a thyristor-based grid connection device. For the simulation study, a 600kw wind turbine simulation model is developed and the transient waveforms are investigated with conventional md proposed methods. Also experimental results using 3.7kW experimental set-up show that the peak value of inrush current is reduced about 20$\%$ using proposed algorithm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.251-252
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• 2006

As one of methods to increase the voltage rating of the flux-lock type SFCL, the fault current limiting characteristics of the flux-lock type SFCL with HTSC elements connected in series were analyzed. The initial fault current amplitudes in two SFCLs with the series connection of two HTSC elements and with single HTSC element were the same. In addition, the resistance amplitude of each HTSC element in SFCL with the series connection of two HTSC elements had the similar one in SFCL with single HTSC element. With increase of applying voltage, the unbalance of voltage between two HTSC elements in SFCL with the series connection of two HTSC elements disappeared.

• Steel and Composite Structures
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• v.48 no.3
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• pp.321-333
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• 2023

This paper proposes a comprehensive investigation on lateral stiffness of corner-supported steel modular frame using splice connection. A full-scale modular frame with two stacked steel modules under lateral load is tested. Ductile pattern in the transfer of lateral load is found in the final failure mode. Two types of lateral stiffness, including tangent stiffness and secant stiffness, are defined from the load-displacement due to the observed nonlinearity. The difference between these two types of stiffness is found around 20%. The comparisons between the experimental lateral stiffness and the predictions of classical methods are also conducted. The D-value method using hypothesis of independent case is a conservative option for predicting lateral stiffness, which is more recommended than method of contraflexural bending moment. Analyses on two classical short-rod models, including fix-rod model and pin-rod model, are further conducted. Results indicate that fix-rod model is more recommended than pin-rod model to simplify splice connection for simulation on lateral stiffness of modular frame in elastic design stage.

• Steel and Composite Structures
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• v.18 no.5
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• pp.1103-1117
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• 2015

It is known that material properties, connection quality and manufacturing methods are among the important factors directly affecting the behavior of steel connections and hence steel structures. The possible performance differences between a fabricated connection and its computer model may cause critical design problems for steel structures. Achieving a reliable design depends, however, on how accurately the material properties and relevant constitutive models are considered to characterize the behavior of structures. Conventionally, the stress and strain fields in structural steel connections are calculated using the finite elements method with assumed material properties and constitutive models. Because the conventional strain gages allow the measurement of deformation only at one point and direction for specific time duration, it is not possible to determine the general characteristics of stress-strain distributions in connections after the laboratory performance tests. In this study, a new method is introduced to measure displacement distribution of simple steel welded connections under tension tests. The method is based on analyzing digital images of connection specimens taken periodically during the laboratory tension test. By using this method, displacement distribution of steel connections can be calculated with an acceptable precision for the tested connections. Calculated displacements based on the digital image correlation method are compared with those calculated using the finite elements method.

• Journal of Korean Association for Spatial Structures
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• v.21 no.3
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• pp.69-76
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• 2021

Precast concrete (PC) modules have been increased its use in modular buildings due to their better seismic performance than steel modules. The main issue of the PC module is to ensure structural performance with appropriate connection methods. This study proposed a PC modular beam system for simple construction and improved structural and splicing performance. This modular system consisted of modules with steel plates inserted, and it is easy to construct by bolted connection. The steel plates play the role of tensile rebar and stirrup, which has the advantage of structural performance. The structural performance of the proposed PC modular beam system was evaluated by flexural test on one reinforced concrete (RC) beam specimen consisting of a monolithic, and two PC specimens with the proposed PC modular beam system. The results demonstrated that the proposed PC modular beam system achieved approximately 86% of the structural performance compared to the RC monolithic specimen, with similar ductility of approximately 1.06 fold greater.

• Journal of the Korea Institute of Building Construction
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• v.8 no.2
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• pp.81-87
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• 2008

High-rise building is taking a place as one of building types from apartment housings to commercial buildings. With taking in account of stability and durability, strength of used materials is increasing gradually in these high-rise buildings. According to this, frequency in use of SD500 re-bar is increasing gradually in high-rise buildings. However the study of SD500 re-bar is insufficient because SD500 re-bar started to be used for domestic buildings lately. Specially because there is no guide or study to refer to, people get into difficulties when to decide the method of re-bar connection in construction using SD500 re-bar. Accordingly in this study, it suggests the method of estimating the economical efficiency on SD500 re-bar connection, and conducts benefit/ cost analysis on lapped splice and coupler splice by applying AHP theory, and then presents its result. After to analyze re-bar diameter of D25, 29, and 32, finally we attained the result that the coupler splice is advantageous in all parts of benefit/ cost more than the lapped splice.

• Research in Community and Public Health Nursing
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• v.21 no.4
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• pp.448-457
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• 2010

Purpose: This study attempted to identify differences in elders' health status, quality of life, and satisfaction with customized home visiting health service depending on connection to volunteerism. Methods: A total of 400 subjects participated in this research. Data were collected from May to August of 2009 and the measurement tool used for this study was the house visiting health service recording sheet recommended by the Ministry of Health. Results: According to the results of this research on elders' health status in customized home visiting health service depending on connection to volunteerism, elders' connected to volunteerism positively showed a high level in functional health status areas such as daily life performance ability, instrumental daily life performance ability and Joint exercise capacity, and in the quality of life area. Conclusion: The results of this study can be utilized as complementary information when resources and networks are used for the effective management of house visiting health service subjects.