• Computational Structural Engineering
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• v.4 no.4
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• pp.79-89
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• 1991

New design method of R/C slab system based on finite element method has been presented. The proposed method can substitute inaccurate existing method, which has limitation in its application, and provide accurate and efficient design results for any type of slab system. Isoparametric plate element used in the slab design has been efficiently formulated to save computational time. Reinforcement has been determined by strength design method and compared with code minimum values. Graphical output through comprehensive contour map for resulting moments and designed steel areas has considerably facilitated design process. Accurate shear results from isoparametric plate element enabled to check punching shear in a proper manner. In addition to strength design criteria, serviceability has also been checked by utilizing newly developed inelastic deflection multiplier method. An example for circular slab with opening showed that the proposed method could be applied to design of irregular slab without any difficulty.

• Journal of the Korean Society for Railway
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• v.12 no.3
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• pp.405-411
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• 2009

Railway signaling system in a rapid transit using the ATC system the approved a speed limit to a train and a part of signaling system in a metro approved a distance which is possible to move. Referring to the way of transmitting train control information, there are the one transmitting it to the on-board system of a train using the direct track, the another transmitting it establishing an instrument, and the other transmitting an instrument by a railway track. The one is the method using the direct track as a conductor for composing the part of the track and attaining the information controlling a train by transmitting a signal to the track. It is used for the high-speed railway and the subway. The method using the track attains information by transmitting it to returned information, and the on-board system of a train attains it by magnetic coupling. Because many reinforcing bars on the concrete slab track are used, interaction between a rail and a reinforcing bar that is not produced on ballast track is made. Due to the interaction, the electric characteristic of rail is changed. In the current paper, we numerically computed the coupling coefficient between the rail and the reinforcing bar based on the concrete slab track throughout the model related to the rail and the reinforcing bar using the concrete slab track that is used in the second interval of the Gyeongbu high-speed railway, and we defined the coupling coefficient not changed in the electric characteristic of rail in the condition that there is no interaction between the rail and the reinforcing bar.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.5
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• pp.511-521
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• 2015

The thermal bridge occurring in a building influences its thermal performance and durability. The domestic typical multi-unit residential buildings suffer thermal losses resulting from thermal bridges of the balcony slab. To minimize the thermal loss between inside and outside of the balcony slab, thermal bridge breaker(TBB) systems have been developed and applied in building construction. Although thermal bridge breaker systems for reinforced concrete(RC) wall-slab joints can improve the thermal performance of a building, it is necessary to verify the structural performance of TBB systems whether they provide proper resistance for cyclic loading. In order to investigate the structural characteristics of TBB systems embedded in RC slabs, cyclic tests of wall-slab joints were performed by applying two reversed cycles at each up to 30 cycles. The test results show that the RC slabs embedding TBBS systems can present excellent structural performance and the maximum moment capacity, energy dissipation capacity and ductility of TBBs systems are enhanced compared to those of the typical RC slabs.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.1 s.53
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• pp.106-114
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• 2009

The steel design based on the width of transverse crack which is the major factor to affect a long-term performance of continuously reinforced concrete pavement was developed. For this study, twenty-one cities of Texas were selected and the temperature data was collected at those locations during the past ten years. From the data, zero-stress temperatures were calculated by the PavePro program and the widths of transverse crack were analyzed by the CRCP program. The variables used to this numerical analysis were slab thickness, coefficient of thermal expansion of concrete, steel ratio, and design temperature. The total of 448 factorial runs were made and the regression analysis was performed using the results. Steel ratios from the regression equations were backcalculated and a steel design table was proposed.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.341-349
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• 2012

Recently, as structures in Korea and other countries become much taller, larger, and more specialized, concrete used for constructions of these structures is required to have high performance characteristics. Especially, seismic performance of concrete must be improved to resist cyclic loading from earthquakes. Consequently, this study was performed to focus on developing optimal mixtures of high ductile fiber reinforced mortar with high ductility and durability, which have good serviceability, stability and reliability performances. Eventually, this material is expected to improve seismic performance of concrete structures such as load carrying capacity, ductility capacity, and energy dissipation capacity when applied to critical regions of flat plate slab-column joint. Ultimately, this research is intended to develop a material for basic designs and practical constructions of reinforced concrete structures. Test results showed that the maximum load carrying capacity, the ductility capacity, and the energy dissipation capacity of the test specimens titled RCFPP series were increased by 15%~34%, by 33%~37%, and by 2.14 times, respectively, compared to those of the standard specimen titled SRCFP.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.127-128
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• 2010

The purpose of this study is to evaluate the seismic performance of gravity-designed post tensioned (PT) flat plate frames with and without slab bottom reinforcement passing through the column. For the PT flat plate frames, the slab bottom reinforcement is often omitted since the requirement for the slab bottom reinforcement for PT flat plates is not clearly specified in ACI 318-08. This study evaluates the seismic performance of the model frames was evaluated by conducting nonlinear time history analysis. The seismic performance of PT flat plate frames is significantly improved by placing slab bottom reinforcement passing through the column.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4A
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• pp.311-321
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• 2011

To analysis the effect of reinforcement ratio and impact velocity on local damage, a series of impact analyses are performed to predict local effects. According to these results, the reinforcement ratio has no effect on the penetration depth and perforation thickness, but notable change to the scabbing area were observed. The higher the missile velocity becomes, the greater the degree of local damage to the reinforced concrete slabs is. Analysis results will be useful in the impact-resistance design of containment buildings and structures.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.4
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• pp.360-367
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• 2009

The acoustic emission(AE) behavior of reinforced concrete slab under flexural loading was investigated to assess the integrity. This study was aimed at identifying the characteristics of AE response associated with damage development. By applying cyclic loading in various load steps, it was able to differentiate each AE source such as distributed micro crack initiation, friction, flexural crack and localized diagonal tension crack. The secondary peak and the change of AE hit rate gave valuable criteria fur assessment. From the analysis of the felicity ratio, furthermore, it was shown that this values can be used for evaluating the degree of concrete damage. Based on the experimental results, this approach for practical AE application may provide a promising method for estimating the level of damage and distress in concrete structures.

• Journal of the Korean Society for Railway
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• v.8 no.4
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• pp.293-298
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• 2005

A method is described for predicting crack with and spacing in Steel Fiber Reinforced Concrete (SFRC). The crack behavior of SFRC influenced by longitudinal reinforcement ratio, volume and type of sleet fiber, strength of concrete. It can be observed from experimental results that addition of steel fiber to reinforced concrete beam reduces crack width in serviceability limit stales. The proposed method predicts crack widths in cracking stage of the beam. Calculated crack widths obtained for reinforced concrete beams and different volume and type of steel fiber, strength of concrete showed good agreement with experimental results.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2072-2076
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• 2011

철도 시스템에서 철도궤도와 레일은 주요한 신호 시스템의 일부로 사용되고 있으나 콘크리트 슬래브 궤도 내부의 철근으로 인한 신호전류 감소, 교란 등을 방지하기 위해 과도한 절연작업이 필요하다. 본 연구에서는 국내에서 기 개발된 프리캐스트 슬래브 궤도의 횡방향 철근을 GFRP 보강근으로 대체하여 절연작업의 감소를 가능하게 하였다. GFRP로 보강된 프리캐스트 슬래브 궤도의 설계과정과 정적 휨 시험과 단부의 연결철근 인발 시험을 통한 거동 분석 및 고찰 내용을 제시하였다. 휨 시험과 실스케일 인발 시험의 결과 정적 휨 강도는 정립된 설계법에 의해 적절한 강도를 가지고 있으나 기 개발된 연결철근의 위치와 형태는 온도 또는 수축으로 인해 발생할 수 있는 축력을 저항할 수 없음을 확인하였다.