• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.37-45
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• 2013

In this study, the resistance of various reinforced concrete (RC) slabs subjected to contact detonation was assessed. In order to enhance the blast resistance, fibers and external FRP sheets were reinforced to RC slabs. In the experiment, the $2,000{\times}1,000{\times}100mm$ sized RC slabs were fabricated using normal concrete (NC), steel fiber reinforced concrete (SFRC), polyvinyl alcohol fiber reinforced cementitious composite (PVA FRCC), and ultra-high performance cementitious composites (UHPCC). The damage levels of RC slabs subjected to contact detonation were evaluated by measuring the diameter and depth of crater, spall and breach. The experimental results were compared to the analyzed data using LS-DYNA program and three different prediction equations. The diameter and depth of crater, spall and breach were able to be predicted using LS-DYNA program approximately. The damage process of RC slabs under blast load was also well expressed. Three prediction equations suggested by other researchers had limitations to apply in terms of empirical approaches, therefore it needs further research to set more analytical considerations.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.204-211
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• 2009

In this study, the optimal method is applied to strengthening of RC hollow slab bridges using external prestressing. The Queen-post and King-post shapes are considered to find the effective tendon configurations. In order to achieve the objective rating factor, the optimal configurations and tendon forces are obtained by using the Sequential Unconstrained Minimization Technique (SUMT). The object function for optimal strengthening is constituted with the dimensionless function of material costs. The constraints are formulated by design specification and the rating factor. The validity of this study is presented by the analysis of the results of strengthening of the RC hollow slab bridges.

• Journal of the Society of Disaster Information
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• v.10 no.2
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• pp.312-318
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• 2014

Recent building structures are superior in its ability but they are light weight and long span, and so have problems of vibration. In general, the serviceability of RC slabs was known to be good against vibration because of its hardness. However, recent high-rise apartment slabs are mostly light and long, the serviceability of RC slabs due to vibration could be a problem. In this paper, a basic investigation about vibration problems of RC slabs was performed. Basic information and its influence on vibrations of RC slabs were revealed. Also, its serviceability against vibration was examined. Many tests were conducted for natural frequency of building, for example load of two persons walking and one person leaping etc.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.543-553
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• 2023

This study was conducted to propose a simple method to evaluate the load-carrying capacity of RC slab bridges, which have been most frequently constructed in Korea. A number of RC slab bridges have been considerably deteriorated associate with the long service year. However, since these bridges are not included in the 1st and 2nd class infrastructures due to their short span length, they have been relatively neglected compared to other bridge types in terms of safety management. In the previous theoretical study, a process (draft) was proposed for evaluating the damage of RC slab bridges using the relationship between the displacement response ratio and the stiffness reduction rate derived by the measured displacement and natural frequency. In this paper, to verify the validity of the proposed damage evaluation process (draft), the results to the actual bridges were compared with the safety grade and the Matsui's deterioration index. In addition, to enhance the practical applicability of the existing process (draft), an improved method approximately evaluating the load-carrying capacity using only the measured natural frequency was presented. If an error of 10% of the load-carrying capacity is allowed, it is judged that the proposed damage evaluation process can be appropriately used not only for evaluating the safety of RC slab bridges, but also for determining priorities for their maintenance.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.37-38
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• 2010

The deflection of RC half slabs with rids was much smaller than that of the conventional RC half slabs. In this study, the deflection of RC half slabs with rids was calculated by using a FE method and a elastic analysis. The deflections predicted by the FE method and the elastic analysis predicted the deflection measured by tested slabs with reasonable agreement.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.61-64
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• 2008

A combination of CFT column and RC flat plate without formworks is very effectively rapid constructions. This paper verified the lateral resisting capacity of CFT column-RC flat plate exterior connection in comparison with general RC column-flat plate connection and detected moment capacity and ductility capacity of connection according to moment-displacement ratio. We made and tested specimens which have different variables respectively and as a result derive a following conclusion. In CFT-E2 specimen a critical section was extended and maximum moment increased 20% respectively in comparison to general RC column specimen. In BME and CFT-E1 specimens generally shear governed behaviors and CFT-E2 specimen complemented with seismic band, flexure behavior region of slab was extended and also ductility ratio and energy absorptance increased.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.95-96
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• 2010

This paper presents the crack control of reinforcement concrete composite slabs which were produced with the extruded ECC panel. Cracking control performance was evaluated based on the flexural tests on real scale one-way slabs manufactured with or without ECC panel.

• Journal of Urban Science
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• v.11 no.1
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• pp.9-13
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• 2022

Currently, RC slab bridges in use in Korea account for most of the total bridges, and bridges with a service life of 20 years or more account for about 75%. However, most of these RC slab bridges have a span of less than 20m and are not included in the first and second types of facilities, so maintenance is very neglected. Therefore, in this study, field load test is performed on an aged RC slab bridge, and the performance evaluation is performed based on the structural response results (deflection, impact coefficient, natural frequency, etc.) of the bridge obtained through field load test. In addition, the performance evaluation results obtained through the load test are intended to be used as basic data for the damage evaluation process of the bridge currently under development.

• Journal of Korean Society of Steel Construction
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• v.25 no.6
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• pp.623-634
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• 2013

In this study, the structure behavior of RC slab and SC shear wall connection was investigated. Also experimental study was performed to evaluate the factor of safety of demand shear connection strength in KEPIC SNG Standard. As a result, shear friction strength of connection was known about 300kN and shear strength of rebar increased according to the displacement increase. With the installment of the lower rebars, 40% shear strength increased compared to the non-rebar specimen.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.65-68
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• 2008

This paper verified the lateral resisting capacity of CFT column-RC flat plate connection in comparison with general RC column-flat plate connection and detected moment capacity and ductility capacity of connection according to lateral force-displacement ratio. We made and tested specimens which have different variables respectively and as a result derive a following conclusion. In CFT specimen a critical section was extended and initial stiffness and moment increased 35%, 25$^{\sim}$35% respectively in comparison to general RC column specimen. In all specimens generally shear governed behaviors and in CFT specimen complemented with seismic band, flexure behavior region of slab was extended and also ductility ratio and energy absorptance increased.