• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.107-108
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• 2019

The interlayer noise of the apartment house is a typical problem that reduces the quality of the residential environment. Therefore, many researchers have developed soundproofing materials that blocks noise between floors. However, most development technologies do not have the noise cut-off effect felt by residents, and may also have a defect in long-term deflection. In this respect, this study developed high-performance interlayer soundproofing material that can overcome existing problems. The developed technology has the noise reduction effect experienced by the residents and it has high durability without long-term deflection. Therefore, high-performance interlayer soundproofing material is expected to contribute to reducing disputes over noise between floors of apartment residents.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1A
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• pp.15-24
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• 2008

This paper presents the analytical method for the long-term behavior of simply supported composite beams with precast decks prestressed in the longitudinal direction. The objectives of time-dependent analysis are to estimate losses of prestress on the concrete slab and long-term deflection due to creep and shrinkage of concrete, relaxation of prestressing steel. Also, the time-dependent analysis was carried out using the presented analytical method to evaluate the effects of several parameters on the long-term behavior of composite bridge with precast deck, including geometrical shapes of composite beams, compressive strength of concrete and magnitude of initial prestress. The results of the analysis indicated that, in the effects of geometrical shapes of composite beams, the main parameters affecting the losses of prestress and the long-term deflection were the cross sectional area and the moment of inertia of steel beam, respectively. Finally, the determination method for the required initial prestress was proposed by evaluation of the loss characteristics due to shrinkage and creep of concrete.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.799-800
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.232-233
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• 2011

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.103-110
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• 2018

The long-term flexural behavior of reinforced concrete (RC) beams strengthened with an iron based-shape memory alloys (Fe-SMAs) by a near-surface mounted (NSM) method was evaluated. The pre-strained values of 2% and 4% and introduced prestressing force by an activation of a shape memory effect of the Fe-SMA strengthening material were considered as experimental variables. Deflections at the center of the RC beams were measured for six months after the 1 tonf concrete weight was loaded on the beam. Experimental results show that the deflections decreased because of the increased flexural stiffness of beams strengthened with the Fe-SMA strips. On the contrary, with increased pre-strained values, the deflection increased due to stiffness reduction of the strengthening material. It was confirmed that the specimens incorporating the prestressed force showed the deflection reduction of about 30%, compared to the ones without the prestressed force.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.12
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• pp.1250-1256
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• 2012

Resilient materials are used to reduce the floor impact sound in apartment buildings. Since an on-dol layer is installed in the resilient materials' upper part, thickness deformation can be occur in the resilient material. It is necessary to check a thickness deformation grade for a long period of time. In this research, we measured thickness deformation over 400th day to the resilient materials(EPP, EPS, EVA) which is used in Korea. Although there was a difference according to the kind of measurement test specimens, it became clear that thickness was decreases as to time increased. The thickness deformation grade of ten years after was calculated based on the thickness measurement result. Compare with the calculated result and result of ISO 20392. Larger thickness deformation occurred in the measurement result of these research findings compare with the ISO standard.

• Magazine of the Korea Concrete Institute
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• v.10 no.1
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• pp.179-188
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• 1998

캔틸레버 공법으로 시공되는 프리스트레스트 콘크리트 박스거더 교량의 구조적 거동은 단계적 시공에 따른 구조물의 순차적 변화 및 콘크리트의 재료적 특성에 의해 시간 의존적 거동을 나타낸다. 콘크리트의 시간의존적 특성, 즉 콘크리트의 크리프 및 건조수축 특성은 현장타설 세그멘탈 캔딜레버공법으로 가설되는 콘크리트 교량의 설계 및 시공에서 매우 중요한 역할을 한다. 본 연구에서는 콘크리트의 크리프 및 건조수축 특성이 교량의 시간의존적 거동, 특히 처짐 및 텐던응력예측에 미치는 영향을 연구하였다. 교량해석은 본 연구진에 의해 개발된 프리스트레스트 콘크리트 교량해석기법 및 프로그램을 이용하여 크리프의 ACI 모델, CEB-FIB모델, 그리고 국내 도로교 시방서 모델을 고려하여 해석하였다. 해석결과 최종크리프 값의 크기에 따라 장기처짐의 발생량이 차이가 큰 것으로 나타나고 있으며, 최종건조수축량과 상대습도도 영향을 주는 것으로 나타났다. 또한 ACI 모델과 CEB-FIB모델간에도 차이가 큰 것으로 나타나 실제교량의 크리프 특성 및 건조수축 특성의 정확한 예측이 교량의 정밀시공 및 거동예측에 매우 중요한 것으로 나타나고 있다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.159-160
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• 2020

Flat plate structures are designed in the form of long span due to the development of construction materials and the improvement of construction technology. However, a high-rise structure of a flat plate of 50 less floors is constructed without detailed review of the inequality shortening, long-term deflection of the slab, and cracks. Therefore, it is possible to examine the case of defects in the structure due to deformation and damage of non-structures such as crack and leak, deflection of the door frame, and deformation of equipment ducts. In this study, it is a high-rise structure, and the inequality shortening and long-term deflection of the slab of the flat plate structure were evaluated through finite element analysis, and it was confirmed that prior precision analysis and correction during construction is necessary.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.30-38
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• 2017

Recently, research on the development of a composite slab system for shorting the construction period by simplifying the process by omitting the form work and the reinforcement placing is underway. The purpose of this study is to evaluate the long-term behavior of a simplified slab system that replaces the form work and tensile reinforcement using structural deck-plate and replaces the temperature reinforcement using steel fiber reinforced concrete. In the conventional composite deck-plate slab method, w.w.f is generally used for crack control by drying shrinkage. But previous research results by various researchers were pointed out it is not effective to control the shrinkage and temperature cracking. In this study, the long-term cracking and structural behavior of steel fiber reinforced deck plate slab specimen with two continuous spans constructed under typical load conditions were evaluated. Experimental results showed that the number and width of long-term cracks decreased remarkably in the simplified slab specimen, and the deflection was also decreased compared with conventional RC slab specimen. However, in the continuous end of the slab where the negative moment is applied, it is analyzed that reinforced details are necessary to control the crack width in the service load and to recover deflection at load removal.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.419-421
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• 2012

높이 2.5m의 콘크리트 플로팅 함체에 3층 규모의 상부골조가 있는 예제에 대해 동적 유체 해석과 정적 구조 해석을 수행하고 그 결과에 따라 종방향설계, 함체의 상부 및 하부 슬래브, 외벽 및 격벽에 대한 설계를 수행하였다. 환경 하중은 새만금 방파제 내부 정수역을 기준으로 파도주기 3.7초, 유의파고 1.0m와 풍속 40m/s를 적용하였으며, 하중조합은 ASCE/SEI 7-10을 기준으로 설계 하였다. 예제 구조물에 대한 설계 결과 고정하중에 의한 영향이 활하중 및 파랑하중에 비해 크게 나타났으며, 이로 인해 중앙부의 철근비가 높아지므로 고정하중을 감소시키는 방안을 검토하여야 함을 확인하였다. 또한 보의 지속하중에 의한 장기처짐과 추가적인 활하중에 의한 순간 처짐의 값이 허용 처짐값보다 크므로 보에서의 프리스트레싱을 고려해야 할 것으로 판단된다.