• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.433-439
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• 2007

A ubiquitous environment in construction requires integrating hardware and software systems. Currently the Construction System Integration Lab (CSIL) at Pusan National University is currently studying the application of ubiquitous technology for better communication in the construction process. In this paper, a pilot of Ubiquitous Concrete Pour System (u-CPS) has been presented to demonstrate the effectiveness of data exchange in the concrete pour process. The u-CPS environment takes advantage of the RFID technology for collecting construction data. The pilot can automatically generate the data for concrete pour work such as departure time, arrival time, concrete pour time. Construction managers can keep track of the progress of concrete pour work using the information. A case study was done for a building construction using the pilot system, the result of which demonstrated that the RFID-base system can help improve the effectiveness of data communication during the concrete pour process.

• 한국건설관리학회논문집
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• 제8권3호
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• pp.142-149
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• 2007

최근 유비쿼터스 관련 기술을 건설관리에 적용하고자 하는 노력이 진행되고 있다 유비쿼터스 기술을 건설관리에 도입하기 위해서는 웹 환경의 사용자 환경뿐만 아니라 하드웨어와 소프트웨어 기술을 접목해야 한다. 하드웨어와 소프트웨어를 융합함으로써 건설 프로세스 상에서 생성되는 데이터를 실시간으로 획득하여 신속하게 진도현황을 파악할 수 있다. 본 논문의 목적은 RFID (Radio Frequency Identification) 기술을 응용하여 콘크리트 타설 프로세스 상의 정보관리를 개선하는 것이다. 연구 수행을 위해서 RFID 기술을 기반으로 하는 콘크리트 모니터링 프로세스를 수립했다. 또한 RFID 리더기와 태그를 사용하여 콘크리트 타설 프로세스 상에서 생성되는 데이터를 자동으로 처리하는 u-CPS (Ubiquitous Concrete Pour System)의 프로토타입을 개발했으며, 아파트 타설현장에 적용되어 시스템의 적용성을 검증했다. H-CPS는 콘크리트 타설 프로세스 상에서 생산과 품질정보를 제공하여 레미콘 트럭의 배치간격 조정 등 원활한 작업계획을 세우기 위한 의사결정 정보를 제공하는 것으로 나타났다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.529-532
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• 2006

건설산업에서 설계 ${\cdot}$ 시공 역량을 발전시키고, 건설관리의 선진화를 달성하기 위해서 유비쿼터스 기술의 필요성이 대두되고 있다. 유비쿼터스를 응용하는 환경은 생산성과 관리효율 향상을 위한 많은 기회를 가져올 것으로 예상된다. 부산대학교 건설시스템연구실에서 실시하고 있는 본 연구는 기존 콘크리트 타설 프로세스에 유비쿼터스 기술 중 하나인 RFID 기술을 적용하여 콘크리트 타설 시 생산과 품질 관리의 효과를 높이는 방안을 제시하는 것을 목적으로 하고 있다. 시범현장에 대한 테스트를 위해서 RFID 기술을 접목한 사용자 환경을 개발했으며, RFID 장비를 배치 플랜트와 현장에 배치하여 콘크리트 타설 작업을 모니터링 했다. 현장 테스트를 통해서 배치 플랜트와 시공현장 간 커뮤니케이션을 향상시키고, 결과적으로 생산성 및 품질관리의 효과를 높일 수 있는 것으로 평가됐다.

• 화약ㆍ발파
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• 제16권4호
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• pp.18-28
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• 1998

Effects of blasting vibrations on curing concrete have not been well studied. As a result, unreasonable and strong blasting vibration constraints have been placed on blasting when it occur in the vicinity of curing concrete. To study the effects of blasting on curing concrete blocks of $33.3{\times}27.7{\times}16.2cm$ were molded and placed on the quarry. Several sets of concrete blocks were subjected separately to peak vibrations of 0.25, 0.5, 1.0, 5.0 and 10cm/sec. The impulses of blasting vibrations were applied with thirty-minute intervals. Along with unvibrated concrete blocks, the vibrated concrete samples cored with 60.3mm in diameter were measured for elastic moduli, sonic velocity and uniaxial compressive strength. Test results can be summarized as follows; 1. The blasting vibrations between 6 and 8 hours after pour generally lowered on the uniaxial compressive strength of the concrete. 2. A low blasting vibration of 0.25cm/sec did not affect the uniaxial compressive strength. As the magnitude of the blasting vibration increases, compressive strength of concrete is decreased. 3. Physical properties of the P-wave velocity, Young’s modulus, and Poisson's ratio showed a weakly decreasing trend in the concrete blocks vibrated between 6 and 8 hours after pour.

• 터널과지하공간
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• 제5권2호
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• pp.134-143
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• 1995

Effects of blasting vibrations on curing concrete have not been well studied. As a result, unreasonable and strong blasting vibration constraints have been placed on blasting when it occurs in the vicinity of curing concrete. To study the effects of blasting on curing concrete blocks of 33.3X27.7X16.2 cm were molded and placed on the quarry. Several sets of concrete blocks were subjected separately to peak vibrations of 0.25, 0.5. 1.0, 5.0, and 10cm/sec. The impulses of blasting vibrations were applied with thirty-minute intervals. Along with unvibrated concrete blocks, the vibrated concrete samples cored with 60.3 mm in diameter were measured for elastic moduli, sonic velocity and uniaxial compressive strength. Test results can be summarized as follows; 1. The blasting vibrations between 6 and 8 hours after pour generally lowered on the uniaxial compressive strength of the concrete. 2. A low blasting vibration of 0.25 cm/sec did not affect the uniaxial compressive strength. As the magnitude of the blasting vibration increases, compressive strength of concrete is decreased. 3. Physical properties of the P-wave velocity, Young's modulus, and Poisson's ratio showed a weakly decreasing trend in the concrete blocks vibrated between 6 and 8 hours after pour.

• Advances in concrete construction
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• 제16권2호
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• pp.107-117
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• 2023

Textile-reinforced concrete composite (TRC) is a new alternative material that can satisfy sustainable development needs in the civil engineering field. Its mechanical behaviour and properties have been identified from the experimental works. However, it is necessary for a numerical approach to consider the effect of the parameters on TRC's behaviour with lower analysis duration and cost related to the experiment. This paper presents obtained results of the numerical modelling for TRC composite using the cracking model for the cementitious matrix in TRC. As a result, the TRC composite exhibited a strain-hardening behaviour with the cracking phase characterized by the drops in tensile stress on the stress-strain curve. This model also showed the failure mode by multi-cracking on the TRC specimen surface. Furthermore, the parametric studies showed the effect of several parameters on the TRC tensile behaviour, as the reinforcement ratio, the length and position of the deformation measurement zone, and elevated temperatures. These numerical results were compared with the experiment and showed a remarkable agreement for all cases of this study.

• 한국구조물진단유지관리공학회 논문집
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• 제3권2호
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• pp.205-212
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• 1999

Recently, unexpected cracks in the concrete deck slab of composite steel bridges have been widely reported at an early age of concrete placing due to the concrete placing sequence and methods. Accordingly, the analytical research was carried out to verify the negative moment at an internal supports due to the several concrete pouring sequence and to determine the reasonable concrete placing method on the deck slab of composite steel bridge. The results show that the conventional concrete-placing method, which pours concrete first on the positive moment regions and then negative regions, leads to the minimum moment at an internal supports. However, the conventional method produces two impractical construction joints on every spans and makes field engineer to pour concrete continuously. In conclusion, this concrete-placing method was verified to be reasonable only when the construction joint was placed at the $\frac{5}{8}l{\sim}\frac{6}{8}l$ location of the middle span.

• Structural Engineering and Mechanics
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• 제50권3호
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• pp.383-401
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• 2014

Over the past years, hybrid building systems, consisting of reinforced concrete frames in bottom and steel frames in top are used as a cost-effective alternative to traditional structural steel or reinforced concrete constructions. Dynamic analysis of hybrid structures is usually a complex procedure due to various dynamic characteristics of each part, i.e. stiffness, mass and especially damping. In hybrid structures, one or more transitional stories with composite sections are used for better transition of lateral and gravity forces. The effect of transitional storey has been considered in no one of the studies in the field of hybrid structures damping. In this study, a method has been proposed to determining the equivalent modal damping ratios for hybrid steel-concrete buildings with transitional storey. In the proposed method, hybrid buildings are considered to have three structural systems, reinforced concrete, composite steel and concrete (transitional storey) and steel system. In this method, hybrid buildings are substituted appropriately with 3-DOF system.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 추계 학술논문 발표대회
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• pp.57-60
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• 2008

According to the recent tendency that the buildings in the downtown concerning rising land prices and efficient use of building are gradually Manhattanized mainly the grand scaled residential buildings, structure of the buildings relates to safety and so the very thick mat concrete is selected as the foundation of architectures. Because mat concretes can not be simultaneously pour in a great quantity due to the circumstance at the field, not only the questions on the unification between the concretes pour on the upper layer and the lower layer are presented but also the cracks by the internal force from the difference of hydration exothermic period are occurred because of the time lag. Thus, this study checked the efficiency to apply "The hydration heat controlling method of mass concrete for horizontal partition pouring construction" to the skyscraper sites under construction at Haiundai in Busan. After applying this method, the result of observation that the cracks by hydration heat in all over the placement surface did never be founded. Also, in case of the economic analysis that the hydration heat reduction method using super retarding agent by difference of setting time is approximately 80% cheaper than the hydration heat reduction method by pipe cooling in the construction expenses.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.200-201
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• 2017

Generally, a lot of reinforcements are used in nuclear power plant concrete structures, and it may cause several potential problems when concrete is poured. Because of the congestion caused by hooked bars, embedded materials, and other reinforcements, it is too difficult to pour concrete into structural member joint area. The purpose of this study is to change ACI 349 Code for using the large-size(57mm) and high-strength(Gr.80) headed deformed bars instead of standard hooked bars in nuclear power plant concrete structures in order to solve the congestion problems.