• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.49-52
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• 2007

Recently, as architectural concrete structures become high-rise and megastructured, concrete become high-strengthened and, by ensuring products of more stability, air compression and rationalization of construction are required. In general, product management test of precast concrete member, specimen for management cured in the same condition with precast concrete member is substitutively used for strength test. However, large cross-sectional precast concrete members such as columns show large temperature increase in manufacturing process not only by external heating but also by concrete itself's hydration heating. Therefore, it is expected that specimen for management to predict strength and compression strength of precast concrete member shows different temperature history and strength characteristics. Concerning this, in order to suggest temperature history and strength characteristics of high strength mass concrete suitable for precast concrete application, this study comprises the inclusive investigations on the relations between management specimen with similar temperature history and core strength, and the strength characteristics per member cross-section dimensional value and per water-bonding material ratio value.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.73-76
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• 2006

The shape and dimension of precast concrete structure used in habor construction(caisson, block, etc.) are considered productive facility abilities, demanded minimum dimension in work of each member, the relation between the depth of water and a location of leaving, work conditions of towing and leaving, after leaving, differential settlement, etc. As this study examined friction resistance effect of financially designed precast concrete structure formed convex in bottom and stone mound.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1326-1331
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• 2006

The precast concrete deck is one of suitable solutions for replacement and new construction in urban area. However, the precast concrete deck could be a weak point of the steel plate girder bridges structurally due to the connections between precast panels in the longitudinal direction. Thereafter, it is necessary for improvement of durability and load carrying capacity to introduce the prestress force in the longitudinal direction Some cracks of connections at the precast concrete deck may be occurred due to live loads, the difference of temperature and long-term effects. The shrinkage and creep of concrete may significantly affect long-term behaviors which occur tensile stresses at the precast concrete deck of steel plate girder bridges. In this study, the time-dependant analysis program has been developed to determine the initial prestress force in the longitudinal direction considering loss of stress at the precast concrete deck. Also it has been estimated the initial prestress force by construction stages and shapes of girder.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1992년도 봄 학술발표회 논문집
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• pp.99-104
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• 1992

There is a limit manufacturing precast products for the construction industry using conventional cement concrete and precast iron due to many reasons. Therefore, precast product technologies using polymer concrete are widely developed across the world because using polymer concrete can be over come this limitation. This study reviewed and analyzed the trends of development and practical usages of ploymer concrete precast products in foreign countries based on selected literatures. It was observed that polymer concrete precast products have been widely used as utility structures wall and slab members. decoration products, traffic products, hydraulic structures and industry equipments.

• 한국건축시공학회지
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• 제5권1호
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• pp.89-96
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• 2005

The increase of hish-rise residential-commercial buildings is required to cut down a term of works and the cost of construction. Reinforced concrete structures and steel framed reinforcement concrete that are commonly used have the difficulty in reducing them. Therefore, the purpose of this study is to propose a new precast concrete complex system and to analyze its economical feasibility. The economic analysis is performed through comparing the cost of a high-rise reinforced building that was already constructed with that of the new proposed precast concrete system, which is limited to structural frame work of typical floors. This study shows that the proposed precast concrete complex system is economical. Further research should be directed at including the influence of a term of works.

• 한국건축시공학회지
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• 제11권5호
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• pp.501-514
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• 2011

Recently, there have been many cases in which the difficulty of repair and replacement of principal elements in the bearing wall structure for apartment buildings, which is a major part of apartment buildings in Korea, has led to the reconstruction of buildings rather than their remodeling. To address this problem, the Korea government now allows a floor area ratio of up to 20 %, and has relaxed the building height limits to encourage the use of a rahmen structure instead of a bearing wall structure. However, since reinforced concrete rahmen structures have many problems, including higher floor height and greater construction cost, a great deal of research into rahmen composite precast concrete structures have been conducted. Green Frame, one of the developed prototypes, is expected to provide economic benefits through in-situ production for precast concrete column and beam. For in-situ production of composite precast concrete members, a detailed plan for production, curing, and installation is needed. However, it needs to be confirmed that the space is sufficient to produce the precast concrete members on-site before planning those activities. Therefore, this study proposes in-situ production analysis of composite precast concrete members of Green Frame with the evaluation of structural safety and available area on the parking structure. The result of this study shows that the in-situ production of precast concrete members is possible through a case study.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.743-748
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• 1997

In this paper, a new type of precast perforated concrete block is presented to be used in the construction of a step seawall. The overtopping rate of the perforated step seawall is lower than that of the traditional non-perforated step seawall. In construction stage, the cost of total construction of the perforated block is cheaper than that of traditional block. The new type of perforated block may be used as an alternative for shore protection facility.

• KIEAE Journal
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• 제10권1호
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• pp.25-31
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• 2010

An experimental investigation of composite beams composed of wide flange steel and precast concrete is presented. The bottom flange of the steel section is encased in precast concrete. The composite beams tested in this study were designed to reduce the depth of the slab and beam. The slabs are constructed on top of the edges of the Structural Composite Hybrid System, instead of on top of the steel flange, decreasing the depth of the beams. When concrete is cast on the metal deck plate located on the edges of the precast concrete, the weight of the concrete slabs and other construction loads must be supported by the contacts between the steel and the precast concrete. This interface must not exhibit bearing failures, shear failures, and failures caused by torque due to the loading of the precast concrete. When the contact area between the concrete and the bottom flange of the steel beam is small, these failures of the concrete are likely and must be prevented. The premature failure of precast concrete must not also be present when the weight of the concrete slabs and other construction loads is loaded. This paper presents a load carrying capacity of Structural Composite Hybrid System in order to observe the failure mode. The symmetrically distributed loading that caused the failure of the composite beam was found. The paper also provides design recommendations of such type of composite structure.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.11-12
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• 2015

Green Frame is a Rahmen structure made of composite precast concrete members. According to the concrete design code, a lower rebar of precast concrete girder, should be extended to the inner precast concrete column. However, such extension of lower rebar may sharply reduce its constructability. To satisfy the criteria, the connection and anchorage of beam rebar should be taken into consideration, yet it is difficult to use lapping as it is not easy to ensure enough space when Green Frame method is adopted. To solve this, a new method of lower rebar connection and anchorage was developed, and this study is intended to review economic feasibility prior to applying the method developed onto sites. The study result can be used as basic data for selection of the optimal joint and anchorage method for lower rebar of the green frame construction.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.19-20
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• 2013

Green Frame is a column-beam system constructed by composite precast column and beam connected by embedded steel of their. From when the precast concrete beam of Green Frame is installed, until the concrete of slab and connection joint is cured, the self load of beam shall be supported by the embedded steel of it. Therefore, the concrete of beam could be separated from the embedded steel if the shear connector of beam of Green Frame is designed by the code on Structural standard. So, this study suggest an equation for the shear connection of composite precast concrete beams of Green Frame. The result of this study will be used as the main equation of the calculation model for shear connectors of composite precast concrete beams.