• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
• /
• pp.903-910
• /
• 2000

Because the construction type SFRB is completely different in comparison with that of RC apartment the construction and work process, which are currently used, have to be changed. The main purpose of study is to analyze the difficulties of this construction and to apply the technology for other construction area. In this study, it is investigated to the problems of construction for SFRB and the construction method of PC panel fabricated on SFRB in Yongin goosng. Later, it is estimated prefabricated method had an great effect on PC panel System as lower cost and shorter schedule in SFRB. The Precast concrete framed System has many merit than the reinforced concrete structures system at constructability, structural safety and quality, therefore, it will be widely applied at parking structure in the future.

• 한국건축시공학회지
• /
• 제10권4호
• /
• pp.83-93
• /
• 2010

건설프로젝트가 점차 복잡화, 대형화 되어감에 따라 건설공사에서의 위험요소와 불확실성이 증가하고 있으며, 프로젝트 수행과정에서 발생하는 불확실한 요인을 사전에 파악하여 대응하는 것은 프로젝트의 승패를 좌우할 수 있다. 따라서 본 연구의 목적은 토공사, 기초공사, 철근콘크리트 공사에서의 제약조건과 위험요소를 파악함과 동시에 시공 계획수립의 실태를 분석함으로써 위험을 저감할 수 있는 방안을 제시하는 것이다. 이러한 연구목적을 달성하기 위해 위험분류체계에 관한 기존연구를 고찰하였으며, 건설현장에 근무하는 기사를 대상으로 인터뷰조사를 실시하여 안전 관리의 문제점을 구체화하기 위해 실증적인 현장사례연구를 수행하였다. 주요 연구내용은 건설현장의 특수상황 및 주요 공법의 적용실태, 제약조건과 위험요소의 인과관계이며, 위험을 저감하기 위한 중점관리 방안을 제시하였다.

• 한국건축시공학회지
• /
• 제14권5호
• /
• pp.487-495
• /
• 2014

골조공사는 프로젝트의 전체 공사비 및 공사기간에서 차지하는 비율에 매우 높으며, 대형 프로젝트에서 골조공사 공기단축은 프로젝트의 성패를 결정하는 중요한 요소이다. 이에 공기단축을 위한 새로운 공법에 대한 연구가 지속적으로 이루어져 오고 있다. H형강 대신 앵글을 사용하는 PSRC 합성기둥은 기존의 SRC 기둥에 비해 높은 휨강도 및 연성도를 가지며 현장에서의 철근작업을 생략할 수 있다는 장점이 있으나, 여전히 거푸집작업이 필요하다는 한계점이 있다. 본 연구는 기존의 PSRC 기둥 공법을 개선하여 영구거푸집까지 선조립하는 Form-LPSRC 기둥 공법을 개발하는 것을 목적으로 한다. Mock-up test를 통해 발생 가능한 문제점을 사전에 검토함과 동시에 현장 적용을 통해 해당 공법의 적용효과를 분석하였으며, 기존 SRC 기둥에 공기, 원가, 품질, 안전, 환경 측면에서 우수한 것으로 나타났다.

• 한국농공학회지
• /
• 제30권2호
• /
• pp.67-81
• /
• 1988

The purpose of the present study is to set up an efficient optimum design method for the large-scale reinforced concrete cylindrical shell structures like intake tower of reservoir and to establish a solid foundation for the automatic optimum structural design combined with finite element analysis. The major design variables are the dimensions and steel areas of each member of the structures. The construction cost which is composed of the concrete, steel, and form work costs, respectively, is taken as the objective function. The constraint equations for the design of intake-tower are derived on the basis of the working stress design method. The corresponding design guides including the standard specification for concrete structures have been also employed in deraving the constraint conditions. The present nonlinear optimization problem is solved by SUMT method. The reinforced concrete intake-tower is decomposed into three major substructures. The optimization is then conducted for both the whole structure and the substructures. The following conclusions can be drawn from the present study. 1. The basis of automatic optimum design of reinforced concrete cylindrical shell structures which is combined with finite element analysis was established. 2. The efficient optimization algorithms which can execute the automatic optimum desigh of reinforced concrete intake-tower based on the working stress design method were developed. 3. Since the objective function and design variables were converged to their optimum values within the first or second iteration, the optImization algorithms developed in this study seem to be efficient and stable. 4. The difference in construction cost between the optimum designs with the substructures and with the entire structure was found to be small and thus the optimum design with the substructures,rnay conveniently be used in practical design. 5. The major active constraints of each structural member were found to be the tensile stress insteel for salb, the minimum lonitudinal steel ratio constraints for tower body and the shearing stress in concrete, tensile stress in steel and maximum eccentricityconstraints for footing, respectively. 6. The computer program develope in the present study can be effectively used even by an unexperienced designer for the optimum design of reinforced concrete intake-tower.

• 한국농공학회지
• /
• 제30권3호
• /
• pp.82-94
• /
• 1988

A growing attention has been paid to the optimum design of structures in recent years. Most studies on the optimum design of reinforced concrete structures has been mainly focussed to the design of structural members such as beams, slabs and columns, and there exist few studies that deal with the optimum design of large-scale concrete shell structures. The purpose of the present investigation is, therefore, to set up an efficient optimum design method for the large-scale reinforced concrete cylindrical shell structures like intake tower of reservoir. The major design variables are the dimensions and steel areas of each member of structures. The construction cost which is compo8ed of the concrete, steel, and form work costs, respectively, is taken as the objective function. The constraint equations for the design of intake-tower are derived on the basis of strength design method. The results obtained are summarized as follows 1. The efficient optimlzation algorithrns which can execute the automatic optimum design of reinforced concrete intake tower based on the strength design method were developed. 2. Since the objective function and design variables were converged to their optimum values within the first or second iteration, the optimization algorithms developed in this study seem to be efficient and stable. 3. When using the strength design method, the construction cost could be saved about 9% compared with working stress design method. Therefore, the reliability of algorithm was proved. 4. The difference in construction cost between the optimum designs with substructures and with entire structure was found to be small and thus the optimum design with substructures may conveniently be used in practical design. 5. The major active constraints of each structural member were found to be the 'bending moment constraint for slab, the minimum longitudinal steel ratio constraint for tower body and the shearing force, bending moment and maximum eccentricity constraints for footing, respectively. 6. The computer program developed in the present study can be effectively used even by an uneiperienced designer for the optimum design of reinforced concrete intake-tower on the basis of strength design method.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
• /
• pp.817-822
• /
• 2002

The problem of the crack which occures from the reinforced concrete structure could be caused by the complexed factors. When the crack happen, it caused fatal blemish to manage and maintain the structure such as structural problem, licking, spalling, viewing Even though they study and work hard to solve this kind of problem in the world, there are no countermeasure for perfect prevention of crack. After the crack checked out, a method of repair-reinforcement has been studied and operated actively, Generally, occurance of the crack in the concrete structure could be taken as granted, no need to mention the damage from the crack, domestic construction try to hide it rather than repair basically, In many cases the construction amount for repairing the crack has to be made in the construction area and the amount is very expensive. To save the repaing fee, companys repair it under the meeting of their desire. it can be expected for the effection of the construction. For this reason, we compare a new injection method to solve the demerits of the present method, to save and use the merit of the present method.

• 한국건축시공학회지
• /
• 제14권4호
• /
• pp.314-321
• /
• 2014

특수 플랜트 건설은 타 건설사업보다 체계적인 원가 및 공정관리가 요구되지만 이를 위하 반드시 필요한 현장 생산성을 구체적으로 분석한 연구는 이루어지지 않고 있다. 본 연구에서는 국내에서 건설중인 특수 플랜트 현장의 철근콘크리트공종을 형틀, 철근, 콘크리트로 나누어 생산성을 측정하고 생산성에 영향을 미치는 요인을 분석하였다. 생산성 측정결과 형틀공종 $0.54(m^2/man{\cdot}time)$, 철근공종 $0.06(ton/man{\cdot}day)$, 콘크리트공종 $1.98(m^3/man{\cdot}time)$로 나타났다. 영향요인으로는 형틀공종은 요일과 야간적업 유무, 철근공종은 야간잡업 유무, 콘크리트공종은 야간작업 유무와 콘크리트 물량이 통계적으로 유의게 영향을 미치는 것으로 분석되었다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2003년도 학술.기술논문발표회
• /
• pp.147-152
• /
• 2003

Passage of time axial shortening in the cores and columns of tall concrete buildings requires special attention to ensure proper behavior for strength of the structure and the nonstructural element. The effects of column shortening, both elastic and inelastic, take on added significance and need special consideration in design and construction with increased height of structures. In this paper, the compensation method of column shortening for reinforced concrete structure are introduced. It could be concluded that the survey is a significant factor for the compensation instance of column shortening.

• Advances in concrete construction
• /
• 제8권1호
• /
• pp.9-19
• /
• 2019

This paper describes an experimental investigation on hybrid fiber reinforced concrete (HYFRC) beams. And the main aim of this present paper is to examine the dynamic characteristics and damage evaluation of undamaged and damaged HYFRC beams under free-free constraints. In this experimental work, totally four RC beams were cast and analyzed in order to evaluate the dynamic behavior as well as static load behavior of HYFRCs. Hybrid fiber reinforced concrete beams have been cast by incorporating two different fibers such as steel and polypropylene (PP). Damage of HYFRC beams was obtained by cracking of concrete for one of the beams in each set under four-point bending tests with different percentage variation of damage levels as 50%, 70% and 90% of maximum ultimate load. And the main dynamic characteristics such as damping, fundamental natural frequencies, mode shapes and frequency response function at each and every damage level has been assessed by means of non-destructive technique (NDT) with hammer excitation. The fundamental natural frequency and damping values obtained through dynamic tests for HYFRC beams were compared with control (reference) RC beam at each level of damage which has been acquired through static tests. The static experimental test results emphasize that the HYFRC beam has attained higher ultimate load as compared with control reinforced concrete beam.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
• /
• pp.357-360
• /
• 2004

Estimation of deformation capacity of non-flexural reinforced concrete members is proposed using basic concepts of limit analysis and the virtual work method. This new approach starts with construction of admissible stress field as for an equilibrium set. Failure mechanisms compatible with admissible stress fields are postulated as for displacement set. It is assumed that the ultimate deformations as result of failure mechanisms are controlled by ultimate strain of concrete in compression. The derived formula for deformability of deep beams in shear shows reasonable range of ultimate displacement.