• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.77-78
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• 2023

As large logistics buildings have high floor heights and long spans, these buildings are designed as PC structures, and large cranes are used to lift PC members. PC erection planning can generally cause errors depending on the field engineer's experience. To solve this problem, a basic analysis method is needed to establish a systematic PC member erection plan. Crane work can be minimized if the trajectory is easily and quickly calculated according to the location of the crane and applied to the site. Therefore, the objective of this study is a basic study of crane trajectory distance calculation for sustainable PC members erection of large logistic building. In this study, a crawler crane commonly used for lifting PC members is limited. The trajectory distance for the PC erection plan was automatically calculated using the algorithm.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.92-93
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• 2014

Green Frame is a method for Rahmen structure construction composed of composite PC members. The composite PC members of Green Frame which are based on in-situ production can reduce the construction cost and are more likely to secure quality when compared to production in factories. Previous studies developed forms for in-situ production of Green Frame composite PC members and proposed algorithms to arrange them on site. However, it requires not only their arrangement, but also calculation of an accurate production period to produce the required PC members in a limited space and supply them in a timely manner. In particular, it is necessary to clearly define the properties of detailed processes for in-situ production of PC members and to calculate the time required for respective process. To do so, this study is a basic research on calculating the time for in-situ production using a linear scheduling method.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.176-177
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• 2013

The composite PC rahmen structure, called Green Frame, allows the main structural members such as PC column and beam to be produced on the site, resulting in a reduction of PC member transportation cost and the margin of PC plant (operation cost and profit), making it more economic than the bearing wall structure. To apply the Green Frame to practice, not only installation but also insitu-production process should be considered. Therefore, this study analyse the influence factors on insitu-production and installation schedule of composite precast concrete members. The results shall be used as basic criteria on the planning of insitu-production and installation of Green Frame.

• 국제학술발표논문집
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• The 7th International Conference on Construction Engineering and Project Management Summit Forum on Sustainable Construction and Management
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• pp.263-270
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• 2017

The precast concrete (PC) structure has been preferred for reasons of shortening the construction time and securing the quality and, in particular, it has a cost saving effect in case of long span and heavy loaded structure with high floor height. Most engineers take it for granted to install the plant produced PC members. Researchers in several papers have argued that slander PC members such as columns and girders can be cost-effective if in-situ production is possible, while ensuring quality equal to or better than in-plant production. However, this argument is not officially accepted because objective verification has not been done. Therefore, the purpose of this study is to experimentally conduct in-situ production of PC members to verify the above claim. For this study, a storage building with long span and heavy loaded structure with high floor height was selected as a case study site. For the site, most of the PC members were supplied from the plant, and some of the columns were produced in the site for this study. As a result, it has been confirmed that it has a cost saving effect of 20% while having superior quality to plant-produced PC columns.

• 한국건설관리학회논문집
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• 제13권3호
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• pp.34-42
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• 2012

국내 공동주택의 리모델링 수월성 및 이에 따른 장수명화를 위해 그린 프레임 공법이 개발되었다. 그린 프레임 공법은 합성 프리캐스트 콘크리트 부재를 이용한 라멘구조로 벽식 구조와는 달리 양중 및 설치가 골조공사의 주공정으로 작용한다. 따라서 그린 프레임에 의한 적정 골조공사 공기 산정을 위해서는 체계적인 양중계획이 필요하다. 그러나 양중계획은 그린 프레임을 구성하는 요소인 합성 PC 부재(기둥, 보)의 단위 양중공정에 대한 분석이 선행되어야 한다. 따라서 본 연구는 그린 프레임 합성 PC 부재의 양중공정을 분석하는 것을 목적으로 한다. 이를 위해 합성 PC 기둥과 보의 양중절차와 시간을 도출하고, 그 결과를 사례 프로젝트에 적용하여 기준층의 양중 사이클을 분석한다. 본 연구의 결과는 향후 그린 프레임에 의한 골조공사 양중계획 시 핵심자료로 사용된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.42-43
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• 2019

In-situ production of PC (precast concrete) members can reduce costs by about 14.5% -21.6% compared to in-plant production due to the reduction of transportation costs, factory profits and overhead costs. However, in-situ production of PC members presents a variety of risks, including member production and yard area securing, and lead time for production within the installation period. To solve this, it is necessary be able to analyze and control and monitor the risk factors that influence in-situ production for PC member. The purpose of this study is to develop a dynamic simulation model for in-situ production and erection integrated management for PC members. For this study, risk factor identification, causal loop diagram, and dynamic simulation model construction were performed sequentially. The results of this study will be used as a basis for developing a risk management model for PC in-situ production.

• Smart Structures and Systems
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• 제20권4호
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• pp.397-413
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• 2017

Precast concrete (PC) members are currently being employed for general construction or partial replacement to reduce construction period. As assembly work in PC construction requires connecting PC members accurately, measuring the 6-DOF (degree of freedom) relative displacement is essential. Multiple planar markers and camera-based displacement measurement systems can monitor the 6-DOF relative displacement of PC members. Conventional methods, such as direct linear transformation (DLT) for homography estimation, which are applied to calculate the 6-DOF relative displacement between the camera and marker, have several major problems. One of the problems is that when the marker is partially hidden, the DLT method cannot be applied to calculate the 6-DOF relative displacement. In addition, when the images of markers are blurred, error increases with the DLT method which is employed for its estimation. To solve these problems, a hybrid method, which combines the advantages of the DLT and MCL (Monte Carlo localization) methods, is proposed. The method evaluates the 6-DOF relative displacement more accurately compared to when either the DLT or MCL is used alone. Each subsystem captures an image of a marker and extracts its subpixel coordinates, and then the data are transferred to a main system via a wireless communication network. In the main system, the data from each subsystem are used for 3D visualization. Thereafter, the real-time movements of the PC members are displayed on a tablet PC. To prove the feasibility, the hybrid method is compared with the DLT method and MCL in real experiments.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.253-254
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• 2023

The production plan of Precast Concrete members is closely related to the assembly plan of Precast Concrete members, and is an important management factor for the process planning of Precast Concrete construction. This may cause a delay in the construction period due to manufacturing errors occurring in the production process of members and transportation errors according to the production sequence. Therefore, it is necessary to have an efficient production plan for Precast Concrete members that can produce the necessary quantity from the point of assembly of the members and supply them in a timely manner. This study is a basic study for establishing a production plan for Precast Concrete members, and the purpose of the study is to examine the factors that affect the establishment of a production plan for Precast Concrete members. In this study, the influencing factors according to the production method and conditions when establishing a production plan for Precast Concrete members were considered. In the future, correlation analysis among influencing factors will be carried out, and it is expected that it will be used as basic data for schedule management of Precast Concrete construction and derivation of construction period calculation standards.

• Structural Engineering and Mechanics
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• 제76권1호
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• pp.67-81
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• 2020

Pretensioned concrete (PC) is widely used in contemporary construction. Bond of prestressing strand is significant for composite-action between the strand and concrete in the transfer and flexural-bond zones of PC members. This study develops a new methodology for quantifying the bond of 18-mm prestressing strand in PC members based on results of a pullout test, the Standard Test for Strand Bond (STSB). The experimental program includes: (a) twenty-four pretensioned concrete beams, using a wide range of concrete compressive strength; and (b) twelve untensioned pullout specimens. By testing beams, the transfer length, flexural-bond length, and development length were all measured. In the STSB, the pullout forces for the strands were measured. Experimental results indicate a significant relationship between the bond of prestressing strand to the code-established design parameters, such as transfer length and development length. However, the code-predictions can be unconservative for the prestressing strands having a low STSB pullout force. Three simplified bond equations are proposed for the design applications of PC members.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.29-30
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• 2011

A Green Frame is a composite Rahmen precast concrete structure that utilizes the advantages of the steel frame and the reinforced concrete. Compared to bearing wall structure, the precast concrete structure may raise construction cost If the precast concrete members are produced in plant. Thus, if the precast concrete members can be produced in site, the cost-effectiveness and quality shall be increased. Various site conditions must be considered and reviewed to ensure a space for the in-situ production. Therefore, this study focuses on the basic study on the arrangement of in-situ production module of composite precast concrete members.