• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.212-213
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• 2013

The constructability of Formwork has a importantly influence on the duration and cost in a construction project. However, the existing studies on the formwork are mainly focused on a method of construction. Although a layout planning of forms, especially, is an important factors affecting the constructability and cost, it is done by engineers empirically and intuitionally after completion of structure design. Therefore this study suggest a decision support model for optimal formwork layout model based on the rearrangement of structural members by using Genetic Algorithm to improve constructability of formwork.

• 한국안전학회지
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• 제26권3호
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• pp.59-62
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• 2011

Among the accidents and failures that occur during concrete construction, many are formwork failures which usually happen when concrete is being placed. A system of formwork filled with wet concrete has its weight at the top and is not basically a stable structure. Slab formwork consists of sheathing, stringer, hanger and shore. There are several types of adjustable shores. In construction site, pipe supports are usually used as a shore of slab formwork. In this study, pipe support systems with/without horizontal connector were measured by buckling test. Buckling load of respective pipe support system was analyzed by structural analysis program(MIDAS). Buckling load of pipe support with/without horizontal connector was got by test and structural analysis. According to these results, we know that horizontal connector made pipe support system very safe. Buckling load of pipe support with horizontal connector is 56% higher than that without horizontal connector. So horizontal connector is important in slab formwork systems. Finally, the present study results will be used to design slab formwork system safely in the construction sites.

• 한국안전학회지
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• 제23권4호
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• pp.67-71
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• 2008

Formwork is a temporary structure that supports its weight and that of fresh concrete as well as construction live loads. Slab formwork consists of sheathing, stringer, hanger and shore. In construction site, pipe supports are usually used as shores which are consisted of the slab formwork. In this study, compressive strength of 80 pipe supports was measured by knife edge test and plate test. Buckling load of pipe supports was analyzed by structural analysis program(MlDAS). Theoretical buckling load with/without initial deformation was got by theoretical analysis. According to these results, buckling load which was analyzed by structural analysis program(MlDAS) was larger than compressive strength of knife edge test and plate test. Theoretical buckling load without initial deformation was larger than compressive strength of knife edge test and plate test. But Theoretical buckling load with initial deformation was lower than compressive strength of knife edge test and plate test. Initial deformation equation for test method according to the pipe support length was suggested. Therefore, the present study results will be used to design the slab formwork safely.

• 한국공간구조학회논문집
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• 제17권4호
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• pp.167-174
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• 2017

The F3D(Free-Form Formwork 3D Printer) technology that manufactures EPS(Expanded Polystyrene) formworks for irregular-shaped concrete structures by 3D printers was developed to reduce the cost and time. Because of weak strength and low elastic modulus of the EPS, structural performance including lateral pressure by fresh concrete of the formwork that consisted of EPS should be investigated. In order to calculate lateral pressures acting on formwork, several variables including sizes, shapes of formwork, tangential force(fricition) between fresh concrete and formwork, and material properties of fresh concrete should be considered. However, current regulations have not considered the properties of concrete, only focused on vertical formwork. Galleo introduced 3-dimensional finite element analysis models to calculate lateral pressure on formwork. Thus, proposed finite element analysis model based on previous studies were verified for vertical formwork and irregular-shaped formwork. The test results were compared with those by FEM analysis. As a result, the test agrees well with the analysis.

• Structural Engineering and Mechanics
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• 제24권5호
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• pp.561-584
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• 2006

The paper presents results of parametric studies, and an overall approach for the design of a modular bridge system which incorporates a steel-reinforcement free concrete slab cast on top of carbon FRP stiffened deck panels which act as both structural formwork and flexural reinforcement, spanning between hollow box type FRP girders. Results of the parametric studies are highlighted to elucidate important relationships between critical configurational parameters and empirical equations based on numerical studies are presented. Results are discussed at the level of the individual deck and girder components, and as a slab-on-girder bridge system. An overall design methodology for the components and bridge system including critical performance checks is also presented.

• International Journal of Concrete Structures and Materials
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• 제10권sup3호
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• pp.1-17
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• 2016

Recently, advanced transit systems are being constructed to reduce traffic congestions in metropolitan areas. For these projects, curved bridges with various curvatures are required. Many curved bridges in the past were constructed using aesthetically unpleasant straight beams with curved slabs or expensive curved steel box girders with curved slabs. Therefore, many recent studies have been performed to develop less expensive and very safe precast prestressed concrete (PSC) curved girder. One method of reducing the construction cost of a PSC curved girder is to use a reusable formwork that can easily be adjusted to change the curvature and length of a girder. A reusable and curvature/dimension adjustable formwork called Multi-tasking formwork is developed for constructing efficient precast PSC curved girders. With the Multi-tasking formwork, two 40 m precast PSC box girders with different curvatures were constructed to build a two-girder curved bridge for a static flexural test to evaluate its safety and serviceability performance. The static flexural test results showed that the initial cracking load was 1400 kN, exceeding the design cracking load of 450 kN. Also, the code allowed deflection of 50 mm occurred at a load of 1800 kN, verifying the safety and serviceability of the precast PSC curved bridge constructed using the multi-tasking formwork.

• 대한건축학회논문집:구조계
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• 제35권7호
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• pp.171-178
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• 2019

Auto Climbing Formwork System (ACS) for construction of high-rise building is a construction method for automatically lifting the formwork system supported by the anchor on the pre-constructed concrete wall. It has excellent construction speed and quality, but it has the possibility of structural failure depending on the quality of concrete and also has low economical efficiency due to the use of foreign technology. In order to overcome these problems, this study conducted an optimum design for the development of a new concept of Corner Supported Auto Climbing System (CS-ACS) in conjunction with the development of corner steel-reinforced concrete core wall system. For the design the formwork system, the basic module and structural member compositions were planned, and the structural analysis program was used to analyze the optimum member's cross section and spacing. As a result, the horizontal displacement and the stress of the horizontal members were influenced by the spacing more than the cross-section of the member. On the other hand, vertical members did not affect the displacement and stress of the formwork system. The form tie was very effective in controlling the displacement when adjusting the spacing of the horizontal members, but when the spacing of the form tie is more than 1,500mm, it is analyzed that form tie is yielding in basic module. When the span of the formwork system is more than 30m, it is analyzed that the basic module needs to be changed because of the increase of overall displacement.

• 한국구조물진단유지관리공학회 논문집
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• 제27권5호
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• pp.130-138
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• 2023

이 연구에서는 강재 영구거푸집 와이드 보를 대상으로 시공하중에 대한 실험적‧해석적 연구를 수행하였다. 측면강판의 리브 간격과 고정철물의 깊이를 변수 총 4개의 실험체를 제작하여 실험을 수행하였으며, 변수별 실험체의 구조거동 차이를 상세히 분석하였다. 또한, 실험결과를 기반으로 강재 영구거푸집 와이드 보의 유한요소해석 모델을 제안하였다. 검증된 해석모델을 활용하여 하부 및 측면강판의 리브 간격, 고정철물 간격, 고정철물 깊이 및 두께를 변수로 해석적 연구를 수행하였으며, 이를 통해 최적화된 상세를 도출하였다. 더 나아가 다양한 상세를 가지는 강재 영구거푸집 와이드 보의 변형량을 간단하게 예측할 수 있는 인공신경망 예측모델을 제안하였다.

• 한국안전학회지
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• 제14권4호
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• pp.142-147
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• 1999

Formwork is a temporary structure that supports its own weight and that of the freshly placed concrete as well as construction live loads including materials, equipments, and workmen. In designing and building formwork, the contractor should plan for economical construction without sacrificing quality or safety. But these temporary structures sometimes collapse during the concrete placing. Among the accidents and failures that occur during concrete construction, many are formwork failures, which usually happen at the time concrete is being placed. Generally some unexpected events cause one member to give way, then others become overloaded or misaligned and the whole formwork structure collapses. In this study, formwork failure events from 1994 to 1997 are analyzed using the structural analysis program. So the causes of the respective formwork failure are explored. Therefore, the present study provides a firm base to design the temporary structures such as formwork.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2007년도 추계 학술논문 발표대회
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• pp.115-118
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• 2007

A tall building construction is needed to reduce the construction duration for project profitability. Reducing the cycle time of typical floor in the structural frame work which have the largest duration in the whole construction, greatly affects construction duration. Nowadays, some projects are accomplished in the 3 day cycle. In order to accomplish efficiently 3 day cycle, productivity information of similar projects is supported. Therefore, this study proposed labor productivity and application by slab formwork to construct by the 3 day cycle. In order to perform an analysis, we selected 3 cases and analyzed the labor productivity on the basis of the amount of slab forms, labors, and durations. Then, we performed the questionnaire to analyze the application by formwork of tall building construction engineers. This study will contribute to establish a reasonable scheduling in structural frame work of a new similar project.