• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.387-391
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• 2007

A proper selection of formwork greatly affects project success in tall building construction. The tall building construction, however, has not been selected properly using the characteristics by formwork and demands the comprehensive consideration of cost, duration, quality, safety, and environment. Therefore, this study compares and analyzes the application by formwork of five aspects. In order to perform an analysis, the questionnaire was performed to research the priority order of management as determining formwork and application by formwork of tall building construction engineers. This study is expected to help reasonable selection of formwork.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.788-793
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• 2009

Constructing substructures by using Top-Down or Downward method needs an efficient formwork system because of difficulties in supporting concrete slabs from the bottom while excavation is in process. Existing underground formwork systems can be classified by three types: graded ground supported type (Slab On Grade, Beam On Grade), suspension type (Non Supporting Top Down Method), and bracket supported type (Bracket Supported R/C Downward). Each method has its own advantages and limits. Application of a specific formwork system for a given construction site is determined by various conditions and affect construction time and cost. This paper presents a newly developed underground non-supporting formwork system, which combines the advantages of a suspension type and a bracket supported type while it overcomes limits of two types. The developed system has a moving formwork which is supported by suspension cables hanging from the bracket placed at the top of pre-installed substructure columns. Then, the moving formwork is repeatedly lowered down for the next floor below to support concrete slab during curing. The details of this bracket and cable supported system have been investigated for the improvement of easiness in construction.

• Steel and Composite Structures
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• v.50 no.6
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• pp.689-703
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• 2024

Construction of high-rise structures, formwork systems that can be installed quickly, resistant to external loads, can be used more than once, have become a necessity. Timber and composite timber materials are preferred in the formation of such formwork systems due to their durability, ease of assembly, light weight and easy to use more than one time. Formwork beams are the most commonly used structural component in the formation of such formwork systems, and these beams can be damaged for different reasons during their lifetime. In this study, H20 top P type timber formwork beams with 1800 and 2450 mm length which is among the products of DOKA(c) company is damaged under the effect of static loading up to a high load level of 85% of the maximum ultimate capacity and after being retrofitted using anchored CFRP strips, performance and behavior of the beams under the influence of various loading types such as static, fatigue and impact are investigated experimentally. Two different lengths of retrofitted timber formwork beams were tested by applying monotonic static, fatigue and impact loading and comments were made about the effects of the retrofit method on performance under different loading types.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.309-312
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• 2006

An experimental study for bond slip behavior of concrete and a FRP plank was used as the both formwork and the tensile reinforcement for a concrete structural member is described. For the FRP plank and the concrete to act as a composite structural member a satisfactory bond at the interface between the smooth surface of the FRP and the concrete must be developed. This study focuses on investigation of the bond slip behavior of sand coated interface between FRP and cast-in-place concrete experimentally.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.2
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• pp.141-148
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• 2003

Concrete surface is a part that resists chiefly to carbonation by carbonic acid gas, affluence of rainwater and air, deterioration by freezing thawing, salt damage by seawater, and other chemical erosion etc. Therefore, this research analyzed physical characteristic and durable characteristic of concrete eliminated glut water and bubble of concrete surface using CON-SILK that is permeated with dehydration. As a research result, concrete using CON-SILK was improved, in comparison with concrete using general formwork, in physical performance and durability of concrete, as surface hardness, carbonation resistivity, and salt content permeation resistivity etc. Therefore, we could know that it is effective to use CON-SILK in performance elevation of concrete surface.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.121-127
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• 2010

An experimental study of composite beam with perforated fiber reinforced polymer(FRP) plank as a permanent formwork and the tensile reinforcement was performed. A combined formwork and reinforcement system can facilitate rapid construction of concrete members since no conventional formwork is needed, which requires time consuming assembly and dismantling. In order for a smooth FRP plank to act compositely with the concrete, the surface of the FRP needs to be treated to increase its bond properties. Aggregates were bonded to the FRP plank using a commercially available epoxy and perforated web of plank. No additional flexural or shear reinforcement was provided in the beams. For comparison, two control specimens were tested. One control had no perforated hole in the web of FRP plank and the other had internal steel reinforcing bars instead of the FRP plank. The beams were loaded by central patch load to their ultimate capacity. This study demonstrates that the perforated FRP plank has the potential to serve as a permanent formwork and reinforcing for concrete beam.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.60-67
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• 2021

In lately, it's been developed and used a system of using deck plates as formwork in order to solve various problems caused by conventional formwork system. This system is more economical and has higher constructability than the conventional system by permanently embedding most of deck plates into the members. However, for this kind of embedded deck plates formwork system, it's been reported that it is difficult to verify filling of concrete in members like beams with narrow width and complicated rebar arrangement. In addtion, there are several problems such as corrosion of deck plates in terms of constructability and maintenance. Therefore, in this study, it is attempted to develop a removal-deck plate formwork system for beams by removing deck plates after concrete curing. The system consists of a deck plate module that acts as form, a frame preventing deformation by concrete lateral pressure, stirrup frame, and connector that combines these. As a result of this research, it is verified that it has higher constructability, efficiently prevents deformation caused by concrete lateral pressure and could be easily removed in the developed formwork system.

• Korean Journal of Construction Engineering and Management
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• v.19 no.6
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• pp.3-13
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• 2018

The formwork cost amounts for a significant proportion of project construction costs. It costs 10-15% of the total construction cost and 30-40% of the frame structure construction cost. In addition, the formwork collapse accidents are frequently causing deaths in the construction industry, and thus, is known to be of relatively high degree of risk. As so, the accuracy of structural calculation and quantity take-off when planning the formwork in a construction project are a very important matter. Accordingly, this study develops a BIM based formwork design prototype, that enables the construction manager to optimize the design through applying the proposed new IFC entities associated with the formwork design. The approach proposed in this study is expected to support the construction manager with accurate quantity calculation and rapid planning and construction. Since this study considered specific small-scale buildings using Euro-form and show the possibility of utilizing BIM entities in the formwork design process, further research is recommended towards the limitations in applying the system to other types of formworks.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.1
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• pp.65-72
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• 2008

The use of hybrid FRP-concrete structures with a dual purpose of both permanent formwork and reinforcement, has been considered in some studies recently. For the FRP plank and the concrete to act as a composite structural member a satisfactory bond at the interface between the smooth surface of the pultruded plank and the cast-in-place concrete must be developed. Sand was bonded to the pultruded FRP plank using a commercially available epoxy system. In applying general analysis techniques to evaluate the performance of composite structures with FRP stay-in-place forming, it is essential that characteristics of the bond stress-slip relation be identified. In this study I would like to propose a simplified bilinear bond stress-slip model for FRP composite structures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.92-103
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• 2015

Development of new concrete bridge deck system with FRP plank using as a permanent formwork and the main tensile reinforcement recently has been actively conducted. Concurrent use as a reinforcing material and a permanent formwork, it is possible to reduce the construction time and construction costs than the usual concrete slab. In this study, an experiment was carried out for the bond stress between cast-in-place concrete and the type of FRP plank using as a permanent formwork. The interfacial fracture energy that can be one of the most important parameters were evaluated for adhesion performance and bond stress to know the characteristics of the failure mechanism of the adhesion surface. Interfacial fracture energy of normal concrete is 0.24kN/m of GF11 case, in the case of GF21, 0.43kN/m appears, in the case of CF11 and GF31, 0.44kN/m and 0.46kN/m respectively it appeared. In case of RFCON, 0.52kN/m appears from GF12, the CF12 and GF22, 0.51kN/m and 0.36kN/m appeared each case.