• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.3
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• pp.16-23
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• 2016

DFRCC (ductile fiber reinforced cementitious composites), which are a significantly improved ductile material compared to conventional concrete, were evaluated as a new construction material with a high potential applications to concrete structures for a range of purposes. In this study, experiments on the failure behavior of composite beams with a DFRCC and FRP (fiber reinforced polymer) plank with a rib used as permanent formwork and tensile reinforcement were carried out. A normal concrete and a fiber reinforced concrete with PVA series of RF4000 and the PP series of PP-macro were used for comparison, and each RF4000+RSC15 and PP-macro+RSC15 was tested by producing composite beams. The experimental results of the FRP plank without a sand coating showed that sliding failure mode between the FRP plank and concrete started from a flexural crack at the beam center; therefore it is necessary for the FRP plank to be coated with sand and the effect of the fiber to failure mode did not appear to be huge. The experiment of the FRP plank with a sand coating showed that both 1200mm and 2000mm allowed sufficient bonding between the concrete and FRP plank. The maximum load of the fiber reinforced concrete was higher than that of normal concrete and the case which a series of PP fiber was mixed showed the highest value. The crack latency caused by the fibers led to composite action with a FRP rib.

• Journal of the Korea Institute of Building Construction
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• v.18 no.1
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• pp.89-98
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• 2018

Recently, the importance of the construction technology of the free-formed buildings is becoming more significant, as the interest and demand for the free-formed buildings are increasing. However, it takes much time and cost during the construction of free-formed buildings because the current construction technique of freeform concrete segments is manufactured by a formwork. Therefore, in this study, we suggested a new manufacturing process based on the LOM-type 3D printer for freeform concrete segments that can shorten construction time and reduce cost when constructing freeform concrete segments, and we also verified the feasibility of production process through mock-up test. The result shows that the suggested process shortened 47.8% of production time and saved 56.2% of cost compared to the existing steel formwork method. In conclusion, it is expected that the production method of freeform concrete segments using 3D printer will contribute to the improvement of productivity of freeform concrete segments construction and the activation of new construction method for free-formed building construction.

• Journal of the Korea Institute of Building Construction
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• v.23 no.5
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• pp.651-662
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• 2023

Recently, research on the use of Building Information Modeling(BIM) for various construction management activities is being actively conducted, and interest in 3D model-based estimation is increasing because it has the advantage of being able to be automatically performed using the attribute information of the 3D model. Therefore, this study aimed that the difference in the quantities is calculated the quantity based on the 2D drawing of a building and is extracted from the 3D model created by the Revit software was compared and tried to find out the cause. The difference in the quantity calculated by the two methods was the largest in the formwork, followed by the smallest in the order of the quantity of rebar and concrete. The reason for this difference is that there is a part where the quantity extraction in the 3D model is not suitable for the quantity calculation standard, and in particular, in the case of formwork, it was difficult to separate only the quantity of the necessary part. In addition, since the quantity of rebar was not separated by member, it was impossible to accurately compare the quantity and identify the cause of the difference. Therefore, it is considered to be the most reasonable to use application software that imports only the numerical information necessary for quantity calculation from the 3D model and applies a separate calculation formula.

• Journal of the Korea Institute of Building Construction
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• v.8 no.2
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• pp.45-52
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• 2008

In today's construction, there has been an increase in the construction of high-rise buildings due to the need to maximize land usage. Framework affects not only the entire construction duration and cost, but also subsequency construction activities such as electrical, mechanical, and finishing works. Especially, proper formwork is a influential factor of productivity in the framwork of reinforced concrete construction. To that reason, a table form of system form is more frequently used than conventional form. However, an initial cost of the table form is high and a reused table form needs for workers to repair damaged table forms. Therefore, the goal of this study is to introduce euro-unit table form. The results from the application of euro-unit table form to high-rise residentia building construction are as follows : (1) The cost of producing table form reduced by 16%, and (2) The time of producing table form was slumped by 35%, and (3) The labor force needed for form work declined 21%.

• Steel and Composite Structures
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• v.34 no.3
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• pp.441-452
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• 2020

Within the French CIFRE research project COMINO, an innovative type of composite beam was developed for buildings that need fire resistance with no additional supports in construction stage. The developed solution is composed of a steel U-shaped beam acting as a formwork in construction stage for a reinforced concrete part that provides the fire resistance. In the exploitation stage, the steel and the reinforced concrete are acting together as a composite beam. This paper presents the investigation made on the load bearing capacity of this new developed steel-concrete composite section. A full-scale test has been carried out at the Laboratory of Structural Engineering of the University of Luxembourg. The paper presents the configuration of the specimen, the fabrication process and the obtained test results. The beam behaved compositely and exhibited high ductility and bending resistance. The shear connection in the tension zone was effective. The beam failed by a separation between the slab and the beam at high deformations, excessive shear forces conducted to a failure of the stirrups in this zone. The test results are then compared with good agreement to analytical methods of design based on EN 1994 and design guidelines are given.

• Computers and Concrete
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• v.20 no.2
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• pp.165-176
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• 2017

Textile Reinforced Cementitious Composite (TRCC) became the most common construction material lately and have excellent properties. TRCC can be employed in the manufacture of thin-walled facade elements, load-bearing integrated formwork, tunnel linings or in the strengthening of existing structures. These composite materials are a combination of matrix and textile materials. There isn't much research done about the usage of polymer modified matrices in textile reinforced cementitious composites. In this study, matrix materials named as fine grained concretes ($d_{max}{\leq}1.0mm$) were investigated. Air entraining effect of polymer modifiers were analyzed and air void content of fine grained concretes were identified with different methods. Aim of this research is to study the effect of polymer modification on the air content of fine grained concretes and the role of defoamer in controlling it. Polymer modifiers caused excessive air entrainment in all mixtures and defoamer material successfully lowered down the air content in all mixtures. Latex polymer modified mixtures had higher air content than redispersible powder modified ones. Air void analysis test was performed on selected mixtures. Air void parameters were compared with the values taken from air content meter. Close results were obtained with tests and air void analysis test found to be useful and applicable to fine grained concretes. Air void content in polymer modified matrix material used in TRCC found significant because of affecting mechanical and permeability parameters directly.

• International Journal of Concrete Structures and Materials
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• v.7 no.1
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• pp.79-93
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• 2013

One of the biggest problems affecting bridges is the transverse cracking and deterioration of concrete bridge decks. The causes of early age cracking are primarily attributed to plastic shrinkage, temperature effects, autogenous shrinkage, and drying shrinkage. The cracks can be influenced by material characteristics, casting sequence, formwork, climate conditions, geometry, and time dependent factors. The cracking of bridge decks not only creates unsightly aesthetic condition but also greatly reduces durability. It leads to a loss of functionality, loss of stiffness, and ultimately loss of structural safety. This investigation consists of field, laboratory, and analytical phases. The experimental and field testing investigate the early age transverse cracking of bridge decks and evaluate the use of sealant materials. The research identifies suitable materials, for crack sealing, with an ability to span cracks of various widths and to achieve performance criteria such as penetration depth, bond strength, and elongation. This paper also analytically examines the effect of a wide range of parameters on the development of cracking such as the number of spans, the span length, girder spacing, deck thickness, concrete compressive strength, dead load, hydration, temperature, shrinkage, and creep. The importance of each parameter is identified and then evaluated. Also, the AASHTO Standard Specification limits liveload deflections to L/800 for ordinary bridges and L/1000 for bridges in urban areas that are subject to pedestrian use. The deflection is found to be an important parameter to affect cracking. A set of recommendations to limit the transverse deck cracks in bridge decks is also presented.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.5-7
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• 2012

Repeated using carpentry workers work at working tools because of occupational low back pain, such as musculoskeletal disorders, occupational diseases are on the rise. For this purpose, through the analysis of musculoskeletal disorders and work tools and studies are underway to improve the working conditions of the workers. However, existing previous studies may not reflect the working tools used for carpentry worker dies when working at a construction site that Therefore, in this study, the work in the form of construction, one of the jobs of worker dies classified according to the working tools of musculoskeletal disorders correlated to analyze. The results of this study are as follows. working tools of a total of seven different dies used in the installation process. Musculoskeletal disorders, waist / drill such correlation was very strong. Also showed that a total of three of the tools used in the formwork dismantling cutter musculoskeletal disorders of the arm / elbow and a very strong correlation.

• Steel and Composite Structures
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• v.13 no.5
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• pp.489-500
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• 2012

Cold-formed steel profile sheets acting as decks have been popularly used in composite slab systems in steel structural works, since it acts as a working platform as well as formwork for concreting during construction stage and also as tension reinforcement for the concrete slab during service. In developing countries like India, this system of flooring is being increasingly used due to the innate advantage of these systems. Three modes of failure have been identified in composite slab such as flexural, vertical shear and longitudinal shear failure. Longitudinal shear failure is the one which is difficult to predict theoretically and therefore experimental methods suggested by Eurocode 4 (EC 4) of four point bending test is in practice throughout world. This paper presents such an experimental investigation on embossed profile sheet acting as a composite deck where in the longitudinal shear bond characteristics values are evaluated. Two stages, brittle and ductile phases were observed during the tests. The cyclic load appears to less effect on the ultimate shear strength of the composite slab.

• Journal of the Korean Society of Safety
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• v.25 no.1
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• pp.57-61
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• 2010

Formwork is a temporary structure that supports its weight and that of fresh concrete as well as construction live loads. Scaffoling is a temporary frame used to support people and material in the construction or repair of buildings and other large structures. It is usually a modular system of metal pipes, although it can be made out of other materials. Bamboo is still used in some Asian countries like China. The purpose of a working scaffold is to provide a safe place of work with safe access suitable for the work being done. In construction site, steel pipes are usually used as scaffolds. In this study, scaffolding systems which is changed according to sleeper and joist space were measured by buckling test. Buckling load of respective scaffolding system was analyzed by structural analysis program(MIDAS). Buckling load of scaffold with/without wall connection and footboard was got by test and structural analysis. According to these results，we know that scaffolding system of case 3 is suitable. Buckling load of scaffold with wall connection is higher than without wall connection. So wall connection is important in scaffoling systems. Footboard in the scaffolding systems is not effective against promotion of buckling load. Finally, the present study results will be used to design scaffolding systems safely in the construction sites.