• Advances in Computational Design
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• v.8 no.4
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• pp.295-307
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• 2023

This paper presents an optimization of the reinforced concrete ribbed slab in terms of minimum CO₂ emissions and an economic justification of the final optimal design. The design variables are six geometry variables including the slab thickness, the ribs spacing, the rib width at the lower and toper end, the depth of the rib and the bar diameter of the reinforcement, and the seventh variable defines the concrete strength. The objective function is considered to be the minimum amount of carbon dioxide gas (CO₂) emission and at the same time, the optimal design is economical. Seven significant design constraints of American Concrete Institute's Standard were considered. A robust metaheuristic optimization method called improved dolphin echolocation and ant colony optimization (IDEACO) has been used to obtain the best possible answer. At optimal design, the three most important sources of CO₂ emissions include concrete, steel reinforcement, and formwork that the contribution of them are 63.72, 32.17, and 4.11 percent respectively. Formwork, concrete, steel reinforcement, and CO₂ are the four most important sources of cost with contributions of 67.56, 19.49, 12.44, and 0.51 percent respectively. Results obtained by IDEACO show that cost and CO₂ emissions are closely related, so the presented method is a practical solution that was able to reduce the cost and CO₂ emissions simultaneously.

• 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 of Building Construction
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• v.17 no.6
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• pp.587-594
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• 2017

The construction industry generates the greatest number of disasters. Laborer injury at construction sites is mostly reported by small and mid-sized construction sites. Moreover, of the injuries, the greatest number is related to formwork. The objective of this study is to propose a checklist of the risk factors of formwork, in which industrial injuries occur most frequently in small and mid-sized construction sites, with which safety management can be done thoroughly. Risk factors and preventive measures are derived by analyzing 9,396 industrial disasters occurring at construction sites in Korea. The checklist drawn in this study was reviewed by five specialists in safety management, and applied to construction sites to verify its applicability. In a result, applying the checklist to the site showed that the safety management system of small and medium-sized construction sites were insufficient. It is expected to contribute to the effective safety management of small and mid-sized construction sites.

• Journal of the Korea Institute of Building Construction
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• v.11 no.2
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• pp.116-126
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• 2011

Recently, eco-friendly energy has been employed in diverse fields of industry in order to reduce environmental pollution and secure a new growth engine. In particular, practical applications of photovoltaic energy, such as building integrated photovoltaic systems, have been implemented to the construction industry based on the extensive interest in photovoltaic power as an unlimited and sustainable energy. While the construction of a high-rise building requires large amounts of energy, methods of reducing energy consumption in the construction phase have rarely been studied. Based on this motivation, the research proposes a photovoltaic based formwork system (PVFS), and then performs a design and feasibility analysis for its application to the construction of a high-rise building. Using a case study, the research implements various analyses, including area, position, and total allowable weight required by PVFS, and evaluates the influences of PVFS on the construction processes, as well as its economic feasibility. The proposed PVFS can be adopted to a real-world project in the near future, depending on the advancement of technology and economic feasibility. The results of this research will contribute to establishing a construction environment that promotes a reduction of energy consumption by using eco-friendly energy in the construction phase.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.6
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• pp.55-66
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• 2011

The purpose of this study was to develop an efficient process in the design and construction of a 1:5 scale 10-story R.C. apartment building model for an earthquake simulation test. The reduction ratio of the specimen was determined by the size ($5m{\times}5m$) and pay load (600kN) of the available shaking table and the availability of model reinforcements. For efficiency and quality control of the reinforcement work, prefabrication was used. Construction was conducted in two steps, the wall in one step, and another step for the slab, because it was impossible to remove the formwork of a wall if the walls and slabs in a story were constructed in one step. The slip form construction method was used repetitively for walls. The formwork of a wall was made with veneer and acryl plate on each side, so it was possible to check the quality of the concrete placing. To construct this model, it took roughly six months with five full-time research assistants, for a total of 602 man days of labor in construction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.525-534
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• 2010

A road curbstone is a structure installed at the boundary of the sidewalk and the street with the objectives of road drainage, drawing attention and such. The current general construction method of curbstones places foundation concrete for the curbstones first, waits until the concrete reaches the strength to support the curbstones, places the curbstones on top, and then places the gutter and rear filling concrete. Such method has the issues of poor compaction and weakened bond strength of concrete due to split placing of concrete, and causes the curbstones to easily separate due to vehicle impact or earth pressure, in turn creating maintenance costs and spoiling the aesthetics. To improve such conventional construction methods, an all-in-one method was developed using formwork rail and jig where both the curbstones and gutter can be worked at the same time, and to evaluate the structural performance, static tests of lateral loading test, pullout test, and bending test were executed, and dynamic tests such as pendulum test and actual vehicle impact test were executed. In all tests, the all-in-one construction method using formwork rail and jig was shown to be superior to the conventional construction method by the increase of construction quality and bond strength of concrete.

• Magazine of the Korea Concrete Institute
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• v.14 no.5
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• pp.21-26
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• 2002

구의 아크로리버 현장은 서울의 동쪽에 위치한 지하 5층, 지상 37층과 지상 22/26/29층 2개 동의 업무/판매시설 및 공동주택을 신축하는 주상복합형 프로젝트로서 주변에 강변시외버스터미널과 테크노마트가 바로 인접하여 평소 유동인구가 매우 많은 곳에 위치해 있다. (그림 1)은 구의 아크로리버의 조감도이며, 공사개요는 (표 1)과 같다.(중략)

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.51-56
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• 1993

This is a part a study on the development of High-Performance Concrete ; about experimental results from several test methods to estimate workability in fresh concrete and influences of concrete mix design that affects properties of super-flowing concrete. Super-flowing concrete can be filled in a formwork without any vibration because of its excellent workability of passing narrow space and filling complicated shaped mold, new test methods should be used to estimate the workability and rhelogy in super-flowing concrete instead of slump test method in conventional concrete.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.10a
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• pp.106-112
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• 1993

This paper presents the optimum design of reinforced concrete conical shell which is fixed at the base and free at the top. The calculation of stresses is done using the SMAP(Segmented Matrix Analysis Package)program which uses the simple finite element method of analysis. The objective function contains the ratios of the unit cost of reinforcements and formwork to that of concrete. To Simplify the optimization procedure, the final optimum design of conical shell is obtained by combining the result of each element. The results are presented and discussed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.39-40
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• 2016

The aim of this research was evaluating strength characteristics of foamed concrete using Ladle Furnace slag with GGBFs. For all mixtures, because of the early setting and strength development, it was possible to deform the formwork and measure the compressive strength within 3 hours.