• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.209-217
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• 2021

This paper investigates the effect of high strength hooked-end steel fiber content and aspect ratio on the compressive and flexural performance of concrete. A total of ten mixtures were prepared and tested. Concretes with specific compressive strength of 30 MPa were reinforced with three different aspect ratios (l/d) of steel fibers 64, 67, and 80 and three different percentages of steel fibers 0.25, 0.50, and 0.75% by volume of concrete. Tensile strengths of steel fibers with l/d of 64, 67, and 80 are 2,000, 2,400, and 2,100 MPa, respectively. The compressive and flexural properties of plain and steel fiber-reinforced concrete (SFRC) mixtures were evaluated and compared. The experimental results indicated that the incorporation of high-strength hooked-end steel fibers had significant effects on the compressive and flexural performance of concrete. With the increase of steel fiber content, compressive performances, such as Poisson's ratio and toughness, of concrete were improved. The steel fibers with the least l/d of 67 resulted in a larger enhancement of compressive performances. The residual flexural strength, that is, post-cracking flexural resistance and toughness, of concrete is mainly depended on the dosage and aspect ratio of steel fibers. The residual flexural strength at serviceability (SLS) and ultimate limit state (ULS) defined in fib Model Code 2010 (MC2010) is increased as the fiber content and aspect ratio increase.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.402-405
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• 2003

As Remodeling is proceed in the limited condition that is utilization of existing resource, the selection of remodeling objects and scope are affected by the correlation of building systems. Unexpected problems have occurred in construction phase by lack of the consideration about correlation of building systems; increasing of cost, delaying of schedule etc. Therefore, this research suggests the Building System Correlation Diagram Model and the method for selecting the alternative reasonably in remodeling project.

• Korean Journal of Construction Engineering and Management
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• v.8 no.2
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• pp.136-145
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• 2007

This study analyzes the current usage of SD500 high-strength re-bar in domestic construction sites. Also, an evaluation method was developed to measure economic efficiency of lap splice and coupler splice, which are most commonly used in connection SD500. The evaluation method was applied to construction sites in Seoul in December 2006, and the result revealed that coupler splice is relatively superior in terms of cost efficiency when the re-bar diameter is bigger and the concrete strength is lower.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.72-80
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• 2018

Whilst it is common to construct high-rise buildings and long-span structures in the construction and building industry, there might be a number of problems such as excessive re-bars arrangement, deterioration of concrete quality, unnecessary quantity take-off and so forth. As these types of buildings and structures are getting more popular, it is widespread to apply high-strength materials such as high-strength concrete and re-bars to sustain durability and stability. This research aims to investigate the effectiveness of the high-strength reinforcing bars on the underground parking in a rigid-frame structure. In this study, the reinforcing bars with different yield strength were applied to corroborate the usefulness and practicability of the high-strength re-bars on the underground parking in a rigid-frame structure. The test results show that the quantity of reinforcement bars is lowered, as the yield strength of the re-bars are grown in general. However, the quantity of reinforcement bars on the development and splice has a tendency to increase slightly. Despite of the increase of the development and splice, the total quantity of reinforcing bars was reduced since the increasing ration of the pure quantity is higher than the development and splice. Base on the test results, it would be possible to achieve the reduction of reinforcing bars arrangement and lowering the amount of work to be done during a construction phase. Moreover, the reduced amount of bar arrangement will make it possible to improve workability and constructability of reinforced concrete structures. Ultimately, we will be able to attain improved quality and efficiency of construction using reinforced concrete.

• Landscaping Tree
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• s.105
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• pp.15-17
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• 2008

7월이면 도심의 벽 울타리를 따라 화려하게 꽃으로 장식하며 우리의 마음을 한결 가볍게 해주는 능소화는 중국 원산으로 낙엽활엽의 덩굴성 식물로 주로 중부 이남 지역에서 사찰의 관상용으로 식재하였으나 요즘은 전국 어디서나 쉽게 볼 수 있고, 사람들에게 많은 사랑을 받고 있는 식물이다. 특히 도심의 고건축물이나 휴식공간에 식재하면 나팔 모양의 꽃과 색상이 화려하면서 점잖고 기품이 있어 동양적인 아름다움을 함께 누릴 수 있는 나무이다. 또한 공해에도 비교적 강하기 때문에 도심의 정원수나, 조경수로 보급 가능하다. 해풍과 염기에 강하며 해안지역에서도 잘자라며 비옥한 사질양토에서 생장이 좋다. 이런 능소화를 가해하는 해충으로 뒷노랑얼국나방과 미국흰불나방 등이 피해를 주고 있어 이들에 대한 생태 및 방제법을 간략하게 소개하고자 한다.

• The Magazine for Energy Service Companies
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• s.6
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• pp.66-72
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• 2000

이 보고서는 일본의 ''ESCO사업실증위원회''에서 통신산업성의 고효율 에너지 이용형 건축물 개수모델사업의 보조를 받는 건물 가운데 ESCO 사업을 염두에 두고 사업을 벌인 4모델에 대하여 에너지절약 진단서 조사, 듣기조사, 현장조사 등을 실시하여 개수계획의 타당성을 검토한 결과이다. 보고서 내용중 중요 부분을 발췌하여 우리나라 ESCO사업과 비교해 보고자 한다.

• Electric Engineers Magazine
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• v.196 no.12
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• pp.14-20
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• 1998

병원 전기설비는 일반 업무용 건축물과는 달리 순간 정전도 허용하지 않는 대형컴퓨터, 의료용 전기기기, 사무자동화기기 등을 사용하고 있어 특히 전원설비의 고신뢰성, 안전성이 요구되는 비, 본지에서는 병원 전기설비의 안전기준을 살펴보고 조사대사 병원의 수변전설비 구성 현황, 변전시설밀도, 수용률, 최대수요전력의 발생 실태를 검토하고자 한다.

• The Magazine for Energy Service Companies
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• s.5
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• pp.66-73
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• 2000

이 보고서는 일본의 ''ESCO 사업실증위원회''에서 통산산업성의 고효율 에너지 이용형 건축물 개수모델사업의 보조를 받는 건물 가운데 ESCO사업을 염두에 두고 사업을 벌인 4모델에 대하여 에너지절약 진단서 조사, 듣기조사, 현장조사 등을 실시하여 개수계획의 타당성을 검토한 결과이다. 보고서 내용중 중요 부분을 발췌하여 우리나라 ESCO사업과 비교해 보고자 한다.

• Electric Engineers Magazine
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• v.205 no.9
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• pp.47-52
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• 1999

건축물의 대형화, 정보화, 자동화 등으로 전력수요가 급증하면서 전력설비가 대용량화되고 복잡해져서 한 순간이라도 정전이 발생하면 유, 무형의 경제적 손실이 따르게 된다. 이와 같은 배경에서 과거보다도 전력설비의 고안정도, 고신뢰성이 한층 요구되고 있으며 특히 수, 변전설비에 대한 안전관리의 중요성이 날로 부각되고 있는 실정이다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.111-116
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• 2022

Recently, building structures tend to be super high-rise and large-scale with the development of concrete technology. When high-rise building is constructed of reinforced concrete structure, it has a disadvantage that its own weight increases. Light weight aggregate(LWA) was developed to compensate for these shortcomings. Manufacturing concrete using these light weight aggregates has the advantage of reducing the self weight of the reinforced concrete structure, but has a disadvantage in that the strength of the concrete is reduced. In this study, an experimental study was conducted to investigate the strength characteristics of hardened cement according to the presence or absence of surface coating of lightweight aggregates. As a result, in terms of compressive strength, the surface-coated lightweight aggregate exhibited higher strength than the uncoated lightweight aggregate. Also, it was considered that this is because the interfacial voids of the surface coated lightweight aggregate mixed cement hardened body were filled with blast furnace slag fine powder particles.