• 국제강구조저널
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• 제18권5호
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• pp.1483-1496
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• 2018

Negligible research has been conducted to date on how to analyse weakened columns, thus safety risks are still involved when structures are weakened prior to demolition. There are various methods available for demolishing steel structures. One of the most effective methods that has been developed involves pre-cutting steel columns at a certain height, so that the least effort can be used to collapse the structure by means of pulling out some of the columns. This paper presents (a) an experimental setup developed to test the capacity of axially loaded weakened columns, which is used to (b) validate a finite element (FE) model. The two pre-cuts that are presented in this paper are (1) the double window cut and (2) the triangular window cut, which are both commonly used in industry. A column weakened with a double window cut or triangular window cut reduces the axial load capacity by up to 50 and 40%, respectively. The FE models developed predict the axial failure load of weakened columns for a double window cut and triangular window cut are generally within an accuracy of less than 8 and 10%, respectively. It is shown at higher slendernesses the influence of column cuts is less than would be intuitively expected because global buckling becomes dominant.

• 화약ㆍ발파
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• 제30권2호
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• pp.43-51
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• 2012

현재까지 발파해체는 건축물과 토목구조물들을 대상으로 하고 있으나 본 연구에서는 밀폐철재구조물(압력용기) 내부에 물을 채우고 폭약의 힘이 작용하는 해체에 관한 기초연구를 하였다. 일정양의 폭약을 밀폐압력용 기내에 넣고 완전 탄성체로 가정할 수 있는 물($H_2O$)을 압력전달 매개체로 하여 밀폐압력용기의 파괴양상을 관찰하였다. 이때 폭발압력은 Abel의 상태방정식을 이용하여 정량화 하였으며, 그 결과 압력전달 매개체(물)가 있을 경우 밀폐압력용기의 인장강도보다 작은 힘으로 파괴가 발생하였으며, 그렇지 않은 경우에는 약 7.1~8.5배의 폭발압력이 필요하였다. 또한, 압력전달 매개체가 없을 경우(공기만 존재) 폭발압력은 일정값에 도달하기 전까지 파괴에 영향을 미치지 못하고 완전 소산 또는 비산하는 현상을 나타내었다. 실험에 이용한 강철(steel)로 이루어진 밀폐압력용기는 파괴되는 양상에 있어서 대부분 탄성-소성파괴의 형태를 보였으며 최초 항복이 일어나는 지점은 용접부위의 경계부분으로 열소성 변형을 받았다고 판단되는 부분이었다.

• 화약ㆍ발파
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• 제19권1호
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• pp.19-30
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• 2001

본 논문에서는 수상구간의 우물통 기초 철거공법을 약액(팽탕성 과괴제) 주임공법에서 발파공법으로 변경하여 공사기간을 단축시키면서도 주변의 보안물건에 대한 공해를 발생시키지 않고 안전하게 공사하여 원가를 절감한 사례를 중심으로 발파공법을 고찰하였다.

• KIEAE Journal
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• 제11권4호
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• pp.87-94
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• 2011

This study was suggested to develop sustainable durability design system and proposed the plan to evaluate design conditions that meet the intended service life and $LCCO_{2}$ reduction level of reinforced concrete structure easily from the early design stage. For that the W/B and covering depth of the concrete structure were calculated through calculation of service life based on standard specification expression and the quantitative reduction rate of the vertical member of reinforced concrete structure by the calculated W/B was applied. Life cycle of building classified into construction stage, operation stage, maintenance stage, and demolition/disposal stage and the method of $CO_{2}$ evaluation of each stage was proposed. For construction stage, the major construction materials that take up over 80% $CO_{2}$ emitting during building construction were selected and the $CO_{2}$ evaluation method for 5 standard apartment houses was proposed. Also, for operation stage, $CO_{2}$ emission was calculated through calculation of heating load by energy efficiency rating certification system. For maintenance stage, $CO_{2}$ emission was calculated using concept of re-construction by life and for demolition/disposal stage was calculated with the use of construction standard estimate. As a result of the case study by such evaluation methods, 80 years of service life and 17 specifications of sustainable durability design that meet the 40% intended $LCCO_{2}$ reduction level were deduced. The Maximum $LCCO_{2}$ reduction rate was analyzed by 47.2%.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 춘계 학술논문 발표대회 1부
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• pp.119-120
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• 2011

Dome structure to form a space-efficient, applied a lot of beautiful buildings with structural systems, as well as a large space structure in the form of new residential lots have been applied. And domestic demand for housing in the dome with increasing dome house using various materials, are becoming commonplace. But now the Dome House is mainly used in construction steel, wood, stone, FRP construction and building materials per unit area and the high cost, long construction time, energy efficiency, has some disadvantages such as degradation. And structural strength of the structure is weak, the natural ingredients used come from natural damage is so big. In addition, demolition of buildings in trouble when handling the environmental problems has emerged. Recently expanded polystyrene to improve these problems by using the various approaches and research is being attempted and there.

• 화약ㆍ발파
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• 제25권1호
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• pp.53-65
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• 2007

축소모형을 이용한 철근콘크리트 구조물 발파해체 시 구조물의 붕괴거동을 분석하기 위해서는 축소모형 부재에 대한 적절한 축소율 산정과 축소모형 부재를 구성하는 재료의 역학적 특성이 원형 철근콘크리트 부재와 상사되어야 한다. 본 연구에서 축소모형의 상사법칙은 밀도를 기준으로 산정하였고, 콘크리트 표준시방서와 콘크리트 구조설계기준에 의해 축소모형 철근콘크리트의 배합 및 배근을 기술하였다. 또한 축소모형 콘크리트의 축소율은 굵은골재 최대치수를 고려하여 부재 단면 길이를 1/5로 축소하였고, 축소모형 철근의 축소율은 공칭지름을 1/5로 축소하였다. 축소모형에 대한 역학적 실험결과로부터 제안된 상사법칙을 적용함으로써 축소모형 콘크리트의 평균압축강도 및 축소모형 철근의 평균항복강도가 상사관계를 가지는 것으로 나타났다.

• 한국건축시공학회지
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• 제11권5호
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• pp.515-522
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• 2011

As Construction and Demolition (C&D) debris increases every year, systems have been adopted to compel the use of recycled aggregate made from C&D debris, and the use of recycled aggregate in the construction field has increased. But environmental problems linked to the alkalinity of recycled aggregate have occurred, and a study on approaches to lower the alkalinity of recycled aggregate is needed. It was certified by this study that a large amount of recycled aggregate could be carbonated in the C&D debris midterm-treatment field. As a result, the density and the water absorption of recycled aggregate after carbonation reaction was improved, and pH of recycled aggregate was lowered from over 11 to 9.4. X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), and Thermogravimetry/Differential Thermal Analysis (TG/DTA) methods also indicated the carbonation of recycled aggregate.

• 화약ㆍ발파
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• 제36권2호
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• pp.10-18
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• 2018

철골 구조물의 발파해체에 사용하는 성형폭약은 국내외 대부분의 경우에 사용이 제한적이거나 수급이 불가능하여 적용하지 못하는 경우가 많이 발생한다. 이러한 문제를 해결하기 위해서는 산업용 폭약을 사용하여 금속 제트가 발생할 수 있는 장치가 필요하다. 본 연구에서는 금속 제트가 발생하는 강재 절단용 장약용기를 제작하였다. 절단 성능 실험을 통해 두께 25mm의 강판에 대한 장약용기의 절단 성능을 평가하였다. 또한 침투 과정 수치 모사와 절단 성능 실험에서의 결과를 비교하고, 두께 35mm와 70mm의 강판에 대한 절단 성능을 평가하였다.

• 건축역사연구
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• 제22권3호
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• pp.27-36
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• 2013

The purpose of this study is to analyze the process of lots-subdivision within the block of Gaeksa at Dongnae-bu under the rule of Japanese Imperialism. Gaeksa of the old government office was the sanctuary that symbolized the sovereignty. Therefore it was naturally a main object of demolition and then the site was converted to other purpose. And Gaeksa was not only converted into the elementary school and the public market but the historic site also processed to break down for opening the road through Japanese Occupation of Korea. The main reasons of lots-subdivision were the transfer from state property to private ownership and the urban development project. Needless to say, the particular major reason was derived from the intention of Japanese Imperialism to destroy the traditional urban. As a result, Gaeksa can not be recognized the traces of today and contributes to the demolition of the remaining ancient building. Finally the deformed urban structure was left over from destroyed building.

• Structural Engineering and Mechanics
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• 제71권4호
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• pp.417-432
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• 2019

Seismic performance analysis of steel-brace reinforced concrete (RC) frame using topology optimization in highly seismic region was discussed in this research. Topology optimization based on truss-like material model was used, which was to minimum volume in full-stress method. Optimized bracing systems of low-rise, mid-rise and high-rise RC frames were established, and optimized bracing systems of substructure were also gained under different constraint conditions. Thereafter, different structure models based on optimized bracing systems were proposed and applied. Last, structural strength, structural stiffness, structural ductility, collapse resistant capacity, collapse probability and demolition probability were studied. Moreover, the brace buckling was discussed. The results show that bracing system of RC frame could be derived using topology optimization, and bracing system based on truss-like model could help to resolve numerical instabilities. Bracing system of topology optimization was more effective to enhance structural stiffness and strength, especially in mid-rise and high-rise frames. Moreover, bracing system of topology optimization contributes to increase collapse resistant capacity, as well as reduces collapse probability and accumulated demolition probability. However, brace buckling might weaken beneficial effects.