• Steel and Composite Structures
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• 제6권1호
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• pp.15-31
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• 2006

Beams with web openings are an attractive system for multi-storey buildings where it is always desirable to have long spans. The openings in the web of steel beams enable building services to be integrated within the constructional depth of a floor, thus reducing the total floor depth. At the same time, the increased beam depth can give high bending moment capacity, thus allowing long spans. However, almost all of the research studies on web openings have been concentrated on beam behaviour at ambient temperature. In this paper, a preliminary numerical analysis using ABAQUS is conducted to develop a general understanding of the effect of the presence of web opening on the behaviour of steel beams at elevated temperatures. It is concluded that the presence of web openings will have substantial influence on the failure temperatures of axially unrestrained beams and the opening size at the critical position in the beam is the most important factor. For axially restrained beams, the effect of web openings on the beam's large deflection behaviour and catenary force is smaller and it is the maximum opening size that will affect the beam's response at very high temperatures. However, it is possible that catenary action develops in beams with web openings at temperatures much lower than the failure temperatures of the same beam without axial restraint that are often used as the basis of current design.

• Steel and Composite Structures
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• 제5권2_3호
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• pp.193-202
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• 2005

This paper describes recent developments in composite construction and their effect on codified design procedures in the UK. Areas of particular interest include: rules on shear connection, design of beams with web openings, serviceability limits, such as floor vibrations, and fire safe design. The design of cellular beams with regular circular openings now includes generalized rules for web-post buckling, and for the development of in-plane moment in the web-post for asymmetric sections. Closed solutions for the maximum shear force due to limits on web-post bending or buckling are presented. The fire resistance of cellular beams is also dependent on the temperature of the web-post, and for closely spaced openings. It is necessary to increase the thickness of fire protection to the web. For serviceability design of beams, deflection limits and natural frequency and response factor for vibration are presented. It may be necessary to use stricter limits for certain applications.

• 터널과지하공간
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• 제6권1호
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• pp.10-18
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• 1996

Arched openings are generally excavated in underground construction works. Since stress distribution around openings depends on geological structure in rock mass, any shape of arched openings fully conformed with in-situ stress condition should be recommended to maintain mechanical safety of structures. Shape of arched openings is specified by both roof curvature and height-width ratio, and especially this report presents deformation behaviors related with roof curvature. Scale model tests and numerical studies of various shaped openings are conducted, where rectangular opening shows the greatest convergence. Through the anlayses of various arched opengings, as radius of roof curvature is increased, roof lowering and sidewall closure are remarkably increased, whereas floor heaving is increased little by little. By the way, it is useful that displacements of openings are roughly estimated in the stage of preliminary investigation. To find out elastic displacements of arched openings with any roof curvature, regressional formula and charts by least square method are represented. In addition elastoplastic deformation behavoirs of arched openings concerning associated adn non-associated flow rule are discussed.

• 한국화재소방학회논문지
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• 제26권2호
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• pp.90-96
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• 2012

외장재에 의한 수직화재확산은 확산속도가 구획화재에 비해 매우 빨라 이에 대한 화재의 특성 분석이 요구된다. 본 연구에서는 건물 외부에서 발생한 화재가 연소 확대되면서 수직으로 상승하여 개구부를 통해 유입되는 화재의 성상에 대해서 외장재로 널리 사용되는 심재가 폴리에틸렌인 일반 알루미늄복합패널에 대해 화재시뮬레이션을 적용하여 연구하였다. 그 결과, 수직확산화염은 화재초기에 2층까지 상승하는 데는 약 135초가 걸렸지만 10층까지는 470초, 최고층인 30층까지 상승하는 데는 711초에 도달하는 것으로 분석되어 고층부로 갈수록 난류 및 외장재 설치공간의 연돌효과에 의해서 급격히 확대되는 것을 알 수 있었다. 이러한 연구 결과로 외장재가 설치된 건축물의 화재 시 개구부를 통한 화재는 동시다발적으로 그 건물의 내부에 확대되는 심각성을 확인할 수 있었다.

• 한국강구조학회 논문집
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• 제16권5호통권72호
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• pp.575-586
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• 2004

본 논문은 새롭게 개발된 춤이 깊은 데크 플레이트(이하 Deep Deck) 및 비대칭 H형강 하부플랜지에 플레이트를 용접한 비대칭 철골보로 구성된 매립형(슬림플로어) 합성보의 웨브면에 개구부를 가진 유공 합성보의 휨성능에 관한 실험적 연구이다. 실험은 철골보 춤(250mm, 300mm), 개구부의 위치 및 가력조건에 따라 5개의 유공 합성보에 대한 단순지지 휨실험 수행하였다. 실험결과, 매립형 유공합성보는 전단연결재를 사용하지 않고도 콘크리트의 면내 부착력에 의해 충분한 합성작용을 하는 것으로 나타났고, 개구부 주변이 콘크리트에 의해 구속되어 개구부의 보강없이 충분한 구조적 성능을 발휘할 수 있음을 확인하였다.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.353-360
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• 2022

Due to the dense and complicated working environment, the construction industry is susceptible to many accidents. Worker's fall is a severe problem at the construction site, including falling into holes or openings because of the inadequate coverings as per the safety rules. During the construction or demolition of a building, openings and holes are formed in the floors and roofs. Many workers neglect to cover openings for ease of work while being aware of the risks of holes, openings, and gaps at heights. However, there are safety rules for worker safety; the holes and openings must be covered to prevent falls. The safety inspector typically examines it by visiting the construction site, which is time-consuming and requires safety manager efforts. Therefore, this study presented a worker-driven approach (the worker is involved in the reporting process) to facilitate safety managers by developing integrated computer vision and inertia sensors-based mobile applications to identify openings. The TensorFlow framework is used to design Convolutional Neural Network (CNN); the designed CNN is trained on a custom dataset for binary class openings and covered and deployed on an android smartphone. When an application captures an image, the device also extracts the accelerometer values to determine the inclination in parallel with the classification task of the device to predict the final output as floor (openings/ covered), wall (openings/covered), and roof (openings / covered). The proposed worker-driven approach will be extended with other case scenarios at the construction site.

• KIEAE Journal
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• 제8권6호
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• pp.63-70
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• 2008

Slim floor construction is becoming used throughout many countries. It combines the advantages of flat slab construction with significant inherent resistance to fire. The slim floor system with web openings leads to the reduction of its self-weight. Although the system has enough strength and stiffness, it is necessary to evaluate and improve the effects of dynamic vibration to be able to annoy the residents. Thus, this study evaluates the serviceability of vibration effects based on the dynamic test of five slim composite beams. Based on the experimental results, the initial stiffness and natural frequency of all specimens exhibit the similar trend regardless of the opening and the shape of cross section. The decrease in natural frequency is deeply related to the reduction in the stiffness of specimens and thus, it can be concluded that the damage of slim composite floor can be detected by the measurement of natural frequency instead of the load-carrying capacity and the stiffness.

• 한국강구조학회 논문집
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• 제18권5호
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• pp.607-614
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• 2006

건축물의 바닥판에 대한 데크플레이트 합성슬래브 시스템의 사용이 점차 확대되어 최근에는 오피스 빌딩을 중심으로 널리 사용되고 있으나, 각종 건축 설비의 설치를 위하여 슬래브의 천공이 무분별하게 이루어지고 있다. 따라서, 본 연구에서는 건축 설비에 의하여 구조물의 주 구조체인 슬래브에 천공에 의한 개구부가 있는 경우, 휨 부재로써의 역학적 성능 저하에 대하여 실험을 통하여 분석하고자 한다. 본 연구에서는 골형 합성데크 슬래브에 대하여 개구부의 형태와 위치에 따라 시험체를 제작하여 정적 가력 실험을 수행하였다. 2점 정적 반복 가력을 통하여 하중 변위 관계 그래프를 도출하였으며 각 시험체의 연성과 에너지 소산 능력을 산출하였다.

• 한국주거학회논문집
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• 제12권3호
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• pp.141-148
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• 2001

To design mechanical ventilation for bathroom of apartment houses where air supply and exhaust are taken into consideration, mock-ups of ventilation systems, widely used in bathroom of apartment houses with an area of 100$\textrm{m}^2$, were made and installed in a laboratory. These ventilation mock-ups were available for control of air supply and exhaust, and the sizes of supply openings were 40cm${\times}$1cm, 40cm${\times}$3cm, and 40cm${\times}$5cm. They were installed at five positions, spaced 45cm at a height of 5cm from the floor. The exhaust fan was designed for its operating voltage to be set to five steps(100V, 130V, 150V, 180V and 220V) in order to control its air flow rates. When the size and position of each supply opening were changed with the wind velocity of the exhaust fan set to the step 5, the ventilation rates were measured and analyzed by the concentration decay method of tracer gas method, in order to present an efficient mechanical ventilation system. The results of the study revealed that the ventilations rates would increase in the presence of supply openings, compared to the absence of supply openings, and that the larger the size of the supply opening, the more the ventilation rates. Therefore, it was found necessary to take air supply into consideration.

• 설비공학논문집
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• 제26권7호
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• pp.335-342
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• 2014

The big issue in fire and life safety protection in atriums is that hot smoke can spread vertically via the atrium openings, and impact atrium floors remote from the fire. Three different strategies to provide fire and life safety protection for atrium space were evaluated in this study, using the FDS model. Strategy A is the atrium protection approach addressed in the Korean Building Fire Protection Code, where atria are required to be enclosed with fire shutters from the $2^{nd}$ floor to the atrium top, and the ground floor is allowed to open to the atrium; in this case, no smoke control is required. Strategy B is the atrium protection approach, with smoke control provided in accordance with NFPA 92B; in this case, no atrium floor is enclosed. Strategy C is the atrium protection approach, in which some of the upper atrium floors are enclosed (the case of the top atrium floor being enclosed is evaluated in this study), and atrium smoke control is also provided to protect the lower atrium floors.