• Title/Summary/Keyword: strutural engineering

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Traring instability of crack based on J-integral (J-적분을 이용한 균열 찢어짐 불안정성에 관한 연구)

  • Lee, Hong-Seo;Kim, Hui-Song
    • Journal of the Korean Society for Precision Engineering
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    • v.6 no.3
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    • pp.78-89
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    • 1989
  • Applicability of tearing modulus based on J-integral proposed by Paris et al is investigated using compact tension specimens of strutural alloy steel (SCM4). Both general fracture test and instability fracture test are performed. The applied tearing modulus, ( $T_{j}$)app estimated from the real load vs. crack growth curve measured from experiments are compared with that estimated from the limit load vs. crack growth curve. The results are : (1) the $T_{j}$parameter could be applied to predict crack growth instability : (2) The use of ( $T_{j}$)app estimated from the load vs. crack growth curve, proposed in this study could be well predicted crack growth instability instead of that estimated form the limit load vs. crack growth curve.e.

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Risk evaluation of steel frames with welded connections under earthquake

  • Song, Jianlin;Ellingwood, Bruce R.
    • Structural Engineering and Mechanics
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    • v.11 no.6
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    • pp.663-672
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    • 2001
  • Numerous failures in welded connections in steel moment-resisting building frames (SMRF) were observed when buildings were inspected after the 1994 Northridge Earthquake. These observations raised concerns about the effectiveness of such frames for resisting strong earthquake ground motions. The behavior of SMRFs during an earthquake must be assessed using nonlinear dynamic analysis, and such assessments must permit the deterioration in connection strength to capture the behavior of the frame. The uncertainties that underlie both structural and dynamic loading also need to be included in the analysis process. This paper describes the analysis of one of approximately 200 SMRFs that suffered damage to its welded beam-to-column connections from the Northridge Earthquake is evaluated. Nonlinear static and dynamic analysis of this SMRF in the time domain is performed using ground motions representing the Northridge Earthquake. Subsequently, a detailed uncertainty analysis is conducted for the building using an ensemble of earthquake ground motions. Probability distributions for deformation-related limit states, described in terms of maximum roof displacement or interstory drift, are constructed. Building fragilities that are useful for condition assessment of damaged building structures and for performance-based design are developed from these distributions.

Structural Effect Evaluation of an Apartment Building Due to the Water Tank under Earthquake Load (지진발생시 아파트 옥탑층 물탱크의 구조적 영향평가)

  • 정은호
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.1
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    • pp.29-40
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    • 1999
  • High-rise building for dwelling has many factors to be considered in structural aspects. In particular, the higher the building, the bigger the lateral loads such as wind and earthquake due to its dynamic characteristics. Unlike the wind load, the earthquake load, even if the shape of the structures are similar, depends on structural characteristics and it is difficult to predict. For an apartment building, the water tank in the penthouse, due to its heavy weight, changes the behavior of a building when the earthquake occurs. The purpose of this study is to determine how the water tank affects the behavior of an apartment building when earthquake occurs. Dynamic analysis was accomplished on two cases - 1) water tank is considered 2) water tank is not considered - to understand how it affects the behavior of a high-rise apartment building. Structural design was accomplished to understand how the water tank and the peak acceleration affects each structural member. The effect of the water tank on the response of structure was large. Elsewhere the water tank has no effect on the design of a strutural member. However some structural members were affected when the peak acceleration of an earthquake is 0.4g.

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Productivity Analysis for Strutural Formwork Using 3D BIM (3D BIM을 활용한 골조 거푸집 공사의 생산성 분석에 관한 연구)

  • Choi, Chang-Hoon;Park, Young-Jin;Soh, Ji-Yoon;Kim, Sung-Yeon;Lee, Junbok
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.4
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    • pp.292-300
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    • 2014
  • The construction progress control is very important because there are many unexpected factors affecting time schedule delay and cost overruns. A complicated measure including item quantity and inherent time and costs is used to monitor the progress. Another element to be considered is a productivity, which is cost effectiveness because productivity is primarily measured by the costs. Productivity is stated as constant in-place value divided by inputs such as worker-hour. The main purpose of this paper is to analyze the productivity of structural formwork using a 3D BIM. In order to achieve the research objective, an integrated model of a BIM with a daily foreman's report is developed. The quantities being extracted from a 3D model and information are integrated with manpower utilized. The developed model is applied to a case project to measure and analyze the productivity in terms of individual building and work crew team. The results are discussed and further research topics will be addressed.