• Title/Summary/Keyword: Structural Safety

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Robust Design of Structural and Mechanical Systems using Concept of Allowable Load Set (허용하중집합 개념을 이용한 기계/구조 시스템의 강건 설계)

  • Kwak, Byung-Man
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.333-338
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    • 2007
  • The concept of "Allowable Load Set (ALS)" introduced by the author allows an easy understanding of load and strength characteristics of a structure in relation to its integrity under uncertainties. Two criteria of safety are introduced: A relative safety index denotes the distance to the boundary of the ALS and a normalized safety index is a distance in terms of functional value. They have been utilized in several examples, including multi-body mechanical systems such as a biomechanical system. Both formulations amount to robust designs in the sense that designs most insensitive to uncertainties are obtained in the context of newly defined safety indices, without using any input probability information.

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Structural Safety Evaluation of Stabbing System for Pre-Piling Jacket Substructure Considering Pile Construction Errors (파일의 시공오차를 고려한 스태빙시스템의 구조안전성 평가)

  • Youngcheol Oh;Jaeyong Ryoo;Daeyong Lee
    • Journal of Wind Energy
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    • v.14 no.3
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    • pp.109-119
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    • 2023
  • A structural safety evaluation was conducted for the stabbing system for the pre-piling jacket substructure currently being developed in South Korea, considering pile construction errors due to its lateral movement that may occur during construction in the ocean. Based on (1) the maximum stress generated by the stabbing system, (2) the maximum rotational displacement of the guide cone, and (3) the maximum stress generated by the horizontal hydraulic pressure cylinder, the structural safety of the stabbing system was examined under the initial loading condition and three possible load combinations during its construction. In order to evaluate the structural safety of the stabbing system, a concept of stress safety factor (= Yield stress / Max. Von-Mises stress) was used. It was found that the stabbing system considered in this study has a sufficient margin of safety.

Evaluation of Dynamic Structural Safety of Aged Finger Pier (노후 잔교식 부두의 동적구조 안전성 평가에 관한 연구)

  • 이성우;이상호;지기환
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1993.04a
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    • pp.45-52
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    • 1993
  • Evaluation of structural stability of aged wharf structure of pier type is of great importance for both safety and rehabilitation, Series of field dynamic experiments were performed for berthing impact and the results were used to calibrate analysis model. Through dynamic analysis for design, berthing impact safety of old wharf structure were evaluated. In this paper the procedure and results of experiments and analysis are presented.

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Structural Safety Assessment of a Concrete-filled Base Frame Supporting a Motor for Centrifugal Compressor Drives (원심식 압축기 구동용 모터 베이스 프레임의 콘크리트 타설에 따른 구조안전성 평가)

  • Kim, Min-Jin;Lee, Jae-Hoon;Han, Jeong-Sam
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.1
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    • pp.1-8
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    • 2016
  • In this paper, we perform structural analysis for a base frame which is used to support a motor for large centrifugal compressor drives and a safety assessment according to the concrete placement. First, the structural analysis about four loading conditions for the motor base frame was conducted and the structural safety was evaluated through both the maximum distortion energy theory and Mohr-Coulomb theory. It was possible to perform a more reasonable safety evaluation against local stresses occurring at the discontinuous portion of the fragile structural members by applying the safety assessment through ASME VIII Div. 2. In addition, the motor base frames with and without the internal concrete placement were quantitatively compared by the structural analysis and safety evaluation using ASME code and it was found to improve the structural integrity due to the concrete placement.

Enhancement of Structural Safety Using Piezoelectric Bimorph

  • Loh, Byoung-Gook
    • International Journal of Safety
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    • v.6 no.1
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    • pp.22-25
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    • 2007
  • Damping out high frequency low amplitude structural vibrations using PZT bimorph is presented. Static and Dynamic analyses of the piezoelectric bimorph bender were performed. Three layer piezoelectric actuators were modeled with SOLID5 coupled-field elements using ANSYS. Static deflection and modal analyses of the piezoelectric bimorph bender are presented. Proper tuning of the values of the resistor and inductor in the shunt circuit is required for maximum vibration suppression.

Structural performance monitoring of an urban footbridge

  • Xi, P.S.;Ye, X.W.;Jin, T.;Chen, B.
    • Structural Monitoring and Maintenance
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    • v.5 no.1
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    • pp.129-150
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    • 2018
  • This paper presents the structural performance monitoring of an urban footbridge located in Hangzhou, China. The structural health monitoring (SHM) system is designed and implemented for the footbridge to monitor the structural responses of the footbridge and to ensure the structural safety during the period of operation. The monitoring data of stress and displacement measured by the fiber Bragg grating (FBG)-based sensors installed at the critical locations are used to analyze and assess the operation performance of the footbridge. A linear regression method is applied to separate the temperature effect from the stress monitoring data measured by the FBG-based strain sensors. In addition, the static vertical displacement of the footbridge measured by the FBG-based hydrostatic level gauges are presented and compared with the dynamic displacement remotely measured by a machine vision-based measurement system. Based on the examination of the monitored stress and displacement data, the structural safety evaluation is executed in combination with the defined condition index.

Development of a Structural Safety Evaluation System for Stone Voussoir Arch Bridges (석조 홍예아치교의 구조적 안정성 평가시스템 개발)

  • Kim, Nam-Hee;Koh, Hyun-Moo;Hong, Sung-Gul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.1
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    • pp.15-23
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    • 2009
  • Masonry structures that are very strong in compression fail due to the instability of structural shape of geometry rather than the material stress limit. Considering such structural behavior, the use of the limit theorem that focuses on structural collapse mechanisms is more appropriate for the evaluation of the structural safety of stone voussoir arch bridges. This paper is to investigate structural performance of the stone arch bridges constructed using dry construction method in Korea based on the limit theorem and to exploit the result to develop a system for an structural safety margin. It is expected that this study will help us understand structural behavior of stone voussoir arch bridges in Korea. Also, it will provide a guideline to make engineering decision from the viewpoint of the maintenance of cultural heritages.

A Study on the Structural Safety of the Roof Improvement Project (슬레이트지붕 개량사업 구조안전성 검토)

  • Kang, Kyung-Soo
    • Journal of the Korean Institute of Rural Architecture
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    • v.20 no.1
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    • pp.19-26
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    • 2018
  • The roof improvement project is being carried out under the government's leadership for the sake of national welfare. The project is to replace the asbestos slate roof with a metallic one. In this study, the structural safety of the improved roof was examined and the project guidelines were reviewed. The causes of the roof damage were investigated and the structural analysis was performed for the roof frame subject to wind and snow loads. Metallic roof assemblies have higher strength and load resistance capability than usual slate ones, so the structural safety is governed by the frame. The stresses of the roof frame elements caused by the wind and snow loads were analyzed according to roof frame with various spacings between the rafters and the purlins. Wind load analysis was performed by 24, 28, and 38 m/sec of the basic wind speed. Snow load analysis was carried out by 0.5, 1.0 and $2.0kN/m^2$ of the ground snow load. As the analysis result, the current spacing and the size of the lumber did not satisfy the Korean building code specification. To secure the safety of the roof improvement project, the spacing of the roof frame elements and the size of the lumber should be determined based on the analysis results by structural engineers.

A Study on the Structural Safety Analysis for Vinyl House at Wind Load (비닐하우스의 풍하중 구조안전성 검토에 관한 연구)

  • Paik, Shinwon
    • Journal of the Korean Society of Safety
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    • v.34 no.5
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    • pp.72-77
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    • 2019
  • Vinyl house consists of main rafter, lateral member, clamps and polyethylene film. Many vinyl houses are used to grow fruits, flowers and vegetables in the countryside. Due to climate change, vinyl houses are often destroyed by strong winds or typhoons in summer. Many farmers suffer great economic damage from the collapse of vinyl houses. So it is very important to build a safe vinyl house and find a method to withstand this heavy wind load. In this study, a structural analysis was performed on four types of vinyl houses(10-single-4, 10-single-6, 10-single-7, 10-single-10). In addition, axial force and flexural moment are obtained from the structural analysis of four types of vinyl house. For these four types of vinyl house, structural safety was reviewed by obtaining the combined stress ratio by the strength design method. This structural review showed that the specifications for the vinyl house proposed in the design are not safe. Especially, the result of structural analysis for four types of vinyl house showed that the vinyl house structure constructed as a standard was a very dangerous structure. Therefore, it is necessary to devise diverse methods in order to make vinyl houses structurally safe for heavy wind load in the future. Also a variety of manual development is needed to prevent the collapse of vinyl houses at heavy wind load.

In-structure Response Evaluation of Shear Wall Structure via Shaking Table Tests (진동대 실험을 통한 전단벽 구조물의 층응답 특성 평가)

  • Jung, Jae-Wook;Ha, Jeong-Gon;Hahm, Daegi;Kim, Min Kyu
    • Journal of the Earthquake Engineering Society of Korea
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    • v.25 no.3
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    • pp.129-135
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    • 2021
  • After the manual shutdown of the Wolseong nuclear power plant due to an earthquake in Gyeongju in 2016, anxiety about the earthquake safety of nuclear power plants has become a major social issue. The shear wall structure used as a major structural element in nuclear power plants is widely used as a major structural member because of its high resistance to horizontal loads such as earthquakes. However, due to the complexity of the structure, it is challenging to predict the dynamic characteristics of the structure. In this study, a three-story shear wall structure is fabricated, and the in-structure response characteristics of the shear wall structure are evaluated through shaking table tests. The test is performed using the Gyeongju earthquake that occurred in 2016, and the response characteristics due to the domestic earthquake are evaluated.