• Title/Summary/Keyword: Allowable load

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Structural reliability analysis of offshore structure at cold region (저온해역에서의 해양구조물에 대한 구조신뢰성 해석)

  • 이주성
    • Journal of Ocean Engineering and Technology
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    • v.11 no.3
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    • pp.8-19
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    • 1997
  • In this study an adequate type of offshore structure at the Sakhalin region as cold region is proposed and its structural design results are presented based on the reliability analysis. Structural safety assessment has been carried out for the proposed offshore structure at the Sakhalin area as designed by the reliability method. And a rational design procedure is presented based on the reliability analysis. Followings are drawn through the present study : - Four colum TLP structure is proposed as an adequate offshore structure type at the cold region like the Sakhalin region and the reliability-based structural design results are presented. It is seen that the proposed type is a more adequate and economic than the fixed type. - Safety assessment of the proposed structure applying the extended incremental load method is performed. - Referring the allowable safety level for offshore structures it has been found present TLP structure has sufficient structural safety at the system level as well as at the component level.

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An Evaluation Scheme of Torsional Irregularity for Seismic Design of Hanok (한옥의 내진설계를 위한 비틀림비정형 평가 방안)

  • Kim, Yeong-Min
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.10
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    • pp.191-198
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    • 2019
  • In this paper the evaluation scheme for determining torsional irregularity of Hanok has been proposed. The proposed method can evaluate torsional irregularity of Hanok easily only with characteristics of Hanok shapes, arrangement of lateral load resisting frames and their lateral stiffness without time consuming and complicate 3-dimensional structural analysis. The proposed formula is expressed as allowable maximum eccentricity, and torsional irregularity is evaluated by comparing this value with actual eccentricity. The applicability of the proposed scheme was evaluated by applying it to the line shape plan Hanok with two symmetrically arranged walls and the result was expressed by formula and graph. The results showed that the allowable maximum eccentricity is 10% of plan dimension perpendicular to the seismic load when the walls are placed at the extreme end. The proposed formula was expressed as a generalized formula so it can be applied generally to the various plan shape and wall arrangement of Hanok.

Load-Carrying Capacity Assessment of Deteriorated Rural Bridge

  • Kim, Han-Joong;Kim, Jong-Ok;Yang, Seung-Ie
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.44 no.7
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    • pp.36-45
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    • 2002
  • Most of rural bridges have passed 30 years of age since they were built, which have to support unexpected overload caused by changed design load and excessive amount of transportation. For these rural bridges, repairs and replacements are needed. Even though there have been attempt to estimate the safety of existing bridges deteriorated with major defects, those approaches must rely on the observable damage and subsequent decisions are made subjectively. To avoid the high cost of rehabilitation, the bridge rating must correctly represent the present load-carrying capacity. Rating engineers use a methods such as Allowable Stress Design (ASD), Load Factor Design (LFD), and Load Resistance Factor Design (LRFD) to evaluate the bridge load carrying capacity. In this paper, the load rating methods are introduced, and it is illustrated how to use the load test data from literature survey. Load test is conducted to the bridge that was built 30 years ago in rural area. From load test results, new maintenance method is suggested instead of the bridge replacement.

Effect of Density Variation of High Tenacity PET Interlace Yarn on the Physical Properties of Pack Style Shock Energy Absorber (고강력 PET Interlace Yarn 밀도변화가 Pack Style Shock Energy Absorber의 물성에 미치는 영향)

  • Cho, Jin Won;Kwon, Sang Jun;Choe, Jong Deok;Kim, Sang Tae;Ji, Byung Chul;Yang, Seong Baek;Yeum, Jeong Hyun
    • Textile Coloration and Finishing
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    • v.27 no.2
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    • pp.132-141
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    • 2015
  • Fall-arrest systems(maximum arrest force and allowable free-fall) have been widely applied to provide a safe stop during fall incidents for various industrial activities. Fabric structure affects on the mechanical properties of shock energy absorber. The object of this study is to perform the basic research for the evaluation of the capacity of fall arrest energy absorber in relation to the different interlace yarn density. In this work, pack style energy absorber was prepared by weaving 10 types(Interlace yarn density used high tenacity PET 1000D : 60, 59, 58, 57, 56, 55, 54, 53, 52, 51). The paper presents the results of theoretical investigations of the performance of adjustable absorber during fall arrest. Dynamic load tests based on the EU fall protection equipment standard(CE : EN355:2002) were conducted. Results showed that the maximum arrest force by dynamic load test of energy absorber was satisfied with global standard(below 6,000N). Also, Maximum allowable free-fall of energy absorber showed below 1.75m.

A Fatigue Stability Study of an Existing Bridge Due to Vehicle Load Direction Change (차량 하중 방향 변경에 의한 기존교량의 피로안정성 연구)

  • Yi, Gyu-Sei;Lee, Sung-Yol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.8
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    • pp.2062-2067
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    • 2009
  • During a construction of a road, a temporary bridge is often connected to a existing bridge. In this case, a fatigue stability problem, which was not considered in the design of the bridge, can be occurred in the main girder of the existing bridge due to the vehicle load direction change. In this study, the fatigue stability of the main girder and cantilever slab of the bridge was tested with the allowable fatigue stress of the design specifications of the road bridge. The big stress change was occurred at 55m away from the support, and the middle of the span. Furthermore, the excess of the allowable fatigue stress of the design specifications of the road bridge was confirmed at the cross section. The bridge after the reinforcement was tested for the fatigue stability, and it was confirmed that the bridge is safe.

Construction Safety Evaluation of Local Bearing Strength of Hollow Core Slab (중공 슬래브의 국부지압강도에 대한 시공안전성 평가)

  • Hur, Moo-Won;Yoon, Jeong-Hwan;Hwang, Kyu-Seok;Yoon, Sung-Ho;Park, Tae-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.2
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    • pp.8-15
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    • 2018
  • Hollow Core Slab is a very efficient system that can reduce weight and its use has increased. Void slab is a concrete slab that has voids substituted with void material. Because of its saved volume of concrete, void slab can reduce weight of slabs. Also, it can't only save concrete but also can reduce carbon-emission. However, because of the unclear bearing strength at the part of void substituted with voiding material, several problems occur in constructing field. In this study, void slab including void material was built and local bearing strength test was carried out for 3 types of load(truck load, support load and Jack support load). As a result, bearing strength of void neck and upper void material is more than allowable load. And also, bearing strength of specimens with using deck and not using deck are also over allowable loads.

Case Studies of Several Load Tests for Large Diameter Battered Steel Pipe Piles Constructed on the Offshore Area. (대구경 해상 강관말뚝의 설계지지력 확인을 위한 여러 가지 재하시험의 적용)

  • 이정학;서덕동;정헌주
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.291-298
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    • 2001
  • It is very difficult to accomplish load tests of piles with large diameter constructed on the offshore area, because of requirement for large scaled loading equipment and bad testing conditions. Therefore, so far in many cases pile driving dynamic formulas have applied to quality control, and recently dynamic load test method is widely used for confirming bearing capacities of such piles. However, in cases of piles with very large diameter about 2,500mm, it is nearly impossible for regular type load test methods of piles such as static and dynamic to apply owing to very large design load. This is case studies of load tests such as modified static and dynamic load tests of piles and point load tests of rock samples for estimating rational allowable bearing capacity of very large diameter piles constructed on the marine area.

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Failure Mode and Fracture Behavior Evaluation of Pipes with Local Wall Thinning Subjected to Bending Load (감육배관의 굽힘하중에 의한 손상모드와 파괴거동 평가)

  • Ahn, Seok-Hwan;Nam, Ki-Woo;Kim, Seon-Jin;Kim, Jin-Hwan;Kim, Hyun-Soo;Do, Jae-Yoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.1
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    • pp.8-17
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    • 2003
  • Fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear Power Plant. In Pipes of energy Plants, sometimes, the local wall thinning may result from severe erosion-corrosion (E/C) damage. However, the effects of local wall thinning on strength and fracture behaviors of piping system were not well studied. In this paper, the monotonic bending tests were performed of full-scale carbon steel pipes with local wall thinning. A monotonic bending load was applied to straight pipe specimens by four-point loading at ambient temperature without internal pressure. From the tests, fracture behaviors and fracture strength of locally thinned pipe were manifested systematically. The observed failure modes were divided into four types; ovalization. crack initiation/growth after ovalization, local buckling and crack initiation/growth after local buckling. Also, the strength and the allowable limit of piping system with local wall thinning were evaluated.