• Earthquakes and Structures
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• 제25권5호
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• pp.307-323
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• 2023

This study compares two prominent design provisions, National Design Specification (NDS) and Eurocode 5, on load-carrying capacity calculations and failure analysis for mortise-tenon joints. Design procedures of double-shear connection from both provisions were used to calculate load-carrying capacity of mortise-tenon joints with eight different bolt sizes. From this calculation, the result was validated using finite element analysis and failure criteria models. Although both provisions share similar failure modes, their distinct calculation methods significantly influence the design load-carrying capacity values. Notably, Eurocode 5 predicts a 6% higher design load-carrying capacity for mortise-tenon joints with varying bolt diameters under horizontal loads and 14% higher under vertical loads compared to NDS. However, the results from failure criteria models indicate that NDS closely aligns with the actual load-carrying capacity. This indicates that Eurocode 5 presents a less conservative design and potentially requires fewer fasteners in the final timber connection design. This evaluation initiates the potential for the development of a wider range of timber connections, including mortise-tenon joints with wooden pegs.

• 한국산학기술학회논문지
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• 제20권10호
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• pp.468-477
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• 2019

다양한 재료와 신기술의 개발로 방수공사 시공방법이 변화되고 현장에 적용되고 있으나, 공사비산정기준은 현장실태를 제대로 반영하지 못하고 있다. 본 연구에서는 공사비산정기준을 개정하기 위해 시방기준분석과 현장실태 조사를 통한 주요개정내용 및 결과를 분석하였다. 먼저 현재 공사비산정기준에서 정하는 각 항목들을 분석하여 현장조사를 통한 실태와 비교 분석하였다. 주요 조사 내용으로는 현장의 바탕면 품질수준 향상으로 바탕처리 난이도가 감소하였으며, 재료의 기능향상으로 시공시간 단축과 다양한 시공방 법이 적용되고 있었다. 또한, 두 가지 이상의 재료를 복합적으로 사용하는 복합방수공법의 적용이 늘어나고 있었으며, 시공장소, 부위에 따라 생산성의 차이가 나타나는 것으로 분석되었다. 이 결과를 바탕으로 방수항목을 세분화하여 복합공법에 적용이 가능하도록 하였으며, 재료별, 시공방법별 투입 품을 차별화 하였다. 시공부위에 따라 구분된 기준을 제시하며, 적용성이 떨어지는 항목은 삭제하여 시방기준에 적합하고 현장시공실태를 반영한 개정으로 공사비산정기준의 적정성이 확보되었다. 향후 시방기준과 현장의실태의 변화에 유연하게 대응할 수 있는 세부화된 공사비산정기준 마련이 필요하다.

• 한국공간구조학회논문집
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• 제17권1호
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• pp.69-75
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• 2017

In fire design for floors, the three criteria of stability, integrity and insulation are required for the specified fire resistance duration. Among these, stability is not easy to confirm. For solid prestressed concrete slabs of uniform thickness, Eurocode 2 provides tabulated data and specifies an axis distance to the centroid of strands to achieve particular fire resistance ratings, but it is not clear if this data can be used for a wide range of different prestressed slab profiles. In order to verify the current code-fire ratings for precast prestressed slabs, both simple and advanced calculation methods are investigated. This paper examines the use of calculation methods, accounting for the real behaviour of unprotected simply supported prestressed concrete slabs exposed to the standard ISO 834 fire. The calculated fire resistance of each prestressed concrete slab is compared with tabulated data in Eurocode part 1.2, with detailed discussion.

• 대한간호
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• 제37권3호
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• pp.78-91
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• 1998

This descriptive study was conducted in order to develop a standard criteria for nursing laboratory facilities and equipment for use by the 3 year nursing colleges. The data was collected from Aug. 28 to Sept. 30, 1997 by mail from 44 3 year nursing schools. To develop a standard criteria, the syllabi for Fundamentals of Nursing laboratory and for Physical Assessment were collected and analyzed. The following information was elicited and analyzed by the researchers : 1. for each procedure in the syllabus, the percentage of schools using the procedures 2. the facilities and equipment recognized as necessary and the percentage of schools which possess each item 3. calculation of the standard criteria for size of the nursing laboratory together with a list of the necessary facilities and equipment. The results of the study were as follows : 1. The Size of facility was 181.2m2 for fundamentals of Nursing laboratory and 56.4m2 for the storage room. For those whose number of students exceed 120, 1.98m2 is required for each students. 2. The number of items included in the standard criteria was 92 for Fundamentals of Nursing and Physical Assessment and 47 for other nursing subjects. The items made of rubber, plastic and the disposable ones were suggested but excluded from the standard criteria. Based on the above findings, the following suggestions were made : 1. Periodic review of the standard criteria is necessary to update the standard. 2. A study on the standardization of the curriculum for basic science laboratory, including experiment and a standard criteria of equipment, is necessary. 3. A study to develop a computer program for management of nursing laboratory facilities and equipment is needed.

• 해양환경안전학회지
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• 제16권1호
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• pp.107-113
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• 2010

국내 주요 무역항에서는 예선운영 및 업무처리요령에 근거하여 지방해양항만청장이 예선의 사용기준을 정하여 운영하고 있다. 그러나 예선의 사용기준 및 소요마력에 대한 산출 방식이 각 항만마다 상이하고, 일부 항만의 경우 예선 사용마력에 대한 사용척수와 총 사용마력이 달라 예선 운용에 혼선이 예상된다. 본 연구에서는 국내 주요 무역항의 예선 사용기준을 상호 비교하여 문제점을 도출하고, 예선의 총 소요마력 산출 근거를 기초로 선박규모별 예선 사용에 대한 일원화된 기준을 제안하였다. 또한, 현행 예선사용기준은 풍속이 10m/s 미만인 통상적인 경우에 해당되므로 갑작스런 돌풍 및 태풍 등으로 인한 재난대비 차원에서 그 이상의 풍속에 대한 기준도 제시하여 예선 운영세칙에 포함할 젓을 제안하였다.

• 한국폐기물자원순환학회지
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• 제35권7호
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• pp.660-669
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• 2018

Domestic automotive shredder residue (ASR) recycling facilities must comply with 60% of the energy recovery criteria calculated by the waste control act, based on resource circulation of electrical and electronic equipment and vehicles. The method of calculating energy recovery criteria was newly enacted on November 6, 2017, and it has been judged that it is necessary to consider applicability. In this study, the energy recovery efficiency of 7 units was calculated by past and present calculation methods. Furthermore, this study attempts to find applicability and a method of increasing the energy recovery efficiency by taking advantage of available potentials. An analysis of the calculation results showed that the average values calculated by past methods, present methods, and the method that includes available potentials are 76.35%, 70.68%, and 78.24%, respectively. Therefore, the new calculation method for energy recovery efficiency is also applicable to domestic automotive shredder residue recycling facilities.

• 한국압력기기공학회 논문집
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• 제17권1호
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• pp.36-48
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• 2021

As the material aging of nuclear power plants has been progressing in domestic and overseas, crack growth becomes one of the most important issues. In this respect, the crack growth assessment has been considered an essential part of structural integrity. The crack growth assessment for nuclear power plants has been generally performed based on ASME B&PV Code, Sec. XI but the idealization of crack shape and the conservative solutions of stress intensity factor (SIF) are used. Although finite element analysis (FEA) based on iterative crack growth analysis is considered as an alternative method to simulate crack growth, there are yet no guidelines to model the crack-tip spider-web mesh for such analysis. In this study, effects of various meshing factors on FE SIF calculation are systematically examined. Based on FEA results, proper criteria for spider-web mesh in crack-tip are suggested. The validation of SIF calculation method through mapping initial stress field is investigated to consider initial residual stress on crack growth. The iterative crack-tip modeling program to simulate crack growth is developed using the proposed criteria for spider-web mesh design. The SIF results from the developed program are validated by comparing with those from technical reports of other institutes.

• 한국환경과학회지
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• 제20권10호
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• pp.1285-1295
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• 2011

In this study, occurrence status of nonpoint pollutants and characteristics of discharge by each nonpoint pollutants were examined through monitoring on nonpoint pollutants caused when raining in vineyard belonging to the agricultural area of various land use patterns. Also, the first flush analysis limited to studies on the existing non-percolation area was applied to percolation area to ascertain availability and criteria of study. Various water quality and sluice of nonpoint pollutants were analyzed, based on which discharge of nonpoint pollutants in agricultural area was ascertained to be influenced greatly by artificial factors such as period, cultivation, management, etc. Meanwhile, the first flush phenomenon at agricultural area was ascertained to occur, and the first flush was quantified through calculation of the first flush ratio. If MFF30 is based, discharge load by each nonpoint pollutants caused when raining was investigated to include 40.8% on the basis of total discharge. In case of SS in pollutants showed the highest first flush phenomenon of 64.8%. Through such a result, calculation possibility of the initial rain criteria was ascertained, and it was determined that reliability-assured criteria were calculated through further monitoring.

• 한국안전학회지
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• 제33권2호
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• pp.68-75
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• 2018

The safety management cost system under the Construction Technology Promotion Act has contributed greatly to the prevention of construction accidents according to the chronological changes and social demand, but various problems have been pointed out. The biggest problem is that the safety management cost is earmarked very low because other items of safety management costs except for the safety inspection are not appropriately included in the actual construction site. Furthermore, it has been pointed out that it is difficult to settle the orderer due to the lack of specific use criteria. Therefore, in order to secure the proper safety management cost, this study is to estimate the actual cost by using of specification, quantity, material cost, labor cost for each type of the safety management item The results of this study were compared with the 71 cases of safety management costs in the safety management plan. In addition, analysis of unclear or unnecessary items in the current safety management cost and criteria and suggestions for improvement are provided. It is hoped that the results of this study will contribute to the rational safety management rate calculation.

• 소음진동
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• 제6권3호
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• pp.363-373
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• 1996

In the case of a precision equipment, it requires a vibration free environment to provide its proper function. Especially, lithography and inspection devices, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved giga class semiconductor wafers. This high technology equipments require very strict environmental vibration standard in promotion to the accuracy of the manufacturing, inspecting devices. The vibration criteria are usually obtained either by the real vibration exciting test on the equipment or by the analytical calculation. The former is accurate but requires a great deal of time and efforts while the latter lacks reliability. This paper proposes a new method to solve this problem at a time. The permissible vibration level to a precision equipment can be easily obtained by analyzing the process of Frequency Response Function(FRF). This paper also demonstrates its effectiveness by applying the proposed method to finding the permissible vibration criteria of a Computer Hard Disk Drive.