• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.25-26
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• 2021

System scaffolding and shoring are temporary structures in which vertical members, horizontal members, bracing members and trusses are assembled and installed. In order to ensure quality and safety, the quality test shall be carried out in accordance with the Guidelines for Quality Management of Construction Works (MOLIT Notice No. 2020-750). The quality test method (national standard) for Components for tied post system scaffolding and shoring is based on the Korean standards (KS F 8021) and the Safety certification standards (MOEL Notice No. 2021-22). However, the two standards differ in some aspects such as performance standards and etc, so cause confusion when applying them on-site. In addition, the standard for truss are applied only to trusses for shoring and cannot be applied to trusses for scaffolding. Therefore, this study aims to unify the two national standards and establish realistic standards.

• 대한기계학회논문집A
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• 제40권7호
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• pp.679-683
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• 2016

대형 석탄 화력발전소의 보일러는 안정적인 전력량 수급을 위하여, 계속적인 운전 혹은 기동 정지가 반복하면서 운전 되는 등 매우 열악한 상태에서 운전되고 있기 때문에 신뢰성을 유지하기 위한 주기적 점검과 정비는 필수적이다. 정비를 위한 기존의 비계시스템은 모든 하중이 하부로 집중되어 일부 부재에 문제 발생시 연쇄적으로 비계 시스템이 붕괴되는 문제점이 있다. 이에 따라 본 연구에서는 새로운 노내비계를 개발하여 상부에서 하중을 분산시키고, 일부 부재에 문제가 발생하더라도 연쇄 붕괴의 위험을 최소화하였다. 또한, 보일러 튜브의 구조로 인하여 직접적인 설치가 어려운 경우 노내비계의 설치를 위한 인양시스템을 개발하여 노내비계의 구조적인 안정성을 향상시키고 비계 작업자의 안전성을 확보하여 발전설비의 건전성을 확보할 수 있었다.

• 대한조선학회논문집
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• 제47권2호
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• pp.233-241
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• 2010

Scaffolding system in the membrane LNG carrier is a steel structure composed of various pipe-shaped members connected by specific coupling devices. In this study, the automatic design program for scaffolding system in membrane LNG carrier has been developed. It enables user to arrange members easily considering design constraints and input variables such as size of tank, position of legs, level height and so on. In addition to that, it creates finite element analysis model with loading and boundary conditions automatically and carries out structural analysis. With post processor based a state-of-the-art computer graphics, users can easily check the results of structural analysis and make a report for structural safety of scaffolding system.

• 한국안전학회지
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• 제38권3호
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• pp.61-68
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• 2023

This study performed a structural performance evaluation of a system scaffolding for elevator installation work developed in previous studies. The structural performance was evaluated via a structural test conducted to apply the working load specified in the design standard. The deflection of the horizontal member and the stress of each member constituting the system scaffolding were measured. Consequently, the structural safety evaluation including structural behavior and required performance was performed using the deflection and stresses measured from the structural test. The structural test and safety evaluation results based on the heavy working load corresponding to the design load indicated that the deflection, which is the performance criterion of the horizontal member, did not exceed the allowable value. Further, each member's stress, which is a safety evaluation indicator, did not exceed the allowable strength for both horizontal and vertical members with bending behavior and fordable bracing with tensile behavior, while also satisfying the required safety factor. In addition, the results confirmed the safety against deformation, partial damage, and destruction owing to excessive and maximum load. Therefore, the system scaffolding developed in this study satisfies both the structural performance and safety required by the design standards; thus, it can be applied to elevator installation work sites.

• 한국재난정보학회 논문집
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• 제19권1호
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• pp.128-137
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• 2023

연구목적: 건설 현장에서 고소 작업시 일부 사용하고 있는 시스템비계를 선박건조 및 플랜트 산업현장의 다양한 형태의 구조물에 확대 적용이 가능토록 방법을 연구하여 품질향상과 안전성을 높이는 방안을 제시하고자 한다. 연구방법: 8개 기업을 대상으로 실태조사를 실시하였으며, 문헌이나 인터넷 조사등을 분석하여 직접 현장조사와 실무자, 전문가의 의견을 반영한 방안을 수립하였다. 연구결과: 관련 특허 분석, 업체와의 FGI 등을 통한 분석하고 시공업체의 전문성 제고를 위한 개선 방안과 다양한 형태에도 적용이 가능한 자재의 연구 개발을 통한 적용 확대의 가능성을 발견하였다 결론:시스템비계는 안전측면으로 그 중요성이 높으나 전 세계적으로 관련 연구는 부진한 편이다. 이에 software적인 전문성 제고와 다양한 형태에도 적용이 가능한 사용자재의 개발연구로 품질 및 안전에 대한 요구를 충족할 수 있을 것이다.

• Advances in concrete construction
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• 제4권3호
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• pp.173-194
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• 2016

This paper consists in a study of a new contructive sequence of road viaducts with Movable Scaffolding System (MSS) using numerical tools based on finite element method (FEM). Traditional and new sequences are being used in Spain to build viaducts with MSS. The new sequence permits an easier construction of one span per week but implies some other issues related to the need of two prestressing stages per span. In order to improve the efficiency of the new sequence by reducing the number of prestressing stages per span, two solutions are suggested in this study. Results show that the best solution is to introduce the 100% of the prestressing force at the self-supporting core in order to improve the road viaduct construction with movable scaffolding system by reducing execution time without increasing economic costs.

• 건축역사연구
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• 제32권1호
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• pp.7-20
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• 2023

The construction method of scaffolding structures is different from Mortise and Tenon and bucket arch structure of traditional large woodwork. It forms an independent construction system-fixing nodes with knots, a large number of diagonal braces are used to fix shelves and the structures mostly contain X-shape and triangular shape details. Simple ones include stalls, sheds, rain sheds, altars, lamp racks etc. But the scaffolding with larger scale and more complicated structure are modeled on archways, theatres and other buildings which are used in commercial and festival activities. At present, Macao, Hong Kong, Guangdong, Sichuan, Shanxi and other places in China have retained the custom of using scaffolding structures in important festival activities, but their uses, techniques and building types are slightly different from place to place. Due to building and demolishing at any time, the construction and service cycle is short. As a result, there are almost no physical objects left. We can only deduce the use and technical characteristics of ancient scaffolding skills through the colorful building styles that have been preserved with folk activities in various parts of China, the craftsmanship handed down from generation to generation by the scaffolding guild and artisans, and the description of cultural and historical materials and the mutual corroboration of visual materials.

• Educational Technology International
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• 제14권1호
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• pp.75-108
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• 2013

The purpose of this study is to find a way to improve digital textbooks for self-regulated learning by applying cognitive scaffolding designs to an elementary math digital textbook and examining the effectiveness of the system. Hence this study was conducted in two steps. First, a framework for scaffolding design was devised by examining the problems and difficulties students encounter when using a mathematics digital textbook. Second, after the digital textbook was revised by applying the scaffolding design frameworks, the effectiveness of the scaffolding framework was examined by comparing students' achievement levels in an experimental group and that of students in a control group. Seventy fifth-graders participated in this study. Students were divided into two groups: an experimental group and a control group. The students in the experimental group studied with the revised version of the digital textbook and the students in the control group studied with the original version of the digital textbook. The students received a pretest before the experiment. After the experiment, they took an achievement test and completed a usability questionnaire. The data were analyzed by ANCOVA with the SPSS Windows version. The results revealed that the students who used the revised program (to which design strategies for scaffolding were applied) showed higher levels of achievement than those who used the original version. In addition, students in the experimental group generally showed higher scores on the usability survey, which consisted of four sub-categories such as 'effectiveness', 'efficiency', 'satisfaction', and 'learnability'. There was a statistically significant effect on 'efficiency'. These results implied that scaffolding strategies were effective for mathematics learning through the use of an elementary digital textbook.

• 전력전자학회논문지
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• 제24권6호
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• pp.389-395
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• 2019

This paper presents the sensorless position control of an auxiliary scaffolding step system for vehicles using DC motors. The designed auxiliary scaffolding step has a mechanical protector at the stop position. At this position, the scaffolding is forcibly stopped by the mechanical protector, and the motor current is dramatically increased to the stall current of the DC motor, thereby increasing the electrical damage. In this study, the estimated back EMF- and current model-based observers are proposed to estimate the motor speed and stop position. A simple V/F acceleration voltage pattern is used to operate the auxiliary scaffolding system. The estimated moving position is adopted to determine the stop position of the DC motor with the load current state. The operating current of the DC motor can be reduced by the estimated moving position and V/F acceleration pattern. At the stop position, the proposed sensorless position controller can smoothly stop the DC motor with the estimated moving position and reduced load current without any mechanical and electrical stress from the stall current from the mechanical protector. The proposed control scheme is verified by the comparison of simulations and experiments.

• 한국안전학회지
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• 제35권5호
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• pp.49-58
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• 2020

In domestic construction sites, when installing steel pipe scaffolding and system scaffolding, the guardrails are installed after the installation of the work platforms. This conventional guardrail system (CGS) is always exposed to the risk of falls because the safety railing is installed later. In order to prevent fall disasters during erecting and dismantling scaffolds, it is necessary to introduce the advanced guardrail system (AGS) which installs railings in advance of climbing onto a work platform. For the introduction of the AGS, the structural performance of the system scaffolding applying the CGS and the AGS was compared and evaluated. The structural analysis of the system scaffold (height: 31 m and width: 27.4 m) with AGS confirmed that structural safety was ensured because the maximum stress of each element of the system scaffolding satisfies the allowable stress of each element. As a result of performance comparison of CGS and AGS for each element, the combined stress ratio of vertical posts in AGS was 6.4% lower than that of CGS. In addition, in the case of ledger and transom, the combined stress ratios of AGS and CGS were almost the same. The compression test of the assembled system scaffolding (three-storied, 1 bay) showed that the AGS had better performance than the CGS by 9.7% (8.91 kN). The cross bracing exceeds the limit on slenderness ratio of codes for structural steel design. But the safety factor for the compressive load of the cross bracing was evaluated as meeting the design criteria by securing 3 or more. In actual experiments, it was confirmed that brace buckling did not occur even though the overall scaffold was buckled. Therefore, in the case of temporary structures, it was proposed to revise the standards for limiting on slenderness ratio of secondary or auxiliary elements to recommendations. This study can be used as basic data for the introduction of AGS for installing guardrails in advance at domestic construction sites.