• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.11a
• /
• pp.25-26
• /
• 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.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.7
• /
• pp.679-683
• /
• 2016

Boilers of large-sized coal-fired power plants are being operated under very poor conditions such as continuous operation or repeating of start-up and shutdown for a stable supply of electricity. Thus periodic inspection and maintenance are required to ensure reliability of operation. The loads of existing scaffolding systems for the maintenance of boilers are concentrated in the lower parts structurally, which may cause a serial collapse of the overall scaffolding system when there are problems in some members. Therefore, in this study, a safe furnace scaffolding system is developed by dispersing the loads in the upper part, as well as minimizing the hazards of serial collapsing. In addition, for cases where the direct installation of furnace scaffolding is challenging owing to the structure of the boiler tube, a lifting system for the installation of furnace scaffolding is developed so that furnace scaffolding can be supported to secure the integrity of the power generating facility.

• Journal of the Society of Naval Architects of Korea
• /
• v.47 no.2
• /
• pp.233-241
• /
• 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.

• Journal of the Korean Society of Safety
• /
• v.38 no.3
• /
• pp.61-68
• /
• 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.

• Journal of the Society of Disaster Information
• /
• v.19 no.1
• /
• pp.128-137
• /
• 2023

Purpose: This study proposes a way to improve quality and increase safety by studying a method that allows the system scaffolding, which is partly used for high-altitude work at construction sites, to be applied to various types of structures in shipbuilding and plant industry sites. Method: A fact-finding survey was conducted targeting 8 companies, and a plan was established that reflected the opinions of the field survey and the practitioners and experts by analyzing the literature and the Internet survey. Result: Through analysis of related patents, FGI with companies, etc., we discovered the possibility of application expansion through research and development of materials that can be applied to various types and improvement plans for enhancing the professionalism of construction companies. Conclusion: System scaffolding has a high importance in terms of safety, but related research around the world is sluggish. Therefore, it will be possible to meet the demands for quality and safety by enhancing the software expertise and developing and researching user materials that can be applied to various types.

• Advances in concrete construction
• /
• v.4 no.3
• /
• pp.173-194
• /
• 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.

• Journal of architectural history
• /
• v.32 no.1
• /
• pp.7-20
• /
• 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
• /
• v.14 no.1
• /
• pp.75-108
• /
• 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.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.24 no.6
• /
• pp.389-395
• /
• 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.

• Journal of the Korean Society of Safety
• /
• v.35 no.5
• /
• pp.49-58
• /
• 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.