• Steel and Composite Structures
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• v.49 no.2
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• pp.143-159
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• 2023

Recently, the design of scaffolding systems has garnered considerable attention due to the increasing number of scaffold collapses. These incidents arise from the underestimation of imposed loads and the site-specific conditions that restrict the application of lateral restraints in scaffold assemblies. The present study is committed to augmenting the buckling resistance of vertical support members, obviating the need for supplementary lateral restraints. To achieve this objective, experimental and computational analyses were performed to assess the axial load buckling capacity of steel props, composed of two hollow steel pipes that slide into each other for a certain length. Three full-scale steel props with various geometric properties were tested to construct and validate the analytical models. The total unsupported length of the steel props is 6 m, while three pins were installed to tighten the outer and inner pipes in the distance they overlapped. Finite Element (FE) modeling is carried out for the three steel props, and the developed models were verified using the experimental results. Also, theoretical analysis is utilized to verify the FE analysis. Using the FE-verified models, a parametric study is conducted to evaluate the effect of different inserted pipe lengths on the steel props' axial load capacity and lateral displacement. Based on the results, the typical failure mode for the studied steel props is global elastic buckling. Also, the prop's elastic buckling strength is sensitive to the inserted length of the smaller pipe. A threshold of minimum inserted length is one-third of the total length, after which the buckling strength increases. The present study offers a prop with enhanced buckling resistance and introduces an equation for calculating an equivalent effective length factor (k), which can be seamlessly incorporated into Euler's buckling equation, thereby facilitating the determination of the buckling capacity of the enhanced props and providing a pragmatic engineering solution.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.301-311
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• 2012

The law(construction standard specification, construction, standard-work regulation, Industry safety standard related regulation) related to the installation of scaffolding being used commonly on the construction site is regulated that the gap of ledger is within 1.5m and first ledger is within 2m. The gap of ledger here is essential for the stability of scaffolding structure. But it is determined that it is possible for the gap of ledger is applied by explaining safety handrail as ledger, because of the fact that in current, on the construction site, safety handrail is installed with the material of scaffolding ledger as a steel tube pipe. On this study, it is aimed to guarantee the safety by analyzing the ledger of scaffolding practically and prevent the accident of manager and laborer through the actualization.

• Journal of the Korean Society of Safety
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• v.25 no.1
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• pp.57-61
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• 2010

Formwork is a temporary structure that supports its weight and that of fresh concrete as well as construction live loads. Scaffoling is a temporary frame used to support people and material in the construction or repair of buildings and other large structures. It is usually a modular system of metal pipes, although it can be made out of other materials. Bamboo is still used in some Asian countries like China. The purpose of a working scaffold is to provide a safe place of work with safe access suitable for the work being done. In construction site, steel pipes are usually used as scaffolds. In this study, scaffolding systems which is changed according to sleeper and joist space were measured by buckling test. Buckling load of respective scaffolding system was analyzed by structural analysis program(MIDAS). Buckling load of scaffold with/without wall connection and footboard was got by test and structural analysis. According to these results，we know that scaffolding system of case 3 is suitable. Buckling load of scaffold with wall connection is higher than without wall connection. So wall connection is important in scaffoling systems. Footboard in the scaffolding systems is not effective against promotion of buckling load. Finally, the present study results will be used to design scaffolding systems safely in the construction sites.

• Journal of Korean Society of Disaster and Security
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• v.12 no.3
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• pp.59-67
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• 2019

In this study, the UAV (Unmammed Aerial Vehicle) was applied for the photogrammetry of the construction site and the safety management of steel pipe scaffold. The research site is a temporary facility for building reinforcement on Samcheok Campus of Kangwon National University. The installation condition of the steel pipe scaffold was investigated, and the pillar distance, the beam distance and the wale distance were surveyed. As a result, it was found that the beam distance of the scaffold in the longitudinal direction was in good agreement with the standard, but the pillar distance and the wale distance were found to be less than the standard. Three-dimensional data can be used in drone shooting to enable three-dimensional measurement, so that it is possible to measure facilities hidden or located inside other facilities. Through the drone shooting, the condition of the site can be quickly recorded and the surveying can be carried out without interfering with the work of the field personnel. Although the installation of the temporary structure must be strictly observed to ensure the safety of the workers, it is found that the installation standards are still neglected in the field. In order to prevent this practice, it was thought that the legal system should be supplemented so that it could be checked periodically by using UAV in the field process management.

• Journal of the Korean Society of Safety
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• v.28 no.4
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• pp.66-71
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• 2013

There is a critically structural problem of scaffolding system when one of scaffold columns is remove to be used as a gangway for their temporary office in the structure before finishing all such as an apartment or office building. This is not used to checking to structurally checking at a construction site. This study is to find out which system at a site will be more effective and low-cost-high effectiveness of aluminum ladder, timber ladder, ${\phi}$1/2 inch steel pipe truss with a type of concave, convex warren truss ladders. Theses are structurally tested with horizontal set as a truss type with 1.8 meter long. Concentrated load has been loaded at the upper center of the system and checked its strain at the bottom center, using aluminum-use strain gage and steel-use gauge have been attached concave warren truss with diameter 1/2 inch has 14% stronger than convex truss. Convex truss has almost same strength as an aluminum ladder truss, it is found out.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.450-451
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• 2006

The method of conductor wiring is that a messenger wire is installed, the end of the wire is connected to the conductor and a engine puller pulls the conductor. The length of one section of wiring is $3{\sim}5km$ and one group messenger wire pulls simultaneously $2{\sim}4$ group conductor, while a tensioner maintains wiring tension to prevent the deflection of the conductor. However, there are many obstacles such as roads, power lines, communication lines, buildings, farms and crops. Therefore to prevent damage from conductor deflection a staging is used. The currently used staging is scaffolding lumber which is difficult to secure and it's construction efficiency is very low because it requires a lot of time and manpower. So this study developed a insulating defense tube and pipe connecting device, and a truss structure fabrication module using steel pipe which reduces construction time and cost through a compressive and dielectric strength test.

• Journal of the Korean Society of Safety
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• v.35 no.5
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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.

• Journal of the Korea Safety Management & Science
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• v.22 no.3
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• pp.1-8
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• 2020

The desulfurizers facility is cylindrical shape. To operate properly it needs nozzles cleaned, get rid of lime adhesion and sludge, repair the wear and corrosion of facility regularly. For this purpose, workers shall access the ceiling or vertical wall at high place. Ordinary scaffoldings such as steel pipe scaffolding or system scaffolding have been using so that workers can access them. With these ordinary scaffoldings, openings around cylindrical wall are inevitable which make workers can expose always to the risk of falling. The purpose of this study is to develop customized scaffolding to minimize the openings to prevent workers form falling during maintenance it. It consists of a hexagonal central tower and six trapezoidal outer towers. And the bracing among the towers have connected each other for self-standing and for maintaining the structure of towers. Span decks, the circumference footstools, steps, etc. are laid on each floor. The safety is reviewed by structural analysis and performance test. With this study, openings each floor of this scaffold are removed. The gap between the cylindrical wall and the edge of the work stage is approximately 100 mm. Therefore, we expect that workers can work safely and efficiently.