Structural instability of multi-storey door-type modular steel scaffolds
Section snippets
Modular steel scaffolds as temporary structures
Modular steel scaffolds are temporary structures and they are commonly used as supporting scaffolds in construction. The modular units are typically fabricated from slender members made from high strength cold-formed steel tubes. It should be noted that these scaffolds have been widely used in Hong Kong, Japan, Korea, Singapore, Taiwan, United Kingdom and United States for many years, and they are easy to fabricate, install and dismantle. However, structural failure of these scaffolds often
Structural behaviour of modular steel scaffolds
Modular steel scaffolds are slender structures highly susceptible to instability, and both out-of-plane and in-plane buckling of the scaffolds are possible, depending on steel grades, member configurations and dimensions, loading conditions, and boundary conditions. In bridge construction where falsework of high-clearance was required, tubular steel scaffolding systems with metal couplers were commonly employed. The structural behaviour of these high-clearance scaffolds have been investigated
Objectives and scope of investigation
This paper presents an extensive study on the structural behaviour of multi-storey door-type modular steel scaffolds through both experimental and numerical investigations. The objectives of the study are:
- (a)
To understand the structural behaviour of multi-storey door-type modular steel scaffolds through experimental and numerical investigations.
- (b)
To examine the effects of both positional and rotational restraints on the load carrying capacities of these scaffolds.
- (c)
To identify important factors which
Experimental investigation
In order to examine the structural behaviour of modular steel scaffolds, six full-scale tests were executed in order to establish their load carrying capacities against column buckling. Fig. 2 illustrates the member configurations of the door-type modular steel scaffolds together with their dimensions. Three one-storey one-bay modular steel scaffolds (MSS1) with similar geometrical dimensions were tested, and each of the test specimens comprised of two 1930×1219 mm steel scaffolds which were
Numerical investigation
Owing to the high slenderness of column members, and the complicated member configurations in these scaffolds, significant deformations often occur before or at the onset of buckling. In order to predict the structural behaviour, and hence, the load deformation characteristics of these scaffolds up to maximum applied loads, non-linear analysis is required. In the present study, an advanced non-linear analysis software NIDA using one-element-per-member formulation is employed [13] to evaluate
Practical considerations
The following practical aspects on the design and construction of modular steel scaffolds should be fully incorporated for their safe and effective use in practice:
Conclusions
This paper presents an extensive study on the structural behaviour of multi-storey door-type modular steel scaffolds through both experimental and numerical investigations. It is demonstrated that
- (a)
The strength utilisation ratios of two-storey and three-storey modular steel scaffolds are only 85 and 80% of those of one-storey scaffolds respectively. Consequently, it is unconservative to take the load carrying capacities of two-storey and three-storey modular steel scaffolds to be the same as
Acknowledgements
The research project leading to the publication of this paper is supported by the Research Committee of the Hong Kong Polytechnic University (Research Project No. G-V849).
References (18)
- et al.
High clearance scaffold systems during construction—I. Structural modeling and modes of failure
Eng Struct
(1996) - et al.
Experimental and analytical capacity of frame scaffolding
Eng Struct
(2001) - et al.
On the development of a robust element for second-order ‘Non-linear integrated design and analysis (NIDA)’
J Construct Steel Res
(1998) - et al.
The collapse strength of tubular steel scaffold assemblies
Proc Inst Civil Eng
(1977) - et al.
Structural behaviour of load bearing falsework
Proc Inst Civil Eng
(1979) - et al.
Load carrying capacity of scaffolds
Struct Eng Int
(1995) - et al.
Sway stiffness of scaffold structures
Struct Eng
(1997) - et al.
Load-carrying capacities and failure modes of scaffold-shoring systems, Part I: Modeling and experiments
Struct Eng Mech
(2000) - et al.
Load-carrying capacities and failure modes of scaffold-shoring systems, Part II: An analytical model and its closed-form solution
Struct Eng Mech
(2000)
Cited by (68)
A numerical study on rotational stiffness characteristics of the disk lock joint
2023, Journal of Constructional Steel ResearchProbabilistic analysis of derrick frame in a formwork support system
2023, Ain Shams Engineering JournalExperimental study on mechanical properties of steel tube-coupler connections in corroded scaffolds
2021, Journal of Constructional Steel ResearchCitation Excerpt :The loading details and experimental setup are shown in Fig. 5. The slipping stiffness or resistance primarily affects the load transfer from the horizontal tubes to the vertical ones in steel tube-coupler scaffolds, while the lateral rigidity and overall buckling properties of steel tube-coupler scaffolds are determined by the rotational stiffness of the right-angle coupler connections [26,27]. Hence, experimental studies were performed to explore the torsional behavior of the right-angle coupler connections.
Lateral stability of slender cold-rolled hollow tubular sections with initial imperfections
2020, Engineering StructuresCitation Excerpt :In his article, Robert G. Beale [16] proposed a review of the research on scaffolding and defective work structures carried out over the last forty years. Most of these studies [17–19] dealt with suitable methods and analysis models used to determine the critical loads on scaffolding structures. Robert G. Beale [16] devoted part of his article to the design procedure for scaffolding.
Rigidity and safety optimization of 3-dimensional repetitive frame systems as bar-joint building with graphs
2019, Engineering StructuresStability analysis of different types of steel scaffolds
2017, Engineering StructuresCitation Excerpt :The numerical results of the elastic buckling analysis were higher than the values of the experimental tests with difference between 6% and 17%. Similar studies were carried out by Yu et al. [5,9] and Chung et al. [10], but for a analyzing the behavior of multi-story prefabricated scaffolding. The novelty of the study is that the finite element analysis has been performed taking into account different types of connections between floors.