Study On Finite Element Analysis And The Monitoring Of The Cuplok Steel Tubular Scaffolding In Cast-in-site Construction

With the development of the skew bridge, curved bridge, special-shaped bridge and overpass bridge structures, Cuplok steel tubular scaffolding because of the simple structure, flexible erection, high universality, relative low cost and some other reasons has been widely used in the construction. However, the deficiencies of design theory, the shortage of construction management and stuff quality are the main factors that induce structural instability during the construction phase. As a result, engendering template accidents happened frequently. Moreover, once the incident happened, it will lead to serious consequences that a lot of workers will be hurt or killed, and will bring the parties unforeseen economic losses. Therefore, the study on the safety of scaffold system and bearing framework system during the construction phase has the important theory and the practical significance.Based on previous researches of Cuplok steel tubular scaffolding support system and the grade separation construction project (Phase II) in the Xi'an Northeast two links, this paper monitored the stress of scaffold column during the fresh concrete placement phase. At the same time, it established bowl-buckle steel pipe support model through finite element analysis software MIDAS/Civil. Thereby, it reached some useful conclusions by comparing finite element analysis with theoretical calculation. Finally, we discussed the structural factors on the stability capacity of the Cuplok steel tubular scaffolding. The concrete work is as follows:1. First, this article elaborated the research status of the Cuplok steel tubular scaffolding at home and abroad, and then induced the support collapsing accident and the created loss in the recent years. At the same time, it pointed out the insufficiency of fundamental research about Cuplok steel tubular scaffolding. As a result, it was necessity to study on the stress analysis and the monitoring of the steel pipe support.2. This paper introduced the theory of structural stability and the form of unstable failure, and described two critical methods that the balance method and the energy method. And then it expounded in detail application of the finite element method in stability analysis of the scaffold, which established the theoretical foundation for the analysis.3. The author has completed a load test to the bowl-buckle framework system about the grade separation construction project (Phaseâ…¡) in the Xi'an Northeast two links, and has studied on the stress change rule during the fresh concrete placement phase, and has obtained the bearing and the distortion of the bars which keeped in the allowable scope, no abnormal situation, support to security.4. In the paper, the whole bowl-buckle steel pipe support model has been established for construction simulation by large finite element software MIDAS/Civil. After comparing the results and monitoring data which have confirmed the modeling reliability, they had the similar law.5. Finite models of Cuplok steel tubular scaffolding have been established by MIDAS/Civil software in the paper. The influence of some important factors which included extending distance of the top horizontal bar, sweep shot, vertical strut and so on have been analyzed.6. The results in the paper are valuable for design and erection research in the construction by Cuplok steel tubular scaffolding. It gives valuable reference for the application of Cuplok steel tubular scaffolding in cast-in-site construction, to ensure bridge quality and safe construction.