Stability Considerations for Concrete Forming Support Systems

The contractual responsibilities of building designers are often limited to the performance of a structure after construction is complete. That is, the designers leave the means and methods of construction, including the stability of the partially completed structure, to the contractor. This can lead to problems, as contractors are likely not trained in structural stability and may not understand how seemingly minor alterations to components can have a disproportionate effect on the stability of the temporary works. This paper presents a case study that explores the stability of shoring systems used to support concrete formwork, and in particular the adverse effects of modifying component lengths and the addition of aluminum spacers. Classical calculations are performed and verified using OpenSees analyses to determine the expected change in capacity due to the adjustments. Finally, we offer advice to engineers and contractors warning of dangerous adjustments so they might avoid similar damage or collapse of forming support systems on their projects.

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