Drophead Formwork System Implications in Flat Plate Concrete Floor Construction

Abstract

This study analyzed aspects of shoring and reshoring of multi-story concrete construction using retractable dropheads for the temporary support of the flat plate floor slabs. A comparison was made between this method and the traditional method using removed shores. The objective was to determine the ability of the slabs to support construction loads at the stage of very early age removal of the forming panels. The strength evaluations were conducted considering punching shear, flexural strength, and beam shear. The results were presented as a series of charts showing the structural capacities of a slab for various slab depths and concrete compressive strengths attained. An analysis is also presented of the distribution of the construction loads throughout a structure using both the traditional method and the method with the retractable dropheads. An additional analysis was also done considering the effects of having various percentages of slab activation due to partial rather than full release of the shores.