Proof of concept of a demountable steel‐concrete composite flooring system: Fid-Bau Portal

Proof of concept of a demountable steel‐concrete composite flooring system

Gîrbacea, Ioan Andrei / Nijgh, Martin Paul / Veljkovic, Milan

Environmental concerns steer the construction industry towards more sustainable developments such as demountable and reusable structures. Composite structures are a frequent solution for multi‐story buildings and bridges, however the use of welded shear connectors requires labour and energy intensive disassembly. Two bays of a demountable flooring system for a multi‐storey car park building were erected in the laboratory. The flooring system consists of large prefabricated concrete decks connected to tapered steel beams. The feasibility of assembly and disassembly of the flooring system was tested under laboratory condition. Shear interaction was achieved by an embedded bolt and coupler which are connected to the top flange of the steel beam by an external injection bolt. Oversized holes are used in the top flange of the steel beam to accommodate fabrication and execution deviations and the deformations occurring during construction. Extensive imperfection measurements and finite element models were used to design the oversized hole diameter to 32 mm. The hole clearance must be compensated either by pretensioning or injecting the bolt‐to‐hole clearance with an epoxy resin to enable instantaneous composite action under live loads. Experimental injection of 150 injection bolts confirms that epoxy resin can reliably fill the hole clearance, and that the injection process takes 30 seconds per bolt. Various non‐uniform shear connector arrangements were considered to minimize construction costs and maximize the speed of execution. The mechanical behaviour of the demountable composite beam was tested experimentally and numerically.