Design for Deconstruction for Sustainable Composite Steel-Concrete Floor Systems

Abstract

Conventional steel-concrete composite floor systems utilizing steel headed stud anchors and metal decks are cost-effective and widely used solutions for non-residential multi-story buildings, due in part to their enhanced strength and stiffness relative to non-composite systems. Because these systems use steel headed stud anchors welded onto steel flanges and encased in cast-in-place concrete slabs to achieve composite action, it is not possible to readily deconstruct and reuse the steel beams and concrete slabs. As the building industry is moving towards sustainability, there are clear needs for developing sustainable steelconcrete composite floor systems to facilitate material reuse, minimize consumption of raw materials, and reduce end-of-life building waste. This paper presents the behavior and design strategies for a sustainable steel-concrete composite floor system. In this system, deconstructable clamping connectors are utilized to attach precast concrete planks to steel beams to achieve composite action. The load-slip behavior of the clamping connectors was studied in pushout tests, and the test results showed that the clamping connectors possess similar shear strength to 19 mm diameter shear studs and much greater slip capacity. Four full-scale beam tests were performed to investigate the flexural behavior of the deconstructable composite beams under gravity loading and validate the connector behavior attained from the pushout tests. All the beams behaved in a ductile manner. The flexural strengths of the composite beam specimens closely match the strengths predicted for composite beams by the design provisions of the American Institute of Steel Construction (AISC).