CLT-Steel Composite Floors for Sustainable Multi-Storey Construction

This thesis encompasses the investigation of a novel proposed construction system that pairs Cross-Laminated Timber (CLT) floor panels with steel-frame multi-storey construction. As a substitute for concrete floors, the promise of CLT lies in its reduced embodied carbon, and its lightness, which gives the promise of reduced material usage and a reduction in the environmental impact of a multi-storey building overall. In addition to clarifying the environmental benefit such a system provides, this thesis seeks to determine whether forming composite sections from the CLT panels and the steel beam, can lead to meaningful enhancements to the section stiffness in bending. Finite element analysis is applied for this task, necessitating first a methodology for modelling CLT to capture its relevant complexities as a material, and subsequently incorporation of the behaviour of the joints between structural elements in the proposed system, with the key characteristics of the materials and joint models validated against physical test data. Focusing predominantly on a slimfloor arrangement of panels and beams, the study provides the first evaluation of the effective width of CLT floor panels when acting compositely with steel beams, provides a prediction for composite action CLT panels and Asymmetric Steel Beams (ASBs) with a series of connectors, and identifies areas of development within the system that could bring about increased composite benefits. The outcomes of the study are that in a slimfloor arrangement with contemporary panels, beams and connectors, the composite enhancement is small but measurable, and that with changes and development to the system components, much larger composite enhancement effects could be generated.