On analysis of HSQ steel beams combined with a CLT flooring system

Abstract: With the aspiration of modern-day society to achieve a more environmentally friendly andsustainable world, several industries of the world are continuously and constantly examiningdifferent possibilities to reduce the climate impact of the world. For the construction industry,this is no different. Due to the well-known environmental advantages of timber, the naturalprocedure is to investigate the possibilities to increase the use of timber in the currentconstruction industry. Different engineered timber products have seen a development in recentyears, these products have greater strength and capacity than ordinary timber. One of theseproducts is CLT (Cross laminated timber). The current construction industry is highlydeveloped with various documented and traditional structural designs. Thus, the objective ofthis thesis is to investigate the possibilities of using a CLT floor structure in a standardizedstructural design. More specifically, replacing a concrete slab with a CLT floor system in atraditional steel and concrete frame.The observed structure is modelled and consists of HSQ beams supported by steel columns,with several CLT slab elements laying on the bottom flanges of the HSQ beams. The thesisstrives to verifying that the structure has sufficient strength capacity and stability. This byinvestigating different connections in the floor structure and ensuring that the floor structure isstable regarding horizontal and vertical forces. Both the CLT slab and HSQ are designed, aswell as the connection between them with the objective that the connection and floor structurebeing continuous. The diaphragm action of the floor structure is investigated to secure that theshear flow due to external forces does not overly deform the structure. Different screws areused for the different connection, in which they are designed to have sufficient load carryingcapacity. All the various calculations are automated providing a calculation sheet for futurework. An optimization of the calculations is performed with the objective of reaching thelongest possible span of both the HSQ beam and CLT slab.The result of the analysis presents the maximum possible spans for both the HSQ beam andCLT slab. Continuity across the connection between the HSQ beam and CLT slab is achievedusing a LVL panel, which transfers the forces across the connection. The critical parametersthat restrict further optimizations of the HSQ and CLT spans, is the deflection of the HSQ beamand the tension strength capacity of the LVL panel. The shear deformation in the floor structuredid not constitute a critical parameter in the floor structure.