Steel-timber composite structures with semi-rigid beam-to-column joints: Overview and perspectives towards a design for disassembly & reusability

Abstract

Composite structures, which combine two or more complementary materials, have long been utilized in the construction sector for their structural efficiency and economic benefits. Due to the latest advancements in timber manufacturing technology, use of timber in structural composite applications has gained popularity, given its environmental advantages in reducing the carbon footprint of the buildings. Particularly, Timber-Concrete Composite (TCC) structures have gained significant popularity over the past two decades. However, the use of steel in a composite framework with timber is a relatively new concept. Especially considering steel's greater ductility compared to the concrete, suitability for reuse, and its superior mechanical properties, steel-timber composite (STC) structures hold significant potential. While there are some studies on steel-timber flooring solutions, the majority focuses on the connections between steel beams and timber panels. Few works explore the advantages of moment beam-to-column joints in enhancing bending moment distribution and reducing deflections in STC beams. However, none of the configurations proposed in these studies fully integrate the disassembly and reusability concept. This study aims to provide an overview of existing configurations in the literature and evaluate their adaptability for the disassembly and reusability concept by offering a mechanical assessment of various solutions available in the literature. Initial assessments involved a comparative analysis of existing configurations. A collection of investigated STC beam-to-columns joints are evaluated for their mechanical behavior such as: rotational stiffness, rotation capacity, bending moment capacity, ductility and associated failure modes. Subsequently, an evaluation of existing solutions in terms of disassembly and reusability is conducted, leading to the identification of a future design need in this regard. Finally, a Finite Element Analysis (FEA) is conducted to further complement the analysis.