A Novel Optimised Inter-Locking Connection For Steel Modular Building Systems To Enable Re-Use

Abstract

Hot-rolled steel Modular Building Systems (MBS) represent the highest level of Off-Site Con-struction (OSC) in which prefabricated, and often prefinished steel modules are delivered to site on a ‘just-in-time’ basis and assembled into complete building systems. Besides the already well-known advantages such as tight tolerance control, reduced on-site human intervention and speedier construction times, the context of the ongoing climate emergency has brought forward the connection between circular economy (CE) and opportunities of steel MBS for disassembly and reuse. However, the use of hybrid structural systems, the functionality of inter-modular connections, and the effects of complex and demanding load transfer paths often question the actual prospects of deconstruction, repair, relocation, or reuse. So far, inter-module connections have been heavily influenced by conventional design methods, relying on bolts, welds or even prestressing strands, which require laborious on-site tasks and simplifying design assumptions, often raising uncertainty about structural behaviour of modular buildings. In an attempt to mitigate limitations of existing systems, a new inter-module connection was envisaged, inspired from the inter-locking method of joining. At the forefront of the develop-ment process, topology optimisation (TO) was adopted in the conceptual design of the main component of the joint, assisting the morphogenesis process which provided the final configu-ration of the novel system. The structural performance of the newly proposed connection was assessed through a series of static monotonic and quasi-static cyclic FE analyses. Results re-vealed that in terms of load-bearing capacity, ductility and energy dissipation ability, the struc-tural behaviour of the new connection was comparable to that of other inter-module joints in literature, while managing to tackle their limitations by introducing both an easy-to-install and easy-to-disassemble configuration with promising opportunities for reuse, further demonstrat-ing that inter-locking joints could be worthy competitors for traditional means of attachment in the future of modular construction.