Demountable and resilient inter-module connection system with replaceable structural fuses for hot-rolled steel modular building systems (MBS)

A project by Dan-Adrian Corfar

Project summary

FORWARD IS MODULAR

Modular construction can rise to the challenge of ongoing housing crises or climate change, but more functionally and structurally performant building systems are necessary. Despite facing lower uptakes than what many initial projections anticipated, modular building projects have started to gain traction again as the construction industry is seeking faster, cleaner, cheaper, and most importantly, greener solutions for the built environment. Furthermore, as the modular construction industry is headed towards the adoption of a platform-based approach by harnessing opportunities of Modern Method of Construction (MMC) and Design for Manufacture and Assembly (DfMA), one of the key enablers for a successful implementation is the development of smart and high-performance inter-module connections, which represent the interfaces between structural sub-assemblies and govern construction, deconstruction, and structural behaviour of modular building systems (MBS).

DEMOUNTABILITY AND SCALABILITY

What is easy-to-assemble should also be equally easy-to-disassemble. MBS’ easy deconstruction and potential reuse of their prefabricated prefinished modules are believed to play an essential role in the pursuit of an environmentally friendly building industry, yet the actual disassembly prospects of many existing inter-module connections are debatable. Besides, in high-rise buildings more complex and demanding load transfer paths severely impact the damage levels in the modular framing units, influencing the opportunities for repair, relocation, or reuse. To facilitate the scaling up of modular construction to high-rise projects anywhere in the world, connection systems need to be capable of going the extra mile in the race against natural forces like strong winds and earthquakes.

EARTHQUAKE RESILIENCE AND OPPORTUNITIES FOR REUSE

The practicality of smart and easy-to-demount connections is strengthened by their opportunities for reuse, which in turn, are enabled by efficient damage control. This project aims to address the current challenges of steel MBS related to demountability, seismic performance, and reusability by developing an innovative design of modular building connections with practical construction and deconstruction sequences and improved structural response of high-rise modular buildings to lateral loads. Conceptually, this is done by integrating hyperelastic materials and replaceable structural fuse elements (Video 1) directly into the configuration of inter-module connections. Doing this seeks to alleviate the sway-induced damage on the structural framing of modules and reduce the residual drifts, virtually simplifying the retrofitting and rehabilitation works required post-seismic event, while also enabling promising opportunities for reuse. Several new inter-module connection designs (Fig. 1) have been developed for this purpose and have been tested using nonlinear static and cyclic finite element analyses, while the most promising configurations will be highly optimised through further parametric studies and advanced tools with recently developed algorithms. Mechanical properties like yield load, ultimate load, strength and stiffness degradation or ductility will help characterise the novel joint configuration, while also facilitating the development of design procedures and simplified joint models for structural analysis, which will then be used to assess the global response of the structural system equipped with the proposed connections.

Video 1. Disassembly sequence for an inter-module connection system with steel slit plates as structural fuses and interlocking elastomeric strips

Fig. 1 . Inter-module connection prototypes with structural fuse elements and hyperelastic rubber materials integrated into their configuration

The successful completion of this project will lead to novel connection designs of great practical value, supporting the vision for next-generation, sustainable and performant modular structures.

In collaboration with:

  • SC4