Town Hall Station

Innovative Void-Spanning Scaffolding: Melbourne Metro Tunnel Project

SIS delivered an innovative scaffolding solution for Victoria’s Big Build Metro Tunnel Project at Town Hall Station, where a challenging situation required spanning a large escalator void under construction. This complex access need demanded creative engineering and meticulous execution.

The SIS team leveraged their advanced Layher system expertise to design a rolling birdcage scaffold configured as a tension-braced truss. This ingenious approach allowed each bay to be erected from the concrete slab and progressively rolled out as sections were attached. The method enabled the scaffold deck to be fitted from the slab level, dramatically reducing working-at-height risks that would typically be associated with such a void-spanning structure.

Safety was further enhanced by implementing 1500 kg bearing wheels, strategically positioned outside a drilled running plate. This configuration eliminated any possibility of the scaffold accidentally rolling into the void, creating a stable and precisely controlled movement system. Access staircases were installed once the structure was positioned correctly to complete the safe passage solution..

To ensure absolute confidence in the design, SIS first constructed the entire scaffold in their yard as a validation prototype. The team removed intermediate standard supports to accurately replicate the span between the wheels in the field condition, then load-tested the structure to confirm its structural integrity. This pre-build verification process provided complete assurance in the solution before deployment to the active construction site.

The method proved exceptionally cost-effective by eliminating expensive on-site modifications, significantly reduced risk by minimising work-at-height requirements, and delivered superior finish quality since components were assembled in a controlled environment before being maneuvered into the final position.

This successful project execution demonstrates SIS’s advanced engineering capabilities and commitment to innovative solutions for complex access challenges in critical infrastructure development.