BG&E played a crucial role as the proof engineer for the cable-stayed bridge over the M80 Freeway in Thomastown, ensuring its extension accommodated additional lanes. By collaborating closely with AECOM throughout the design process, we provided key insights that aligned with the design intent, embodying our philosophy of proactive, stage- by-stage proof engineering.

The M80 Upgrade between Sydney Road and Edgars Road created a system interchange with connections in all directions to the M31 Hume Freeway. This included the expansion of four kilometres of the freeway to three lanes in each direction and improved interchanges at Sydney Road and Edgard Road.

BG&E was engaged by CPB Contractors to undertake structural proof engineering for the project. The detailed design was completed by AECOM.

BG&E undertook the proof engineering of the following structure types

• Major retaining walls.
• Soil-nail walls.
• Prestressed concrete Super-T bridges.
• Carbon fibre bridge strengthening.
• Cable-stayed bridge.
• Major sign gantries.

Notably, the proof engineering for the cable-stayed bridge over the M80 Freeway in Thomastown involved a comprehensive review of the as-built structure to assess locked-in forces and allow for its extension to accommodate new lanes on the freeway.

Subsequently, BG&E worked closely with AECOM at all stages of the design to understand its design intent and design philosophy and, where appropriate, provide proof engineering input to ‘steer’ the design.

This staged proof engineering approach – ‘going on the journey’ with the designer and contractor – is central to BG&E’s proof engineering philosophy. It is not intended to augment the detailed designer’s role (in this case AECOM), but to ensure that proof engineering input and expertise is ‘heard’ at the crucial stages where the cost of change to the design is lowest.