Transport for NSW (TfNSW) have awarded the design and construct contract to Fulton Hogan Construction. Following our work together during the tender design phase, Fulton Hogan engaged Cardno, now Stantec, to undertake the detailed design.
The main purpose of the project is to replace the existing whipple truss bridge with the delivery of a new bridge over the Shoalhaven River. This will provide a new northbound carriageway for the Princes Highway and reuse the existing northbound bridge as a future southbound carriageway.
There are plans to repurpose the existing historic southbound bridge for active transport connectivity once the new bridge and highway upgrade are complete.
Project constraints required the civil design team to look for alternative solutions that satisfied TfNSW design requirements while still providing a constructible solution for Fulton Hogan.
The project includes the upgrade of three major intersections along the Princes Highway and the provision of two new intersections, one on the Princes Highway, and a new roundabout providing access to local communities on Illaroo Road.
Extensive and detailed construction and temporary civil works were designed to allow the construction of the project without impacting traffic in this key section of the highway.
The new bridge has 10 spans and an overall length of 358.7m consisting of 1 x 31.2m, 7 x 38.5m, 1 x 34.0m, and 1 x 21.8m spans. The horizontal alignment is straight except for a minor part of the approach slab at Abutment A. The vertical alignment has an approximate 416m long summit curve with 1.3% and 1.9% grades each way. The superstructure is a continuous, post tensioned, incrementally launched double T girder. The overall depth is 2.7m and the cross section is optimised to simplify casting and launching.
The project also involves the widening of Bomaderry Creek Bridge, which is a 3 span I-girder bridge, widened with TfNSW model planks. Incorporated into that work is the design of 2 retaining walls, a culvert extension and large cantilever sign structures. Our multi-disciplinary team also designed cross drainage for the project, including pipe culverts.
Our team partnered with BCRC who completed a Durability Assessment Report. The aim of the report was to identify the deterioration processes affecting the durability of materials proposed for use in the construction of the bridges and other structures. On identification of the deterioration processes, control strategies were defined and incorporated into the design, so that the materials satisfied the project design life requirements.
Construction is well underway, with completion expected by mid-2024.
When complete, the new four-lane bridge, upgraded intersections and additional lanes on the Princes Highway will improve traffic flow and ease congestion on this major section of the Princes Highway and deliver safer and more reliable journeys within the Nowra-Bomaderry area.