Design development and construction of a new bridge and new culvert, pavement tie ins and roadworks

Cottan Bimbang National Park, NSW

The works included Design and Construct under an MW21 Contract: All design development, documentation, including shop detailing, integration with the Principal’s design and coordination of engineering and survey design disciplines. The works are being performed in an area affected by fire in 2019/2020. Classified as a remote site, rainforest makes up 40% of the Park, with subtropical rainforest in the centre, and warm temperate rainforest and dry rainforest of myrtle further out. Cottan-Bimbang has been nominated for inclusion in the Gondwana Rainforest World Heritage Area.

NSW National Parks owns and maintains the fire access tracks in the Cotton Bimbang National Park. Weather events destroyed a bridge and culvert on a scenic road well inside the Park. Both crossings required demolition and replacement, with a new bridge over the Tobins River and a new concrete culvert crossing to traverse a gully.


Project objectives

The main objectives of the project were to:

• Demolish existing bridge structures

• Design and Construct a new bridge, with a GVM capacity of 15 tonnes

• Design and Construct a new road crossing, with a GVM capacity of at least 15 tonnes

• Repair of existing roads for 20m either side of the new bridge and culvert on the upstream and downstream approaches.

JNC Group’s role

JNCG’ role was to provide Design, Project and Workforce Management, Scheduling, Quality, Safety and final Commissioning. Under the contract we delivered the following documentation:

• Contract Program and monthly updates

• Drawings for Construction and design documents

• Work-as-Executed Drawings

• Quality Management Plan, ITPs and Audit Reports

• WHS Management Plan and Monthly Report

• Contractor’s Monthly Waste Management Report

• Construction Environmental Management Plan

• Demolition Work Plan.


Project constraints + challenges

The impact on the surrounding environment was minimised by ensuring that the footprint of the works was confined to the existing structure’s and fire trail.

• Best practice erosion and sediment controls were implemented, including installation of silt curtains, use of binder on surfaces exposed for greater than 24 hours, staging of works to ensure that exposure of un-stabilised surfaces was minimised.

• A spill kit was maintained at all times near the waterways, storage areas and near waterbodies.

• Care was taken to ensure no animals were disturbed including bat species roosting in the wreckage of the collapsed bridge

• Delivery of materials and concrete pour required careful management due to reduced footprint.


Project snap shot

• Location: Cottan Bimbang National Park, NSW

• Client: NSW National Parks and Wildlife Services (NPWS)

• Award date: April 2021

• Completion date: November 2021

• Key services provided: Project and design Management, Site Management, Management of Subcontractors