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Bega Valley Shire CouncilBega Valley Shire Council

Cobargo, Murrabrine Creek Bridge

Murrabrine bridge concept design, artists impression.
Artists impression of the new Murrabrine bridge.

Project background

The current bridge

The timber bridge on Wandella Road over Murrabrine Creek was constructed as an all timber bridge in 1959 by NSW Department of Main Roads. Since last century a range of structural and heritage assessments, testing, remedial actions and works have been undertaken by Council to  extend the bridge’s life  and maintain functionality.

The bridge is located on a vital service and emergency access route. Wandella Road provides the only practical road link from Cobargo and the Princes Highway to the public school, fire shed, primary producers (timber, dairy and beef) and the Wandella and Yowrie communities. Bega Cheese advises the bridge provides access for the delivery of around seven million litres of milk annually.

The current Murrabrine Bridge, also known as Wandella Bridge is a four span timber and composite bridge with concrete abutments to north and south. Deterioration of the timber support structures necessitated replacement with steel piles, piers, headstocks and bracing in 2012-13 and the northern abutment in concrete in 2017.

The decking has been partially replaced, with the two spans nearest the highway converted to plywood decking, the remainder being transverse decking with timber running boards. Only a small proportion of the original bridge remains. Routine inspection and testing has identified that a number of timber girders and the pedestrian footway require renewal to maintain the existing bridge capacity. Currently, the load limit is 40 tonne with a 10km speed limit, with two 2.7m wide traffic lanes and a 1.2m wide pedestrian path.

The new Murrabrine bridge

The new bridge has been designed by local structural engineer Andrew Marshman of Marshman ONeill Engineers to meet current Transport NSW (SM1600 and GML - General Mass Limit) requirements; that is capacity for heavy vehicles such as fully laden milk tankers, concrete trucks and cattle transports.
 
The design employs standard precast beams spanning from concrete abutments at each end over a single central concrete pier. The new bridge will have two 3.5m wide lanes (one northbound - one southbound) plus 1m shoulders and a 2.5m wide shared pedestrian/cycle path. The existing bridge has 3m lanes and a 1.5m path with restricted load and speed limits.

Together with meeting the functional requirements, the advantages of this simple design include:

  • Reduced footprint in the creek – 3 steel stanchions reduced to one central pier providing a clearer water flow path and minimising the construction impact
  • Raising abutments well above normal flood levels
  • Minimising the extent of earthworks and excavation in the creek channel
  • Retaining the existing northern concrete abutment built in 2017
  • Enabling the retention of traffic access across the bridge for the duration of construction 
  • Relatively simple two stage construction 
  • Longevity and low maintenance – 100 year lifespan
  • Re-configuring the plan geometry of the Princes Highway intersection so centrelines of Wandella Rd and Village St line up making the intersection safer and enabling easier future upgrades
  • Costs are within the funding available 

The detailing of the pedestrian walkway handrails and other street furniture will sympathetically echo historical references incorporating diamond shaped rails, square posts and feature bollards.

The construction and demolition sequence will be undertaken in two stages to ensure that at least one lane of Wandella Rd is always open. 

The staging will enable at least one lane of through traffic over the bridge for the duration of construction

  • Stage 1 involves the construction of the western ‘half’ of the new bridge while maintaining the existing bridge.
     
  • Stage 2 involves using the new western ‘half’ for through traffic, closure and demolition of the existing bridge and then the construction of the eastern ‘half’ of the new bridge which includes the pedestrian path.  

Purpose

The purpose of this project is to replace the existing Murrabrine Creek bridge, which has come to the end of its asset life, with a bridge that fully complies with the Transport for NSW SM1600 traffic loading model to ensure all traffic access, including Gross Mass Limited heavy vehicles, over Murrabrine Creek on Wandella Road at Cobargo.

Funding

Funding for this project has been received from the NSW government’s Fixing Country Bridges grant program ($5.8m) and the Department of Infrastructure, Transport, Regional Development and Communications (DITRLC) $2.3m

Connection to Council's Community Strategic Plan

This project is connect to Council's Community Strategic Plan through Outcome 4, Goal 8 and Outcome 5, Goal 10.

  • Outcome 4: Liveable Places - Goal 8: Our places retain their character and scale, development is well planned, and a range of goods and services are available within our Shire that meet local needs.
  • Outcome 5: Connected Communities - Goal 10: We have a network of good quality roads, foot paths and cycleways connecting communities throughout the Shire and beyond.

Who can I speak to:

Andrew Stewart
Project Manager
Bega Valley Shire Council

Phone: (02) 6499 2222

Email: astewart@begavalley.nsw.gov.au

Timeline of works

 

Frequently Asked Questions

 

News and Updates

 

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