Halifax Harbour Bridges has put out a tender for a feasibility study to look at whether to replace or upgrade the MacKay Bridge.

The 1.2-kilometre-long suspension bridge over Halifax harbour opened in 1970.

A tender document posted online Wednesday says the purpose of the study is to determine whether it would be better to upgrade the MacKay and extend its lifespan by 75 years, or remove the existing bridge and replace it.

A new bridge would have a service life of 100 years. There's no indication of the cost of each option.

MacKay is safe, says bridge spokesperson

Halifax Harbour Bridges spokesperson Alison MacDonald said in an email that the MacKay is safe and that testing of the road deck a few years ago found it would remain so until 2040.

She said the study will look at a variety of options for upgrading the existing bridge, such as redecking, strengthening and widening, and replacing the existing bridge.

MacDonald said structural constraints, connections to approach roads, implications for existing infrastructure (roads, buildings and wharves), regulatory issues, environmental considerations, cost, and implications for existing traffic will all be considered for both options.

The tender closes Oct. 5.

Work ongoing at the MacDonald Bridge

Halifax's other harbour span, the Macdonald Bridge, is nearing the end of a major upgrade, which has been underway for more than 2½ years. The Big Lift saw the bridge deck spliced into 20-metre-long sections, weighing up to 150 tonnes, and replaced one by one.

Other work to be done on the Macdonald Bridge this fall includes waterproofing the main cables and finishing installation of roadway lighting. The project will finally be completed next spring when a new platform for performing maintenance underneath the bridge is installed.