The underside of the Colombo Rd bridge, showing the two separate bridge constructions. The bridge carrying southbound traffic, on the left, has “resilience issues”. PHOTO/SAM TATTERSFIELD
PAM GRAHAM
[email protected]
Councillors will today mull over a recommendation to replace the southbound section of the Colombo Rd bridge in Masterton, subject to New Zealand Transport Agency stumping up 75 per cent of the $2.85m cost.
The Colombo Rd crossing of the Waipoua River consists of two bridges.
The east-side bridge, which carries southbound traffic, has “resilience issues”, according to a report to the Masterton District Council’s infrastructural services committee.
It was built in 1900 and extended to six spans from four in 1937. It was repaired when sections collapsed in the 1942 earthquake.
The west-side bridge, which carries northbound traffic, was built in 1973 and has an estimated lifespan of 75 years. It does not have resilience issues.
The bridges were structurally reviewed after new information became available through Waipoua River modelling.
It’s been decided the east-side bridge, already restricted to 44 tonne freight loads, is at risk of cracking or subsiding in a flood or earthquake.
The bridge was not identified as a critical bridge by the Wairarapa Engineering Lifeline project, partially because the west-side northbound bridge would still be a single-lane crossing if the east-side
bridge collapses.
The council has made an application to NZTA for 75 per cent funding and if this is approved, the work has to be done within two years.
The council’s share of a replacement bridge would be $700,000 and it would be consulted on as part of the 2020/21 annual plan.
The report to the committee outlines three options – to repair the bridge at a cost of $1.2m, which would increase the projected life of the bridge by between 25 and 30 years, rebuild it or “wait until structure
failure occurs”.
The do-nothing option set off a storm of protest on social media, but is not recommended in the report. One person pointed out that due to the “unnecessary narrowing” of State Highway 2 at the northern roundabout in Masterton, more people are now using Colombo Rd to avoid traffic issues.
Residents also point out that schoolchildren in the area travel every day over the Colombo Rd bridge.
The report recommends rebuilding the southbound bridge at a cost of $2.85m, subject to NZTA funding approval.
The work will take nine months and during this time the west-side bridge will act as a single lane bridge with traffic lights on it.
