Thorndon Overbridge safety improvements


The NZ Transport Agency's (NZTA) $4.5 million safety improvements project on Wellington's SH1 motorway started this month, with work on the replacement of crash barriers along the Thorndon Overbridge above Aotea Quay now underway.

The NZTA state highways manager Rob Whight says that the existing crash barriers were installed when the overbridge was built during the 1970s.

“Being exposed to 40 years of Wellington weather and salt spray has taken its toll and the barrier needs replacing. Technology has also moved on since the ‘70s and we will be replacing the existing barrier with a deeper profile barrier which will provide additional protection to motorists,’ says Mr Whight.

Mr Whight also commented that unfortunately replacing the barrier is not a simple process and it is expected that it will take up to a year to complete the work. The existing steel barrier posts which are cast into the bridge facia panel, and bolted through the bridge structure, also need replacing.

“This means we have to remove the facia panels and existing steel posts before the new posts and barrier can be installed. As sections of barrier are removed and replaced the edge of the bridge will be protected by temporary concrete barriers.”

Mr Wright says that to ensure motorist and workforce safety while working, traffic will be reduced to two lanes and the speed limit reduced to 70km/h through the project.

“However, to minimise delays all lanes will be open during peak hours – that is three lanes Southbound during the morning peak and three lanes Northbound during the afternoon peak and the normal 100km/h speed limit will apply..  We encourage motorists to merge early and safely as directed by the electronic lane control signs and temporary traffic signs,” he says.

To complete the new barriers at the on and off ramps safely, full ramp closures will be required. To minimise disruption this work will be done during a series of night closures and the NZTA will advise the dates for these closer to the time.