Mangere Bridge closure again this weekend

Motorists are warned to stay well clear of Auckland's Mangere Bridge and its southern approaches for much of this weekend as engineers have another crack at replacing hefty expansion joints.

Transit NZ and its contractors began a $2 million project last month to replace the six joints, each nine metres long and weighing 10 tonnes, but mammoth traffic jams caused by the closure of the bridge to northbound vehicles prompted a four-week interruption to the job.

After Manukau Mayor Sir Barry Curtis and other community leaders fumed about "mayhem and chaos" in streets throughout their city's southwestern suburbs, Transit went into overdrive this time to to give an early warning of plans to close the bridge's northbound lanes.

It has blitzed the city with 130,000 leaflets and enlisted churches, schools and community groups to help persuade people to avoid driving near the bridge between midnight tomorrow and 11am on Sunday.

Alternatively, they are urged to follow road signs for detours and to allow at least an hour's extra travelling time, especially to and from the airport.

Airlines, travel agents, rental car firms, bus and taxi operators, hospitals, service stations and funeral directors have been notified of the military-like operation - which will be repeated on each of the following two weekends, weather permitting.

Advertisements have run through both mainstream and ethnic media outlets, including a Mandarin-language radio station, and leaflets have been distributed at the recent Pasifika festival.

Manukau City Council is encouraging its staff to minimise trips by car-pooling on Saturday and, although the bridge's southbound lanes will be kept open for traffic to the airport, other motorists are being advised to stay away.

Fans of the Auckland Secondary Schools Maori and Pacific cultural festival, which is expected to attract up to 50,000 people to the Manukau Velodrome on Saturday, should use the Southern Motorway rather than Mangere Bridge to get there.

This is to reduce the overload on eastbound detours, expected to carry heavy traffic flows from the airport, especially from about noon to 2pm.

During the previous closure, traffic was much delayed along just one detour around Manukau Harbour.

The new strategy is to offer two main detours from the airport - Massey Rd and Wiri Station Rd - with provisions to vary these if they become clogged.

Transit will monitor traffic with closed-circuit television cameras and staff on motorcycles and will close the Southwestern Motorway to northbound vehicles at Massey Rd and Kirkbride Rd, rather than allowing them to reach Coronation Rd, as happened last time.

Northern operations manager Joseph Flanagan said Mangere Bridge usually carried up to 3200 northbound vehicles an hour at weekends, and it would be impossible to divert all that to other roads without some delays.

"We are reminding people that there will be delays this weekend and repeating the advice to avoid the area if you possibly can," he said last night.

"We understand this may inconvenience some people and apologise to them in advance for this."

Although one expansion joint was replaced successfully during last month's lane closures, there remained five more to be fitted.

Mr Flanagan said there was a possibility the old joints may fail soon if not replaced, meaning more serious traffic disruption if the bridge had to be closed at short notice.

That would not put the bridge at risk of collapsing, as the joints were simply to accommodate its expansion and contraction as temperatures varied.

Cracks appeared about two years ago in one joint, which was welded together, which suggested the others may also be nearing their end.

Disruption to traffic from a $1.3 million rebuilding project along Hillsborough Rd near the Auckland end of the bridge is likely to ease tomorrow, subject to sealing being completed by tonight along a kilometre section west from Richardson Rd.

Eastbound traffic which has been diverted to other streets for the past three weeks, causing serious initial delays until commuters became used to detours, will be allowed back on Hillsborough Rd after new seal is laid.

Work will start after 9am on Monday on a second section of the key arterial route, between Goodall St and Olsen Ave, but a lane will be available to traffic in each direction, Auckland City Council says.