Gantry ‘Dennis’ nearing the end of the road at Waterview


One of the brightest and most familiar sights on the Auckland construction skyline is coming to the end of its road – Dennis, the yellow lifting gantry working above the Northwestern Motorway, is being sold.

The gantry’s combined mechanical muscle and precision is helping construct the massive interchange ramps as part of the NZ Transport Agency’s Waterview Connection.

The gantry has been lifting 277 precast super T beams into place on the ramps which will connect the Northwestern Motorway and the Waterview tunnels when they open in early 2017.

It will place the last of the beams towards the end of next month, but it’s already joined the list of tools, buildings and vehicles being auctioned off as New Zealand’s largest and most ambitious roading project enters the final stages of construction.

The gantry was designed and built in Italy specifically for the Well-Connected Alliance, which is constructing the interchange and tunnels to connect the Northwestern and Southwestern Motorways. It is 98 metres long and weighs 140 tonnes.

It was named Dennis in memory of a 33-year-old worker on the project who died from cancer and was painted yellow to recognise the partnership between the Well-Connected Alliance and the Cancer Society.

Dennis travels backwards and forwards fetching and lifting the enormous precast concrete beams weighing between 60-69 tonnes and up to 36 metres long and then lowering them into place between the 55 columns supporting the interchange.

The gantry works at night when traffic volumes on the motorway below are light and any necessary safety closures keep disruption to a minimum. It remains perched above the motorway during the day.

'The gantry has eliminated the need for conventional cranes which would have needed to have been moved into place at the start of a work shift at night and then taken away before the morning traffic peaks', says the Transport Agency’s Highway manager, Brett Gliddon.

'It’s saving the project time, reducing disruption for drivers, and avoids the need to use cranes in environmentally sensitive areas.

There is no doubt that Dennis has done its job perfectly.'

Details of the gantry’s auction and other items being sold by the Waterview Connection project are available at: link)

The Well-Connected Alliance says a lot of people have been 'window shopping' on the auction websites for what it calls an “unusual and specialised piece of equipment” and is hopeful Dennis will find a new home at another infrastructure project.

The four ramps the gantry helped construct on the interchange are on three levels and, in total, add up to 1.7 kilometres of viaduct structure.

The interchange and the twin three-lane tunnels connect the Southwestern and Northwestern Motorways to complete Auckland’s Western Ring Route, a 47-kilometre-long motorway between Albany on the North Shore and Manukau in the south.

The completed motorway is one of the government’s Roads of National Significance to support economic growth in both Auckland and its regional neighbours.

It will give drivers a second motorway choice to the Southern and Northern Motorways (SH1) through central Auckland, reduce traffic on local roads, and provide improved links for public transport and for people who walk and cycle.

The Well-Connected Alliance which includes the Transport Agency, Fletcher Construction, McConnell Dowell, Parsons Brinckerhoff, Beca Infrastructure, Tonkin & Taylor and Japanese construction company Obayashi Corporation. Sub-alliance partners are Auckland-based Wilson Tunnelling and Spanish tunnel controls specialists SICE.