New Gateway Bridge begins journey across the river

The new congestion busting Gateway Bridge has begun its journey across the Brisbane river after the completion of a major milestone.

The completion of the main southern pier (pier no 6) has allowed workers to start construction on the massive 260-metre main span that will link the two sides of the Brisbane River.

The first segment of the 260 metres span was poured last Saturday with the second segment scheduled to be poured on March 6.

Premier Anna Bligh toured the completed southern pier today standing nearly 55 metres above the ground on the top of the massive structure.

Ms Bligh said motorists would now start to see the centre span extend from the southern pier as concrete is pumped into formwork that sits on top of the pier head.

“Over the next few months we will really see this magnificent structure begin to take shape before it eventually joins in the middle this time next year,” she said.

“When finished in mid 2011 this project will cut up to 22 minutes off a journey from Rochedale to the Airport.

“The Gateway Upgrade Project is creating up to 6000 jobs during the four-and-a-half-year construction period and that is incredibly important to Queensland families during these tough economic times.

“At present around 1660 people are working on the project and 120 of those are apprentices.”

The construction of the northern and southern approaches involves pre-cast concrete segments that are lifted into place but the main pier will be cast in mid-air over 50 metres above the Brisbane River.

Structures called form travellers have been installed on top of the two main river pier heads to support the construction of the main river span.

The form travellers, made up of more than 1000 tonnes of steel, are a specifically designed type of formwork used in this method of bridge construction.

The Premier said once each segment was cast, the form travellers would be moved forward on beams using hydraulic jacks in preparation for construction of the next segment.

”In all, the main span consists of 123 concrete segments of varying sizes,” she said.

“At each of the pier heads, the segments are 15 metres deep, while at mid-span, the segments are five metres deep. “

Ms Bligh said the massive gantry structure that had been used to build the northern approach would now be dismantled.

“That means motorists on the existing bridge will now have a clear view of the northern deck of the new Gateway bridge,” she said.

“They will have a clear view of the 700m of the northern approach that is now complete.”

Construction of the main span will require about 3640 tonnes of steel used for reinforcement and tensioning, together with 16,000 cubic metres (or 38,400 tonnes) of concrete.

The main river span substructure, consisting of piles, pile caps, piers and pier heads for the two piers standing in the Brisbane River, has been underway since March 2007, with the new bridge due for completion in mid-2010.

The second Gateway Bridge forms part of the Queensland Government’s $1.88 billion Gateway Upgrade Project. The project also involves upgrading 12 kilometres of motorway from Mt Gravatt-Capalaba Road to the Gateway bridges and seven kilometres of new motorway north to the airport and Nudgee Road.

The project is expected to be completed mid-2011.

Media contact: Premier’s Office 07 32244500

Second Gateway Bridge – key facts and figures

Cross-river spans (superstructure)

• 1 x 260-metre-long cross-river span

• 2 x 130-metre-long side spans

• 123 cast in-situ segments

• Segments – from five to 15 metres deep

• 3640 tonnes steel (reinforcing and tensioning)

• 16,000 cubic metres (38,400 tonnes) of concrete

• 80 workers involved and 12 months to construct

Main piers (substructure):

• Two main piers – 54 metres in height, including pier head

• Main piers support the balanced cantilever cast in-situ main spans

• Each pier has 24 bored foundational piles extending to a depth of up to 50 metres below the river

• Each pile cap is 3.2 metres thick and measures 18 x 20 metres

• Each pile cap contains 1200 cubic metres of concrete

• Each twin-blade pier column contains 1700 cubic metres of concrete and 300 tonnes of steel reinforcing