REVEALED: How the Grafton bridge will come together
THE first segment may be on top of a pier on the new Grafton bridge, but it may take some time before you see the spans closed.
Fulton Hogan NSW operations manager and project director Richard Petaccia said that there was a lot of work in attaching the segments around each pier and it could take up to a month for each pier to complete the first two segments, well before the remaining segments can be attached to build the partial span from each pier.
"These segments around the piers have a cut-out where we do the diaphragm work. We pour the concrete down through that cut-out opening and it takes about a month to finish the inside and connect it to the pier," he said.
"The focus of work will be to complete the piers and install the first two segments on top of each pier, because there's a lot of work in structurally nailing the segments on top."
Once completed, Mr Petaccia said the process for connecting the piers would be much faster, connecting two to four segments each day when in full production.
"For the cantilever segments, we place temporary stress bars through holes in blisters within each segment that allow us to release the segment from the crane temporarily to allow placement of the alternate segment on the other side of the pier to keep the pier in balance ," he said.
"The segments are permanently fixed using epoxy around the face of each segment and stressed together using high strength steel strands running through tubes at the top of each segment and tie it to its matching pair on the other side."
This process continues each side until the segments reach the midpoint of each span between the piers.
Mr Petaccia said the work had started on the south side of the bridge as that was where the pre-cast units were located.
He said for work on the north side, the pre-cast units would be placed on a barge and taken over.
"The sides won't be connected until we have two spans, and then we do a closure," Mr Petaccia said.