Bridge
Demolition, Darling Harbour
Sega Deck - Stage 1
June 2003 - Pedestrian Bridge demolition over Harbour
Street North/South and Bathurst Street.
 Wire
Sawing the Deck
The first part of the job is to seperate a 37 tonne
cantilevered concrete deck joining Sega World to a pedestrian
walkway. The walkway was 8m above the ground approximate
40m long and crossed Harbour St ( north and south )
and Bathurst. St. The deck had to be propped before
the cutting process began. As the deck was cantilevered,
the beams where heavily reinforced with four layers
of y24 bars and eight y16 bars.
The beams on either side were 600mm deep * 900mm wide
with a 1.0m parapet wall. The cross section can be clearly
seen in the "mid - air removal" picture below.
Setting up the Crane 
All the slurry from the cutting process had to be collected
for disposal off site. This was easily achieved using
ECRI's revolutionary slurry pick up system. The slurry
was collected and chemically treated to precipitate
out over 95% of the sediment. The remaining solids were
mechanically filtered from the run-off water. The deck
had a 5 degree fall necessitating cutting at an angle
to allow the entire 35 tonne slab to be removed in one
lift using a 160 tonne crane.
Removing the Deck 
Harbour St (north and south) and Bathurst St were blocked
off for five hours to allow removal of the slab. The
time to set-up and dismantle the crane was approximate
three hours, leaving limited time for the lift. This
made it essential that all steel and concrete had been
cut through. Four 100mm cores were drilled and chains
passed through to ensure the slab was held securely
and there was no chain slippage insuring a clean lift.
The Deck in mid-air
Deck removal was achieved with minimum of disruption
and the road was open in plenty of time for the morning
peak hour traffic flows.
Again the cross section of the deck cut by the wire
saw is clearly visible.
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