34
ACT
JUNE 2014
INDUSTRY FOCUS
BRIDGES
SilveradoContractors.
“The lifts are limitedby the capacityof
the cranes,”Riggs said. “Although there
are structuralmembersweighingover
100,000pounds,we are limitedby crane
capacities and radii tovaryingdegrees.An
average rangewouldbe15,000pounds toa
maximumof 40,000pounds.”
While every element of theproject has
beenplanneddown to theNthdegree,
there are still a rangeof challenges to
overcome at every turn.
Environmental protection is ahuge
concern, as is the fact that thebridgehas
layers and layersof coatsof leadpaint.
What is thebiggest challenge for crews
workingat the site?
“Demolishingabridgewhilenot
allowinganything toenter thewaterbelow,
even somuchas a spark froma torch,” said
Riggs. “Containmentmeasures arehung
below thedeck thatwe are removing.We
designed custommanbaskets toget the
torch cutters to theworkand that alsoact
as localized containmentmeasures.”
Demolitionwork is inherently
dangerous, so theprecautionsbeing
takenare ahugepart of everydaywork.
Due to theold leadpaint on thebridge,
crewsmustwearprotective clothingand
respiratoryprotectivedevices. Riggs
saidother safety concerns include fall
protection, firehazards andoverhead
hazards.
There are alsowindowswhereworkhas
tobehalted toallow for environmental
concerns suchas interruptingbirdhabitats
andbirdnesting.Additionally it’s anactive
fisheries area so there are restrictions
related towork that canbedone in the
water.
Riggs said that the joint venturegroup
has coordinatedworkwithavarietyof
entities andgovernment regulations.
“Thesegroups include theU.S. Fishand
WildlifePreserve, TheBayConservation
District, theArmyCorpsof Engineers, the
U.S.CoastGuard,NOAAandothers,”he
said. “There are approximately20agencies
with jurisdictions andpermitswithin the
project limits.”
■
Sheedy Drayage’s cranes sit right on the
edge of the bridge deck in order to get the
man basket to the proper place for burning
the segments loose.
PHOTOS COURTESY OF CALTRANS/SAM BURBANK
About the
Bay Bridge
The Bay Bridge was built in 1936. It
consists of two equal sections: the older
western section connects San Francisco
to Yerba Buena Island and the Eastern
Section connects the island to Oakland.
Before it was closed and the new Bay
Bridge opened in September 2013, the
bridge carried close to 240,000 vehicles
per day on its two decks.
During the 1989 Loma Prieta
earthquake, a piece of the eastern
section’s upper deck collapsed on the
lower deck and the bridge was closed
until it could be fixed.
When the demolition is complete in three
to five years, more than 58,000 tons of
steel and 245,000 tons of concrete will
have been removed.
The Bay Bridgewas split apart inmid-April when the first gap became apparent. Sheedy
Drayage has four cranes on the project, two Link-Belt truck cranes and two Liebherr ATs.
Demolition
facts
■
Length of East Span: 1.97miles
■
Total steel: 48,209 tons
■
Total concrete: 245,470 tons
■
Pier/Foundation steel: 6,522 tons
■
Yerba Buena Island Detour:
1,314 feet
■
Cantilever Truss: 2,420 feet
■
504 foot Truss Spans: 2,569 feet
■
288 foot Truss Spans: 4,104 feet
