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| Projects - Norman Bridge Emergency Removal |
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Project Name: Norman
Bridge Emergency Removal
Location:
Middle Fork Snoqualmie River, King Country, WA
Client:
King County
Schedule: August
2004 to November 2004
Awards:
The Project:
On July 8th, 2004, Wilder Construction turned in
the winning bid for the emergency removal of the
Norman Bridge on the Middle Fork of the Snoqualmie
River. One week later, Wilder went to work, faced
with the challenge of heavy rains, record setting
water flow and an unsafe structure.
“Old Rickety,” as the bridge was known
by locals, was a timber truss bridge with a 174.5
foot span that was built in 1950. After a new concrete
bridge was built in 1984, the Norman Bridge became
unnecessary and was designated for foot traffic only
in 1997. In 2000, a horse partially fell through
the rotting decking and King County decided to step
in, closing the bridge to all traffic. By 2004,
the bridge had fallen into such a poor state
that King County officials felt its immediate removal
was necessary.
Project Challenges:
The emergency removal of the
Norman Bridge had to be done quickly. Wilder needed
to come up with the method, satisfy a scrupulous
client, do it under a compressed schedule to avoid
the imminent spawning salmon runs; and do it safely.
The day before Wilder went to work, the sky opened
and it rained so hard that the river rose 5 feet
overnight, setting a 62 year record for stream flow.
Wilder installed erosion control measures, a plastic
containment system to catch any pollutants from the deck demolition and a
trolley system to move the deck sections
to the end of the truss for removal. Then Wilder
went to work, removing the failing bridge and any
chance of people getting hurt by walking on it.
As the project marched on, Wilder employed a 90
ton hydraulic crane, then a 180 ton, and finally
at a critical juncture toward the project’s
completion, a 300 ton crane, to remove the final
components of the bridge.
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