LAND: LESS THAN $500,000
By Steven Hoefgen, Pacific Pile & Marine
Pacific Pile & Marine (PPM)’s Yakima River Bridges project
included the construction of two temporary bridges
on Interstate 90 in Washington State, one 360-foot-long
bridge in Cle Elum – designated 90/140 – and the other, 580 feet
long, is located in Ellensburg – designated 90/154. Both bridges
cross the Yakima River and are being used to detour I-90 traffic
for two seasons while the existing permanent bridges are
rehabilitated.
The 90/140 temporary bridge is constructed using 30-inch
diameter steel pipe piles, W24 steel wide flange pile caps, W36
steel wide flange girders and precast concrete deck panels. The pile
bents are at a spacing of 45 feet along the length of the bridge. The
steel superstructure for this bridge is primarily salvaged material
and the precast concrete deck panels are salvaged material from
another WSDOT project. The bridge uses Type II barriers and an
asphalt paved roadway surface.
The 90/154 bridge is constructed of 24-inch diameter steel pipe
piles and a double wide flange W24 pile cap for its infrastructure.
The superstructure is an ACROW bridge with asphalt paving. The
pile bents are at 110-foot spacing.
The project also required the of construction of a crane work
access trestle, consisting of 24-inch diameter steel pipe piles, wide
flange pile caps, wide flange girders and timber crane mat decking.
The pile bents were at a 38-foot spacing.
Crews constructed shoring towers to temporarily support the
existing concrete bridge at 90/154. Rehabilitation of the existing
bridges, one for eastbound lanes and the other for westbound
lanes, may temporarily have reduced the EI or stiffness of the
bridge, increasing their dead load deflection. The four shoring towers
were constructed to temporarily resist this additional deflection,
until the full stiffness of the bridge section was restored. The
bents were each constructed of four 24-inch diameter steel pipe
piles, double W24 pile caps, W36x330 40-foot long stringers and a
synchronized hydraulic jacking system.
Use of salvaged material for the structural steel and the precast
deck minimized project costs and re-used material that would
have otherwise been scrapped.
Why were driven piles the best solution?
This site required support of public interstate highway traffic over a
river. The bridge support foundations were required to be installed
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