Tilikum Crossing - Northwest Geotech
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Tilikum Crossing
Geotechnical Engineering/Special Inspection/Materials Testing
TriMet, in partnership with several agencies and
municipalities, is currently constructing a 1,720-foot
long four-pier five-span cable-stayed bridge over the
Willamette River. The bridge will be supported by two
main towers (each over 180 feet high), four landside
abutments, and over 3.5 miles of cable. In addition to
the light-rail line and bus route, the bridge will
include two 14-foot wide bicycle and pedestrian paths.
NTI’s parent company, Northwest Geotech, Inc., and
Earth Mechanics, Inc. were selected to perform the
geotechnical investigations and engineering for final
design and construction as part of the winning D/B
team. NGI scoped, estimated, and performed the final
geotechnical explorations and the seismic and static
laboratory testing program, and is the geotechnical
engineer of record for the explorations and subsurface
interpretation, bridge approach embankments, shaft
foundation load testing program, various retaining
walls, and verification of shaft foundation
construction conditions. NGI interpreted all
subsurface conditions and developed the foundation
data sheet along with authoring the Geotechnical Data
Report and the Supplemental Geotechnical Design
Report. Geotechnical engineering responsibility
included surcharging and preloading of the approach
embankments to mitigate settlement, developing the
highly successful O-Cell testing program for the
10-foot diameter shaft foundation elements, and
construction monitoring of all geotechnical related
elements of the project. NTI is currently providing
materials testing and inspection in support of the
contractor’s quality control program, including visual
welding inspection of temporary and permanent bridge
elements, ultrasonic weld evaluation of over one
hundred pile splices, inspection and testing of
thousands of cubic yards of reinforced concrete,
in-place nuclear density testing of structural fills
and asphaltic concrete, ultrasonic inspection of rail
connections, inspection of proprietary anchors, and
inspection and testing of the post-tensioned concrete
bridge spans.