Site restoration and clean up is underway at two sites near the I-5 bridge following a pre-construction test project that began in March.
The drilled shaft and driven pile test project occurred near the SR 14 interchange in Washington and at the ODOT permit center in Oregon. The project was conducted to evaluate construction techniques for the replacement bridge foundations and test strength and stability of the soil.
In Oregon, re-paving of the permit center parking lot will occur overnight in the near future. Flaggers will be on-site during the work and permit center operations will not be affected. In Washington, crews are re-seeding the work site and repairing the bicycle and pedestrian pathway. The nearby C-TRAN bus stop, which was closed during the test project, is expected to re-open in mid-August.
During the test project crews installed five driven piles and constructed three drilled shafts. The drilled shafts were 10, 8 and 6 feet in diameter. The piles were driven into the soil using a diesel hammer. The shafts were constructed by oscillating a steel casing into the ground, excavating soil, and filling the void with concrete and a rebar cage. The deepest shaft measured 260 feet in order to reach soils that will not liquefy during a major earthquake.
Test results are currently being analyzed. Results will provide more certainty for the design and construction process, which could lead to cost reductions. Noise and vibration were also monitored and results will be available early next year.
Additional information about the project, including a map and photos of the work, may be found on the CRC website.