Situation
The nearby Nike campus and expanding Beaverton economy did not have enough hotels to support the frequent business travelers to the city. This seven-acre site was challenging in every regard. It was surrounded on all sides by major roadways, with starting grades exceeding a 35’ elevation difference on a steep slope, and ongoing water problems that created a marsh-like environment.
Solution
GBI was hired to contain the water, level the site, and prepare it for two separate four-story hotel buildings, a restaurant, and 340 parking stalls. GBI commissioned a subcontractor to install corrosion resistant steel sheets into the ground, going 54 feet deep to retain the soil on the high end of the site.
50,000 cubic yards of soil was removed to leave behind a wall and flatten the grades. To improve the wall appearance, an aesthetic fractured face concrete fascia was applied.
Containing the site water required treating the ground with cement ranging from 5% to 12% by volume to absorb the water. It also structurally stabilized the base for roadways and building. Additionally, two large detention basin systems were installed underground to hold and treat any water entering the site.
To further stabilize the building pads, GBI installed geopiers, using an auger to remove the existing soil piers and replacing it with dynamically compacting crushed rock. We also installed two large CIP concrete retaining walls with decorative fascia, prepped and dug footings for more than 40,000 square feet of building pad, installed 5600 linear feet of wet utilities, 6,700 linear feet of dry utilities, and managed all site landscaping, concrete flatwork, and asphalt paving.
Notable
Sheet pile installation can be very loud, and possibly cause damage to nearby businesses and homes. So GBI opted to use a vibratory hammer, dramatically limiting the impact to the neighboring community.
