The City of Portland’s Fire Station 21 is located on the east bank of the Willamette River at the foot of the Hawthorne Bridge. The facility’s location on the waterfront allows Portland Fire & Rescue personnel to respond quickly to emergencies on the river and along the Eastbank Esplanade. As part of a seismic upgrade, the City is planning to replace the existing station, which was built in 1961, with a two-story, LEED Gold-certified building. Improvements will also include a new boathouse and dock extension.
GRI evaluated subsurface conditions at the site and provided the design team with geotechnical recommendations for design and construction of the improvements. Soil borings were drilled in the river and on the upland portion of the site and disclosed that the existing station is underlain by soils that are at risk of liquefaction and lateral spreading during a strong earthquake. To stabilize the soil, we recommended ground improvement using compaction grouting, which is performed by advancing a hollow pipe into the soil and pumping concrete under pressure into the soil as the pipe is withdrawn. This technique creates a column of overlapping grout bulbs that densify the surrounding soil and decrease its liquefaction potential.
According to the Daily Journal of Commerce, construction of the project is scheduled to begin this fall.