3rd Avenue Firehouse Redevelopment

Prosper Portland

Portland, Oregon

Third Avenue Firehouse

Hart Crowser provided geotechnical consulting to Prosper Portland (formerly Portland Development Commission) under an on-call contract for potential development of the Old Firehouse site downtown. The site is a small parcel bordered by the approach to the Steel Bridge, the Max line, and Naito Parkway. The purpose was to evaluate the feasibility of seismically retrofitting the historical firehouse to preserve the building and generate downtown office space. Geotechnical parameters for broader site development were also evaluated. The two-story brick building had experienced structural damage from previous settlement and is vulnerable to seismic events. We provided geotechnical evaluations of both these elements and worked with the site structural engineer to provide recommendations to address the existing distress to the building and the broader seismic hazards.

The site was geotechnically complex with soft compressible fill at the surface, perched groundwater, loose and settlement-prone soils, and deep sloped liquefiable soils subject to large settlements and severe lateral displacement into the river during the design-level earthquake. To address these problems, Hart Crowser completed:

  • Geotechnical explorations and laboratory testing to determine site subsurface conditions;
  • Preliminary seismic analysis to characterize expected behavior during a design-level earthquake; and
  • Discussion and analysis of the geotechnical elements of the project with the structural engineer to evaluate possible mitigation options and develop cost estimates for the options.

Work products included a geotechnical report that outlined mitigation alternatives and provided preliminary cost estimates for the proposed retrofit of the building.