Scope of Work:
Central Geotechnical Services conducted a geotechnical investigation at the Fairfield Apartments for Home Forward in downtown Portland. Multiple borings were performed in public right-of-way areas and also inside the footprint of the existing building, which is noted by the City of Portland as a historic site. Our program of subsurface exploration that included two borings drilled to depths of 60 and 80.5 feet and one Cone Penetration Test at a depth of 40 feet below the ground surface. Soil samples were then collected and brought back to our in-house laboratory for analysis. After collecting our investigative data, we prepared a geotechnical report including recommendations for the design and construction of seismic retrofits. The intent of these recommendations was for the building to meet new seismic design standards that reflect an increased understanding of the earthquake hazard in the Pacific Northwest. The existing 4-story building was built in 1911, is currently used as commercial space on the ground floor, and has 82 single-room occupancy units above. Home Forward is in the process to renovate, repair, and update the existing building which will eventually be 75 newly renovated apartments for residents that have experienced chronic homelessness. Central Geotech returned to the project site during the construction phase to observe and document the installation of foundation-underpinning micropiles per our geotechnical recommendation. For these micropiles, a limited-access drill rig was required to operate inside a space the width of a normal residential hallway.
- Drilling in public areas and inside a historic site
- Limited-access equipment and experience was required
- Provision of a technical memorandum evaluating and approving proposed structural fill material
Central Geotech was able to use our experience and network of teammate firms to put together a comprehensive exploration program that was necessary for this delicate project. Working closely with the civil engineer and the general contractor, we were able to assist in the creation of a retrofit design that will provide sufficient seismic support while also fitting into the budgetary and spacial constraints of the project.