Fairfield Apartments Historical Renovation & Seismic Update

Client: Home Forward

Year: 2021 - 2023

Location: Downtown Portland, Oregon

Features:

  • Geotechnical explorations in public areas and inside a historic building footprint

  • Limited-access equipment and strong experience required

  • Retrofitting of existing shallow foundations

  • Provision of a technical memorandum evaluating and approving proposed structural fill material 

Project Summary

The Fairfield Apartments for Home Forward is located in downtown Portland, and is a 4-story building constructed in 1911. The building was to be renovated, seismically updated, and is now functioning as 75 newly renovated apartments for residents that have experienced chronic homelessness.

This was a challenging historical site for renovations and seismic updating. Central conducted a geotechnical investigation, worked with structural design for seismic retrofitting, and was onsite during the construction phase to observe and document the installation of foundation-underpinning micropiles per our geotechnical recommendations. For these micropiles, a limited-access drill rig was required to operate inside a space the width of a normal residential hallway.

Scope of Work

Central Engineering Services conducted a detailed geotechnical investigation at the Fairfield Apartments, involving multiple borings in both public right-of-way areas and inside the existing building footprint. Given the building's designation as a historic site by the City of Portland, our approach required meticulous planning and execution. The subsurface exploration program included two deep borings reaching depths of 60 and 80.5 feet and a Cone Penetration Test to 40 feet. Soil samples were collected and analyzed in our in-house laboratory to assess their properties. Based on the investigation, we developed a geotechnical report containing seismic retrofit recommendations aimed at bringing the building up to current seismic design standards. As part of the construction phase, we returned to the site to observe and document the installation of foundation-underpinning micropiles, which required specialized limited-access drilling equipment to navigate the confined interior spaces.

Feature

  • Extensive subsurface exploration using borings and Cone Penetration Tests

  • Laboratory analysis of collected soil samples to assess geotechnical properties

  • Development of seismic retrofit recommendations in alignment with updated seismic standards

  • On-site construction observation for the installation of foundation-underpinning micropiles

  • Use of a limited-access drill rig to accommodate tight interior spaces

Results

Through our experience and collaboration with partner firms, Central Engineering Services successfully implemented a comprehensive geotechnical exploration program tailored to the unique challenges of the Fairfield Apartments project. Our thorough analysis and strategic recommendations enabled the design of a seismic retrofit that ensures the structural stability of the historic building while adhering to budgetary and spatial limitations. The project was completed with an emphasis on efficiency, cost-effectiveness, and responsiveness to the needs of Home Forward and the broader community.