Scope of Work:
Central was contacted by Home Forward, housing authority of Multnomah County, to perform geotechnical investigation at one of their existing affordable housing developments. Home Forward is planning to proceed with the demolition of 69 existing residential units at their Peaceful Villa community site, just southwest of Mt. Tabor Park. After demolition, the project will include construction of 166 new affordable housing, multi-family residence units in their place.
Our team performed a thorough subsurface investigation of the site, including 10 geotechnical borings up to 51.5 feet below ground surface (BGS) using hollow-stem auger techniques, 6 test pits excavated up to 9.5 feet BGS using a tracked excavator, and groundwater infiltration testing in 4 locations. Laboratory testing of site soil samples included analysis of moisture contents and sieve gradation analysis to determine grain size distribution. It was determined that shallow, spread footings would be geotechnically feasible given existing site conditions.
Central will return to the site during the construction phase to provide construction observation, including in-situ soils assessment, verification of contractor means and methods of installation, and to perform density testing of compacted granular structural fill and Asphaltic Concrete as necessary.
- Due to the age of the site, there was a pre-existing network of buried utilities, including water lines, electrical cables, and even service tunnels. Great care was used while coordinating utility locators and finalizing our exploration program.
- Spacial constraints necessitated using a smaller, limited-access drill rig which could maneuver into the desired areas for sampling.
- Geotechnical Report with recommendations for design and construction, derived from analysis of site data obtained through geotechnical investigation.
- Central Geotech will be on-site during the construction phase to observe in-situ subsurface conditions, in support of adherence to geotechnical conclusions and recommendations.
Despite challenging site conditions, our investigation was sufficient to confirm that shallow, spread footings could be used in design and construction. The due diligence we performed during exploration gave our clients peace of mind during a complex and important project. We have enjoyed working with Home Forward, and have fostered a successful partnership over multiple projects.