Rockridge Geotechnical (RG) performed a geotechnical investigation and provided geotechnical services during the construction of an affordable housing building at 1315 Galindo Street in Concord. The five-story, 62-unit Rick Judd Commons is replacing two commercial buildings previously on-site. The structure consists of five levels of wood-frame construction above a one-story at-grade concrete podium.

The primary geotechnical issues affecting the proposed development included: (1) the presence of undocumented fill at former UST locations that is susceptible to static and seismically-induced settlement, (2) the presence of moderately to very highly expansive near-surface soil, and (3) providing adequate foundation support for the proposed building. The building is also in an Alquist-Priolo Earthquake Fault Zone. RG provided recommendations for the building to be supported on a stiffened shallow foundation system, such as a mat foundation or post-tensioned (P-T) slab-on-grade, bearing on a combination of native alluvium and recompacted UST backfill. RG provided consultation during final design and construction permit application.

RG is also providing geotechnical observation and construction services during construction; these services include observation during the installation of the building’s foundation and during the backfill of excavations after the demolition process.