Project Name: Blu Harbor Residential Community Project
Location: Redwood City, CA
Owner: RWC Harbor Communities, LLC
Prime/General Contractor: ECR Construction Corporation
Construction Sector: Residential- Multi Family Housing
Ground Improvement: Deep Soil Mixing (DSM)
- DSM along 3000 feet of the shoreline and under the buildings.
- A total of 121,000 CY of the ground was improved by deep mixing including 57,000 CY for shoreline stabilization and 64,000 CY under buildings and utilities.
- The depth of the DSM elements varied between 28 feet to 37 feet.
- The DSM system along the shoreline consisted of interlocking DSM columns and panels in a longitudinal and transverse direction. This system acted as a below-grade gravity retaining structure resisting both static and seismic loads.
- DSM elements under the building and utilities acted as foundation support.
- The project site was capped with 5 to 7 feet of fill (SC to CH) over 13 to 20 feet of Young Bay Mud (CH).
- Clay with gravel, concrete debris, and brick fragments were encountered within the surficial fill layer.
- Below the Young Bay Mud, potentially liquefiable loose to medium dense sand (SM/SP) deposits approximately 5 to 8 feet thick were encountered.
- below the sand, stiff to very stiff alluvial deposits (CL to MH) was encountered.
Stability Analysis of DMM Buttress
(Source: Rockridge Geotechnical)
A limit equilibrium slope stability analysis was performed by ENGEO and verified by Rockridge Geotechnical using SLIDE to model potential failures under seismic conditions. A peak horizontal ground acceleration of 0.24g was applied to the pseudo-static models. Loading from proposed buildings was applied onto the top of the DSM Buttress.