Washington Boulevard Overhead and Paseo Padre Parkway Underpass Grade Separation, CA

The project consisted of new underpass and overhead structures at the UPRR and the BART tracks, new embankments supported by the MSE walls for the elevated profile grade along Washington Boulevard and the realigned Osgood Road/Driscoll Road. The Hayward Fault passes through a MSE wall at the Washington Boulevard area.  The Paseo Padre Parkway Underpass includes deep soil mixing (DSM) walls for shoring and groundwater cut-off that saved considerable cost.

PARIKH provided geotechnical engineering services that included geotechnical reports combining the foundation recommendations for the bridges, retaining walls, embankments, and trackways.

Challenges

• For the depressed roadway, the Paseo Padre Underpass required to cut and retaining walls below the permanent design groundwater level. The construction adopted Deep Soil Mixing (DSM) wall system for both construction shoring and groundwater cutoff purposes.
• The Hayward Fault crosses the Washington Boulevard area. Our engineer geologist conducted a fault study (the Hayward Fault near Washington Blvd area) to help determinate the bridge abutment location and setback distance. The fault study included a review of geological data and fault trenching,

The project received the 2010 Engineering Excellence Merit Award.