Bridges & Highways

The West Mission Bay Drive Bridge, originally constructed in 1949, spans nearly 1,300 feet across the San Diego River Floodway. The existing 11-span structure was built using steel girders with a cast-in-place concrete deck and is supported by reinforced concrete pier walls and abutments founded on groups of 128 to 160 vertical and battered timber piles per support. Over time, the bridge has deteriorated significantly, with many of its steel and concrete elements visibly in disrepair.

The California Department of Transportation (Caltrans) has classified the bridge as both structurally deficient and functionally obsolete, primarily due to the failure of its foundation system under seismic loading. In response, a new seven-span twin bridge is planned to replace the aging structure.

Group Delta, an NV5 Company, played a key role in the replacement project by conducting geotechnical investigations to support the foundation design. To minimize traffic disruptions, much of this work was performed at night. Their contributions included a preliminary investigation for the initial bridge concept, preparation of preliminary reports, participation in foundation type selection alternative analyses, and supplemental site investigations to develop final geotechnical parameters.

Added Value

• Expert Geotechnical Insight: Our team delivered comprehensive geotechnical investigations, including preliminary and supplemental site studies, to inform safe and resilient foundation design for the new twin-span bridge.
• Minimized Public Disruption: Our team conducted much of the fieldwork during nighttime hours to reduce traffic impacts and maintain community accessibility throughout the project.
• Strategic Design Collaboration: Our team played a critical role in foundation type selection and design optimization by contributing to alternative analyses and providing detailed geotechnical parameters.