I-5 Antlers Bridge Replacement

• Replace Aging Infrastructure:
  Construct a new bridge to replace the deteriorating 75-year-old steel truss bridge, enhancing structural integrity and safety.
• Improve Traffic Flow:
  Expand capacity to accommodate current and future traffic volumes, reducing congestion and improving travel times along I-5.
• Enhance Seismic Resilience:
  Design and build a structure capable of withstanding seismic events, ensuring continued functionality during and after earthquakes.
• Minimize Environmental Impact:
  Implement construction practices that protect the surrounding natural environment, particularly the Sacramento River and Shasta Lake ecosystems.
• Incorporate Aesthetic Elements:
  Integrate artistic features into the bridge design to reflect the local culture and natural beauty of the area.

• Bridge Design and Construction:
  • Five-span continuous, post-tensioned, cast-in-place, segmental concrete box-girder bridge.
  • Total length: 1,942 feet; width: 104 feet.
  • Main span: 591 feet.
  • Supported by 12-foot-diameter drilled shafts extending up to 140 feet deep.
• Roadway Realignment:
  • Realignment of a 0.4-mile section of Interstate 5 south of the bridge to improve safety and accommodate the new structure.
• Demolition of Existing Bridge:
  • Controlled demolition of the old steel truss bridge, including underwater debris removal to maintain navigability and environmental standards.
• Environmental Mitigation:
  • Installation of bat habitats beneath the bridge.
  • Use of construction methods that minimized disturbance to aquatic life and water quality.
• Artistic Enhancements:
  • Incorporation of large-scale fish motifs on bridge piers, designed by artist Jerry Stuart, to celebrate the local fishing heritage.

Image: Artistic fish motif painted on the Antlers Bridge piers. Source: A News Cafe.

• Project Initiation:
  • Planning and design phases commenced in 2009.
• Construction Start:
  • Groundbreaking and initial construction activities began in 2010.
• Bridge Completion:
  • The new bridge opened to traffic in September 2016, with all lanes operational by October 2016.
• Demolition of Old Bridge:
  • Demolition and site cleanup concluded in early 2017.

• Materials and Durability:
  • Utilization of high-performance concrete and epoxy-coated reinforcement to extend the bridge’s lifespan beyond 100 years.
• Seismic Design:
  • Compliance with Caltrans Seismic Design Criteria to ensure structural performance during earthquakes.
• Environmental Protection:
  • Implementation of best management practices to prevent pollution and protect water quality during construction.
• Aesthetic Integration:
  • Artistic elements designed to harmonize with the natural surroundings and cultural context of the region.

The Antlers Bridge Replacement project significantly improved transportation efficiency and safety along a critical segment of Interstate 5. By replacing an outdated and structurally deficient bridge, the project enhanced regional connectivity, supported economic growth, and contributed to the resilience of California’s transportation infrastructure. The inclusion of artistic features also fostered a sense of community pride and cultural identity.