SAN JOAQUIN COUNTY – Caltrans will soon begin a bridge maintenance and preservation project that will make necessary upgrades and repairs of the Old River Bridge on State Route 4 (SR-4), located at the San Joaquin/Contra Costa County line, east of Discovery Bay.
This project is required to install a new polyester concrete overlay to the bridge deck (roadway) surface, install new guardrail systems located at the approaches of each end of the bridge, and painting of the bridge steel structure with weather-resistant paint and materials to increase the reliability and serviceability of this 100-year-old swing span bridge.
Additional in-water work will see the existing timber waling and the fenders on the north side of Pier 3 replaced, while the south side of Pier 2 would be supported with new high-density polyethylene walers mounted to the existing timber piles.
This $9.8 million project will be performed by Disney Construction, Inc. (Burlingame, CA) and is scheduled for 220 working days beginning the week of January 25-31, with completion expected on November 10, 2026 (weather permitting).
REQUIRED HIGHWAY AND BRIDGE CLOSURES:
- Full highway closure of SR-4 at Old River Bridge for construction activities on Sunday, February 1, from 7:00 a.m. until 7:00 p.m.
State Route 4 Detour Information:
- Westbound SR-4 travelers: The detour begins at the Tracy Boulevard intersection; south on Tracy Blvd; west on I-205; north on Mountain House Parkway; northwest on Byron Road to SR-4.
- Eastbound SR-4 travelers: The detour begins at the Byron Road intersection; southeast on Byron Road; south on Mountain House Parkway; east on I-205; north on Tracy Blvd to SR-4.
Long-term, 24-hour, one-way traffic control will be implemented on SR-4 at the Old River Bridge beginning at 7:00 a.m. on Monday, February 2, through November 2026.
- Alternating traffic signals (automated flaggers) will be installed at the east and west ends of the Old River Bridge to control traffic and to allow safe passage for motorists.
- This extended one-way traffic control is required due to various factors including limited availability of safe workspace (no median or shoulders to perform work or stage equipment), environmental and in-water work date restrictions.
- Long-term closure of the Old River Bridge swing-span to marine traffic beginning
Caltrans will utilize roadside and portable changeable message signs alerting motorists of the lane closure and potential delays, which are expected to be approximately 15 minutes. For more information on this project, please visit: https://dot.ca.gov/caltrans-near-me/district-10/district-10-current-projects/10-1h360
All work is scheduled to begin as listed, but is subject to change due to traffic incidents, weather, availability of equipment, and/or materials and construction related issues. For the safety of workers and other motorists, please Be Work Zone Alert. For information on Caltrans’ projects statewide, please visit build.ca.gov
