The historic Seventh Street Bridge will soon face the eventual fate of all crumbling infrastructure – being demolished and replaced with a new structure that will serve a more populated county than when it was built in 1916.
Last week the Stanislaus County Board of Supervisors approved an $85.2 million contract with MCM Construction, Inc., to replace the 1,170-foot span bridge over the Tuolumne River between Ceres and Modesto. MCM was the lowest responsible bidder with a figure that was nearly eight percent lower than the engineer’s estimate.
With a contingency of $8.5 million and environmental permits, consultant construction support and city of Modesto and county staff costs, the project could top out at $95.7 million. The highest bid received was $120.5 million from Golden State Bridge, Inc.
Work is expected to commence next month with construction taking two years, wrapping up in late 2027 or early 2028.
In July the California Transportation Commission (CTC) approved $15 million toward replacing the Seventh Street Bridge, built in 1916, which is severely deteriorated and is no longer safe for heavy vehicles. The four-ton weight limit means school buses and fire trucks cannot pass over it.
Replacing the bridge has been a priority for the city of Modesto and Stanislaus County officials for years, but until now the project lacked the full funding needed to move forward. With the $15 million state grant, construction is now set to begin next month. The wait for funding has caused considerable cost increases. In 2021 the county estimated that the bridge replacement would cost $50 million. In 2024 that cost was pegged at $75 million.
• The new bridge will be considerably wider than the historic bridge and will include include:
• Two standard travel lanes in each direction with a raised median;
• Five-foot-wide shoulders on each side of the bridge that will serve as Class II bicycle lanes;
• A Class 1 multi-use path on the west side of the bridge;
• Standard sidewalk on the east side of the bridge.
The decorative concrete lions at either end of the bridge will be saved for a new pedestrian plaza that would connect the new bridge with the proposed Tuolumne River Regional Park’s Gateway Parcel and to the Tuolumne River itself.
The historic bridge consists of a series of “canticrete” type trusses supported on reinforced concrete piers and abutments all founded on concrete or timber piling. The Average Daily Traffic (ADT) volume is approximately 15,700 vehicles per day. The Seventh Street Bridge is listed on the Caltrans Local Agency Bridge List with an extremely low sufficiency rating (5.1 on a scale of 0 to 100) because of structural and functional deficiencies. Although the bridge has been considered structurally sound, there is significant spalling, advanced signs of alkali silica reaction, exposed and deteriorating steel reinforcing and considerable deflection at the cantilevered sections. The bridge has been weight restricted to four tons gross load since 1979 and restricted from legal truck load weights since 1937.
The project also will include modifications at the Seventh Street/B Street/Tuolumne Boulevard intersection and at Crows Landing Road at the Seventh Street intersection.
Dry Creek Bridge
In other action, supervisors amended its agreement for professional design services with HDR Engineering, Inc., for the Tim Bell Road over Dry Creek Bridge replacement project, in the amount of $295,757, resulting in a new, not-to-exceed, total contract amount of $3.48 million.
The structurally deficient bridge northeast of Waterford was built in 1915, and the timber deck was replaced with a galvanized corrugated steel deck in 1979. The existing structure consists of a single reinforced concrete arch for a total length of 131 feet and an arch span of 80 feet.
Tim Bell Road has a relatively low average daily traffic but is a key arterial roadway in the eastern part of the county due to fewer roads in that location. The road connects State Route 132 on the south with Warnerville Road on the north, a distance of less than 10 miles.
