Hickman Road Bridge Replacement

Transforming a Seismically Vulnerable and Structurally Deficient Structure

An increased height of 75 feet over the Tuolumne River allows for better protection from flooding and erosion.

Pillars ranging in diameter from 100 to 125 inches hold the five piers. Each pillar is 125 feet in depth.

960 feet of additional roadway was added to the current 750-foot-long bridge structure.

Walkways and renovated bicycle lanes were added to the design and construction of the bridge, allowing access to Waterford, California.

Walkways were incorporated underneath the bridge to provide a public park for the community. This also aids with the protection of animal species in the area.

Client: Stanislaus County
Location: Stanislaus County, CA
Services: Engineering, Environmental, Planning, Consulting, and Advisory
Markets: Transportation

Cost: $19 million
Completed: 2021
Region: West

In 1964, the Hickman Road Bridge was constructed to improve the connection between Waterford and Hickman, California, as well as to maintain a major regional north-south roadway in the central part of Stanislaus County. The bridge is located just south of Waterford and crosses the nearly 150-mile-long Tuolumne River that flows between the two communities.

The original structure consisted of a seven-span concrete box girder with concrete abutment and pier walls supported on pile caps founded on driven piles. Starting in 1997, several structural and seismic evaluations were conducted that found the former bridge to be scour critical and seismically deficient.

The old bridge was replaced with a 750-foot-long, 75-foot-tall, five-span, cast-in-place, post-tension concrete box girder structure, supported by seat abutments at each end and intermediate two-column piers. Each pier is supported by two large-diameter, cast-in-drilled-hole piles, ranging in diameter from 100 to 125 inches, and measuring up to 125 feet in depth. The bridge features two 12-foot traffic lanes, two eight-foot shoulders, and one five-foot sidewalk. Additionally, 960 feet of roadway was reconstructed to conform the new bridge to the existing Hickman Road alignment.

The new bridge provides an improved, dependable, and safe connection with multimodal features, while also mitigating a 10-mile detour and bridge unreliability. The structure also aids many industries and services for the greater Stanislaus County, including first responders, students, commuters, and shipping trucks. It also supports a vital water main needed to relieve the overextended Hickman water system.

Additionally, the project improved the natural environment around the bridge by removing 500 tons of existing concrete scour counter measures from the river channel and restoring it to a natural setting. This was accomplished through planting native vegetation along the riverbanks and constructing bat houses on the new bridge.

We provided Stanislaus County with project management, bridge and roadway engineering, environmental, and public outreach services.

750

feet long

feet tall

960

feet of additional roadway