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©2019 BY QUINCY ENGINEERING, INC.

The historic San Joaquin River Bridge on scenic Italian Bar Road was constructed in 1927 as part of the Big Creek Hydroelectric System. The Bridge spans what historians have dubbed “The Hardest Working Water in the World” due to the intricate multi-dam system used for generating electricity.

February 12, 2020

Quincy Strikes the Right Balance with Italian Bar Road Bridge

The original bridge was raised onto new piers in 1950 to accommodate the rising water levels of Redinger Lake prior to the construction of Big Creek Dam Number 7, and has since served residents, recreationalists, and power plant employees.

Big Creek Dam No. 7 at Redinger Lake (photo courtesy of CA State Water Board)

In 2013, Fresno County determined the historic bridge had reached the end of its service life and could no longer safely support daily traffic. Quincy partnered with the County to replace the bridge, performing an extensive analysis of existing bridge deficiencies and conditions, and working closely with the County to evaluate cost-effective replacement bridge types and span configurations that would accommodate the site’s unique constraints.

Raising the existing Bridge onto new piers in 1950

The original bridge had deteriorated after years of use and was no longer safe.

For the average driver crossing the San Joaquin River on Italian Bar Road, the relatively small bridge might not seem terribly complicated in its design and construction, but as our engineering team can attest, designing a safe, cost-effective, and long-lasting crossing over the steep slopes of this remote section of the river was anything but easy.

Traversing a Tough Site

Constructing Abutment One on Bedrock Exposed by Blasting

Challenge: Crossing Troubled Bridges. One of the biggest hurdles presented by this project was delivering heavy construction equipment and materials to the site because of several smaller bridges along the way that were unable to support heavy loads.

Solution: Bolster the Bridges. The Quincy Team inspected the en route bridges, designing bridge reinforcements as needed, and acquired environmental clearance for one of the approach structures to ensure safe delivery of materials and equipment for the construction of the project.

Temporary Strengthening of a failing bridge on Italian Bar Road leading to the project site

Challenge: Water is King

The hardest working water in the world doesn't stop for anything. Hydroelectric power demands and agricultural water needs in the spring meant that the bridge’s foundation had to be constructed in the winter.

Solution: Designing Work Around the Water

Quincy's project manager coordinated with Southern California Edison (SCE) to develop a construction schedule that would work in conjunction with the low-water season. Quincy's project engineer also planned the foundation locations to maximize structural efficiency while maintaining a constructable design. 

Pier Two, Cast-in-Drilled0Hole Rock Socket Foundation Installation during Low-Water Season in December 2019

Looking at Pier Two from Abutment One in January 2020

Challenge: A Tight Site

Obstacles presented by the small site included limited access for large cranes, and lack of space capable of staging heavy equipment and materials.

Solution: Design to Fit and Maximize Existing Materials

After carefully considering the limitations for delivery and staging of material and construction equipment, the team designed a bridge that could be constructed using smaller pieces, requiring only lightweight equipment loads, and that could successfully be assembled on a constrained site.

In addition, locations were carefully chosen to minimize the bridge footprint and maximize the use of the exposed and shallow depth bedrock. The Quincy team incorporated remnants from the rock blasting and excavations into project improvements, such as structural backfill and rock-slope protection, to reduce the off-haul cost of excavated granite.

This rock slope protection at abutment three is a great

After selection of a two-span structure steel girder bridge, the project team stepped up to the challenge of engineering an affordable yet innovative structure that would integrate seamlessly into the landscape’s rocky outcroppings and oak woodlands while respecting the lake's hydraulic and recreational demands .

Designing a Stand-out Bridge That Still Blends In

Quincy incorporated cutting-edge steel design techniques to increase overall durability and reduce future maintenance costs of the bridge. Over the pier, Quincy developed detailing that eliminates the need for a deck joint by designing the structure as two simple spans for dead load and continuous for live load—a technique with an added bonus of balancing the structure’s weight.  

Finally, the Quincy team selected weathering steel for the plate girders to reduce future painting costs and enhance the aesthetic of the bridge by complementing the rustic landscape.

Throughout the project, the team’s ingenuity and excellence went beyond the bridge itself. Mark Reno, the Quincy project manager, and his team navigated complex co-op agreements between neighboring counties, worked closely with SCE to develop a construction sequence based on the fluctuating water levels in the lake needed for electricity generation, and collaborated with the U.S. Forest Service to identify temporary and permanent impacts and implement agreements.

Designing for the Community

The Italian Bar Road Bridge project also incorporated a raised roadway profile to accommodate safe passage for recreational users on the lake, a priority for project stakeholders due to a tragic boating accident resulting from the past bridge’s limited clearance.

With steel girder erection just around the corner, this structure is well on its way to completion. When finished, the new Italian Bar Road Bridge will strike the perfect balance between public access, environmental sensitivity, maintenance, and cost—serving the San Joaquin River community for years to come.