Illinois Installs State’s First Steel Press-Brake Tub Girder Bridge

Photo Credits: Valmont Structures & Champaign County, Illinois

Watch the project video (above)

In September 2021, Champaign County completed the installation of the first prefabricated steel press-brake tub girder (PBTG) bridge in the state of Illinois. The bridge, manufactured by Valmont, provided a $2.00-per-square-foot savings by using steel instead of an alternative precast-prestressed concrete deck beam structure.

Steel Preferred for Durability and Sustainable Benefits

Champaign County is located in the heart of East Central Illinois, approximately two hours south of Chicago, with a population of 208,861 people and a total area of 1,008square miles. Champaign County is home to the University of Illinois and a leader in education, health care, government, high technology, light industry and agriculture.

Champaign County Illinois

Champaign County is located in the heart of East Central Illinois, with a population of 208,861 people and a total area of 1,008 square miles. Champaign County is home to the University of Illinois.

Jeff Blue, P.E., County Engineer for Champaign County, and his crew take care of 30 townships, 200 miles of county roads, and about 1,600 miles of township roads.

“We are in the neighborhood of 600 total bridges that we oversee, maintain and specify within Champaign County – that’s a pretty big bridge system,” says Blue.

Champaign County Steel Bridge

Champaign County almost exclusively installs steel bridges because they offers the longest service life.

Blue prefers to use steel for the bridges located within Champaign County. “On the county system, we are almost exclusively selecting steel because we feel that it gives us our best life, and it is going to give us the best fight against salt that we dump on the bridges,” says Blue.

Sustainability is also a factor which Blue considers when selecting the material for a new structure. “Obviously steel is recyclable, so we like the idea of that [feature]. If we tear down a steel bridge, it may be recycled as steel that somebody else uses for one of their bridges,” says Blue.

Relationship with SSSBA Leads to Interest in Steel Press-Brake Tub Girders

In 2021, short span bridge TR-251 in Champaign County needed to be replaced. The existing 57-foot-long bridge was on a township road over a drainage ditch. The backwall, made from wood, was rotting and the deck needed replacement. Rather than try to repair the structure, Champaign County made the decision to replace the entire bridge.

Champaign County Bridge

Champaign County needed to be replace the TR-251 bridge. The wood backwall was rotting and the deck needed replacement.

Blue, who is also the current Secretary/Treasurer for the National Association of County Engineers (NACE), had heard about the benefits of PBTG from members of the Short Span Steel Bridge Alliance (SSSBA).

“The SSSBA has a really good relationship with NACE,” says Blue. “At one of our NACE meetings, I had a conversation with some of the SSSBA folks about the idea of a steel press-brake tub girder bridge. This idea fit really well for the TR-251 project.”

Steel Press-Brake Tub Girders Provide Savings Over Concrete Alternative

In 2019, Blue had an initial meeting with SSSBA member Valmont Structures to discuss options for the TR-251 bridge replacement using PBTG (download project plans).

“We bid three or four of the precast-prestressed deck beam bridges in Champaign County this year. The cost for the beams in place for those bridges came in at about $84 per square foot. The PBTG price with the precast deck on top, through a proposal from Valmont, was $82 per square foot,” says Blue.

Champaign Illinois Press Brake Tub Girder

The cost of the press-brake tub girder, with the precast deck on top, was $2.00 per square foot less than the concrete alternative.

Based on the overall benefits and cost savings steel provides, Champaign County made the decision to move forward with using PBTG for the replacement bridge project. It would be the first PBTG structure built in the state of Illinois.

Valmont was awarded the project and produced the project-specific superstructure shop drawings and design in accordance with the AASHTO LRFD Bridge Design Specifications and Illinois Department of Transportation (IDOT) “Bridge Manual”.

The shop drawings were stamped by an Illinois structural engineer and reviewed by the engineering firm WHKS. Valmont provided WHKS with a load rating for the bridge superstructure according to the AASHTO “Manual for Bridge Evaluation, Section 6)” and Illinois Department of Transportation Circular Letter 2017-16, “Load Ratings for Local Public Agency Structures” (CL2017-16).

Steel Bridge Produced and Fabricated in the United States

Guy C. Nelson, P.E., Business Development Director of North American Structures for Valmont, provided oversight and management for the sales, design and production of the project.

SSAB Americas

The steel plate for the TR-251 bridge was provided by SSAB Americas located in Montpelier, Iowa.

The bridge was constructed using the Valmont U-Beam, a steel PBTG consisting of AASHTO M270 Grade 50 steel produced and fabricated in the United States. Champaign County acquired the steel plate from steel producer and SSSBA member SSAB Americas located in nearby Montpelier, Iowa.

The Valmont U-BEAM consists of a steel plate formed by cold bending with a press brake. This U-shaped steel plate is then cambered by roll forming to offset any dead load deflections or roadway profile requirements.

Champaign County Press Brake Tub Girders

The Valmont U-BEAM consists of a steel plate formed by cold bending with a press brake. A single row of shear studs is applied to the top flange by an automated stud welder.

Once cambered, bracing angles are welded across the top flanges at specific spacings and steel plate end diagrams are welded at the bearing locations. A single row of shear studs is applied to the top flange by an automated stud welder. These shear studs are spaced for the required fatigue and strength design needs of the project.

“After all of the design and shop drawings were approved, the four steel tub girders were formed with a 60-foot-long press brake from the flat base plate at Valmont’s Valley, Nebraska plate facility,” says Nelson. “Final fabrication—consisting of welded sole plates, angle braced diaphragms, end bearing diaphragms, shear studs and hot-dip galvanizing—were all provided at the Valmont Valley plant.”

Champaign Bridge Deck Press Brake Tub Girder

The fabricated girders were delivered to McCann Concrete Products where a concrete bridge deck was cast.

Once the steel tub girders were completely fabricated, they were delivered to McCann Concrete Products in Dorsey, Illinois to incorporate the final concrete bridge deck. Per the specifications, the concrete used included a waterproofing admixture called Pavix, which  was added as a “salt protection system” to further lengthen the life of the concrete in order to match the long maintenance- free service life of the galvanized steel tub girders.

Download Project Plans

Steel Girders Installed in One Day

After the bridge units were fabricated, galvanized, and the deck was installed, the four bridge sections were individually transported by standard truck and trailer to the jobsite. Each individual 57-foot-long bridge unit weighed approximately 48,000 pounds.

“So, the nice thing about that is they were within weight limit where they could be hauled on a standard-sized truck, with a standard trailer. They were brought in one at a time, and individually set with a 250-ton crane,” says Nelson.

press brake tub girder crane

The four PBTG units were delivered to the jobsite set in one day.

The four PBTG units, measuring 6 feet 4 inches on the outside and 6 feet on the inside, with the precast decks were delivered to the jobsite, and set and placed in one day. The substructure consisted of a 12-inch metal shelf with 35-foot-long piling driven into a silty clay, to provide a good base for the bridge to sit on. A standard concrete abutment was then poured, with riprap out in front.

“The next day, they came back and did the 8-inch closure pours. So, you are looking at two or three days to set the beams and get the closure pours done,” says Blue.

Steel Provides a 100-Year Service Life

According to Nelson, this project includes a 60-year maintenance-free galvanized coating on the steel beams and a water-repellant treatment/additive in the concrete to lengthen the life of the precast concrete deck. This adds up to a 100-year total bridge service life for an upfront cost that is less than the concrete beam option.

Press Brake Tub Girder Champaign Illinois

Champaign County’s press-brake tub girder bridge has a 100-year total bridge service life for an upfront cost that is less than the concrete beam option.

“If I can get 75 to 100 years out of my bridges, I can maybe get a little bit ahead of the curve in the next few years where we will actually have enough money to replace our bridges on a consistent basis in a consistent rotation,” says Blue.

“I am always up for a new challenge and new ideas, and I try to bring those into Champaign County. Hopefully, this will be a kickoff for more PBTG bridges in the state of Illinois,” concludes Blue.

Contact Information

Steel Producer/Mill
David Stoddard
Senior Applications Engineer
SSAB Americas – Montpelier
1770 Bill Sharp Blvd.
Montpelier Steel Operations
Muscatine, Iowa 52761
Tel: 563.381.5759
Email: david.stoddard@ssab.com
Website: https://www.ssab.com/

Steel Fabricator
Guy Nelson, P.E., S.E.
Business Development Director – North American Structures
Valmont Industries, Inc.
28800 Ida Street
Valley, NE 68064
Tel: 616.813.8514
Email: Guy.Nelson@valmont.com
Website: https://www.valmontstructures.com/products-solutions/traffic-mass-transit/bridge-systems

Bridge Owner
Jeff Blue, P.E.
County Engineer
Champaign County Highway Department
1605 E. Main St.
Urbana, IL 61802
Tel: 217.384.3800
Email: jblue@co.champaign.il.us
Website: https://www.co.champaign.il.us/highway/highway.php

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