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Texas precast bridge is a global first

Downtown Fort Worth’s skyline—lined with buildings designed by famed architects such as Louis Kahn, Tadao Ando and Renzo Piano—is transforming once again as the new West 7th Street Bridge nears completion. With its series of sculpted network arches and modern architecture, the new $26 million bridge will serve as the gateway between downtown and the city’s cultural district.

Rendering

“The idea was to turn to our successes in precast technology and mass production—only, we knew we wanted something more attractive for the West 7th Street Bridge,” said Texas Department of Transportation (TxDOT) Structural Engineer Dean Van Landuyt. “Aesthetics were paramount. We tried to do something worthy of the great buildings and great architects who have worked in the city.”

Beams-I

Contractor Sundt Construction Inc., San Antonio, began the project with little to no impact on motorists and businesses. Twelve precast arches (two per span) were carefully designed in a 3D computer model and constructed at a nearby casting yard donated by Chesapeake Energy between July 2012 and February 2013. From early May through the first week of June, lanes on the bridge were reduced while the arches were transported by remote-controlled, self-propelled dollies and placed onto columns beside the bridge’s 100-year-old predecessor.

Beams-II

Heldenfels Enterprises produced 102 floor beams for the project. Each beam is 86-ft. 4-in. long and 5-ft. 8-in. deep at the midpoint or belly, tapering to a thin 16 in. at the ends.

Crews are currently in the intensive phase of construction: demolishing the original bridge; and installing the Heldenfels-produced, TxDOT-designed “floor beams” as well as installing the precast deck panels and concrete deck, barriers and railing. By constructing the bridge this way, it will only be closed for an estimated 150 days—if that, as the target date has been moved up to October—compared to at least a year with traditional bridge construction methods.

“The West 7th Street bridge design and construction techniques are further examples of Texas leading the way in innovation,” said TxDOT Executive Director Phil Wilson. “In addition to being an architectural and engineering landmark for the city of Fort Worth, this precast network arch bridge is a safe, sound and high-quality structure that will benefit both motorists and businesses.”

The bridge will be anchored by six arches on both sides allowing four lanes of traffic, a center lane for a future street car, and wider bike and walking lanes.