A First: Precast Network Arch Bridge in Texas
The world’s first precast network arch bridge is changing the landscape of downtown Fort Worth, Texas, as the first two of 12 arches were recently placed. The W. 7th Street bridge is the first-of-its-kind and will serve as a gateway to the city’s cultural district where buildings designed by luminaries such as Louis Khan, Tado Ando and Renzo Piano line the landscape.
“The 7th Street bridge design and construction techniques are further examples of Texas leading the way in innovation,” says Texas Department of Transportation 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 new $26 million W. 7th Street bridge, which replaces its 100-year-old predecessor, is a unique and beautiful design that offers much more pedestrian access. With its series of sculpted network arches and unique, modern architecture, the new bridge serves as the entrance to the city’s vibrant downtown and cultural district.
“This elegant and sophisticated signature bridge will spotlight Fort Worth, the nation’s 16th largest city and growing,” says Fort Worth Mayor Betsy Price. “It’s going to be a beautiful asset for the city.”
TxDOT has a long history of building durable, high-strength, precast concrete bridges quickly and at costs that consistently rank among the least in the nation. The innovative design of the Fort Worth bridge met the challenges of quick construction, aesthetic beauty and improved mobility and safety while also providing a large hydraulic opening to mitigate flood conditions.
“The idea was to turn to our successes in precast technology and mass production – only, we knew we wanted something more attractive for the W. 7th Street bridge,” says 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.”
The contractor, Sundt Construction Inc. of San Antonio, began work more than a year ago with little to no impact on motorists and businesses. The arches were constructed at a nearby casting yard donated by Chesapeake Energy. Each arch is 163.5 feet long and weighs 300 tons. Within the arch, there is a network of stainless steel hangers with clevises and tie-beam connections that protect pedestrians from traffic on the bridge while allowing both motorists and pedestrians to enjoy a nearly unobstructed view of the river. This new construction method is expected to result in seven fewer months of bridge closure compared to a typical 12 months or more using traditional methods.
This spring, all 12 arches will be transported and set on columns located beside the original bridge before it is closed and removed. During the summer, traffic on the bridge will be detoured onto an adjacent city street while the precast beams and deck panels are set, followed by a concrete slab and stainless steel hand rails.
The project is scheduled for completion in Fall 2013.