Iowa City, Iowa
Design and engineering utilized to minimize the effects of flooding on major vehicle and pedestrian thoroughfares
- Raised the Park Road Bridge and Dubuque Street 1 foot above the 100-year flood level
- Designed to maintain and enhance existing historic sites, parks and vistas
- Reduce closures of primary vehicular and pedestrian thoroughfares to the city, university and healthcare facilities
HNTB created a solution to the problem of more frequent and severe flooding of the Iowa River and increased rainfall, which had closed the Park Road Bridge and Dubuque Street several times since 1993. This prevented passage of the major vehicular and pedestrian thoroughfare to the University of Iowa campus, the city and healthcare facilities for more than 20,000 university employees and more than 30,000 students.
A new bridge was built 10 feet higher than the old one, a three span, reinforced concrete, partial through tied-arch structure with a continuous post-tensioned tie girder supporting the deck and transverse floor beams. The arch ribs rise from footings that appear to float on the surface of the water near each bank. With two piers in the water instead of five, the new bridge no longer impedes the flow of water and blends aesthetically with the views of the new Hancher Auditorium.
Dubuque street is now almost eight feet higher in places through the innovative use of MSE walls supported on brand aggregate pier ground improvements and backfilled with free draining stone. Raised in stages, two lanes remained open to traffic and pedestrians throughout the project.