The new I-35W Mississippi River, St. Anthony Falls Bridge in Minneapolis, Minn., opened to commuters in September 2008, more than a year after the catastrophic collapse of the old span. The 10-lane bridge with a 100-year lifespan set new records for design-build construction, in part because improved technologies, such as Mirafi® HP570 geotextile, allows multiple activities to take place at the same time.
Mirafi HP570, a woven network of high-tenacity polypropylene yarns, allowed simultaneous construction of a retaining wall and the bridge. The versatile geotextile, manufactured by TenCate™ Geosynthetics North America, Pendergrass, Ga., formed a temporary 10-12 foot fabric-wrapped wall around the bridge abutment, holding banks in place until a retaining wall was completed. Mirafi is inert to biological degradation and resistant to many chemicals, alkalis and acids, allowing it to stand up to the force, flow and water qualities of the muddy Mississippi. For more about Mirafi geotextiles, see the TenCate Web site at www.tencate.com.