Two separate failures of three cantilevered flanges of three precast, prestressed-concrete double-T parking-deck sections—reinforced with a non-code-compliant, high-strength carbon-fiber-reinforced polymer grid—are putting the spotlight on the structural safety of corrosion-resistant FRP grids for transverse reinforcement of double-Ts. The 2015 and 2016 collapses occurred in two garages at Harrah’s Cherokee Casino and Hotel, in Cherokee, N.C. In the second, there was injury to a vehicle and its driver.
The garage owner’s investigating engineer, also the engineer of record, has confirmed there are 100 FRP double-T garages on the East Coast and suspects the number is closer to 200. “This is a public safety issue,” says Jason Reigstad, project manager for Reigstad & Associates Inc., St. Paul, Minn. On the market for about eight years before the collapse, the grid is no longer marketed for this purpose, he adds.