Case Study: Design, Construction, and Performance of the La Chancelière Parking Garage’s Concrete Flat Slabs Reinforced with GFRP Bars

Abstract

Parking garages are among the concrete structures that suffer from corrosion and deterioration due to exposure to deicing salts. The 40-year-old La Chancelière parking garage in Québec (Canada) showed severe corrosion-related deterioration and was in need of costly rehabilitation. As its structural system consisted of two-way flat slabs and the steel reinforcement was severely corroded in most of the slabs, the City of Québec (structure’s owner) decided to replace the structure’s flat slabs (a total area of about 3,160 m2) with new ones, while maintaining the main supporting elements (columns and retaining walls). The consulting firm produced two designs with steel reinforcing bars and glass-fiber-reinforced polymer (GFRP) reinforcing bars. Based on the comparative cost analysis of the steel-reinforced and GFRP-reinforced designs, the city opted for GFRP bars. The flat-slab system was designed according to CAN/CSA S806-12 with GFRP bars as main reinforcement, the world’s first application of its type. The slabs were instrumented at critical locations to measure strain with fiber-optic sensors (FOSs) attached to the surface of the GFRP bars or embedded in concrete. This study provides details on the design, construction, and performance of GFRP-reinforced-concrete (GFRP-RC) flat slabs under real service loads and conditions over 3.5 years. In addition, it provides a comparative cost analysis of the steel-RC and GFRP-RC designs. The cost comparison confirms that the initial higher cost of GFRP compared to steel does not necessarily lead to a higher total cost and that a cost-effective design could be achieved.