An Introduction to GFRP Rebar and Recent International Field Applications
Presented By: Peter Renshaw
Affiliation: Pultron Composites
Description: An introduction to GFRP reinforcement, it’s advantages over traditional steel reinforcement. The mechanical properties & durability characteristics. A comparison of costs between GFRP rebar and traditional reinforcement. The guides and codes available for design engineers, various brief case studies highlighting a variety of applications where GFRP rebar offers advantages to the engineer and asset owner.
Recent Canadian Developments on Non-Conventional Reinforcing for Concrete Structures, Design Codes, and Applications in Buildings and Bridges
Presented By: Brahim Benmokrane
Affiliation: University of Sherbrooke
Description: In the last decade, there has been a rapid increase in using noncorrosive fibre-reinforced polymers (FRP) reinforcing bars for concrete structures due to enhanced properties and cost-effectiveness. The FRP bars have been used extensively in different applications such as bridges, parking garages, water tanks, tunnels and marine structures in which the corrosion of steel reinforcement has typically led to significant deterioration and rehabilitation needs. Many significant developments from the manufacturer, various researchers and Design Codes along with numerous successful installations have led to a much higher comfort level and exponential use with designers and owners. After years of investigation and implementations, public agencies and regulatory authorities in North America has now included FRP as a premium corrosion resistant reinforcing material in its corrosion protection policy. Currently, AASHTO LRFD Bridge Design Specifications and the Canadian Highway Bridge Design Code contain design provisions for the design of concrete bridge members reinforced with FRP bars. As a result, well over 500 bridges across Canada and USA have been designed and constructed using FRP bars. This presentation presents a summary and overview of different recent field applications of FRP bars in different types of civil engineering concrete infrastructures including bridges.
3-Span GFRP-RC Flat-Slab Bridge and Novel Seawall Over Ibis Waterway
Presented By: Sybille Bayard
Affiliation: CONSOR Engineers
Description: The NE 23rd Avenue Bridge spans over the Ibis Waterway, within a residential neighborhood, in the City of Lighthouse Point, Florida. The existing three-span, low-level bridge, built in 1950, was listed as structurally deficient due to age related deterioration as well as corroded steel in the substructure and foundation piles, likely due to exposure to extremely aggressive marine environments. The replacement bridge utilizes Glass Fiber Reinforced Polymer (GFRP) bars in lieu of Grade 60 carbon-steel and Class IV concrete with added pozzolan material (silica fume, metakaoline or ultrafine flyash) as traditionally used in bridge construction within a corrosive environment. This project presents many unique features for the Florida Department of Transportation. It represents the first GFRP-RC 3-span continuous flat-slab vehicular bridge in Florida and the first soldier pile bulkhead-seawall with GFRP-RC precast panels. The bridge also includes GFRP-RC in the Cast-in-place end bents, intermediate bents and bulkhead caps. All GFRP elements were designed in accordance with the 2018 FDOT Design Manual, the 2009 AASHTO LRFD Bridge Design Guide Specifications for GFRP-Reinforced Concrete Bridge Decks and Traffic Railings, the ACI Guide for the Design and Construction of Structural Concrete Reinforced with Fiber Reinforced Polymer Bars (ACI 440.1R-15) and the Canadian Highway Bridge Design Code (CSA S6-14, Section 16.8.7).
5000ft GFRP-RC Seawall Protects Highway A1A along Flagler Beach
Presented By: Christian Steputat
Affiliation: University of Miami
Description: Severe corrosion damage of existing steel sheet pile bulkhead and extensive erosion damage of adjacent sand dune systems necessitated intervention to avoid future collapse of State Highway SR-A1A along Flagler Beach, Florida. The most recent damage from Hurricane Matthew in 2016, resulted in severe damage and undermining of almost one mile of the coastal highway. Several mitigation solutions had been under investigation since 2005, with the preferred alternative utilizing a secant-pile system that was constructed in early 2019. The secant-pile system minimize impact on the existing sand dunes and adjacent properties during construction. The system can be best described as a series of interconnected auger-cast drilled-shafts that are 36 inches [914 mm] in diameter and 36 feet [11 m] deep. The project required a total of 1,847 secant-piles installed for 4,927 feet [1.502 m] installed along the shoulder of highway in less than five months. The piles were designed with glass fiber-reinforced polymer (GFRP) rebar to eliminate the concern of corrosion and provide extended maintenance-free service life to minimize future construction activities along the coastal dune system. This presentation will describe the challenges and rationale for selection of the preferred alternative, including LCC analysis and potential improvements for similar future applications.
Next Generation GFRP Bar Properties and Bridge Implementation Economics
Presented By: Doug Gremel
Affiliation: Owens Corning Infrastructure Solutions
Description: A consensus is emerging from industry to raise the bar for design material limits of fiberglass rebar. The key parameter driving design implementation being tensile modulus of elasticity. Current ASTM material requirements of 6.5msi (45 GPa) are achieved with 70% plus glass content. Glass fiber contents above 83% are able to achieve 8.75msi (60GPa) and remain within the same measured area tolerances of the existing ASTM D7957. Since glass fibers are less costly than resin, higher glass content has the added benefit of being cost neutral. These higher modulus values have a significant impact on the economics of the implementation of fiberglass rebar making the material much more competitive on a first cost basis. Updates on industry efforts to publish consensus material property limits will be described along with examples of the impact of using a next generation set of material property limits in bridge structures.
6-Span CFRP-PC/GFRP-RC Bridge over Placido Bayou
Presented By: Chris Gamache
Description: The Nathanial J. Upham Bridge carrying 40th Avenue NE over the Placido Bayou in the City of St. Petersburg, Florida. The existing bridge, completed in 1961 and widened in 1990, is a seven-span structure, 336 feet in total length, and constructed of butted prestressed concrete slab units supported by prestressed concrete pile bents. Due to the level of deterioration is the existing beams and piles caused by salt water exposure and the low vertical clearance of 8.5 feet, it was determined that a full replacement was the best option. The new bridge, currently under design, will consist of a six-span structure, 320 feet in total length, with a vertical clearance of 13.2 feet. To extend the life of the structure and reduce future maintenance, all the load carrying bridge components with exposure to the salt water have been designed without carbon-steel. The superstructure will be constructed of prestressed concrete Florida Sab Beams (FSBs) with a cast-in-place concrete topping slab. The FSBs will be prestressed with carbon fiber reinforced polymer (CFRP) tendons. The FSBs, topping slab, and bent caps will be reinforced with glass fiber reinforced polymer (GFRP) reinforcing bars. The prestressed concrete piles will be constructed, as a Contractor’s option, with either CFRP or stainless-steel prestressing tendons and reinforcing bars. Lastly, the sheet pile walls around the end bents and along the approaches will be constructed of GFRP pultruded sheet piles.