Replace Steel in Bridge with GFRP

After extensive laboratory research on glass fiber reinforced polymer (GFRP) as internal reinforcement of concrete, graduate students at the University of Miami are working with Moss Construction Management to substitute steel deck reinforcement with GFRP rebars in the construction of the “Fate Bridge” on campus in an effort to combat future corrosion problems. To date, GFRP has proven to be an effective internal reinforcement for concrete structures as an alternative to steel due to its magnetic transparency, corrosion resistance, durability, high strength-to-weight-ratio, and life expectancy. GFRP is also about four times lighter than steel.

GFRP bars, replacing standard steel rebars for concrete reinforcement, have been laid out on the bridge deck. The next step is casting the concrete. This decreases the amount of labor needed to complete the same tasks in construction sites. This also makes the use of GFRP more advantageous than steel for the bridge project, and it could decrease concrete usage in the future.

Lead by their advisor, the students are installing a state of the art monitoring system with two types of gauges embedded in concrete and directly attached to the reinforcing GFRP and steel rebars in the bridge deck and superstructure. The Vibrating Wire Strain Gauges are designed to measure strains on the steel or GFRP internal reinforcement of certain concrete elements in the bridge. These gauges consist of a steel wire tensioned between two mounting blocks attached to stainless steel pads which are epoxy bonded to the rebars. The Concrete Embedment Strain Gauges are designed to measure strains directly by embedment in concrete using the vibrating principle with a steel wire compressed between two blocks.

 

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