GFRP Rebar in the Rehabilitation of Sunshine Skyway Bridge

Historical Background
On May 9, 1980, the cargo ship Summit Venture, blinded by storms, collided with the support columns of the original Sunshine Skyway Bridge, causing a 1,200-foot span to collapse into the bay. At 7:33 a.m., 35 lives were lost—six cars, one truck, and a Greyhound bus plunged 150 feet into the water, with the bus alone claiming 26 victims.

Spanning Tampa Bay and connecting St. Petersburg to Bradenton, the original bridge, built in the 1980s, faced severe degradation from saltwater corrosion and hurricanes, leading to concrete cover spalling and steel rebar corrosion in its piers.

Technical Solution:

GFRP Rebar Replacement——

1. 1. Material Selection: 16mm-diameter GFRP rebar (tensile strength ≥700MPa, elastic modulus 40GPa) replaced corroded steel bar in the bottom one third of pier columns.
   2. Installation: GFRP rebar was inserted into drilled holes in existing piers and secured with epoxy resin mortar for seamless load transfer.

GFRP Composite Strengthening

1. 1. External Wrapping: 3mm-thick unidirectional GFRP sheets were applied circumferentially at 200mm intervals to form a continuous confinement layer.
   2. Dual Reinforcement System: The combination of internal GFRP rebar and external GFRP sheets created an integrated reinforcement system, enhancing shear capacity.

Built for Environments

Corrosion Protection: A polyurethane coating on GFRP rebar virtually eliminated saltwater degradation to 500% Superior Corrosion Resistance.

Fire Resilience: Intumescent coatings provided 2-hour fire resistance, exceeding safety benchmarks for critical infrastructure.

Performance outcome:

• Mechanical Improvements:
  • Shear capacity increased by 35%, flexural rigidity by 28%.
  • Natural vibration period reduced by 12%, damping ratio improved from 1.5% to 3.2%.
• Durability:
  • After 10 years of monitoring, zero corrosion detected on GFRP rebar; concrete carbonation depth reduced by 60%.
• Cost & Schedule:
  • 25% cost savings compared to traditional steel reinforcement; 40% shorter construction time.

Industry Standard
The Federal Highway Administration (FHWA) incorporated the Sunshine Skyway Bridge case into its Guidelines for GFRP Applications in Bridge Rehabilitation (2012), endorsing the technology as a best practice.