Fire behavior of concrete T-beams strengthened with near-surface mounted FRP reinforcement

• Behavior of NSM FRP strengthened concrete T-beams exposed to fire is presented.
• Results from fire resistance tests on NSM FRP strengthened T-beams are discussed.
• A model for tracing the fir response of NSM FRP strengthened beams is developed.
• Factors governing fire resistance of NSM FRP strengthened RC beams is discussed.

This paper presents results from experimental and numerical studies on fire behavior of reinforced concrete (RC) T-beams strengthened with near-surface mounted (NSM) fiber-reinforced polymer (FRP) reinforcement. Four RC T-beams, strengthened with NSM FRP reinforcement, were tested by subjecting them to ASTM E119 standard fire exposure and service load conditions. The test variables included load level, restraint conditions, and fire protection applied on the beams. Data from fire resistance experiments is utilized to validate predictions from numerical model to trace the fire response of NSM FRP strengthened concrete T-beams. Results from fire tests and numerical studies indicate that NSM FRP strengthened beams can sustain service loads for three hours under standard fire conditions, even without any external fire protection. In addition, fire induced axial restraint enhances the fire response of NSM FRP strengthened RC beams, while higher load levels lead to much larger deflections and lower fire resistance in these beams.