Design Characteristics of GFRP Reinforcements at Extreme Temperatures

Abstract:

The article addresses the issue of determining the dependence between the tensile strength of GFRP (Glass Fiber Reinforced Polymer) reinforcement and temperature. Figuring out this dependence is crucial for designing reinforced concrete structures exposed to fire. The newly published generation of standards does not specify any material characteristics of FRP reinforcement at elevated temperatures. The design equations are derived only for steel reinforcement, although this standard allows for the use of FRP reinforcement in the design of concrete structures. For this reason, and based on the available and published experimental data, a robust database of results expressing the decrease in GFRP reinforcement tensile strength as a function of temperature was created and supplemented by the results of our own tests. The characteristic value of the tensile strength was determined as 5% quantile according to the requirements of current a new standard by using two methods: data binning and quantile regression. The resulting (characteristic) dependence of the decreasing tensile strength of GFRP reinforcement on temperature shows zero strength at 550 °C and considers the effect of polymer matrix degradation on the behavior of the reinforcement. The determined curve can be used as a basis for the design of GFRP reinforcement in structures exposed to fire in accordance with EN standards.

• Periodical: Advances in Science and Technology (Volume 176)
• Pages: 167-174
• DOI: https://doi.org/10.4028/p-6JoZ4C
• Online since: May 2026
• Authors: Jakub Ježek*, František Girgle, David Vašátko, Đorđe Čairović, Martin Zlámal, Petr Štěpánek
• Keywords: Elevated Temperature, Glass Fiber Reinforced Polymer (GFRP), Tensile Strength

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