Performance evaluation of a new anchorage system for unbonded post-tensioned GFRP concrete beams

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Abstract

Conventional steel strand anchorages are unsuitable for fiber-reinforced polymer (FRP) materials. This study evaluates a new bond-type anchorage system for unbonded post-tensioned GFRP bars. Prestressing is applied through a steel strand housed within a component threaded onto an adapter connected to the live-end anchorage. Two concrete beams reinforced with two post-tensioned GFRP bars were tested. The bars in Beam 1 were prestressed to 45.1% of their guaranteed tensile strength, and those in Beam 2 to 27.5%. Concrete strains were monitored during and after prestressing, followed by four-point bending tests. The system effectively transferred the prestressing force with minimal losses and no slippage. Beam 1 exhibited a 13.7% immediate strain loss after the second bar was prestressed. Beam 2 was prestressed two times, with average losses of 6.4% and 15.6% on each side after the first bar was prestressed, and 5.0% and 8.0% after the second. After these immediate losses, the prestressing force remained stable. The anchorages performed effectively under bending, maintaining GFRP bars prestress even after concrete crushing.

Author Biography

Rodrigo de Melo Lameiras, University of Brasília

Bachelor of Civil Engineering at Federal University of Alagoas, Brazil – 2004.
Master of Civil Engineering at Federal University of Rio Grande do Sul, Brazil – 2007.
Doctor of Civil Engineering at University of Minho, Portugal – 2016.
Professor at Federal University of Integração Latino-Americana, Brazil - 2014 to 2017.
Professor at University of Brasília, Brazil - 2017 to present.

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Published

30-03-2026

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Articles in Press

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Original Article

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