Transfer stage parameters for concrete beams prestressed with BFRP bars: Experimental and finite element studies

Abstract

This work is a vital step in enhancing the potential use of a newly developed basalt fibre reinforced polymer (BFRP) bars for prestressing applications. An experimental investigation of four concrete beams has been conducted to determine the transfer length, end-slip, average bond-stress and prestress losses associated with prestressing of concrete beams with BFRP bars. Strain gauges, linear potentiometers, and load cells have been used to measure the strains, slip and loads, respectively, during the pretensioning of the BFRP bars. An initial prestress load of 19 ± 0.5 kN corresponding to an initial prestress of 380 ± 15 MPa has been applied to the BFRP bars, which corresponds to approximately 50% of the ultimate strength of BFRP bars utilized in the present study. The transfer length, end-slip and average bond-stress for 8 mm diameter BFRP bars in concrete with 28-day compressive strength of 40 MPa were 250–500 mm, 1.6–2.7 mm and 1.8–2.6 MPa, respectively. A non-linear FE model has been developed, and the finite element results for the transfer-stage parameters for prestressed concrete beams prestressed using BFRP bars have been estimated and compared with the experimental data.