Shear Strength and Behavior of Haunched Concrete Beams Reinforced with Basalt Fiber Reinforced Polymer BFRP Bars

Haunched or tapered beams represents elements with varying effective depth along their span length. Several researchers have focused on such elements reinforced with conventional steel bars. However, in the last four decades, there has been a shift towards utilizing fiber-reinforced polymer FRP bars as an alternative to steel bars. Consequently, this study aims to show the performance of basalt fiber-reinforced polymer BFRP bars in the shear behavior of these specific members. The experimental part which included of Eight simply supported BFRP reinforced concrete beams were subjected to testing under constant shear span, to examine two significant parametric studies, namely the tapered angles α and the BFRP reinforcement ratio ρf. They were separated into two equal groups. Each group had been reinforced with a different longitudinal BFRP ratio, which varied from around 1–2.1%. Among the group, one beam had a prismatic shape, while the other three beams had inclination angles of 4°, 7.96°, and 11.76°, respectively. The test findings revealed that beams with the lowest tapered angle had an average drop in shear strength of around 4%. In contrast, a rise in tapered angles led to a corresponding rise in shear strength, with an average range of around 8.23% and 14.08% for beams with a reinforcement ratio of about 1% and 2.1%. Furthermore, the second part is analytical part by using three different modified equations in code provisions based on a critical effective depth proposed in the available literature for beams reinforced with conventional bars since 1982. According to the results, all modified code guidelines exercised safe in predicting the shear strength of BFRP tapered beams. © The Author(s), under exclusive licence to Shiraz University 2024.