Parametric Study on Moment Redistribution of Fiber Reinforced Concrete Continuous Beams with Basalt FRP Bars

Abstract

The State of Qatar is continuously suffering from the high temperature and humidity which take place most of the year. This can deteriorate and reduce the lifecycle of the reinforced concrete (RC) structures and may increase the possibilities of the corrosion. Recently, composite materials science was developed and produced new non-corrosive composite material like fiber reinforced polymers (FRP). The natural properties of the FRP bars such as low density with high strength, lightweight material, lower lifecycle cost, and corrosion resistance made it preferable reinforcement material in the construction. Ever since FRP has been used in different concrete elements. However, in continuous beams, the moment redistribution between hogging and sagging sections are still under investigation due to the brittle property of the FRP bars. The aim of this study is to investigate numerically the impact of using basalt macro fibers (BMF) combined with basalt fiber reinforced polymer (BFRP) bars on the moment redistribution of continuous concrete beams. The study is focusing mainly on using the finite element analysis (FEA) to investigate the moment redistribution in continuous beams reinforced with BFRP bars. Different FE models were simulated using ABAQUS 6-14 software. They were successfully calibrated using experimental data for flexural testing of continuous RC beams conducted in the Qatar University structural lab. The FE models were verified through the stress-strain diagrams in which they were matching within the accepted range. The simulated beams were two spans with a size of 200 x 300 x 2000 mm each. An extensive parametric study was conducted using 144 simulated beams to figure out the key parameters that affect the moment redistribution. The parameters taken into consideration were the BMF volume fraction (0%, 0.75% and 1.5%), stirrups spacing (80 mm, 100 mm and 120 mm), and BFRP bars reinforcement ratio (0.6ð€Ÿ©ð€¯•, 1.0ð€Ÿ©ð€¯•, 1.8ð€Ÿ©ð€¯• and 2.8ð€Ÿ©ð€¯•). In addition, statistical regression analysis was performed using Minitab 17 software to generate a formula for calculating the moment redistribution. The FE results showed a significant improvement in the moment redistribution when both top and bottom reinforcement are over-reinforced. Also, the results showed that BMFs have positive effect on the moment redistribution. On the other hand, it revealed that there is no significant effects of stirrups spacing on the moment redistribution.