Concrete beams reinforced with glass-fiber reinforced polymer (GFRP) bars exhibit large deflections in comparison with steel-reinforced concrete beams because of the low modulus of elasticity of GFRP bars. This paper proposes new equations for estimating the effective moment of inertia of FRP-reinforced concrete beams on the basis of the genetic algorithm and experimental results. Genetic algorithm is used to optimize the error function between experimental and analytical responses. In the experimental part of the study, nine beam specimens were manufactured and tested. In addition, the results of 55 beam specimens tested by other researchers were also used. The effects of elastic modulus of FRP bars, reinforcement ratio, and the level of loading on the effective moment of inertia are taken into account. The proposed equations are compared with different code provisions and previous models for predicting the deflection of FRP-reinforced concrete beams. The values calculated using the proposed equa...

In this paper, the flexural ductility of lap-spliced reinforced concrete (RC) beams is experimentally investigated. Twenty-four specimens were designed and manufactured for laboratory experiments. Concrete compressive strength, amount of transverse reinforcement over the splice length, and the diameter of longitudinal bars were selected as the main variables. The ductility of tested specimens is evaluated based on a previously defined ductility ratio. Results show that concrete strength and amount of transverse reinforcement over the splice have major effects on ductility. With an appropriate amount of transverse reinforcement, a satisfactory ductility response for different concrete strengths can be obtained. The CSA-A23.3-04 Standard provisions on bond strength and ductility of lap-spliced RC beams are evaluated and discussed. This study shows that the provisions in predicting the bond strength of lap-spliced concrete beams are adequate but may not achieve a satisfactory performance for ductility. An equation is proposed to achieve the appropriate ductility.

In this paper, the bond strength of lap-spliced glass fiber–reinforced polymer (GFRP) bars in concrete beams is experimentally investigated. Thirteen beam specimens were manufactured for laboratory experiments. The parameter of transverse reinforcement along the splice length was selected as the main variable for the beam specimens. Other variables were surface properties of GFRP bars, bar diameter, and concrete compressive strength. Test results show that the effect of transverse reinforcement on bond strength between GFRP bars and concrete depends on the surface properties of reinforcing bars. The experimental results obtained in the present study and the results reported in the literature are compared with the current design equation provided by the American Concrete Institute (ACI) Committee 440 guidelines. The equation of ACI Committee 440 for evaluating the bond strength of GFRP bars underestimates the bond strength of spliced GFRP bars confined with large amounts of transverse reinforcement...