Title: Evaluation of Deflection Calculation for Hybrid Reinforced Concrete with FRP and Steel Bars

Author(s): Shui Liu, Xin Wang, Yahia M. S. Ali, Huang Huang, Zhishen Wu

Publication: Structural Journal

Volume:

Issue:

Appears on pages(s):

Keywords: database; deflection; effective moment of inertia; fiber-reinforced polymer (FRP) bar; hybrid reinforcement

DOI: 10.14359/51740717

Date: 3/22/2024

Abstract:
This study presents a critical evaluation of deflection calculation for hybrid reinforced concrete with fiber-reinforced polymer (FRP) and steel bars (hybrid-RC), by employing existing expressions for an effective moment of inertia I_e. A new rational and simple approach is proposed to account for concrete shrinkage restraint caused by both steel and FRP bars and modify the existing reduction factors in the expressions from design codes of ACI 318-19 and ACI 440.11-22. The calculated deflections by the modified expressions, as well as Branson’s equation and the method specified in the design standard of CSA S806-12, are compared with the experimental values from a database including 119 hybrid-RC members. The comparisons indicate that the modified expression from ACI 318-19 provides the most accurate deflection predictions. Whereas the modified expression from ACI 440.11-22, which further includes the consideration of varied stiffness along the member span, proves to be particularly effective for cases with relatively lower reinforcement ratios.