【正文】 Critical Review of Deflection Formulas for FRPRC MembersCarlos Mota1。 Sandee Alminar2。 and Dagmar Svecova31Research Assistant, Dept. of Civil Engineering, Univ. of Manitoba,Winnipeg MB, Canada R3T 5V6.2Research Assistant, Dept. of Civil Engineering, Univ. of Manitoba,Winnipeg MB, Canada R3T 5V6.3Associate Professor, Dept. of Civil Engineering, Univ. of Manitoba,Winnipeg MB, Canada R3T 5V6
（corresponding author）. Abstract: The design of fiberreinforced polymer reinforced concrete
FRPRC is typically governed by serviceability limit state requirements rather than ultimate limit state requirements as conventional reinforced concrete is. Thus, a method is needed that can predict the expected service load deflections of fiberreinforced polymer
FRP reinforced members with a reasonably high degree of accuracy. Nine methods of deflection calculation, including methods used in ACI , and a proposed new formula in the next issue of this design guide, CSA S80602 and ISIS M0301, are pared to the experimental deflection of 197 beams and slabs tested by otherinvestigators. These members are reinforced with aramid FRP, glass FRP, or carbon FRP bars, have different reinforcement ratios, geometric and material properties. All members were tested under monotonically applied load in four point bending configuration. The objective of the analysis in this paper is to determine a method of deflection calculation for FRP RC members, which is the most suitable for serviceability criteria. The analysis revealed that both the modulus of elasticity of FRP and the relative reinforcement ratio play an important role in the accuracy of the formulas.CE Database subject headings: Concrete, reinforced。 Fiberreinforced polymers。 Deflection。 Curvature。 Codes。 Serviceability。Statistics.Introduction Fiberreinforced polymer
FRP reinforcing bars are currently available as a substitute for steel reinforcement in concrete structures that may be vulnerable to attack by aggressive corrosive agents. In addition to superior durability, FRP reinforcing bars have a much higher strength than conventional mild steel. However, the modulus of elasticity of FRP is typically much lower than that of steel. This leads to a substantial decrease in the stiffness of FRP reinforced beams after cracking. Since deflections are inversely proportional to the flexural stiffness of the beam, even some FRP overreinforced beams are susceptible to unacceptable levels of deflection under service conditions. Hence, the design of FRP reinforced concrete
（FRPRC） is typically governed by serviceability requirements and a method is needed that can calculate the expected service load deflections of FRP reinforced members with a reasonable degree of accuracy. The objective of this paper is to point out the inconsistencies in existing deflection formulas. Only instantaneous deflections will be discussed in this paper.Effective Moment of Inertia Approach ACI 318
（ACI 1999）and CSA
(CSA 1998) remend the use of the effective moment of inertia, Ie, to calculate the deflection of cracked steel reinforced concrete members. The procedure entails the calculation of a un