Flexural members - Reinforced Concrete with FRP Bars: Mechanics and Design - page 69

ε m = reinforcement tensile strain at midspan

ε u,ave = mean tensile strain at rupture of sample of test specimens

ε v = shear friction strain in reinforcement

ε y = design yield strain

η = ratio of distance from extreme compression fiber to centroid

of tension reinforcement ( d ) to overall height of flexural
member ( h )

λ = multiplier for additional long-term deflection

μ = coefficient of subgrade friction for calculation of shrinkage and

temperature reinforcement

ξ = time-dependent factor for sustained load

ρ′ = ratio of steel compression reinforcement, ρ′ = A s ′/ bd

ρ b = FRP reinforcement ratio producing balanced strain conditions

ρ f = average deterioration factors for modulus of elasticity at a spe-

cific temperature T in o C

ρ f = FRP reinforcement ratio

ρ f ′ = ratio of FRP compression reinforcement

ρ fv = ratio of FRP shear reinforcement

ρ f,ts = reinforcement ratio for temperature and shrinkage FRP

reinforcement

ρ min = minimum reinforcement ratio for steel

σ = standard deviation

σ c = compressive stress, psi (MPa)

χ = curvature

ϕ = strength reduction factor

ω f = tension reinforcement index

ω f b = tension reinforcement index corresponding to balanced failure

4.1 INTRODUCTION

In this chapter, the design of slabs and beams is discussed. Following the
conventional design procedure, this chapter first investigates the structural
analysis of flexural members and elaborates on the parameters that define
the input and determine the output of such analysis methods. Next, flexural
design with fiber-reinforced polymer (FRP) bars is discussed and it is dem-
onstrated how their mechanical behavior can divert the design process
from methods that are well established for steel bars. Flexural design is
completed by detailing and explaining the serviceability provisions of FRP
reinforced concrete (FRP RC) flexural members that, when compared to
steel RC, play a more prominent role in the overall design process. Shear
design of flexural members with or without FRP transverse reinforcement
concludes this chapter. Chapters 6-8 and 10 propose design examples that
clarify the topics covered in this chapter.