A f	Section area of FRP bars in tensile zone (mm2)
A te	Section area of effective tensile concrete (mm2)
B s	Short-term bending stiffness of bending members (N·mm2)
B s1	GB 50608-2010 calculated value of short-term bending stiffness (N·mm2)
B s2	Modified calculated value of short-term bending stiffness (N·mm2)
B s,exp	Measured value of short-term bending stiffness (N·mm2)
B s,T	Short-term bending stiffness of FRP beam after T °C (N·mm2)
b	Cross-section width of the concrete beam (mm)
c	Distance from the outer edge of tensile FRP longitudinal bars to the bottom edge of tensile zone (mm)
d eq	Equivalent diameter of FRP longitudinal bars in tensile zone (mm)
d i	Nominal diameter of i-th FRP longitudinal bars in tension zone (mm)
E c	Elastic modulus of the concrete (GPa)
E f	Elastic modulus of FRP bars (GPa)
E f,T	Tensile elastic modulus of FRP bars after T °C (GPa)
F u	Ultimate load of FRP-reinforced concrete beams (kN)
f	Mid-span deflection (mm)
f c,T	Axial compressive strength of the concrete after T °C (MPa)
f fu,T	Ultimate tensile strength of FRP bars after T °C (MPa)
f tk	Standard tensile strength of FRP bars (MPa)
h 0f	Distance between joint point of FRP bar and the top surface of the concrete beam (mm)
K b	Reduction coefficient of short-term stiffness
K w	Influence coefficient of high-temperature exposure on the maximum crack width
k f	Bond coefficient
l	Span of the test beam (mm)
M	Bending moment acting on the component section during crack calculation (kN·m)
M c	Calculated ultimate moment (kN·m)
M cr	Cracking moment of the component section (kN·m)
M exp	Measured ultimate moment (kN·m)
M k	Bending moment value by load effect standard combination (kN·m)
M u	Ultimate moment of FRP-reinforced concrete beams (kN·m)
n i	Number of i-th FRP longitudinal bars in tensile zone
P	Load (kN)
P cr	Cracking load of FRP-reinforced concrete beams (kN)
S 1	Coefficient for Equation (11)
T	Temperature of high-temperature exposure (°C)
T g	Glass transition temperature (°C)
v i	Relative bond characteristic coefficient of FRP longitudinal bars in tensile zone
x	Height of the concrete compression zone after high-temperature exposure (mm)
α fE	Ratio of elastic modulus of FRP bars to concrete
β 1	Equivalent rectangular stress diagram coefficient
γ f ′	Ratio of the area of the compression flange to the effective area of the web
ε cu	Ultimate compressive strain of normal cross-section concrete at room temperature
λ f	Influence coefficient of FRP bar type
ε c,mid	Concrete strain in mid-span section of test beams
ξ fb,T	Balanced relative depth of compressive area of FRP beams after T °C
ρ f	Reinforcement ratio of FRP bars
ρ te	Reinforcement ratio of tensile FRP longitudinally bars
σ fk	Stress of FRP bars under load effect standard combination (MPa)
ψ	Uneven tensile coefficient of tensile FRP longitudinal bars between cracks
ω exp	Measured value of maximum crack width (mm)
ω max	Maximum crack width of FRP-reinforced concrete beams (mm)
ω max1	GB 50608-2010 calculated value of maximum crack width (mm)
ω max2	Modified calculated value of maximum crack width (mm)
ω max,T	Maximum crack width of FRP beam after T °C (mm)