Symbol	Meaning
${\alpha }_1$	The constant coefficient
$f_c$	The compression strength of concrete
$b$	Width of section
$x$	The height of compression zone
${ f}_y$	The yield strength of reinforcement
$A_s$	The area of reinforcement
M	The flexural capacity of beam
ρs	Reinforcement ratio
Mu,exp	Experimental moment
Mu,pr	Prediction moment
${\sigma }_c$	The concrete stress
${\epsilon }_c$	The concrete strain
${\epsilon }_{c0}$	The compressive strain when the stress just reaches fc
${\epsilon }_{\mathit{cu}}$	The ultimate compressive strain
$A_{si}$	The area of i-th steel reinforcement
${\sigma }_{si}$	The stress of i-th steel reinforcement
$y_{sj}$	The location of i-th reinforcement
ns	The number of steel reinforcement
$\varphi$	The curvature of section
L	The span of beam
$R$	The structural resistance
$S$	The load effect
Z	The limit state function
$\mu$	Model error
$f_{ck}$	The standard value of concrete strength
$f_{yk}$	The standard value of reinforcement strength
${\gamma }_c$	The partial safety factor of concrete
${\gamma }_y$	The partial safety factor of reinforcement
$\psi$	The resistance reduction factor of bearing capacity
$S_{Gk}$	The standard value of dead load
$S_{Qk}$	The standard value of live load
${\gamma }_G$	The partial safety factor of dead load
${\gamma }_Q$	The partial safety factor of live load
$R_d$	The standard value resistance
$P_f$	The failure probability
$N_f$	The number of failure sample
N	The number of MCS sample
β	Reliability index