$H$	Specimen heigh	$F$,$G$	Dimensioning factor
$b_{\mathrm{L}}$	Spiral rib width	$E_{\mathrm{c}}$	Modulus of elasticity for concrete
$b_{\mathrm{B}}$	Vertical steel plate width	$E_{\mathrm{s}}$	Steel elastic modulus
$t_{\mathrm{L}}$	Thickness of spiral rib	$f_{\mathrm{y}}$	Steel yield strength
$t_{\mathrm{B}}$	Vertical steel plate thickness	$f_{\mathrm{u}}$	Ultimate strength of steel
$d_{\mathrm{i}}$	Diameter of vertical steel bar	$f_{\mathrm{y}}/f_{\mathrm{u}}$	Steel yield ratio
$B_{\mathrm{s}}$	Spacing of bars	$f_{\mathrm{y}1}$	Steel tube yield strength
$p$	Pitch	$f_{\mathrm{y}2}$	Yield strength of spiral stiffener
$f_{\mathrm{y}3}$	Reinforcement yield strength	${\epsilon }_{\mathrm{c}0}$	Peak strain of unconstrained core concrete under compression
$\delta$	Elongation	${\epsilon }_{\mathrm{cc}}$	Peak strain of confined core concrete under compression
$f_{\mathrm{cu},\mathrm{k}}$	Standard value of compressive strength of concrete cubes	$\xi$	Hoop coefficient of concrete filled steel tube
$f_{\mathrm{c},\mathrm{k}}$	Standard value of axial compressive strength of concrete	$A_{\mathrm{s}1}$	Cross-sectional area of steel tube
		$A_{\mathrm{s}2}$	Cross-section area of spiral rib
		$A_{\mathrm{s}3}$	The cross-section area of vertical steel bar
$f_{\mathrm{c}}$	Design value of compressive strength of outsourced concrete	$A_{\mathrm{c}1}$	Cross-sectional area of core concrete
		$A_{\mathrm{c}2}$	The cross-sectional area of outsourcing concrete
$f_{\mathrm{ck}1}$	Standard value of compressive strength of core concrete	$N_{\mathrm{cr}}$	Cracking load
		$N_{\mathrm{y}}$	Yield load
$f_{\mathrm{ck}2}$	Standard value of compressive strength of outsourced concrete	$N_{\max }$	Peak axial load
$f_{\mathrm{B}}$	Residual stress	$N_{\mathrm{u}}$	Ultimate load
$f_{\mathrm{r}}$	Side limiting stress	$N_1$	Core concrete bearing capacity
		$N_2$	Steel bar bearing capacity
		$N_3$	Bearing capacity of spiral rib steel tube
		$N_4$	Outsourcing concrete bearing capacity
$D/t_{\mathrm{s}}$	Steel pipe diameter to thickness ratio	${\Delta }_{\mathrm{y}}$	Cracking displacement
${\sigma }_{\mathrm{s}}$	Steel stress	${\Delta }_{\max }$	Displacement corresponding to peak load
${\sigma }_{\mathrm{c}}$	Exterior concrete compressive stress	${\Delta }_{\mathrm{u}}$	Displacement corresponding to ultimate load
${\epsilon }_0$	Strain of Encased Concrete When Compressive Stress Reached Design Value	${\Delta }_{\mathrm{u}}/{\Delta }_{\mathrm{y}}$	Deformability
${\epsilon }_{\mathrm{c}}$	Compressive strain of outsourcing concrete	${\Delta }_{\mathrm{u}}/{\Delta }_{\max }$	Emergency capacity
${\epsilon }_{\mathrm{cu}}$	The ultimate compressive strain of normal section concrete	$\gamma$	Constraint factor of spiral rib steel tube
$\phi$	Core concrete enhancement factor under sleeve restraint	$\omega$	Spirally ribbed steel pipe bearing capacity impact coefficient
$\eta$	Comprehensive influence factor of steel tube strength	$\lambda$	External concrete strength reduction factor