Table 5.

Model equation and values of a and b corresponding to existing model codes.

Model code	Model equation	Values of
		a	b
ACI 31857	$f_{\mathit{sp}}=a\left(f_c^{{}^{\prime }}\right){}^b$	0.56	0.5
ACI 36358		0.59	0.5
CEB-FIP 199059		0.301	0.67
Iravani61		0.57	0.50
Ahmad and Shah62		0.46	0.55
Kim et al.63		0.31	0.71
Tomosawa et al.64		0.291	0.637
JSCE-201265		0.23	0.667
Zain et al.60	$f_{\mathit{sp}}=f_c^{{}^{\prime }}/[a\left(f_c^{{}^{\prime }}\right)+$ b]	0.10	7.11
Larrard and Malier66	$f_{\mathit{sp}}={a+b(f}_c^{{}^{\prime }})$	0.60	0.06