22.4 Axial Strength or Combined Flexural and Axial Strength
Table 126.96.36.199—Maximum axial strength
|Nonprestressed||Ties conforming to 188.8.131.52||0.80Po||(a)|
|Spirals conforming to 184.108.40.206||0.85Po||(b)|
|Composite steel and concrete columns in accordance with Chapter 10||All||0.85Po||(e)|
|Po = 0.85fc'(Ag— Ast— Apd) + fyAst— (fse— 0.003Ep)Apt||(220.127.116.11)|
where Apt is the total area of prestressing reinforcement, and Apd is the total area occupied by duct, sheathing, and prestressing reinforcement; the value of fse shall be at least 0.003Ep. For grouted, post-tensioned tendons, it shall be permitted to assume Apd equals Apt.
|Pnt,max = fyAst + (fse + Δfp)Apt||(18.104.22.168)|
where (fse + Δfp) shall not exceed fpy, and Apt is zero for nonprestressed members.