5.1.6 Confinement Reinforcing
For shear walls with hw/lw greater than 2.0, the boundary elements are confined with spirals or ties with spacing less then 8db.
For buildings designed and constructed in accordance with the 1989 or later editions of Part 2, Title 24, the evaluator may consider this condition as mitigated, and no calculations are necessary. The deficiency is in the ductility of the vertical boundary elements that are required to resist large axial forces. Check the need for boundary elements, per ACI 318. Where boundary elements are required but not provided, amplify the seismic forces for the entire structure by the factor 1.25 (and use 0.8Cd for drift calculation). Conforming buildings which fail this evaluation statement shall be placed in SPC 4, and no calculations are necessary.