D1.F.5.1 Strength Design
All column designs will be based on a uniform
distribution of reinforcement around the column perimeter. The design options
to control a column design will be based on the
CRDO
parameter setting.
Column resistance is calculated based on strain compatibility and interaction surface calculations.
- φPn ≥Pu
- φMn ≥ Mu
- φVn ≥ Vu
- φTn ≥ Tu
- Pn,max = 0.80 Po for ties
- Pn,max = 0.85 Po for spirals
- Po = 0.85 f´c (Ag -Ast) + fyAst)
The design is performed in two steps considering the longitudinal reinforcement design for axial-bending in an initial step, and the shear and torsion design including the longitudinal reinforcement for torsion tension in a latter pass together with the transverse design.
The minimum area of longitudinal reinforcement is taken as 0.01×Ag and the maximum as 0.08×Ag. In agreement with the commentary a warning is triggered when the reinforcement ratio is over 4% due to possible lap splices zones.