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
ϕPn ≥ Pu
ϕMn ≥ Mu
ϕVn ≥ Vu
ϕ Tn ≥ Tu
- Pn,max = 0.80 Po for ties
- Pn,max = 0.85 Po for spirals
- Po = 0.85 f´c (Ag -Ast) + fyAst)
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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 0.01Ag and the maximum as 0.08Ag. In agreement with the commentary a warning is triggered when the reinforcement ratio is over 4 percent due to possible lap splices zones.