Step 5: Design stud shear reinforcement (SSR) if necessary
If any of the calculated column critical sections have a higher demand than capacity (and thus unreinforced stress ratio (USR) > 1.0), the user may choose to have RAM Concept design SSR to strengthen the column, if possible. This is done by selecting the "Design SSR if necessary" option on the punch check properties.
The SSR design is carried out on any sections with an USR > 1.0:
- Check the maximum section stress against the allowable maximum stress - some codes use this provision to prevent highly stressed sections from being reinforced. Please refer to the specific Code section for a detailed description of how each handles this check.
- Install Initial Rails - some initial rails are installed with an arbitrary length. The initial rails are installed to satisfy the maximum transverse spacing requirement of the active Code at the face of the column or support.
- Extend the Rails - the rails are iteratively extended until all cutoff section stresses are within the Code-allowable stresses for unreinforced sections. A cutoff section is one at the Code specified offset distance outside the zone reinforced with SSR.
- Check the calculated/designed stud spacing resulting from the current rail layout. If the spacing doesn't work, rails are added and the design is restarted at step 2.
Note: In punch checks containing slab edges, it is possible for Concept to extend the rails to a distance within the punch check radius, but points projected perpendicular to the slab edge would be outside the punch check radius. In this case Concept may not find the most critical cutoff sections. This can normally be rectified by increasing the punch check radius. The Engineer should inspect cutoff sections for appropriateness and adjust punch check properties as necessary.