Punching Shear Calculator
Calculate punching shear capacity for flat slab-column connections per ACI 318.
Connection Parameters
Typical: ~225 sq ft tributary area x factored load
Punching Shear Check
FAIL
Utilization: 118.3%
Critical Section
Effective Depth (d)
6.75"
Perimeter (bo)
99.0"
Column Ratio (beta)
1.00
Critical Area
613 in²
Applied Stress (vu)
224.5
psi
Capacity (phi*vc)
189.7
psi
ACI 318 Checks
1. Basic: 4*sqrt(f'c)253.0 psi
2. Beta: (2+4/beta)*sqrt(f'c)379.5 psi
3. Perimeter: (2+alpha*d/bo)*sqrt(f'c)299.0 psi
Governing vc253.0 psi
Design Capacity
126.8 kips
Max with shear reinf: 190.2 kips
Options to increase capacity:
- Increase slab thickness
- Increase column size
- Use higher strength concrete
- Add drop panel or column capital
- Use shear studs or stirrups
Punching Shear Design Notes
Critical Section
Located at d/2 from column face. For circular columns, use equivalent square with same area.
Alpha Values
- Interior columns: alpha = 40
- Edge columns: alpha = 30
- Corner columns: alpha = 20