Complete Guide to Shear Wall Design (ACI 318)
The Shear Wall Design Calculator follows ACI 318-19 Chapter 18 for earthquake-resistant structures. It computes minimum thickness, reinforcement ratios, boundary elements, and shear capacity. Essential for high-rise buildings, cores, and dual systems. Pair with Seismic Load and Column Load calculators.
What is a Shear Wall?
Vertical RC element resisting lateral forces (wind, seismic) through in-plane shear and flexure.
- Cantilever: Fixed at base
- Coupled: Linked by beams
- Boundary Elements: Confined edges
Why Design Shear Walls?
- Stiffness: Reduces drift
- Strength: Resists base shear
- Ductility: Energy dissipation
Key ACI 318 Requirements
Minimum Thickness
\( t_w \geq \max(100 \text{ mm}, \frac{L_w}{25}, \frac{h}{20}) \)
Shear Strength
\( V_n = A_{cv} (\alpha_c \sqrt{f'c} + \rho_t f_y) \)
Reinforcement
\( \rho_l, \rho_t \geq 0.0025 \) (ordinary), \( \geq 0.0025 + \frac{P_u}{f'c A_g} \) (special)
Step-by-Step Process
- Input geometry & loads
- Try thickness
- Check shear capacity
- Design rebar
- Check boundary elements
Example: Special Wall
Lw=5m, h=3.5m, Vu=800kN, Pu=1200kN, f'c=30MPa, fy=420MPa:
- t_w = 300 mm
- ρ_v = 0.0038, ρ_h = 0.0030
- Boundary elements required
Typical Values
| Parameter | Ordinary | Special |
|---|---|---|
| Min ρ | 0.0012–0.0020 | 0.0025 |
| Max spacing | 450 mm | 300 mm |
| t_w | ≥ Lw/25 | ≥ Lw/20 |
Applications
- High-Rises: Core walls
- Residential: Elevator shafts
- Industrial: Crane supports
Best Practices
- Use ETABS/SPA for analysis
- Provide confinement
- Detail laps outside plastic hinge
- Check P-delta
Common Mistakes
- Insufficient boundary zones
- Wrong α_c factor
- Ignoring axial-shear interaction
- Poor lap splices
Advanced Topics
- Performance-based design
- Fiber-reinforced walls
- Rocking walls
- Hybrid systems
Conclusion
Proper shear wall design ensures structural integrity during earthquakes. Our Shear Wall Design Calculator delivers ACI-compliant reinforcement and thickness instantly. Integrate with Seismic Load for complete lateral system design. Build safe, resilient structures!