What it checks
The module designs a uniformly-loaded one-way slab with a rectangular cross-section, treating the width as a design strip. It applies the approximate method for moment calculation per ACI 318-19 §6.5.2 to determine the dominant positive moment along the span. The engineer applies the factored load externally to the module.
The design method follows ACI 318-19 Chapter 7, utilizing strength-based checks for flexure and shear. The sequence of checks begins with verifying the minimum slab thickness against deflection limits, followed by calculating the required reinforcement ratio for the positive moment. The module also evaluates one-way shear and temperature steel requirements.
Inputs
- Geometry - Span length (inches) and design strip width (inches).
- Material Properties - Concrete compressive strength (psi) and steel yield strength (psi).
- Loading - Factored load applied externally by the engineer.
- Reinforcement - Bar size designation (integer) for area calculation.
- Support Conditions - Boundary condition type for moment coefficient selection.
What it reports
- Minimum Thickness - The required slab depth based on ACI Table 7.3.1.1, adjusted for yield strength if not 60,000 psi.
- Positive Moment - The dominant moment calculated using the approximate method coefficient from ACI 318-19 §6.5.2.
- Reinforcement Ratio - The required steel ratio (ρ) solved from the flexural strength equation.
- Bar Area - The calculated cross-sectional area of the reinforcement based on the nominal diameter.
- Deflection Control - Verification of span-to-depth ratios against minimum thickness limits.
Code references
The engine cites ACI 318-19 Chapter 7, specifically Table 7.3.1.1 for minimum thickness and §6.5.2 for approximate method moment coefficients. The calculations reference the specific clauses for non-prestressed slabs and the adjustment factors for yield strengths other than 60,000 psi as defined in the code tables.
Limits
The module assumes a uniformly-loaded one-way slab and does not account for two-way action or complex load patterns. The bar area calculation uses a nominal diameter formula that matches ASTM A615 areas only up to #8 bars; larger bars may show discrepancies with standard ASTM tables. The module does not calculate negative moment reinforcement or detailed shear reinforcement placement. Results are engineering aids; the engineer of record is responsible for the design.