Concrete Beam

What it checks

The module designs or checks singly-reinforced rectangular concrete beams, with optional compression rebar for display purposes. It supports T-beam analysis when an effective flange width is provided. The design method follows ACI 318-19, utilizing the Whitney rectangular stress block for flexural strength and the detailed method for shear strength.

Factored loads are applied directly as Mu and Vu, or computed from a uniform load on the span. The sequence of checks includes flexural strength, shear strength, minimum and maximum reinforcement limits, and minimum thickness. If bearing length and grout properties are provided, the module also performs bearing and grout-pad checks.

Inputs

• Geometry - Beam clear span (ft), effective flange width (in), and slab thickness (in) for T-beam analysis.
• Loads - Factored uniform load (kips/ft) or direct factored moments and shears, with span condition specified for moment envelope.
• Material - Concrete strength and rebar yield strength, with bar sizes defined by ASTM A615 nominal areas.
• Support - Bearing length at support (in), non-shrink grout strength (psi), and grout pad thickness (in) for bearing checks.

What it reports

• Flexural Strength - Design moment capacity compared against the factored moment, using the strength reduction factor based on net tensile strain.
• Shear Strength - Concrete shear capacity calculated via the detailed method, compared against the factored shear force.
• Reinforcement Limits - Minimum and maximum steel ratios verified against code requirements for the given section dimensions.
• Minimum Thickness - Required beam depth based on span and support conditions, adjusted for the specified rebar yield strength.
• Bearing Check - Bearing stress and grout pad adequacy evaluated when bearing length and grout properties are provided.

Code references

The engine cites ACI 318-19 §22.2 for flexural strength, §22.5 for shear strength, §21.2.2 for the strength reduction factor, and Table 9.3.1.1 for minimum thickness. It also references §9.6.1 for reinforcement limits and §6.3.2 for T-beam effective width. Grout properties align with ASTM C1107 and ACI 351.1R.

Limits

The module assumes singly-reinforced rectangular sections; compression rebar is optional for display only. It does not handle prestressed members or non-uniform loads directly. Results are engineering aids; the engineer of record is responsible for the design.