Design Parameters

The left column of the optimization screen contains collapsible sections for all design parameters.

Design Settings

• Building Code: ACI 318-19 (default). Eurocode 2 is coming soon — visible in the dropdown but not yet available for optimization.
• Primary Objective: Choose what to minimize — Weight (default), Cost, or Carbon. Multi-objective coming soon.

Material Properties

You can load materials from your Material Library.

Precast Concrete

• Compressive strength f'c (MPa)
• Strength at release f'ci (MPa) — for prestressed designs
• Modulus of elasticity (MPa)
• Density (kg/m³)
• Unit cost ($/kg)
• Embodied carbon coefficient (kgCO₂eq/kg)

CIP Concrete (Composite Designs)

Same properties as precast, for the cast-in-place topping if used.

Rebar Steel

• Yield strength fy (MPa)
• Modulus of elasticity (MPa)
• Density, cost, and ECC

Prestress Steel

• Ultimate strength fpu (MPa)
• 0.1% yield strength fp01 (MPa)
• Modulus of elasticity, density, cost, and ECC

Stirrup Steel

• Diameter (mm) — common sizes: 12.7, 15.24, 17.8
• Number of legs
• Yield strength, modulus, density, cost, and ECC

Fixed Design Inputs

These values are held constant during optimization:

• Clear cover to rebar (mm) — default 25 mm
• Deflection limit — expressed as span/X (e.g., L/360)
• Strand sizes (prestressed only) — multi-select: 12.7, 15.24, or 17.8 mm diameter
• Rebar sizes — multi-select: 9.525, 12.7, or 15.875 mm diameter

Optimization Variables

Some parameters have user-defined ranges that the optimizer searches within:

• Molds: If multiple molds are selected the optimizer will explore feasible variable combinations within each mold.
• Materials: If multiple materials are selected for concrete or steel the optimizer will explore feasible combinations.
• Number of strands
• Stirrup spacing: Min and max (mm) — e.g., 100–600 mm

We add new optimization variables based on user feedback — request them in the community forum.

The optimizer also controls section geometry variables (depth, flange thickness, web width, number of stems) within the constraints of your selected mold geometries.