Advanced Concrete Section

Design reinforced, prestressed, and post-tensioned concrete cross-sections with multi-standard compliance, biaxial interaction analysis, fire design, and moment-curvature analysis.

What is the Advanced Concrete Section tool?

The Advanced Concrete Section (ACS) is a cross-section design and analysis tool for reinforced, prestressed, and post-tensioned concrete members. It covers the full design workflow from defining geometry and placing reinforcement through to ultimate and serviceability limit state checks, fire rating verification, and PDF report generation.

ACS performs rigorous nonlinear analysis using fibre-based methods rather than simplified hand-calculation approximations. This means you get accurate results for non-rectangular sections, biaxial bending, complex reinforcement layouts, and elevated-temperature conditions that would be impractical to check by hand.

Capabilities

ACS supports the following analysis and design checks:

Ultimate limit state (ULS)

• Flexural capacity — uniaxial and biaxial bending with axial force, ductility verification
• N-M interaction diagrams — full uniaxial curves and 3D biaxial interaction surfaces
• Shear capacity — concrete and steel contributions per code truss model
• Batch design checks — run multiple load combinations and identify the governing case automatically

Serviceability limit state (SLS)

• Stress checks — verify concrete compressive and steel tensile stresses under service loads
• Crack width control — calculate characteristic crack width per code method
• Deflection parameters — effective moment of inertia, creep multipliers, long-term factors

Prestressing

• Prestress losses — elastic shortening, friction, draw-in, creep, shrinkage, and relaxation
• Transfer and service stresses — verify allowable stresses at jacking and long-term stages
• Ultimate capacity — prestressed section moment capacity with tendon stress increase

Fire design

• Heat transfer analysis — 2D finite element temperature distribution through the section
• Fire capacity — reduced material properties at elevated temperature, fire-rated interaction check
• Fire curves — ISO 834, ASTM E119, and Hydrocarbon fire curves

Advanced analysis

• Moment-curvature (M-$\kappa$) — full nonlinear load-deformation tracing from uncracked through cracking, yielding, and ultimate
• Multiple stress-strain models — rectangular, Hognestad, Mander, parabolic-rectangular, bilinear, and FIB Model Code 2010
• Time-dependent effects — age-adjusted effective modulus method (AEMM) for creep and shrinkage redistribution

Section geometry

• Parametric templates — rectangular, T-beam, L-beam, circular, hollow circular, box girder, I-beam, trapezoidal
• Custom geometry — draw arbitrary polygonal outlines with voids
• Reinforcement placement tools — individual bars, edge patterns, perimeter patterns, linear rows, circular rings, rectangular grids

Design standards

ACS simultaneously supports three major code families:

Select the applicable design code from the materials panel, and all capacity calculations, reduction factors, ductility limits, and serviceability checks adjust automatically.

When to use ACS

Use ACS when you need to:

• Check the capacity of a reinforced or prestressed concrete section under combined actions
• Investigate biaxial bending capacity for columns or edge beams
• Verify fire resistance of a concrete member for a specified fire rating level (FRL)
• Explore the nonlinear response of a section through moment-curvature analysis
• Compare designs across different international standards

Next steps

• Getting started with ACS — create your first concrete section analysis
• Section geometry — define outlines, voids, and templates
• Reinforcement — place and manage reinforcement bars