Version 4.0 (July 2025)

ConcreteSection 4.0 is our biggest update yet—featuring a powerful new analysis engine, expanded interaction diagram views with offset options, additional advanced result data, and Eurocode design support. Watch the Upgrade Guide Video below to see it all in action.

Analysis Engine

• New analysis engine: meshes the entire shape, applies mechanics, and integrates numerically for accurate results
• Fully utilizes the concrete material model for more realistic and detailed behavior under load
• User-controlled mesh refinement balances speed and precision
• Improved triangle integration provides significantly faster calculations

Interaction Surface & Diagrams

• Option to set the failure strain to ε_o or ε_u for interaction surface calculations
• Improved accuracy for diagram generation, especially for asymmetric sections
• Users can now offset the MX, MY, and Flexure diagrams
• Improved calculation of M_o, P_o, and T_o
• Expanded user-defined ranges for interaction points and quadrant slices
• More efficient use of diagram points for faster, cleaner results
• New preferences allow users to set ε_o, ε_u, K, and γ

Stress Results

• New nonlinear solver improves convergence reliability for stress results
• Stress result accuracy has been significantly improved
• Curvature of the section under applied loads is now reported
• Tangent stiffness (the derivative of moment with respect to curvature) is also reported
• Convergence Error—the difference between applied loads and calculated results—is now displayed
• Displays all concrete strains, including tension
• Steel stresses and strains now follow the concrete sign convention (compression is positive)
• Advanced Solver Settings are now exposed:
  • Relative Tolerance
  • Absolute Force Tolerance
  • Absolute Moment Tolerance

Section Properties Results

• New Section Properties tab
  • Available in both Stress Results and Interaction Diagram views
  • Properties are now accessible even when no loads are applied
  • Clearly indicates that properties are constant and load-independent
• Initial Stiffness properties added
  • Reports E_Initial (secant stiffness of concrete at low strains)
  • Displays moments of inertia when the neutral axis is parallel to the global axes
  • Values are calculated at low load levels (i.e., steel is elastic and concrete behaves nearly linearly)
• Uncracked Transformed Properties now use the Initial Stiffness of the concrete constitutive model (E_Initial)

Design

• Added Eurocode 2 specification
• Added European rebar shape database
• Added European rebar material definitions
• Moment unity check is now decoupled from stress results (unity values are still shown even if stress results do not converge)

Reporting

• New interaction surface table: P, MX, MY, εt, ϕ, α, Δ
• New interaction diagram tables: P–MX, P–MY, MX–MY
• New initial stiffness table
• Easily generate moment–curvature and moment–stiffness curves

Upgrade Guide Video

A variety of new features have been added to ConcreteSection 4.0 as discussed in this video.

Additional training videos can be found on the Training Videos page.