Geoproje

PMM

P-M-M interaction analysis for reinforced-concrete sections

PMM calculates the axial-load and biaxial-bending interaction surface for an RC section and checks load combinations against it.

What it calculates

PMM generates a three-dimensional P-M-M capacity surface for the selected RC section and material model.

  • TS500, TS500-TBDY and ACI 318-19 analysis modes
  • Load-level DCR, capacity point and scale factor
  • Optional moment-curvature curve and shear check

Inputs

Define section geometry, reinforcement, material properties and load combinations.

  • Rectangular or circular section dimensions
  • Longitudinal and transverse reinforcement layout
  • Concrete and steel strength/strain inputs
  • Load combinations with axial force and moments in two directions

Outputs and reports

The results view presents the capacity surface, demand-capacity measures by load and section checks.

  • Nominal/design P-M-M surfaces, DCR and status
  • Section and load inputs with capacity points
  • Compatibility table, preliminary shear check and optional M-φ results
  • Analysis summary, plots and report export

Validation

PMM validation documents browser/server parity and golden regressions; it does not claim independent third-party validation.

  • Old-versus-new golden regressions for four sections and a 20-scenario test report are documented.
  • A TS500 golden case reports DCR 0.760314; a TBDY expected-strength case reports DCR 0.593301.
  • The documentation does not report independent hand-calculation or external-tool validation of the 3D surface.

Who it is for

PMM is intended for structural engineers assessing RC columns and sections under axial force and biaxial bending.

  • Engineers checking section capacity surfaces and load combinations
  • Design teams reviewing DCR, shear and moment-curvature results

Frequently asked questions

How should I interpret DCR?

The guide interprets DCR ≤ 1 as within capacity and DCR > 1 as exceeding capacity.

Do PMM inputs come from a geotechnical site investigation?

No. Section, reinforcement and load-combination data come from structural design or structural analysis.

What does the moment-curvature result include?

For the selected axial load and angle, the documentation lists moment, curvature, neutral axis and concrete/steel strain points.

Does PMM run every building-level seismic check?

No. Its documented scope is section-level P-M-M interaction and the listed section checks.

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