Independent PT analysis and design comparisons

PTKalc verification against established post-tensioned concrete software.

Review direct benchmark studies between PTKalc and RAPT covering reinforced-concrete and post-tensioned continuous beams. The published records compare equivalent geometry, material properties, support conditions, tendon geometry, prestress force, loading and design combinations across structural analysis, ultimate design and serviceability behaviour.

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Like-for-like benchmark models

Geometry, sections, materials, supports, applied loading and design combinations are aligned wherever applicable between PTKalc and RAPT.

Prestress checked independently

Post-tensioned studies compare tendon geometry, effective prestress, equivalent tendon loading and the resulting prestress-only structural response.

Serviceability methods explained

Deflection comparisons are supported by a detailed explanation of cracking, effective stiffness, tension stiffening, creep, shrinkage and long-term analysis.

Published verification records

Continuous beam benchmark studies

The current verification set covers reinforced-concrete, rectangular post-tensioned and flanged post-tensioned sections using a common multi-span benchmark arrangement.

24 pagesReinforced concreteRAPT comparison

Rectangular reinforced-concrete beam

A five-span continuous reinforced-concrete beam benchmark comparing PTKalc with RAPT from elastic analysis through ultimate design and long-term deformation.

Self-weight, superimposed dead and live-load response
Ultimate and permanent load combinations
Flexural and shear reinforcement requirements
Cracked-section and long-term deflection sensitivity

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26 pagesPost-tensioned concreteRAPT comparison

Rectangular post-tensioned beam

A continuous rectangular PT beam benchmark extending the comparison to tendon geometry, prestress losses, equivalent tendon loading and prestress-dependent design behaviour.

Tendon profile and effective prestress comparison
Prestress-only moment and shear response
Ultimate flexural and shear design behaviour
Long-term deformation and cracking sensitivity

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26 pagesFlanged PT sectionRAPT comparison

Flanged post-tensioned beam

A flanged-section PT benchmark testing the same analysis and design framework at substantially higher member actions and with non-rectangular section behaviour.

Flanged-section geometry and tendon profile
Prestress, gravity and factored structural actions
Flexural and shear reinforcement envelopes
Serviceability response with local cracked stiffness

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76 pagesTechnical manualMethodology

PTKalc analysis & design manual

The supporting technical manual documents the engineering implementation behind the verification studies, from tendon profile generation to finite-element analysis and concrete design.

Equivalent load method and tendon profile equations
Friction losses, anchorage draw-in and prestress force
Finite-element representation and load combinations
AS 3600 flexure, shear and long-term serviceability methodology

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How to read these comparisons. Agreement of the elastic moment and shear diagrams verifies the common structural basis of the benchmark models. The deformation results are then interpreted in the context of the different methods used by PTKalc and RAPT for cracking, tension stiffening, creep, shrinkage and load history. The published records are therefore engineering verification studies rather than claims of numerical identity between independently implemented programs.

What is being verified

From tendon geometry to long-term response

PTKalc uses the equivalent load method for prestress and a two-pass effective-stiffness finite-element procedure for long-term serviceability analysis.

Prestress actions

Curved tendon profiles are converted into equivalent distributed and concentrated loads, allowing prestress to enter the same global finite-element model as gravity loading.

Ultimate design

Flexural and shear design results are checked using the resulting structural actions together with the local contribution of prestressing to section behaviour.

Long-term deflection

Cracking is assessed locally, effective stiffness is established along the member, and the structure is re-analysed using the resulting spatially varying flexural rigidity.

Read the PTKalc methodology

Ongoing verification

Contribute a PTKalc benchmark example

RKALC welcomes independent comparison examples covering post-tensioned beams, band beams and other practical structural arrangements. Contact RKALC before commencing so the benchmark scope, modelling assumptions and comparison method can be agreed.

Contact RKALC