Free post-tensioned slab calculator to SANS 10100
Checks one design strip of a post-tensioned flat slab with unbonded monostrand tendons, and draws the tendon profile. Free, no install, and prints a calc sheet with clause references.
No install, no card. The result shows without an account; a free account opens every check with its clause, the calc sheet and the bending schedule for 3 designs a month (one calculator, 24 hours). Calculator packs, coming soon, remove the limit.
What the calculator checks.
Every check is shown with the working, the clause and a pass or fail.
- Parabolic tendon profile with reverse curves over the columns, drape and balanced load per span
- Friction, draw-in, elastic shortening, relaxation, shrinkage and creep losses (SANS 10100-1 cl. 5.8)
- Average precompression and tendon spacing (ACI 318-19 cl. 8.6.2.1 and 8.7.2.3)
- Stresses at transfer and in service with the prestress moment, for patterns of imposed load (cl. 5.3.2)
- Ultimate flexure with unbonded tendons and bonded bars, including the secondary moments (cl. 5.3.3)
- Bonded bars at the columns, punching at interior and edge columns, deflection and anchorage-zone bursting steel
Codes: SANS 10100-1 section 5 (prestressed concrete), with ACI 318-19 for two-way prestressed slabs
A tool to check a design, not a design approval. Check the results and have the design signed by a registered professional engineer.
Short answers.
About this free calculator.
Is the post-tensioned slab calculator free?
Yes. It is free to use: enter your own values and every check shows on the page with its result.
Do I need an account?
No account is needed to use it: every check shows on the page with its result and clause, with a calc sheet summary. Without an account you see the result. A free STATIX account (email or Google, no card) opens every check with its clause, the full calc sheet to print or save as a PDF and the SANS 282 bending schedule for 3 designs a month (one calculator, open for 24 hours). Paid plans, coming soon, will make them unlimited.
Which code clauses does it use?
The calc sheet names the clause on every step: SANS 10100-1 cl. 5.8 for losses, cl. 5.3.2 for stresses, cl. 5.3.3 for ultimate flexure and cl. 5.8.5 for anchorage zones, and ACI 318-19 cl. 8.6, 8.7 and 22.6 for the flat-slab rules.
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