# Formwork Tie Calculator

Tie count, load per tie and diameter selection for wall formwork.

- Page: https://jianzhujisuan.com/en/formwork-tie
- Category: Temporary Works (https://jianzhujisuan.com/en/c/temporary-works)
- Chinese version: https://jianzhujisuan.com/zh/formwork-tie.md
- Data checked: 2026-10-25

## Quick result

With the default inputs (Wall length 15 m, Wall height 3 m, Horizontal spacing 0.6 m, Vertical spacing 0.6 m, Concrete pressure 50 kN/m² (typical)): **Number of ties 156 bars**

## Inputs

| Parameter | Type | Default | Unit | Note |
|---|---|---|---|---|
| Wall length | number | 15 | m |  |
| Wall height | number | 3 | m |  |
| Horizontal spacing | number | 0.6 | m |  |
| Vertical spacing | number | 0.6 | m |  |
| Concrete pressure | select | 50 kN/m² (typical) | — |  |

## Formula

- **Tie count**: n = (⌊L÷sh⌋+1) × (⌊H÷sv⌋+1)
- **Load per tie**: N = sh × sv × pressure
- **Selection**: N ≤ allowable (M12 12.9 / M14 20.3 / M16 30.0 / M20 47.4 kN)

## Worked example

A 15 m × 3 m wall at 0.6×0.6 m, 50 kN/m²: 26×6 = 156 ties, 0.6×0.6×50 = 18 kN each, M14 (20.3 kN allowable) is enough.

## Questions

### How is the pressure taken?

Fresh-concrete pressure depends on pour rate, temperature, slump and vibration, and is not simply γH. Low walls poured slowly press lightly (about 40 kN/m²); high walls, fast pours and pumping push it to 60-70 kN/m². A firm value follows a formula such as ACI 347 from height and rate; here the bands are for quick selection. Pressure is triangular with depth and peaks at the bottom, so tighten the lower rows.

### Must ties be sleeved?

Yes. A PVC sleeve lets the tie be pulled and reused, saving material and removing a corrosion path. Unsleeved ties stay in the wall; cut ends need corrosion treatment or rust travels inward along the tie and forms a water path, worst on external walls. Water-retaining parts (basements, tanks) need waterstop ties with a welded steel disc.

## Related tools

- [Scaffolding Calculator](https://jianzhujisuan.com/en/scaffolding): Enter the wall perimeter and scaffold height to get the area plus tube, coupler and board quantities.
- [Formwork Turnover Calculator](https://jianzhujisuan.com/en/formwork-turnover): Initial formwork area and replacement allowance from total area and cycles.
- [Full Scaffold Material Calculator](https://jianzhujisuan.com/en/full-scaffold): Standards, tube length and weight, couplers and board area.
- [Formwork Lateral Pressure Calculator](https://jianzhujisuan.com/en/formwork-pressure): Smaller of the two GB 50666 Annex A.0.4 expressions, plus head and critical rate.
- [Scaffold Tie Calculator](https://jianzhujisuan.com/en/scaffold-tie): Tie count from perimeter and height, with spacing limits checked.
- [Scaffold Dismantle Sequence Calculator](https://jianzhujisuan.com/en/scaffold-dismantle): Lifts to strip, allowable step height, and where the raking props start.

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Generated by BuildCalc. All calculations run in your browser; no data is uploaded. Formulas follow national standards and common trade practice; local codes govern.