# Masonry Tie Bar Length Calculator

Total length, count and weight, with seismic embedment rules.

- Page: https://jianzhujisuan.com/en/tie-bar-length
- Category: Masonry (https://jianzhujisuan.com/en/c/masonry)
- Chinese version: https://jianzhujisuan.com/zh/tie-bar-length.md
- Data checked: 2026-10-25

## Quick result

With the default inputs (Wall thickness 240 mm, Seismic intensity 7 (≥1000 mm into wall), Wall segment length 4 m, Anchorage into column 200 mm, Bar diameter 6 mm, Vertical spacing 500 mm, Wall height 3 m, Bars per course 2 pcs): **Total length per tie bar 1238 mm**

## Inputs

| Parameter | Type | Default | Unit | Note |
|---|---|---|---|---|
| Wall thickness | number | 240 | mm |  |
| Seismic intensity | select | 7 (≥1000 mm into wall) | — |  |
| Wall segment length | number | 4 | m |  |
| Anchorage into column | number | 200 | mm |  |
| Bar diameter | number | 6 | mm |  |
| Vertical spacing | number | 500 | mm |  |
| Wall height | number | 3 | m |  |
| Bars per course | number | 2 | pcs |  |

## Formula

- **Intensity 6-7: embed ≥ max(1000 mm, wall/5)**: 
- **Intensity 8-9: embed ≥ max(700 mm, wall/5)**: 
- **Total = embed + anchorage + hook**: hook 6.25d
- **Count = (height ÷ spacing + 1) × bars per row**: 

## Worked example

240 mm wall, intensity 7, 4 m long, 3 m high, 200 mm anchorage, Φ6 at 500 mm with 2 bars per row: embedment max(1000, 800) = 1000 mm plus 200 anchorage and a 37.5 mm hook gives 1237.5 mm per bar; 7 rows means 14 bars, 17.3 m and 3.8 kg.

## Questions

### Why must the tie extend a metre into the wall?

The tie anchors the infill to the frame so it cannot fall outward in an earthquake. One metre provides enough bond with the masonry to hold the panel; shorter ties pull out once the wall cracks and the panel still collapses. This detailing was learned repeatedly from the Tangshan and Wenchuan earthquakes.

### Post-installed bars or cast-in starter bars?

Cast-in starters are more reliable (formed in one pour, no adhesive durability question) but awkward on site and easily bent during formwork. Post-installed bars are convenient and accurately positioned, but depend heavily on hole depth, cleaning and adhesive quality, so pull-out testing is mandatory - typically 1% of each batch, minimum three bars.

### Why three bars for 240 mm walls?

To spread the anchor points across the thickness. With only two bars near the middle, the masonry faces are poorly restrained and can split through the thickness in an earthquake. Three bars - one central and one near each face - confine the full depth. At 120 mm, two suffice.

## Related tools

- [Brick Wall Calculator](https://jianzhujisuan.com/en/brick-count): Pick a wall thickness, enter length and height, deduct openings, and get brick count plus mortar volume.
- [Mortar Calculator](https://jianzhujisuan.com/en/mortar): Choose brickwork or plastering, enter area and thickness, and get mortar volume plus cement and sand quantities.
- [AAC Block Quantity Calculator](https://jianzhujisuan.com/en/aac-block): Block count, volume and adhesive from wall size and block format.
- [Hollow Brick Quantity Calculator](https://jianzhujisuan.com/en/hollow-brick): Brick count, mortar volume and bricks per m³ from wall thickness and format.
- [Masonry Mortar Mix Calculator](https://jianzhujisuan.com/en/masonry-mortar-mix): Cement, sand and water for M5-M15 mortar by volume, with a batch sheet.
- [Masonry Tie Bar Calculator](https://jianzhujisuan.com/en/tie-bar): Tie bar count, weight, holes and resin from wall and spacing.

---

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