Lesson 4 of 6
Resolve column ties and leg arrangements
Translate a leg count into physical closed ties and cross-ties, and recognise when the drawing must be reviewed instead of guessed.
This builds on Lesson 3, where we worked out bar count, total length and steel weight — go back to Lesson 3.
- 1Count physical pieces
- 2Measure each shape separately
- 3Know when to stop calculating
- 4Your turn
Learn · Part 1
Count physical pieces
A leg count is not a count of closed rectangles. Select an arrangement.
2 legs
0 cross-ties per level
The course convention uses one closed rectangle plus 0 cross-ties. Each green cross-tie hooks around a longitudinal bar at both ends. Grey dots are longitudinal bars seen in section. These are example positions, not a reinforcement design; confirm the drawing’s arrangement and direction.
3 legs
1 cross-ties per level
The course convention uses one closed rectangle plus 1 cross-ties. Each green cross-tie hooks around a longitudinal bar at both ends. Grey dots are longitudinal bars seen in section. These are example positions, not a reinforcement design; confirm the drawing’s arrangement and direction.
4 legs
2 cross-ties per level
The course convention uses one closed rectangle plus 2 cross-ties. Each green cross-tie hooks around a longitudinal bar at both ends. Grey dots are longitudinal bars seen in section. These are example positions, not a reinforcement design; confirm the drawing’s arrangement and direction.
Learn · Part 2
Measure each shape separately
For this example only, cross-ties span the column width.
Closed rectangle
1,240 mm
The rectangular tie includes three corners and two hook bends, as in the stirrup lesson.
Cross-tie
330 mm
The outside-to-outside width is 220mm. Add two hooks and deduct two hook bends; there are no rectangle corners.
Learn · Part 3
Know when to stop calculating
Some drawings need clarification before a quantity is safe to report.
4-leg example
1,900 mm per tie level
One closed tie plus two width-spanning cross-ties, under the stated example arrangement.
6 legs, no detail
Needs review
A leg count alone cannot tell us the physical 6-leg arrangement. Request the tie detail; no length or zero quantity is supplied.
Apply what you learned
Your turn.
Under this course’s stated 4-leg arrangement, how many cross-ties accompany one closed rectangle at each level?
See the worked solution
One closed rectangle plus 2 cross-ties. Check the actual drawing before applying the convention.
Answer: 2 cross-ties.
Lesson notes & reference
Worked exampleThe worked closed tie is 1240mm; the width-spanning cross-tie is 330mm.
Your starting point
You already know how to calculate one closed loop. A column tie set may add straight cross-ties at the same level.
Read the complete lesson
1. Count physical pieces
A leg count is not a count of closed rectangles. Select an arrangement.
2 legs · 0 cross-ties per level
The course convention uses one closed rectangle plus 0 cross-ties. Each green cross-tie hooks around a longitudinal bar at both ends. Grey dots are longitudinal bars seen in section. These are example positions, not a reinforcement design; confirm the drawing’s arrangement and direction.
3 legs · 1 cross-ties per level
The course convention uses one closed rectangle plus 1 cross-ties. Each green cross-tie hooks around a longitudinal bar at both ends. Grey dots are longitudinal bars seen in section. These are example positions, not a reinforcement design; confirm the drawing’s arrangement and direction.
4 legs · 2 cross-ties per level
The course convention uses one closed rectangle plus 2 cross-ties. Each green cross-tie hooks around a longitudinal bar at both ends. Grey dots are longitudinal bars seen in section. These are example positions, not a reinforcement design; confirm the drawing’s arrangement and direction.
2. Measure each shape separately
For this example only, cross-ties span the column width.
Closed rectangle · 1,240 mm
The rectangular tie includes three corners and two hook bends, as in the stirrup lesson.
Cross-tie · 330 mm
The outside-to-outside width is 220mm. Add two hooks and deduct two hook bends; there are no rectangle corners.
3. Know when to stop calculating
Some drawings need clarification before a quantity is safe to report.
4-leg example · 1,900 mm per tie level
One closed tie plus two width-spanning cross-ties, under the stated example arrangement.
6 legs, no detail · Needs review
A leg count alone cannot tell us the physical 6-leg arrangement. Request the tie detail; no length or zero quantity is supplied.
The schedule you’re building toward
The same worked example throughout the course: three identical beams, with three bottom and three top main bars in each.
| Bar | Shape | Dia | Cutting length | Bars per member | Total bars | Total length | Weight | Notes |
|---|---|---|---|---|---|---|---|---|
| S1 | Stirrup · rectangular, 135° hooks | 8mm | 1220mm | 27 | 81 | 98.82m | 39.04kg | Uniform centres; no zones |
| B1 | Bottom main · straight | 16mm | 5500mm | 3 | 9 | 49.50m | 78.22kg | Straight anchorage at both ends |
| T1 | Top main · straight | 16mm | 5500mm | 3 | 9 | 49.50m | 78.22kg | Straight anchorage at both ends |
Total steel: 195.48kg. Worked quantities exclude wastage. Main bars assume straight anchorage fits each support; use the actual structural detail for a project.
You can quantify bars inside a member. How much extra length is needed where a main bar enters a support or exceeds stock length?
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