Uniform spacing along a supported run
Supports are distributed evenly over the effective length (span minus end offsets).
| Case | Core equations |
|---|---|
| Effective length | L = Span − 2 × EndOffset |
| End supports included |
Segments = Supports − 1 Spacing = L ÷ Segments Position(i) = EndOffset + (i − 1) × Spacing |
| Interior supports only |
Segments = Interior + 1 Spacing = L ÷ Segments Position(i) = EndOffset + i × Spacing |
| Count from max spacing |
Segments = ceil(L ÷ MaxTarget) Spacing = L ÷ Segments |
| Simple load per support |
DesignLoad = TotalLoad × SafetyFactor LoadPerSupport = DesignLoad ÷ Supports |
This tool provides planning-level spacing. Always verify with drawings and shoring guidance.
Practical workflow
- Measure the total run that needs support.
- Set an end offset to avoid edge congestion.
- Select whether supports exist at both ends.
- Pick a sizing method: count-based or spacing-based.
- Add optional limits to highlight spacing warnings.
- Choose rounding that matches your field layout method.
- Press Calculate spacing to generate positions.
- Download the CSV or PDF for sharing.
Sample inputs and outputs
| Scenario | Span | End Offset | Method | Supports / Target | Resulting Spacing | Notes |
|---|---|---|---|---|---|---|
| Shoring under beam line | 6.0 m | 0.15 m | From count | 6 supports (ends included) | 1.14 m | Even layout across effective 5.70 m. |
| Temporary wall bracing | 24.0 ft | 0.5 ft | From max | Max 4.0 ft | 3.83 ft | Segments increased using ceiling rule. |
| Interior-only supports | 10.0 m | 0.25 m | From count | 5 interior supports | 1.58 m | Supports start one spacing after offset. |
Example values are illustrative and not a substitute for design checks.
How this spacing calculator supports field layout
Supplemental support posts are commonly arranged to distribute reactions more evenly and reduce localized overstress. This calculator converts a measured run into an effective length by subtracting two end offsets. For example, a 6.00 m run with 0.15 m offsets gives 5.70 m of working length. If you select 6 supports with ends included, the run is divided into 5 segments, producing 5.70 ÷ 5 = 1.14 m spacing before rounding.
Sizing by post count versus spacing target
Two sizing modes help different workflows. “Spacing from post count” is best when the number of available posts is fixed. “Post count from max spacing” is used when a maximum gap is required. With a 24.0 ft run and 0.5 ft offsets, the effective length is 23.0 ft. If the target is 4.0 ft, segments are ceil(23.0 ÷ 4.0) = 6, so spacing becomes 23.0 ÷ 6 = 3.83 ft.
Rounding for practical measurement
Layout often follows tape or laser marks, so spacing is rounded to a chosen step. A 0.01 m step supports fine layout, while 0.05 m or 0.10 m can be faster onsite. “Up” rounding reduces gaps and is typically the conservative choice when controlling maximum spacing. Optional minimum and maximum limits flag cases where rounded spacing falls outside your planning bounds.
End supports and interior-only configurations
When end supports are included, the first and last supports sit at the end offsets, and spacing is measured between adjacent supports. For interior-only layouts, supports begin one spacing after the first offset and stop one spacing before the far offset. This avoids congested ends while still maintaining regular segment lengths across the effective span.
Interpreting the load estimate
If you enter a total supported load, the calculator provides a simple equal distribution value. The reported design load is TotalLoad × SafetyFactor, then divided by the number of listed supports. This is a screening check only; final reactions depend on stiffness, tributary areas, and construction sequencing.
Frequently asked questions
1) What does “end offset” mean?
End offset is the clear distance from each end of the run to the first possible support location. It reduces edge congestion and keeps supports away from weak or obstructed ends.
2) When should I include end supports?
Include end supports when the run is intended to be supported at both ends of the effective length. Choose interior-only when ends are blocked by openings, anchors, or required clearances.
3) How does “post count from max spacing” work?
The calculator divides effective length by your max spacing target and rounds up to the next whole segment count. That guarantees the calculated spacing is at or below your target before rounding adjustments.
4) Which rounding mode is safest?
Rounding “Up” is usually conservative for spacing targets because it reduces the gap between supports. If you must round down for layout constraints, consider re-running with a smaller target maximum.
5) Why do I see spacing warnings?
Warnings appear when your rounded spacing falls outside optional minimum or maximum limits, or when rounding pushes spacing above your target maximum. Adjust the count, target, or rounding step to resolve.
6) Is the load per support output a design value?
It is a planning estimate only. The tool assumes equal load sharing and applies the safety factor. Real reactions vary with stiffness, connections, tributary width, and construction staging.
7) Why are CSV and PDF exports disabled until I calculate?
Exports are generated from the last successful calculation stored in the session. Run the calculator once to create a result set, then use the download buttons to save the report.