Sheet C-105
Excavation & Earth Retentionconcept
Excavation bracing: crosslot struts vs tiebacks and rakers
One-line orientation
A shoring wall needs bracing against earth pressure. Crosslot struts and rakers occupy the excavation; tiebacks extend into the soil behind the wall and keep the excavation more open.
Key points
- Bracing supports the shoring wall against lateral earth (and water) pressure; it is not the wall itself.
- Crosslot bracing: horizontal struts span across the excavation, propping opposite shoring walls against each other. Effective, but the struts occupy the open cut.
- Tiebacks: anchors drilled into soil/rock behind the wall and tensioned to hold the wall back. They keep the excavation clear of internal obstructions.
- Rakers: inclined supports set against the shoring panels from inside the cut, bracing the wall diagonally down to a base/footing.
- Selection logic: crosslot suits narrower cuts where spanning is practical; tiebacks suit wide or busy excavations where a clear work area matters (no struts in the way).
Confusions / comparison
| Crosslot struts | Tiebacks | Rakers | |
|---|---|---|---|
| Where it acts | Spans across the cut | Behind the wall (into soil/rock) | Diagonal, inside the cut |
| Load goes to | Opposite shoring wall | Tensioned soil/rock anchors | Interior footing/base |
| Excavation clear? | No — struts obstruct | Yes — open work area | Partly — diagonals inside |
| Good when | Narrower cuts | Wide / busy sites | When neither full-span nor anchors suit |
Related
→ Shoring systems (this module): the walls being braced · Angle of repose (this module): why shoring + bracing is needed instead of a laid-back slope · Underpinning (this module): protecting adjacent foundations during deep excavation.
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