Components, systems and materials › Slope protection and rockfall › Reno mattress
Reno mattress
What it is
A reno mattress is a thin, wide gabion, typically about 0.17 to 0.3 m deep, laid flat to line channels and protect banks and beds from scour.
Where it is used
Canal and drain linings, river banks, spillway aprons, culvert inlets and outlets, and bridge pier scour protection.
How it works
The mattress spreads over the soil like an armoured blanket. Its stone fill resists flowing water, while the mesh holds stones that a free rip-rap layer would lose. Being flexible, it follows settlement and scour holes without breaking.
Types
- Standard reno mattresses
- mattresses with polymer-coated wire for submerged use
- launching aprons that fold down as scour develops
Materials
Coated steel mesh and stone fill sized to the mattress thickness, over a geotextile or graded filter.
Thickness and stone size are chosen from the flow velocity and shear stress. A filter beneath stops soil being washed out from under the mattress, which is the commonest cause of failure.
Installation and QA steps
- Trim the slope or bed to line
- Place filter
- Assemble and lace mattress units
- Fill with stone and close lids
- Anchor at the top of slope and key into the toe
- No filter so soil is pumped out
- Velocity beyond the design value
- Toe not keyed in, so the mattress slides
Codes cited
- ASTM A975 (USA): Double-twisted hexagonal mesh gabions and revet mattresses.
Cited by number only. We do not reproduce code text, tables or figures.
Related
Generic description for education. We do not name, endorse or compare manufacturers or products.
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