Bench cut

  1. Definition & Purpose 

Overview

  • A bench cut is a section of trail tread which cuts into and across the side of a hill. 
  • It is broken down into the ‘Trail Tread’ and the ‘Backslope’. 
  • In this context, the Trail Tread has two distinct types: ‘Full Bench Cut’ and ‘Half Bench Cut’ (occasionally referred to as ‘Cribbed Bench’.
  • For both types of Trail Tread, care must be taken to ensure an appropriate cross slope (out slope, in slope) to control the water which is expected to run down the trail. For more information see Trail Tread section (to be developed).

Full Bench Cut

  • Complete width of the trail is dug into the slope.
  • Generally, a “Full Bench” construction should be preferred because this method is more stable, sustainable and requires less maintenance.
  • The disadvantage with this method is that the larger cut induces higher backslopes, which in steep terrain can be hard to blend with the natural slope.

Half Bench Cut (Cribbed Bench)

  • Part of the path width is dug into the slope, the other part is built up on the valley side and stabilised.
  • Mainly used in steep terrain (>80 %) or for crossings directly below obstacles (see figure 2-3).
  • The fill material used to build the alignment must be very well compacted and secured with valley side retaining walls (Preferably using rocks). 
  • Downstream embankments/berms may be created with the same process.
  • The disadvantage with this method is that it can be very challenging to sustain the width of the trail tread with the likelihood being that no matter how much you compact the material into the bench ‘shape’ it will always want to descend down into the slope.

Backslope

  • A bench cut should be constructed with a backslope. 
  • A backslope should be built to blend with the prevailing slope. 
  • Allowing soil to stabilise and vegetation to grow – reducing erosion and creating a more natural trail feeling. 
  • Allows the rider to be more in the centre of the trail where the tread is most durable, rather than being pushed to the edge. 
  • Machine Build & Engineered Trails: serves as a safe platform for working with machinery while building the trail. 

2. Key Considerations

2.1 Typical Characteristics

backslope

Figure 1: Full bench cut construction. Source: IMBA 2017

Figure 2: Cribbed bench trail, source: Felton 2004, trail solutions

Figure 3 – Cribbed bench construction (sources IMBA)

Figure 4: Typical trailway cross sections, Full bench and partial bench
source : https://www.fs.fed.us/t-d/pubs/htmlpubs/htm00232839/page05.htm#figure10 (redesign by Bikeplan)

2.2 Key Aspects

 

3. Building Tips

Figure 5: Flagging and building a full bench tread (source: Felton 2004, trail solutions, IMBA’s guide to building sweet singletracks)

4. Media

See media library for more media files

 

5. References

  1. Felton, V. (2004). Trail Solutions: IMBA’s Guide to Building Sweet Singletrack (IMBA (International Mountain Bicycling Association), Ed.). International Mountain Bicycling Association.
  2. International Mountain Bicycling Association. (2001). Building Better Trails: Designing, Constructing and Maintaining Outstanding Trails.
  3. International Mountain Bicycling Association (IMBA). (2017). Guidelines for a Quality Trail Experience: mountain bike trail guidelines. The Bureau of Land Management (BLM. https://www.blm.gov/sites/blm.gov/files/Guidelines-for-a-Quality-Trail-Experience-2017.pdf

 

6. Further reading

Part 6, page 141

  • IMBA (2001). Building Better Trails: Designing, Constructing and Maintaining Outstanding Trails –

Chapter trail construction page 26

Chapter 4 Creating Trails and Trail Features – Page 45