8. Trench Shoring Tables

Trench shoring table for trenches up to 5 feet wide

Trench shoring table for trenches up to 1.5 meters wide

Notes to Trench Shoring Tables

  1. In loose soils over 10' (3m), use Vee trench with side walls sloped at 45° or use semi-vee with a trenchcase.
  2. Wood shoring must be SPF Species D, Aspen Species Group F, #2 Grade or better. Tables are based on graded nominal lumber dimensions. Ungraded full dimension poplar is considered equal.
  3. Trenches less than 5' (1.5m) deep must be shored when dangerous ground movement is likely (hydrostatic pressure, vibration, etc.)
  4. Two struts must be installed on each vertical plane where struts required.
  5. Shoring for sand or gravel (loose/soft soils) may be sized for 'soils likely to crack/crumble'.
  6. Steel trench jacks can be substituted for wood struts as below, jacks must have end bearing area equal to wood struts.
Imperial Metric
Strut Size Pipe I.D. Size Strut Size Pipe I.D. Size
4" x 4" 1½" Standard 89 mm x 89 mm 40 mm Standard
4" x 6" 2" Standard 89 mm x 140 mm 50 mm Standard
6" x 6" 2" Standard 140 mm x 140 mm 50 mm Standard
6" x 8" 3" Standard 140 mm x 191 mm 75 mm Standard
8" x 8" 3" Standard 191 mm x 191 mm 75 mm Standard