Table 8-1.3
OSHA Requirements (Minimum) for Trench Shoring
Size and Spacing of Members
Cross Braces1
Uprights
Stringers
Maximum Spacing
Width of Trench (feet)
Depth of Kind or Condition
Trench
of Earth
Vertical Horizontal
Minimum Maximum Minimum Maximum
Up to 3 4 to 6 7 to 9 10 to 12 13 to 15
Dimension Spacing Dimension Spacing
Feet
Inches
Feet
Inches
Feet
Inches Inches Inches. Inches Inches
Feet
Feet
5 to 10
Hard, compact
3 x 4 or 2 x 6
6
--
--
2x6 4x4 4x6
6x5
6x8
4
6
Likely to crack
3 x 4 or 2 x 6
3
4x6
4
2x6
4x4
4x6
6x6
6x8
4
6
Soft, sandy, or filled 3 x 4 or 2 x 6
Close
4x6
4
4x4
4x6
6x6
6x8
8x8
4
6
Sheeting
3 x 4 or 2 x 6
6x8
4
4x4
4x6
6x6
6x8
8x8
4
6
Hydrostatic
Close
Pressure
Sheeting
11 to 15
Hard
3 x 4 or 2 x 6
4
4x6
4
4x4
4x6
6x6
6x8
8x8
4
6
Likely to crack
3 x 4 or 2 x 6
2
4x6
4
4x4
4x6
6x6
6x8
8x8
6
Soft, sandy or
3 x 4 or 2 x 6
Close
4x6
4
4x6
6x6
6x8
8x8
8 x 10
4
6
Filled
Sheeting
Hydrostatic
3x6
Close
8 x 10
4
4x6
6x6
6x8
8x8
8 x 10
4
6
Pressure
Sheeting
16 to 20
All kinds or
3x6
Close
4 x 12
4
4 x 12
6x8
8x8
8 x 10 10 x 10
4
6
Conditions
Sheeting
Over 20
All kinds or
3x6
Close
6x8
4
4 x 12 8 x 8 8 x 10 10 x 10 10 x 12
4
Conditions
Sheeting
1
Trench jacks may be used in lieu of, or in combination with, cross braces. Where desirable, steel sheet piling and bracing of equal strength
may be substituted for wood.
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