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Hydraulic Cylinder Specifications

Commonly, hydraulic cylinders for aluminum shoring systems come in either 2" or 3" sizes. The
2" cylinders must have a 2" inner diameter and a safe working capacity of at least 18,000 pounds
axial compressive load, and the 3" cylinders must have a 3" minimum inner diameter and a 30,000
minimum axial compressive load strength. In some cases, steel oversleeps are required for
additional protection against buckling.

Applicability of OSHA Tables

The tables in Appendix D do not apply when:

• A vertical load more than 100 pounds exists in the middle of a hydraulic cylinder

• A surcharge load of 20,000 pounds from equipment adjacent to the trench is present

• The aluminum shoring system is being used in conjunction with a sloping system whose
slope is steeper than 3H: 1V unless the shoring system is designed for the entire depth of
the trench

Aluminum shores can be used in either vertical or horizontal orientations. Each orientation
has its own requirements and will be discussed now.

Vertical Aluminum Shoring Systems
In TYPE A or TYPE B soils, vertical aluminum shoring can be used as a stand-alone system. No
uprights or walers are required. Plywood can be used to control local raveling. The horizontal
spacing between shores is unaffected by the presence or absence of plywood.

Shoring system configurations using aluminum shores in the vertical orientation are dependent
only upon the depth and width of the trench as is illustrated in Tables D-1.1 and D-1.2. As the
depth or the trench increases, the distance between shores decreases. As the cylinder span
(trench width) increases, the size and strength of the cylinder increases as well. The vertical
shores must be spaced evenly throughout the trench.

THERE MUST BE A MINIMUM OF 3 SHORES IN THE TRENCH REGARDLESS OF
THE TRENCH LENGTH. Always follow manufacturer’s tabulated data.

The following is a summary of information for vertical aluminum shoring systems:

• Distances are measured center-to-center
• No fewer than three equally spaced shores in a group in the trench
• Top cylinders must be placed between 6 and 18 inches from the top of the trench

• Maximum distance from bottom cylinder to the bottom of the trench is 4 feet
• Vertical shoring uprights must have section modules of at least 0.40 inch

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