10. Using Trench Cages

• Cages must be designed and approved by a professional engineer.
• Usual design criteria
  • 75 pounds/square foot/foot of depth
• Cages that are stacked must be secured to be able to transmit loading conditions from one cage to the other.
• Cages must have continuous sides.
• Cage sides must extend 2′ above the vertical wall of the excavation.
• If workers are to remain in the cage when it is dragged, there must be some sort of protection against rigging failure.
• No worker is to work outside the protection of the trench cage.