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157 Excavation Safety: Basic
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Other Safety Precautions

The OSHA standard requires you to provide support systems such as shoring, bracing, or underpinning to ensure that adjacent structures such as buildings, walls, sidewalks, or pavements remain stable.

There is no support system in the trench next to the adjacent structure. A worker in this trench was earlier buried up to his waist beneath collapsing concrete and brick veneer.

The standard also prohibits excavation below the base or footing of any foundation or retaining wall unless:

  • You provide a support system such as underpinning,
  • The excavation is in stable rock, or
  • A registered professional engineer determines the structure is far enough away from the excavation and the excavation will not pose a hazard to employees.

Excavations under sidewalks and pavements are prohibited unless you provide an appropriately designed support system or another effective means of support. There must not be any indications of a possible cave-in (while the trench is open) below the bottom of the support system. Also, you must coordinate the installation of support systems closely with the excavation work.

Once the work is finished, you are required to backfill the excavation when you take apart the protective system. After the excavation is cleared, remove the protective system from the bottom up. Make sure you are careful! In the next section, you'll learn more about safely installing and removing protective systems.

Knowledge Check Choose the best answer for the question.

2-3. What does OSHA require to make sure buildings, walls, sidewalks and pavements remain stable?