Stability of Nearby Structures

Excavation operations can endanger the stability of adjoining buildings, walls, or other structures. Ensure the stability of such structures, as well as the protection of employees, by providing support systems such as shoring, bracing, or underpinning. Excavation below the level of the base or footing of any foundation or retaining wall that could be reasonably expected to pose a hazard to employees must not be permitted except in the following situations:

• A support system, such as underpinning, is provided to ensure the safety of employees and the stability of the structure.
• The excavation is in stable rock.
• A registered professional engineer has approved the determination that the structure is sufficiently removed from the excavation so as to be unaffected by the excavation activity and that such excavation work will not pose a hazard to employees.

Sidewalks and pavements and their associated structures must not be undermined unless a support system or another method of protection is provided to protect employees from the possible collapse of such structures.

To learn more about Trenching and Excavation visit our Trenching and Excavation Safety Online Training web page.