3304.4.1 Support of Excavation

The sides of all excavations, including related or resulting embankments, that are 5 feet (1524 mm) or greater in depth or height shall be supported in accordance with one or more of the following means. Where required by Section 3304.2, such means shall be indicated on drawings:

1. Sheeting, shoring, bracing, or by other retaining structures as may be necessary to prevent the sides of the excavation from caving in before permanent supports are provided. Such methods of protection shall be subject to special inspection in accordance with the provisions of Chapter 17; or
2. Excavation sides sloped not steeper than 45 degrees (0.79 rad) or stepped so that the average slope is not steeper than 45 degrees (0.79 rad) with no step more than 5 feet (1524 mm) high, provided such slope or step does not endanger any structure or temporary construction, including subsurface structures. Slopes or steps steeper than 45 degrees (0.79 rad), or steps more than 5 feet (1524 mm) high shall be permitted only where the registered design professional preparing the drawings required by Section 3304.2 determines, based upon the completion of a geotechnical investigation report acceptable to the commissioner, that the slopes or steps will be stable.

Exception: For a rock cut excavation, no protection is required, provided a registered design professional determines the rock cut will not be subject to shearing and will not otherwise be unstable before permanent supports are provided. Otherwise, the rock cut shall be stabilized in accordance with drawings prepared by the registered design professional.