3309.4.1 Additional safeguards during excavation.
BC § 3309.4.1
The following additional requirements shall apply during excavation: 1. The person causing the excavation shall support the vertical and lateral load of the adjoining structure by proper foundations, underpinning, or other equivalent means where the level of the foundations of the adjoining structure is at or above the level of the bottom of the new excavation.
2.Where the existing adjoining structure is below the level of the construction or demolition, provision shall be made to support any increased vertical or lateral load on the existing adjoining structure caused by the construction or demolition.
3.Where the construction or demolition will result in a decrease in the frost protection for an existing foundation below the minimums established in Section 1809.3.1, the existing foundation shall be modified as necessary to restore the required frost protection.
