[BS] A304.2.2 Evaluation of Existing Foundations
Partial perimeter foundations or unreinforced masonry foundations shall be evaluated by a registered design professional for the force levels specified in Section A301.3. Test reports or other substantiating data to determine existing foundation material strengths shall be submitted to the building official. Where approved by the building official, these existing foundation systems shall be strengthened in accordance with the recommendations included with the evaluation in lieu of being replaced.
Exception: In lieu of testing existing foundations to determine material strengths, and where approved by the building official, a new nonperimeter foundation system designed for the forces specified in Section A301.3 shall be used to resist lateral forces from perimeter walls. A registered design professional shall confirm the ability of the existing diaphragm to transfer seismic forces to the new nonperimeter foundations.