San Francisco County Municipal Code Ch. 8 Alterations – Level 2

805 Add the following section: 805.2.1 Substantial structural alteration. Where work involves a substantial structural alteration, the lateral load-resisting system of the altered building shall satisfy the requirements of Sections 1609 of the San Francisco Building Code and section 304.3.2 of this code. Where the building is assigned to Seismic Design Category D or F, supports and attachments for nonstructural components required to serve any portion of the building with a use included in Risk Category IV shall comply with Section 1613 of the San Francisco Building Code or shall comply with ASCE 41 using an objective of Position Retention nonstructural performance with the BSE-1E earthquake hazard level. Exceptions: 1. Buildings of Group R occupancy with not more than five dwelling or sleeping units used solely for residential purposes that are altered based on the conventional light-frame construction methods of the San Francisco Building Code. 2. Where the intended alteration involves structural components of only the lowest story of a building and Chapter 10 does not apply, the lateral load-resisting system above that story need not comply with this section.