POL Government Elected Officials Auditor Hull Caballero Charter, Code & Policies City Code & Charter Online Code & Charter Title 24 Building Regulat Chapter 24.85 Seismic Design Requirements for Existing Buildings
24.85.050 Building Additions or Structural Alterations.

(Amended by Ordinance No. 178831, effective November 20, 2004.) An addition that is not structurally independent from an existing building shall be designed and constructed such that the entire building conforms to the seismic force resistance requirements for new buildings unless the three conditions listed below are met. Furthermore, structural alterations to an existing building or its structural elements shall also meet the following three conditions:
A. The addition or structural alteration shall comply with the requirements for new buildings;
B. The addition or structural alteration shall not increase the seismic forces in any structural element of the building by more than 5 percent unless the capacity of the element subject to the increased forces is equal to or greater than that required for new buildings. Multiple force increases on an element are allowed provided the cumulative force increase does not exceed 5 percent of the force on the element from its original, unaltered state; and
C. The addition or structural alteration shall not decrease the seismic resistance of any structural element of the existing building unless the reduced seismic resistance of the element is equal to or greater than that required for new buildings.

Title 24 Building Regulat
Chapter 24.10 Administration and Enforcement
Chapter 24.15 Definitions
Chapter 24.20 Special Inspections
Chapter 24.25 Movings of Buildings
Chapter 24.30 Home Occupations
Chapter 24.35 Historical Buildings
Chapter 24.40 Use of and Projections Over Public Streets and Property
Chapter 24.45 Parking and Driveway Surfaces
Chapter 24.50 Flood Hazard Areas
Chapter 24.51 Wildfire Hazard Zones
Chapter 24.55 Building Demolition
Chapter 24.60 Fences
Chapter 24.65 Sidewalk Vault Openings
Chapter 24.70 Clearing and Grading
Chapter 24.75 Uniform Building Address System
Chapter 24.80 (Repealed)
Chapter 24.85 Seismic Design Requirements for Existing Buildings
Chapter 24.90 Manufactured Dwelling Installation and Accessory Structures, Manufactured Dwelling Parks, Recreation Parks, Recreational Park Trailer Installation and Accessory Structures
Chapter 24.95 (Repealed)