San Francisco County Municipal Code Part C Application of Asce 41-13 to Evaluation and Retrofit Design

DISCUSSION : Further development of this section is expected as needed to address issues specific to Chapter 5E. The sections outlined below cover broad issues consistent with Chapter 5E. Otherwise, use of this standard is subject to existing Department procedures for implementation of SFBC 104A.2.8, Alternate materials, design, and methods of construction. C1. Required scope of work

1. No nonstructural evaluation or retrofit is required.
2. Retrofit strength need not exceed 1.3 times the strength of the story above. Wherever the strength of two stories is being compared, an adequate load path must be assumed for all walls and partitions in the upper story.

Commentary: This requirement prevents underestimating the upper story strength. It will apply for calculations of weak story or soft story ratio in ASCE 31/41, CEBC Appendix A - Chapter A4, and other code-based procedures; application of the 1.3 cap on retrofit strength for ASCE 41 and CEBC Appendix A

• Chapter A4 retrofits; and calculation of spectral capacity with FEMA P-807.