Commentary on FEMA P‐807 for Retrofit of Wood‐Frame Soft‐Story Buildings

The FEMA P‐807 guideline titled Seismic Evaluation and Retrofit of Multi‐Unit Wood‐Frame Buildings with Weak First Stories is a new approach for building retrofit. It goes beyond current building codes and standards by quantifying performance in probabilistic terms. The authors performed an independent review of P‐807, and the resulting commentary herein covers five topics: (1) building lateral force‐drift (backbone) curves, (2) building interstory drift limits, (3) lateral strength requirements, (4) collapse safety margins, and (5) site class effects.

It was concluded that P‐807 may be an efficient way for relative ranking and selection of retrofit designs—but it has questionable accuracy for predicting actual building performance (i.e., the probability that a particular seismic intensity will result in a meaningful state of damage for a specific building).