Evaluating the safe interim use of seismically deficient buildings

Abstract

SummaryHow long can a seismically deficient building be used until the seismic risk becomes too high to be acceptable? A model interim use plan is developed with requirements to abandon the building if retrofit is not completed in the use period. Acceptable seismic performance is keyed to American Society of Civil Engineers (ASCE) 41 levels. The acceptable occupancy or use period is limited to that which results in the same probability of performance as stated for an ASCE 7‐16–compliant building, except that the total risk in the use period is due to all possible earthquakes impacting the site, not just the maximum considered earthquake. The Thiel–Zsutty damage model is used to determine the probabilities for assigned threshold ranges where unacceptable performance can occur. Other response prediction models can be used if they provide an annual probability of a given performance level exceedance. Example applications are given for both marginally and highly deficient buildings located at 17 national sites in high and moderate seismic hazard regions and include ASCE 7 Risk Class I–IV buildings. This approach may be applied to any risk decision‐making issue for which there is an annual probability of damage exceedance.