NEHRP Clearinghouse

Title
Determination of the Failure Probability of One or More Structures Located at a Site. Seismic Design Decision Analysis.
File
PB293927.pdf
Author(s)
McMahon, P.
Source
National Science Foundation, Washington, DC. Applied Science and Research Applications., May 1975, 28 p.
Identifying Number(s)
INTERNAL STUDY-56
Abstract
Using the resistance curves developed for the failure of a single structure, this report also investigates the probability of 1 out of 100 structures failing. An attempt is also made to determine how well damage can be predicted when instead of a known resistance function, just the mean and variance of resistance are given. That is, a specific distribution is not known for the resistance of a structure. These various formulations are discussed. This report deals with only a two damage state situation, either failure or non-failure. Therefore, the results are only useful in predicting whether one of these two damage states will occur, not the probabilities of different levels of damage occurring. The main purpose of this report was to investigate the effects of a probabilistic resistance function, as opposed to a deterministic resistance, in predicting damage. The conclusion is that the probabilistic analysis lowers the overall risk in a manner that is shown in this report. When the resistance function is known, the results are quite useful and by inspection of the graphs and tables in this report the magnitude of the effect of the probabilistic approach can be seen. The conclusion drawn from the calculations when only the mean and variance of the resistance are known is that without any assumption about the resistance distribution, one can do no better than to establish a broad range for the probability of failure.
Keywords
Numerical analysis; Probability theory; Seismic design; Earthquake resistant structures; Damage assessment; Failure; Risk analysis; Seismic risk; Earthquake engineering; Earthquakes