Tall Column Reliability under Nonstationary Loads: Model Formulation

Abstract

The reliability of tall cantilever structures subjected to earthquake loads is evaluated using a stochastic dynamic response model. Since tall columns are typically very slender, the model considers the effects of both vertical and horizontal acceleration. Failure is defined as the crossing of the response process over a member strength threshold. The stochastic response model determines both the duration of shaking and the probability distribution for the time to failure. The limit‐state equation then compares the time to failure to the duration of motion. To illustrate the model, the reliability of a typical distilling column from an oil refinery is investigated for two limit states, yielding of the anchor bolts and buckling of the supporting skirt. The results show that the anchor bolts are likely to yield before the skirt buckles, thus providing an energy absorbing mechanism against buckling failure.