PEER has just published Report No. 2015/01 titled “Concrete Column Blind Prediction Contest 2010: Outcomes and Observations” as a new addition to the PEER Report Series. It was authored by Vesna Terzic, Matthew J. Schoettler, Jose I. Restrepo, and Stephen A. Mahin.
Performance-based earthquake engineering is based on the premise that the performance of engineered facilities can be predicted and evaluated with sufficient confidence. Many current PBEE frameworks assume performance is evaluated with high confidence. However, prediction of system response greatly depends on the analyst’s experience and modeling skills. Therefore, the uncertainty with which the engineering community can predict response of a system or one of its components should be realistically quantified in PBEE. A blind prediction contest of a simple full-scale reinforced concrete bridge column exposed to six consecutive unidirectional ground motions was organized to identify the uncertainty with which important response quantities could be predicted. Predictions submitted by 41 teams were statistically analyzed and showed tremendous scatter in predictions of basic engineering response parameters. For instance, the average coefficients of variation in predicting maximum displacement and acceleration over 6 ground motions were 39% and 48%, respectively. Biases in median predicted responses were significant, varying from 5 – 35% for displacement and from 25% – 118% for acceleration. Although the results of this blind prediction contest provide the data regarding the modeling uncertainty of modern bridge columns, more than anything these results stress the need for a comprehensive analytical study with intent of generating guidelines on bridge column modeling with the goal of reducing the modeling uncertainty.