Sensitivity Analysis of Time-Dependent Behavior in PSC Box Girder Bridges

Abstract

This paper describes a method of statistical analysis and a sensitivity analysis of the effects of creep and shrinkage in prestressed concrete (PSC) box girder bridges. Three possible sources of the uncertainties of the structural response have been taken into account: creep and shrinkage model uncertainty, parameter variation, and environmental conditions. The statistical and sensitivity analyses are performed using the Latin hypercube sampling method. For each sample, a time-dependent structural analysis is performed to produce response data, which are then analyzed statistically. Two measures are examined to quantify the sensitivity of the outputs to each of the input variables. These are the partial rank correlation coefficient and the standardized rank regression coefficient computed on the ranks of the observations. To apply the proposed method to a real structure, the uncertainty and sensitivity of the time-dependent axial shortening of a PSC box girder bridge are analyzed. The results indicate that the creep model uncertainty factor and relative humidity appear to be the most dominant factors with regard to the model output uncertainty. The method identifies the most important factors in the long-term prediction of structural response in PSC box girder bridges and provides a realistic method to determine the uncertainty analysis of those structures.