Regression-Based Adjustment Factor to Better Estimate Shear Capacity for Load-Rating Simple Span PC Girders

Abstract

In this study, an adjustment factor was developed to better estimate the shear capacity of simple span prestressed concrete (PC) girders, for intended use in load rating. The adjustment factor is expressed as a function of several critical girder parameters including concrete strength, prestress level, stirrup spacing, and girder height. The adjustment factor was determined from a regression analysis of over 2 shear capacity results. The database was obtained from a parametric analysis conducted with a finite-element model validated with experimental data. Three different code methods were considered for comparison. Generally, code results were found to be inconsistently conservative. Application of the adjustment factor to an established procedure produced improvement in the accuracy and consistency of shear capacity estimation over existing code methods for the range of girder parameters considered. In addition, potential effects on rating factors for inventory and operational levels were quantified.