Reliability-Based Shear Rating of Prestressed Concrete Bridge Girders Considering Capacity Adjustment Factor

Abstract

In this study, the reliability of prestressed concrete (PC) bridge girders in the shear rating process is quantified, in which the use of a simple procedure to enhance the accuracy of shear capacity evaluation for rating is evaluated. It was found that the approximate methods used in code-based procedures to develop shear resistance used for reliability calibration of existing code standards result in larger discrepancies in reliability than previously assumed, as well as substantially conservative shear capacity evaluation in most cases. To examine the effects of using a more accurate shear rating process, a selection of typical PC bridge girders designed and rated for Michigan legal loads is considered as an example. For the example girders, use of existing methods resulted in some reliability indices below the required levels. However, use of the more accurate procedure resulted in shear reliability indices that met the target reliability index, thus preventing unnecessary traffic restrictions as well as avoiding potentially rating structures unconservatively.