Title: Inelastic Shear Distribution in Prestressed Concrete Girder Bridges

Author(s): Benjamin Z. Dymond, Catherine E. W. French, Carol K. Shield

Publication: Symposium Paper

Volume: 342

Issue:

Appears on pages(s): 1-19

Keywords: shear distribution, inelastic behavior, failure, concrete bridge, load testing, prestressed concrete

DOI: 10.14359/51725934

Date: 6/1/2020

Abstract:
An experimental investigation was conducted on a full-scale prestressed concrete girder laboratory bridge to determine whether linear elastic shear distribution principles are conservative for load rating at ultimate capacity. A secondary goal was to determine whether existing web-shear cracks would be visible in an unloaded state. Two tests were conducted to failure (one near the end with a partial-depth diaphragm and one near the end without) to determine if the most loaded interior girder shed shear force to adjacent girders as it transitioned from uncracked to cracked to failure. Failure during each test was characterized by web-shear crushing and bridge deck punching at the peak applied load. Differences in the behavior of the two ends (with and without partial depth end diaphragm) affected the diagonal crack pattern, shear distribution, and loads at cracking and failure. The effect on loading was less than 10%. Inelastic shear distribution results indicated the girder carrying the most load redistributed shear to the other girders as it lost stiffness due to cracking. Use of linear elastic load distribution factors was conservative considering shear distribution at ultimate capacity. The visibility of web-shear cracks in an unloaded state was found to be a function of stirrup spacing.