Strength evaluation of deteriorated girder ends. I: Experimental study on naturally corroded I-beams

Abstract

Corrosion is a common cause for steel bridge deterioration, primarily attributed to malfunctioning deck expansion joints. Aged joints fail to prevent water or deicing mixtures from penetrating into the bearing area triggering a corrosive process which locally damages the steel beams. Topologically non-uniform and highly uncertain, the appearance of corrosion makes the residual bearing capacity quite challenging to be accurately assessed by inspectors and engineers. The present study, the first part of a companion set of two papers, aims to evaluate and improve the efficiency of current strength assessment policies for un-stiffened rolled I-beams, based on field corroded girders tested in the laboratory. A total of six full scale loading tests are reported on naturally corroded girders, which were extracted from structurally deficient bridges in the state of Massachusetts. The test results indicate that provisions underestimate the capacities of five out of the six specimens, while the sixth test highlights the harmful effect of a web's deviation from plumbness. An alternative load path is also revealed for specimens with holes extending along the bottom at the girder web.