Final Report Fhwa/in/jtrp-2001/10-ii Fatigue Behavior of Beam Diaphragm Connections with Intermittent Fillet Welds Part Ii: Brittle Fracture Examination of the I-64 Blue River Bridge

The contents of this report reflect the views of the authors who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Federal Highway Administration or the Indiana Department of Transportation. This report does not constitute a standard, specification, or regulation. This report is the third of a two-part, three volume final report presenting the findings of the research work that was undertaken to evaluate the behavior of Indiana highway bridges with diaphragm members welded directly to the web of the primary beams and girders. Fatigue cracks have been observed at several bridges that utilize the welded diaphragm connection. The seriousness of the cracking and the corresponding potential risk on the integrity of the bridge superstructure were assessed. Inspection and repair guidelines for bridges with welded diaphragm connections were also developed as part of the research effort. This volume presents the results of an evaluation of a brittle fracture crack that was discovered in one of the welded plate girder members of the I-64 Blue River Bridge in Harrison County of southern Indiana. The crack, which nearly severed the exterior girder on the northern side of the eastbound structure, was located in the middle span of the three-span bridge structure. The crack extended for most of the plate girder depth before it was arrested in the compression region near the top of the girder and the concrete deck. The primary purpose of the research study was to examine the causes of the brittle fracture of the I-64 Blue River Bridge girder. In addition to understanding the reasons for the brittle fracture, possible repair and retrofit procedures were formulated to improve the fracture resistance of bridges with details similar to the Blue River Bridge. Sincere thanks are also due to Mr. Albert Kovacs of Purdue University who oversaw the preparation and testing of the specimens for the materials evaluation. Appreciation is also extended to a number of individuals from Purdue University who provided enthusiastic and timely help for various aspects of the experimental and analytical portions of the study. Among them, in particular, are Mr. Harry Tidrick, Ms.