Infrastructure Technology Institute
The latest meeting of the ITI-sponsored Midwest Bridge Working Group (MBWG) was held in December 2008 in Louisville, Kentucky. The forum attracted over 120 bridge professionals from state highway agencies, consulting firms, vendors, and universities for one and a half days of discussion of best practices and technical, political, and financial issues in the field of bridge maintenance and inspection.
The day-long first session included a wide variety of talks on new technology and methodology for bridge inspection and maintenance. One notable presentation was an extensive explanation of Missouri’s Follow-Up Action Required procedure by Ken Foster, who recently joined the staff of the Federal Highway Administration after a long career with the Missouri DOT. Mr. Foster explained that the procedure enables inspectors to report bridge problems or deficiencies which require immediate investigation or
The development of the process in 2003 was prompted by a group of inspectors who found that certain potentially critical bridge problems never seemed to be remedied in spite of inspectors’ reporting them after every inspection. Under the Follow-Up Action Required procedure, inspectors submit a form documenting an issue of particular concern (including photographs and other documentation) along with a recommended plan of action for review by an engineer. If the issues is deemed a Critical Inspection Finding (CIF) in need of immediate attention, inspectors and engineers then work together to develop a response plan. Because the new procedure ensures timely and thorough response to inspection results, the number of CIFs in the first year of the program dropped from 15 to 2, and there have been no more than four CIFs in each of the subsequent years.
Another highlight of the day was a discussion on fracture critical bridge inspection timetables delivered by Professor Rob Connor of Purdue University.
Prof. Connor discussed H.R. 3999, the National Highway Bridge Reconstruction and Inspection Act of 2008, which will require engineers to perform a hands-on inspection of fracture critical bridges at the same time every year. He argued that this method is both inefficient and inadequate for ensuring the safety and serviceability of critical structures, particularly since it may result in some structures being over-inspected due to strict calendar requirements while others are under-inspected due to lack of resources. Prof. Connor suggested that the calendar-based inspection schedule currently mandated by federal law should be replaced with performance-based inspection scheduling with an engineering approach similar to that used in aerospace and other industries, allowing engineers to allocate resources where they are most needed.
Two ITI researchers gave presentations in the afternoon. Chief Research Engineer Daniel Marron spoke about noise localization on a new rolling-bascule lift bridge. Mr. Marron’s talk drew on ITI’s years of experience and pioneering work in the application of acoustic emission (AE) testing – a non-destructive evaluation technique which employs special transducers to “listen” to ultrasonic noises made by engineering materials under stress - to large civil structures, particularly steel highway bridges. In this case, the ITI team was able to locate the source of loud banging noises that occurred during movement of the bridge. David Corr, Clinical Associate Professor of Civil Engineering and the newest member of the ITI team, discussed lessons learned from the collapse of the Marcy Bridge in upstate New York during construction. Prof. Corr’s presentation concentrated on the application of finite element models to investigate the collapse.
The morning-long second session of the working group meeting was a two-part discussion for all participants, including an open discussion of general inspection and maintenance issues and a forum in which participants shared agency successes and best practices. Scott Stotlemeyer of Missouri DOT moderated the early session and began the dialogue with talk of the effect of funding shortages in the current economic climate. David Steele of the Kentucky Transportation Cabinet moderated the late morning session, beginning with a success story about the emergency replacement of a small bridge in the coal mining region of southeast Kentucky.
MBWG, which has been supported by the Infrastructure Technology Institute since 1996, continues to be a successful forum for the interchange of information between participating state highway agencies on issues related to bridge inspection and maintenance. ITI works closely with the Kentucky Transportation Center (KTC) and the University of Kentucky (UK) Civil Engineering Department to facilitate Working Group activities.