The finite element method is used to investigate failure mechanisms in pin-hanger connection in aging highway bridges. Bridge pins and hangers are typically considered as critical elements whose failure may result in partial or entire collapse of the structure. The primary function of a pin-hanger connection is to allow for...
The in-depth inspection by WIDOT detected two sites that had visible cracks in the stiffener-to-hanger diaphragm welds, the east side of Hanger 6 in the north tie girder, and the east side of Hanger 4 in the south tie girder. Additionally, many ultrasonic indications were detected by WIDOT in the...
This report describes the results of applying acoustic emission (AE) testing to the trunnion shafts of the East Span of the 1-5 Interstate Bridge. The tests were done at the request of Oregon DOT personnel to determine if active fatigue racks are present in the subject shafts.
The U.S. has 542,000 bridges that consume billions of dollars per year in construction, rehabilitation and maintenance funds and which are the lifelines of U.S. commerce. The 1992 ISTEA (fntermodal Surface Transportation Efficiency Act) mandates the implementation of a quantitative computerized bridge management system by I 996. A prime need...
Current bridge condition determination is based almost entirely on the use of visual inspection. This approach to bridge inspection provides data that is subjective and not traceable. Nondestructive evaluation (NDE) is a tool that in actuality is little used on bridges, but could eliminate much of the subjectivity of the...
This report shows the results of acoustic emission (AE) monitoring, and provides additional information on the nature of the ultrasonic indications in the north east trunnion shaft.
A remote global monitoring system is being operated on a 65 year old lift bridge in Sturgeon Bay Wisconsin. The system uses both strain gages and clinometers to continuously monitor the "health" of the fracture critical components of the bridge. Ruggedized miniaturized data loggers are locally mounted on the structure...
This technical report shows the findings of acoustic emission and strain gage monitoring tests conducted by research engineers of Infrastructure Technology Institute from Northwestern University on April 18, 1997 in Sacramento, California.
This report includes the findings of acoustic emission (AE) tests on the Fremont tied arch bridge in Portland Oregon conducted by research engineers from the Infrastructure Technology Institute of Northwestern University on March 24th, 1997.
This paper describes application of AE monitoring techniques to localize the sources of large noises in civil structures. These noises occur during operation of moveable portions of a structure in such things as lift bridges and moveable sports stadium roofs. The use of straightforward AE monitoring techniques can provide clear...