Portland State University

Friday Transportation Seminars at Portland State University have been a tradition since 2000. We've opened up PSU Transportation Seminars to other days of the week, but the format is the same: Feel free to bring your lunch! If you can't join us in person, you can always watch online via Zoom.

THE TOPIC 

For concrete bridges without existing plans, simplified and highly conservative load rating (structural evaluation) methods may be used, which can lead to unnecessary load restrictions, unjustifiable strengthening, or in the worst case, preventable replacements. Avoiding these outcomes not only saves money but it prevents carbon emissions from longer travel and construction activities and resources associated with replacement.

This presentation discusses a case study of a prestressed concrete bridge that required a load rating, and for which no plans existed. Imaging and image fusion using radar and ultrasonic measurements taken from the top and bottom of the slab were performed to produce a digital cross-section of the bridge. Using this image, the location of the reinforcing steel, as well as the location, size, and content of internal air voids could be determined. After extracting these variables and using them in an improved load rating, load restrictions were found to not be necessary...