Research Abstracts Online
2008 - March 2009
University of Minnesota Twin Cities
Institute of Technology
Department of Civil Engineering
PI: Catherine E. French
Co-PI: Carol K. Shield
Co-PI: Henryk K. Stolarski
I-35W Health Monitoring
After the collapse of the old I-35W bridge, a new bridge was designed that includes instrumentation to understand the behavior of the new system and to compare it to assumed design models. The instrumentation consists of strain gauges in various cross sections of the bridge. These gauges measure strains, and the associated stresses can be computed for the instrumented cross sections. Additionally, thermistors have been placed to measure the thermal gradient through the depth of the box and through the thickness of the webs, bottom flange, and top flange at one of the sections.
The bridge is being modeled using ABAQUS. The measurements taken from the thermistors can be applied to the model to investigate the effects due to thermal gradients. Load tests were performed upon completion of the bridge construction. These load cases will also be applied to the model. A comparison of the measured data and model output can be used to investigate the validity of the assumptions used in design. It is anticipated that the actual behavior of the bridge will be different than that predicted by design (e.g., plane sections assumed to remain plane in design, may not be the case in the field). As a consequence, the model can be used to better interpret the implications of the measured data.
Brock Hedegaard, Graduate Student
Ben Jilk, Graduate Student