My PH.D. research topic is focused on analyzing the use of carbon fiber reinforced polymers (CFRP) to strengthen our aging steel infrastructure. Specifically we are looking at bond strength between CFRP and highly corroded steel bridge girders. The CFRPs we are looking at is about 4 times stronger than steel and easier to apply in the field that conventional methods (welding). Another advantage to CFRP is that it is non corrosive, meaning that it will not deteriorate over time. The end goal of the first phase of this project is to provide a cheap but sufficiently strong retrofit solution to bridges to achieve their previous or even greater load capacity . In doing so we are looking at bond characteristics (small scale level) and different retrofit solutions on retired steel bridge girders (large scale level). Biased on our results we will determine what CFRP and detail is ideal to increase load capacity.
The second phase of my project will be focused on how different levels of corrosion and insitu conditions will effect our bond strength. In doing so we look at how 4 levels of corrosion (none to extreme) will effect our bond strength. Theses 4 levels of corrosion specimens will be exposed to 4 different environmental conditions (control, rural, marine, and urban) across the sate of Virginia. Conditions at these sites vary and some variables we are looking at are: moisture, chloride intrusion, and thermal effects. To get an understanding of how these variables effect our specimens over time they will be tested periodically over 5 years.
The final goals of this research is to be able to tell DOT’s the following:
- What environments CFRP retrofits can be appropriately used in
- Give an idea of the service life of the retrofit solution
- Recommend best practices biased on our retrofit techniques & experiences
- Develop bond characteristics models for different levels of corroded steel to CFRPs
- Come up with a correlation between accelerated laboratory environmental exposure and insitu environmental exposure biased on test data