Civil Engineering/Question from the TV show CSI
Hello. My name is Jon and I'm a researcher for the American TV show CSI: Crime Scene Investigation. I'm not sure if you've heard of our show but it's my job to make sure our scripts are as accurate as possible, and to achieve this goal I often rely on professionals such as yourself.
The reason I'm contacting you is in the hopes you can help us with a question for our next episode about bridges and steel.
We find steel evidence and want to be able to say it was from a bridge. Could you tell us what properties steel particulates from a bridge could have that could help tell us that those particulates were from metal that was near a body of water?
Would those steel particulates be different than other steel?
Or would the steel in a bridge be treated/mixed with a specific "rust retardant" that could tell us it was bridge steel?
My understanding is that some bridges are painted to help protect them from the high salt content in the air which can cause the steel to corrode or rust. If we found some of that paint from a bridge that served that purpose, what would it look like under the mass spec?
I'm sure a lot of this is guesswork, or perhaps outside your area of expertise. But we truly appreciate any help you can provide.
I list some probable causes :
1- Local or total corrosion of steel due to environmental effects.
2- Laminarity of steel due to defects in steel: In this situation steel is prone to fail under loading along specific layers.
3- Exploding of bolts caps due to fatigue effects.
4- Low quality of steel due to high carbon content( old bridges) will result to porosity and corrosion and brittleness eligibility.
Fatigue is the essential source of bridges loading and failure. The combination of brittleness of steel due to its low quality and fatigue effect may result to brittle failure like what you seem to have observed.
Please don't hesitate to ask me further if needed.