What I want to learn is, for similar cross section properties (area, strength, etc), and length, which one would be easier and more efficient to produce (thus less co2 produced during production) : An I beam or a hollow section beam ?
Should I conclude that there is not a significant difference in terms of CO2 production between types of cross sections ? Is it almost the same work to produce any type of cross section?
blacksmith37, I didn't really get your point.. Why should I get calculated the correlation between atmosphereic CO2 and the global warming curve ?