Allways interesting to read these topics. People ask questions in a way of which you know they dont know whats important, (So its good that they ask) Then other people think they can give a definitive answer to that question, thereby showing that they have even less insight than the ones who ask.
The engineers who actually know whats involved in structural engineering, rather not get involved in these types of discussions because they know they cant give a conscientous answer without knowing all the variables.
I am not a civil engineer, but the water council approved my building permit calculation over a 40 foot span, because i calculated with the worst case scenario, the retaining wall T elements used have an extremely low ground pressure and are dug below the depth of the canal so washout is impossible. I reverse engineered the retaining walls certified side load into a bending moment, to find what these would support vertically. As deck we used 12 I beams 40 inch high, because we could get them used as a package deal. I ended up with a 120 ton static capacity, and let the authorities decide if this met the civil engineering code, because there is no information online because most people dont build their own bridges...
The bridge should support a 4 inline wheel slurry tank with 20 ton pendle axle load, and a transport tanker with 50 ton combined weight.
