’ Name at least 5 reasons why manhole covers are round.’
1. Can’t fall thru its circular opening.
2. Rotational position doesn’t matter when installing.
3. Can be rolled to transport.
4. Ease of manufacturing, perfect circle after being on a lathe.
5. Greater dispertion of force loading on the edges.
6. Round manholes are the strongest and most material-efficient shape against the compression of the earth around them.
7. A round cover is cheapest to make because it requires the least amount
of metal to produce the largest area (opening).
I’ll stop explaining why but there are more reasons.
Manhole covers are cast, not machined.
Hadn’t thought of weight distribution or least amount of material.
Nice going ...
This is my favorite of all the interview questions I’ve been asked, as it caused me to sit back and think.