Why do the beams of tower cranes use a triangular cross section?
Think about the ways that heat could be transferred into the box from the outsideFirst, there would be conductionNewspaper doesn't conduct heat very well, and air conducts it even lessSurround your box with loosely crumpled newspaperHeat could also be transferred by radiationTo prevent this, you can surround the newspaper with foil to reflect heat away before it hits the newspaper.
Since the triangle is one of the the most stable structural shapes it makes it a good design for the boomNot only do tower cranes deal with lifting loads but they also have to swing them from side to side as they position them for placementA box shape would not be as good at resisting the lateral forces when the boom moves from side to side.
