I have a problem to do with my project in college. I'm creating a hanging fire pit, basically made of 3 lengths of square steel bar connected to a plate at the top and on hinges. The 3 legs of the frame move in slots and when in the open position would be at 45 degrees. The actual fire pit is hanging from the plate via a chain. My problem is that my tutor argues the weight of the chain/fire pit would cause the square tubes to bend when in the open position, but me and another tutor argue it would not- and none of know how to go about calculating it. So does anybody know the maximum weight 3 20x20mm square steel tubes when arranged at 45 degrees like I described would be able to take before deforming?