A structure is being designed to support a large hopper over a plastic extruding machine,...

A structure is being designed to support a large hopper over a plastic extruding machine, as sketched. The hopper is to be carried by four columns which share the load equally. The structure is cross-braced by rods. It is proposed that the columns be made from standard 2-in schedule 40 pipe. They will be fixed at the floor. Because of the cross-bracing, the top of each column is guided so that it behaves as if it were rounded or pinned. The material for the pipe is AISI 1020 steel, hot rolled. The hopper is designed to hold 20 000 lb of plastic powder. Are the proposed columns adequate for this load?

FIGURE

FIGURE PI  Hopper for Problems.