4. Design for Combined Loads (8 points): Citizens of the great city of Philadelphia have a time-honored tradition of climbing things to celebrate, or grieve, the outcomes of sporting events. Assume that the streetlight shown below is manufactured from A36 steel with a yield strength of 36000 psi and has a hollow circular cross-section (e.g., a "pipe") with a maximum wall thickness of 0.5 inches. What should outer diameter of the base of the streetlight be to support 10000 lbf of Philly fans with a FOS of 2.0? Specifically, you should re-design the outer diameter three times: (1) once for axial stress only, (2) once for bending stress only, and (3) a third time for the combination of axial+bending. What do you results tell you about the primary type of loading in the structure? 5ft 20ft