A steel circular hollow cylinder is supported on a circular steel plate.This arrangement is supported on a concrete pedestal. The column has outside diameter d = 250 mm and supports a axial load P = 750 kN.
(a) If the allowable stress in the cylinder is 55 MPa, what is the maximum internal diameter (nearest integer, such as 10, 11, 12, ...., in units of millimetres) of the cylinder?
(b) If the bearing stress on the concrete pedestal must not exceed 11.5 MPa, what is the minimum required diameter D of the base plate? You can assume the cylinder is loaded up to Pallow (not 750 kN) with the internal diameter calculated in part (a).
Hint: The new allowable load Pallow will be slightly larger than 750 kN.