The horizontal beam ABC shown in the figure is supported by columns BD and CE. The beam is prevented from moving horizontally by the pin support at end A. Each column is pinned at its upper end to the beam, but at the lower ends, support D is a guided support and support E is pinned. Both columns are solid steel bars (E = 30 ×106 psi) of square cross section with width equal to 0.625 in. A load Q acts at distance a from column BD.
(a) If the distance a = 12 in., what is the critical value Qcr of the load?
(b) If the distance a can be varied between 0 and 40 in., what is the maximum possible value of Qcr What is the corresponding value of the distance a?
