Beam ABCD has a sliding support at A, roller supports at C and D, and a pin connection at B (see figure). Assume that the beam has a rectangular cross section (b = 100 mm, h = 400 mm). Uniform load q...

Beam ABCD has a sliding support at A, roller supports at C and D, and a pin connection at B (see figure). Assume that the beam has a rectangular cross section (b = 100 mm, h = 400 mm). Uniform load q acts on ABC and a concentrated moment is applied at D. Let load variable q = 25 kN/m, and assume that dimension variable L = 1.25 m. First, use statics to confirm the reaction moment at A and the reaction forces at C and D, as given in the figure. Then find the ratio of the magnitudes of the principal stresses (

₁/
₂) just left of support C at a distance d = 250 mm up from the bottom.