The shape of the beam made of U profile ensures safe loading. Find the length c of the overhangs so that it can move. Of the material Safety stress (σç) emn = 50 N / mm2 for tension and compression...

The shape of the beam made of U profile ensures safe loading. Find the length c of the overhangs so that it can move. Of the material Safety stress (σç) emn = 50 N / mm2 for tension and compression conditions, (σb) emn = 80 N / mm2. Support spacing of the beam L = 6 m, cross section its dimensions are a = 210 mm, b = 150 mm and wall thickness t = 40 mm. The loading condition is P = 30 kN and q0 = 40 kN / m.