Roof Water dwg file. 1._ Structural concrete f'c = 250 kg / cm2. 2._ Reinforcement steel blast furnace high strength  Fy = 4200kg / cm2. 3._ Coatings:               In foundation .............................. r = 5.0 cm.        In columns .................................. r = 2.0 cm.        4. The dice stirrups must comply with                                  = Stirrup diameter