... 1 .22 = 715 1cm 12 12 12 12 3 h t 2. t f b f 2.1 .22 23 .0,8 Iy = + w w = + = 17 76cm 12 12 12 12 + Bún knh quỏn tớnh: I 715 1 ix = x = = 10 ,7cm A 62, 4 Iy 17 76 = 5,33cm A 62, 4 2. I 2. 715 1 = ... 22 .13 34 t w h w Ix = + + t f b f = + 2. + 1 .22 = 15 115 cm 12 12 12 12 3 3 h t 2. t f b f 2.1 .22 33.0,8 Iy = + w w = + = 17 76cm 12 12 12 12 + Bún knh quỏn tớnh: ix = Ix 15 115 ... h d 1 025 . 42 Q.Sc = Ibt w Vi : Sc = 20 ,5 .1. 18 = 369cm t w h 1 ,2. 40 w Ib = = = 6400cm 12 12 = 25 538 ,18 .369 = 12 2 7,1kG / cm 6400 .1 ,2 td = 830 ,2 + 3. 12 2 7, 12 = 22 81, 8kG / cm < 1, 15f = 1, 15 . 21 50...