Question

143 t 13 tHo W 16 x E at lo A building frame is shown. Using the alignment charts determine the effective column length factor (K) and the slenderness ratio KL/r for each column. Note, the columns on the upper level are subject to sidesway and beams bend about their strong axis.

Answer 1

COLUMN-AD MOMENTS OF INERTIA Columns w12x40 307 in ry = 1.94 in Beams/ Girders W16x40 518 in W16x40 16 W12x40 307 16 x 12 20 518 20 x 12 0.74 From alignement chart, for sway not prevented K0.76 for braced frame] KL/ry= 0.76 x 75.2 12 / 1.94 16 x

COLUMN-BE MOMENTS OF INERTIA Columns W12X26204 in W12X40 307 in ry 1.94 Beams/ Girders W16X40 = 518 in4 W14X48 - 484 in W12X26 13 W16X40 14X48 16 W12X40 204 13 x 12 +307 16 x12 20 18 518 20 x 12 484 -18 x 12 - 0.66 10 From alignement chart, for sway not prevented, 0.86 for braced frame] KL/ry 0.86x1612/ 1.94 85.11

COLUMN-EG MOMENTS OF INERTIA Columns W12X26204 in ry w12x40 = 307 in' 1.51 in W14X48 Beams/ Girders W12X26 W14X48484 in W16x40 518 in W14X48484 in 13 14X48 W16X40 W12X40 16 204 13 x 12 18 20 0 484 20 x 12 18 x 12 0.58 204 13 x 12 307 16 x12 518 484 20 x 12 18 x12 -0.66 From alignement chart, for sway not prevented Kx1.2 for unbraced frame] 1.51 KL/ry1.13x 12/ - 123.97

COLUMN-CF MOMENTS OF INERTIA Columns 204 in 307 in 1.94 in4 W12X26- W12X40 ry Beams/ Girders 484 in W14X48 12X26 13 W14X48 16 W12X40 204 307 13 x 12 16 x 12 18 484 18 x 12 1.30 10 From alignement chart, for sway not prevented Kx 0.85 for braced frame] KL/ry = 12/ 0.85 x 84.12 16 x 1.94

OLUMN-F MOMENTS OF INERTIA Columns 204 in 1.51 in 307 in W12x26- ry W12x40 W14x48 Beams/ Girders 484 in W14x48 W12x26 13 W14x48 484 in 16 W12x40 204 13 x 12 18 484 18 x 12 0.58 204 + 307 13 x12 16 x 12 484 18 x 12 1.30 From alignement chart, for sway not prevented 1.3 [for unbraced frame] 13 x 12/ 1.51 1.3 x - 134.30