Question

Learning Goal: To calculate the shear stress at the web/flange joint in a beam and use that stress to calculate the required nail spacing to make a built- up beam. A built up beam can be constructed by fastening flat plates together. When an l-beam is subjected to a shear load, internal shear stress is developed at every cross section, with longitudinal shear stress balancing transverse shear stress. If the beam is built up using plates, the fasteners used must be able to resist the shear at the joints. The loading resisted by the fasteners can be described in the force per unit length of the beam and is called the shear flow. The shear flow at some distance y from the neutral axis can be VQ calculated using the shear formula q= where V is the shear I force, Q is the moment about the centroidal axis of the cross- sectional area above y, and I is the moment of inertia of the cross section. Figure 1 of 1 W IY L

Answer 1

FBD 611 Soulbift mm 181 Heritage A B. 1 By 18 AY equilibdium equation EMAFO 800 X18 x 9 – By *18=0 By = 7200 lb 7200 {Fy=0 800 X18 = Ay Ay = 7200ub force V= 720006 À Maximum Shear q= QV I (6-3)X.182 I 6 X 203 NA 12 I 2542 iny a= moment of area about fly Q = 6X1X (9+015) = 57 in3 Joiut q = 57 X 7200 2542 qs. Non q= = 161.44 ilb lin 161144 53. 81 PS<<900 PS Tman who OK 3 Hence l lin q 161144 s (Spacing )= 240 16144 in S = 14865