The shear stress at the face of the first interior support, fvi, is determined as follows:

Where:

V1 = The shear force at the first interior support, lb

= 1.l5wL/2= 1.15(934)(12)/2 = 6445 lb

The shear stress at the face of the exterior support, fv2,is determined as follows:

Where:

V2 = The shear force at the exterior support, lb

= wL/2 = (934)(12)/2 = 5604 lbs

So; fv = fv1 = 41.02 lb/in2

Fv= 1.0%f*m = %1350 lb/in2 = 36.7 lb/in2

fv =41.02 psi > Fv = 36.7 psi; Therefore, shear reinforcement is required in the beam at the interior support.

Since fv > 20 psi and there is required negative reinforcement, web reinforcement must be provided to carry

the entire shear for a distance of one-sixteenth the clear span beyond the point of inflection. The allowable

shear load based on 20 psi, Vallow, is:

Vallow = (20)(7.62)(20.62) = 3142 lb

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