Internal Forces

by Tiffany Patterson

Submitted : Spring 2012

To find the shear and bending moments on a beam, all forces acting on the beam must be accounted for. The support reactions at each support were calculated by summing forces in the x- and y-directions, as well as summing moments about a point. These forces directly affect the shear force diagram, causing sudden discontinuities when they are applied. To determine the effect a distributed load has on the shear force diagram, the negative integral of the load at a point of interest is taken. For the moment diagram, the integral of the shear force diagrams is taken, and the couple moment on the beam is added where applied. In order to find where there was zero shear force and zero moment on the diagrams, the x-values were calculated using the integrals equations. It was determined that there were two points of zero shear force on the beam, at 3.33 ft. and 6.94 ft. from the left end. There was one point of zero moment on the beam at 9.51 ft. Both the shear force and bending moment diagrams can be seen in the appendix.

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