17.2 : מתח גזירה

A structure when subjected to transverse forces develops internal forces in the sectional plane between the points where the forces are applied.

The magnitude of these resultant forces is defined as the shear and the stress developed is called shearing stress.

Consider two plates connected by a bolt. When tension forces are applied to the plates, stresses will develop in the section of the bolt corresponding to the plane between the horizontal surfaces of the plates.

The stresses result in a single shear, equal to the applied tension forces. Shearing stress is not uniformly distributed and varies from zero at the surface of the member to a maximum value exceeding the average value.

The average shearing stress is computed by dividing the shear by the area of the cross-section.

When splice plates are used to connect two plates, shear occurs in each of the two planes of the bolt, which is referred to as double shear. The average shearing stress in each plane is determined by dividing the applied force by twice the cross-sectional area.