The reported slip in the member is a computed value and slightly different than the value observed in the double shear test. In a double shear test, the force being applied as a pure shear force. Because of this, the slip is often visualized as the pure axial slip shown in Figure 1.
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In real world practice, the end rotation and axial deformation both cause the spring to lengthen. Because of this, the effective slip is computed using the force in this spring. The effective slip is computed as the total force in the spring divided by the spring stiffness. This effective slip is than compared against the given slip limits to determine if the connectors are yielding.
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