Shear Deflection

For CLT, I-joists, and SCL materials, the analysis includes the effect of shear deflection. The Timoshenko shear deflection factor

is incorporated into the stiffness matrix used to determine rotations at member ends, where

• k is a form factor depending on cross-sectional shape, = 1.2 for SCL and glulam; 1.0 for CLT.
• G is the shear modulus in units of force/area.
• A is the area of the cross sectional section.
• GA is the shear stiffness in force units.
• L is the member length
• EI is the bending stiffness in units of force x area.

In addition to the effect on rotations, fixed-end deflections using shear stiffness GA and form factor k are calculated and added to those from the bending deflection formulae, which use the bending stiffness EI.