Answer:
The reduction of the shear stiffness is caused by the fact that the fibers perpendicular to each other have a very small stiffness and a low strength. For this reason, the rolling shear strength of CLT panels is also very small.
For cross-laminated timber plates, glued sideboards are assumed on boards. The boards are applied in the longitudinal direction along the x‑axis of the coordinate system (Image 02). Bei den Schubspannungen im Bild 2 wird die Schubspannung τyz somit der Rollschubfestigkeit gegenüber gestellt.
The same applies to the shear stiffnesses. In the direction of the minor axis (yz-plane), the stiffness of the individual boards is considerably smaller than in the direction of the principal axis (xz‑plane) and larger than in the xy‑plane. The coordinate system shown in Image 02 should be placed on the boards in Image 03.
