Maximum cantilever for CLT roof

[efFeb]

Hi! I am designing a roof with a significant CLT cantilever on one end. The deflection equations in the code are set up for a simple span beam. Does anyone have any guidance on maximum cantilever for a CLT panel, or for an approach to calculating the cantilever deflections (id expect that shear deformation would be much higher than for the simple span)

Thanks so much!

 

[canwesteng]

Is the cantilever causing in plane or out of plane bending? And which code excatly? IBC does allow you to consider two times the simple span deflection for cantilevers

 

[BAretired]

Shear deformation is normally ignored. Take the normal cantilever deflection plus theta*Lc where theta is the backspan rotation due to the cantilever moment and Lc is the length of cantilever.


Google "Beam Diagrams and Formulas" and you will find several load combinations. The sketch above is for uniform load over the backspan and the cantilever.

 

[T9809]

Hi,

This is a high level design guide from NZ/Australia with a spanning table:

https://xlam.co/wp-content/uploads/2024/10/003-XLAM-Structural-Design-Guide-Australia-NewZealand-June-2020.pdf

When calculating the deflection of these timber members its very important to account for the long term creep and the additional shear deformations due to rolling shear.