Slab thickness calculation

The cladding thickness is determined by taking the following type of stresses into account: the flexural stresses on the stone slab and the cutting stress originated in the anchor points.

The flexural stresses on the slab are caused by the wind or seismic actions.
The calculation of the slab thickness due to wind pressure can be determinated by the expression below:

Where: e: slab thickness in mm P: wind pressure in kN/m2 L: slab opening in mm (separation between anchored edges) ViE: lower expected value of flexural strength in MPa Fs = 6 safety factor recommended against flexural strength

The calculation of the slab thickness due to seismic action can be determined by a very similar expression, although, in this case, it is necessary to consider the seismic pressure value instead of the wind pressure (P) calculated according to the current Technical Code of the Building.

The slab must have a resistant section in the fixing point, so the pull out strength of the anchor reaches, at least, the value given by the expression:

Ra: anchor strength value in kN P: wind pressure in kN/m2 L y W: slab length and width in m n: number of anchors in the slab considered F:safety factor against the anchor strength value. It is recommended to be F = 8

Generally, the use of bolt anchors presents two requirements: Ra ≥ 500 N y Ra ≥ 1,2 W (where W is the slab weight).

Diagram of the wind pressure action on a cladding