Question:
Is it possible to perform fire resistance design of cross-laminated timber panels in RF‑LAMINATE?
Answer:
Fire resistance design is not implemented in the RF‑LAMINATE add-on module by default.
However, you can calculate the charring rates yourself and consider them accordingly in the module. In the following example, this is explained on a simple plate.
Structural system (Image 01):
Span 5 m
Plate width 2 m
LC1 (permanent) 1 kN/m² plus dead load
LC2 (medium) 2.5 kN/m²
3 layers
S1 35 mm C24
S2 20 mm C24
S3 35 mm C24
The information regarding the correction factors and stiffnesses can be found in the attached file.
Factors for fire resistance:
Charring rate ß0 = 0.65 mm/min
Pyrolysis zone k0d0 = 7 mm
Charring time t = 30 min
Effective thickness def=t ß0+k0d0=30 min × 0.65 mm/min+7 mm = 26.5 mm
Remaining thickness of Layer 3 = 35 − 26.5 = 8.5 mm > 3 mm → thickness may be applied. (Image 02)
Because of the modified layer thicknesses, a new stiffness matrix results, which is applied in RFEM for accidental combinations with the characteristic stiffness values. For the ultimate limit state, the design values are calculated here (Image 03).