Calculating Timber Panel Walls | 4. Wall Design
Technical Article
This article describes the design of timber panel walls due to generated horizontal loads.
The wall design refers to the third article of this series.
System
The wall 4 at the bottom right will be designed in this article. The position of the wall is indicated in Figure 01. You can download the corresponding model with the forces at the end of this article.
The system values are already included in Part 2 , the most relevant ones are listed below.
- Material beam= C24
- Cross-section of beam = 6/12 cm
- Material of sheeting = OSB 3
t = 18 mm one-sided
ρ_{m, O} = 439 kg/m³
G = 108 kN/cm² - k_{ser} = 159 N/mm
- b_{E} = b + t = 12 cm + 1.8 cm = 13.8 cm
- Staples d = 1.5 mm, t = 45 mm
- Distance staples a_{v} = 60 mm (single row)
- Grid = 62.5 cm
- Tie rod with 10 nails
Diameter = 4.2 mm
fully nailed - Wall length = 1 m (no intermediate rib)
- Wall height = 2.75 m
- Force = 5.67 kN
The calculation is performed at the characteristic level without partial safety factors. The design is performed according to clause 9.2.4.2 of Eurocode 5. Design requirements such as the minimum thickness of sheeting, etc. are met.
Ultimate limit state staples:
${\mathrm{M}}_{\mathrm{y},\mathrm{Rk}}=150\xb7{\mathrm{d}}^{3}=150\xb71,{5}^{3}=506\mathrm{Nmm}$
${\mathrm{f}}_{\mathrm{h},1,\mathrm{k}}=65\xb7{\mathrm{d}}^{-0,7}\xb7{\mathrm{t}}^{0,1}=65\xb71,{5}^{-0,7}\xb7{18}^{0,1}=65,3\mathrm{N}/{\mathrm{mm}}^{2}$
${\mathrm{F}}_{\mathrm{f},\mathrm{Rk}}=1,1\xb7\sqrt{2\xb7{\mathrm{M}}_{\mathrm{y},\mathrm{Rk}}\xb7{\mathrm{f}}_{\mathrm{h},1,\mathrm{k}}\xb7\mathrm{d}}=1,1\xb7\sqrt{2\xb7506\xb756,3\xb71,5}=0,33\mathrm{kN}$
Ultimate limit state of timber frame wall:
${\mathrm{F}}_{\mathrm{v},\mathrm{Rk}}=\frac{{\mathrm{F}}_{\mathrm{f},\mathrm{Rk}}\xb7{\mathrm{b}}_{1}\xb7{\mathrm{c}}_{1}}{{\mathrm{a}}_{\mathrm{v}}}=\frac{0,33\mathrm{kN}\xb7100\mathrm{cm}\xb71}{6\mathrm{cm}}=5,5\mathrm{kN}$
$\frac{5,67\mathrm{kN}}{5,5\mathrm{kN}}=1,031$
The ultimate limit state of the timber frame wall is exceeded. For the ultimate limit state, it would be sufficient to reduce the distance of the staples by half a centimeter to 5.5 cm. However, the slip mentioned in the previous articles would also have to be recalculated in this case.
Ultimate limit state anchorage:
External forces to be introduced
${\mathrm{F}}_{\mathrm{max}}=\frac{\mathrm{F}\xb7\mathrm{h}}{\mathrm{b}}=\frac{5,67\mathrm{kN}\xb7275\mathrm{cm}}{100\mathrm{cm}}=15,6\mathrm{kN}$
Fully nailed with 12 ribbed nails, the ultimate limit state is 20.5 kN > 15.6 kN according to the manufacturer's table values.
The design is thus fulfilled.
Timber design:
Buckling design in wall plane not necessary because timber is held by paneling.
For design with RF-TIMBER Pro, see Model 3 and Figure 03.
Compression perpendicular to the grain
${\mathrm{f}}_{\mathrm{c},90,\mathrm{k}}=0,2\mathrm{kN}/\mathrm{cm}\xb2$
${\mathrm{\sigma}}_{\mathrm{c},90,\mathrm{k}}=\frac{{\mathrm{F}}_{\mathrm{c},90,\mathrm{k}}}{{\mathrm{A}}_{\mathrm{ef}}}=\frac{15,6\mathrm{kN}}{12\mathrm{cm}\xb7(6\mathrm{cm}3\mathrm{cm})}=0,14\mathrm{kN}/{\mathrm{cm}}^{2}$
$\frac{{\mathrm{\sigma}}_{\mathrm{c},90,\mathrm{k}}}{{\mathrm{k}}_{\mathrm{c},90}\xb7{\mathrm{f}}_{\mathrm{c},90,\mathrm{k}}}=\frac{0,144}{1,25\xb70,2}=0,5761$
Buckling analysis
$\frac{{\mathrm{b}}_{\mathrm{net}}}{\mathrm{t}}=\frac{100\mathrm{cm}-6\mathrm{cm}}{1,8\mathrm{cm}}=52,2100$
Summary
In this last article of this series, the design of the timber panels is shown. You can calculate the stiffening of the building very well with the program using the analysis per story. Together with simple manual formulas, the design of wood-based panels is quick and easy.
Keywords
Timber panel Compression perpendicular to the grain Stand Buckling resistance OSB
Downloads
- Model 1 of Technical Article | RFEM 5 File
- Model 2 of Technical Article | RFEM 5 File
- Model 3 of the Technical Article | RFEM 5 File
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Frequently Asked Questions (FAQ)
- How can I get the member end forces to design the connections?
- I design timber components. The deformations of load combinations deviate from the manual calculation exactly by the factor of the material partial safety factor. Why?
- How can I run the RX‑TIMBER Frame plugin? I did not find it in the Add-on Modules menu nor in Project Navigator - Data.
- I have a question about the results of the serviceability limit state design: How is the increment of the dead load by the factor 1.8 and the imposed load by 1.48 explained in the result combinations for the SLS design?
- Where can I adjust the effective length l_{ef }according to Table 6.1 of Eurocode 5 in the TIMBER Pro add-on module?
- Is it possible to display more values for the stress distribution over the layers in RF‑LAMINATE?
- How can I design dowel-laminated timber (DLT) or nail-laminated timber (NLT) in RFEM?
- I would expect the results from my load combination (CO) set to a linear analysis to equal the summation of the results from my load cases (LC) also set to a linear analysis. Why do the results not match?
- Which Dlubal Software programs can I use to calculate and design timber structures?
- How can I set the deformation coefficient k_{def} in the program?