CIB-W18 Timber Structures – A review of meeting 1-43 2 MATERIAL ...
CIB-W18 Timber Structures – A review of meeting 1-43 2 MATERIAL ...
CIB-W18 Timber Structures – A review of meeting 1-43 2 MATERIAL ...
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23-6-1 U Korin<br />
<strong>Timber</strong> in compression perpendicular to grain<br />
Summary<br />
The compressive strength <strong>of</strong> timber perpendicular to grain was investigated.<br />
The study reports tests conducted on whitewood specimens 40 mm x<br />
90 mm x 180 mm in size in central loading or end loading for varying<br />
lengths <strong>of</strong> loading sectors l/L. Upgrading experiment <strong>of</strong> bearing capacity<br />
<strong>of</strong> the timber by Nail-plates reinforcement was found to be unsuccessful.<br />
Discussion and Conclusions<br />
1 It is necessary to agree on a clear strength-bearing capacity criterion for<br />
timber in compression perpendicular to gain.<br />
2 Eurocode 5 brings a parameter Kc,90:<br />
�c,90, d � Kc,90 fc,90,<br />
d<br />
Kc,90 depends upon the length <strong>of</strong> the overhangs <strong>of</strong> the loaded member.<br />
The following table presents a comparison between the values <strong>of</strong> Kc,90<br />
calculated for the loading conditions in this investigation and the experimental<br />
results <strong>of</strong> this investigation. The differences between the compared<br />
values are very large and should be further studied.<br />
3 The investigation covered so far only one kind <strong>of</strong> timber and one cross<br />
section (d/b=2). There is a room for a much wider investigation on the<br />
subject.<br />
Table 2 Comparison between Kc,90 and experimental results.<br />
l/L Central Sector loaded End sector loaded<br />
Kc Experimental<br />
results<br />
Kc Experimental<br />
results<br />
1 1 1 1 1<br />
0.875 1 1.063 1 1.063<br />
0.75 1.006 1.188 1 1.156<br />
0.625 1.025 1.375 1 1.281<br />
0.50 1.061 1.625 1 1.<strong>43</strong>8<br />
0.375 1.124 1.969 1 1.625<br />
0.25 1.237 2.344 1 1.875<br />
0.125 1.478 2.781 1 2.156<br />
27-6-1 C Lum, E Karacabeyli<br />
Development <strong>of</strong> the "critical bearing" design clause in CSA-086.1<br />
Abstract<br />
There are currently inconsistencies in the compression perpendicular-tograin<br />
(C-perp) design procedures in the Canadian code for Engineering<br />
Design In Wood, CSA-086.1-M89. For example, a single specified design<br />
value is given for a species group irrespective <strong>of</strong> the loading condition, or<br />
the lumber grade. On the other hand, different values are assigned to<br />
Douglas-fir lumber and Douglas-fir glulam (glued-laminated timber). These<br />
inconsistencies not only make the design code confusing to designers,<br />
but they also hinder the introduction <strong>of</strong> appropriate C-perp strength values<br />
for products such as machine stress rated lumber. A research program focused<br />
on resolving these inconsistencies in the C-perp design procedures<br />
<strong>CIB</strong>-<strong>W18</strong> <strong>Timber</strong> <strong>Structures</strong> <strong>–</strong> A <strong>review</strong> <strong>of</strong> <strong>meeting</strong> 1-<strong>43</strong> 2 <strong>MATERIAL</strong> PROPERTIES page 2.10