Projects / Programmes source: ARIS

Razvrščanje lesenih konstrukcijskih elementov po trdnosti (Slovene)

Research activity

Code Science Field Subfield
2.01.03  Engineering sciences and technologies  Civil engineering  Constructions in civil engineering 

Code Science Field
2.01  Engineering and Technology  Civil engineering 
Evaluation (rules)
source: COBISS
Researchers (8)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  01392  PhD Bojan Bučar  Forestry, wood and paper technology  Researcher  2009 - 2012  174 
2.  10340  PhD Dominika Gornik Bučar  Forestry, wood and paper technology  Researcher  2009 - 2012  239 
3.  25423  PhD Tomaž Hozjan  Civil engineering  Researcher  2009 - 2012  302 
4.  29320  PhD Aleš Kroflič  Civil engineering  Junior researcher  2009 - 2012  30 
5.  24096  PhD Tomaž Pazlar  Civil engineering  Researcher  2009 - 2012  120 
6.  04054  MSc Jelena Srpčič  Civil engineering  Researcher  2009 - 2012  367 
7.  13057  MSc Bogdan Šega  Forestry, wood and paper technology  Researcher  2009 - 2012  205 
8.  08437  PhD Goran Turk  Civil engineering  Head  2009 - 2012  524 
Organisations (3)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0481  University of Ljubljana, Biotechnical Faculty  Ljubljana  1626914  66,743 
2.  0792  University of Ljubljana, Faculty of Civil and Geodetic Engineering  Ljubljana  1626981  25,753 
3.  1502  Slovenian National Building and Civil Engineering Institute  Ljubljana  5866324000  10,477 
Significance for science
In order to estimate material properties a number of experiments have to be performed. Since the timber is a natural material with high variability and relatively low correlation between non-destructive properties and strength a large number of tests need to be done. If the sample is not large enough the results may be misleading. Very careful selection of representative sample and accurate measurements are the basis for this important database on spruce timber properties in Slovenia. This data base has been and will be an important source for different research purposes. There are two main methods for the machine setting determination which are both described in standard: machine controlled and output controlled. Practical experiences show that both methods are to complicated and may lead to settings which don’t fulfill the requirements of strength grades. The settings may be too conservative and thus not economical for higher quality timber and non-conservative and thus potentially dangerous for lower quality timber. A considerable effort has been invested in the development of new methods. The prediction limit method proposed by colleagues in Sweden was used for the initial setting determination. The second part is an adaptive feature of the machine settings determination which changes the settings continuously according to the timber which is currently graded. The first results are promising since adaptive settings give both more reliable and safer settings. One very important advantage of the proposed method is its robustness.
Significance for the country
It is well known that Slovenia doesn’t obtain the full value of its timber. All too often the logs are exported into foreign countries where the timber is sawn and graded only to be sold back to Slovenian customers for a considerably higher price. One of the reasons for this situation was certainly the fact that it was not allowed to grade and mark Slovenian timber. The project removed some of the main obstacles; the transformation table between visual and strength grades is now published in standards for Slovenian spruce. There are now some grading machines with settings valid for Slovenia. The results of the project indicate the high quality of Slovenian timber. The optimal grading of the sample shows that more than 40 % of the specimens are in strength class C40, more than 60 % in class C35 and about 90 % in class C30. These values are valid for the cases where the stated class was the highest in which the grading was done. Since most of Slovenian timber is used as C30 timber, we can conclude, that grading in higher grades could significantly effect the competitiveness of structural timber.
Most important scientific results Annual report 2009, 2010, 2011, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2009, 2010, 2011, final report, complete report on dLib.si
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