PREVENTION OF ROUND TIMBER LATERAL CRACKING IN WOODEN HOUSE CONSTRUCTION

Vladimir Glukhikh, Anait Akopian

Abstract


The article is devoted to the most widespread defect of regularized round timbers in wooden house construction, i.e. their lateral cracking in the process of further use of buildings and structures. A method is proposed to cut lateral saw kerfs in the round timber surface upon timber rounding, which almost completely excludes appearance of cracks on exposed surfaces. Saw kerfs are cut in the exterior surfaces of round timber on the opposite side of the simultaneously manufactured technological notch.
According to the results of theoretical and experimental studies, it was ascertained that the saw kerf is the main factor which excludes appearance of lateral cracking in regularized round timber. Taking into account the technological notch, the optimal depth of a saw kerf should not be more than 35% of the round timber cross-section radius.
The absence of visible lateral macro-cracks on exposed surfaces of round timber will improve the appearance of a building and prolong its service life. Macro-cracks appear at the bottom of the technological notch and at the bottom of the saw kerf which serve as stress concentrators. Such stresses occurring due to the hygroscopic moisture gradient along the round timber cross-section radius and anisotropy of wood shrinkage in points with stress concentrators can exceed the limit values upon extension in the tangential direction, wherefore macro-cracks will form in the areas with stress concentrators.
According to estimates, additional energy consumption for making a lateral saw kerf will be 1–2%.

Keywords


Wooden house construction, technological notch, crack formation, round timber cracking

Full Text:

PDF

References


Chernykh, A. G. (2008). Dereviannoe domostroenie [Wooden house construction]. Saint Petersburg: Saint Petersburg State University of Forestry, p. 343. (in Russian)

Glukhikh, V. N. (2007). Anizotropiia drevesiny kak faktor dlia povysheniia kachestva sushki pilomaterialov [Wood anisotropy as a factor to increase the quality of timber drying-out]. Saint Petersburg: Saint Petersburg State University, p. 160. (in Russian)

Glukhikh, V. N., Akopian, A. L. (2010a). K voprosu ob umen'shenii vnutrennikh napriazhenii usushki v kruglykh lesomaterialakh naneseniem prodol'nykh propilov [On decrease in internal shrinkage stresses in round timber by cutting lateral saw kerfs]. In: Proceedings of the International Scientific and Practical Conference of Young Scientists and Specialists " Modern problems and prospects of sustainable forestry in market conditions". Saint Petersburg: Saint Petersburg State University of Forestry.

Glukhikh, V. N., Akopian, A. L. (2010b). Napriazheniia usushki v kruglykh lesomaterialakh s prodol'nym propilom [Shrinkage stresses in round timber with lateral saw kerfs]. Bulletin of the Saint Petersburg Academy of Forestry, 193, pp. 288–233.

Jlinen, A. (1952). Über die mechanische Schaftformtheorie der Bäume [On the theory of the shape of the tree trunk]. Higher technical school in Finland, vol. 6, p. 51. (in German)

Kuznetsov, A. I. (1950). Vnutrennie napriazheniia v drevesine [Inner stresses in wood]. Мoscow: Goslesbumizdat, p. 60. (in Russian)

Lekhnitskiy, S. G. (1956). Anizotropnye plastinki [Anisotropic plates]. Мoscow: Fizmatgiz, p. 463. (in Russian)

Sergeyevichev, A. V. (2010). Deformativnost' drevesiny i napriazheniia pri sushke [Increase in the effectiveness of timber rounding through the improvement of the cutting mechanism]. PhD thesis in Engineering. Saint Petersburg: Saint Petersburg State University of Forestry, p. 160. (in Russian)

Shevchenko, V. A., Feller, M. N. (1964). Raschet formoizmeniaemosti drevesiny [Calculation of wood dimensional instability]. Kiev. (in Russian)

Shevchenko, V. A., Feller, M. N. (1962). Rivnjannja vnutryshnyh napruzhen' u derevyny pry ii vysyhanni [Equalizing internal stresses upon wood drying-out]. Bulletin of the Academy of Civil Engineering and Architecture of the UkrSSR, 3. (in Ukrainian)

Ugolev, B. N. (1971). Deformativnost' drevesiny i napriazheniia pri sushke [Strain capacity of wood and stresses upon drying-out]. Мoscow: Lesnaya Promyshlennost (Forest Industry), p. 174. (in Russian)

Ugolev, B. N. (1986). Drevesinovedenie s osnovami lesnogo tovarovedeniia [Wood science with the basics of forest merchandizing technique]. Мoscow: Lesnaya Promyshlennost (Forest Industry), p. 367. (in Russian)




DOI: https://doi.org/10.23968/2500-0055-2017-2-3-3-10

Refbacks

  • There are currently no refbacks.




     
ISSN: 2500-0055