6973 KB0 KB199820242021Fajdiga, GorazdHumar, MihaLipovec Zupanc, Enejštevilka:2letnik:70str. 31-40ISSN:0024-1067DOI:10.26614/les-wood.2021.v70n02a01COBISSID_HOST:78746371URN:URN:NBN:SI:doc-PYZ6L1ENenBiotehniška fakulteta, Oddelek za lesarstvoLes (Ljubljana)European larchfatiguelesmacesenold woodRuardova graščinaRuard's Mansionstar lesutrujanjewoodComparison of mechanical properties of recent and 400-year-old European larch wood| Primerjava mehanskih lastnosti recentnega in 400 let starega lesa evropskega macesna|Wood has been the leading building material throughout the history of mankind. Wood has several advantages over other construction materials, which also makes it one of the most promising materials of the future. The environmental aspect also plays a major role today, as wood is a natural, renewable resource whose processing is very energy-intensive. Due to its repeated and widespread use in construction, the prediction of mechanical properties and their change over time is also very well known, as the overall safety of all buildings also depends on it. Therefore, we compared the mechanical properties of fresh European larch (Larix decidua) and 400-year-old larch found in the Ruard manor house on the Stara Sava in Jesenice, where the renovation of the Upper Sava Museum is currently underway. In order to predict what will happen to the fresh wood over the long term, it is necessary to expose the wood to the same conditions, i.e. to change it with dynamic loads or material fatigue. The effect of aging on flexural strength has not been confirmed. Fatigue results show that old wood withstood about 18 times fewer load cycles than recent larch woodLes velja za vodilni gradbeni material v zgodovini človeštva. Pred drugimi inženirskimi materiali ima veliko prednosti, kar ga uvršča med vodilne materiale prihodnosti. Zelo pomembno je dejstvo, da les kot naraven material uvrščamo v skupino materialov, ki imajo majhen negativen vpliv na okolje. Poleg tega je njegova predelava energijsko nezahtevna. Zaradi ponovne široke uporabe v gradbeništvu je pomembno dobro poznati in tudi napovedati mehanske lastnosti ter ovrednotiti posledice delovanja biotskih in abiotskih dejavnikov na mehanske lastnosti skozi daljše časovno obdobje. Od tega je odvisna tudi varnost starejših zgradb. Tako smo ob priložnosti primerjali mehanske lastnosti svežega evropskega macesna (Larix decidua) in okoli 400 let starega macesna, odvzetega iz Ruardove graščine na Stari Savi na Jesenicah. V okviru tega prispevka smo ovrednotili statično upogibno trdnost in vpliv cikličnih obremenitev na obnašanje stare in sveže posekane macesnovine. Vpliva staranja na upogibno trdnost nismo potrdili. Rezultati utrujanja lesa kažejo, da je star les prenesel približno 18-krat manj obremenitvenih ciklov kot recentni les macesnaTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaZveza lesarjev Slovenije