The influence of freezing on the nail withdrawal capacity of Norway Spruce and European Larch wood

Abstract

Environmental conditions and temperature oscillations can influence wood properties. Accordingly, the performance of wood connections such as nails could be affected by freezing and heating temperature. Thus, in the present work, the impact of freezing/heating temperatures on the nail withdrawal power of Norway Spruce (Picea abies (L.) H. Karst.) and European Larch (Larix decidua Mill.) has been studied. Three types of the wood nail; smooth, helically threaded, and annularly threaded were studied, and two different freezing heating steps have been implemented (-15°C/70°C and − 25°C/70°C). Withdrawal capacity was distinguished on two various anatomical directions; radial and tangential surfaces. The freezing could cause a considerable destructive impact on the nail withdrawal capacity of both wood species. The highest drop has found for smooth nail (A) for larch wood in the tangential direction with 73% and 69% decrease and radial direction, with 70% and 63%, at temperatures − 15°C/70°C and − 25°C/70°C, respectively. Furthermore, spruce wood exhibited a meaningful reduction for both tangential (69% and 63%) and radial (54% and 56%) directions and smooth nail (A), at temperatures − 15°C/70°C and − 25°C/70°C, respectively. The highest reduction was found for annularly threaded nails (C).