the effect of altitude on bending creep behavior hornbeam (case study, nowshahr meshelak branch)

This study aimed to investigation the effect of altitude on the bending creep behavior of hornbeam lumber (Carpinus betuluse). For this purpose, 9 hornbeam trees from three different altitudes (400, 800 and 1100m) from forestry projects of Meshelak Nowshahr were selected. 54 Clear samples were cut at mature wood in diameter breast height (DBH). The prepared samples (dimensions: 2.5 × 2.5 × 41cm) in a room at temperature of 20 C and relative humidity (RH) 65 % were conditioned. Afterward 3 weeks conditioning, relative creep and creep modulus using the four points flexural creep test in 20% maximum of deflection load were measured. Results indicated that, the effects of altitude on creep parameters was significant so as the maximum and the minimum relative creep observed in 800 and 400m altitudes, and the maximum and the minimum creep modulus observed in 400 and 800m altitudes, respectively. Analysis of variance (ANOVA) results indicated that the altitude has significant effect on the flexural strength and modulus of elasticity, which in turn caused decreasing the creep parameters.