Bending Creep Behavior of Hornbeam Wood

This study examined the effect of altitude on bending creep behavior of hornbeam lumber (Carpinus betulus). For this purpose, 9 hornbeam trees from three different altitudes (400, 800 and 1100 m) in the northern forests of Iran were selected. Clear samples were cut from mature wood in diameter at breast height (DBH). 108 prepared samples (dimensions: 2.5 × 2.5 × 41 cm) were conditioned at room temperature of 20 ºC and two relative humidities (RH) of 65 % and 95 %. First, the maximum bending load was determined by three-point static bending tests in acclimatized room and then flexural creep parameters, such as relative creep, creep modulus and creep factor, at 20 % of the maximum bending load, were calculated. Results indicated that at 65 % RH, the effect of altitude on creep parameters was significant. The maximum values of relative creep and creep factor were observed at the altitude of 800 m, and the minimum values at the altitude of 400 m. The maximum values of creep modulus were observed at the altitude of 400 m and the minimum values at the altitude of 800 m. Also, at 95 % RH, the effect of altitude on creep modulus was significant but it was not significant on relative creep and creep factor. The maximum creep modulus was observed at the altitude of 400 and the minimum at the altitude of 800 m.