Alik Duju, Takashi Nakai, Hirofumi Nagao & Toshinari Tanaka Nondestructive Evaluation of Mechanical Strength of Sarawak Timbers
An acceptable method of estimating timber strength has to be established to develop confidence in using timber as construction material. In this study, six methods of measuring modulus of elasticity viz., E_fr, E_usw, E_dwf, E_dwe, E_app and E_tru were compared and used to predict the bending strength of structural size timber. A total of five-timber species viz., Parashorea macrophlla, Gonystylus bancanus, Shorea albida, Dipterocarpus rigidus and Cotylelobium burckii were used in this study. The coefficient of correlation between E_fr, E_usw, E_dwf, E_dwe, E_app and E_tru and MOR were obtained. It was found that the six moduli of elasticity could be used as a parameter to predict the bending strength of 50 mm by 100 mm structural size timber tested at air-dried condition. Amongst the methods used, Efr was found to be more reliable, easy and convenient to use.