Avaliação do módulo de elasticidade de peças estruturais roliças e de corpos-de-prova de Pinus elliottii

Abstract

Brazilian code NBR 7190:1997 – Design of timber structures, ABNT, specifies that structural design can be done using data obtained from small wood specimens. However, natural characteristics present in structural timber, as knots, may affect mechanical properties. The aim of this study is to evaluate modulus of elasticity obtained in compression parallel to grain and static bending tests, carried out for small wood specimens and structural round timber of Pinus elliottii. Twenty four small wood specimens and twenty four structural round timber pieces were submitted to compression parallel to grain, and twenty four small wood specimens and twenty four structural round timber pieces were submitted to static bending. ANOVA analysis indicates that there is statistical difference for MOE in static bending: 7.724 MPa (average) was obtained for small wood specimens versus 9.594 MPa for structural pieces. There is also a difference in compression parallel to grain tests: 11.596 MPa (average) was obtained for small wood specimens versus 8.077 MPa for structural round timber. As conclusion, the use of data obtained in compression parallel to grain (the standard test reference in NBR7190:1997 for structural design) in small wood specimens may lead to an unsafe structural timber design, due to low values obtained in structural round timber compared to small wood specimen values.