Comparative study of shear strength parallel to grain of wood according to the methodologies of ABNT NBR 7190:2022

The present study aims to compare the characteristic values of shear strength parallel to grain obtained through different test methods described in Documents 3 [1] and 4 [2] of ABNT NBR 7190:2022. Compression and shear parallel to grain tests were carried out on specimens from five Brazilian wood species, in order to classify the batches according to their compression strength, to compare the test methods for determining shear strength parallel to grain, as established in the referred documents and evaluating the relationships between shear and compression strengths parallel to grain proposed by the Brazilian standard. The experimental program used batches composed of thirty-six specimens, twelve of which were assigned to compression parallel to grain tests and determination of apparent density, and the remaining twenty-four to shear parallel to grain tests, with twelve used for each test method. Strength characteristic values were determined, statistical equivalence between the methodologies was evaluated, and the existence of a correlation between compression and shear was verified. The results show that the methodology of Document 3 [1] provides significantly higher strength values than those obtained with the methodology described in Document 4 [2], and that there is no statistical equivalence between the two test methods.