EFFECTS PRODUCED BY NOTCHES IN THE OUTER THIRDS OF THE SPAN OF STRUCTURAL TIMBER BEAMS
Abstract
Very often, timber beams are notched to facilitate support, make connections between structural parts, and others. However, the abrupt change in cross-section creates stress concentrations around the notch. In order to correct these effects, several wood design standards provide special recommendations. The results of several numerical simulations of different cases of notched beams were presented in this work focusing in the analysis of stresses and displacements. It was also evaluated the effects produced by the notches in the beams, by comparison with those obtained by the classical equations of Strength of Materials. The numerical analysis was based on the finite element method, by ANSYS® software. Considering the numerical singularity at the corners of the notches, the submodeling technique associated with the plasticity of the material was used to achieve results convergence. It was also made a comparison between the correction factors obtained in this paper with those proposed by the analyzed standards for wooden structures. Among the analyzed standards, the Brazilian ABNT NBR 7190:1997 was the poorest in specifications and justifications, and it would be interesting that it limit the dimensions of the notches in the outer thirds of the span similarly to American and Chilean standards. Keywords: notch, abrupt change in cross-section, Finite Element Method, numerical simulation, notched beams.Downloads
Published
2016-09-09
Issue
Section
Civil Engineering