Behavior to compression in slim pieces of glue-laminated poplar wood.

Abstract

This work was raised under the problem of the applicability of the formulas and the admissible critical stresses proposed by INTI-CIRSOC 601 (2016) and the safety coefficient that this yields for slender compressed parts. A test program of 40 pieces of slenderness 90, of structural glued laminated wood of Populus deltoides clones ‘Australian 129/60’ and ‘Stoneville 67’, from the Paraná River delta, was designed. Through the bending test, according to the prescriptions of the IRAM 9663 (2013) standard, the modulus of elasticity (MOE) was determined, resulting in a minimum of 87% higher than that presented by the regulation. Next, the compressed pieces were tested, determining a minimum breaking stress of 6.2 [N/mm²]. The admissible critical stress was determined from the formulas established in INTI-CIRSOC 601 (2016), with the minimum MOE of the supplement resulting in 2.5 [N/mm²] and with the minimum experimental MOE resulting in 4.2 [N/mm²]. A safety coefficient of 2.5 was verified for the admissible critical stress with the MOE values proposed by regulation, and for the actual minimum MOE obtained from the tests, 1.5, resulting in the latter being lower than the premises of the Argentine regulations that use a coefficient of the order of 2. There is a need to carry out a broader series of tests to confirm the real elasticity modulus that deserves to be used in the regulation and to determine the final safety coefficient through a more exhaustive analysis of the regulatory formulas.