Résistance à l'enfoncement du pin gris en fonction du taux de chargement et des conditions de service

Authors: Cousin, Antoine
Advisor: Mohammad, MohammadSalenikovich, Alexander
Abstract: Understanding and predicting the effect of load duration and ambient conditions on mechanical behavior of wood is an important subject in wood engineering. The aim of the study is to establish the influence of the rate of loading on the embedding strength of wood in various service conditions. The experimental part of the project consists of measuring the embedding strength of wood parallel to grain. Jack pine specimens (Pinus banksiana) of 31×89×660 mm are assembled using one bolt of 12.5-mm in diameter and two 6-mm thick steel side plates at each end. Specimens are assembled after conditioning to one of the following equilibrium moisture contents (MC): 1) green, at least 24 % MC, 2) air-dry, about 12 % MC, and 3) very dry, about 8% MC. Seven rates of loading, varying between 115 KN/min and 0.1N/min, are applied to the specimens in each moisture condition. Given the heterogeneity of the material, the test pieces are matched using visual grading and density distribution to attribute similar wood quality to each test series. Elastic stiffness, proportional limit, yield point, the maximum resistance, MC and specific gravity are determined for each embedding zone after the test. A comparison between test values and empirical equations for duration of load is presented in this study. At 12% MC, embedding strength shows an equal behavior for duration of load, similar to bending and compression. The loss of the dowel embedding strength is analyzed and correlated to the strength values and the adjustment factors of the Canadian, European and American wood design codes. Predictions of the North-American codes appear to fit the results of this research based on 10-min reference test duration.
Document Type: Mémoire de maîtrise
Issue Date: 2012
Open Access Date: 18 April 2018
Permalink: http://hdl.handle.net/20.500.11794/23290
Grantor: Université Laval
Collection:Thèses et mémoires

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