Influence of test methods on the parallel to grain embedment strength and foundation modulus characterization

Abstract

Different test setups have been reported in the literature for the determination of the embedment strength in timber elements. These variances hinder a straightforward comparison between available test data. It is difficult to determine if the source of variability lies in intrinsic timber properties or is related to the test protocol used. This paper aims to provide a better insight into the influence of embedment strength test methods, comparing experimental results from different test setups within the guidelines of EN 383 and ASTM D 5764-97a for Scots pine wood (Pinus sylvestris) and Spruce (Picea Abies). A robust statistical analysis was performed to identify statistically significant differences between the groups evaluated. The analysis of the parallel to grain embedment strength showed that the results differed between standards, pointing out the potential bias inserted in the embedment properties given their evaluation method. Moreover, the thickness of the specimen tests also proved to influence the yield and ultimate embedment strength for the wood species tested.