Load tests on flitch beams: lessons from history

摘要

It is probable that some readers may wonder how someone could possibly have tested flitch beams in 1859, some 150 years ago. These tests were carried out at Royal Arsenal, Woolwich. An extract reporting the tests has been taken from Tredgold's Carpentry (Hurst, dated 1899) and sent to me by an ex-colleague Charles Shapcott (M). The report belongs to the period when methods for deriving stresses due to bending and shear were not well developed. However, some of the statements are still valid. For example, the report comments on the question of effectiveness of iron and wood combination, on account of the difference in the resistance powers of the two materials. Many designers might still have this doubt and tend to ignore any contribution of timber other than providing stiffness to the iron plate and facility for timber-to-timber connections.