Behaviour of nailed timber box beams

Abstract

Experimental investigations on nailed built up timber box beams of different cross sectional profiles in which the flanges and webs are both entirely of timber are carried out with the objective of understanding the behaviour of the different nailed built up beam configurations and identify their potential as an alternative to the use of solid timber beams. In particular the effect of web thickness, overall depth and shape of flange on the load carrying capacity and flexural rigidity of timber box beams are investigated. Timber beams consisting of webs of 25 mm thickness and overall depth of 225 mm are the most cost effective. The profile of the flange does not have a significant effect on either the load carrying capacity or flexural rigidity. It is observed that flexural rigidity and load capacity are better correlated with the second moment of area and section modulus of only the webs of the box beam rather than that of the entire box beam.