BENDING PROPERTIES OF SPACED WOODEN BEAMS

The objective of this study was to investigate the bending properties of spaced wooden beams using dimension lumber, that is, 2 in. by 4 in. and 2 in. by 6 in. lumber. The test specimens were constructed in 12 combinations with various spacer-block sizes and connection methods as shown in Table 2. Bending tests of these beams were performed under c entral loading conditions, and test results were examined in relations hip to the above combination factors. The bending properties and the s tress distributions of the spaced beams were analyzed numerically acco rding to Tsujii's theory and also according to the finite element meth od (FEM). The experimental results on the bending properties and the s tress distributions were compared with the calculated ones. As experim ental results, the flexural rigidities of the spaced beams increased w ith increases of the spacer-block lengths and the spacer-block heights , and the maximum bending moments increased with increases of the spac er-block heights. Comparing the metal-plate connected spaced beams wit h the glue connected spaced beams, the flexural rigidities of the form er were almost equivalent to those of the latter, and the maximum bend ing moments of the former were nearly 1.8 times greater than those of the latter. The flexural rigidities and stress distributions of spaced beams predicted by the FEM agreed well with the experimental values. The shear stress concentrations were confirmed along the glue lines be tween the chords and spacer-blocks near the void spaces of the beams.