BENDING STRENGTH OF HYBRID COMPOSITE BEAM OF TIMBER AND CARBON FIBER REINFORCED PLASTIC SHEET

Abstract

 Nowadays, construction of buildings with wood structure is gaining momentum since the Diet introduced a policy to promote the use of wood for public buildings in 2010, and the demand for long wooden beams with a large cross section is increasing. In this study, we tested hybrid composite beams made up of square timbers of Sakhalin fir that were put together with laterally glued CFRP sheets and their bending performance was evaluated. A series of bending tests on hybrid composite beams is reported, of which the test parameters are arrangement of CFRP sheets, presence of butt joint of composing timbers, and that of lateral adhesion between timbers. For the type in which the CFRP sheet was arranged vertically in the cross section of the beams, absence of lateral adhesion between timbers did not lower the bending strength. The type in which two CFRP sheets were arranged vertically in the cross section and externally glued on the tension side of the beams and composing timbers had butt joints exhibited 95% higher bending strength than that without CFRP sheets. These results exhibited potential of hybrid composite beam of timber and CFRP sheet on the production of wooden beams with a large cross section for lengthening of products and labor saving.