Many timber beams may require strengthening due to either the changing of usage or an increase of loading. This paper reported an experiment in which six timber beams were tested, including three reference unstrengthened timber beams and three timber beams strengthened with bamboo strips.The test results showed that the ultimate flexural strength of timber beams increases by 48.0%-83.1% after strengthened by a few externally bonded small bamboo strips. The stiffness of the strengthened beams also increases significantly. The strain distributions along the height of the strengthened beams at middle-span are nearly linear during the whole loading process, that is, a plan section remained almost plan. The strains in the bamboo strips at different position across the width on the tensile face of the beams are very close. This study showed that strengthening timber beams with bamboo strips is a very promising low-carbon and effective technique.
