Experimental study on CFRP-reinforced glulam-concrete composite beams

To investigate the mechanical behaviour of timber-concrete composite (TCC) beams strengthened with carbon fibre-reinforced polymer (CFRP), one TCC beam without CFRP and three TCC beams with different thickness of CFRP were tested under four point bending. During the loading process, the deformation development and failure mode of the composite beams were observed. The strain distribution at mid-span section as well as the relative slip between concrete and glulam was measured. Flexural capacity and stiffness of the composite beam were also analyzed considering the varying thickness of CFRP. Test results show that, the flexural capacity and stiffness increase significantly by CFRP strengthening, and TCC beams strengthened with CFRP show much greater ductility than the unstrengthened TCC beam. With the increased thickness of CFRP, the flexural capacity of the composite beam tends to increase, while with a limit where the composite beam with excessive CFRP fails in shear rather than bending. In addition, the CFRP-strengthened degree has no significant influence on the stiffness and ductility of composite beams.