Flexural performance of bamboo scrimber beams strengthened with fiber-reinforced polymer

•A new type of bamboo scrimber beams is proposed.•The failure of the strengthened beams starts with tensile fractures.•Load-carrying capacity and rigidity of the strengthened beams are increased.•A theoretical method for predicting the load carrying capacity is developed.

This study presents a new type of bamboo scrimber beams that are strengthened by fiber-reinforced polymer (FRP) composite sheets embedded in the internal tensile region with an additional bamboo plate. To investigate the flexural performance of the bamboo scrimber beams, four-point bending tests were conducted to determine the failure modes, the load-displacement relationship, the load carrying capacity and the flexural rigidity of reinforced bamboo scrimber beams. The main parameters in the tests were the number of FRP layers and the type of FRP. The results indicated that the failure of the strengthened beams started with tensile fractures on the bottom bamboo plates, and no slipping was observed between the strengthening materials and the original bamboo beams prior to the rupturing of the bamboo plates. The flexural load-carrying capacity and the flexural rigidity of the strengthened beams effectively increased due to the FRP composite sheets and an additional bamboo plate. The strengthening method has a beneficial effect on promoting the compression behavior in the compression zone of the cross-sections of bamboo beams. Based on a simple stress-strain model of bamboo scrimber, a theoretical method for predicting the flexural load carrying capacity was developed. The predicted results are consistent with the test results.