Abstract:
There are variety of ways to retrofit timber structures. However, some methods induce
change of the appearance. So, in this research timber beams are strengthened with carbon fiber
sheets. This new method can improve the flexural performance of timber beams without changing
the appearance of it.
In this study, the research divides two parts. The first part is testing the mechanical
properties of timber samples. The second part is testing ten timber beams. Two timber beam
samples are strengthened with carbon fiber reinforced polymer (CFRP) sheets. Four timber beams
are strengthened by CFRP sheets with prestressing. Two timber beam samples with small damage at
mid-span are repaired and strengthened by CFRP sheets with prestressing and other two timber
beams are un-strengthened.
The results showed that, the maximum bending moment of timber beams strengthened by
CFRP sheets with prestressing force of 14550 N is about 62.67 percent more than that of timber
beams without strengthening. The maximum bending moment of timber beams strengthened by
CFRP sheets with prestressing force of 5820 N is about 48.54 percent more than that of timber
beams without strengthening. The defection at failure point of timber beams strengthened by CFRP
sheets with prestressing force of 14550 N is about 22.61 percent less than of timber beams without
strengthened. The defection at failure point of timber beams strengthened by CFRP sheets with
prestressing force of 5820 N is about 46.25 percent less than of timber beams without strengthened.
Timber beams strengthened with prestressed CFRP sheets have higher flexural capacity and less
deflection when compared with timber beams strengthened by CFRP sheets without prestressing.