Performance of timber stringers reinforced with GFRP wraps

The large amount of timber bridges in North America that are at the end of their service life has driven new attention to the study of effective ways of retrofitting them. Additionally, recent use of fiber-reinforced polymer (FRP) materials in civil engineering applications makes them an interesting alternative for this application because of their lightweight and non-corrosive nature. Glass fibre-reinforced polymer (GFRP) fabrics used for strengthening of aged timber stringers are studied in this research program and compared to GFRP bar systems which have been studied and used successfully in the past for this application. The research program focused on the performance of reinforced stringers containing splits as a result of their aging process.; The research program considered 3 different aspects of the behaviour of aged stringers externally reinforced using GFRP sheets. (1) The effectiveness of different patterns of shear reinforcement on split elements was studied using a direct shear test, (2) the flexural behaviour of reinforced samples was studied using full-scale stringers with dap ends reinforced with GFRP sheets and tested in 3-point bending, and (3) the long term behaviour of the reinforcing system was studied using a durability test.; Results from this work show the effectiveness of the external reinforcement to retrofit aged timber stringer; additionally, the low variability in results from the bending test on externally reinforced samples gives excellent results in terms of reliability. On the other hand, results from this research program indicate the need to study the long term performance of the reinforcement technique using surface bonded GFRP sheets. (Abstract shortened by UMI.)...