Strengthening and rehabilitation of deteriorated timber bridge girders

Research has shown that strengthening of degraded rectangular timber is possible via the use of Fibre Reinforced Polymers (FRP). Tests were conducted at James Cook University (JCU) using three round timber girders removed from a railway bridge in North Queensland, Australia. These were retrofitted with either a Carbon Fibre Reinforced Polymer (CFRP) or Glass Fibre Reinforced Polymer (GFRP) composite in one of three different strengthening profiles. Due to extensive deterioration, two of those girders failed during preliminary tests and thus were repaired as opposed to strengthened. The repaired members sustained enhanced moment capacity and ductility from their initial failure values. The unbroken girder when strengthened, produced a 30% reduction in deflection for the same moment while bending stiffness was increased by 30% from its initial un-strengthened state.