Recent developments of strengthening techniques for metallic structures

This paper introduces the most recent techniques that have been developed for pre-stressed strengthening of metallic members. Details of utilization of new advanced materials such as carbon-fibre reinforced polymer (CFRP), NiTiNb- and Fe-shape memory alloys (SMAs) and hybrid SMA/CFRP for pre-stressing existing metallic members are given. The paper begins with presenting the works on strengthening of metallic members using pre-stressed bonded CFRP material. Furthermore, a pre-stressed un-bonded retrofit system is described. The paper continues with explaining a new strengthening method using un-bonded pre-stressed Fe-SMA strips. Finally, an innovative prestressing system that uses a hybrid system of NiTiNb-SMA/CFRP material is presented. At the end, the paper provides some suggestions for future studies on this topic.