Retrofitting of existing steel-concrete beams using innovative blind bolts

Recent research shows that the percentage of structures reaching their design life in Australia has increased. Alternative structural solutions that can extend their design life will improve the economy and the sustainability of these structures. Therefore methods of retrofitting and strengthening of existing structures have become very important. The feasibility of utilising two novel types of blind bolt shear connectors in retrofitting of existing non-composite steel-concrete beams has been investigated. Seven steel-concrete beams including three composite and four non-composite beams were cast. The composite beams were constructed utilising three different sheer connector types including the conventional welded headed studs and the two blind bolt types discussed in this paper. Three of the non-composite beams were retrofitted using the same three connector types and the other non-composite beam was used as a control beam. The beams were tested under flexural loading condition. The global behaviour and capacity of the beams in relation to their stiffness, strength and ductility were evaluated. The ability of each shear connector type to achieve composite action in new and retrofitted composite beams was assessed using the global behaviour and capacity of the beams. This paper presents and discusses the results of this series of beam experiments.