08.38: Experimental characterisation of the flexural behaviour of rubberized concrete‐filled steel tubular members: Fid-Bau Portal

08.38: Experimental characterisation of the flexural behaviour of rubberized concrete‐filled steel tubular members

Silva, António / Jiang, Yadong / Castro, José Miguel / Monteiro, Ricardo

The main objectives of the research presented in this paper are to investigate the flexural behaviour of Concrete Filled Steel Tube (CFST) columns made with Rubberized Concrete (RuC) and to identify the behavioural differences between this type of composite members and typical (standard concrete) CFST members. The influence of the rubber aggregate replacement ratio on member strength, ductility, and energy dissipation capacity is assessed. The paper begins with a description of the preparation and development of the experimental campaign, which involves the testing of 36 composite specimens (28 RuCFST and 8 standard CFST), and a single circular hollow steel tube. The selection of the specimens took into account a number of geometrical and material parameters, namely the shape of the cross‐section (circular, square and rectangular), the cross‐section slenderness and the rubber aggregate replacement ratio. A novel testing mechanism was developed as a part of an innovative testing setup, aimed at reducing both the cost and preparation time of the specimens. The columns were tested under both monotonic and cyclic lateral loading, combined with different levels of axial compression. The monotonic results were compared with the expected flexural capacities according to Eurocode 4, and the cyclic results were used to gauge the sectional slenderness limits of Eurocode 8 for different ductility classes. The test results obtained are indicative of the reduced influence of the type of concrete infill on the monotonic and cyclic flexural behaviour of these composite members, and also allow concluding that Eurocode 4 is conservative in predicting the capacity of the tested specimens. Moreover, it was found that the cross‐section slenderness does not have a significant influence on the monotonic and cyclic behaviour of the specimens, pointing out for the possible relaxation of the cross‐section slenderness limits currently specified in Eurocode 4 and 8.