Loading rate effects on CFRP strengthened steel square hollow sections under lateral impact

This paper discusses the experimental results of carbon fibre reinforced polymer (CFRP) strengthened square hollow sections (SHS) under different loading rates. The experiments comprised a series of SHS columns tested under two loading rates: quasi-static (0.05 mm/s) and impact (4.43 m/s). Some of these columns were strengthened with different CFRP configurations comprising fibres oriented in the longitudinal direction, transverse direction and in both directions. The effect of co-existing axial compression applied prior and during the application of the transverse load (impact or quasi-static) was also examined. The axial load was introduced in the experimental program to simulate the normal service load that exists on columns in multi-storey frame buildings. Generally, it was found that the effectiveness of CFRP strengthening was increased at a higher loading rate to different degrees depending on the CFRP configuration.