Behaviour of cold-formed dimpled columns under lateral impact

•Response of dimpled columns subjected to lateral impact loads was numerically predicted.•The effects of axial pre-compressive loads and fixture conditions were analysed.•The mean residual force of dimpled columns was up to 32.5% higher than plain ones.•The crush efficiency of dimpled columns were up to 24.4% higher than plain ones.•The introduced dimpled geometry contributed in increasing the crush efficiency.