It is necessary to have a comprehensive understanding of the structural response under collision to design offshore structures against possible accidents. A general procedure based on theoretical analyses to classify the elastic responses of frame structures under collision has been reported by the authors. The details have been shown for simply supported pipes. The responses are divided into three groups depending on the stiffness ratio and the mass ratio, namely one degree of freedom motion, two degree of freedom motion and higher mode vibration. Further, simple mechanical models have been proposed for each type of response. In this report, elastic-plastic responses of simply supported pipes subjected to lateral collision are studied through two series of experiments. The elastic responses are measured in the first series to verify the classification of the responses and the relevant mechanical models which have been reported by the authors. The elastic-plastic responses are measured in the second series to obtain fundamental understandings of real phenomena. Especially, the effect of the strain rate sensitivity of the yield stress upon the phenomenon is examined.