The strain rate effect of reinforcing steel bars is generally indispensable for modeling\nthe dynamic responses of reinforced concrete structures in blast and impact events. A systematic\nexperimental investigation was conducted on the strain rate behavior of reinforcing steel bar grades\nHPB235, HRB335, HRB400, and HRB500 which are widely used in the field of civil engineering in\nChina. The dynamic testing was performed using a servo-hydraulic Instron VHS160/100-20 in a\nstrain rate range from 2 to 75 sâË?â??1. Stress-strain curves at preset strain rates were obtained. The test\ndata were then used to derive the parameters in a model based on the dynamic increase factors (DIFs)\nof strengths and the Johnsonââ?¬â??Cook constitutive model. Results indicated that a significant strain rate\neffect was observed for the four rebar grades. The dynamic yield strengths increased from 13% to 41%\nand their ultimate strengths improved from 9% to 19% in the strain rate range during testing. The\nstrain rate behavior of the four rebar grades could be appropriately predicted using the parameters\nin the model based on the DIFs of strengths and the Johnsonââ?¬â??Cook model.
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