STUDY ON THE BEHAVIOR OF REINFORCED CONCRETE COLUMNS WITH FIBER MODEL CONSIDERING STRAIN RATE EFFECT

In this study, dynamic tests on reincorced concrete (RC) column specimens subjected to high rate loadings are carried out. Two dynamic constitutive models of concrete proposed by CEB code and Kulkarni and Shah with the consideration of strain rate effects are adopted for the fiber model of RC columns, and a dynamic fiber model for the specimens is constructed and employed to study the dynamic performance of the RC column specimens. Simulation results by the two constitutive models show good agreements with the test results. The results also show that lateral load capacity of the RC columns increase with loading rate, and the proposed dynamic fiber element model provides a convenient way to predict the behavior of RC columns under the considered loading rates. The validated dynamic fiber element model is employed for further numerical study of the dynamic monotonic properties of two of the considered RC columns under different axial compression ratios and subjedted to different loading rates. Results show that dynamic load-carrying-capacity of the specimens increase with the increase of the loading rates. Moreover, the employed two dynamic constitutive laws give close load-carrying-capacity results under low loading rates with corresponding strain rates lower than about 104/s, but differences exist under relatively higher strain rates. The load-carrying-capacity by CEB code is relatively higher.