High Rate-Dependent Interaction Diagrams for Reinforced Concrete Columns

Problem statement: There is a need to better understand the rate dependence behavior of reinforced concrete structures in order to improve their response to impact and blast loads. Analysis and design of reinforced concrete structures subjected to seismic loadings has been recommended in many FEMA guidelines. However, reevaluation of design becomes extremely important in cases where large deformations are expected such as blast and impact resistant. Approach: This study presents a numerical model to evaluate reinforced concrete columns submitted to high strain rates expected for seismic, impact and blast loadings. The model utilizes dynamic stress-strain response and considers the effect of strain rate on concrete strength; strain at peak stress; yield and ultimate strength of steel; and slope of the softening portion of the stress-strain curve. Results: Results are presented in the form of interaction diagrams and compared with the available analytical and experimental results. Comparison with available data shows that the proposed model can give consistent prediction of the dynamic behavior of reinforced concrete columns. Conclusion/Recommendations: The established interaction diagrams may be used to design columns to withstand high velocity impact loads. Also, knowledge gained can be used to improve dynamic behavioral models and computer-aided analysis and design of reinforced concrete columns subjected to severe blast loadings.