Study of Pressure-Impulse Diagrams for Reinforced Concrete Columns Using Finite Element Analysis

Abstract

The failure of reinforced concrete columns when subjected to blast events can be catastrophic to the building as a whole. The choice of the type of lateral confinement may influence the response of columns subjected to blast load much more when compared to the application of traditional loads. The objective of the research reported in this paper is to study the non-linear response of a typical reinforced concrete column with four types of lateral reinforcement subjected to uniform blast loading, using finite element (FE) and single degree of freedom (SDOF) methods. An advanced FE modeling tool, LS-DYNA and a widely used SDOF analysis tool – SBEDS – are used for this purpose. Pressure-Impulse (PI) diagrams for different levels of protection (LOP) are developed using both the methods. The mid height displacement is used to represent the levels of protection. A parametric analysis is used to develop PI diagrams in order to study the effect of confinement on the reduction of displacement at impulsive, dynamic, and quasi-static loading conditions. PI curves developed from the FE methods are compared with the curves from the SDOF methodology. Regression equations are also developed using statistical analysis, to characterize PI diagrams generated from the FE method. Recommendations for analysis, design and detailing of reinforced concrete columns for blast protection based on this research are presented.