Numerical Modeling of Concrete-Filled FRP Tubes' Dynamic Behavior under Blast and Impact Loading

A major difficulty of the analysis of and design for close-in blasts is the high variability of the blast shock waves and the complex interactions between these waves and structures. Close-in blasts also tend to be severe loads that may cause extensive damage to a structural member. If the member in question is a load bearing column, its destruction may lead to a catastrophic progressive collapse of the structure. Thus any improvement on the performance of columns under close-in blast loading is a valuable addition to knowledge. This paper outlines a numerical model built using commercially available software to predict the response of concrete filled fiber reinforced polymer (FRP) tubes (CFFTs) and regular round reinforced concrete members to impacts and close-in blasts and determine the factors influencing their response. The models were verified against drop weight impact test lab measurements and single degree of freedom blast analyses. A parametric study was conducted using the verified models to investigate the effects of diameter, reinforcement ratio, and size of the blast on the response of CFFTs. It was found that the peak displacement response was inversely proportional to all three parameters. The results of the parametric study were used to construct new pressure-impulse diagrams for experimentally tested CFFT specimens that reflect the increased capacity of such members to blast loading. (C) 2015 American Society of Civil Engineers.