Analyses and Simulations of Axially Loaded RC Walls Subjected to Airblast Load

Wall elements of reinforced concrete in ½ scale, with axial loading, were tested with transversal blast load in an explosive shock tube facility. The experiments provided valuable data for the analyses of structural behaviour, incl. failure modes, for this type of structures. With the experimental results, analyses and simulations are performed in for future development of a reliable methodology for FKR code [1] to deal with this specific application. The analyses show that wall elements with an axially applied load have a decreased deflection when subjected to air blast loading, compared to those without the axial load. The deformation due to air blast for the axially loaded wall elements decreases at an increased axial load level. The failure mode of wall elements has been observed to be consistent with the bending dominant mode even at the increased blast loading level. At the critical condition, catastrophic failure is observed without any residual strength remaining in either axial or transversal directions. The midpoint displacement of the wall elements showed a good correlation with the impulse density in the blast tests. The axial force increases during both the air blast and quasi-static transversal loading conditions. In some cases, the axial force is reduced to below the initial value at large transversal, i.e. horizontal, deformations. Numerical methods, e.g. finite element analyses, are performed to evaluate both dynamic, i.e. blast loading, and quasi-static experiments since both axial and transversal forces vary simultaneously. The area of interest in this study is the evaluation of numerical methodologies to predict the structural behaviour at combined blast load and axial force on a structural member, e.g. a reinforced concrete wall or column. It is shown that additional data, both experimentally and numerically, are needed in the development of a future damage assessment methodology for axially loaded concrete walls and columns.