MODELING OF ARCHING UNREINFORCED MASONRY WALLS SUBJECTED TO BLAST LOADINGS

Abstract

<p>Masonry is one of the most commonly used materials in building construction throughout the world. Unreinforced masonry (URM) walls typically have very low flexural capacities and tend to posses brittle failure modes. Due to brittle nature of URM walls, it is critical to predict the behaviour of the wall when exposed to extreme out of plane loadings such as blast loads. An effective way to enhance the ability of unreinforced masonry walls to withstand blast loads and consequently to limit the amount of wall damage is imposing arching mechanism on the wall. Since carrying out physical experiments to study the response of URM walls subjected to blast load is both dangerous and expensive, finite element modeling has become more attractive to researchers. In this research, an unreinforced one-way arching wall is simulated using the finite element program LS-DYNA and its behaviour subjected blast loading is studied. The model is constructed based on the data recorded earlier during a physical blast experiment. Close agreement was observed between the numerical and experimental results which validated the developed model. A sensitivity study is then performed where the influence of variation of some input parameters such as mortar strength, coefficients of friction, scaled distance, boundary condition, wall height and the effect of two-way arching action on the wall’s response is evaluated. The most influential parameters in this study found to be the scaled distance, wall height and two-way arching action. Smaller scaled distances result in high deflection and as the scaled distance increases the maximum deflection decreases. The wall height also significantly affect the wall’s response to blast loads, i.e. the taller the wall the larger the maximum displacement. It is also concluded that two-way arching action can significantly reduce the wall’s maximum deflection.</p>