Numerical modelling of masonry wall response to blast loads

Abstract

Masonry walls are commonly used in both residential and office buildings as either load-carrying structural components or partition walls. Failure of a load-carrying masonry wall to terrorist bombing attack or accidental gas explosion could result in collapse of the structure. The debris generated from the failed masonry wall will also impose great threats to the building occupants. Therefore dynamic response and failure of masonry walls to blast loads must be evaluated for safety assessment of building structures. In this study, a recently developed homogenised orthotropic masonry material model with strain rate effect is used to model masonry material damage. The model consists of a pressure-sensitive strength envelope, an equation of state and a double exponential damage model. In addition, an innovative approach based on the combined facture mechanics and continuum damage mechanics theory is used to estimate the masonry fragment size distributions. The method estimates masonry wall fragmentation process in two steps to avoid eroding away the masonry material. Numerical simulations of a 2.88 x 2.82 m masonry wall to blast loads generated from TNT explosions of different weights and at different standoff distances are carried out. The material strain rate effects on masonry wall dynamic responses are discussed. The numerically predicted masonry fragment size distributions are also presented.