Strain Rate-Dependent Structural Behaviour of Masonry Structures Loaded by the Impact Force of Waterborne Debris Evaluated According to ASCE/SEI 7–22 Design Prescriptions

As confirmed by recent post-disaster surveys, masonry buildings may experience substantial damage under waterborne debris impacts in extreme hydrodynamic event scenarios, e.g., floods or tsunamis. The common approach to model such load scenarios is to carry out structural analyses where the debris action is implemented through a representative force-time diagram. Recent studies demonstrated that the strain rate-dependent structural behaviour is activated in masonry structures when subjected to the impact force of waterborne debris, making the implementation of the strain rate-dependent materials necessary to carry out reliable structural simulations. However, these data have been collected using a specific model to compute the impact force-time diagrams developed from numerical and experimental data, which is different from the model prescribed by the US standard ASCE/SEI 7–22 to compute such loads. These two models lead to different force-time diagrams. Therefore, the design strategy imposed by the ASCE standard might affect the high strain rate effects with unknown implications. This study aims to investigate this research gap using nonlinear Finite Element (FE) simulations. A masonry wall is modelled with a micro-modelling approach. The water flow pressures and the debris impact force are applied. It is found that the F-t diagram given by the ASCE model causes significantly different strain rate-time histories in terms of increment rate and peak values across the structure.