Sensitivity analysis of the numerical simulations of partially grouted reinforced masonry shear walls

Abstract

A simplified finite element (FE) model is proposed using VecTor2 software to simulate the cyclic behavior of partially grouted reinforced masonry shear walls (PG-RMSWs) constructed with concrete-masonry blocks and having reinforced bond beams. The proposed model is validated against different experimentally tested walls available in the literature and is found to be capable of simulating the experimental behavior. Following the development of the validated model, a sensitivity analysis is conducted to study the relative effect of different grouted and ungrouted masonry modeling input parameters on the seismic response of the modeled walls. In this regard, six reference walls with different aspect ratios and different vertical reinforcement spacings are modeled. Afterward, reference values of masonry modeling input parameters are changed within ±30% from the reference values yielding 126 modeled walls. A numerical study is also conducted to compare the response of fully grouted reinforced masonry shear walls (FG-RMSWs) and PG-RMSWs to investigate the differences in their behaviors. In this regard, four walls with different aspect ratios and spacings between vertical grouted cells are considered. For the sensitivity analysis, it is concluded that the parameters of the ungrouted masonry are the most influential ones, where the walls' behavior is primarily sensitive to the input value of the angle of internal friction between blocks and mortar. However, this effect diminishes as the aspect ratio of the wall increases and spacing between grouted cells decreases. Accordingly, for shorter walls and walls with larger spacing between grouted cells, more attention shall be given to the estimation of the parameters representing the material properties of ungrouted masonry, especially the angle of internal friction. This concludes that a better seismic response of PG-RMSWs can be achieved by improving the properties of the block-mortar interface in the ungrouted portions of the walls. Comparisons of the seismic response of FG-RMSWs with PG-RMSWs show that FG walls with a lower aspect ratio have a higher ultimate load and a lower corresponding displacement compared to their PG counterparts. For walls with a higher aspect ratio, both the ultimate load and the corresponding displacement are larger for FG walls.