A new approach to optimizing the geogrid layout to maximize the bearing capacity of strip footing

This study presents a new approach to optimizing the layout of the geogrid layers to achieve the maximum bearing capacity of the strip footing under different loading conditions (Vertical (V), Horizontal (H) and eccentric (M) loads) using a numerical method. To find the best location of the geogrid layers in the current method, the optimum depth of each layer is obtained separately, which was not considered in previous studies. The effects of parameters such as different loading combinations, numbers and layout of geogrid layers on the ultimate bearing capacity of the strip footing have been studied. The results of the analyses are plotted in the form of dimensionless graphs. For different loading combinations, the optimum layout and number of reinforcing layers have been determined. The results show that the presence of the reinforced layers, at the optimum layout, significantly increases the ultimate bearing capacity of the strip footing, especially in the V and VM loading conditions. The optimum number of geogrid layers was different for different loading conditions. Based on the analyses, 7, 4 and 4 geogrid layers were obtained as the optimum number of reinforcement layers for the V, VH and VM loading conditions, respectively. Also, it was found that the position of each layer depends on the number of layers. In this study, the position of the first layer from the foundation (u/B) was varied by increasing the number of reinforcement layers and the loading conditions. In the VM loading condition, the geogrid reinforcement effect on the bearing capacity is more prominent with respect to the VH loading conditions. The increase of the bearing capacity in the VM loading condition at the optimum layout of reinforcement (N = 4) is about 100 %, compared to the bearing capacity of the unreinforced soil.