Prediction of Bearing Capacity of Closely Spaced Footings: Multilayer Geogrid-Reinforced Pond Ash Perspective

To counter the scarcity of available construction sites, infrastructure industry considers closely spaced footings as one of the viable options. The present study investigated the load–settlement behavior of two closely spaced footings resting on a multilayer geogrid reinforced pond ash bed. A detailed numerical analysis was carried out where the influences of various parameters such as footing shape, spacing between two footings, and number of geogrid layers on the load–settlement behavior are studied. Irrespective of the reinforcing conditions, two closely spaced rectangular footings were observed to exhibit better load–settlement response compared to square footings. This phenomenon can be attributed to the interference of pressure bulbs along with the increase in the base area of rectangular footings. Following numerical investigation, nonlinear regression analysis was performed to develop closed-form expressions of the bearing capacity values. These expressions will enable the practitioners to effectively predict the bearing capacity of closely spaced footings resting on reinforced pond ash bed, well before the construction stage. Finally, the usage of multilayer geogrid reinforcement in devising a pond ash bed into a sustainable foundation material for closely spaced footings, was demonstrated.