Piled footings in weakly bonded residual soils: field performance and numerical insights

Piled footings are combined foundation systems that consider the interaction between soil, footing and piles, offering technical and economic benefits over separate use of footings and piles. This study investigates the behaviour of piled footings on lightly bonded residual soil through five full-scale load tests and numerical modelling. Results show that incorporating the footing’s contribution in pile groups and adding piles beneath isolated footings effectively reduces settlements and increases load capacity. These methods can reduce foundation costs, making them suitable alternatives for small and low-cost housing in developing countries. Numerical modelling revealed that footing contact with the ground decreases friction mobilisation at the pile tops, while the presence of piles reduces the footing’s contact area with the soil. These interactions decrease the individual performance of piles and footing, but much of the effectiveness of the components is maintained. This highlights the technical feasibility and potential advantages of piled footings in residual soil. The study also shows that the overall performance of the combined system can be estimated by analysing the individual contributions of the footing and piles.