Influence of soil-pile foundation-structure interaction on the ductility capacity of RC buildings,
Authors :- N Sharma, K Dasgupta, A Dey
Publication :- Structures (Elsevier), Volume 77, 2025
A surge in the infrastructure development, in populated regions, has compelled the construction of Reinforced Concrete (RC) buildings to be made over pile foundations when the underlying soil deposit is weak or loose. Individual piles in the foundation system can exhibit significant inelasticity and contribute to the modification in the inelastic response and ductility of the building system. Very limited studies are available that investigate the influence of soil-pile foundation structure interaction (SPFSI) on the inelastic seismic response of RC buildings. Existing studies on building with pile foundations consider the inelastic behaviour of the soil without accounting for pile inelasticity. Moreover, studies assessing the influence of SPFSI on the ductility of RC buildings are scarcely available. This article investigates the role of the complex phenomenon of SPFSI in modifying the inelastic behaviour and ductility capacity of RC frame and RC wall-frame systems. The results from this study show that the soil-pile foundation system inevitably contributes to the lateral load behaviour of RC buildings through inelastic deformations and rocking of the pile groups. This modifies the inelastic superstructure response in terms of the yield and ultimate drifts which may lead to a decrease in the ductility capacity of the RC buildings. In the present study the decrease in the ductility capacity was observed to be as high as 39 % for RC wall-frame system and 12 % for RC frame systems. The obtained results imply that, in order to account for the reduction in the ductility capacity of RC buildings under SPFSI effects, the response reduction factor needs to be suitably modified while carrying out the seismic design. Overall, this study reflects the importance of considering the complex phenomenon of soil-pile-foundation structure interaction (SPFSI) and its critical contribution towards the modification in the ductility of RC buildings supported on pile foundations.