Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
2 results
Search Results
Item Geofoam integrated separation layer for enhancing seismic resilience in modified piled raft foundations(Springer Science and Business Media B.V., 2024) Amalu, P.A.; Jayalekshmi, B.R.Modified Piled Raft (MPR) foundations have the potential to reduce seismic force transmission to the superstructure compared to connected piled raft foundations. However, the responses of the separation layer in improving the seismic resilience of the structure were not extensively parameterized before. To address this gap, the investigation explores the potential for enhancing the seismic resilience of MPR foundations in seismically active regions by integrating sustainable materials in the separation layer between the raft and pile group. A novel separation layer is proposed by integrating geofoams with different types of soils. The performance of this novel separation layer is explored through a comprehensive 3D finite element analysis under both static and dynamic loading conditions. Using the OpenSees software platform, an extensive numerical analysis was undertaken to examine the influence of various key parameters on the system's behaviour. A comprehensive analysis of these parameters was conducted to evaluate the responses of MPR foundations with and without geofoam in the separation layer, specifically in the context of ground motion analysis. Raft thickness, pile configuration, separation layer thickness, and the materials used in the separation layer were all considered. The findings indicate that raft thickness and pile length are crucial influencing factors on the dynamic response of the MPR system. Furthermore, the inclusion of EPS geofoam in the separation layer demonstrated its effectiveness in reducing the acceleration amplitude at the top of the raft by 44.25% and lateral displacement by 47.84%, effectively mitigating the impact of seismic waves reaching the upper surface of the raft. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.Item Influence of Separation Layer Properties on Seismic Response of Modified Piled Raft Foundations(Springer, 2025) Amalu, P.A.; Jayalekshmi, B.R.Conventional piled raft foundations, with the raft and piles interconnected, severely restrict lateral movement, especially during seismic events. These constraints result in substantial stresses at the connection, posing a risk of potential breakage. Therefore, in seismic-prone areas, where transient lateral loadings of larger magnitudes are expected, conventional piled raft foundations are not feasible. Providing a separation layer between the raft and pile foundations is a viable solution to improve the performance of conventional piled raft foundations. The performance of such a modified piled raft system depends largely on the properties of the separation layer introduced. However, limited studies have been conducted to evaluate the seismic performance of these separation layers by considering the effect of soil–structure interactions. The present study thus aims to investigate the performance of modified piled raft systems by comparing them with their conventional counterpart. The existing conventional piled raft foundation of the Treptower building has been chosen as the prototype and is numerically analysed for static and dynamic loading conditions. Further, a separation layer has been introduced between the pile and raft, and the performance of the modified piled raft foundation is analysed under similar loadings. The results of these analyses are comprehensively compared to ascertain the performance of modified piled rafts under seismic excitation. It is found that the modified piled raft foundation with PE foam in the separation layer is advantageous in damping the propagation of seismic waves to the superstructure, reducing settlement and lateral displacements, and thereby decreasing the potential risk of failure of superstructures in seismic-prone areas. © The Author(s), under exclusive licence to Indian Geotechnical Society 2024.