Hybrid Foundation A New Era in Load Bearing System i.e. Hybrid Foundation

Abstract

India\'s rapid urbanization and diverse geological conditions pose significant challenges to traditional foundation systems. Conventional foundations, such as raft and isolated footings, often struggle to support structures in flood-prone regions, seismic zones, and areas with weak soil conditions. The increasing frequency of natural disasters, soil erosion, and groundwater fluctuations further complicates the stability of buildings and infrastructure. To address these challenges, Hybrid Foundations—a combination of shallow and deep foundation techniques—are emerging as a viable solution in India’s construction sector. These foundations integrate raft slabs with deep piles or piers, ensuring better load distribution, improved settlement resistance, and enhanced structural durability. This technique is particularly relevant for metros like Mumbai, Kolkata, and Chennai, where soft soil and high water tables increase the risk of foundation failure. This paper explores the adoption of Hybrid Foundations in India, analyzing their structural advantages, economic feasibility, and long-term sustainability. Various case studies, including infrastructure projects and high-rise buildings, illustrate their growing importance. Additionally, laboratory tests and field data highlight how Hybrid Foundations reduce settlement by 40–50%, enhance shear strength, and offer better performance in seismic zones. By integrating modern engineering principles with traditional construction methods, Hybrid Foundations provide a resilient and adaptive approach for India’s diverse terrain. This study emphasizes their potential for widespread adoption in commercial, residential, and infrastructural projects, ensuring safer and more sustainable construction practices across the country.

Introduction

Background:
Conventional raft foundations often fail in flood-prone and weak soil areas due to settlement, erosion, and poor load-bearing capacity, risks worsened by climate change. The Hybrid Floating Foundation, combining raft foundations with deep piles, offers improved stability, reduced settlement, and enhanced flood resistance.

Problem Statement:
Raft foundations are cost-effective but struggle in soft, sandy, or waterlogged soils, leading to high settlement, weak shear strength, and erosion. Pile foundations perform better but are costly. The hybrid system aims to balance cost and performance by integrating both methods.

Hybrid Floating Foundation:
This system uses a raft to distribute loads and piles anchored in deeper soil for support, along with soil compaction to increase shear strength and reduce erosion. Advantages include about 50% less settlement, 30% improved shear resistance, double load-bearing capacity, and better flood resilience compared to traditional raft foundations.

Research Gap:
Limited experimental research exists on hybrid foundations in flood-prone conditions, with a lack of comparative data and standardized design methods.

Study Objectives:
To experimentally compare hybrid and traditional foundations using tests like Consolidation (for settlement), Direct Shear (for shear strength), and Standard Penetration Test (for load capacity). Secondary goals include assessing water infiltration effects and practical applications.

Results:

• Shear strength improved from ~30° (traditional) to ~40° (hybrid), indicating better sliding resistance.

• Settlement reduced from 9.5 mm to 4.7 mm, cutting soil sinking by about half.

• Load-bearing capacity roughly doubled, from 9-10 to 22-25 at 1.5 m depth.

Overall, the Hybrid Floating Foundation significantly outperforms traditional raft foundations in stability and load support in challenging soil and flood conditions.

Conclusion

From the tests conducted, it is evident that the hybrid floating foundation (raft + piles) offers significant advantages over the traditional raft foundation. The results clearly show that hybrid foundations enhance stability, reduce settlement, and improve load-bearing capacity, making them a more reliable choice for construction in challenging soil conditions. 1) Better Resistance to Sliding: The hybrid foundation demonstrated a higher friction angle (39°-40°) compared to 30°-31° in traditional foundations, meaning it can better resist lateral forces. This is particularly useful in areas prone to flooding or soil movement. 2) Less Settlement Over Time: The settlement of hybrid foundations was nearly 50% less (4.7 mm vs. 9.5 mm). This means buildings constructed on hybrid foundations are less likely to develop cracks and structural issues over time. 3) Higher Load-Bearing Capacity: The SPT N-Value at 1.5m depth was more than double in hybrid foundations (22-25 vs. 9-10). This suggests that the soil beneath a hybrid foundation becomes much stronger, allowing it to support heavier structures without failure.

References

[1] J. Smith and R. Patel, “Advancements in Foundation Engineering: A Comparative Study of Hybrid and Traditional Foundations,” Journal of Civil Engineering Research, vol. 45, no. 3, pp. 112-128, 2022. [2] A. Kumar and S. Mehta, “Effect of Pile-Raft Systems on Load-Bearing Capacity in Soft Soils,” International Journal of Geotechnical Studies, vol. 38, no. 2, pp. 89-102, 2021. [3] C. Lee and W. Tan, “Mitigating Settlement Issues in Urban Construction Using Hybrid Floating Foundations,” Proceedings of the International Conference on Structural Engineering, vol. 15, no. 1, pp. 67-81, 2020. [4] P. Ghosh and D. Singh, “A Study on Shear Strength Improvement through Hybrid Foundation Systems,” Journal of Soil Mechanics and Geotechnical Engineering, vol. 56, no. 4, pp. 221-239, 2019. [5] American Society of Civil Engineers (ASCE), Guidelines for Foundation Design in Flood-Prone Areas, International Building Code Standards, 2023. [6] Engineering Research Institute, Practical Laboratory Testing for Civil Engineers: Standard Penetration, Consolidation, and Direct Shear Tests for Foundation Analysis, vol. 12, no. 5, pp. 134-148, 2022.

Copyright

Copyright © 2025 Vaishnav V. Khirird, Shailesh B. Varma, Kamlesh R. Wakle, Parth H. Kakade, Prof. A. A. Jagtap. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.