Engineering Significance of Annular Raft Foundations over Solid Raft FoundationsJ

Abstract

Abstract: Raft foundations play a pivotal role in distributing structural loads to the underlying soil, thereby ensuring the stability and integrity of various civil engineering structures. The choice between different types of raft foundations, such as solid and annular rafts, significantly impacts the overall performance and durability of a structure. This paper explores the engineering significance of annular raft foundations in comparison to solid raft foundations. The traditional solid raft foundation offers uniform load distribution and settlement control; however, it often encounters challenges when dealing with non-uniform soil profiles, differential settlements, and expansive soils. Annular raft foundations, a relatively innovative approach, address these challenges by featuring a central void within the raft. This void introduces a controlled differential settlement mechanism, enabling the foundation to accommodate non-uniform soil conditions effectively. Moreover, annular rafts offer improved structural performance in regions prone to ground movements, as the central void allows the foundation to adjust to soil displacements more flexibly than a solid raft. The engineering significance of annular rafts extends to their enhanced loadbearing capacity and reduction in material usage compared to solid rafts. The design of annular rafts takes advantage of the arching effect within the void, which enables the foundation to support heavier loads while minimizing the amount of concrete and reinforcement required. This not only contributes to cost savings but also aligns with sustainable construction practices by reducing the environmental impact associated with excessive material consumption.