Soil-structure interaction analysis using subgrade reaction modulus in raft design

Abstract

This paper presents an analysis of raft foundation behavior and settlement estimation. Soil-structure interaction is incorporated into the studied models through the parameter k (modulus of the subgrade reaction). However, k is limited in applicability due to its lack of intrinsic connection with the soil. The rigidity of the foundation, superstructure, and their projection within the plant, all impact the k parameter, resulting in further constraints. Despite these limitations, integrating k into the analysis can lead to less conservative designs and viable raft foundation solutions that might otherwise be discarded. As a foundational parameter, the modulus of subgrade reaction is evaluated using theoretical expressions, tables, correlations, and empirical studies. This paper aims to present an assessment of the modulus of subgrade reaction and its distribution beneath the raft plate. The evaluation involves theoretical expressions and an indirect method to explore the potential benefits of employing different k values across distinct regions of the plate. The findings reveal a uniform distribution of modulus of subgrade reaction values, leading to the conclusion that incorporating an average of this parameter value in the plate's design analysis can yield satisfactory results. In conclusion, this research contributes to understanding raft foundation behavior in concrete structures by emphasizing the significance of soil-structure interaction through the incorporation of the subgrade reaction parameter k. By addressing the limitations and demonstrating its applicability, this paper encourages a safe, more efficient, and less conservative approach to raft foundation design.