Calculations of internal forces and rational reinforcement of raft foundation resting on Kerr-equivalent Pasternak ground

Abstract

Currently, the internal forces of raft foundations are generally calculated by the rigid strip method without considering the soil-structure interaction. To overcome the problem, the elastic foundation plate method arose, but most applications are based on the single-parameter Winkler foundation model. Recently, Worku and Seid proposed a Kerr-equivalent Pasternak two-parameter foundation model that belongs to the continuum model and possesses the same precision as the solid finite-element model. While the authors found that their two parameters formulations are inacurrate. For that, two calibration factors were introduced. Based on the soil’s deformation modulus determined by the plate load test, the approach to accurately determining the two parameters was obtained. The finite-difference method was established, and the corresponding program was developed by using Matlab. The application of the Pasternak model in the design calculation of a practical raft foundation was given for the first time. The results agreed well with those of the finite-element method, which validated the reliability. The rebar configuration according to the internal forces computed by the proposed method is more reliable than that of the existing method. As a result, the proposed method can prominently enhance the reliability in computing the internal forces and reinforcement of raft foundations.