Numerical Analysis of the Deflection of a Building on Sandy Clay Soil: Application to a Building in the City of Douala

Abstract

This study presents a numerical analysis of the deflection of a reinforced concrete building founded on sandy clay soil in the city of Douala. To conduct this research, two numerical simulations were performed. The first consisted of a simulation in MATLAB based on mathematical and mechanical models of the building and the soil. The second consisted of a finite element simulation of the building and the soil using COMSOL Multiphysics. The result obtained for the structural deflection after the MATLAB simulation was 0.0026 mm for elastic soil and 4.1 nanometers when the soil plasticity was taken into account. These results show that the rigidity of the structure and the elastoplastic nature of certain sandy clay soils play a very significant role in the stability of the building. Furthermore, the numerical simulation in COMSOL Multiphysics yielded a deflection of 2.2 mm for both elastic and elastoplastic soils. This is explained by the fact that, under steady-state conditions, the structure settles under its self-weight and live load, which, combined with the rigidity of the structure, resists large displacements and considerably reduces deflection. In addition, during the COMSOL simulation, the threshold stresses of the building were 0.16 MPa for elastic soil and 0.20 MPa for elastoplastic soil. These values represent limits beyond which structural deflection could cause damage to the frame.