Effect of Soil Damping in Soil-Structure Interaction on The Seismic Response of Reinforced Concrete Elements.

Abstract

The main objective of this research is to contribute to a quantification of the effect of soil damping within the soil-structure interaction framework on the seismic design of reinforced concrete structures. For this purpose, a model that compiles all factors to be considered in a soil–structure interaction problem was developed. The physical model of the structure is based on a slender reinforced concrete building with underground stories, lying on dense sand in a case and on loose sand in another. This model is subjected to earthquake input signal and modelled using Plaxis finite element analysis software. The HS-Small constitutive soil model in Plaxis was adopted to represent the soil’s hardening behavior when subjected to earthquakes. Hysteretic, Rayleigh, radiation and numerical damping were introduced into the numerical model and their influence was analyzed. The seismic load was incorporated by the ground acceleration record of Loma Prieta earthquake and simulated in Plaxis in terms of horizontal prescribed displacements. The results obtained lead to a direct assessment of the importance of including damping and how it alters the seismic design of reinforced concrete buildings. These results can be illustrated in terms of the effect damping has on the lateral displacements and design base shear of the superstructures and the lateral earth pressure on the retaining walls as well as the horizontal pressures of the soil elements. In addition, this research item provides the calculation method required to accurately incorporate damping coefficients in numerical modelling.