Soil-structure interaction influence on shallow foundations design on rocky mass in a reinforced concrete building

Soil-structure interaction (SSI) has mechanisms that allow analyzing the structural performance of a building, considering its foundation, its superstructure and as singularities of the terrain on which it will be built as a single system. The present study aims to carry out the redesign foundations project of a reinforced concrete building (tower "A"), consisting of 22 pillars, with isolated and associated footings foundations on a rock mass of granitic composition and RQD predominantly higher than 75%, considering this interaction, based on the redistribution of efforts between the pillars of the structure, verifying its influence on the geometry and consumption of materials in the design of its foundation elements. After redesign, the results obtained revealed that there was no significant change in foundation geometry, as well as in the consumption of concrete comparing the projects with and without SSI. For steel consumption, the results showed an increase in the steel area of the associated footings SPA-07/13 and SPA-10/16 and the isolated footings SPA-15 and SPA-20; while the SPA-01 and SPA-21 isolated footings obtained a certain decrease in this material. It is concluded that, for this project, the soil-structure interaction did not have a significant influence on the observed points, due to the low efforts redistribution on the analyzed pillars, which was reflected in the maintenance of dimensions and quantity of materials in almost all of the foundation elements studied.