Soil-structure interaction analysis in reinforced concrete structures on footing foundation

Soil-structure interaction (SSI) evaluates how soil or rock deformability imposes on the structure a different load path in a hypothesis of fixed supports, altering the loads acting on the structural elements and the ground. This paper discusses the results of the SSI effects in two buildings with a reinforced concrete structure and shallow foundations in a rock mass. The settlements were monitored by field instrumentation in five stages of their construction, making it possible to estimate through interpolation curves the settlements values of some points. The numerical modeling and structural analysis of the buildings were obtained for two different cases of soil-structure interaction. The structure was considered having fixed supports (non-displaceable) and displaceable supports (with stiffness spring coefficients K). The results reveals the occurrence of SSI effects, with a load redistribution between the columns that occurred differently for the different construction stages. Structural modeling proved to be quite representative, pointing to higher vertical load values than the average values present in building edge zones, which contradicts the conventional idea that central columns are more loaded than the edge columns. The soil-structure interaction analyses resulted in different behaviors regarding both towers; pointing out that low settlements and building symmetry in plan minimize the effects of interaction, with no tendency of load redistribution between columns as the structure rigidity increases, as construction development.