Effect of different foundation and soil properties on building structural system

The effect of foundation behavior is neglected by accepting the foundation as infinitely rigid at the base of the buildings as it is practical in seismic design and performance evaluation. Studies in the literature shows that the deformations and rotations in the foundation can significantly change the behavior of the structure. In order to examine this change, a study based on reinforced concrete buildings has been planned. 25 different types of buildings, which have different foundation types and dimensions reflecting the characteristic features of existing reinforced concrete buildings in our country and built on soils with different stiffness are taken into account. Buildings are designed on the basis of TS500 and TBDY2018 and three-dimensional models are prepared using the SAP2000 program. The behavior of infill walls is defined by equivalent compression struts. All models are evaluated using nonlinear static analysis. The differences of the horizontal strength, period and displacement demand values of the buildings according to the fixed base assumption is examined and the damage situation is evaluated. According to the results of the analysis, an increase of approximately 15% is observed in the building period and displacement demands, even in the most ideal situation. It is possible for this increase to reach 82% in unfavorable conditions in terms of foundation dimensions and soil stiffness. The effect of different foundation conditions on the damage distribution in the structure is generally below 10%. The effect on the horizontal strength is less than 2% for the foundation dimensions in accordance with the seismic code.