The possibility to consider the effect of relative displacements between the soil and the structure is in line with the “displacement based design philosophy of most modern seismic design codes. Beneficial effect of soil structure interaction (SSI) in the design phase of earthquake resistant structures is a main issue in modern earthquake engineering. Nevertheless special care is necessary to quantify to which extent the beneficial reduction of forces in the structure is accompanied with undesired residual displacements which might affect structure serviceability or structural integrity. Commonly used SSI analysis, based on use of direct methods (e.g. finite elements), require the choice of a wide range of parameters and a relatively long calculation time. It is therefore of practical relevance to speed up the calculation time and to simplify the choice of the input parameters. Even more in the preliminary design phase when intensive parametric studies might be necessary. In order to achieve such goals recent solution strategies based on hybrid method approach replace the system soil-foundation with non linear macroelements and calculation time is drastically reduced. The presentation will describe a model of 2D dynamic macroelement for seismic behavior of shallow foundations, its numerical implementation and how convergence and final results are improved.     «

The possibility to consider the effect of relative displacements between the soil and the structure is in line with the “displacement based design philosophy of most modern seismic design codes. Beneficial effect of soil structure interaction (SSI) in the design phase of earthquake resistant structures is a main issue in modern earthquake engineering. Nevertheless special care is necessary to quantify to which extent the beneficial reduction of forces in the structure is accompanied with undesir...     »