Dynamic Analysis of Structures Including Soil-Structure Interaction Using Ritz Method in Frequency Domain

In dynamic analysis of many lifeline structures, the soil-structure interaction plays a very important role. It is well known that, the soil must be dealt as an infinite domain to include properly the effect of this interaction into analysis. Apart from modal analysis, one can reduce the number of final equations by assuming the deformed shape of the structure as a linear combination of independent Ritz vectors. The efficiency of this method relies heavily on the vectors selected, especially when an infinite domain is included in the analysis. In this paper, a new set of Ritz vectors is proposed. It is primarily proved that these vectors are linearly independent. Subsequently, various two and three-dimensional concrete dam-foundation systems are analyzed based on the proposed method. In each case, the results are compared with the ones obtained based on usual Ritz and modal analysis methods. It is finally concluded that the proposed method is very effective and efficient method for dynamic analysis of structures including soil-structure interaction.