OBSERVATION AND NUMERICAL-ANALYSIS OF SOIL-STRUCTURE INTERACTION OF A REINFORCED-CONCRETE TOWER

A vast amount of earthquake response records of an observation tower are used together with microtremor data to investigate various aspects of the dynamic behaviour of the soil-structure system. It is found that separation of the soil from the structure occurs under large dynamic loads, leading to changes in the predominant frequency of the system. As a result of the decreasing of the soil support at the side walls of the foundation, the stress caused by the structural weight on the bottom soil increases during earthquakes, With regard to its practical applicability, a linear sway-rocking model is applied for numerical modelling of the soil-structure system. Alterations in the soil support as a result of soil non-linearity and separation of the structure from the soil are investigated by comparing recorded and simulated structural response. The influence of each of these factors on the softening of the soil support is distinctly assessed. An empirical relationship between the peak ground velocity and the soil constants for earthquake excitations of different magnitude is presented.