OBSERVATION AND NUMERICAL-ANALYSIS OF SOIL-STRUCTURE INTERACTION OF AREINFORCED-CONCRETE TOWER

A vast amount of earthquake response records of an observation tower a re used together with microtremor data to investigate various aspects of the dynamic behaviour of the soil-structure system. It is found tha t 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 o f the foundation, the stress caused by the structural weight on the bo ttom soil increases during earthquakes, With regard to its practical a pplicability, a linear sway-rocking model is applied for numerical mod elling of the soil-structure system. Alterations in the soil support a s a result of soil non-linearity and separation of the structure from the soil are investigated by comparing recorded and simulated structur al response. The influence of each of these factors on the softening o f the soil support is distinctly assessed. An empirical relationship b etween the peak ground velocity and the soil constants for earthquake excitations of different magnitude is presented.