Seismic response of a tall tower on deep soil – A case study

Abstract

The DYNAMIC response of a 100 m tall tower on a deep soil deposit is studied. The considered tower model is investigated for different loading/boundary conditions present at the base. The analyses are carried out using a finite element program SAP 2000. To demonstrate the effect of soil depth on the estimated seismic response of the tower, three different soil depths are considered. In order to study the effect of structural inelasticity and period elongation on the estimated seismic response of the structure, a yield strength ratio, Ry equal to 4 is also considered. The study primarily shows that soil-pile-structure interaction (SPSI) may increase or decrease the base shear and lateral deflection of the structure, in different directions and for different depths of soil strata. The sensitivity of the SPSI effects to the dynamic characteristics of the ground motion and structure has been brought out in the present case study. It is concluded that the effect of soil depth on seismic response of the structure is not monotonic and the role of ductility demand on superstructure in SPSI effects is important.