A process column is a tall cylindrical tower and is widely used in process industries. Structural integrity of a process column was assessed for present seismic requirements and found that the anchors are not meeting the codal requirements. It is proposed to qualify by strengthening the foundation and increasing the number of anchor bolts. However, it requires digging around the existing foundation, adding extra anchors etc. It was found that due to space constraints this scheme is not suitable. Hence, it is found that retrofitting using energy dissipating devices may be the suitable option for seismic requalification of process columns. Various energy absorbing devices such as tuned mass damper, tuned liquid damper and lead extrusion dampers may be used for response reduction. For the present case, suitability of Lead Extrusion Dampers (LED) to reduce the seismic response of process column is studied. The LED absorbs vibration energy by plastic deformation of lead. Seismic response reduction in process column is studied by providing LEDs at suitable elevation. Iterative Response Spectrum method is used to evaluate the response of the process column with LEDs. In the present paper, details of design of LED, analysis of process column supported on LED and its effectiveness for response reduction are discussed.

Keywords: Lead Extrusion Damper (LED), Response reduction, Iterative respone spectrum method.