Investigation of Steel Chimney Retrofitted with Nanocoating Under Earthquake Excitation Using FEM

The aim of this research is to determine the effect of nanocoating retrofitting on the dynamic responses of industrial steel chimneys. A 20 m high industrial steel chimney was selected for nanocoating retrofitting. First, a three-dimensional finite element model of the chimney was created, and modal analysis was performed in SAP2000 software, and frequency values and mode shapes were obtained. Later, linear analyses of the chimney were made using the 1995 Kobe earthquake ground motion recording. Then, the outer surface of the chimney was retrofitted with a 1 mm MgO nanocoating, and dynamic analyses were made. Finally, the chimney’s dynamic responses before and after the MgO retrofit, such as minimum–maximum von Mises stresses and displacements, were compared. At the end of the study, it was observed that the displacements along the chimney height, especially maximum displacements, decreased from 150 mm to 140 mm, and the minimum von Mises stress at the bottom of the chimney decreased from 37.20 kPa to 30.19 kPa, and the maximum von Mises stress from 1519.27 kPa to 1332.33 kPa stresses in the analyses results. The decrease in frequency values revealed that MgO nanocoating had a positive effect on the stiffness of the chimney. It can be understood from this study that nanocoatings will be very useful in retrofitting industrial steel chimneys and have an effect on dynamic parameters.