Anchor Bolt Failures in Coke Drums

Anchor bolt failures that are commonly experienced by coke drums typically show signs of axial and/or shear overload. Temperature measurements and thermographic images have demonstrated that side-to-side temperature differences in coke drums can be more than 400 degrees Fahrenheit. In this paper, finite element models are used to examine the displacement of skirt base plates. Various combinations of circumferential thermal gradients, support deck slopes, and friction coefficients between drums and support structures are used. The study shows that observed thermal gradients can result in significant longitudinal, circumferential, and radial displacements and explains observed overload failures of anchor bolts. In addition, the study demonstrates the roles of deck slope and friction coefficient on base plate displacements.