Restoration of Coker Structures

Coker structure is a heavy industrial reinforced concrete construction in a refinery that supports a delayed coking unit, consisting of multiple coke drums, on an elevated platform. The process temperatures inside a coke drum can reach up to 480 °C (900 °F) and thus subject the supporting concrete structure to extreme thermal gradients. Due to these high temperatures in conjunction with mechanical stresses, the areas of concrete surrounding the coke drums deteriorate over a period of time and in most cases before the lifetime of the concrete structure. The deteriorated reinforced concrete elements needs to be addressed before they lose structural capacity which may lead to a structural failure. Thus, it is important to develop an effective repair strategy for the restoration of the Coker structures giving at most importance to the safety during construction and reliability of repairs to extend the lifetime of the structure. A Coke drum can reach up to a weight of 2.7×10⁶ kg (6000 kips) under its full operating condition. Considering the size of these drums, it is very critical to design a phased repair solution for the repair of Coker structures when they are deteriorated over the course of their service life. A phased repair solution is developed by analyzing the structure by redistribution of drum operational weight and wind force on the drum on to the structure’s non-critical members which are repaired in the subsequent phases of construction. The construction of the repair and the effectiveness of the repair to develop the structure’s original strength depends on the ability if the repair to transfer the planar stresses between the existing concrete and the new repair material. A repair mechanism to transfer these stresses will be discussed as a part of the best repair approach for concrete sections.