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30 DECEMBER 2016 MATERIALS PERFORMANCE NACE INTERNATIONAL: VOL. 55, NO. 12 CATHODIC PROTECTION U Cathodic protection (CP) of under- ground steel structures is a mature technology for structures with simple geometries, such as pipelines and storage tanks. Nevertheless, this technology is not well-adapted to structures with irregular geometries, where application of conventional anode bed designs are formidable due to the interplay of geometrical and electrochemical effects. A simu- lation-based approach is presented to design optimized galvanic anode beds for complex structures in soil environments by considering exact geometry and factual design data. To showcase some unique capabilities of the design methodology, CP sys- tem designs for grillage-type founda- tions for power transmission struc- tures are considered. Underground corrosion of structures supporting power transmission and distri- bution (T&D;) lines is the primary cause of in-service equipment degradation. Each year, utility companies allocate increased corrosion mitigation budgets to refurbish a large population of aging and corroded str u cture s. Ac c ordin g ly, ef fe ctive and economically feasible corrosion mitigation techniques, such as cathodic protection (CP) systems specifically designed for T&D; structures, are in great demand. Galvanic Cathodic Protection for Power Transmission Tower Grillage Foundations Peyman Taheri, Matergenics Engineering, Vancouver, British Columbia, Canada m ehrooz z amanzadeh, F na C e , Exova Group, Pittsburgh, Pennsylvania Widely used conventional CP design methods are based mainly on empirical for- mul a s an d d e si g n er e xp eri en c e. Su ch design methods, although very useful, were primarily developed for piping systems and are not optimal for structures with more complex configurations. They fail to incor- porate all design factors and often require the use of relatively large safety factors. To address this issue, an electrochemical sim- ulation tool was developed for designing efficient CP systems for buried compo- nents of transmission structures. Grillage- type foundations were selected to highlight some capabilities of the proposed approach because these types of foundations are common in transmission structures, and their geometrical irregularities (e.g., edges, holes, bends, and joints) pose a recognized CP design challenge that requires further investigations. Steel Grillage Foundations Transmission tower foundations are required to stabilize the towers by transfer- ring the structural loads to the under - g r o u n d e nv i r o n m e n t . T h e y m u s t b e designed to resist movements such as set- tlement, uplift, and lateral displacement. 1 Among different types of foundations, steel grillage foundations are the preferred choice for four-legged lattice towers when footing conditions allow their application. Grillage foundations include a horizontal grillage base plate constructed from struc- tural st e el (u sual ly galvani z ed an g l e s, beams, and channels), and some vertical