Charlotte, NC

ZAPATA was contracted by Southern Environmental Inc. to perform a design/build project to replace the existing fly ash housekeeping pad for electrostatic precipitators (ESP) 3 and 4 at Duke Energy’s Marshall Steam Station. The original concrete pad was poured several months earlier by a second tier contractor. The pad experienced drainage problems. Water drained into an electrical cable trench or ponded on the pad until it evaporated. The scope of work included evaluation of the concrete drainage conditions and design of a solution suitable to Southern Environmental and Duke Energy’s Marshall Steam Station personnel. A laser scan survey was conducted and drawings created showing contour elevations of the pad surface to ¼” intervals. ZAPATA recommended 13,000 square feet of the southern portion of the existing pad be removed and replaced with a new drainage configuration while matching the existing elevations of the pad where equipment remained. ZAPATA conducted geotechnical investigations to ensure the subsurface soil was properly compacted. 500 tons of aggregate base courses was added and graded by a laser guided motor grader to proposed subgrade elevations. 262 cubic yards of concrete were placed and finished in one continuous pour. The new pad included roadway turndown sections of the east and west sides. Adjacent yard areas were graded to ensure proper runoff into existing storm drains. The project was fast tracked and completed in 14 days.

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