DDCC Gee Building Column Repairs

The concrete encasing the exterior steel columns and girders over the entrance to the Gee Building at Davidson-Davie Community College was significantly cracked, posing an overhead fall hazard. Atlas Engineering was retained to perform a structural evaluation and subsequent structural repair design. Our inspection revealed large sections of cracked and loose concrete, prompting Atlas to quickly provide the College with an overhead protection plan.
Thorough fieldwork, including selective concrete demolition to assess the condition of the embedded steel, and concrete testing to evaluate the risk of corrosion based on chloride content and possible carbonation was conducted by professional engineers. Fieldwork revealed surface corrosion and some section loss to embedded steel members, likely from freeze-thaw cycles.
Atlas expedited design of structural repairs to address the deteriorated areas, with a specific focus of beginning the repairs in the narrow window of winter break.
Initial repairs involved removing all cracked and loose concrete, cleaning and removing corrosion, and coating steel with zin-rich paint to prevent future corrosion. Hairline cracks in otherwise sound concrete were injected with epoxy, and all exposed concrete faces were coated with a vapor-permeable coating to mitigate future water intrusion.
As the existing concrete was removed, more significant corrosion was uncovered. Atlas Engineering quickly assessed the unforeseen damage and provided additional repair design to ensure structural integrity and reduce future corrosion. They recommended reinforcing the steel members with steel plates and WT members and installing passive zinc anodes and tie wires to the steel members before placing new concrete.