Project Type: Evaluation, Design, Construction Administration
The Vital Structure:
Campus Cooling Tower Basin Slab – Concrete Repairs and Waterproofing System Replacement
Issue
Vital Structures was retained to provide waterproofing and concrete restoration engineering services for the basin slab below two (2) cooling towers, located atop the 5-story building roof, serving a University campus in Cambridge, MA. The existing basin slab, which also serves as the building roof, was previously coated with a polyurethane coating which had exceeded its service-life. The coating is exposed to treated effluent water from the campus cooling tower system.
Diagnosis
The basin slab concrete coating is exposed chemical, impact, thermal shock and wear-and-tear from operations related to the cooling towers. In addition to the concrete waterproof coatings, corrosion mitigation, concrete repairs and miscellaneous metals repairs were required, including a new OSHA-compliant access ladder, bar grating and stair walkover platform.
Solution
Vital Structures performed a comprehensive evaluation with exploratory test cuts and petrographic analysis of the concrete basin slab. A chemical analysis of the cooling tower water was provided by the Owner and submitted to the waterproofing system manufacturer to assess compatibility with the coating system. A hybrid polyurea-polyurethane coating system was selected for the project based on cure time, chemical resistance and durability to impact and thermal shock.
Result
The Owner required that the project be completed during the 2023 Winter season during a short window while the Cooling Towers were not operational. The rapid cure and short turnaround time of the polyurea hybrid coating system provided a major benefit to the client as temporary protection and heating of the area was required. New pipe supports, piping and electrical conduits were able to be installed shortly after the coating application was completed, meeting the Owner’s schedule requirements. The project also provided hot-dip galvanized access ladders and stairs to replace the corroded components to maintain safety of the systems.
