Hindle Mason Projects, a leading structural rehabilitation and corrosive/erosive protection specialist, is forging ahead with the extensive civil-engineering rehabilitation and repairs to the natural draft cooling towers at a petrochemicals plant.
Hindle Mason Projects commenced working on the project in 2018 and has since completed three towers, a significant undertaking that entailed working in up to 14 different areas at a single tower. The company is now close to finalising work on the fourth structure by August 2023. This aspect of the work scope has involved working in five different areas.
Through extensive planning and careful coordination of the work in each area, the company has been able to bring the construction schedule forward. Hindle Mason Projects has always delivered quality workmanship on time and within budget for this client. This was among the reasons that the company was appointed as the preferred specialist civil engineering repair and rehabilitation contractor for this project. The company is completing this work while working alongside the principal contractor, which is involved in other aspects of the natural draft cooling tower refurbishment programme.
Notably, the repairs are being undertaken to the natural draft cooling towers while they remain functional to avoid disrupting operations in the industrial complex.
Therefore, a unique method of accessing the many work areas, including the deteriorated reinforced concrete columns and beams, inside the cooling tower at distribution level had to be developed. The distribution level is located at the bottom of the natural draft cooling towers at a height of 13,5m. It collects and stores the cooled water that is pumped back to the industrial complex.
Enver Candasamy, Hindle Mason Projects’ Construction Manager, says that the repairs to the concrete columns and beams are, thus, being undertaken from floating scaffolding platforms.
“This is the first time that repairs are being undertaken to operational natural draft cooling towers and from floating scaffoldings. The pontoons, comprising a cluster of plaster containers, each support large towers of scaffolding that weigh about 150t. This unique access solution was designed and manufactured specifically for this application, and it is also the first time that our teams have undertaken refurbishment and repairs in this manner,” Candasamy says.
Working closely with the consulting engineering firm, Hindle Mason Projects has devised many different civil engineering repair and rehabilitation solutions for this project. They are based on the company’s deep understanding of the causes of the deterioration of concrete structures.
The natural draft cooling towers, each about 190m in height, have been operating since the late 1970s and have, thus, demonstrated many ageing effects. This includes scaling due to freeze/thaw cycles. The steel reinforcement has also corroded due to carbonation, weakening and cracking the concrete over time. Cleaned flue-gas injection has also had a deleterious effect on the concrete of these structures over extended periods.
Natural draft cooling towers are very costly concrete structures to construct so it is imperative to preserve them. Hindle Mason Project’s state-of-the-art civil engineering repair and rehabilitation solutions will prolong the lives of these assets by more than 20 years. Combined with the refurbishments undertaken by the principal contractor, the overall efficiencies of the towers will also be significantly raised.
The company’s teams remove the damaged concrete before visually inspecting these areas to define the scope of work for each element. They then execute the repairs to the internal structure of the concrete before reinstating it to its original condition. Thereafter, the various reinforced concrete elements receive a waterproofing coating to complete the process. As part of the work scope, Hindle Mason Projects also replaced structural steel elements in the natural draft cooling towers with corbel brackets and structural steel elements.
Working in operational areas can be dangerous. Therefore, once again, Hindle Mason Projects’ team is working to very strict health and safety protocol. There has, thus, not been a single serious incident on site since it mobilised to site to start working on the project five years ago.
The Hindle Mason Projects team involved in this large-scale undertaking consist of 74 employees. Ben du Preez serves as Project Manager; Enver Candasamy and Lee McCormack as Construction Managers; and Justin Maans as Lead SHE Officer. Du Preez attributes the successful outcome thus far to excellent team dynamics between Hindle Mason Projects, the principal contractor, as well as the client body.
