Forensic Investigations of Concrete Degradation: Case Study of a Hydropower Project

Abstract

This paper focuses on concrete degradation of hydraulic conveyance components of a hydropower project in Uganda that was commissioned in 2019. During a routine outage inspection in 2021, concrete damage was observed in the waterways. The engineering-procure-construct (EPC) contractor was notified to remedy the defects but they declined, claiming that it was normal erosion wear. In order to ascertain the root cause, avert a potential dispute, and apportion liability, a forensic investigation was conducted by the owner. Site inspections, water quality sampling and testing, and concrete core sampling and testing were carried out during the forensic investigation. The findings indicate that the Nile River water is highly aggressive, and the coupled soft water attack and hydraulic erosion-abrasion led to the premature concrete surface degradation. In order to enhance durability and long-term performance of the waterways, a protective surface coating has been recommended. The investigations have been very useful to avert costly and time-consuming disputes between the owner and the contractor because the cause and party responsible for the defects have been identified, and the contractor has agreed to take remedial action in accordance with the contract. The study will be useful for other planned hydropower projects along the Nile River and similar projects globally. The paper reveals the significance of forensic investigations at a hydropower infrastructure project to ascertain the durability of the civil engineering components of the facility, and in turn the overall performance of the infrastructure. The study undertakes a forensic investigation of concrete degradation within hydraulic conveyance components of a recently commissioned hydropower project in Uganda. The findings reveal practical insights for industry practitioners on the key design and construction considerations for hydropower plants or similar water conveyance systems. Key findings from the investigations, as well as durability recommendations for future project waterways, are shared for best industry practice, including adopting a comprehensive durability design and performance-based approach for key infrastructure such as hydropower plants.