Structural Performance of Reinforced Concrete Water Towers in Northern Nigeria: A Case Study in Katsina State

Elevated reinforced concrete water towers are critical components of water supply infrastructure across northern Nigeria, particularly in Katsina State in the North West geopolitical zone, where ground-level supply pressure is insufficient for distribution to elevated communities. This study assesses the structural performance of eight elevated water towers in Katsina, Daura, and Dutsin-Ma, examining the condition of support columns, foundation systems, tank walls, and base ring beams. Inspections were conducted following a modified condition grading system adapted from AWWA D100 and the World Bank Infrastructure Management Guidelines. Non-destructive testing including rebound hammer and ultrasonic pulse velocity measurements was performed on column shafts and tank walls to estimate in-situ concrete quality. Water tightness was evaluated through observation during and after a controlled fill test. Findings indicate that five of the eight towers had column concrete that failed to meet the minimum rebound hammer classification for the C20 grade assumed in their original designs. Corrosion staining and spalling at the column-tank junction were identified in six towers, with two exhibiting tensile cracks in the ring beam at the tank base indicating potential overturning moment resistance deficiency. One tower, estimated at over 30 years in service, was classified as requiring immediate decommissioning due to severe section loss in two support columns. The study recommends a national database for water tower structural health, adoption of routine 5-year structural inspections, and the application of fibre-reinforced polymer wrapping for column rehabilitation where corrosion damage is moderate. Keywords: water towers, structural performance, Katsina State, non-destructive testing, infrastructure.