Professional Assessment of Geotechnical Practices in Building Foundation Design in Expanding Cities of North West Nigeria

Foundation failures in rapidly expanding cities of North West Nigeria, including Kano, Sokoto, and Kaduna, are frequently attributable to inadequate geotechnical investigation, and professional assessment of current geotechnical practices provides evidence for improved regulatory oversight. This study assessed geotechnical investigation practices in foundation design for residential, commercial, and institutional building projects across the three cities, based on a review of 60 geotechnical investigation reports and structured interviews with 45 geotechnical engineers, civil engineers, and building control officers. Report quality was evaluated against BS EN ISO 22476 standards for geotechnical investigation. Investigation frequency, test types, laboratory analyses, and recommendation completeness were assessed. Results showed that geotechnical investigation was conducted in only 38% of reviewed projects. Among projects with investigations, 62% relied solely on trial pit inspection without laboratory testing of soil samples. In-situ testing such as standard penetration testing was conducted in only 23% of cases. Settlement calculations were provided in fewer than 20% of reports. Borehole depths were inadequate (below design requirements) in 44% of reports. Building control officers reported that geotechnical investigation was not mandatorily enforced in any of the three cities for residential projects below four storeys. The study concludes that geotechnical investigation practices are seriously deficient across North West Nigerian expanding cities, and recommends mandatory geotechnical investigation for all multi-storey and commercial projects.

Keywords: geotechnical investigation, foundation design, North West Nigeria, soil investigation, building control