Defects in structures in Nairobi city: causes and mitigative strategies

Abstract

This research was carried out to determine the causes of defects in structures in Nairobi City and to propose mitigative strategies. The study made use of results of: geotechnical tests, failure investigations, excavation for foundation placement, excavation observation as well as the collective experience of consulting engineers and contactors in the city. The results indicate that the subsoil includes highlyplastic soils, collapsible soils and soft clays of variable thicknesses, red soils containing cavities, weathered and fracture zones of variable profile, expansive weathered tuffs and deep organic fills. The research concluded that each of these soil types has caused distress of varying degree, and as such, an understanding of the critical ground performance is fundamental in a successful construction program.