Evaluation of Settlement and Bearing Capacity of Three Selected Buildings in Ibeju Lekki, Lagos

Abstract

This study assessed the geotechnical properties of soils at three locations with distressed buildings in Ibeju-Lekki, Lagos State, Nigeria. The aim was to identify possible geotechnical causes of structural impairments and ongoing deterioration, which led to occupant evacuation. Three buildings, labelled A, B, and C, were analyzed. Disturbed soil samples were collected from fourcorners at foundation depths to evaluate soil properties and their potential effects on structural performance. Index properties, including grain size distribution, moisture content, and specific gravity, were determined for soil classification. A triaxial test was conducted to determine cohesion and internal friction angles, while Terzaghi’s equations were used to estimate bearing capacities.Consolidation tests were performed to compute both immediate and final settlements, providing insights into soil behavior under load. Results showed moisture content ranging from 2.02% to 16.04%, with the lowest in sample C4 (2.02%) and the highest in B4 (16.04%). Specific gravity values ranged between 2.55 and 2.65. Soil classifications were A3 (AASHTO) and SP (USCS),indicating poorly graded sands. Mean bearing capacities for buildings A, B, and C were 102.05 kN/m², 90.54 kN/m², and 96.25 kN/m², with standard deviations of 41.35 kN/m², 26.65 kN/m², and 48.39 kN/m², respectively. Final settlements averaged 0.3 cm, 0.24 cm, and 0.34 cm, with standard deviations of 0.09 cm, 0.06 cm, and 0.2 cm. Building C exhibited higher variability insettlement and bearing capacity, suggesting greater susceptibility to further structural distress. A correlation of -0.43 between bearing capacity and settlement confirmed that lower capacities correspond to increased settlements. The study emphasizes the importance of proper soil investigations and strict adherence to geotechnical recommendations during construction to prevent failures.