Evaluation of structural defects and the dynamic of stress and strain on a building along Oluwole Area, Southwestern Nigeria

Abstract

This research was carried out within the Basement Complex terrain along Oluwole, off Akure High School, Akure, Ondo State, Nigeria, with the aim to ascertain the reasons for the major cracks and sign of apparent failures observed in a building few years after its construction and usage. The geophysical investigation involved two electrical resistivity techniques; Vertical Electrical Sounding (VES) using the Schlumberger configuration and 2-D electrical imaging using Dipole-dipole electrode configuration. Three traverses were established E–W direction cutting across geologic strike with a distance of 100 m and of varying inter-traverse spacing. Six (6) VES stations were occupied covering the entire study area for layer stratification and geoelectric parameters. The results were qualitatively and quantitatively interpreted and are presented as sounding curves and geoelectric sections. The 2-D imaging gave information on the subsurface characteristic in the area with generally low apparent resistivity indicating low competence material. The results obtained from the VES delineated four to five geoelectric units which comprise of the topsoil, moderately clayey sand layer, the partially weathered layer, resistive partially fractured basement and fresh basement. The results from the VES were used to determine the second order parameters. The entire results correlate well with one another showing that all the techniques used were complemented. This study has further justified the inevitability of geophysical site investigation for necessary foundation evaluation before embarking on any construction of any kind.