Geotechnical and Geophysical Investigation into the Causes of Cracks in Building: Case Study of Some Buildings in School of Engineering Kogi State Polytechnic, Itakpe Campus, Kogi State North Central Nigeria
Publication Date: 29/11/2018
Author(s): Onsachi J. M, H. M Yakubu, Shaibu M. M.
Volume/Issue: Volume 1 , Issue 1 (2018)
Abstract:
The aim of study is to investigate the major cause of cracks observed in majority of the buildings in school of engineering Itakpe campus of Kogi State Polytechnic, Kogi state. To achieve this aim, both geotechnical and geophysical approaches were adopted to study the soil properties and subsurface formations respectively. Soil samples were collected around the area of the affected building for laboratory study. The properties determined were natural moisture content, particle size distribution, Atterberg limits, proctor compaction, and specific gravity. The results of the tests show that the site is dominated with poorly graded soil with specific gravity (2.2 - 2.7), liquid limit (25.8 % - 39.0 %), plastic limit (18.8 % - 35.1 %), Natural moisture content (3.89 % - 27.91 %) and maximum dry Density (620 kg/m3 - 825kg/m3). Geophysical survey involving the electrical resistivity method utilizing the Vertical Electrical Sounding (VES) techniques conducted around the crack walls of some building with the aim of studying the causes of crack in the walls and characterizing the soil conditions of the area. A total of 8 Vertical Electrical Sounding (VES) stations were occupied using Schlumberger Configuration with AB/2 varying from 1 to 65 m. Three geoelectric sequences were delineated within the study area. These include the topsoil, weathered layer, and fresh basement. Results identified differential settlement resulting from incompetent subsoil materials are the possible causes of the failure.
