ASSESSMENT OF THE CAUSES AND IMPACT OF INADEQUATE GEOTECHNICAL INVESTIGATION ON CONSTRUCTION PROJECTS’ PERFORMANCE IN NIGERIA

Abstract

The issue of inadequate geotechnical investigation usually leads to over or under design of structural elements which eventually contributes immensely to project cost overrun and poor performance. This research aims to assess the impact of inadequate geotechnical investigation on construction projects‟ performance which was achieved through the research objectives. The objectives were to examine the difference in awareness level among clients, contractors, and consultants about geotechnical investigation practices in construction projects; to identify the causes of inadequate geotechnical investigation in construction projects; to assess the impact of inadequate geotechnical investigation on construction project performance; and to identify strategies to mitigate the impact of inadequate geotechnical investigation on construction projects. The study adopted quantitative research methods using a structured questionnaire to ascertain the perceptions of respondents on some geotechnical investigation related issues. The survey was conducted with a sample size of 384 with 239 responses (62.2% response rate). The Sampling technique employed was random sampling of professionals in the bracket group of client organizations, contracting firms, and consulting firms. Professionals of interest included Civil Engineer, Geotechnical Engineer, Engineering Geologist, Project Manager, Builder, Architect, Quantity Surveyor, Surveying and Geo-informatics. Data analysis was carried out using a combination of descriptive analysis, rank order, and inferential statistics using Microsoft excel, Statistical Package for the Social Sciences (SPSS), and Statgraphics XVII. The study findings showed that there exists a heterogeneous practice of geotechnical investigation for construction projects among the contracting firms, consulting firms, and client organizations in Nigeria. Findings also showed that the major causes of inadequate geotechnical investigation in building and road projects are sampling technique, equipment, financial constraint, lack of geotechnical expertise, supervision, results presentation, and client awareness. The impact of inadequate geotechnical investigation on cost, schedule, and performance of construction projects amount to overruns and poor performance. The regression model of this study is given as “Y = -.250 + .089X1 - .038X2 + .387X5 + .582X6” for building projects; while in road projects “Y = 1.533 - .055X2 + .106X3 + .486X5 + .139X6”. Additionally, the study rejected the three research hypotheses (null) accepted the alternate hypotheses that “there exists a significant relationship between geotechnical investigation related defects and project cost overrun”, “there exists a significant relationship between geotechnical investigation related defects and project schedule overrun”, “there exists a significant relationship between geotechnical investigation related defects and project performance”. The study recommends adequate sample management, strict adherence to results from geotechnical investigations, and assigning skilled personnel to conduct geotechnical investigation.