Critical Factors Responsible for Time Overruns in Nigeria Building Construction Industry

Time overruns are major problems facing the Nigerian construction industry. It’s of high concern to those who are involved in the construction industry. This study was carried out to identify the major causes of time overruns in the Nigerian building construction industry, by means of a literature review and a questionnaire survey. A total of twenty (20) time overrun causative factors were obtained from the literature. The questionnaire survey was distributed to randomly selected respondents from a combination of clients, consultants, contractors, site engineers, project managers and sub-contractors. In all, one hundred and forty-one (141) questionnaires were distributed to randomly selected respondents (clients, consultants, contractors, site-engineers, project-managers and sub-contractors), one hundred and thirty-two (132) questionnaires were returned out of which three (3) questionnaires were found incomplete and invalid. Only one hundred and twenty-nine (129) questionnaires were found consistent and valid for use in this research. Relative Importance Index (RII) and Severity Index were used to carry out a ranking analysis. Based on the data received, the five (5) most severe factors influencing project handling overtime in Nigeria construction industries are Inaccurate evaluation of projects time/duration (91.9%), Risk and uncertainty associated with projects (91.6%), Complexity of works (87.6%), Weak regulation and control (86.8%) and Lack of financial power with severity (86.3%).

Assessment of Risk and Uncertainty Factors Inherent in Nigerian Highway Project Using Analytical Hierarchical Process

The study presents a framework through which risk and uncertainties in Nigeria highway projects can be appraised using the analytical hierarchical process model. Pairwise comparison matrix was performed on eleven (11) risk and uncertainty factors that affect highway project performance through a questionnaire survey conducted among two hundred and four (204) respondents, which involved various stakeholders in the highway construction industry using Saaty’s AHP rating scale. The relative weights (significance/impact level) of each of the highway risk factors were estimated during the AHP model development. The results in descending order of risk factors priorities are Standard & Regulations (S&R), Construction (C), Project Staff (PS), Project Sponsor (PSp), Design (D), Project Finance (PF), Economic (E), Equipment (EQ), Environmental & Geotechnical (En&G), Site Location (SL) and Subcontractor (S) with impact levels of 16.6%, 14.2%, 13.9%, 13%, 12.7%, 12.2%, 10.8%, 9.8%, 6.2%, 4.2%, and 3.8% respectively. The model was validated using the statistical consistency test, with the model showing a consistency ratio equal to 0.1. The model was then applied to five (5) highway construction projects which had been constructed to predict the ones with the most and least risks. The result was in tandem with that which was given by the project managers from experiences on the project. This study showed that the Analytical Hierarchical Process (AHP) decision support model can effectively be used for risk assessment and prioritization of highway construction projects for efficient resource utilization in Nigeria.

Development of a Cassava Harvester

Cassava is a major source of food and raw material for domestic and industrial uses in Nigeria. Consequently, the technologies involved in its cultivation from planting to harvesting require proper development. This paper reports the development of a labour-saving technology for harvesting cassava using standard procedures for designing soil engaging implements. Locally available materials were also used in the fabrication of the harvester. Results of trial tests indicate a digging efficiency of 58.9%, fuel consumption of 16 l/ha, field capacity of 0.11 ha/hr, field efficiency of 67.9% and root damage of 43.03%. The total cost of fabricating the machine was 184,000 naira only. Further tests under various soil and operational conditions for improvement and optimization were recommended for the purpose of patenting for commercialization.