DEVELOPMENT OF MULTI-OBJECTIVES OPTIMIZATION FOR BUILDING CONSTRUCTION INDUSTRY MANAGEMENT IN NIGERIA

Abstract

This research is aimed at developing Cost-Time-Quality Optimization Algorithms (CTQOA) for efficient and effective management of projects in Nigeria. The work considered all the influencing project performance factors (constraints) and categorized them into three (3) main groups: cost, time and quality. Among other cities that met the conditions set for the study, three cities (Abuja, Lagos and Portharcourt) each from three different states in Nigeria were selected for the study. These three selected cities are known for their rapid development and their high rate of heavy construction projects among others cities in Nigeria. The targeted respondents were 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. out of which only one hundred and twenty nine (129) questionnaires were found consistent and valid for use in this research. Experimental field data was collected from three heavy building construction sites (one site each from each city under study). Relative Importance Index (RII) and Severity Index were used to carry out ranking analysis. Six (6) most severe factors of construction cost overrun were identified as: risk and uncertainty related factors (89.5%); lack of financial power by clients (88.5%); weak regulation and control (88.2%); project fraud and corruption (82.6%); variation of prices (81.3%) and indiscriminate change in design/works (80.1%). In addition, the results also showed that five (5) most severe factors affecting project duration management in Nigeria includes: inaccurate estimation 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 by clients (86.3%). Furthermore, eight (8) most severe factors affecting quality were: construction mistakes (89.4%); use of inexperienced labours (88.4%); poor checking and inspection (87.5%); poor motivation system (86.6%); poor management commitment and leadership styles (85.7%); unavailability of good quality construction materials (85.1%); limitation of finance and budget (85.0%); and inadequate timely supervision (84.5%). Statistical Package for Social Sciences (SPSS) software, was thereafter used to carry out multiple regression model between cost, time and quality. Regression Square (R2) results showed that a very strong inter-dependent relationship existed between cost, time and quality with value of 0.945, 0.941 and 0.888 respectively. Multi-objective optimization algorithms were formulated and tested using performance index method. Results showed increase in variance values which indicated that the developed algorithms from this research were valid and satisfactory. This imply that cost, time and quality can be effectively and efficiently managed on a building construction site, using the developed cost-time-quality multi-objective algorithms from this research