The application of six sigma - supported expert system in construction projects

Abstract

Certain methods and techniques are usually applied in the construction industry to ensure a level of quality necessary to make a project proportionally capable of meeting the terms and requirements set in its contract. The research was conducted on Al-Rumaitha residential project where lack of quality was detected in a number of concrete samples. Actually low-quality samples picked up indicated that low-quality concrete was casted onto the third-story roofs of buildings A25 and A26 and second-story roofs buildings A27 – A 33. The same holds true to the samples taken from the upper roofs of the buildings A15, A16 and A19. This is a research that aims at improving the quality of the concrete used in construction projects while reducing, to the extent possible, any deviations from the quality targeted. To achieve that goal, the process capability was checked via the application of the components of the Six Sigma approach, namely: the define measure, analyze, improve, control (DMAIC). Additionally, dispersions, whenever found, were also taken into considerations with the aim being to improve each stage of the project separately. Moreover, an expert-system program was devised to facilitate the application of first, second and third elements of the (DMAIC) (i.e. the definition, measurement and analysis) while leaving the fourth element (improvement) to suggestions on what changes to be made to enhance the quality to the targeted level. Finally, accomplishing the fifth element (control) was to be done by reviewing and controlling the improvements attained through the preceding stages so as to maintain the level of Sigma accomplished. Besides its ability to achieve accurate results necessary to reach the targeted quality level, the application of the Six Sigma approach also enriches the overall process since the data collected by the tests would be part of the database to be used to feed the expert-system program, hence improving the quality of the project. As a conclusion, the research shows that applying the Six Sigma index to construction projects helps in improving the quality of the concrete consistently while maintaining the costs within specific ranges. This makes Six Sigma an appropriate approach to be adopted whenever improving the quality desired would not affect the costs, which is contrary to raising the quality of the concrete to the highest level possible, where Six Sigma appears to be inappropriate and where CPk index proves to be the best suitable alternative.