A framework to improve construction processes: Integrating lean, green and six sigma

The construction industry consumes a significant amount of resources annually, generates significant waste and produces a host of emissions. This study develops a framework and integrates three different approaches - Lean, Green and Six Sigma - in a systematic approach with the goal of improving the quality and environmental impacts of the construction process. A case study of pile cap installation was conducted to illustrate the application of the framework and associated results. The study highlights two issues within the pile cap construction process responsible for waste: delay and potential errors in material estimation and ordering. It describes the environmental impact arising from waste, and analyzes the root causes behind waste generation to enable improved process performance. A survey of construction professionals regarding the causal factors of waste in everyday construction activities identified 'design changes during construction' as responsible for 60% of waste occurrences during construction and thus confirm results from the literature. In conclusion, the Lean- Green-Six Sigma framework offers a comprehensive, multi-stage approach for process improvement and minimization of life cycle environmental impacts.