Literature review on lean implementation cases in the construction process

Lean construction is a concept still new to many in the construction iudustry around the world. All construction activities can be divided into two; conversion activities which produce tangibles aud flow activities which bind such conversion actitlities during the delivery process of the output. Although all activities expend cost and consume time, Lean Principles states that only conversion activities add value and these should be made more efficient, whereas non value-adding flow activities should be reduced or eliminated. By eliminating wasteful non value-adding activities, processes can become 'lean' which provide 'more with less' resources. Research into these lean principles in construction has found that considerable waste lies in flow activities of the construction process. However, construction contractors are mainly aware of the waste associated with material usage during the construction process and are ignorant on wastes associated with flow activities. Previous research has found major causes and types of wastes in flow activities and also that they significantly hinder performance and efficiency in the Sri Lankan construction industry. Hence, it is high time that the Sri Lankan construction industry start considering lean construction to improve its overall performance. However, the Sri Lankan construction industry lacks an implementation framework to implement lean principles into construction processes. Tbe research study, on which this paper is based on, ultimately aims to develop such an implementation framework through an action research study for Sri Lankan construction contractors. Otber countries such as the United Kingdom, United States of America, and Singapore have reaped sustainable benifits through proper implementation of lean construction. Extant literature offers several case studies of such lean construction implementations. Hence, this paper offers a critique on these case studies, as an initial step to develop all implementation framework for Sri Lanka. Accordingly, few case studies are critically compared with their construction settings. The findings reveal several similarities in the lean implementation in different settings and deviations are also identified. Tbe paper finally, identifies tbe most commonly applied lean techniques for implementing lean principles in construction processes and its benefits. It is boped that tbe key literature findings arising from this stage, will ultimately assist to develop a conceptual implementation framework using lean principles for the construction process.