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TopLean Construction: Aspects And Benefits
Lean Production is a management-based approach to project delivery whose origin can be traced back to the developments of Toyota Automobile in Japan after World War Two. Toyota created the Toyota Production System (TPS), a system of 'lean' manufacturing which focuses on eliminating waste, creating value upstream, and eliminating non-value-adding steps while making value-adding steps flow, and pursuing perfection through continuous improvement. Researchers in the general use of lean production include Schonberger (1996), Liker (2003), Womack and Jones (2003). From the 1990s an interest started in the application of Lean Production to the construction process. Some of the very many investigations into the application of Lean to Construction include Koskela (1992, 1997), Alarcón (1997), Ballard and Howell (1997), Howell and Ballard (1998), Howell (1999), Green, (1999), Koskela et al. (2002), Bertelsen (2004), Salem et al. (2006), Johansen and Walter (2007), Sacks et al. (2009), Alarcón (2011), Sarhan and Fox (2013), Marodin and Saurin (2013). Bamford et al. (2015), and Vrijhoef (2016). This interest in Lean Construction has produced an international Lean Construction Institute (http://iglc.net/). Green and May (2005) point out that Lean Construction is “a multifaceted concept that defies universal definition” and suggest that construction academics “tend to see lean construction to be ‘inspired’ from lean production, rather than being a direct derivative.” According to Eriksson (2010) “various aspects of lean construction can be grouped into six core elements”. Eriksson names these as: waste reduction, process focus in production planning and control, end customer focus, continuous improvement, cooperative relationships, and a systems perspective. It is within the second of these aspects that what is probably the best-known manifestation of lean in construction, Ballard’s (2000) Last Planner® tool, belongs. The Last Planner® System utilises many of the lean principles listed in Sacks et al. (2010) and which are listed later. Green and May suggest that this tool has achieved a greater degree of industrial penetration than any other, and that “in some circles, ‘last planner’ and ‘lean construction’ are synonymous” as it can be “more easily ‘bolted-on’ to existing practices” (Green & May, 2005: 503). Despite the readiness to adopt lean practices (particularly Last Planner®) evidence of the results is not easy to find. This is undoubtedly due to the difficulty in isolating the effects of any intervention from those of other factors that might affect the success of a project. Perhaps the most extensive report of evidence for the benefits of Lean Construction implementation has been published by Alarcón et al. (2011) and this includes reduction of variability, manpower productivity, construction cost and schedule reductions.