Lean construction is a combination of operational research and practical development in design and construction with an adoption of lean manufacturing principles and practices to the end-to-end design and construction process.
Paradigm Lean construction required the application of a robust programmatic framework to all repair, renovation, maintenance, and or new build activities. While each project may be unique, the application of LEAN fundamental should be applied consistently. Lean construction is concerned with the alignment and holistic pursuit of concurrent and continuous improvements in all dimensions of the built and natural environment: design, construction, activation, maintenance, salvaging, and recycling. This approach tries to manage and improve construction processes with minimum cost and maximum value by considering customer needs.
Historical development The origins of many fundamental concepts of LEAN and LEAN construction date back in time.
The origins of foundational LEAN concepts can be traced back to the 1450s in Venice, but the concept is often associated with Henry Ford and Toyota in the 20th century. LEAN was first applied in "modern day" production management by Henry Ford, and his ground-breaking automobile manufacturing company in the early 20th century. Students of LEAN history should begin with the Ford manufacturing plant in Highland Park, Michigan, USA., in 1913. Manufacturing process thinking dates even further back to Arsenal in Venice in the 1450s A lean "thought process" was introduced in The Machine That Changed the World in 1990, however, it and subsequent iterations focus largely on FLOW. While FLOW is important, the achievement of efficient flow, must involve the integration of planning, procurement, and project delivery within a common data environment. This aspect was not addressed significantly, if at all. It was initially implemented in construction, however, via Job Order Contracting in the 1980s (which has subsequently evolved substantially) and later with Integrated Project Delivery. Lauri Koskela, in 1992, challenged the construction management community to consider the inadequacies of the time-cost-quality tradeoff paradigm. Another paradigm-breaking anomaly was that observed by Ballard (1994), Ballard and Howell (1994a and 1994b), and Howell (1998). Analysis of project plan failures indicated that "normally only about 50% of the tasks on weekly work plans are completed by the end of the plan week" and that constructors could mitigate most of the problems through "active management of variability, starting with the structuring of the project (temporary production system) and continuing through its operation and improvement".
Evidence from research and observations indicated that the conceptual models of Construction Management and the tools it utilizes (work breakdown structure, critical path method, and earned value management) fail to deliver projects "on-time, at budget, and at desired quality". With recurring negative experiences on projects, evidenced by endemic quality problems and rising litigation, it became evident that the governing principles of construction management needed revisiting. One comment published by the CMAA, in its Sixth Annual Survey of Owners (2006), pointed to concern about work methods and the cost of waste: "While the cost of steel and cement are making headlines, the less publicized failures in the management of construction projects can be disastrous. Listen carefully to the message in this comment. We are not talking about just materials, methods, equipment, or contract documents. We are talking about how we work to deliver successful capital projects and how we manage the costs of inefficiency."
A new paradigm Koskela (2000) argued that the mismatch between the conceptual models and observed reality underscored the lack of robustness in the existing constructs and signaled the need for a theory of production in construction. Koskela then used the ideal production system embodied in the Toyota Production System to develop a more overarching production management paradigm for project-based production systems where production is conceptualized in three complementary ways, namely, as a Transformation (T), as a Flow (F), and as Value generation (V).
Transformation is the production of inputs into outputs. Flow can be defined as "Movement that is smooth and uninterrupted, as in the 'flow of work from one crew to the next' or the flow of value at the Pull of the customer." Value is "What the Customer is actually paying for the project to produce and install." Koskela and Howell (2002) also presented a review of existing management theory – specifically as related to the planning, execution, and control paradigms – in project-based production systems. Both conceptualizations provide a solid intellectual foundation of lean construction as evident from both research and practice. Recognizing that construction sites reflect prototypical behavior of complex and chaotic systems, especially in the flow of both material and information on and off site, Bertelsen (2003a and 2003b) suggested that construction should be modeled using chaos and complex systems theory. Bertelsen (2003b) specifically argued that construction could and should be understood in three complementary ways:
As a project-based production process As an industry that provides autonomous agents As a social system
What is lean construction?
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