استفاده از تفکر ناب در ساخت و ساز و بهبود عملکرد
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|12413||2013||17 صفحه PDF||سفارش دهید||10830 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Alexandria Engineering Journal, Volume 52, Issue 4, December 2013, Pages 679–695
The productivity of the construction industry worldwide has been declining over the past 40 years. One approach for improving the situation is using lean construction. Lean construction results from the application of a new form of production management to construction. Essential features of lean construction include a clear set of objectives for the delivery process, aimed at maximizing performance for the customer at the project level, concurrent design, construction, and the application of project control throughout the life cycle of the project from design to delivery. An increasing number of construction academics and professionals have been storming the ramparts of conventional construction management in an effort to deliver better value to owners while making real profits. As a result, lean-based tools have emerged and have been successfully applied to simple and complex construction projects. In general, lean construction projects are easier to manage, safer, completed sooner, and cost less and are of better quality. Significant research remains to complete the translation to construction of lean thinking in Egypt. This research will discuss principles, methods, and implementation phases of lean construction showing the waste in construction and how it could be minimized. The Last Planner System technique, which is an important application of the lean construction concepts and methodologies and is more prevalent, proved that it could enhance the construction management practices in various aspects. Also, it is intended to develop methodology for process evaluation and define areas for improvement based on lean approach principles.
Since the 1950s, lean production or Toyota production system principles have evolved and were successfully implemented by Toyota Motor Company. Toyota production system had two pillar concepts: (1) Just In Time flow (JIT) and (2) Autonomation (smart automation) as shown in more details in Fig. 1.The term “lean” was coined by the research team working on international auto production to reflect both the waste reduction nature of the Toyota production system and to contrast it with craft and mass forms of production . Starting from efforts to reduce machine setup time and influenced by TQM, a simple set of objectives was developed for the design of the production system including to (1) Identify and deliver value to the customer value: eliminate anything that does not add value; (2) Organize production as a continuous flow; (3) Perfect the product and create reliable flow through distributing information and decision making; and (4) Pursue perfection: Deliver on order a product meeting customer requirements with nothing in inventory. Lean production aims to design and make things differentiated from mass and craft forms of production by the objectives and technique, and to optimize performance of the production system against a standard of perfection to meet unique customer requirements. In the beginning of the 1990s, the new production philosophy, which is known by several different names, is as follows: (1) world class manufacturing; (2) lean production; and (3) new production system. This philosophy is the emerging mainstream approach. It is practiced, at least partially, by major manufacturing companies in America and Europe. The new approach has also diffused to new fields, like customized production, services, administration, and product development. Since 1992, Koskela  has reported the adaptation of lean production concepts in the construction industry and presented a production management paradigm where production was conceptualized in three complementary ways, namely as (1) Transformation; (2) Flow; and (3) Value generation (TFV) theory of production. This tripartite view of production has led to the birth of lean construction as a discipline that subsumes the transformation-dominated contemporary construction management  and . Managing construction under lean is different from typical contemporary practice because it (1) has a clear set of objectives for the delivery process; (2) is aimed at maximizing performance for the customer at the project level; (3) designs concurrently product and process; and (4) applies production control throughout the life of the project. The first goal of lean construction must be to fully understand the physics of production, the effects of dependence and variation along supply and assembly chains. In lean construction as in much of manufacturing, (1) Planning: defining criteria for success and producing strategies for achieving and (2) Control: causing events to conform to plan, and triggering learning and re-planning are two sides of a coin that keeps revolving throughout a project. In this research, principles, methods, and the implementation phases of lean construction will be discussed showing the waste in construction and how it could be minimized. The Last Planner System (LPS) technique, which is an important application of the lean construction concepts and methodologies and is more prevalent, proved that it could enhance the construction management practices in various aspects and bring numerous advantages, so that the construction projects will be more stable and less stressful for all involved stakeholders by reducing dependencies and variations to identify and eliminate waste (non-value adding activities).
نتیجه گیری انگلیسی
This research seeks to confirm the following objectives: (1) Determine the implementation of lean ideal; (2) Identify the source of wastes classified under lean construction industry; (3) Examine general perceptions of the construction industry with the lean construction principles of practices; (4) Study reduction and elimination of wastes as classified under development of Last Planner System as a technique of lean construction implementation and to evaluate the effectiveness of implementing last planner to increase plan reliability; (5) Examine the relationship between lean construction and performance improvement programs in construction organizations; and (6) Analyze the characteristics of successful performance improvement programs, and develop a model that identifies three critical elements: (a) Time spent on improvement, (b) Improvement skills and mechanisms, and (c) Improvement perspective and goals. The authors identify different ways to structure improvement program: outcome focused (such as Critical Success Factors) and process-focused (such as Lean Construction). The paper discusses the implications of the different perspectives and argues that they lead to different improvement approaches each reflecting different paradigms for the nature of the change. The authors propose that result-focused improvement programs may be a barrier to the adoption of Lean Construction. The paper proposed a dynamic model of performance improvement process. The model examined the factors affecting the process and their interactions. The paper proposed that: (1) Direction of the improvement effort is strongly influenced by the structure and goals; and (2) Result-focused programs have limited ability to address complex systemic problems. One question for future research is what drives a contractor to establish a result-focused or a process-focused program. It appears that specialty contractors are more familiar with the process-perspective because of their familiarity with productivity improvement studies (which is a process analysis of a relatively simple problem). On the other hand, general contractors are more likely to emphasize overall project results. Future research also needs to (1) Develop and validate a more complete model of performance improvement; (2) Further examine the behavior of improvement process over time; and (c) Use the model as a starting point for system redesign by adding loops and breaking links.