042 iIntegrating Lean Construction
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The document discusses lean construction and ways to improve productivity and reduce waste in the construction industry. It explains that lean construction aims to maximize value and minimize waste through techniques like just-in-time delivery and information sharing. Other key points include identifying sources of waste at various stages, emphasizing teamwork and standardization to improve efficiency and reduce off-cuts. Overall waste reduction requires careful planning and management of materials, work processes, and the supply chain.
042 iIntegrating Lean Construction
- 3. Lean construction main objective is to maximizes value and reduces waste. It applies specific techniques in an innovative project delivery approach. including: 1. supply chain management, 2. Just-In-Time techniques.
- 5. As well as the open sharing of information between all the parties involved in the production process. Lean manufacturing is an outgrowth of the Toyota Production system. Developed by Taichii Ohno in Toyota in the 1950s.
- 6. It is based on lean manufacturing, of the Toyota Production system. Ohno learnt from mass production at Ford Motor manufacturing facilities in the U.S. and witnessed high level of waste during production.
- 7. Ohno identified several wastes in mass production systems in car industry such as: 1. overproducing 2. waiting time 3. transporting
- 8. also, in other areas such as: 1. processing methods; 2. unnecessary stock on hand; 3. unnecessary motion; 4. defective goods; 5. failure to meet customers’ needs; 6. high waste through out the process.
- 9. Womack and Jones (1996) suggested that there are five key principles that need to be monitored when lean construction systems are applied in construction. Those are: Value-clarifying the customer’s needs; the supply chain involvement in all stages, from inception to completion; By clarifying activities or products that signify value.
- 10. Value stream: By mapping the whole value stream establishing cooperation between all parties involved; identifying and eliminating waste; From taking such steps the construction process can be improved.
- 11. Flow: Business flow includes project information such as: 1. specifications 2. contracts 3. plans, etc. Job site flow involves the activities and the way they have to be carried out. Supply flow refers to the materials used in a project.
- 12. Pull: The efforts of all participants provides smooth pulls during the construction process. Perfection: Use of best methods of work instructions and best procedures. Introduction of best quality control methods.
- 14. A large proportion of the high cost in construction work is as a result of excessive labour costs. These costs can be reduced if productivity on site is increased by improving labour efficiency.
- 15. The difficulties in managing manpower on a large scale may result in productivity loss (Thomas and Jansma, 1985). There are four main factors that affect labour productivity; The duration of worker’s effort.
- 16. The intensity of worker’s effort. The effectiveness of worker’s effort combined with the technology used. The efficiency of worker’s effort, which can be described as a measure of how much the worker is utilising his ability.
- 17. Work on a complex project (e.g. such as the construction of a major shopping centre) becomes more difficult as the project advances. Off-site pre-fabrication units will reduce the number of labour hours required.
- 18. Other factors such as: the level of skill amongst the workers; the length of the workday; Innovative work practices can increase productivity.
- 19. Employment practice has an impact on the cohesiveness amongst the workforce. Some of the Important contributors towards Labour productivity are: a culture of cohesiveness common goal strong sense of a team working towards a common goal
- 20. A culture of team working involving all workers is to achieve a common goal. A common goal on construction site is to achieve KPIs. Labour productivity can also be improved if operatives on site avoid conflict. Conflict on site can hamper the progress of work. Team working reduces conflict and will greatly facilitate increased productivity.
- 21. The importance of a directly or indirectly employed workforce. and the effect on the dynamics of productivity is reiterated in several research work. The growth in the construction sector is relatively stagnant. The job security can be very bad during any recession for construction workforce.
- 23. Materials management is an important process. It is about how to reduce waste Improve productivity Follow a Sustainable development It is about how a building is designed and how materials are estimated? It is about how materials are acquired and how the packaging is specified.
- 24. It is about how the delivery schedule is designed. It is about how contractors plan materials use and how they manage previously used materials and cuts. It is about how waste is managed for use elsewhere or recycling rather than being discarded in a landfill.
- 25. Often on site usable or reusable pieces of material can be seen in a construction site. -Examples lighting ballasts, electrical switches plasterboards damaged under the rain/bad handling/storage etc. Torn bags of cement, Broken tiles, bricks, blocks, various lengths of piping and conduit. And many more.
- 26. Cost of Waste The cost of waste is more than simply the cost of getting it to a landfill and dumping it. The cost of waste is: Original cost of material Delivery cost Handling cost Management cost Cleanup cost Waste hauling cost Tipping fee =Total cost of construction waste
- 27. Materials use materials reuse, reduction and recycling begins in the planning stages of a project. 1. It starts with the architect, 2. proceeds through the engineer, the estimator, the purchaser, 3. The construction manager 4. finally the contractors.
- 28. Materials cost control often starts with a plan. Once the material is on site and especially once its been cut, it is too late to plan. With carefully well planned operational procedures and construction practices, a plan can be developed and implemented to save significant costs in materials.
- 30. Waste management on site should follow a hierarchy and have a policy of identifying why, how and where waste are occurring. Waste stream identification. The Government construction site waste hierarchy are as follow: Reduce the amount of waste produced
- 31. Re-use the material where possible Recycle the material where possible Recovery of any component parts or materials Disposal as the last resort
- 33. Standard components Off-cut waste can be very high on a construction project, Often, project dimensions may be fixed without taking into account of the standard sizes that solid materials are produced in. Benefits of using standard sizes include:
- 34. Cost savings; Improved site management; Minimization of waste and associated environmental impacts; Time can be saved; Reduction in accidents on site; Sites can be kept cleaner.