An Improved Approach to the Lean Subcontracting Procurement Process (LSPP) for Construction Contractor with Cases
| Autor: | Ngo Thanh Long, 吳青龍 |
|---|---|
| Rok vydání: | 2012 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 101 Realizing and reducing types of waste in construction projects are very important to both construction contractors and owners. Waste in the construction industry is an interested problem that has been cared by all society such as government, owner, construction contractor, and so on. Waste not only reduces benefit of all participants in construction projects, but it also causes environmental pollution. In addition, some studies have concluded that waste level in the construction industry is relatively high. However, most previous studies have focused on ways to eliminate individual types of waste, and they have not proposed a method to eliminate main types of waste in construction projects. Early planning in the subcontracting procurement is an essential function of construction project management, and it allows construction contractors to obtain projects with low cost while achieving other criteria, such as quality, time, and safety. Early planning in the subcontracting procurement also helps contractors during the whole project execution and management since it establishes the benchmark for the control system to track the quality, cost and time of project. The traditional planning model often bases on only the transformation (task) concept of production under the assumption, which considers the task, is a production process, while flow (workflow) and value generation concepts are often ignored. In contrast, the workflow concept is an important contributor for planning the construction project because it addresses the high levels of waste in the workflow. However, there is limited research regarding planning model; most research has focused on planning tools and techniques as opposed to the planning process. Moreover, most of the research on planning relates to the environment, transportation, the owner planning process, scope definition, and water planning. Construction contractors tend to not be concerned with the early plan. As a result, many problems relating to planning, including wasted time, delays, and poor communication, exist in construction projects. The subcontracting procurement process is one of the most important issues impacting the costs of engineering projects and construction projects, in particular. Traditional procedures of subcontracting procurement tend to limit the opportunities for price negotiation and cooperative relationships between contractors and neglect potential issues such as engineering interface, construction risk, and waste. Traditionally, the subcontracting procurement almost always uses price negotiation and price competition in order to lower the price of the project. This method aims to reduce labor, machine, equipment, and material costs while maintaining quality and meeting the project owner’s requirements. However, this procurement method has four main weaknesses: (1) wastage such as time, material, machine, manpower, etc., which can accumulate and prove costly for a project; (2) this procurement limits the opportunities for price negotiation; (3) potential issues with the engineering interface and construction risks are often neglected during price negotiation; (4) relationships between contractors are competitive and adversarial, and it has not promoted innovation. Despite the many studies on the procurement of subcontractors, the focus of these studies has been limited to the selection of a subcontractor, subcontractor selection criteria, subcontractor rating techniques, and use of internet and artificial intelligent in selecting or evaluating subcontractor. Moreover, these studies do not address how a subcontractor might eliminate waste, predict risk, and achieve cooperative relationships with other contractors during the procurement and construction processes. Firstly, this research identified seven major types of waste in construction projects, and it applied the manufacturing industry’s lean theory to propose three important methods that can effectively eliminate types of waste in the construction projects. Secondly, the research proposed a lean planning model (LPM) for construction contractors. The LPM can significantly eliminate the main types of waste in construction projects because it effectively combines three important concepts of production: transformation (T), flow (F), and value generation (V). This model includes seven arrangement steps, which are described systematically to help contractors with real-world applications. The method of LPM is based on an integration of TFV concepts. Thirdly, based on case studies of construction projects, the research proposed a lean subcontracting procurement process (LSPP) drawing from lean construction theory. The model consists of a novel Seven-Arrangement operation plan and four types of standard operating flows. Not only does the proposed LSPP help subcontractors eliminate various types of waste in construction projects, it also establishes a common information platform and cooperative environment that help participating contractors understand the work emphasis of each operation and the whole operation in sequence. As a result, the relationships between participating contractors become cooperative, potential risks in construction projects can be discovered early, and profits are shared between contractors. Thus, this process allows contractors to obtain long-term benefits and improved elimination of waste. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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