University of Twente Student Theses


Lean plannen van het ontwerpproces

Huet, J.G.F. van (2015) Lean plannen van het ontwerpproces.

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Abstract:Traditional scheduling methods, which are based on the push approach of scheduling, are unable to reliably schedule the design process with integrated contracts in infrastructure projects. These methods do not support the dynamic character of the design process and the complexity of these projects. The dynamic character is the result of the uncertainty in goals, the iterative nature and the limited time available for realizing the design. The complexity of these projects arises from the highly multidisciplinary character, integrated contracts en size. Therefore, Heijmans Infra B.V. started to use the Lean Engineering (LE) steps additional to the standard scheduling approach. In this research, the standard scheduling approach and the LE steps are called the current scheduling method. The current method seems incomplete and does not lead to ‘best practices’. In order to look for improvements, the Last Planner System (LPS) is used as conceptual framework for this research. The LPS is used because of its lean basis, which Heijmans Infra B.V. prefers. Additionally, it might suit the dynamic character of the design process. This, because the LPS focuses on which activities really ‘can’ be done, instead of scheduling which activities ‘should’ be done according to predetermined milestones. Methodology The conceptual framework of this research is based on the LPS. The current scheduling method is established by documentation which describes the method and by observation in practice at three cases. Then the current scheduling method has been compared to the conceptual framework, which leads to differences between these two. Based on the cases and interviews, findings on the current scheduling method are drawn. By putting the differences in relation with the findings, it is concluded how these differences should be handled. Finally, improvements on the current scheduling method are formulated. Herewith, an improved scheduling method is created. Conceptual framework The conceptual framework consists of four scheduling levels. Herewith, the detail of scheduling becomes higher as activities come closer. The scheduling levels are the long term‐, average term‐, short term‐ en week schedule. At every level the characteristics en applied elements of the LPS are identified. The characteristics are the level of detail, the length of the scheduled period, the basis of the schedule, the goal of the schedule and who the planners of the schedule are. The elements are collaborative scheduling, constraints analysis, the lookahead process, reliable promising, root cause analysis and applying measurements (PPC, TA and TMR). Empirical The current scheduling method only has three levels which match the long‐, average‐ and short term schedule of the conceptual framework. Week scheduling is not applied in the current method. No differences arise by comparing the long term schedule. The characteristics of the remaining scheduling levels largely match the conceptual framework. The only difference is that on the short term schedule the schedule is based on what activities ‘should’ be done, while with the conceptual framework is scheduled which ‘can’ be done. Collaborative scheduling, constraints analysis, reliable promising and measuring the PPC are partly done with the current scheduling method. The lookahead process, root cause analysis and measuring the TA and TMR are not yet applied. Findings of the cases and interviews show that the average term schedule is highly unreliable. Also, this schedule does not offer reliable input for the short term schedule. The short term schedule itself however is reliable and constraints are solved in time. Conclusions In order to schedule more reliable on the average term schedule, collaborative scheduling and constraints analysis should be applied. Herewith, a more reliable schedule is realized since constraints are identified, defined and coördinated. Identifying and defining is done by the constraints analysis, while collaborative scheduling makes sure these constraints are coördinated. To facilitate these elements the LE steps can be used. The steps proved to be effective to support collaborative scheduling and constraints analysis. Concerning the short term schedule, applying the lookahead process will improve the reliability of the schedule. With the lookahead process a constant period (ca. six weeks) is scheduled ahead and the schedule is evaluated weekly. Herewith, the constraints in the schedule are updated weekly sothat it stays reliable. Additionally, this supports scheduling what really ‘can’ be done instead of what ‘should’ be done according to predetermined milestones. There is no cause found for applying a separate week schedule. Altough two elements of this level will raise the reliability of scheduling. Firstly, applying root cause analysis on deviations in the schedule will result in more reliable schedules on the long run. Namely, more measures will be taken to solve the causes of deviations. Secondly, applying the measurements (PPC, TA & TMR) will indirectly lead to more reliable schedules, since these can be used as Key Performance Indicators (KPI’s) for the reliability of scheduling.
Item Type:Essay (Master)
Faculty:ET: Engineering Technology
Subject:56 civil engineering
Programme:Civil Engineering and Management MSc (60026)
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