Browsing by Author "Kenley, Russell"

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    Case Studies of Using Flowline for Production Planning and Control
    (2005) Kenley, Russell; Seppänen, Olli; Department of Civil and Environmental Engineering; Dynamic System Solutions Ltd
    Flowline, or Line-of-Balance, has recently gained attention in Lean Construction literature because of its capacity for facilitating control of production flow and planning of continuous work. In the broader technical literature, previous work has concentrated on the analytic properties of flowline, such as learning curves, and is generally silent on how the method should be used to improve productivity. This is because internationally the technique has received relatively little application. However, in Finland, flowline has been used as the principal scheduling method since 1980s. This paper takes a practical approach and describes the use of flowline based planning and control in two real case projects. One of the projects is a large residential construction project in Sydney, Australia. The other project is a Finnish retail park construction project. These pilot projects were done at the same time and the projects were able to learn from the experiences of the other. The cases highlight the differences between the Finnish way of planning a schedule with buffers between activities with synchronized production rates and the Australian way of driving a schedule with a tightly constrained CPM schedule. A methodology using flowline as a visual planning tool but using familiar CPM logic as the underlying engine was appropriate in the Australian case. In this methodology the objective is to improve site control by including information about location and to be able to plan continuous work for subcontractors and to visualize the effects of planning decisions. The result is much clearer communication to the trade contractors about the timing and location of their work, improved control systems and better work flow. The Finnish project team was already familiar with the basic use of flowline so the more advanced risk management based approach was used. The risk management based approach includes using quantities estimated by location as the starting point and optimizes the crews so that the risk of schedule disturbances is minimized. The planning happens on two levels: the master schedule has less detail and the task plans are detailed plans of individual tasks which are done by persons responsible for the work when all the necessary information about implementation is available. The results from the Finnish case include a methodology for effectively controlling production flow and how to include the subcontractors in the process. 109 Comparison of the two different strategies reveals important knowledge about the role of custom in scheduling, and reveals potential barriers to adopting innovative approaches.
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    Performance Measurement using Location-Based Status Data
    (2005) Seppänen, Olli; Kenley, Russell; Department of Civil and Environmental Engineering; UNITEC Institute of Technology; Dynamic System Solutions Ltd
    Much attention has been placed on measuring performance of activity completion in Lean literature, using techniques such as Percentage of Planned Activities Completed (PPC). Originally intended as one component of measuring plan execution, along with measures of Planned Productivity, PPC has been extensively researched but Planned Productivity has been neglected. Using a lean methodology based on location-based scheduling enables an alternative performance measurement system. This paper proposes a method which makes possible the gathering of large amounts of performance data without too much effort. The method is an important contribution to the available suite of lean methods. Performance measurement using location-based status data is a method which has much in common with earned value analysis, and is able to use the progressive performance through each location of the project as the unit of measurement. The equivalent indicator to PPC is provided by measuring against the planned completion of a location. Furthermore, before commencing work the site checks the actual quantities in each location. Planned Productivity is measured during implementation, with the start date and finish date, actual quantities and average resources used in each location being recorded. This information can be used to calculate actual productivity. The location-based data gives the ability to measure within tasks, revealing not just completion of stages as in PPC, can measure against Planned Productivity. The actual productivities can be used to forecast problems in the future and to evaluate the feasibility of alternative control actions. In addition, the location-based actual information combined with the original Bill-of-Quantities and schedule reveals the erroneous assumptions made during preplanning and facilitates learning on future projects.
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    Using location-based techniques for cost control
    (2005) Seppänen, Olli; Kenley, Russell; Department of Civil and Environmental Engineering; UNITEC Institute of Technology; Dynamic System Solutions Ltd
    Performance measurement is an important component of lean-based management systems, however cost management systems or analysis have largely been applied at a high level and have not attempted to measure or model the production cost impacts of disruption on a lean project. While it is important to develop systems for practical site management, it is equally important to ensure that such systems can accommodate mainstream performance measurement systems. In this paper, the performance system known as Earned Value Analysis is adapted to a location-based method for planning and control-ling work known as flowline or line-of-balance. The resultant method for forecasting cash flow, modeling the costs of interference and controlling costs, is described. The method is compatible with location-based scheduling methods. It uses location-based quantities and their unit prices as starting data. Because the location-based quantities are also used in developing the flowline schedule, the start and finish date for each quantity is also known. This information can be used to calculate cash flow more accurately than previously. In the preplanning phase, quantity estimates and estimated prices are used to create a location-based cost estimate. During the production phase, more accurate quantity data is available and prices from contracts can be used directly to arrive at a first cost forecast, before commencing the work. When the work is being done, cost controlling can be done by surveying the actual quantities of each location. The cost forecast is then updated based on these actual quantities and using the contract prices. The location-based schedule forecast can be used to forecast overhead costs and to forecast costs of interference. The paper contributes to our understanding of monitoring and control in a flowline-based management system in a lean-construction methodology. It also demonstrates that effective location-based control of the payment system allows better management of sub-contractors during production.