A Case Study of Line-of-Balance Based Schedule Planning and Control System

Olli Seppänen¹ & Erno Aalto²

Abstract

Line-of-Balance is a graphical technique which can be used to plan and manage work flow. It is suitable for construction projects because of their large degree of repetition. Despite its strengths Line-of- Balance has not gained widespread use in construction industry internationally. However, it has been used as the principal scheduling tool in Finland since 1980s. As a result of two decades of research and use in industry, a comprehensive schedule planning and control system has been developed around location- based techniques. A computer software has facilitated implementation in construction companies. This paper describes a case study of 15,000 m2 office building project using location-based methods for schedule planning and control. Master schedule is based on Bill of Quantities where quantities have been calculated based on the project’s Location Breakdown Structure. Before implementation, different schedule alternatives were evaluated based on risk of interference, total duration and cost. During construction, the master schedule sets constraints on lower level task schedules, which were used to ensure the continuity of work for crews on a more detailed level. The master schedule was not updated even when there were deviations from the original plan. Instead the task plans were updated to catch up with the original schedule. This prevented the problems from accumulating in downstream production. In this case study the combination of PPC measurement (calculating the percentage of weekly assignments complete) and task planning was piloted. Weekly plans were made by combining assignments from all the task schedules. If the starting constraints had not been removed the task plan was updated to assess the effect on total production and to plan control actions. PPC measurement was found to improve task plan reliability. Benefits of the approach included better schedule control and possibility to examine how deviations from weekly plans affected the total schedule. Task planning provides information about how long a master schedule task actually reserves a location. This information can be used in planning master schedules of similar projects in future.

Keywords

Line-of-Balance, Scheduling, Task planning, Production control

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Reference

Seppänen, O. & Aalto, E. 2005. A Case Study of Line-of-Balance Based Schedule Planning and Control System, 13th Annual Conference of the International Group for Lean Construction , 271-279. doi.org/

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