Line-of-balance is a visual scheduling method which is suitable for construction projects because of their high degree of repetition. Line-of-balance allows the planner to explicitly account for flow of a project. To help effective project control line-of-balance enables drawing of actual lines next to the original plan. This allows for analysis of deviations during implementation. Forecasts can be made by continuing the actual lines with the same slope to show the total effect of deviations. If the forecast lines collide with each other, there will be problems as many crews will be working in the same physical space at the same time. In this paper the main types of deviations and their effects are described with line-ofbalance figures. Possible control actions and their effectiveness are examined. The prevalence of deviations and problems with production flow are shown by analysing the implementation on real projects which have the actual lines drawn next to the planned ones. The production rate deviations and interruptions of project flow were quantified. The main result of the research was that controlling of production and actively reacting to deviations is ineffective even if production start prerequisites exist. As a consequence, the production start prerequisites are lost for the succeeding tasks and the work flow is broken. The actual Lineof-Balance figures show graphically the resulting chaotic situation.
Line ofbalance, scheduling, schedule control, flow, control actions, deviations
Seppanen, O. & Kankainen, J. 2004, 'Empirical Research on Deviations in Production and Current State of Project Control' In:, Bertelsen, S. & Formoso, C.T., 12th Annual Conference of the International Group for Lean Construction. Helsingør, Denmark, 3-5 Aug 2004.