Project duration evaluated using affine arithmetic

A civil engineering work can be performed by organizing the available resources (manpower, equipment and materials) in many different ways. Each different configuration results in a realization time and a cost that a building company has to bear. To produce reliable duration forecasts and money savings, it is essential to take into account all the uncertainties involved in the project operations. Generally, since it is impractical to process numerous uncertain variables - also undefined from a statistical point of view -, traditional probabilistic methods involve application difficulties for complex environments such as construction sites. To properly handle this issue, the authors propose in this paper the application of the Affine Arithmetic technique. This method treats the variables as intervals and returns reliable results, even when the variables are mutually dependent. The numerical example presented in the paper proves the efficiency of the procedure, even if some analytical complications are included in the analysis (dependency between variables, non-linear functions, etc.). Comparisons with Interval Analysis and traditional procedures are also provided, Adopting Affine Arithmetic, the results are reported in terms of intervals, avoiding the definition of unrealistic deterministic values that can strongly affect the operation organization. Furthermore, without increasing the problem complexity, the model admits continuous modifications (interval amplitudes, new variable dependencies, etc.) to correct and optimize the durations.