Planning with uncertainties for a heritage building restoration project in Calcutta, India

Planning for a heritage building restoration project is complex because the scope of structural repair can be only ascertained during execution. In addition, workings with traditional materials that are not normally used presently create further difficulties in planning. The restoration for great eastern hotel said to be the oldest hotel in India has been started in Calcutta, India and simultaneously, this study is undertaken to record the uncertainty of project duration and costing. A Gantt chart was prepared at the conception stage. Stakeholders were interviewed to estimate the pessimistic, mean and optimistic duration of each task in the Gantt chart. A Monte Carlo simulation based on a triangular distribution of the estimated time variations is conducted to estimate the statistics of duration. The Gantt chart is revised and simulation process is repeated with the progress of the project. The temporal distribution of time periods and associated deviations found from simulations are compared. Similar exercise is also executed for estimated costing at the various planning stages. The study indicates that a traditional Gantt chart estimate is not accurate for a project where a number of factors are unknown at the inception.