The Concept of Float Calculation Based on the Site Occupation using the Chronographical Logic

Precedence logic's consider time as the only constraint for float computation. By neglecting resource and working areas availabilities, the accuracy of the schedule is affected. The overuse of labor regardless of location may create workspace congestion, affect negatively the productivity and create an optimistic critical path. Conversely, the underuse of work locations can unnecessarily lengthen the critical path. The margin computation will inherit such optimism/pessimism. This paper explains the concept of margin calculation based on the site occupation using the Chronographical modelling. The critical path is leveled, according to the occupancy rate of the site, by relaxing or compressing the project. The rate considers the category of location (e.g. corridor or closed room) and the activity type (e.g. divisions, flooring or electrical finishing works). The method proposes five levels of layers for spaces management according to the stage of construction, namely the creation of spaces (e.g. addition of new floors); the systems (e.g. ventilation ducts); the division of spaces (e.g. partitions); the finishing (e.g. painting) and the closing of spaces (e.g. carpet laying'). Compression or relaxation could be achieved by decreasing or extending the activities durations' by adjusting the working hours or the number of teams or peoples, or by varying the overlap rates between activities. The method thus establishes a level of risk of the completion of the project duration according to the level of criticality of the activities and locations occupation rates according to the choices made by the user. The proposed coordination method demonstrates the relevance of using other measures, including the workspace occupation rates or by freeing or blocking zones, for the scheduling calculations. The proposed chronographic logic and margin computations can then be used to simulate the project's real conditions.