Dynamic production-based relationships between activities for construction projects planning

The schedule logic for construction projects is usually represented by a bar chart diagram that shows precedence dependencies between activities. Relationships may use lags in order to permit overlapping between activities. For these precedence point-to-point external relationships, the difficulty of representing interdependencies and overlapping has imposed, in the past, the study of the impact of the upstream activities over the downstream activities using concurrent engineering concepts (Eppinger, 1997). Song and Chua (2007) present a temporal logic intermediate function relationship based on an interval-to-interval format rather than time points through the intermediate functions. To address a practical solution, the Chronographic Model (Francis and Miresco, 2006) introduces the internal division concept and internal measurement as a function of production: we refer to this as the Temporal Function. This paper reviews and analyses the roles, advantages and disadvantages of Temporal Functions and introduces production-based dynamic relations between the interlinked activities. The internal dependencies between any two activities can be represented by a mathematical function. These functions could also be probabilistic, which means that they permit a certain gap in the interdependence of activities. In figure 1 the two activities Excavation and Foundation depend on each other throughout their execution. In these circumstances, these two activities are dependent activities. Any adjustment in the productivity of one of them affects the other one.