Scheduling optimization of linear projects considering spatio-temporal constraints

Overall schedule optimization, considering all temporal, spatial and precedence constraints is a difficult task due to the complexity which is inherent in construction projects. The difficulties associated with modeling all aspects combined become more considerable when optimizing linear type of projects with high activities’ inter-relations. The progress of these projects highly depends on the productivity achieved from their resources which is directly dependent upon the space and time available to these resources. As a result, in order to practically optimize linear schedules, not only their achieved productivities need to be managed well, but also the spatio-temporal flexibilities and constraints are to be integrated into the optimization process. This paper aims to fill the gap in the current literature by proposing a practical approach for modeling and optimization of linear schedules while taking into account all the project-dependent constraints. For this purpose, the methodology is built on the new concept of Space-Time float for explicit consideration of spatio-temporal constraints of activities. The developed method uses constraint-satisfaction optimization approach to minimize duration of the generated schedules. As such, by having Space-Time floats for different activities’ resources and using such constraints, the schedule is optimized to get the minimum achievable duration for the total project. A numerical example is analyzed to present the proposed and developed method as well as its added benefits.