Highway infrastructures in North America have surpassed their service life, and the transportation developments are shifting from construction of new highways to reconstruction of existing facilities. Elevated urban highway reconstruction projects involve complex geometry and limited space available which lead to spatio-temporal conflicts. Additionally, maintaining acceptable flow of traffic without compromising safety in highway construction zones is another major issue for planners. Overall, the phasing of construction work in such projects is complicated due to the structural complexity, large number of involved contractors, independent resource utilization planning by each contractor, and the vast number of activities that will be taking place at the same time.
This research proposes a new methodology by integrating 4D modeling and simulation in the planning and scheduling phases of elevated urban highway reconstruction projects to detect spatio-temporal conflicts. A sequence assessment approach using a deterministic 4D model is presented to define the order in which the segments should be constructed or demolished. The result of this step is a sequence which will be used as the process chain for simulation techniques. Then, a probabilistic 4D model is introduced by linking the 3D model of the project with generated probabilistic schedules from Monte-Carlo and Discrete Event simulations. The proposed approach is capable of identifying scenarios with the highest potential of conflict and calculating the probability associated with each scenario. The benefits of the proposed approach are highlighted, and the feasibility of the proposed methods is explored through three case studies.