Synchronized optimization of various management-function schedules in a multiproject environment: Case study of planning steel girder fabrication projects in bridge construction

Structural steel prefabrication is a generally accepted practice in the construction industry conducive to better control of project duration and cost, higher productivity and efficiency, and enhanced quality and safety performance. This study initiated with an investigation of the current practice of major structural steel fabricators in Alberta, where skilled trades rather than fully automated equipment remain the critical resources in production planning and scheduling. How to synchronize the schedules of concurrent projects at different levels to optimize the allocation of fabrication resources (particularly skilled laborers) is identified as a matter of pressing concern in the industry. In collaboration with an industry partner in Edmonton, Alberta, Canada, we (1) developed a unified work breakdown structure (WBS) based on project management functions such as bidding, production planning, estimating, and scheduling; (2) synchronized schedules for various management functions by implementing a dual-level multiproject optimization scheduling framework; and (3) developed a multiproject scheduling tool to implement the research in practice. A case study of the fabrication of steel girders for three bridges investigates the benefits of the proposed scheduling approach to the fabrication process, which include improved alignment between shop operation progress, individual project objectives, and overall program goals.