Optimal berth scheduling and sequencing under unexpected events

The berth scheduling problem (BSP) at container ports has received significant research attention. Nevertheless, few studies considered the BSP under emergent ship arrivals. Thus, this paper proposes an optimization procedure for scheduling and sequencing of ship arrivals at container port under the occurrence of unexpected events; emergent ship arrivals. Three consecutive models are proposed to maximize the number of served emergent ships at minimal disturbance to service schedule of regular ships. The first model schedules and sequences service of emergent ships at available idle berth(s). The remaining unscheduled emergent ships are then assigned by the second model, which attempts to serve those ships in untapped ranges between the scheduled regular ships. If some emergent ships are still unassigned in the untapped ranges, the third model finally resequences the service schedule of regular ships at the berth of the largest free margin to serve those emergent ships. A case study is employed to illustrate the proposed optimization procedure; where the results showed that the proposed models efficiently solved BSP at acceptable satisfaction levels for both regular and emergent ships. In conclusion, the proposed models may provide valuable support to decision makers in dealing with BSP under emergent ship arrivals.