Effects of block lengths and stacking policies on overall performance at non-transshipment container terminals

The ever-increasing worldwide container throughput and the intensified port competition have demanded better terminal operational performance, which is usually measured by the gross crane rate (GCR). In this paper, a multiagent-based simulation model is proposed to investigate how the block length of the storage yard and the tactical-level stacking policy affect the operational performance of non-transshipment container terminals over the long term. Experiments consider seven block lengths, two yard truck fleet sizes and two stacking policies. The results demonstrate that the best block length yielding the highest GCR is dependent on the stacking policy and the yard truck fleet size, and the separate stacking policy is essentially superior to the scattered stacking policy. Specifically, only when 9-yard trucks are deployed per quay crane under the separate stacking policy, can the typical 42-slot block length achieve the highest GCR. Although the experiments are not exhaustive, they do provide the first fundamental insights, with respect to the effects of block lengths and stacking policies, on the long-term performance at a manually controlled non-transshipment container terminal.

Performance Comparison of Real-Time Yard Crane Dispatching Strategies at Nontransshipment Container Terminals

Yard crane operations are often a bottleneck at a container terminal. This paper aims to investigate the effects of various real-time yard crane dispatching strategies on operational cost and gross crane rate (GCR) for nontransshipment container terminals. A general cost estimation model is introduced to incorporate the detailed costs incurred during container handling process within terminal area. The formulas of container handling related parameters are mathematically derived to validate the simulation model. Results reveal that the common nearest truck first served strategy yields the lowest operational cost but the lowest GCR. On the other hand, earliest YT strategy achieves the highest GCR at the expense of higher operational cost with more vessel calls, while nearest YT strategy produces the highest GCR and is the second economical with fewer vessel calls. Under any of the proposed yard crane dispatching strategies, the strategy that separately stacks import and export containers into different blocks outperforms the scattered stacking strategy in terms of GCR, although no distinct cost advantage is obtained. The results provide fundamental insights into the connection between real-time yard crane dispatching strategies and operational performance at manually controlled nontransshipment container terminals.