T. Vellinga

Network Capacity Estimation of Vessel Traffic: An Approach for Port Planning

Port capacity is an essential parameter for the assessment of port performance. In the literature, there is no unanimous capacity definition, which depends on each research goal. Vessel traffic in ports and the corresponding port performance indicators have been analyzed with different simulation models, but they generally do not include a method for determining a port’s capacity. Guidelines or other studies using empirical data also have not addressed this important topic. The method developed in this paper estimates the port network traffic capacity (PNTC) by using vessel traffic data. The analysis and comparison of several indicators are used to identify meaningful relationships for estimating port capacity with generic applicability to any port design. The relation between the total number of trips in the port and the ratio of waiting time to service time seems to be the most suitable for identifying when the port reaches unstable flow situations, that is, when it reaches capacity. The method has been applied successfully in six scenarios with various berths, layouts, service times, vessel fleet types, and maneuvering times. Application of the method is useful during the port-planning phase, because with a few simulations, an indicative PNTC value for each design can be inferred, and thus, different scenarios can be compared.

Role of Flexibility in Sustainable Port Development

Sustainability has become a high profile objective in all aspects of our lives, including the development of our infrastructures. Flexibility can enhance sustainability endeavors, yet its contribution is not clear to most. In this paper we investigate the role of flexibility in sustainable port development in order to promote its incorporation in port projects. We establish that the greatest payoffs from flexibility are achieved through initiating new life cycle for a capital intensive port infrastructure, though reuse of the elements and materials also contributes to flexibility. Reuse concurrently optimizes use of natural resources, limits waste and pollution in the environment, conserves energy, and thus limits the overall negative ecological impact. It also results in significantly lowers lifecycle costs. Thus flexibility helps achieve (long-term) financial viability in face of economic uncertainty, while reducing environmental and social impacts. Therefore, flexibility considerations are important during design, procurement, and contracting of engineering projects. The best way to redirect the choice of decision-makers towards flexibility is to make visible its long-term benefits, and its contribution to sustainability. We discuss some evaluation methods and propose that the quantitative methods are more likely make a case for flexibility.

Capacity Estimation Method of a Waterway Intersection

The growth of maritime transportation leads to more crowded and intensively used waterways . This research presents a method to estimate the capacity of a waterway intersection. An analogy between roads and waterways is used and the conflict technique is applied to a waterway intersection. The flows in each direction and their conflicting movements lead to the capacity calculation. Data analysis provides insight into vessel behaviour in an intersection. Moreover, the value of the method has been proven with a case study. This is a generic method that can be applied in any waterway intersection based on the conflicts between the different sailing directions in the intersection and the flow shares inferred from empirical data or predictions. Its application can improve traffic management strategies or traffic rules in waterway intersections.