The impact of automation on the efficiency and cost effectiveness of the quayside and container yard cranes and the selection decision for the yard operating systems
This research evaluates the impact of automated and semi-automated devices on the process of loading, discharging, stacking and un-stacking of containers using Quayside Cranes (QSCs), Straddle Carriers (SCs), Rubber Tyred Gantry cranes (RTGs) and Rail Mounted Gantry cranes (RMGs) in container terminals. The emphasis of study is on the assessment of performance and cost effectiveness of the existing automated quayside and yard cranes. The study in this thesis examines the economic implications of reducing QSCs' cycle-times brought about by automatic features installed on the post-Panamax cranes. It demonstrates that a considerable increase in the productivity of QSCs is related directly or indirectly to an expected reduction of crane cycle-times. The concept offered by the proposed improvements distinguishes between the traditional system of loading and discharging of containers and the automated methods. It implies that automation devices installed on conventional QSCs significantly reduce the total turnaroundtime and hence the cost of containerships' waiting-times. It argues, however, that there should be a balance between the cost of containerships' waiting-times and the cost of automated berths' unproductive-times (idle-times). This study uses the elements of queuing theories and proposes a novel break-even method for calculating such a balance. The number of container Ground Slots (GSs) and the annual throughput of container terminals expressed in Twenty-foot Equivalent Units (TEUs) have been used as the efficiency and performance measure for many years. The study in this thesis introduces appropriate container yard design layouts and provides a generic model for calculating the annual throughput for container terminals using semiautomated SC and RTG and automated and semi-automated RMG operating systems. The throughput model proposed in this study incorporates the dynamic nature, size, type and capacity of the automated container yard operating systems and the average dwell-times, transhipment ratio, accessibility and stacking height of the containers as the salient factors in determining a container terminal throughput. Further, this thesis analyses the concept of cost functions for container yard operating systems proposed. It develops a generic cost-based model that provides the basis for a pair-wise comparison, analysis and evaluation of the economic efficiency and effectiveness of automated and semi-automated container yard stacking cranes and helps to make rational decisions. This study proposes a Multiple Attribute Decision-Making (MADM) method for evaluating and selecting the best container yard operating system amongst alternatives by examining the most important operating criteria involved. The MADM method proposed enables a decision-maker to study complex problems and allows consideration of qualitative and qualitative attributes that are heterogeneous in nature. An Analytical Hierarchy Process (AHP) technique has been employed as a weighting method to solve the MADM problem. The AHP allows for the decomposition of decision problem into a hierarchical order and enables a pair-wise comparison of the attributes and alternatives. The results of the AHP analysis provide the basis for a pair-wise comparison, judgement and selection of the best automated or semi-automated container yard operating system.