Operations Systems of Container Terminals: A Compendious Overview

This section contains an overview of the different functional areas of a marine container terminal and a summary of the main types of container handling systems. The main advantages and disadvantages of each type of handling system are also summarized without focusing on technical details. 2.1 Functional Areas of Terminal Operations As every other terminal, a container terminal is a complex system that functions only efficiently when its layout is designed in such a way that the loading and discharging process of vessels runs smoothly. A container terminal consists of at least three operational areas: 1. operational area between quay wall and container yard (apron or the area just behind the berth front) 2. container yard (terminal storage = stacking area) 3. terminal area of landside operations (including the gate, parking, office buildings, customs facilities, container freight station with an area for stuffing and stripping, empty container storage, container maintenance and repair area etc.) The importance of the container freight station has decreased within the past decades as more and more containers are sent directly from the originator to the addressee without being transhipped. Nevertheless, a lot of terminals are provided with a container freight station for storage purposes. Figure 2.1 shows the schematic layout of Birgitt Brinkmann Institute for Sustainable Use of Natural Resources and Infrastructure Development Leuphana University Lüneburg Herbert-Meyer-Straße 7, 29556 Suderburg, Germany email: [email protected] 25 J. W. Böse (ed.), Handbook of Terminal Planning, Operations Research/Computer Science Interfaces Series 49, DOI 10.1007/978-1-4419-8408-1_2, © Springer Science+Business Media, LLC 2011 26 Birgitt Brinkmann a container terminal with the different operational areas. The transport between the areas is carried out using handling equipment for horizontal container transport. The layout and choice of equipment for the above mentioned areas and their interfaces depend on, amongst others, the • number of containers to be handled, • available area and • mode of hinterland transport. The combination of terminal equipment used • at the vessel, • for transport tasks between quay and stacking yard (or vice versa), • for container stacking, • for transport from stacking yard to and from the landside operation area and • for landside operation itself is called operations system. Fig. 2.1 General layout of a container terminal (see Brinkmann (2005)) Independent from the selected terminal operations system, specific processes are performed on the different areas. 2 Operations Systems of Container Terminals 27 On the apron area the ship-to-shore operations (loading and discharging of vessels) are carried out. In the beginning of the container shipping the cargo handling on this area was mainly carried out with on-board lifting gear of the vessels or a regular quay crane. Nowadays this type of handling is only used on terminals with a comparatively low container throughput. On medium and large sized terminals the ship-to-shore handling of containers is usually carried out with gantry cranes specialized in this purpose. Container vessels are the only ships that can be loaded and discharged at the same time. The Ship-To-Shore gantry crane (so-called “STS crane”) discharges a container moving landwards and on its way back loads a container on to the vessel. This handling procedure requires good planning of the terminal equipment for the container delivery as well as for the container stacking in the yard and on the vessel. Landwards, the full container yard borders on the apron, used for • storing inbound (discharged from vessels) and outbound (to be loaded on vessels) container as well as for • storing export containers delivered by train or truck, and forwarding import container to these modes of transport. These operations usually do not happen at the same time. Therefore, the container yard is an intermediate storage facility, in which the containers remain from a couple of hours to some weeks (container dwell time = containers in the same position or area during this period of time, e.g. within the terminal area). There are different possibilities for the layout of this intermediate storage area (= stacking yard). If the stacking area is a compact, low ground area consuming stack without spacing, it is called block stack (see Figure 2.2; HHLA (2010)). In this case, yard gantry cranes are used for the stacking of containers being delivered by terminal equipment of horizontal transport. An alternative is the linear stack (see Figure 2.3) where the containers are stacked by Straddle Carriers (SC). This type of stacking requires spacing between the container rows and relatively wide terminal roads. Export and import containers are segregated within the yard area), piled up to 4 containers high and (relating to import boxes) pre-sorted for the different hinterland transport modes. The third rarely applied stacking alternative is the high-bay racking, used for terminals with high throughput requirements but very small available area. An example is Hong Kong with high-bay racks up to 12 container tiers. The configuration of the area for landside operation, as third main functional area of container terminals, is determined by the hinterland transport modes or related interfaces, respectively. In case of predominant truck operations, this functional area is often integrated in the yard area. The trucks are loaded and unloaded on dedicated spaces at the end of the stacking yard or in the middle of the yard, e.g. by SCs or yard cranes. In case of railway transport the loading/unloading should take place outside the stacking area to avoid the crossing of rail tracks by the yard equipment. This would increase the terminal efficiency and performance as well as the safety on the terminal. The loading/unloading is carried out directly by the yard equipment or by gantry cranes being combined with appropriate vehicles for horizontal transport between railway station and terminal yard. 28 Birgitt Brinkmann Fig. 2.2 Block stacking Fig. 2.3 Linear stacking As only a traveling vessel makes money, the berthing time at the terminal quay wall should be as short as possible. First and foremost this can be achieved by a fast loading / discharging process of the vessel. To ensure this, the operational areas have to be tuned to each other. The length of a container terminal depends on the planned number of berths and the length of the design vessel as well as local restrictions (e.g. given geographic conditions). The (minimum) depth of the terminal depends on the operations system. The available area is a crucial factor for its selection. As a guide value, 600m–800m should be appropriate for new constructions of terminals. The remainder of this paper is organized as follows. Section 2.2.1 provides a brief overview of common equipment types and meaningful factors for equipment choice. In Section 2.2.2 to 2.2.5, various operations systems are introduced regarding their use of handling equipment for container stacking and transport in the operational terminal areas mentioned above. Additionally, the main operational and economic 2 Operations Systems of Container Terminals 29 advantages and disadvantages are outlined system-related. Lastly, Section 2.3 concludes the paper with an overview of functional system capabilities. 2.2 Operations Systems 2.2.1 Determinants of Operations System Choice To design and operate a successful container terminal is a challenging task with the objective to decrease the cost of operation while at the same time service quality and effectiveness of operation have to be increased. The new large container terminals being under construction, the ones already being designed and the future ones are ambitious projects (due to complexity and given economic/capacity requirements) and will challenge the terminal operators to further increase the efficiency and/or performance of loading/discharging processes. To achieve this, not only larger and faster STS cranes are required but also logistic capabilities of horizontal transport equipment to cope with augmentation of STS cranes. Therefore, the right selection of the operations system is a key factor to a successful terminal. The decision for an operations system depends, inter alia, on the following factors: • size of vessels • traffic forecast (annual container volume) • container volume in peak hours • available land area • required stacking density of the containers per ha (configuration of stacking yard) • cost structure (wages, financial facilities, dues) • aimed STS productivity (i.e. TEU / crane / hour) • geographic restrictions of the terminal area • contingent restrictions due to soil conditions • environmental impacts like wind, ice, noise, light and snow • mean dwell time of containers in the stacking yard • TEU factor (e.g. 1,6 implies 60% of all containers are 40 ft long) • percentage of reefer containers • percentage of empty containers (short: MTs) • percentage of LCL (Less than Container Load) • the connections to the hinterland transport modes road, railway and inland waterways The number of determinants shows that there is no “general ideal” container terminal. The usual equipment to fulfil the tasks in the three mentioned functional terminal areas (see Section 2.1) are: • quay cranes at the vessel: