Container Yard Planning & Capacity Calculation | Equipment Solutions

To do container yard planning, many people's first reaction is to figure out how many boxes can be placed on a piece of land.However, in actual operation, it is often encountered that the theoretical capacity is enough, but the actual situation is blocked. The truck queues up, the containers are frequently reversed, the equipment cannot be turned around, the land and equipment are not put into less investment, but the throughput cannot go up.
The actual storage yard capacity is never simply divided by the area of a single box covers an area of, it and stacking height, box structure, equipment selection, operation channel, storage cycle, peak fluctuations are directly related.As a manufacturer of port yard equipment, Henan Mine Crane has come into contact with many projects that are full in planning stage and crowded in operation stage.This article explains the complete logic, core formula, influencing factors and equipment matching method of capacity calculation clearly, and helps the customers who build or expand the storage yard to make solid preliminary planning.

What is the container yard capacity

In short, container yard capacity refers to the number of containers or total TEU that can be stored at the same time in a site under the premise of safe and smooth operation, as well as the corresponding annual throughput capacity that can be carried.
The static capacity depends on the simultaneous storage capacity, and the dynamic annual throughput capacity shall be calculated in combination with the average storage period of containers.The basic algorithm commonly used in the industry is to multiply the number of ground container spaces by the average stacking height, and then multiply by the TEU conversion factor and the actual utilization rate to obtain the static container storage capacity; and then combine with the average stacking days to convert the annual processing capacity.
A lot of planning mistakes are based on 100% full load calculation, ignoring the passage, safety spacing, special box area, equipment operation space and operation buffer, and finally the actual usable capacity is far lower than the theoretical value.

Why is capacity planning important

The capacity of the storage yard directly determines the upper limit of the overall throughput of the wharf.If the configuration of quay crane, gate and truck is sufficient, the yard cannot be connected or rotated, and the whole link will be blocked in the middle.A complete container terminal capacity is the result of the matching of berth, yard and gate. It is useless to look at one item alone.
Capacity planning also directly determines equipment selection.Different handling equipment corresponds to a completely different stacking density, with RTG rubber-tyred gantry cranes having the highest stacking density, front cranes requiring more turning and working space, and straddle carriers lying in between.If the equipment is not selected correctly, either the land is wasted seriously, or the operation efficiency is not improved.
The hidden costs brought about by unreasonable planning are higher: the number of container dumping increases, the waiting time of the truck increases, the fuel consumption increases, the equipment idling increases, and the potential safety hazards brought about by the yard congestion are not small expenses in the long run.

Capacity Characteristics of Stockyard Corresponding to Different Equipments

Clear up a few core concepts before calculating

Before calculating the capacity, align a few basic concepts so that the result will not deviate too much.
TEU is also the standard container unit, 20 feet container is 1 TEU, 40 feet is 2 TEU, 45 feet is usually 2 TEU for planning conversion.The total TEU capacity of a storage yard varies significantly with the proportion of container types.
Ground slot refers to the position on the ground where a standard container can be placed.If the site is planned as per 40-foot container space, it shall be converted into unified TEU unit for calculation and then summarized.
Stacking height is how many layers can be stacked in the vertical direction. In the industry, 1-over-2 means stacking 3 layers high, and 1-over-4 means stacking 5 layers high.The higher the pile, the greater the capacity per unit area, but the probability of falling boxes will also increase accordingly.
The utilization ratio of the storage yard is the proportion of the theoretical capacity that can be used normally.In reality, it is impossible to fill up 100%, so the truck passage, equipment walking space, safety distance, refrigerator area, dangerous goods area, inspection area and operation buffer space shall be reserved.
Stacking period refers to the average number of days that the container stays in the yard from the arrival to the departure.The shorter the stockpiling period, the greater the annual throughput that can be supported by the same static capacity.

Calculation formula of basic capacity

The core formula for static yard capacity is not complicated:
Static storage capacity (TEU)= number of ground containers * average stacking height * TEU conversion factor * storage utilization
Take an intuitive example: a yard has 1000 ground container slots, 4 layers are stacked on average, the conversion factor of TEU is 1.6, and the actual utilization rate is calculated as 75%, so the static capacity is 1000 × 4 × 1.6 × 0.75 = 4800 TEU.
Among these parameters, stacking height and utilization rate are the most likely to be overestimated.The stacking height shall match the equipment capacity, and the utilization rate shall be determined in combination with the functional partition of the storage yard. The more complex the function of the storage yard, the lower the actual utilization rate.

The conversion of annual throughput capacity also has the corresponding formula:

In the yard throughput capacity = static capacity x 365 present the average storage period
Again, if the average storage period is 6 days, the throughput is 4800 x 365/6 = 292000 TEU/year.
This also shows that shortening the storage period of containers is an effective way to improve the throughput capacity without expanding the land.
The reverse can also be extrapolated: given the annual throughput target, calculate how many ground slots are needed.The formula is:
The number of ground slots required = TEU amount x average storage period x peak factor present 365 present average stack height present utilization rate present TEU coefficient
For example, the annual target is 200,000 TEU, the average stacking time is 7 days, the peak value coefficient is 1.2, the stacking is 4 layers, the utilization rate is 75%, and the TEU coefficient is 1.6, so about 960 ground container slots are needed.

Core Factors Affecting Yard Capacity

Calculate the theoretical value, but also combined with the actual situation to do correction, there are several factors that have the greatest influence.
The first is the total area and layout of the yard.In the total available land, the box area only accounts for a part, and the area of truck collection road, equipment walking area, fire escape, maintenance site, gate entrance and exit, and railway connection area shall be deducted.The land utilization rate varies greatly with the arrangement of the box area.
The second is the box structure.The proportion of 20 feet, 40 feet, empty containers, refrigerated containers, dangerous goods containers, transit containers, will change the actual capacity.The refrigerator shall be connected with electricity, maintenance passage shall be reserved, and the dangerous goods box shall be kept with safe spacing, which occupy more space than the ordinary dry box.
The effects of the stockpiling period are most easily overlooked.The same static capacity, storage period of 3 days and storage period of 10 days, the annual throughput can be more than three times.Different business modes lead to great differences in stacking period, with short stacking period at transit port and long stacking period at inland bonded yard.
Stacking height is not the higher the better.The higher the pile, the greater the theoretical capacity, but the number of cases will increase, the single box operation time becomes longer, the actual operation efficiency may decline.To match the equipment capacity, box area management level.
The impact of equipment type has also been mentioned above. RTG and RMG have high density, and the front crane and forklift require large working space.The same piece of land, choose different equipment, available capacity and operating efficiency are completely different.
There are also peaks and seasonal fluctuations.It is not only calculated according to the average daily quantity. In peak season, when ships arrive at the port intensively and the suitcase is delayed, the pressure on the storage yard will increase sharply.Generally, the peak coefficient of 1.1 to 1.5 shall be reserved, otherwise it is easy to block during peak period.

Common Calculation Mistakes

Planning stage is the most easy to step on a few pit, a lot of yard are met.
Calculating capacity at 100% utilization is the most common mistake.It's really full, vehicles can't get in, equipment can't turn on, normal operation can't be carried out at all, which is equivalent to man-made congestion.
Only static storage capacity is calculated, and the impact of storage period on throughput is not considered.Two static capacity of the same yard, storage period is different, the annual processing capacity.
Ignore equipment turning radius and working space.Especially for the storage yard with front crane, there is not enough turning depth and operation depth left, the equipment cannot be used, and the actual available container spaces are much less than planned.
Do not distinguish between box type, according to the ordinary dry box.There are a large number of refrigerated containers, dangerous goods container yard, but also according to the ordinary standard calculation, the final capacity is certainly not enough.
It's just storage, not circulation.The storage yard shall be matched with the quayside crane capacity, gate capacity, truck capacity and equipment operation efficiency, and it is meaningless to look at the number of containers stored.

how to change that capacity of storage yard by equipment selection

Different loading and unloading equipment, the capacity of the yard to shape the logic is completely different.
The front crane is suitable for small and medium-sized storage yards, inland storage yards and railway stations, with strong flexibility and low investment, but it needs more space for driving and turning, and the storage density is not as good as that of the gantry crane system.
RTG rubber-tyred gantry crane is suitable for high-density container area operation of medium and large storage yards, with neat stacking and high density, which is the mainstream choice of large terminals, but it needs regular container area layout and higher initial investment.
RMG rail-mounted gantry crane has higher density and low electrification operation cost, which is suitable for railway station and automatic storage yard. The disadvantages are fixed track, poor flexibility and large investment in early infrastructure.
Straddle carrier gives attention to both transfer and stacking, flexible operation, suitable for the need to transfer the wharf, but the stacking density than gantry crane equipment.
Special equipment for empty containers can be stacked very high, and special equipment for empty container yard can greatly improve storage density.

Method for increasing capacity without expanding land

Land tight yard, don't rush to expansion, several directions can tap the potential.
The most effective way is to shorten the stacking period. By means of booking containers, quick customs clearance, optimizing truck scheduling and electronic container placement, the containers can be transferred faster, and more containers can be handled in the same site.
Optimize the layout of the yard, adjust the arrangement of container areas, lane direction and position of special container areas, reduce cross moving lines and invalid space, and squeeze out a lot of available capacity.
Replace higher density work equipment, such as upgrading from a front hoist to an RTG, increasing stacking height and box area density, and increasing storage capacity on existing sites.
Empty container and heavy container partition management, empty container with special equipment stack is higher, heavy container area optimization box logic, each play a maximum efficiency.
Make good use of the terminal operating system TOS, reduce unnecessary box turnover, improve the accuracy of box position, and also improve the effective capacity and operation efficiency in a disguised form.
Finally, we must leave enough peak buffer, do not use up the site according to the average daily volume, otherwise the peak season will be congested.

common problem

What is the formula for calculating the capacity of the container yard?

Static capacity = number of containers on the ground × average stacking height × TEU conversion factor × yard utilization rate; annual throughput capacity = static capacity × 365 ÷ average stacking period.

What is the difference between static capacity and throughput?

Static capacity is how many containers can be stored at the same time, and throughput capacity is how many containers can be handled in a year, and the latter is directly related to container residence time.

Yard utilization rate generally take how much more reasonable?

Planning is not calculated at 100%, to set aside lanes, equipment operation space, safety zone and peak buffer, most of the yard between 65% and 80%, the more complex the function value is lower.

What equipment can lead to higher yard capacity?

RTG and RMG gantry cranes have a higher stacking density; front cranes are more flexible but require more working space.

How to improve the throughput capacity of the storage yard without expansion?

Shortening the stacking period, optimizing the layout, improving the stacking density, upgrading the equipment and optimizing the management of the box area can improve the throughput capacity on the existing land.

epilogue

It is not as simple as setting a formula to calculate the capacity of container yard clearly, but comprehensively judge in combination with many factors such as container type, equipment, stacking period, peak value, moving line, etc.Reasonable planning can not only improve the land utilization rate, but also reduce the dumping and congestion, so that the equipment and site can play their due value.

Customize Your Solution

As a professional supplier of port yard equipment, Henan Mine Crane can provide the whole process service from yard planning, equipment selection to scheme implementation.If you are planning to build a new storage yard or evaluating the capacity expansion potential of the existing storage yard, you can send us the site area, annual TEU target, average storage period, box structure and intended equipment, and the engineering team will help you calculate the reasonable capacity configuration and recommend the matching handling equipment scheme