Storage tanks play a vital role in society and national life, in petrochemical, national defence, transportation and our daily life. Without storage tanks a lot of industries, especially the petrochemical enterprises, wouldn’t be able to produce regularly. 

The most widely used storage tanks are made out of steel which accounts for the largest area and the highest proportion of investment in oil depot construction projects. The technology and economic performance of storage tanks directly impacts the total cost, operating cost and capital cost of a project. 

Storage tank construction is dominated by two different methods for aboveground vertical tank construction:

• The traditional method (bottom to top)
• The jacking method (top to bottom)

The question is: which storage tank construction method is the most suited for your project? In this article we’ll give a brief description of each method and the advantages and disadvantages of each method.

 

The Traditional method

The traditional method for storage tank construction assembles each sheet of the tanks wall starting from the bottom ring of the tank, then each sheet is assembled one by one from the bottom to top until the tank is completely constructed. 

The process is as follows:

1. Bottom of tank is installed
2. First ring, the lowest, of the tank wall is installed
3. Second ring of the tank wall is installed, the third ring of…. etc.
4. Reinforcement ring is installed
5. Floating roof is installed
6. Accessories are installed

Advantages

• Easy to master
• Makes full use of large hoisting equipment
• Increase the depth of prefabrication
• Convenient for extension of automatic welding technology

Disadvantages

• Requires a larger site and scaffoldings
• Difficult to construct storage tanks due to technical difficulties, for example: high altitude work

 

The Jacking method

The jacking method works in the opposite direction, from top to bottom, by assembling the sheet of the top ring first, then lifting the assembled wall to assemble the lower wall, and continuing this process of lifting assembled walls until all of the tank wall is constructed.

There are several jacking methods for storage tank construction. The most common method using a hydraulic jacking system which we will describe below.

The process is as follows:

1. Bottom of tank is installed
2. Hydraulic jacking system is installed
3. Roof of the tank is installed
4. First ring (top) of the tank wall is assembled
5. First ring of the tank wall is lifted
6. Second ring of the tank wall is assembled
7. Second ring of the tank wall is lifted, repeat step 6-7 for all rings until the wall is fully assembled
8. Accessories are installed

Advantages

• Constructing the tank is short, effective and tank quality can easily be controlled
• Avoid risky high-altitude work where the whole installation process takes place on the ground without any scaffolding
• The activities of the storage tanks construction are larger, where the security can be better ensured
• Required hoisting equipment and construction tools are relatively more simple

Disadvantages

• Due to the fact that the jacking method lifts the tank, the higher the tank is, the more lifting power is required. Thus, this way of constructing storage and welded tanks is suitable to construct relatively small tanks.

 

Which construction method for building storage and welded tanks is the best?

Overall, the jacking method comes out on top. It is both economical and fast where all construction work is performed on the ground, ensuring high degree of safety and accuracy in the workmanship.  

We at Bygging-Uddemann offer one of the world’s leading steel tank manufacturing and construction methods based on the jacking method where it can be applied to different types of storage and welded tanks of all sizes. Contact us for more information or read more about our method here.