The earliest tanks we jacked were located in the Rotterdam, Netherlands, harbor area. The soft soil conditions in the river delta resulted in settlements due to a load of filled storage tanks. The jacking projects in the years following spread to areas with similar soil conditions throughout Europe, the Gulf Coast, the Mississippi River Delta and Canada.
Nowadays, tank settlement is not the only reason for tank jacking. A combination of repairs and tank improvements is presently the basis for the jacking of tanks. Another important reason for tank jacking is aging. Many tanks were constructed in the growth decennia of the 1960s and 1970s. In 50 years’ time, tank bottoms have lost their thickness in such a way that replacement is necessary.
Environmental requirements have changed significantly, adding special applications to ensure tank tightness and expand their lifetimes. Secondary containment is required by authorities at many locations for new tank construction. Under older tanks, liners are installed during repairs to prevent ground pollution in case of leaks.
When is tank jacking most profitable?
In parts of the world, the jacking of tanks is seen as an additional cost on top of repair works. Unfortunately, this view is very limited, only seeing direct costs filtered from quotations.
The combination of several types of repairs and installations of applications, together with the increased quality of the repairs and reduced repair time, makes the jacking technique most valuable to the total project and long-term tank usage.
The following repair work can or should be combined to achieve optimum results:
- Foundation repairs consisting of replacement of old foundation materials for new, more suitable materials such as crushed stone ring walks or other aggregate materials, combined with releveling of the tank foundation.
- Replacement or removal of damaged concrete ring walls, or installation of new ones.
- Removal of pollution in case of leakages.
- Installation of secondary containment liners.
- Application of coatings at the underside of the tank bottom.
- Replacement of entire tank bottoms or replacement of annular plates where the new plates can be installed in the “as built” shape. (Letterbox methods such as butt-welds often don’t allow for releveling of the foundation and limit the quality of welding.)
A combination of the above works results in win-win situations regarding time, quality, and safety.
Tank relocations
Besides tank repairs, the jacking technique also allows for easy methods of tank relocation. Tanks with diameters up to 230 feet have been shifted for reasons such as a newly designed plot plan, a new owner on a different site or storage of a different product. Examples are available of temporarily shifting a tank for installation of a piled foundation or for the removal of polluted soil underneath the tank. For each type of relocation, different techniques are developed, ranging from skid tracks, modular trailers and floating barges to floating cranes.
Solutions for the long term
Participation in a repair program can be a first and important step toward the most reliable repair method. With the experience of more than 10,000 tanks being jacked, there are solutions for any problem with a storage tank. In the jacking business, quality, scheduling, and safety are the key elements for the petrochemical industry.
For more information, visit www.Verwater.com or call (281) 549-6685.
