Many of our clients find themselves in situations where their existing storage tanks have sunk below grade or have experience sever differential settlement, taking their tanks outside the allowance of API 653. When you or your client find themselves in a situation where a tank needs to be raised or leveled give us a call. Our tank repair team will evaluate your situation and develop a plan which will safely fix the problem.
Example of Settlement Experience by Tank
Differential settlement at the shell:
It is not uncommon for tanks to sink at the shell but maintain their elevation across the remainder of the floor. Advance Tank has the capability to come in and excavate the area running the circumference of the tank. We will then jack the tank bottom back to the appropriate elevation. Once the tank is back to the original elevation our crews will install aggregate or a new ring wall foundation in the settled area.
Differential settlement across the width of the tank:
If a tank experiences settlement on a slope the tank shell and roof structure can become unstable. When this type of settlement occurs it is critical to correct the problem. Advance Tank will jack the tank back to level. This can be done by the use of hydraulic jacks or air bags. Once the shell has been re-leveled our crews will enter the tank and install ports or couplings in the floor. Grout or slurry will then be pumped through the couplings into the voids under the tank. Our crews will then make all necessary adjustment to columns and roof structure.
Unfortunately, most terminals and refineries in the Unite States were built on poor soil. It was also a common practice to build welded steel tanks on grade. The end result for these tanks has been settlement, in some cases so extreme entire bottom courses have been abandoned. If your company finds itself with a tank that has settles several inches give us a call. The most common solution to settlement has been installing a double bottom and abandoning all the volume which is located below grade. However, in some cases loosing that storage volume is not an option. Advance Tank partners with companies who own equipment that can lift an entire tank. We team up with these companies to raise the tank back above grade. The tank must be jack and supported at an elevation where new material or a new foundation can be installed under the tank. Once soil modification or foundation installation is complete the tank will be lowered back to its new elevation.
Advance Tank has experience in retrofitting inappropriately sized foundations, or installing new ring wall foundation under existing tank. In many cases these new foundations are being required by local, state, and federal agencies who are requiring secondary containment in all storage tanks. Advance Tank has the capability of removing an existing floor, excavating all fill material, installing a new liner, cathodic protection, new fill material, and the new tank bottom. Advance Tank has performed this service for both the federal government and private industrial customers.