The test was conducted to find out the impact of an internal overpressure in the tank and whether the wall/floor joint failed before the roof/curb joint occurred.
AMEC wanted to check if any such failure would lead to condensate remaining within the storage tank and not start a spillage.
The result of the test would confirm if works to the frangibility of the roof joint is required further.
The structural FE analysis was conducted by IDAC in two phases – linear buckling test to assess the buckling modes and critical buckling pressure, and non-linear buckling test to find the exact results during the process.
Non-linear analysis calculated a more precise critical buckling pressure and a safe pressure where the plastic strain was less than 10% and proved that the tank could withstand the critical buckling pressure safely.
During the analysis, the top and bottom welds were the most important welds in the tank, while the roof weld was the first area to withstand plastic strain greater than 10%.
The analysis concluded that first the roof would fail at the side which was welded to the curb bar, and the failure would then proceed through the thickness of the weld.
AMEC was satisfied with the test result as it proved that condensate storage tank would fail first at the roof/curb joint to allow gases to escape rather than any of the condensate.
