Tag
#lng
5 topics across all disciplines.
What cold does to concrete
Concrete gets stronger as it gets colder, which is the most misleading fact in cryogenic civil engineering. Strength is not the governing property — contraction, brittleness and the loss of toughness in the reinforcement are, and all three move the wrong way.
LNG tanks: single, double and full containment
What the containment categories actually mean, which parts of a full containment tank are the civil engineer's and which are not, and why the outer concrete wall is a structure that has to work twice — once every day, and once in a condition that should never happen.
LNG tank foundations and base mats
A storage tank is the most unforgiving foundation problem on a plant: enormous load, applied uniformly, over a circle, with a settlement tolerance measured in millimetres. Here is why the piles are there, why the slab is usually off the ground, and what the hydrotest is really proving.
Frost heave and sub-soil heating
Frost heave is not water expanding by nine per cent. It is ice lenses growing by sucking water towards the freezing front, which is why heave can be hundreds of millimetres and why silt is far more dangerous than clay. Under a cryogenic tank the freezing front never goes away.
Post-tensioned containment walls
An LNG outer tank wall has to hold a column of liquid against hoop tension that ordinary reinforced concrete would crack under. Prestressing puts the wall into permanent compression so it never cracks through, and the whole design turns on keeping that compression for forty years.