Meaning of "by virtue of..."

Designed to resist storms by virtue of their immense weight, the oil platforms towed into the North Sea were the heaviest objects ever moved by human technology.

What does “by virtue of…” mean?


by virtue of smth means by means of smth

ok, but the sentence still doesn’t make sense to me…

The oil platforms were designed to resist storms and it’s their immense weight that makes them so resistant. In other words, they can resist storms because of their immense weight.