Well, they were forced into Tartarus.
And amongst the foremost Kottos (Cottus) and Briareos (Briareus) and Gyes insatiate for war raised fierce fighting : three hundred rocks, one upon another, they launched from their strong hands and overshadowed the Titanes with their missiles, and buried them beneath the wide-pathed earth, and bound them in bitter chains when they had conquered them by their strength for all their great spirit, as far beneath the earth to Tartaros . . . There by the counsel of Zeus who drives the clouds the Titan gods are hidden under misty gloom, in a dank place where are the ends of the huge earth. And they may not go out; for Poseidon fixed gates of bronze upon it, and a wall runs all round it on every side.There [the Hekatonkheires] Gyes and Kottos and great-souled Obriareus live, trusty warders of Zeus who holds the aegis . . . But when Zeus had driven the Titanes from heaven [then Gaia bore the monstrous giant Typhoeus to oppose Zeus]."
So the hundred hand people scooped up the Titans and buried them in Tartarus, and with the help of a bronze gate, guarded them forever until they were released.
Theoi says
Many human generations later, Zeus released Kronos and his brothers from this prison, and made the old Titan king of the Elysian Islands, home of the blessed dead.