Completes building site at college (4,2)

I believe the answer is:

ties up

'completes' is the definition.

'building site at college' is the wordplay.
'building' indicates an anagram.
'at college' becomes 'up'.
'site' with letters rearranged gives 'ties'.
'ties'+'up'='TIES UP'

(Another definition for ties up that I've seen is " Tethers".)

I've seen this clue in The Guardian.

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