只要关闭起大门,四合院内便形成一个封闭式的小环境。
This is from the Standard Course Book of HSK5, section 14.
What is the meaning of 起?
I am here:
只要(as long as)关闭(close)起(starts)大门(the big door).
But I am really perplexed since the 只要(as long as) has duration, while the 起(starts) happens once, so I cannot make it have sense.