There is some speculation about what Nehemiah means with that phrase, with a consensus suggesting this refers to a fortress protecting the northern access to the city. Wherever its location, its gates had been burned and so new beams were needed. This, of course, would be true for more of the city gates.
8 and a letter to Asaph, the keeper of the king’s forest, that he may give me timber to make beams for the gates of the fortress of the temple, and for the wall of the city, and for the house that I shall occupy.” And the king granted me what I asked, for the good hand of my God was upon me.