Barracks Removal

You can't remove barracks. You can disable barracks by clicking on province. Then click on barracks. Then disable barracks.

You can also go to the province list and click the barracks symbol there. The hint and "no entry" sign well show that it is disabled.

And note also >> even damaged barracks level 2 and 3 consume food and they can only be disabled in the province list, not in the province itself.

The same applies to damaged ports of Level 2 and 3.