Abstract: A seismic brace having a brace arm for fastening to a support rod on one end and a structural portion of a building, on the other end, is attachable to the support rod without disconnecting it by a base bracket hinged to the brace arm and a locking bracket hinged to the brace arm or the base bracket to overlay the base bracket. Both the base bracket and locking bracket have a slot extending from an edge towards the middle with one slot offset form the other by ninety degrees (90.degree.).