The present invention relates to a device for the anchoring in rigid ground such as decks or floors made of concrete, asphalt, rock etc., for support posts for safety barriers and parapets, by means of bolts partly embedded in the ground and fixed to same by chemical or mechanical means, whose emergent part successively traverses the anchor plate of the post of the barrier, one or more washers and closure nuts which are what fix the bolt to the anchor plate. The washers present the capacity to behave as fusible elements which, in the event of a vertical load due to traction greater than a defined value, are deformed and traversed by the closure nut which, once released from the washer, traverses the corresponding hole of the anchor plate, which is of a size greater than that of the closure nut, with the union between the plate and bolt thus becoming decoupled.