Pre-stress height-limiting portal frame

The utility model relates to a pre-stress height-limiting portal frame. The height-limiting portal frame can effectively guarantee safety of vehicles and personnel and has the advantages of being simple, firm in structure and convenient to maintain. According to the technical scheme, the pre-stress height-limiting portal frame comprises a height-limiting rod and two stand columns, wherein the height-limiting rod horizontally stretches over a road, and the two stand columns are vertically fixed to the two sides of the road and used for supporting the two ends of the height-limiting rod respectively. The pre-stress height-limiting portal frame is characterized in that a supporting plate is fixed to the top of each stand column and extends horizontally in the passage direction of the road; the height-limiting rod can be horizontally placed on the supporting plates in a sliding mode, and the two ends of the height-limiting rod are connected with the tops of the stand columns through elastic ropes.