Large-tonnage low-retraction pres-stress anchor and tightening device thereof

Abstract

The invention discloses a large-tonnage low-retraction pre-stress anchor. The large-tonnage low-retraction pre-stress anchor comprises a bearing plate, an anchor block and a bearing nut, wherein the anchor block is matched with the bearing nut in a threaded manner; the bearing nut is firmly adhered on the bearing plate; a protective cover is arranged on the bearing plate; the anchor block and the bearing nut are covered inside the protective cover; and the bearing plate is a steel plate. According to the large-tonnage low-retraction pre-stress anchor, the bearing plate adopts the steel plate after corrosion prevention and thermal treatment, and can improve rigidity characteristic of the bearing plate, thereby avoiding an occasion that the bearing plate is crushed by the supporting foot in a second large-tonnage tension process; simultaneously, the anchor is externally arranged on a reinforced concrete anchorage region, so that local weakening to the concrete section can be avoided by the anchor structure and the structural safety of the concrete anchorage region is ensured. The invention further discloses a tightening device for the anchor, and the supporting foot of the tightening device is of a sleeve structure, so that the contact area of the supporting foot and the bearing plate can be increased, the stress concentration is reduced, and the occasion that the bearing plate is crushed in the second large-tonnage tension process can be avoided.

Description

technical field [0001] The invention belongs to the technical field of prestressed anchorage, and in particular relates to a prestressed anchor with large tonnage and low retraction and a tensioning device thereof. Background technique [0002] At present, in the construction of cable-stayed bridges, many technical issues are involved in the anchorage of cable-stayed cables on reinforced concrete towers. The anchorage area of ​​the cable tower is an important force-bearing structure that transmits the cable force to the tower column evenly and safely, and is one of the most important force-bearing components of the cable-stayed bridge. Since the anchorage area of ​​the cable-stayed cable bears a strong concentrated load, the structure of the anchorage area is complex, and the structure under the load is in a complex stress state, applying horizontal prestress is the most commonly used treatment method, but the space of the anchorage area of ​​the cable tower is limited, and ...

AI Technical Summary

Problems solved by technology

[0005] However, this anchorage does not require improvement of the anchor backing plate. For small-tonnage prestressed beams, ordinary anchor backing plates can meet the requirements, but for large-tonnage prestressed beams, the nuts should be tightened in the secondary tension to achieve low return. When shrinkage is required, because the support foot at the front end of the jack is subjected to a large force, when it acts on the ordinary cast iron anchor plate, the anchor plate is often crushed, or the anchor tooth block concrete is crushed.

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