Retard-bonded prestressed steel bar

Abstract

A retard-bonded prestressed steel bar comprises two fixing plates, two tensioning plates and a plurality of prestressed steel bars, the two fixing plates are arranged at the two ends of the prestressed steel bar respectively, and the two tensioning plates are arranged at the two ends of the prestressed steel bar respectively; a plurality of through holes are formed in each fixing plate and each tensioning plate, the end part of each prestressed steel bar is of a stud structure, and the stud structures respectively penetrate into the through holes of the fixing plates and the through holes of the tensioning plates; in conclusion, the prestressed steel bars are arranged between the fixing plates, force can be applied to all the prestressed steel bars at the same time by applying force to the tensioning plates, balance of tension is guaranteed, in addition, the prestressed steel bars can be effectively protected through the protective sleeves, the slow-bonding layers on the outer sides are prevented from being damaged, the use effect is good, and the service life of the prestressed steel bars is prolonged. By arranging the springs, concrete stones can be prevented from entering or approaching the prestressed steel bar to damage the protective layer, and large friction caused by direct contact is also avoided; the overall structural design is reasonable, the curing effect is good, toughness is high, and use is safe.

Description

Technical Field

[0001] The utility model belongs to the technical field of engineering construction, and in particular relates to a slow-bonding prestressed steel rod. Background Art

[0002] At present, the domestic prestressed system can be divided into three forms according to the construction method: unbonded prestressed system, bonded prestressed system and slow-bonded prestressed system. Among them, the unbonded prestressed system has the advantages of flexible and convenient reinforcement, and does not require cumbersome and complicated construction procedures such as reserved channels and grouting. It has been widely valued by the engineering community and has been widely used since its appearance. However, since the prestress of unbonded prestressed tendons is almost equal everywhere during work, it is easy to cause fatigue problems of prestressed tendons and anchors. At the same time, there are also shortcomings such as small number and large width of concrete cracks in the tension zone, which easily cause corrosion of prestressed tendons and low strength utilization. More importantly, once the steel rod breaks, it is very likely to fly out of the track plate through the lubrication between the anti-corrosion grease applied on its surface and the sheath, causing casualties.

[0003] The bonded prestressed system overcomes the problems and shortcomings of the unbonded prestressed system in operation, but the reserved channels required by the construction process are large, and there is a problem of incomplete grouting. The shrinkage of concrete after grouting will cause cracks, which will cause corrosion and failure of the steel bars. The expansion coefficient of concrete with the addition of expansion agent is difficult to control, and it is easy to produce expansion stress, causing early cracks in the concrete.

[0004] The slow-bond prestressing technology is mainly used in steel strand products. From a theoretical analysis, due to the special structural form of the steel strand, through theoretical calculation and design of a matching outer protective sleeve, the bond strength between the concrete and the sleeve, and between the sleeve and the steel strand can meet the design and use requirements, which can meet the concrete engineering fields such as municipal highway bridges and railway bridges that are subjected to large dynamic loads and require periodic repeated fatigue loads. However, in actual engineering applications, the slow-bond prestressing system is constructed in the form of non-bonding construction, which has a long curing cycle, uncertain curing effect, cannot be stored for a long time, and cannot be artificially controlled. Therefore, this method is greatly affected by the product supply cycle. Utility Model Content

[0005] The utility model aims to provide a slow-bonding prestressed steel rod, which solves the technical problem of uncertain curing effect of a slow-bonding prestressed system in the prior art.

[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0007] A slow-bonding prestressed steel bar comprises two fixing plates, two tensioning plates and a plurality of prestressed steel bars, wherein the two fixing plates are respectively arranged at two ends of the prestressed steel bar, and the two tensioning plates are respectively arranged at two ends of the prestressed steel bar;

[0008] Each fixed plate and tensioning plate is provided with a number of through holes, and the end of the prestressed steel rod is a stud structure, which is respectively inserted into the through holes of the fixed plate and the tensioning plate. An inner nut and an outer nut are also threadedly installed on the stud structure, the inner nut is located between the fixed plate and the tensioning plate, and the outer nut is located at the end of the stud structure.

[0009] Furthermore, springs are respectively arranged at both ends of the prestressed steel rod, and the springs are connected to two fixed plates.

[0010] Furthermore, the main body of the prestressed steel bar is threaded steel.

[0011] Furthermore, a protective sleeve is arranged outside the main body of the prestressed steel rod, and the protective sleeve is made of extruded polyethylene resin.

[0012] Furthermore, the outer wall of the protective sleeve has protruding transverse ribs.

[0013] Compared with the prior art, the utility model has the following beneficial effects: several prestressed steel bars of the utility model are arranged between the fixed plates, and force can be applied to all the prestressed steel bars at the same time by applying force to the tensioning plate, thereby ensuring the balance of tension; in addition, the protective cover can effectively protect the prestressed steel bars to prevent damage to the outer slow-bonding layer, and the use effect is good; the setting of the spring can prevent concrete stones from entering or approaching the prestressed steel bars to damage the protective layer, and also avoid direct contact to produce greater friction; the overall structural design is reasonable, the curing effect is good, the toughness is high, and it is safe to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 It is a structural schematic diagram of a slow-bonding prestressed steel bar;

[0016] Figure 2 A schematic diagram of the structure of the protective cover. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] The present invention is further described in detail below in conjunction with the embodiments.

[0019] like Figure 1 As shown, a specific embodiment of a slow-bonding prestressed steel bar provided by the utility model is as follows:

[0020] A slow-bonding prestressed steel bar comprises two fixing plates 1, two tensioning plates 2 and a plurality of prestressed steel bars 3, wherein the two fixing plates 1 are respectively arranged at both ends of the prestressed steel bars 3, and the two tensioning plates 2 are respectively arranged at both ends of the prestressed steel bars 3;

[0021] A plurality of through holes are provided on each of the fixing plate 1 and the tensioning plate 2. The end of the prestressed steel rod 3 is a stud structure, which is respectively inserted into the through holes of the fixing plate 1 and the tensioning plate 2. An inner nut 4 and an outer nut 5 are also threadedly installed on the stud structure. The inner nut 4 is located between the fixing plate 1 and the tensioning plate 2, and the outer nut 5 is located at the end of the stud structure.

[0022] Springs 6 are respectively provided at both ends of the prestressed steel rod 3 , and the springs 6 are connected to the two fixing plates 1 .

[0023] The prestressed steel rod 3 of this embodiment adopts the high-strength and low-relaxation steel rod required by "Steel Rod for Prestressed Concrete" (GB / T 5223.3-2017). The prestressed steel rod 3 is obtained by quenching and tempering after cold working of hot-rolled wire rod. The stud structure at its end is formed by rolling. The thread diameter is 16.026mm, the pitch is 1.5mm, and the thread tolerance zone adopts 6H / 6g combination. The basic size and tolerance shall comply with the relevant requirements of CB / T196 "Basic Dimensions of Ordinary Threads" and GB / T197 "Ordinary Thread Tolerances". Then, the main body of the prestressed steel rod 3 is oiled, a slow-adhesive agent is applied, and a protective cover 7 is put on the outer edge of the combination. Figure 2 As shown, the protective cover 7 is made of extruded polyethylene resin, and the outer wall of the protective cover 7 has protruding transverse ribs 8.

[0024] During installation, the fixed plate 1 is pre-embedded and installed on the supporting formwork, and then the tensioning plate 2 at both ends of the prestressed steel rod 3 is pulled by a tensioning machine. The spring 6 on the fixed plate 1 can prevent concrete stones from entering or approaching the prestressed steel rod 3 to damage the protective layer, and also avoid direct contact to produce greater friction.

[0025] It should be noted that, in this article, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0026] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A slow-bonding prestressed steel bar, characterized in that: It includes two fixed plates, two tensioning plates and a plurality of prestressed steel bars, wherein the two fixed plates are respectively arranged at both ends of the prestressed steel bars, and the two tensioning plates are respectively arranged at both ends of the prestressed steel bars; Each fixed plate and tensioning plate is provided with a number of through holes, and the end of the prestressed steel rod is a stud structure, which is respectively inserted into the through holes of the fixed plate and the tensioning plate. An inner nut and an outer nut are also threadedly installed on the stud structure, the inner nut is located between the fixed plate and the tensioning plate, and the outer nut is located at the end of the stud structure.

2. A slow-bonding prestressed steel bar according to claim 1, characterized in that: Springs are respectively arranged at both ends of the prestressed steel rod, and the springs are connected to two fixed plates.

3. The slow-bonding prestressed steel bar according to claim 1, characterized in that: The main body of the prestressed steel bar is threaded steel.

4. A slow-bonding prestressed steel bar according to claim 3, characterized in that: A protective sleeve is arranged outside the main body of the prestressed steel rod, and the protective sleeve is made of extruded polyethylene resin.

5. A slow-bonding prestressed steel bar according to claim 4, characterized in that: The outer wall of the protective sleeve is provided with protruding transverse ribs.

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