CN113084998A

CN113084998A - Pre-tensioning method prestressed reinforcement tension-reducing member

Info

Publication number: CN113084998A
Application number: CN202110389282.9A
Authority: CN
Inventors: 范宗帅; 敖卫; 杨磊; 赵伟; 徐佳; 宋凯新; 冯西龙; 曹明歌; 余凌杰
Original assignee: China Construction Third Engineering Bureau Co Ltd
Current assignee: China Construction Third Bureau Group Beijing Co ltd
Priority date: 2021-04-12
Filing date: 2021-04-12
Publication date: 2021-07-09

Abstract

The invention discloses a pretensioned prestressing reinforcement tension-relieving member, which comprises a large slide block, a middle slide block, a small slide block, a middle slide block and a limit bolt rod; the large, medium and small cross sections are the same and are composed of isosceles trapezoids and rectangles; the sum of the height of the middle bearing plate and the height of the small bearing plate is equal to the height of the large bearing plate; the large, middle and small bearing plates are provided with first round holes; the cross sections of the middle and small sliding blocks are the same and are isosceles trapezoid cylinders; the height of the middle slide block and the height of the small slide block are higher than that of the large bearing plate; second round holes are formed in the middle sliding block and the small sliding block; the limiting bolt rod penetrates through the second round hole. The invention has simple structure, can conveniently achieve the slow tension of the prestressed rib, avoid the hidden danger of the component quality and save materials. Not only reduces the prestressed tendon waste materials, but also achieves the effect of slow tension, and does not damage the member concrete. The invention is convenient to install and disassemble, does not increase extra labor cost and can be used in a turnover way.

Description

Pre-tensioning method prestressed reinforcement tension-reducing member

Technical Field

The invention belongs to the field of buildings, and particularly relates to a pretensioned prestressing reinforcement tension-reducing member.

Background

The pretensioned prestressing tendons with bonded prestressing elements are released after concrete is poured and the prestressing is transferred by the bond force between the prestressing tendons and the concrete. At present, the prestressed components manufactured by component factories mostly adopt the following two prestressed tendon relaxation methods: the first method adopts a hydraulic press for slow tensioning, namely the effect of slow tensioning of the prestressed tendon is achieved through hydraulic top oil return, the method can not cause the prestressed tendon to impact concrete at the end part of the member, but the method needs a special mold and requires about 2m of buffer distance for each tensioning, so about 2m of prestressed tendon needs to be wasted, and more materials are wasted for the prestressed members produced in batches; the second method is to directly cut off the exposed prestressed tendons at the end parts by gas cutting (see figure 8), which does not waste materials but generates larger instantaneous impact force on the concrete at the end parts of the members due to the direct cutting of the prestressed tendons in a tension state, so that the risk of cracking of the concrete at the end parts of the members exists and further the quality of the members is influenced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a pretensioned prestressing reinforcement tension member.

The technical scheme of the invention is summarized as follows:

the pretensioning prestressed reinforcement slow-tension member comprises a large bearing plate 1, a middle bearing plate 2, a small bearing plate 3, a middle sliding block 4, a small sliding block 5 and a limit bolt rod 6; the cross section of the large bearing plate 1 consists of an isosceles trapezoid and a rectangle; the cross sections of the middle bearing plate and the small bearing plate are the same as the cross section of the large bearing plate; the height of the large bearing plate is sequentially greater than that of the middle bearing plate and that of the small bearing plate, and the sum of the height of the middle bearing plate and that of the small bearing plate is equal to that of the large bearing plate; the large bearing plate 1, the middle bearing plate 2 and the small bearing plate 3 are provided with first round holes 7; the middle slide block 4 is a cylinder with an isosceles trapezoid cross section; the cross section of the small sliding block 5 is the same as that of the middle sliding block; the height of the middle sliding block is greater than that of the small sliding block, and the height of the middle sliding block and that of the small sliding block are greater than that of the large bearing plate; second round holes 8 are formed in the middle sliding block and the small sliding block; the limiting bolt rod 6 penetrates through the second round hole; the isosceles trapezoid base angle beta of the cross section of the middle slide block 4 and the isosceles trapezoid base angle alpha of the cross section of the large bearing plate 1 form a complementary angle.

The invention has the advantages that:

the invention has simple structure, can conveniently achieve the effect of slowly tensioning the prestressed rib by using the member, avoids the hidden trouble of member quality and saves materials. Not only reduces the prestressed tendon waste materials, but also achieves the effect of slow tension, and does not damage the member concrete. The invention has convenient assembly and disassembly without increasing additional labor cost, simultaneously, the cost of each set of components is about 2000 yuan by taking the prestressed double T-shaped plate as an example, and the prestressed double T-shaped plate can be used circularly and has obvious economic and social benefits.

Drawings

FIG. 1 is a schematic diagram of a large pressure bearing plate, wherein A is a front view; b is a top view;

fig. 2 is a schematic structural view of a small pressure bearing plate, wherein a is a front view; b is a top view;

FIG. 3 is a schematic diagram of a structure of a middle bearing plate, wherein A is a front view; b is a top view;

FIG. 4 is a schematic diagram of a middle slider structure, wherein A is a front view; b is a top view;

FIG. 5 is a schematic view of a small slider structure, wherein A is a front view; b is a top view;

fig. 6 is a schematic view of a pretensioned prestressing reinforcement member according to the present invention.

Fig. 7 is a schematic view of the connection of the pretensioned prestressed reinforcement unit of the present invention with the pedestal steel plate and the prestressed reinforcement.

Fig. 8 is a schematic view of a method for releasing tension of a prestressed reinforcement in the prior art.

Detailed Description

The invention will be further described with reference to the accompanying drawings.

The pretensioning prestressed reinforcement slow-tension member (see fig. 6) comprises a large bearing plate 1 (see fig. 1), a middle bearing plate 2 (see fig. 3), a small bearing plate 3 (see fig. 2), a middle sliding block 4 (see fig. 4), a small sliding block 5 (see fig. 5) and a limit bolt rod 6 (see fig. 6); the cross section of the large bearing plate 1 consists of an isosceles trapezoid and a rectangle; the cross sections of the middle bearing plate and the small bearing plate are the same as the cross section of the large bearing plate; the height of the large bearing plate is sequentially greater than that of the middle bearing plate and that of the small bearing plate, and the sum of the height of the middle bearing plate and that of the small bearing plate is equal to that of the large bearing plate; the large bearing plate 1, the middle bearing plate 2 and the small bearing plate 3 are provided with first round holes 7; the middle slide block 4 is a cylinder with an isosceles trapezoid cross section; the cross section of the small sliding block 5 is the same as that of the middle sliding block; the height of the middle sliding block is greater than that of the small sliding block, and the height of the middle sliding block and that of the small sliding block are greater than that of the large bearing plate; second round holes 8 are formed in the middle sliding block and the small sliding block; the limiting bolt rod 6 penetrates through the second round hole; the isosceles trapezoid base angle beta of the cross section of the middle slide block 4 and the isosceles trapezoid base angle alpha of the cross section of the large bearing plate 1 form a complementary angle.

The following specific examples are not intended to limit the invention.

The cross sections of the large bearing plate, the middle bearing plate and the small bearing plate are the same, the width of the cross section rectangle is 10mm, the sum of the width of the cross section rectangle and the height of the cross section isosceles trapezoid is 40mm, and the large bearing plate is made of steel plates.

The isosceles trapezoid of the cross section of each bearing plate preferably has a base angle alpha of 20 degrees and is arranged on the large bearing plate, and the holes on the middle bearing plate and the small bearing plate correspond to the positions of the prestressed reinforcements and are used for penetrating the prestressed reinforcements. The bearing plate is mainly used for bearing pressure generated by tensioning. During assembly, the height of the bearing plate close to the pedestal steel plate is 260mm, the height of the bearing plate far away from the pedestal steel plate is 160mm, the middle bearing plate is arranged below the pedestal steel plate, and the height of the bearing plate is 100mm, the middle bearing plate is arranged above the small bearing plate. Two rows of first round holes 7 are distributed on the large bearing plate, and each row is provided with 5 first round holes (the number of the first round holes is the same as that of the prestressed reinforcement). Two rows of first round holes 7 are distributed on the middle bearing plate, and each row is provided with 3. Two rows of first round holes 7 are distributed on the small bearing plate, 2 are distributed on each row, and the sum of the number of the first round holes on the middle bearing plate and the small bearing plate is the same as the number of the first round holes on the large bearing plate.

The cross sections of the small sliding block and the middle sliding block are both 30mm high and are made of steel plates; the small slide block is 100mm high, and the middle slide block is 160mm high;

and 2 second round holes are formed in the small sliding block and the middle sliding block, and a row of second round holes is distributed in the middle sliding block. The small slide block is provided with 1 row of second round holes.

The slide block mainly functions in supporting the bearing plate and transferring stress to the limit bolt rod.

The limit bolt rod adopts a 10.8-grade M18 screw rod and matched nuts and gaskets and is mainly used for bearing the pressure transmitted by the sliding blocks and adjusting the distance between the sliding blocks, so that the distance between the pressure bearing plates is controlled, and the expansion is realized.

The invention is suitable for all pretensioning method prestressed member construction, and the sizes and hole arrangement of the bearing plate and the sliding block need to be adjusted according to the sizes and the steel bar arrangement of different prestressed members.

Instructions for use (see FIG. 7)

(1) All prestressed reinforcements 10 penetrate through holes of a pedestal steel plate 11 and first round holes of a bearing plate, a limiting bolt rod 6 penetrates through second round holes of a sliding block, the positions of the bearing plate and the sliding block are adjusted, a clamping device 9 is installed, and the bearing plate and the sliding block are fastened.

(2) Tensioning the prestressed reinforcement;

(3) loosening the nut on the limit bolt rod on the small sliding block after the concrete pouring of the component is finished and the design strength is reached; the small bearing plate is moved to one side of the large bearing plate, so that the prestress tension releasing is performed. In the same way, the nut on the limit bolt rod on the middle sliding block is loosened; the middle bearing plate is moved to one side of the large bearing plate, so that prestress tension releasing is carried out.

(4) After the prestress tension releasing is finished, the middle sliding block and the middle bearing plate are sequentially installed, a bolt is inserted, the distance between the sliding blocks is reasonably adjusted according to the tension force of the prestressed tendon, and the enough tension releasing distance is ensured to be reserved. And cutting the exposed prestressed reinforcement.

Claims

1. The pretensioning prestressed reinforcement slow-tension member is characterized by comprising a large bearing plate (1), a middle bearing plate (2), a small bearing plate (3), a middle sliding block (4), a small sliding block (5) and a limiting bolt rod (6); the cross section of the large bearing plate (1) consists of an isosceles trapezoid and a rectangle; the cross sections of the middle bearing plate and the small bearing plate are the same as the cross section of the large bearing plate; the height of the large bearing plate is sequentially greater than that of the middle bearing plate and that of the small bearing plate, and the sum of the height of the middle bearing plate and that of the small bearing plate is equal to that of the large bearing plate; the large bearing plate (1), the middle bearing plate (2) and the small bearing plate (3) are provided with first round holes (7); the middle sliding block (4) is a cylinder with an isosceles trapezoid cross section; the cross section of the small sliding block is the same as that of the middle sliding block; the height of the middle sliding block is greater than that of the small sliding block, and the height of the middle sliding block and that of the small sliding block are greater than that of the large bearing plate; second round holes (8) are formed in the middle sliding block and the small sliding block; the limiting bolt rod (6) penetrates through the second round hole; the base angle beta of the isosceles trapezoid of the cross section of the middle sliding block (4) and the base angle alpha of the isosceles trapezoid of the cross section of the large bearing plate (1) are complementary angles.