Connecting sleeve for bonding fatigue test

Abstract

The utility model discloses a connecting sleeve for a bonding fatigue test, the connecting sleeve is connected with a reinforced concrete drawing test piece and a bottom joint of a fatigue testing machine, the connecting sleeve comprises a sleeve pressurizing section and a threaded connecting section which are integrally formed, and a positioning screw piece and a pressurizing screw piece are arranged on the sleeve pressurizing section; the interior of the threaded connection section is hollow, an external thread part is arranged on the outer side wall of the threaded connection section, and an internal thread part is arranged on the inner side wall of the threaded connection section; the positioning screw piece comprises a plurality of positioning screws which are close to the end part of the sleeve pressurizing section and are uniformly distributed along the circumferential direction of the sleeve pressurizing section; the forcing screw pieces are arranged in multiple rows, and the multiple rows of forcing screw pieces are arranged in the height direction of the sleeve forcing section. The device is reasonable in design, the connecting sleeve is used for connection, the fatigue strength of the connecting position is improved, the loading end of the reinforcing steel bar cannot be broken in advance, and therefore the device adapts to the bonding fatigue test, the test success rate is improved, cost is low, and adaptability is good.

Description

Technical Field

[0001] The utility model belongs to the technical field of reinforced concrete bond performance test devices, and particularly relates to a connecting sleeve for bond fatigue tests. Background Technique

[0002] With the development of China's social economy, transportation infrastructure across the country has been gradually improved. Reinforced concrete bridges, as important building structures spanning rivers, cliffs and other terrains, have been widely used. During the service life of such bridges, they are damaged by vehicle loads, freeze-thaw cycles, chloride salt erosion, etc., resulting in the degradation of the bond performance at the reinforced concrete interface, which in turn leads to bridge cracking and increased beam deformation, reducing the durability of the bridge. Therefore, the research on the bond performance of reinforced concrete is very important for the durability design of bridges, which is related to the safety, reliability and durability of concrete structures. Therefore, it is very necessary to test the bond performance of reinforced concrete.

[0003] Currently, during the detection of bond performance, when fatigue loading tests are used, due to the fast loading frequency and long loading time, clamps are required at the joints of reinforced concrete pull-out specimens, and the requirements for the clamps are relatively high. Therefore, the clamps for realizing fatigue loading are expensive, which will increase the test cost. If some do not have the corresponding clamps, the steel bars are threaded and then connected to the testing machine, and fatigue fracture often occurs prematurely at the threaded part of the steel bars, resulting in test failure. Therefore, when implementing bond fatigue tests, there are currently problems such as being greatly restricted by clamps, high test costs, and high test failure rates.

[0004] Therefore, there is an urgent need for a connecting sleeve for bond fatigue tests with a simple structure and reasonable design. The steel bars in the reinforced concrete pull-out specimens are connected to the bottom joints of the testing machine through the connecting sleeve, which improves the fatigue strength of the joints, so that the loading ends of the steel bars will not break prematurely, thus adapting to bond fatigue tests, improving the test success rate, having low cost, and good adaptability. Content of the Utility Model

[0005] The technical problem to be solved by the utility model is to provide a connecting sleeve for bond fatigue tests aiming at the deficiencies in the above-mentioned prior art. It has a simple structure and reasonable design. The steel bars in the reinforced concrete pull-out specimens are connected to the bottom joints of the testing machine through the connecting sleeve, which improves the fatigue strength of the joints, so that the loading ends of the steel bars will not break prematurely, thus adapting to bond fatigue tests, improving the test success rate, having low cost, and good adaptability.

[0006] To solve the above technical problems, the technical solution adopted by the present utility model is as follows: A connecting sleeve for bond fatigue test, the connecting sleeve connects a reinforced concrete pull-out specimen and the bottom joint of a fatigue testing machine, and is characterized in that: the connecting sleeve includes an integrally formed sleeve pressurizing section and a threaded connection section, and a positioning screw member and a pressurizing screw member are arranged on the sleeve pressurizing section;

[0007] The threaded connection section is internally hollow, an external thread portion is arranged on the outer side wall of the threaded connection section, and an internal thread portion is arranged on the inner side wall of the threaded connection section;

[0008] The positioning screw member includes a plurality of positioning screws that are close to the end of the sleeve pressurizing section and are evenly distributed along the circumferential direction of the sleeve pressurizing section;

[0009] The pressurizing screw member is arranged in multiple rows, and the multiple rows of pressurizing screw members are arranged along the height direction of the sleeve pressurizing section.

[0010] For the above-mentioned connecting sleeve for bond fatigue test, it is characterized in that: the multiple rows of pressurizing screw members are respectively the first row of pressurizing screw members, the second row of pressurizing screw members and the third row of pressurizing screw members from the positioning screw to the threaded connection section. The first row of pressurizing screw members includes a plurality of first pressurizing screws that are evenly distributed along the circumferential direction of the sleeve pressurizing section. The second row of pressurizing screw members includes a plurality of second pressurizing screws that are evenly distributed along the circumferential direction of the sleeve pressurizing section. The third row of pressurizing screw members includes a plurality of third pressurizing screws that are evenly distributed along the circumferential direction of the sleeve pressurizing section.

[0011] For the above-mentioned connecting sleeve for bond fatigue test, it is characterized in that: each of the single positioning screw, the first pressurizing screw, the second pressurizing screw and the third pressurizing screw is arranged radially along the sleeve pressurizing section.

[0012] For the above-mentioned connecting sleeve for bond fatigue test, it is characterized in that: the number of the positioning screw, the first pressurizing screw, the second pressurizing screw and the third pressurizing screw is three each.

[0013] For the above-mentioned connecting sleeve for bond fatigue test, it is characterized in that: multiple rows and multiple columns of screw holes for the positioning screw, the first pressurizing screw, the second pressurizing screw and the third pressurizing screw to pass through are arranged on the sleeve pressurizing section.

[0014] For the above-mentioned connecting sleeve for bond fatigue test, it is characterized in that: the reinforced concrete pull-out specimen includes a cast concrete block and a steel bar passing through the concrete block. Both ends of the steel bar extend out of the concrete block, and a connecting thread is arranged at the lower end of the steel bar extending out of the concrete block;

[0015] The lower end of the steel bar passes through the sleeve pressing section and is connected in cooperation with the internal thread part of the threaded connection section, and the external thread part of the threaded connection section extends into the internal thread of the bottom joint for connection.

[0016] The utility model has the following advantages compared with the prior art:

[0017] 1. The structure of the utility model is simple, the disassembly and assembly are convenient, it meets the requirements of the bonding fatigue test, the cost is low, and it solves the problems that the current test cost is high due to the large limitation of the fixture or the high failure rate of the test without using the fixture at present.

[0018] 2. The threaded connection section is provided in the utility model so that the external thread part of the threaded connection section is connected to the bottom joint of the fatigue testing machine, and the internal thread part of the threaded connection section is connected to the steel bar of the reinforced concrete pull-out specimen, thereby realizing the connection between the steel bar in the reinforced concrete pull-out specimen and the bottom joint of the testing machine. The installation is convenient and the fatigue strength of the connection part is improved.

[0019] 3. The positioning screw is provided in the utility model to initially position the steel bar and ensure that the steel bar and the sleeve pressing section are coaxially arranged; the pressing screw member is provided to tighten the outer side wall of the steel bar of the reinforced concrete pull-out specimen, so that the pressing screw provides a lateral extrusion force for the test, further preventing the fracture of the bonded steel bar thread section during the test to avoid the test failure.

[0020] In summary, the utility model has a simple structure and reasonable design. The steel bar in the reinforced concrete pull-out specimen is connected to the bottom joint of the testing machine through a connecting sleeve, which improves the fatigue strength of the connection part, so that the steel bar loading end will not break in advance, thus meeting the bonding fatigue test, improving the test success rate, having a low cost and good adaptability.

[0021] The technical solution of the utility model will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0022] Figure 1 It is a structural schematic diagram of the utility model.

[0023] Figure 2 It is a structural schematic diagram of the installation of the steel bar in the reinforced concrete pull-out specimen of the utility model.

[0024] Figure 3 It is a use state diagram of the utility model.

[0025] Description of the Reference Numerals:

[0026] 1 - Sleeve pressing section; 2 - Threaded connection section; 3 - Positioning screw;

[0027] 4 - Pressing screw member; 4-1 - First pressing screw; 4-2 - Second pressing screw;

[0028] 4 - 3—the third pressure screw; 5—external thread part; 6—internal thread part;

[0029] 8—reinforced concrete pull - out test piece; 8 - 1—steel bar;

[0030] 8 - 1 - 1—connecting thread; 8 - 2—concrete block;

[0031] 10—connecting sleeve; 11—fatigue testing machine; 11 - 1—bottom joint;

[0032] 12—reaction frame; 13—hydraulic loading head. Specific embodiments

[0033] As Figures 1 to 3 shown, the connecting sleeve 10 of the present utility model connects the reinforced concrete pull - out test piece 8 and the bottom joint 11 - 1 of the fatigue testing machine 11, and is characterized in that: the connecting sleeve 10 includes an integrally formed sleeve pressurizing section 1 and a threaded connection section 2, and a positioning screw member and a pressure screw member 4 are arranged on the sleeve pressurizing section 1;

[0034] The threaded connection section 2 is hollow inside, an external thread part 5 is arranged on the outer side wall of the threaded connection section 2, and an internal thread part 6 is arranged on the inner side wall of the threaded connection section 2;

[0035] The positioning screw member includes a plurality of positioning screws 3 that are close to the end of the sleeve pressurizing section 1 and are evenly distributed along the circumferential direction of the sleeve pressurizing section 1;

[0036] The pressure screw member 4 is arranged in multiple rows, and the multiple rows of the pressure screw member 4 are arranged along the height direction of the sleeve pressurizing section 1.

[0037] In this embodiment, the multiple rows of the pressure screw member 4 are respectively the first - row pressure screw member, the second - row pressure screw member and the third - row pressure screw member from the positioning screw 3 to the threaded connection section 2. The first - row pressure screw member includes a plurality of first pressure screws 4 - 1 that are evenly distributed along the circumferential direction of the sleeve pressurizing section 1. The second - row pressure screw member includes a plurality of second pressure screws 4 - 2 that are evenly distributed along the circumferential direction of the sleeve pressurizing section 1. The third - row pressure screw member includes a plurality of third pressure screws 4 - 3 that are evenly distributed along the circumferential direction of the sleeve pressurizing section 1.

[0038] In this embodiment, each of the single positioning screw 3, the first pressure screw 4 - 1, the second pressure screw 4 - 2 and the third pressure screw 4 - 3 is arranged along the radial direction of the sleeve pressurizing section 1.

[0039] In this embodiment, the number of the positioning screw 3, the first pressure screw 4 - 1, the second pressure screw 4 - 2 and the third pressure screw 4 - 3 is three each.

[0040] In this embodiment, multiple rows and columns of screw holes for the positioning screw 3, the first pressing screw 4-1, the second pressing screw 4-2 and the third pressing screw 4-3 to pass through are provided on the sleeve pressing section 1.

[0041] In this embodiment, the reinforced concrete pull-out specimen 8 includes a cast concrete block 8-2 and a reinforcing bar 8-1 passing through the concrete block 8-2. Both ends of the reinforcing bar 8-1 extend out of the concrete block 8-2, and a connecting thread 8-1-1 is provided at the lower end of the reinforcing bar 8-1 extending out of the concrete block 8-2.

[0042] The lower end of the reinforcing bar 8-1 passes through the sleeve pressing section 1 and is in threaded connection with the internal threaded portion 6 of the threaded connection section 2, and the external threaded portion 5 of the threaded connection section 2 extends into the internal thread of the bottom joint 11-1 for threaded connection.

[0043] In this embodiment, the length of the sleeve pressing section 1 is 90 mm, and the length of the threaded connection section 2 is 60 mm. It should be noted that the threaded connection section 2 is formed by threading on the same structure as the sleeve pressing section 1. Therefore, the threaded part is the threaded connection section 2, the sleeve pressing section 1 is a cylindrical barrel, the outer diameter of the sleeve pressing section 1 is 27 mm, and the inner diameter is 16 mm.

[0044] In this embodiment, the numbers of the positioning screw 3, the first pressing screw 4-1, the second pressing screw 4-2 and the third pressing screw 4-3 can be adjusted as needed.

[0045] In this embodiment, multiple rows and columns of screw holes are provided on the sleeve pressing section 1, and the sizes of the screw holes are all M8. There are 4 rows and 3 columns of screw holes, and the included angles between the connecting lines of the centers of the circular cross-sections of the adjacent two columns of screw holes and the sleeve are both 120°, and the interval between two adjacent screw holes in two adjacent rows is 15 mm.

[0046] When the utility model is specifically used, a reinforced concrete pull-out specimen 8 is pre-cast, and both ends of the reinforced concrete pull-out specimen 8 extend out of the concrete block 8-2. A connecting thread 8-1-1 is provided at the lower end of the reinforcing bar 8-1 extending out of the concrete block 8-2. The reinforced concrete pull-out specimen 8 is installed on the bottom of the reaction frame 12, and the lower end of the reinforcing bar 8-1 extending out of the concrete block 8-2 passes through the bottom of the reaction frame 12.

[0047] Then, pass the steel bar 8-1 through the lower end of the reaction frame 12 and insert it into the sleeve pressurizing section 1. After the lower end of the steel bar 8-1 passes through the sleeve pressurizing section 1 and is connected to the internal thread part 6 of the threaded connection section 2 in a threaded manner, first screw three positioning screws 3 to contact the steel bar 8-1 for initial positioning to ensure that the steel bar 8-1 and the sleeve pressurizing section 1 are coaxially arranged. Then, screw the first pressurizing screw 4-1, the second pressurizing screw 4-2, and the third pressurizing screw 4-3 until they are tightened against the outer wall of the steel bar 8-1. In this way, the pressurizing screws provide lateral extrusion force for the test to assist in preventing the bonded steel bar thread section from breaking during the test and avoiding test failure.

[0048] Next, extend the external thread part 5 of the threaded connection section 2 into the bottom joint 11-1 of the fatigue testing machine 11 and connect them in a threaded manner to ensure that the connecting sleeve 10 and the fatigue testing machine 11 are connected as a whole, so that the subsequent test can proceed smoothly. Among them, the hydraulic loading head 13 of the fatigue testing machine 11 acts on the concrete block 8-2 through the reaction frame 12 for fatigue testing.

[0049] To sum up, the structure of the utility model is simple and reasonably designed. The steel bar in the reinforced concrete pull-out specimen is connected to the bottom joint of the testing machine through a connecting sleeve, which improves the fatigue strength of the connection part, so that the steel bar loading end will not break prematurely, thus adapting to the bonded fatigue test, improving the test success rate, having a low cost, and good adaptability.

[0050] The above is only a preferred embodiment of the utility model, and does not impose any limitation on the utility model. Any simple modification, change, and equivalent structural change made to the above embodiment according to the technical essence of the utility model still fall within the protection scope of the technical solution of the utility model.

Claims

1. A connecting sleeve for bond fatigue test, wherein the connecting sleeve (10) connects a reinforced concrete pull-out specimen (8) with a bottom joint (11-1) of a fatigue testing machine (11), and is characterized in that: The connecting sleeve (10) includes an integrally formed sleeve pressing section (1) and a threaded connection section (2), and a positioning screw member and a pressing screw member (4) are arranged on the sleeve pressing section (1); The threaded connection section (2) is hollow inside, an external thread portion (5) is arranged on the outer side wall of the threaded connection section (2), and an internal thread portion (6) is arranged on the inner side wall of the threaded connection section (2); The positioning screw member includes a plurality of positioning screws (3) that are close to the end of the sleeve pressing section (1) and are evenly distributed along the circumferential direction of the sleeve pressing section (1); The pressing screw member (4) has multiple rows, and the multiple rows of the pressing screw member (4) are arranged along the height direction of the sleeve pressing section (1).

2. The connecting sleeve for the bonding fatigue test according to claim 1, wherein: The multiple rows of the pressing screw member (4) are respectively a first row of pressing screw members, a second row of pressing screw members, and a third row of pressing screw members from the positioning screw (3) to the threaded connection section (2). The first row of pressing screw members includes a plurality of first pressing screws (4-1) that are evenly distributed along the circumferential direction of the sleeve pressing section (1). The second row of pressing screw members includes a plurality of second pressing screws (4-2) that are evenly distributed along the circumferential direction of the sleeve pressing section (1). The third row of pressing screw members includes a plurality of third pressing screws (4-3) that are evenly distributed along the circumferential direction of the sleeve pressing section (1).

3. The connecting sleeve for bonding fatigue test according to claim 2, characterized in that: Each of the single positioning screw (3), the first pressing screw (4-1), the second pressing screw (4-2), and the third pressing screw (4-3) is arranged along the radial direction of the sleeve pressing section (1).

4. A connecting sleeve for a bonding fatigue test according to claim 2, characterized in that: The number of the positioning screw (3), the first pressing screw (4-1), the second pressing screw (4-2), and the third pressing screw (4-3) is three each.

5. A connecting sleeve for a bonding fatigue test according to claim 2, characterized in that: Multiple rows and multiple columns of screw holes for the positioning screw (3), the first pressing screw (4-1), the second pressing screw (4-2), and the third pressing screw (4-3) to penetrate are arranged on the sleeve pressing section (1).

6. The connecting sleeve for the bonding fatigue test according to claim 1, characterized in that: The reinforced concrete pull-out test piece (8) includes a cast concrete block (8-2) and a steel bar (8-1) inserted into the concrete block (8-2). Both ends of the steel bar (8-1) extend out of the concrete block (8-2), and a connecting thread (8-1-1) is arranged at the lower end of the steel bar (8-1) extending out of the concrete block (8-2); The lower end of the steel bar (8-1) passes through the sleeve pressing section (1) and is in fit connection with the internal thread portion (6) of the threaded connection section (2), and the external thread portion (5) of the threaded connection section (2) extends into the internal thread connection of the bottom joint (11-1).

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