Device for studying durability of rib material under continuous tension load and environment coupling effect

Abstract

The utility model discloses a device for studying the durability of a rib material under the coupling action of a continuous tension load and an environment. The device comprises a threaded steel pipe, the rib material, a screw rod, a first stress disc, a second stress disc, a third stress disc, a concrete pouring mold, a jack and a detection device, the threaded steel pipes are fixed to the two ends of the rib material, the rib material is arranged in the concrete pouring mold, the threaded steel pipes at the two ends of the rib material and the two ends of the threaded rod are fixed to the first stress disc and the second stress disc respectively through nuts, a jack is arranged on the stress disc at one end, and a third stress disc is arranged at the other end of the jack. The detection device is arranged between the second stress disc and the third stress disc; the device is simple in structure, multiple groups of rib materials can be tested at the same time, meanwhile, the screw is arranged between every two adjacent rib materials, the applied drawing force level is guaranteed, the test precision is improved, errors are reduced, and the stability and reliability of the test device are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to concrete material test technical field especially relates to a device for researching the durability of the reinforcement under the coupling action of the sustained tension load and the environment. BACKGROUND

[0002] In recent years, the marine economy develops rapidly, with the development of marine economy, the construction of wharf and other offshore platforms is particularly important. The development of marine economy cannot be separated from the construction of structures such as port wharf, offshore platform and the like. However, the marine service environment is hot and humid, there are many corrosive ions, and the wave erosion effect is obvious. The conventional reinforced concrete structure faces severe durability problems, which is not conducive to the safety of people's life and property. The core of the durability problem of reinforced concrete is the corrosion of steel bars. Fiber reinforced polymer (Fibre reinforced polymer, FRP) has the advantages of high corrosion resistance, light weight, high strength and high cost performance. It is expected to improve the durability of concrete structure by replacing steel bars with reinforcement in concrete structure.

[0003] Before widely using FRP bars to replace steel bars in concrete, it is necessary to conduct a large number of experimental researches to explore the durability of FRP bars under different environmental actions and provide theoretical basis for the corresponding structure design method. At the same time, due to the influence of factors such as self weight of component, equipment operation, personnel flow and the like, the structure is subjected to the coupling action of load and environment in the service process. The existing research shows that compared with the simple durability of the environment, the durability of FRP bars under the coupling action of load and environment is significantly reduced. Therefore, it is necessary to further study the durability of FRP bars under the coupling action of load and environment. The longitudinal reinforcement of FRP bars mainly bears the tension load in the concrete flexural member, and the research on the durability of FRP bars under the coupling action of sustained tension load and environment is the key to the promotion and application of FRP bars in concrete structure.

[0004] In the existing research, the lever method and the tension method are usually used to apply a sustained tensile load to the FRP bar. The lever method mainly adjusts the force arm through the lever principle, cooperates with the movable pulley and the weight to make the bar bear the corresponding tensile load. However, the construction cost of the lever method device is high, the space occupied is large, the moving difficulty is large, and it is not easy to investigate the coupling effect of load and environment in the field and laboratory environment. The tension method mainly cooperates with the jack and the force sensor to tension the FRP bar to a certain deformation, releases the jack, and uses the screw and the nut to limit the retraction of the FRP bar to make the bar bear the sustained tensile load. The published patent CN111665133A uses the tension method to apply a sustained tensile load to the FRP bar. However, whether it is the national standard or the international standard, it is required to prepare more than three repeated test pieces. The load application method of the published patent CN111665133A is only suitable for one test sample. If the standard requirements are to be met, not only a large economic cost is needed to customize multiple sets of devices, but also a large amount of manpower and time cost is consumed. In addition, in order to reflect the real situation of the FRP bar serving in the concrete structure, it is necessary to pour a dense concrete protective layer around the FRP bar, and the existing devices and methods are relatively difficult to realize this operation.

[0005] The Chinese patent No. CN111579481A discloses a kind of sustained load and corrosion environment coupling under FRP bar and concrete bonding performance test device, the device includes FRP bar, first PVC sleeve, second PVC sleeve, first PVC sleeve, second PVC sleeve is movably sleeved on the outer surface of FRP bar, FRP bar and concrete bonding structure form FRP bar concrete pull-out test piece, also includes corrosion solution tank, corrosion solution tank is equipped with corrosion solution, first cement mortar pad and second cement mortar pad are placed in parallel at the bottom of corrosion solution tank, FRP bar concrete pull-out test piece is placed on first cement mortar pad and second cement mortar pad, and the concrete of FRP bar concrete pull-out test piece is in contact with the upper plane of first cement mortar pad and second cement mortar pad, first steel backing plate, load sensor, second steel backing plate and pressure screw nut are sequentially arranged on the concrete of FRP bar concrete pull-out test piece, the upper part of FRP bar sequentially passes through first steel backing plate, load sensor and second steel backing plate, and the pipe thread fixed on the upper part of FRP bar is threadedly connected with pressure screw nut;The device applies pulling force through nut, threaded steel sleeve and steel backing plate to carry out test.

[0006] However, the above-mentioned patent only uses one group of bars for testing when conducting tests, and there is a large error in the durability test of a single group of bars, and the applied pulling force may be inclined, resulting in increased error.

[0007] In order to overcome the above-mentioned shortcomings of the device and method for applying continuous tension load to the reinforcing bar, the utility model provides a device for researching the durability of reinforcing bar under the coupling action of continuous tension load and environment, which can simultaneously conduct continuous tension load test on multiple groups of reinforcing bars, improve test accuracy and reduce errors. Utility model content

[0008] In order to solve the above-mentioned problems, the utility model discloses a device for researching the durability of reinforcing bar under the coupling action of continuous tension load and environment, which has simple structure, can simultaneously conduct experiments on multiple groups of reinforcing bars, reduces errors, uses conventional parts, has low economic cost and is more suitable for laboratory environment.

[0009] In order to solve the above-mentioned problems, the utility model discloses a device for researching the durability of reinforcing bar under the coupling action of continuous tension load and environment, which has simple structure, can simultaneously conduct experiments on multiple groups of reinforcing bars, reduces errors, uses conventional parts, has low economic cost and is more suitable for laboratory environment.

[0010] The utility model discloses a device for researching the durability of reinforcing bar under the coupling action of continuous tension load and environment, including screw steel pipe, reinforcing bar, screw rod, first force disc, second force disc, third force disc, concrete pouring mold, jack, detection device, the both ends of reinforcing bar are fixed with screw steel pipe, and the reinforcing bar is arranged in concrete pouring mold, and the both ends of reinforcing bar screw steel pipe with screw rod both ends are fixed on first force disc, second force disc through nut respectively, one end of force disc is equipped with jack, and the other end of jack is equipped with third force disc, and detection device sets up between second force disc and third force disc.

[0011] Further, the concrete pouring mold includes a large PVC pipe, a small PVC pipe and a pipe cap. The large PVC pipe has pipe caps at both ends, and the pipe caps have through holes. The small PVC pipe is bonded to the pipe cap at one end of the large PVC pipe.

[0012] Further, the detection device includes a tension sensor and a tension display. The tension sensor has threaded interfaces at both ends. One end is connected to the screw rod, and the other end is fixed with the screw steel pipe. The tension display is electrically connected to the tension sensor.

[0013] Further, the screw steel pipe fixed to one end of the tension sensor is fixed to the third force disc at the other end.

[0014] Further, the detection device includes a pressure sensor and a pressure display. The pressure sensor is arranged between the third force disc and the jack. The pressure display is electrically connected to the pressure sensor.

[0015] Further, the screw steel pipe at one end of the reinforcing bar is fixedly installed on the first force disc by a bolt. The bolt is installed below the first force disc. The screw steel pipe at the other end is fixedly installed on the second force disc by a bolt. The bolt is installed above the second force disc.

[0016] Further, the screw rod is installed with the first force disc through bolts, the bolts are installed on the first force disc, the screw rod is installed with the second force disc through bolts, and the bolts are arranged below the second force disc.

[0017] Further, the screw rod is installed with the first force disc through bolts, the bolts are installed on the first force disc, the screw rod is installed with the second force disc through bolts, and the bolts are arranged below the second force disc.

[0018] Further, the screw rod is installed with the first force disc through bolts, the bolts are installed on the first force disc, the screw rod is installed with the second force disc through bolts, and the bolts are arranged below the second force disc.

[0019] Compared with the prior art, the device has the advantages and positive effects that:

[0020] 1. The device has simple structure, and can perform multiple group of reinforcement tests at the same time, and the screw rod is arranged between two adjacent reinforcement bars to ensure the horizontal pulling force, improve the test accuracy, reduce the error, and improve the stability and reliability of the test device.

[0021] 2. The device adopts conventional parts, which greatly reduces the test cost and test requirements under the condition of ensuring the accuracy of test data, and easily forms a load and durability coupling environment with the existing laboratory durability equipment and on-site test conditions. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A device structure schematic diagram for researching the durability performance of reinforcement under the coupling action of continuous tension load and environment;

[0023] Figure 2 A force disc schematic diagram of the device for researching the durability performance of reinforcement under the coupling action of continuous tension load and environment;

[0024] Figure 3 A reinforcement and threaded steel pipe structure schematic diagram of the device for researching the durability performance of reinforcement under the coupling action of continuous tension load and environment;

[0025] Figure 4 A pressure sensor installation schematic diagram of the device for researching the durability performance of reinforcement under the coupling action of continuous tension load and environment;

[0026] Figure 5 A tension sensor installation schematic diagram of the device for researching the durability performance of reinforcement under the coupling action of continuous tension load and environment;

[0027] Figure 6 A force disc installation schematic diagram of the device for researching the durability performance of reinforcement under the coupling action of continuous tension load and environment;

[0028] Figure 7 A multiple group of environment coupling schematic diagram of the device and the water tank.

[0029] Legend:

[0030] 1. Threaded steel pipe; 2. Reinforcing steel; 3. Screw; 4. Hex nut; 5. Washer; 6. Force-bearing disc; 6-1. First force-bearing disc; 6-2. Second force-bearing disc; 6-3. Third force-bearing disc; 7. Plastic pipe cap; 8. Large PVC pipe; 9. Small PVC pipe; 10. Tension sensor; 11. Tension display; 12. Jack; 13. Pressure sensor; 14. Pressure display. Detailed Implementation

[0031] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0032] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed in the following specification.

[0033] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings:

[0034] like Figures 1-7 As shown: A device for studying the durability of reinforcing bars under the coupled action of sustained tensile load and environment includes threaded steel pipes 1, reinforcing bars 2, screws 3, hexagonal nuts 4, washers 5, and a load-bearing disc. The threaded steel pipes 1 are infused with epoxy resin. The two ends of the reinforcing bars 2 are respectively inserted into one of the threaded steel pipes 1. After curing at room temperature for seven days, the reinforcing bars 2 and threaded steel pipes 1 are completely fixed, preparing four integral samples of the reinforcing bars 2 and threaded steel pipes 1. The screws 3 have external threads at both ends, and four screws 3 of the same specification are provided. The first load-bearing disc 6-1 has eight through holes. The lower ends of the threaded steel pipes 1 of the four reinforcing bars 2 and the lower ends of the four screws 3 are fixed to the first load-bearing disc 6-1 by hexagonal nuts 4. A washer 5 is provided between the hexagonal nut 4 and the first force-bearing disc 6-1. At the same time, the hexagonal nut 4 is screwed into the lower end of the screw rod 3 to a greater depth than the screwing depth of the threaded steel pipe 1. The screw rod 3 and the threaded steel pipe 1 are distributed circumferentially on the first force-bearing disc 6-1. The hexagonal nut 4 and the washer 5 are fitted onto the upper end of the screw rod 3. Then, the screw rod 3 and the threaded steel pipe 1 are sequentially fitted into the second force-bearing disc 6-2 at intervals. The hexagonal nut 4 is fitted onto the screw rod 3, so that the second force-bearing disc 6-2 is fixed at the upper end of the screw rod 3, and the weight of the second force-bearing disc 6-2 is completely borne by the screw rod 3. At the same time, the screwing depth of the hexagonal nut 4 at the lower end of the screw rod 3 is adjusted so that the first force-bearing disc 6-1 and the second force-bearing disc 6-2 are kept in a horizontal state.

[0035] The hexagonal nut 4 at the upper end of the screw rod 3 is located below the second force disk 6-2, and the hexagonal nut 4 on the threaded steel pipe 1 above the rib material 2 is located above the second force disk 6-2.

[0036] In the embodiment, a concrete pouring mold, a detection device and a jack 12 are further included. The concrete pouring mold includes a plastic pipe cap 7, a large PVC pipe 8 and a small PVC pipe 9. The plastic pipe cap 7 is clamped at both ends of the large PVC pipe 8. The small PVC pipe 9 is adhered to the plastic pipe cap 7 at the lower end of the large PVC pipe 8 by hot melt glue. The length of the small PVC pipe 9 is equal to the length of the threaded steel pipe 1 protruding above the first force disk 6-1. The length of the large PVC pipe 8 is equal to the length of the rib material 2. The concrete pouring mold is arranged on each rib material 2. The rib material 2 is placed in the large PVC pipe 8. The part of the threaded steel pipe 1 below the rib material 2 protruding above the first force disk 6-1 is placed in the small PVC pipe 9. The lower end of the small PVC pipe 9 is adhered to the first force disk 6-1 by glue.

[0037] The jack 12 is fixed above the second force disk 6-2 at the center of the second force disk 6-2. The screw rod 3 and the threaded steel pipe 1 are arranged around the jack 12.

[0038] The detection device includes a tension sensor 10, a tension display 11, a pressure sensor 13 and a pressure display 14. The tension sensor 10 is provided with threaded interfaces at both upper and lower ends. The lower end is arranged on the threaded steel pipe 1 at the upper end of the rib material 2. The upper end is connected with the screw rod 3. One tension sensor 10 is arranged on each threaded steel pipe 1. The tension sensor 10 is used for monitoring the stress of the four rib materials 2 under the applied tensile load and preventing eccentric tension. The tension sensor 10 is electrically connected with the tension display 11. The tension display 11 is used for displaying the tension value of the tension sensor 10. The pressure sensor 13 is arranged at the position of the center support of the jack 12. The pressure sensor 13 is electrically connected with the pressure display 14. The rib material 2 is subjected to the tensile load by the support force of the jack 12. The load of the support is sensed by the pressure sensor 13. The pressure display 14 is used for displaying the value.

[0039] The upper end of the tension sensor 10 is fixed on the third force disk 6-3 by the hexagonal nut 4. The hexagonal nut 4 is arranged above the third force disk 6-3. The jack 12 is fixed between the second force disk 6-2 and the third force disk 6-3. The pressure sensor 13 is arranged between the jack 12 and the third force disk 6-3.

[0040] Specific working process

[0041] After the installation of the device, the jack 12 is started to pressurize, the jack 12 upwardly supports the pressure sensor 13 and the third force disc 6-3, and the tendon 2 is subjected to a tension load. During the pressurization of the jack 12, the value displayed on the pressure display 14 is observed. When the difference between the maximum value and the minimum value of the values displayed on the four pressure displays 14 is not more than 5% of the maximum load that can be borne by the tendon 2, it is considered that the four tendons 2 obtain the same degree of tension load. When the value displayed by the pressure sensor 13 reaches a preset value, the positions of the four hexagonal nuts 4 and the gaskets 5 on the threaded steel pipes 1 at the upper ends of the tendons 2 are adjusted so that they are in contact with the second force disc 6-2. The jack 12 is closed, and the jack 12 starts to unload. The retraction of the four tendons 2 is limited by the hexagonal nuts 4 and the gaskets 5, and the tension load borne by the tendon 2 is maintained. At this time, the hexagonal nuts 4, the gaskets 5, the third force disc 6-3, the screw rod 3, the tension sensor 10, the tension display 11, the pressure sensor 13, the pressure display 13, the jack 12, and the hexagonal nuts 4 and the gaskets 5 below the screw rod 3 can be removed.

[0042] The opening plastic pipe cap 7 is opened, concrete is poured into the large PVC plastic pipe, and the device is placed on a vibrating table for vibration and compaction. After the large PVC plastic pipe is filled with concrete, the plastic pipe cap 7 is tightened. The device is placed in a standard curing room for curing for 28 days. The plastic pipe cap 7 and the large PVC plastic pipe and the small PVC plastic pipe can be removed, and the tendon 2 sample under the continuous tension load with the concrete wrapping is obtained.

[0043] A tap water environment, a chlorine salt solution, a seawater solution, and an alkaline solution are prepared, respectively, and are filled into different water tanks. The tendon 2 sample wrapped with concrete under the tension load is placed in the water tank filled with different solutions, so that the solution covers the concrete wrapping layer. Different durability time lengths are experienced. During the process, the temperature control switch and the heating rod are combined to heat the solution environment at a fixed temperature, so as to accelerate the degradation of the tendon 2. At the same time, a water pump is installed, and a coupling environment of continuous tension load and dry-wet cycle is formed with another water tank. After the designed durability time length is reached, the hexagonal nut 4 is removed, and the continuous load borne by the tendon 2 is gradually released. After the continuous load in the tendon 2 is completely released, the second force disc 6-2 is removed, and the tendon 2 sample wrapped with concrete is taken out. The tendon 2 sample wrapped with concrete is knocked with a hammer to obtain the tendon 2 subjected to the continuous tension load and the environmental coupling effect.

[0044] The above merely describes preferred embodiments of the present application, and is not intended to limit the present application in other forms, and any skilled person in the art can modify or change the above disclosed technical content to equivalent embodiments applied to other fields with equivalent changes, but any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical scheme of the present application still falls within the protection scope of the present application.

Claims

1. A device for studying the durability performance of a tendon under the coupling of sustained tensile load and environment, characterized in that: The utility model provides a kind of concrete pouring mould and detection device, including threaded steel pipe, bar material, screw rod, first stress disc, second stress disc, third stress disc, concrete pouring mould, jack, detection device;The threaded steel pipe is fixed in the both ends of bar material, and bar material is arranged in concrete pouring mould, and the threaded steel pipe of both ends of bar material is fixed on first stress disc, second stress disc by nut with both ends of screw rod respectively, and one end of stress disc is equipped with jack, and the other end of jack is equipped with third stress disc, and detection device is arranged between second stress disc and third stress disc.

2. The device for studying the durability performance of the tendon under the coupling of the sustained tension load and the environment according to claim 1, characterized in that: The concrete pouring mould includes large PVC pipe, small PVC pipe and pipe cap, both ends of large PVC pipe are equipped with pipe cap, and through hole is opened on pipe cap, and small PVC pipe is bonded on the pipe cap of one end of large PVC pipe.

3. The device for studying the durability performance of the tendon under the coupling of the sustained tension load and the environment according to claim 1, characterized in that: The detection device includes tension sensor and tension display, both ends of tension sensor are equipped with threaded interface, one end is connected with screw rod, and the other end is fixed with threaded steel pipe, and tension display is electrically connected with tension sensor.

4. The device for studying the durability performance of tendon under the coupling action of sustained tension load and environment according to claim 3, characterized in that: It also includes threaded steel pipe fixed with one end of tension sensor, and the other end is fixed on third stress disc.

5. The device for studying the durability performance of tendon under the coupling action of sustained tension load and environment according to claim 1, characterized in that: The detection device includes pressure sensor and pressure display, and pressure sensor is arranged between third stress disc and jack, and pressure display is electrically connected with pressure sensor.

6. The device for studying the durability of the reinforcement under the coupling of the sustained tensile load and the environment according to claim 1, characterized in that: The threaded steel pipe of one end of bar material is fixed and installed on first stress disc by bolt, and bolt is installed below first stress disc, and the threaded steel pipe of the other end is fixed on second stress disc by bolt, and bolt is installed above second stress disc.

7. The device for studying the durability of the reinforcement under the coupling of the sustained tensile load and the environment according to claim 1, characterized in that: The screw rod is installed with first stress disc by bolt, and bolt is installed above and below first stress disc, and screw rod is installed with second stress disc by bolt, and bolt is installed below second stress disc. 8.The device for studying the durability of the tendon under the coupling of the sustained tension load and the environment according to claim 1, characterized in that: Screw rod and bar material are arranged in interval circle.

9. The device for studying the durability of the reinforcement under the coupling of the sustained tensile load and the environment according to claim 1, characterized in that: Both screw rod and bar material are equipped with multiple.

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