Beam type test piece long-term load holding test device

Abstract

The utility model discloses a long-term load holding test device for beam type test pieces. The long-term load holding test device comprises two loading assemblies, two beam type test pieces and a rib material, wherein a single-mode optical fiber is arranged at the position of a bonding section in an attaching and covering manner; the loading assembly comprises a lower side steel plate, a middle steel plate and an upper side steel plate, a vertical screw rod arranged on the lower side steel plate sequentially penetrates through the middle steel plate and the upper side steel plate from bottom to top, and a locking nut is screwed at the upper end part of the vertical screw rod; a jack and a pressure sensor are arranged between the upper side steel plate and the middle steel plate; the middle steel plates are in contact with the upper surfaces of half beams on the corresponding sides of the upper side beam type test pieces through the upper side steel pipes, the lower side steel plates are in abutting contact with the lower surfaces of half beams on the corresponding sides of the lower side beam type test pieces through the lower side steel pipes, and the two middle steel pipes are arranged between the two beam type test pieces. According to the utility model, on one hand, the bond slip test of the rib material and the concrete under the condition of long-term loading under the bending state of the beam can be effectively realized, and on the other hand, the bond slip test of two sets of beam-type test pieces can be efficiently realized at the same time.

Description

Technical Field

[0001] The utility model relates to the technical field of concrete specimen test devices, in particular to a long-term load-bearing test device for beam specimens. Background Art

[0002] The Chinese utility model patent with the patent number ZL202221961087.5 and the patent name "A beam-type reinforced concrete bond-slip test device based on optical fiber measurement" discloses the following technical solutions. Specifically, a beam-type reinforced concrete bond-slip test device based on optical fiber measurement includes two reinforced concrete test pieces, which are connected by a steel hinge. The target test steel bar penetrates through the two reinforced concrete test pieces. A steel sleeve is sleeved on the target test steel bar in the spacer area between the two reinforced concrete test pieces. One end of the target test steel bar is connected to an optical fiber to an optical fiber measuring instrument. By loading the two reinforced concrete test pieces, the bond deformation between the steel bar and the concrete under the applied load is obtained. PVC pipes are respectively sleeved at the end and the middle spacer area of the target test steel bar. The PVC pipe in the middle of the target test steel bar is arranged outside the steel sleeve, forming a non-bonding section between the target test steel bar and the concrete. During operation, the reinforced concrete specimen is loaded to cause it to bend, and the bond-slip deformation condition and performance degradation between the steel bar and the concrete under the applied load are read through the optical fiber connected to the optical fiber measuring instrument.

[0003] It should be noted that for the above-mentioned beam-type reinforced concrete bond-slip test device based on optical fiber measurement, it has the following defects. Specifically, the beam-type reinforced concrete bond-slip test device based on optical fiber measurement essentially discloses a reinforced concrete bond-slip specimen, and this beam-type reinforced concrete bond-slip test device based on optical fiber measurement cannot realize the bond-slip test of the steel bar and the concrete under the long-term load-bearing condition in the beam bending state, let alone realize the bond-slip test of two sets of beam specimens simultaneously. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a long-term load-bearing test device for beam specimens aiming at the deficiencies of the prior art. The structure design of this long-term load-bearing test device for beam specimens is novel. On the one hand, it can effectively realize the bond-slip test of the steel bar and the concrete under the long-term load-bearing condition in the beam bending state. On the other hand, it can efficiently realize the bond-slip test of two sets of beam specimens simultaneously.

[0005] To achieve the above purpose, the utility model is realized through the following technical solutions.

[0006] A long-term load-bearing test device for a beam specimen, comprising a beam specimen. The beam specimen includes embedded steel hinges, reinforcing bars, and two half-beams arranged opposite to each other left and right and having the same dimensions. There is an intermediate gap between the two half-beams, and the two half-beams are connected by the embedded steel hinges; the reinforcing bars and the embedded steel hinges are arranged at intervals up and down. The reinforcing bars horizontally penetrate through the two half-beams in sequence from left to right. The positions where the reinforcing bars are bonded to the half-beams are bonding sections, and single-mode optical fibers are respectively arranged in a covering manner at the bonding sections of the reinforcing bars, and the single-mode optical fibers extend to the outside of the half-beams;

[0007] The long-term load-bearing test device for the beam specimen includes two loading components arranged opposite to each other left and right and at intervals, and two beam specimens arranged at intervals up and down;

[0008] The loading component includes a lower steel plate, an intermediate steel plate, and an upper steel plate arranged at intervals in sequence from bottom to top. The lower steel plate is provided with two vertical screws arranged at intervals front and back and respectively extending vertically. Each vertical screw penetrates through the intermediate steel plate and the upper steel plate in sequence from bottom to top. Locking nuts are respectively screwed on the upper ends of the vertical screws above the upper steel plate; A jack and a pressure sensor are arranged between the upper steel plate and the intermediate steel plate. The upper end of the jack is connected to the upper steel plate, and the lower end of the jack is connected to the intermediate steel plate through the pressure sensor;

[0009] The half-beams on the left side of each beam specimen are respectively located between the intermediate steel plate and the lower steel plate of the left loading component, and the half-beams on the right side of each beam specimen are respectively located between the intermediate steel plate and the lower steel plate of the right loading component; Each intermediate steel plate is in contact with the upper surface of the corresponding half-beam of the upper beam specimen through an upper steel pipe, and each lower steel plate is in pressing contact with the lower surface of the corresponding half-beam of the lower beam specimen through a lower steel pipe. Two intermediate steel pipes are arranged between the upper beam specimen and the lower beam specimen, and the two intermediate steel pipes are located on both sides of the intermediate gap of the beam specimen.

[0010] Among them, the two half-beams of the beam specimen are successively a left half-beam and a right half-beam located at the right end side of the left half-beam. The part of the reinforcing bar extending to the left end side of the left half-beam is the left free end, the part of the reinforcing bar extending to the right end side of the right half-beam is the right free end, and the part of the reinforcing bar located between the left half-beam and the right half-beam is the intermediate loading end;

[0011] A first displacement sensor is fixedly installed at the left free end of the reinforcing bar, a second displacement sensor is fixedly installed at the right free end of the reinforcing bar, an induction part is fixedly installed at the intermediate loading end of the reinforcing bar, a third displacement sensor aligned with the induction part is fixedly installed at the right end of the left half-beam, and a fourth displacement sensor aligned with the induction part is fixedly installed at the left end of the right half-beam.

[0012] Among them, the first displacement sensor is adhesively fixed to the left free end of the tendon by tape, the second displacement sensor is adhesively fixed to the right free end of the tendon by tape, the third displacement sensor is adhesively fixed to the left half beam by tape, and the fourth displacement sensor is adhesively fixed to the right half beam by tape.

[0013] Among them, the bonding section between the tendon and the half beam is located at the middle position of the corresponding half beam, and PVC sleeves are sleeved on both sides of the periphery of the tendon at each bonding section.

[0014] Among them, the tendon is a steel bar or an FRP bar.

[0015] Among them, the width of the intermediate gap is 50 mm.

[0016] Compared with the prior art, the present utility model has the following beneficial effects. Specifically, when the present utility model works, first, each jack is tensioned so that each jack presses downward against the intermediate steel plate on the corresponding side. At this time, the pressure sensor reads the load applied by the jack on the corresponding side. When the pressure value of the pressure sensor reaches the required value, the locking nut is tightened and the position is locked. During this process, the pressure is transmitted to the intermediate steel plate, the upper steel pipe, the upper beam specimen, the intermediate steel pipe, the lower beam specimen, and the lower steel pipe in sequence. At this time, a four-point bending loading force form is formed on both beam specimens. The present utility model can effectively realize the bond-slip test of the tendon and concrete under the bending state of the beam under long-term load holding conditions, and can also efficiently realize the bond-slip test of two sets of beam specimens simultaneously, that is, the beam specimen long-term load holding test device of the first embodiment has the advantages of structural design. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present utility model will be further described below with the aid of the drawings, but the embodiments in the drawings do not constitute any limitation to the present utility model.

[0018] Figure 1 It is a schematic structural diagram of the present utility model.

[0019] Figure 2 It is a schematic structural diagram of another test run of the present utility model.

[0020] Figure 3 It is a schematic cross-sectional view of the beam specimen of the present utility model.

[0021] In Figures 1 to 3 it includes:

[0022] 1 - Beam - type specimen; 11 - Embedded steel hinge; 12 - Reinforcing material; 121 - Left free end; 122 - Right free end; 123 - Intermediate loading end; 13 - Half - beam; 14 - Intermediate gap; 15 - Bonding section; 16 - Sensor; 17 - PVC sleeve; 2 - Loading assembly; 21 - Lower steel plate; 22 - Intermediate steel plate; 23 - Upper steel plate; 24 - Vertical screw; 25 - Locking nut; 26 - Jack; 27 - Pressure sensor; 281 - Upper steel pipe; 282 - Lower steel pipe; 283 - Intermediate steel pipe; 31 - First displacement sensor; 32 - Second displacement sensor; 33 - Third displacement sensor; 34 - Fourth displacement sensor. Detailed implementation mode

[0023] The present utility model will be described below in conjunction with specific implementation modes.

[0024] Example 1, as Figures 1 to 3 shown, a long - term load - holding test device for a beam - type specimen includes a beam - type specimen 1. The beam - type specimen 1 includes an embedded steel hinge 11, a reinforcing material 12, and two half - beams 13 that are arranged opposite to each other left and right and have the same size. There is an intermediate gap 14 between the two half - beams 13, and the two half - beams 13 are connected by the embedded steel hinge 11; the reinforcing material 12 and the embedded steel hinge 11 are arranged at intervals up and down. The reinforcing material 12 horizontally penetrates through the two half - beams 13 from left to right in sequence. The position where the reinforcing material 12 is bonded to the half - beam 13 is the bonding section 15, and single - mode optical fibers (not shown in the figure) are respectively attached to the reinforcing material 12 at the bonding section 15, and the single - mode optical fibers extend to the outside of the half - beam 13.

[0025] Among them, as Figure 1 and Figure 2 shown, the long - term load - holding test device for the beam - type specimen includes two loading assemblies 2 that are arranged opposite to each other left and right and at intervals, and two beam - type specimens 1 that are arranged at intervals up and down.

[0026] Specifically, as Figure 1 and Figure 2 shown, the loading assembly 2 includes a lower steel plate 21, an intermediate steel plate 22, and an upper steel plate 23 that are arranged at intervals from bottom to top. The lower steel plate 21 is provided with two vertical screws 24 that are arranged at intervals front and back and respectively extend vertically. Each vertical screw 24 penetrates through the intermediate steel plate 22 and the upper steel plate 23 from bottom to top in sequence. The upper ends of each vertical screw 24 are respectively screwed with locking nuts 25 above the upper steel plate 23; a jack 26 and a pressure sensor 27 are installed between the upper steel plate 23 and the intermediate steel plate 22. The upper end of the jack 26 is connected to the upper steel plate 23, and the lower end of the jack 26 is connected to the intermediate steel plate 22 through the pressure sensor 27.

[0027] Furthermore, as Figure 1 and Figure 2As shown, the left half-beams 13 of each beam specimen 1 are respectively located between the middle steel plate 22 and the lower steel plate 21 of the left loading assembly 2, and the right half-beams 13 of each beam specimen 1 are respectively located between the middle steel plate 22 and the lower steel plate 21 of the right loading assembly 2; each middle steel plate 22 is respectively in contact with the upper surface of the corresponding-side half-beam 13 of the upper beam specimen 1 through the upper steel pipe 281, and each lower steel plate 21 is respectively in pressing contact with the lower surface of the corresponding-side half-beam 13 of the lower beam specimen 1 through the lower steel pipe 282. Two middle steel pipes 283 are installed between the upper beam specimen 1 and the lower beam specimen 1, and the two middle steel pipes 283 are located on both sides of the middle gap 14 of the beam specimen 1.

[0028] It should be noted that the reinforcing bars 12 in the first embodiment are steel bars or FRP bars.

[0029] During the preparation of the beam specimen 1 in the first embodiment, the two half-beams 13 are cast simultaneously, and the distance between the wooden molds is ensured to be 50 mm through spacers. After casting, plastic wrap and three-color cloth are covered. After the concrete is formed in 48 hours, the wooden molds are removed and wrapped with burlap for moisture preservation, and water is sprayed for curing every day for 28 days; among them, during the casting and forming process of the half-beam 13, a part of the embedded steel hinge 11 is embedded in the wooden mold at the left position, and the other part of the embedded steel hinge 11 is embedded in the wooden mold at the right position, and the embedded steel hinge 11 is cast integrally with the two half-beams 13; the width × height × length of the beam specimen 1 is 100 mm × 180 mm × 800 mm, and a reinforcing bar 12 with a length of 1000 mm is selected to ensure that the left end and the right end of the reinforcing bar 12 respectively extend to the outside of the beam specimen 1. For the single-mode optical fiber attached to the reinforcing bar 12, the single-mode optical fiber is arranged on the reinforcing bar 12 to measure its strain. The selected single-mode optical fiber is a single-mode optical fiber with a 0.9 mm acrylate coating and a length of 1000 mm. One end is connected to an LC / APC connector. The reinforcing bar 12 reduces its end return loss by means of winding, and the optical fiber is arranged by surface pasting; specifically, first, the pasting section of the reinforcing bar 12 is polished, then the optical fiber with the protective sleeve removed is fixed temporarily with transparent tape after applying a certain pre-tension, 502 glue is evenly applied to the connection between the optical fiber and the reinforcing bar 12, and then the surface is covered and protected with epoxy resin glue. The optical fiber line extending from the beam specimen 1 is bundled at the free end with a tie strap to prevent breakage during handling and casting. It should be noted that the pasting section of the reinforcing bar 12 is the bonding section 15 at the position where the reinforcing bar 12 in the first embodiment is bonded to the half-beam 13, and the single-mode optical fiber is arranged on the reinforcing bar 12 before casting and forming.

[0030] When the beam specimen long-term sustained load test device of the first embodiment works, first, each jack 26 is tensioned to make each jack 26 press downward against the intermediate steel plate 22 on the corresponding side. At this time, the pressure sensor 27 reads the load applied by the jack 26 on the corresponding side. When the pressure value of the pressure sensor 27 reaches the required value, the locking nut 25 is tightened and the position is locked. During this process, the pressure is transmitted to the intermediate steel plate 22, the upper steel pipe 281, the upper beam specimen 1, the intermediate steel pipe 283, the lower beam specimen 1, and the lower steel pipe 282 in sequence. At this time, a four-point bending loading force form is formed on both beam specimens 1.

[0031] It should be emphasized that for the beam specimen long-term sustained load test device of the first embodiment, it can effectively realize the bond-slip test between the reinforcement 12 and the concrete under the long-term sustained load condition in the bending state of the beam, and can also efficiently realize the bond-slip test of two sets of beam specimens 1 at the same time. That is, the beam specimen long-term sustained load test device of the first embodiment has the advantages of structural design.

[0032] Embodiment 2, as Figures 1 to 3 shown, the difference between the second embodiment and the first embodiment is that the two half-beams 13 of the beam specimen 1 are the left half-beam 13 and the right half-beam 13 located on the right end side of the left half-beam 13 in sequence. The part of the reinforcement 12 extending to the left end side of the left half-beam 13 is the left free end 121, the part of the reinforcement 12 extending to the right end side of the right half-beam 13 is the right free end 122, and the part of the reinforcement 12 located between the left half-beam 13 and the right half-beam 13 is the intermediate loading end 123.

[0033] Among them, a first displacement sensor 31 is fixedly installed at the left free end 121 of the reinforcement 12, a second displacement sensor 32 is fixedly installed at the right free end 122 of the reinforcement 12, an induction member 16 is fixedly installed at the intermediate loading end 123 of the reinforcement 12, a third displacement sensor 33 aligned with the induction member 16 is fixedly installed at the right end of the left half-beam 13, and a fourth displacement sensor 34 aligned with the induction member 16 is fixedly installed at the left end of the right half-beam 13.

[0034] It should be explained that the first displacement sensor 31 is fixed to the left free end 121 of the reinforcement 12 by tape adhesion, the second displacement sensor 32 is fixed to the right free end 122 of the reinforcement 12 by tape adhesion, the third displacement sensor 33 is fixed to the left half-beam 13 by tape adhesion, and the fourth displacement sensor 34 is fixed to the right half-beam 13 by tape adhesion.

[0035] For the first displacement sensor 31 in the second embodiment, it is used to record the slip amount of the left free end 121 of the reinforcing member 12 under the load-bearing state; for the second displacement sensor 32 in the second embodiment, it is used to record the slip amount of the right free end 122 of the reinforcing member 12 under the load-bearing state; for the third displacement sensor 33 and the fourth displacement sensor 34 in the second embodiment, they are cooperated with the sensing member 16 and are used to record the slip amount of the loading end of the reinforcing member 12 under the load-bearing state. Therefore, by setting the above-mentioned first displacement sensor 31, second displacement sensor 32, third displacement sensor 33 and fourth displacement sensor 34, the beam specimen long-term load-bearing test device in the second embodiment can be used to record the data of the slip amounts of the loading end and the free end of the reinforcing member 12 under the load-bearing action.

[0036] Embodiment 3, as Figure 3 shown, the difference between this Embodiment 3 and Embodiment 1 is that: the bonding section 15 between the reinforcing member 12 and the half beam 13 is located at the middle position of the corresponding half beam 13, and PVC sleeves 17 are respectively sleeved on both sides of each bonding section 15 of the periphery of the reinforcing member 12.

[0037] At the loading end and the free end of the reinforcing member 12, the reinforcing member 12 is separated from the concrete by PVC sleeves and sealed to ensure that the length of the bonding section 15 remains unchanged; it should be noted that the function of the PVC sleeve is to ensure the length of the bonding section 15 during pouring to prevent concrete from penetrating into the non-bonding section.

[0038] The above content is only the preferred embodiment of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. The content of this specification should not be construed as a limitation to the present invention.

Claims

1. A beam specimen long-term load-holding test device, comprising a beam specimen (1), the beam specimen (1) comprising a pre-buried steel hinge (11), a reinforcing bar (12), and two half-beams (13) arranged opposite to each other and having the same size, a middle gap (14) being provided between the two half-beams (13), and the two half-beams (13) being connected via the pre-buried steel hinge (11); the reinforcing bar (12) and the pre-buried steel hinge (11) being arranged with an interval up and down, the reinforcing bar (12) horizontally passing through the two half-beams (13) in sequence from left to right, the position where the reinforcing bar (12) and the half-beams (13) are bonded is a bonding section (15), and the reinforcing bar (12) is respectively covered with a single-mode optical fiber at the bonding section (15), and the single-mode optical fiber extends to the outside of the half-beam (13); Features: The beam-type specimen long-term load-holding test device comprises two loading assemblies (2) arranged opposite to each other and spaced apart from each other, and two beam-type specimens (1) arranged spaced apart from each other. The loading assembly (2) comprises a lower steel plate (21), an intermediate steel plate (22), and an upper steel plate (23) which are arranged in sequence from bottom to top at intervals. The lower steel plate (21) is provided with two vertical screw rods (24) which are arranged in sequence from front to back and extend vertically respectively. Each vertical screw rod (24) passes through the intermediate steel plate (22) and the upper steel plate (23) in sequence from bottom to top. The upper end of each vertical screw rod (24) is respectively screwed with a locking nut (25) above the upper steel plate (23). A jack (26) and a pressure sensor (27) are provided between the upper steel plate (23) and the intermediate steel plate (22). The upper end of the jack (26) is connected to the upper steel plate (23), and the lower end of the jack (26) is connected to the intermediate steel plate (22) via the pressure sensor (27). The half beam (13) located on the left side of each beam-type specimen (1) is respectively located between the middle steel plate (22) and the lower steel plate (21) of the loading assembly (2) on the left side, and the half beam (13) located on the right side of each beam-type specimen (1) is respectively located between the middle steel plate (22) and the lower steel plate (21) of the loading assembly (2) on the right side; each middle steel plate (22) is in contact with the upper surface of the half beam (13) on the corresponding side of the upper beam-type specimen (1) through the upper steel tube (281), and each lower steel plate (21) is in contact with the lower surface of the half beam (13) on the corresponding side of the lower beam-type specimen (1) through the lower steel tube (282); two middle steel tubes (283) are installed between the upper beam-type specimen (1) and the lower beam-type specimen (1), and the two middle steel tubes (283) are located on both sides of the middle gap (14) of the beam-type specimen (1).

2. A beam specimen long-term load-holding test device according to claim 1, characterized in that: The two half beams (13) of the beam-type specimen (1) are, in sequence, a left half beam (13) and a right half beam (13) located at the right end of the left half beam (13); the portion of the reinforcement (12) extending to the left end of the left half beam (13) is a left free end (121); the portion of the reinforcement (12) extending to the right end of the right half beam (13) is a right free end (122); and the portion of the reinforcement (12) located between the left half beam (13) and the right half beam (13) is an intermediate loading end (123); A first displacement sensor (31) is fastened and mounted on the left free end (121) of the reinforcement (12), a second displacement sensor (32) is fastened and mounted on the right free end (122) of the reinforcement (12), a sensing element (16) is fastened and mounted on the middle loading end (123) of the reinforcement (12), a third displacement sensor (33) aligned with the sensing element (16) is fastened and mounted on the right end of the left half beam (13), and a fourth displacement sensor (34) aligned with the sensing element (16) is fastened and mounted on the left end of the right half beam (13).

3. A beam specimen long-term load-holding test device according to claim 2, characterized in that: The first displacement sensor (31) is fixed to the left free end (121) of the reinforcing bar (12) by adhesive tape, the second displacement sensor (32) is fixed to the right free end (122) of the reinforcing bar (12) by adhesive tape, the third displacement sensor (33) is fixed to the left half beam (13) by adhesive tape, and the fourth displacement sensor (34) is fixed to the right half beam (13) by adhesive tape.

4. A beam specimen long-term load-holding test device according to claim 1, characterized in that: The bonding section (15) between the reinforcement (12) and the half beam (13) is located in the middle of the corresponding half beam (13), and the outer periphery of the reinforcement (12) is respectively provided with PVC sleeves (17) on both sides of each bonding section (15).

5. The long-term load-holding test device for beam-type specimens according to claim 1, characterized in that: The reinforcement material (12) is a steel bar or a FRP bar.

6. A beam specimen long-term load-holding test device according to claim 1, characterized in that: The width of the middle gap (14) is 50 mm.

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