Test device and test method for shear bearing capacity of precast concrete segment joints

Abstract

The present invention provides a precast concrete segment joint shear bearing capacity test device and test method. The test device includes a test bench, a first shear test piece, a second shear test piece, a first load adjustment assembly, a second load adjustment assembly, a first pressure sensor, and a second pressure sensor. The top of the test bench is provided with a groove, the groove including a groove bottom, a first groove wall, and a second groove wall. The groove bottom is arranged horizontally, and the first groove wall and the second groove wall are arranged vertically opposite each other. The first shear portion of the first shear test piece is arranged at the groove bottom, and one side of the first shear portion abuts the first groove wall. The second shear portion of the second shear test piece is placed on top of the first shear portion, and the top surface of the first shear portion and the bottom surface of the second shear portion form a joint surface. The test device can perform shear bearing capacity tests on adhesive joints and dry joint test pieces, can effectively evaluate the shear bearing capacity of precast concrete segment joints, and thus provide scientific guidance for design and construction.

Description

Technical Field

[0001] The present invention relates to the technical field of concrete structure bearing capacity testing, and in particular to a precast concrete segment joint shear bearing capacity testing device and a testing method. Background Art

[0002] Precast concrete segmental beams are typically prefabricated in a prefabrication yard. These segments are then transported to the bridge site for assembly on a bridge-building machine. The segments are then tensioned with longitudinal prestressing tendons to form a single structure. There are three methods for handling the joints between concrete segments during assembly: wet joints, where a 20cm-60cm gap is left between adjacent segments, followed by steel reinforcement and concrete pouring; adhesive joints, where epoxy adhesive is evenly applied to the segment joint interface before assembly, followed by temporary prestressing tendons; and dry joints, where the segments are directly assembled by tensioning temporary prestressing tendons. When calculating the shear capacity of different joint types, there's no difference between segmental beams with wet joints and monolithic beams; the calculation principle is the same, differing only in the construction method. For segmental beams with adhesive or dry joints, the concrete and rebar are discontinuous at the joints, and the joint interface lacks the shear capacity provided by concrete aggregate and ordinary rebar. After the segments are assembled to form the monolithic structure, the large span and stiffness make joint shear capacity testing difficult. Furthermore, since bearing capacity testing is destructive, it's impossible to conduct it on a structure in actual use. To date, it's not possible to effectively assess the shear capacity of precast concrete segmental joints during the design and construction phases. Summary of the Invention

[0003] The present invention aims to solve one of the technical problems existing in the related art. To this end, the present invention proposes a precast concrete segment joint shear bearing capacity testing device. This device can perform shear bearing capacity tests on adhesive joints and dry joint test pieces, effectively assessing the shear bearing capacity of precast concrete segment joints and providing scientific guidance for design and construction.

[0004] An embodiment of the present invention also provides a method for testing the shear bearing capacity of precast concrete segment joints.

[0005] A precast concrete segment joint shear bearing capacity testing device provided in accordance with an embodiment of the first aspect of the present invention comprises:

[0006] A test bench, wherein a groove is provided on the top of the test bench, the groove comprising a groove bottom, a first groove wall and a second groove wall, the groove bottom is arranged horizontally, and the first groove wall and the second groove wall are arranged vertically opposite to each other;

[0007] A first shear test piece includes a first shear portion, wherein the first shear portion is disposed at the bottom of the groove, and one side of the first shear portion abuts against the first groove wall;

[0008] A second shear test piece includes a second shear portion, the second shear portion is placed on top of the first shear portion, and a top surface of the first shear portion and a bottom surface of the second shear portion form a joint surface;

[0009] a first load adjustment assembly connected to the second shear portion, for adjusting the vertical load of the joint surface;

[0010] a second load adjustment assembly, located between the second shearing portion and the second groove wall, for adjusting a horizontal load between the second shearing portion and the first shearing portion;

[0011] a first pressure sensor connected to the second shear portion, for detecting the vertical load;

[0012] The second pressure sensor is connected to a side surface of the second shearing portion and is used to detect the horizontal load.

[0013] According to one embodiment of the present invention, the top surface of the first shearing portion and the bottom surface of the second shearing portion are both planes;

[0014] Alternatively, the top surface of the first shearing portion and the bottom surface of the second shearing portion are both provided with a plurality of shear keys, and the plurality of shear keys on the top surface of the first shearing portion and the plurality of shear keys on the bottom surface of the second shearing portion are staggered.

[0015] According to one embodiment of the present invention, the first shear test piece further includes a first support portion, the first support portion is located between the first shear portion and the first groove wall, and the first support portion and the first shear portion are integrally formed;

[0016] The second shear test piece further includes a second support portion, the second support portion is located between the second shear portion and the second load adjustment assembly, and the second support portion and the second shear portion are integrally formed;

[0017] Wherein, after the first shear test piece and the second shear test piece are butted together, the overall shape is rectangular, and there is a sliding avoidance gap between the first shearing portion and the second supporting portion, as well as between the second shearing portion and the first supporting portion.

[0018] According to one embodiment of the present invention, the first load adjustment component includes:

[0019] a top support member, disposed on the top of the second shearing portion;

[0020] A plurality of vertical tie rods, wherein the plurality of vertical tie rods are connected to the top support member and the test bench, and the plurality of vertical tie rods are evenly and symmetrically arranged;

[0021] A vertical jack is disposed between the top support member and the second shearing portion, and the first pressure sensor is disposed between the top support member and the vertical jack.

[0022] According to one embodiment of the present invention, the second load adjustment assembly includes:

[0023] a transverse jack disposed between the second shearing portion and the second groove wall, and the second pressure sensor is located between the transverse jack and the second shearing portion;

[0024] A plurality of transverse tie rods are connected to the test bench and are evenly distributed on the outside of the transverse jack.

[0025] According to one embodiment of the present invention, both ends of the first pressure sensor and the second pressure sensor are provided with centering supports.

[0026] According to one embodiment of the present invention, leveling supports are provided on the groove bottom, the first groove wall, the second groove wall, the bottom surface of the top support member, the top surface and the side surfaces of the second shearing portion.

[0027] According to one embodiment of the present invention, two parallel leveling support members are provided between the vertical jack and the second shearing portion, and a shear sliding plate is provided between the two leveling support members.

[0028] A method for testing the shear bearing capacity of precast concrete segment joints according to an embodiment of the second aspect of the present invention includes:

[0029] Prefabricate a first shear test piece and a second shear test piece, connect the first shear test piece and the second shear test piece, and then hoist them into a groove of a test bench;

[0030] Install the first load adjustment assembly and the second load adjustment assembly, first adjust the vertical load to a preset load, and then gradually adjust the horizontal load to a maximum load;

[0031] Adjust the preset load and repeat the above steps to obtain multiple sets of vertical loads and multiple sets of maximum loads;

[0032] The shear bearing capacity relationship of the precast concrete segment joint is determined according to the contact area of ​​the first shear test piece and the second shear test piece, the multiple sets of vertical loads, and the multiple sets of maximum loads.

[0033] According to one embodiment of the present invention, the step of connecting the first shear test piece and the second shear test piece specifically includes:

[0034] Applying epoxy adhesive on the top surface of the first shear portion or the bottom surface of the second shear portion, and then butting the first shear test piece and the second shear test piece together;

[0035] The epoxy adhesive, the first shear test piece, and the second shear test piece are allowed to stand for a preset time until they all reach their respective preset strengths.

[0036] According to one embodiment of the present invention, the step of waiting for the epoxy adhesive, the first shear test piece, and the second shear test piece to reach their respective preset strengths further includes:

[0037] applying temporary pressure to the first shear test piece and the second shear test piece;

[0038] The epoxy adhesive, the first shear test piece, and the second shear test piece reach their respective preset strengths under the temporary pressure.

[0039] According to one embodiment of the present invention, the step of prefabricating the first shear test piece and the second shear test piece specifically includes:

[0040] Installing a template according to the position after the first shear test piece and the second shear test piece are butted together, and providing a detachable movable template at the joint surface;

[0041] The second shear test piece is cast first, and after the second shear test piece reaches the strength requirement, the movable formwork is removed, and the first shear test piece is cast by the matching method.

[0042] The above one or more technical solutions in the present invention have at least one of the following technical effects:

[0043] According to an embodiment of the present invention, a precast concrete segment joint shear bearing capacity test device is provided, which includes a test bench, a first shear test piece, a second shear test piece, a first load adjustment assembly, a second load adjustment assembly, a first pressure sensor, and a second pressure sensor; a groove is provided on the top of the test bench, and the groove includes a groove bottom, a first groove wall, and a second groove wall, the groove bottom is arranged horizontally, and the first groove wall and the second groove wall are arranged vertically opposite to each other; the first shear test piece includes a first shear portion, the first shear portion is arranged at the groove bottom, and one side of the first shear portion abuts the first groove wall; the second shear test piece includes a second shear portion, the second shear portion is placed on the top of the first shear portion, and the top surface of the first shear portion and the bottom surface of the second shear portion form a joint surface; the first load adjustment assembly is connected to the second shear portion for adjusting the vertical load on the joint surface; the second load adjustment assembly is located between the second shear portion and the second groove wall, and is used to adjust the horizontal load between the second shear portion and the first shear portion; the first pressure sensor is connected to the second shear portion for detecting the vertical load; and the second pressure sensor is connected to the side of the second shear portion for detecting the horizontal load. The shear bearing capacity testing device for precast concrete segment joints provided by an embodiment of the present invention can perform shear bearing capacity tests on adhesive joints and dry joint test pieces, effectively evaluate the shear bearing capacity of precast concrete segment joints, and provide scientific guidance for design and construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 A schematic structural diagram of a precast concrete segment joint shear bearing capacity testing device provided by an embodiment of the present invention;

[0046] Figure 2 A schematic structural diagram of a shear key adhesive joint test piece provided in an embodiment of the present invention;

[0047] Figure 3 A schematic structural diagram of a flat adhesive joint test piece provided in an embodiment of the present invention;

[0048] Figure 4 A schematic structural diagram of a dry joint test piece with shear keys provided in an embodiment of the present invention;

[0049] Figure 5 A schematic structural diagram of a planar dry joint test piece provided in an embodiment of the present invention;

[0050] Figure 6 Measured data of the test method provided by the embodiment of the present invention Figure 1 ;

[0051] Figure 7 Measured data of the test method provided by the embodiment of the present invention Figure 2 ;

[0052] Figure 8 Measured data of the test method provided by the embodiment of the present invention Figure 3 ;

[0053] Figure 9 Measured data of the test method provided by the embodiment of the present invention Figure 4 .

[0054] Reference numerals:

[0055] 10. Test bench; 11. Groove; 12. First groove wall; 13. Second groove wall;

[0056] 20. First shear test piece; 21. First shear portion; 22. First support portion; 2030. Shear key; 2031. Sliding avoidance gap; 2032. Epoxy adhesive layer;

[0057] 30. Second shear test piece; 31. Second shear portion; 32. Second support portion;

[0058] 40. First load adjustment assembly; 41. Top support member; 42. Vertical tie rod; 43. Vertical jack;

[0059] 50. Second load adjustment assembly; 51. Transverse jack; 52. Transverse tie rod;

[0060] 61. First pressure sensor; 62. Second pressure sensor; 63. Centering support; 64. Leveling support; 65. Shear sliding plate; 66. Centering height adjustment assembly. DETAILED DESCRIPTION

[0061] To make the purpose, technical solutions, and advantages of the invention more clear, the technical solutions of the invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the invention, not all of them. Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the invention.

[0062] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0063] In the description of the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0064] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0065] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0066] The shear bearing capacity testing device for precast concrete segment joints provided by an embodiment of the present invention can prefabricate a first shear test piece and a second shear test piece according to the structure actually used, can simulate adhesive joints and dry joint segment assembly beams, can effectively evaluate the shear bearing capacity of precast concrete segment joints, and can provide scientific guidance for design and construction.

[0067] The shear bearing capacity test device for precast concrete segment joints provided by the first embodiment of the present invention is shown in FIG. Figures 1 to 5 The test apparatus includes a test bench 10 , a first shear test piece 20 , a second shear test piece 30 , a first load adjustment assembly 40 , a second load adjustment assembly 50 , a first pressure sensor 61 , and a second pressure sensor 62 .

[0068] The test bench 10 is a reinforced concrete structure or a steel frame structure. A groove 11 is provided on the top of the test bench 10. The groove 11 includes a groove bottom, a first groove wall 12 and a second groove wall 13. The groove bottom is arranged in the horizontal direction and remains parallel to the bottom of the test bench 10. The first groove wall 12 and the second groove wall 13 are opposite to each other and arranged vertically. The position between the first groove wall 12 and the second groove wall 13 is used to place the first shear test piece 20 and the second shear test piece 30, etc.

[0069] It should be noted that the groove 11 can also be provided on one side of the test bench 10 . Considering the subsequent lifting, installation, reinforcement and other work, the groove 11 is provided on the top of the test bench 10 .

[0070] The first shear test piece 20 includes a first shear portion 21. The first shear test piece 20 is placed between the first groove wall 12 and the second groove wall 13. The first shear portion 21 is placed at the bottom of the groove under the action of its own weight. One side of the first shear portion 21 abuts against the first groove wall 12. Figure 1 The left side of the first shearing portion 21 directly or indirectly abuts against the first groove wall 12 .

[0071] The second shear test piece 30 includes a second shear portion 31, which is placed on top of the first shear portion 21, and the top surface of the first shear portion 21 and the bottom surface of the second shear portion 31 form a joint surface, see Figures 1 to 5 The joint surface can be a plane, or other shear-resistant structures can be set on the plane, for example, a plurality of shear keys 2030 are set on the top surface of the first shear portion 21 and the bottom surface of the second shear portion 31.

[0072] In some embodiments, see Figures 1 to 5The first shear test piece 20 further includes a first support portion 22, which is located between the first shear portion 21 and the first groove wall 12 and is integrally formed with the first shear portion 21. The second shear test piece 30 further includes a second support portion 32, which is located between the second shear portion 31 and the second load adjustment assembly 50 and is integrally formed with the second shear portion 31.

[0073] Among them, the first shear test piece 20 and the second shear test piece 30 are both L-shaped structures, and the overall shape is rectangular after the two are connected, which can simulate the structure and connection state of the concrete segment during actual work. Adjacent concrete segments are spliced ​​together to form a regular beam-column frame connection structure.

[0074] In this embodiment of the present invention, a sliding clearance gap 2031 is defined between the first shear portion 21 and the second support portion 32, and between the second shear portion 31 and the first support portion 22. The sliding clearance gap 2031 provides space for relative sliding movement between the first and second shear test pieces 20 and 30, thereby enabling testing of the shear bearing capacity of the joint surface.

[0075] The first load adjustment assembly 40 is connected to the second shearing section 31 and is used to adjust the vertical load on the joint surface. The first load adjustment assembly 40 can adjust the vertical load by stacking weights or adjusting the thrust of the hydraulic cylinder. The second load adjustment assembly 50 is located between the side of the second shearing section 31 and the second groove wall 13 and is used to adjust the horizontal load between the second shearing section 31 and the first shearing section 21.

[0076] It should be noted that both the first load adjustment assembly 40 and the second load adjustment assembly 50 act on the force center of the component to avoid eccentric force.

[0077] See also Figure 1 The first pressure sensor 61 is connected to the second shearing portion 31 for detecting the vertical load; the second pressure sensor 62 is connected to the side of the second shearing portion 31 for detecting the horizontal load.

[0078] According to the precast concrete segment joint shear bearing capacity test device provided by the embodiment of the present invention, the test bench 10 can position and support the first shear test piece 20 and the second shear test piece 30, the first load adjustment component 40 can simulate the normal compressive stress of the concrete segment joint, and the second load adjustment component 50 can simulate the shear load of the concrete segment joint. The first shear test piece 20 and the second shear test piece 30 are the same proportion or scaled proportionally with the actual precast concrete segment, which can simulate the stress state of the precast concrete segment under actual working conditions. The joint surface between the first shear test piece 20 and the second shear test piece 30 can be a glue joint or a dry joint, so the test device can perform shear bearing capacity tests on glue joints and dry joint test pieces, which can effectively evaluate the shear bearing capacity of precast concrete segment joints and provide scientific guidance for design and construction.

[0079] In one embodiment, see Figure 3 and Figure 5 The top surface of the first shearing portion 21 and the bottom surface of the second shearing portion 31 are both planes. When the maximum load is reached, the first shearing portion 21 and the second shearing portion 31 are marked by relative slippage.

[0080] In another embodiment, see Figure 2 and Figure 4 The top surface of the first shear portion 21 and the bottom surface of the second shear portion 31 are both provided with multiple shear keys 2030. The multiple shear keys 2030 on the top surface of the first shear portion 21 are arranged alternately with the multiple shear keys 2030 on the bottom surface of the second shear portion 31. The multiple shear keys 2030 can increase the resistance to relative sliding between the first shear test piece 20 and the second shear test piece 30. When the maximum load is reached, the appearance of cracks in the shear keys 2030 is a sign.

[0081] According to one embodiment of the present invention, the first load adjustment assembly 40 includes a top support member 41 , a vertical tie rod 42 , and a vertical jack 43 .

[0082] See also Figure 1 A top support member 41 is disposed at the top of the second shearing portion 31. A plurality of vertical tie rods 42 are connected to the top support member 41 and the test bench 10, and the plurality of vertical tie rods 42 are evenly and symmetrically arranged. A vertical jack 43 is disposed between the top support member 41 and the second shearing portion 31, and a first pressure sensor 61 is disposed between the top support member 41 and the vertical jack 43.

[0083] exist Figure 1 In the figure, the multiple vertical pull rods 42 can be steel bars, which are symmetrically distributed on both sides of the vertical jack 43. The two ends of the steel bars can be connected to the test bench 10 and the top support 41 through nuts, etc., to apply reaction force to the vertical jack 43.

[0084] According to one embodiment of the present invention, the second load adjustment assembly 50 includes a transverse jack 51 and a transverse tie rod 52. The transverse jack 51 is disposed between the second shear portion 31 and the second channel wall 13, and the second pressure sensor 62 is located between the transverse jack 51 and the second shear portion 31. Multiple transverse tie rods 52 are connected to the test bench 10 and extend horizontally through the first channel wall 12 and the second channel wall 13. The multiple transverse tie rods 52 are symmetrically distributed on both sides of the transverse jack 51 to maintain force balance on the test bench 10.

[0085] From the above, it can be seen that the first load adjustment component 40 and the second load adjustment component 50 both use jacks to apply loads, and the adjustment of vertical loads and horizontal loads is more flexible and accurate. In addition, the first load adjustment component 40 and the second load adjustment component 50 are small in size, and installation and testing are more convenient.

[0086] According to one embodiment of the present invention, both ends of the first pressure sensor 61 and the second pressure sensor 62 are provided with centering supports 63 .

[0087] See also Figure 1 A centering support 63 is provided at both ends of the first pressure sensor 61 and the second pressure sensor 62. The centering support 63 can evenly transmit the force of the first load adjustment component 40 to the first pressure sensor 61 and the second shear portion 31, and can evenly transmit the force of the second load adjustment component 50 to the side of the second pressure sensor 62 and the second shear portion 31.

[0088] According to one embodiment of the present invention, leveling supports 64 are provided on the groove bottom, the first groove wall 12 , the second groove wall 13 , the bottom surface of the top support member 41 , the top surface and the side surfaces of the second shearing portion 31 .

[0089] See also Figure 1 The test bench 10, the first shear test piece 20 and the second shear test piece 30 are all reinforced concrete components. Each component is made by installing formwork, tying steel bars and pouring concrete. The formwork can ensure the flatness of the surface of the concrete component to a certain extent. However, for the test, it is necessary to further adjust the flatness of each load-bearing surface to avoid uneven force on the test piece due to uneven load-bearing surface.

[0090] In an embodiment of the present invention, the leveling support member 64 can be a leveling steel plate. When installing, the leveling steel plate is not simply attached to the load-bearing surface of the concrete component, but its horizontal angle and vertical angle need to be detected by an instrument to ensure that the stress state of concrete components such as the test bench 10, the first shear test piece 20 and the second shear test piece 30 conforms to the analysis model.

[0091] When the leveling steel plate cannot remain horizontal or vertical, it needs to be polished or pave the load-bearing surface to ensure the horizontality and verticality of the leveling steel plate.

[0092] According to one embodiment of the present invention, two parallel leveling supports 64 are provided between the vertical jack 43 and the second shearing portion 31 , and a shearing sliding plate 65 is provided between the two leveling supports 64 .

[0093] See also Figure 1 After the vertical load is applied, the horizontal load is gradually increased until relative sliding occurs between the first and second shear test pieces 20, 30, or cracks appear at the joint surface. With the shear slip plate 65 installed between the two leveling supports 64, even if relative sliding occurs between the first and second shear test pieces 20, 30, it does not affect the direction of the vertical load, thus improving the directional stability of the vertical load. Furthermore, the frictional resistance between the shear slip plate 65 and the leveling supports 64 is very low, minimally affecting the shear load at the joint and improving the accuracy of the test data.

[0094] The shear bearing capacity test method of precast concrete segment joints provided in accordance with the second embodiment of the present invention includes:

[0095] S100 , prefabricate a first shear test piece and a second shear test piece, connect the first shear test piece and the second shear test piece, and then hoist them into a groove of a test bench.

[0096] S200: Install the first load adjustment assembly and the second load adjustment assembly, first adjust the vertical load to a preset load, and then gradually adjust the horizontal load to a maximum load.

[0097] S300: Adjust the preset load and repeat the above steps to obtain multiple sets of preset loads and multiple sets of maximum loads.

[0098] S400: Determine a shear bearing capacity relationship of a precast concrete segment joint according to a contact area of ​​a first shear test piece and a second shear test piece, a plurality of sets of preset loads, and a plurality of sets of maximum loads.

[0099] In step S100, a first shear test piece 20 and a second shear test piece 30 are prefabricated based on the actual shape and size of the precast concrete segment. The first shear test piece 20 and the second shear test piece 30 can be manufactured to their original size or scaled to a certain ratio. To ensure the reliability of the test data, the concrete strength of the first shear test piece 20 and the second shear test piece 30 must be consistent with that of the precast concrete segment. Furthermore, the first shear test piece 20 and the second shear test piece 30 must be cured to reach a predetermined strength.

[0100] After prefabrication, the first and second shear test pieces 20, 30 need to be connected. For adhesive joint test pieces, epoxy adhesive is applied to the joint interface. Once the epoxy adhesive reaches a predetermined strength, the first and second shear test pieces 20, 30 are hoisted together onto the test bench 10. For dry joint test pieces, the first and second shear test pieces 20, 30 can be butt-jointed and fixed before being hoisted onto the test bench 10, or they can be hoisted separately onto the test bench 10 for docking.

[0101] It should be noted that at least three groups of first shear test pieces 20 and second shear test pieces 30 of each specification should be prefabricated. Multiple groups of test pieces need to be tested to obtain the shear bearing capacity of the joint under different compressive stress levels and their corresponding relationship.

[0102] In step S200, after the first and second shear test pieces 20, 30 are installed, their positions are checked to ensure correct placement and centering accuracy. The vertical load is first adjusted to a preset load, and then the horizontal load is gradually adjusted to the maximum load until relative sliding occurs between the first and second shear test pieces 20, 30 or cracks appear on the joint surface.

[0103] In step S300, the preset load is adjusted, and the above steps are repeated to test the next group of test pieces, so that multiple groups of preset loads and multiple groups of maximum loads can be obtained.

[0104] In step S400, the relationship curve between the load and time of the test piece is recorded by the data acquisition instrument, the maximum load value recorded by the second pressure sensor is obtained (represented by A), and the load value corresponding to the first pressure sensor when the second pressure sensor is at the maximum load is obtained (represented by B). The area of ​​the joint surface of the two test pieces (represented by C) is known, and the actual compressive stress on the joint surface at the limit state is obtained from B / C (represented by D). By testing multiple test pieces under different compressive stresses on the joint surface, multiple groups of A and D can be obtained, and the relationship curve between the shear bearing capacity of the joint (A value) and the compressive stress of the joint surface (D value) can be drawn. The shear bearing capacity calculation formula of the test piece joint can be obtained by the regression equation of the data curve, and the shear bearing capacity of the segmented assembled beam joint can be calculated by this calculation formula.

[0105] According to one embodiment of the present invention, the step of connecting the first shear test piece and the second shear test piece specifically includes:

[0106] S110 , evenly apply epoxy adhesive on the top surface of the first shearing portion or the bottom surface of the second shearing portion, and then butt-join the first shear test piece and the second shear test piece.

[0107] S120 , standing for a preset time, until the epoxy adhesive, the first shear test piece, and the second shear test piece all reach their respective preset strengths.

[0108] In step S110, the epoxy adhesive is evenly applied to the top surface of the first shear portion or the bottom surface of the second shear portion to ensure adhesion between the two. The predetermined standing time is required to ensure that not only the epoxy adhesive reaches a predetermined strength, but also the first and second shear test pieces reach a predetermined strength.

[0109] According to one embodiment of the present invention, the step of waiting for the epoxy adhesive, the first shear test piece, and the second shear test piece to reach their respective preset strengths further includes:

[0110] S121. Apply temporary pressure to the first shear test piece and the second shear test piece.

[0111] S122. The epoxy adhesive, the first shear test piece, and the second shear test piece reach their respective preset strengths under the action of temporary pressure.

[0112] It can be understood that applying temporary pressure to the first shear test piece and the second shear test piece, for example, allowing the epoxy adhesive in the joint to complete curing under a temporary compressive stress of 0.2MPa-0.3MPa, can make the two firmly bonded, avoid the epoxy adhesive shrinkage and cracks, and affect the strength of the adhesive joint.

[0113] According to one embodiment of the present invention, the steps of prefabricating the first shear test piece and the second shear test piece specifically include:

[0114] S101. Install a template according to the position of the first shear test piece and the second shear test piece after they are connected, and set a detachable movable template at the joint surface.

[0115] S102: Cast the second shear test piece first. After the second shear test piece reaches the strength requirement, remove the movable formwork and cast the first shear test piece by the matching method.

[0116] In step S101 and step S102, the first shear test piece and the second shear test piece are cast by the matching method, which can ensure that the first shear test piece and the second shear test piece match each other at different positions of the joint surface, avoid dimensional errors, and reduce the template workload.

[0117] The following are four specific embodiments of the present invention, and the technical solution of the present invention is described in detail with reference to the accompanying drawings.

[0118] Example 1:

[0119] This example is aimed at the shear bearing capacity test of the test specimen with shear key adhesive joint. The test specimen is designed as a reinforced concrete structure with a concrete strength grade of C60. Two shear keys are set on the joint surface, and the area of ​​the joint surface is 0.165m 2 Three groups of test pieces (three first shear test pieces and three second shear test pieces) were prefabricated. Epoxy adhesive was evenly applied to the joint surface. After application, the two shear test pieces were assembled together. A temporary compressive stress of 0.2MPa-0.3MPa was applied to the joint surface in the normal direction and kept stable to allow the epoxy adhesive to cure. See the structural diagram for details. Figure 2 After the concrete strength and epoxy adhesive strength have reached the preset strength, the test piece will be hoisted onto the test bench as a whole, the test equipment will be installed, and the test will be carried out according to the test method for the shear bearing capacity of the adhesive joint. At the test limit state, the actual compressive stresses on the joint surfaces of the three groups of test pieces were 1MPa, 7MPa, and 12.9MPa, respectively, and the measured joint shear bearing capacities were 1140kN, 2388kN, and 3293kN, respectively. The relationship curve of the test results is shown in Figure 2. Figure 6 .

[0120] Example 2:

[0121] This example is aimed at the shear bearing capacity test of the flat adhesive joint test piece. The test piece is designed as a reinforced concrete structure with a concrete strength grade of C60 and a flat joint surface with an area of ​​0.165m 2 Three groups of test pieces were prefabricated. Epoxy adhesive was evenly applied to the joint interface of the test pieces. After application, the other half of the test pieces were assembled together. A temporary compressive stress of 0.2MPa-0.3MPa was applied to the joint surface and kept stable to allow the epoxy adhesive to cure. See the structural diagram for details. Figure 3 After the concrete strength and epoxy adhesive strength have reached the preset strength, the test piece will be hoisted onto the test rig as a whole, the test equipment will be installed, and the test will be carried out according to the test method for the shear bearing capacity of adhesive joints. At the test limit state, the actual compressive stresses on the joint surfaces of the three groups of test pieces were 1MPa, 7MPa, and 13MPa, respectively, and the measured joint shear bearing capacities were 908kN, 1896kN, and 2916kN, respectively. The relationship curve of the test results is shown in Figure 2. Figure 7 .

[0122] Example 3:

[0123] This example is aimed at the shear bearing capacity test of dry joint test specimens with shear keys. The test specimen is designed as a reinforced concrete structure with a concrete strength grade of C50. Two shear keys are set on the joint surface, and the area of ​​the joint surface is 0.144m 2 Three groups of test pieces were prefabricated for the test. See the structural diagram for details. Figure 4After the concrete strength reaches the preset strength, the test piece is hoisted onto the test pedestal, the test equipment is installed, and the test is carried out according to the dry joint shear bearing capacity test method. At the test limit state, the actual compressive stresses on the joint surfaces of the three groups of test pieces are 8.2MPa, 12.1MPa, and 14.8MPa, respectively, and the measured joint shear bearing capacities are 1614kN, 1814kN, and 1914kN, respectively. The relationship curve of the test results is shown in Figure 2. Figure 8 .

[0124] Example 4:

[0125] This example is aimed at the shear bearing capacity test of the plane dry joint test piece. The test piece is designed as a reinforced concrete structure with a concrete strength grade of C50 and a plane joint surface with an area of ​​0.144m 2 Three groups of test pieces were prefabricated for the test. See the structural diagram for details. Figure 5 After the concrete strength reaches the preset strength, the test piece is hoisted onto the test pedestal, the test equipment is installed, and the test is carried out according to the dry joint shear bearing capacity test method. At the test limit state, the actual compressive stresses on the joint surfaces of the three groups of test pieces are 8.2MPa, 12.1MPa, and 14.8MPa, respectively, and the measured joint shear bearing capacities are 709kN, 1045kN, and 1279kN, respectively. The relationship curve of the test results is shown in Figure 2. Figure 9 .

[0126] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A precast concrete segment joint shear bearing capacity test device, characterized in that: include: A test bench, wherein a groove is provided on the top of the test bench, the groove comprising a groove bottom, a first groove wall and a second groove wall, the groove bottom is arranged horizontally, and the first groove wall and the second groove wall are arranged vertically opposite to each other; A first shear test piece includes a first shear portion, wherein the first shear portion is disposed at the bottom of the groove, and one side of the first shear portion abuts against the first groove wall; A second shear test piece includes a second shear portion, the second shear portion is placed on top of the first shear portion, and a top surface of the first shear portion and a bottom surface of the second shear portion form a joint surface; a first load adjustment assembly connected to the second shear portion, for adjusting the vertical load at the joint surface; a second load adjustment assembly, located between the second shearing portion and the second groove wall, for adjusting a horizontal load between the second shearing portion and the first shearing portion; a first pressure sensor connected to the second shear portion, for detecting the vertical load; a second pressure sensor connected to a side surface of the second shearing portion, for detecting the horizontal load; The top surface of the first shearing portion and the bottom surface of the second shearing portion are both planes; Alternatively, a plurality of shear keys are provided on the top surface of the first shear portion and the bottom surface of the second shear portion, and the plurality of shear keys on the top surface of the first shear portion and the plurality of shear keys on the bottom surface of the second shear portion are staggered. The first shear test piece further includes a first support portion, the first support portion is located between the first shear portion and the first groove wall, and the first support portion and the first shear portion are integrally formed; The second shear test piece further includes a second support portion, the second support portion is located between the second shear portion and the second load adjustment assembly, and the second support portion and the second shear portion are integrally formed; Wherein, after the first shear test piece and the second shear test piece are butted together, the overall shape is rectangular, and there is a sliding avoidance gap between the first shearing portion and the second supporting portion, as well as between the second shearing portion and the first supporting portion.

2. The shear bearing capacity testing device for precast concrete segment joints according to claim 1 is characterized in that: The first load adjustment component includes: a top support member, disposed on the top of the second shearing portion; A plurality of vertical tie rods, wherein the plurality of vertical tie rods are connected to the top support member and the test bench, and the plurality of vertical tie rods are evenly and symmetrically arranged; A vertical jack is disposed between the top support member and the second shearing portion, and the first pressure sensor is disposed between the top support member and the vertical jack.

3. The shear bearing capacity testing device for precast concrete segment joints according to claim 2 is characterized in that: The second load adjustment assembly includes: a transverse jack disposed between the second shearing portion and the second groove wall, and the second pressure sensor is located between the transverse jack and the second shearing portion; A plurality of transverse tie rods are connected to the test bench and are evenly distributed on the outside of the transverse jack.

4. The precast concrete segment joint shear bearing capacity testing device according to claim 3, characterized in that: Leveling supports are provided on the groove bottom, the first groove wall, the second groove wall, the bottom surface of the top support member, the top surface and the side surfaces of the second shearing portion.

5. The precast concrete segment joint shear bearing capacity testing device according to claim 4, characterized in that: Two parallel leveling support members are provided between the vertical jack and the second shearing portion, and a shearing sliding plate is provided between the two leveling support members.

6. A test method for the shear bearing capacity test device of precast concrete segment joints according to any one of claims 1 to 5, characterized in that: include: Prefabricate a first shear test piece and a second shear test piece, connect the first shear test piece and the second shear test piece, and then hoist them into a groove of a test bench; Install the first load adjustment assembly and the second load adjustment assembly, first adjust the vertical load to a preset load, and then gradually adjust the horizontal load to a maximum load; Adjust the preset load and repeat the above steps to obtain multiple sets of the preset loads and multiple sets of the maximum loads; The shear bearing capacity relationship of the precast concrete segment joint is determined according to the contact area of ​​the first shear test piece and the second shear test piece, the multiple sets of vertical loads, and the multiple sets of maximum loads.

7. The shear bearing capacity test method for precast concrete segment joints according to claim 6, characterized in that: The step of connecting the first shear test piece and the second shear test piece specifically includes: Applying epoxy adhesive on the top surface of the first shear portion or the bottom surface of the second shear portion, and then butting the first shear test piece and the second shear test piece together; The epoxy adhesive, the first shear test piece, and the second shear test piece are allowed to stand for a preset time until they all reach their respective preset strengths.

8. The shear bearing capacity test method for precast concrete segment joints according to claim 7, characterized in that: The step of waiting for the epoxy adhesive, the first shear test piece, and the second shear test piece to reach their respective preset strengths further includes: applying temporary pressure to the first shear test piece and the second shear test piece; The epoxy adhesive, the first shear test piece, and the second shear test piece reach their respective preset strengths under the action of the temporary pressure.

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