Grouting metal corrugated pipe with key teeth for steel bar anchoring

Abstract

A grouting metal corrugated pipe with key teeth for steel bar anchoring comprises a corrugated pipe body and the key teeth located at wave troughs of the outer wall of the corrugated pipe body. The bottom of the corrugated pipe main body is closed, the top of the corrugated pipe main body is open, the opening is used for inserting a reinforcing steel bar extending from an adjacent connecting component, and the reinforcing steel bar inserted into the opening and the corrugated pipe main body form reliable anchoring through a grouting material; the key teeth are in a semi-conical shape, a double-semi-conical shape or a semi-cylindrical shape; the key teeth and the corrugated pipe main body are connected together through integral casting processing, welding or a connecting piece; when the corrugated pipe structure with the key teeth is used for grouting corrugated pipe connection, the bonding and anchoring performance of the corrugated pipe and common concrete can be improved, the problem of stress concentration is effectively solved, the anchoring length of the corrugated pipe is reduced, and the problem that when high-performance grouting materials are used, the service life of the corrugated pipe is prolonged is solved. And in addition, the structure and the method are simple in process, and the arrangement position is flexible.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of prefabricated assembly bridges, and in particular to a grouting metal bellows with key teeth for reinforcing steel anchoring. BACKGROUND

[0002] With the concept of bridge prefabricated assembly expanding from the superstructure to the substructure, the range of prefabricated components also gradually covers the main prefabricated assembly pier beam consolidation beam, cap beam, pier column and other main bridge force components. As the key part of the prefabricated bridge, the reliability of its connection determines the reliability of the bridge, so the connection performance of the pier should be paid special attention. In addition, the bonding effect between concrete and steel increases with the increase of concrete strength, and the excellent mechanical properties and good self-compacting properties of ultra-high performance concrete (UHPC) can increase the gripping effect of concrete on steel and reduce the required anchoring length.

[0003] The currently commonly used prefabricated assembly pier column connection methods mainly include grouting bellows connection, etc. For example, the patent application with publication number CN112195753A discloses a grouting metal bellows for reinforcing steel anchoring, which can be used for prefabricated assembly pier column connection. However, the structure has the following deficiencies that need to be solved urgently: the connection length control interface of the UHPC grouting bellows connection is the interface between the bellows and the surrounding ordinary concrete. Specifically, the excellent bonding performance between UHPC and steel makes the steel anchoring length shorter, and the lower bonding strength between the bellows and the ordinary concrete makes the bellows anchoring length longer. SUMMARY

[0004] In order to overcome the defects of the prior art, the purpose of the present application is to provide a grouting metal bellows with key teeth for reinforcing steel anchoring, which improves the anchoring strength of the bellows with the surrounding concrete by setting key teeth at the trough position of the bellows, reduces the length of the bellows required to meet the performance requirements, and makes the anchoring length of the bellows in UHPC compatible with the anchoring length of the steel in UHPC, so as to achieve the purpose of meeting the performance standards and having economic advantages, thereby solving the problems of excessive anchoring length of the grouting bellows in ordinary concrete and the incompatible anchoring length of the bellows with the steel in UHPC.

[0005] The above technical purpose of the present application is achieved by the following technical scheme:

[0006] A grouting metal bellows with key teeth for reinforcing steel anchoring, comprising a bellows body 3 and key teeth 6 located at the trough of the outer wall of the bellows body 3.

[0007] The bottom of the bellows body 3 is closed, and the top is open. The opening is used for inserting the steel bars 7 protruding from the adjacent connecting component 1, and the steel bars 7 inserted into the opening form reliable anchoring with the bellows body 3 through grouting material 4.

[0008] The connection between the key tooth 6 and the bellows body 3 is integrally cast, welded or connected by a connecting piece.

[0009] When the key tooth 6 and the bellows body 3 are connected by a connecting piece, the connecting piece includes a pin key 13 or a bolt 10, and when the bolt is used, the connecting piece further includes a split connection and an integral connection.

[0010] The split connection includes that the inner thread of the key tooth body 11 of the key tooth 6 is screwed with one end of the bolt 10, the other end of the bolt 10 passes through the hole in the bellows body 3 where the key tooth 6 is to be arranged, and then the split positioning block 8 and the nut 9 are screwed from the inside of the pipe.

[0011] The integral connection includes that the key tooth body 11 of the key tooth 6 is integrally designed with the positioning block 8.

[0012] When the connecting piece is a pin key, the specific structure includes that the key tooth 6 includes an integrally designed key tooth body 11, a positioning block 8 and a pin shaft 12, the pin shaft 12 is provided with a hole for inserting the pin key 13, and after the pin shaft 12 passes through the hole in the bellows body 3 where the key tooth 6 is to be arranged, i.e. after the pin shaft 12 passes through the wall of the bellows body 3, the pin key 13 is inserted into the pin shaft 12.

[0013] The inner and outer walls of the bellows body 3 are arranged in a regular corrugated shape, the wall thickness is not less than 2 mm, the wave height is not less than 3 mm, the wave distance is not greater than 32 mm and not less than 30 mm, and the material is a steel material with a strength of not less than 235 MPa.

[0014] The key tooth 6 is located at the wave trough of the outer wall of the bellows body 3 and is uniformly distributed along the same position, the shape of the key tooth 6 is similar to the reverse direction of the stress diffusion angle of the local compression of the concrete in contact with the key tooth 6, and includes a half-cone shape, a double half-cone shape or a half-cylinder shape.

[0015] The material strength of the key tooth 6 is higher than the strength of the bellows, and 316L stainless steel or a material with a yield strength of more than 400 MPa is used to make the key tooth 6 by 3D printing or casting.

[0016] Compared with the prior art, the beneficial effects of the present application are:

[0017] (1) The corrugated pipe with key teeth structure provided by the application can improve the bonding anchoring performance of the corrugated pipe and ordinary concrete when the corrugated pipe is connected by using the structure, thereby reducing the anchoring length of the corrugated pipe in the concrete, that is, when the anchoring length of the corrugated pipe is adapted to the anchoring length of the steel bar, the corrugated pipe without key teeth will be pulled out due to bonding failure, and the structure provided by the application can effectively improve the stress concentration problem, thereby achieving the purpose of reducing the anchoring length. The waste problem caused by the mismatch between the short anchoring length between the required steel bar and the grouting material and the long anchoring length of the corrugated pipe in the concrete is solved, and the structure has certain economy.

[0018] (2) The key tooth structure provided by the application is similar to the reverse direction of the stress diffusion angle of the local compression of the concrete in contact with the key tooth, the stress of the key tooth is reasonable, the stress concentration effect of the connection between the key tooth and the main body of the corrugated pipe is reduced, and the force transmitted along the radial center of the corrugated pipe further enhances the constraint of the grouting material on the anchoring steel bar and the grouting material on the anchoring steel bar, so that the whole structure is more reasonable and reliable in stress.

[0019] In summary, the key tooth structure provided by the application has the advantages of simple manufacturing process, flexible setting position, and flexible setting mode and quantity according to the use requirements. The anchoring strength of the key tooth structure and the surrounding concrete is improved, the length of the corrugated pipe required to achieve the performance requirement is reduced, and the problems of the long anchoring length of the grouting corrugated pipe in the ordinary concrete and the mismatch between the anchoring length of the corrugated pipe and the steel bar in the UHPC are solved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a schematic diagram of a prefabricated assembly type pier structure.

[0021] Fig. 2(a) is an axial side view of the bottom surface of the grouting corrugated pipe with key teeth, Fig. 2(b) is an axial side view of the top surface of the grouting corrugated pipe with key teeth, and Fig. 2(c) is an isometric view of the connection joint of the grouting corrugated pipe with key teeth.

[0022] Figure 3 is a finite element model of the connection joint of the grouting corrugated pipe with key teeth.

[0023] Figure 4 is a schematic diagram of the bolt connection between the key tooth and the main body of the corrugated pipe, wherein Figure 4 (a) in Fig. 2(c) is an axial side view, Figure 4 (b) in Fig. 2(c) is a front view.

[0024] Figure 5 is Figure 4 the schematic diagram of the integral setting of the key tooth main body and the positioning block, wherein Figure 5 (a) in Fig. 2(c) is an axial side view, Figure 5 (b) in Fig. 2(c) is a front view.

[0025] Figure 6 is the schematic diagram of the connection between the key tooth and the corrugated pipe body by pin key, wherein Figure 6 (a) in is the axial side view, Figure 6 (b) in is the front view.

[0026] In the figure: 1, adjacent connecting member, 2, ordinary concrete, 3, corrugated pipe body, 4, UHPC, 5, stirrup, 6, key tooth, 7, steel bar, 8, positioning block, 9, nut, 10, bolt, 11, key tooth body, 12, pin shaft, 13, pin key. DETAILED DESCRIPTION

[0027] The application will be described in detail below in combination with the drawings and specific embodiments.

[0028] As Figure 1 , Figures 2(a)-2(c) shown, a steel bar anchoring grouting metal corrugated pipe with key tooth includes a corrugated pipe body 3 and a key tooth 6 located at the valley of the outer wall of the corrugated pipe body 3.

[0029] The bottom of the corrugated pipe body 3 is closed, and the top is open, the opening is used for inserting the steel bar 7 on the adjacent connecting member 1, the steel bar 7 inserted into the opening forms reliable anchoring with the corrugated pipe body 3 through grouting material 4, the corrugated pipe body 3 is embedded in concrete 2, when the adjacent connecting member 1 on the steel bar 7 transmits force, the corrugated pipe body 3 and the key tooth 6 jointly bear the force, through the stress dispersion effect of the key tooth, the bonding anchoring performance between the corrugated pipe body 3 and the concrete 2 is improved, and the required anchoring length of the corrugated pipe body 3 in the concrete 2 can be reduced.

[0030] The connection mode between the key tooth 6 and the corrugated pipe body 3 is integrally cast, welded, or assembled and fastened by a pin key connecting piece or a bolt connecting piece.

[0031] When the key tooth 6 and the corrugated pipe body 3 are connected by the connecting piece, the connecting piece includes a pin key 13 or a bolt 10, and when the bolt is connected, it further includes a separate connection and an integral connection.

[0032] Referring to Figure 4 , the specific structure of the separate connection is that the inner thread of the key tooth body 11 of the key tooth 6 is screwed with one end of the bolt 10, after the other end of the bolt 10 passes through the hole on the corrugated pipe body 3 where the key tooth 6 is to be arranged, the bolt 10 is tightened from the inside of the pipe through the separate positioning block 8 and the nut 9, and when the bolt 10 is screwed into the separate positioning block 8 and the nut 9, the key tooth body 11 and the corrugated pipe body 3 are integrated.

[0033] Referring to Figure 5The key tooth 6 is integrally designed with the positioning block 8, the inner thread of the key tooth body 11 is screwed with one end of the bolt 10, the other end of the bolt 10 passes through the hole in the corrugated pipe body 3 where the key tooth 6 is to be arranged, and then the bolt is screwed with the corrugated pipe body 3 through the nut 9 from the pipe, so that the key tooth body 11 and the corrugated pipe body 3 are connected as a whole.

[0034] Referring to Figure 6 When the connecting piece adopts a pin key, the specific structure is that the key tooth 6 includes an integrally designed key tooth body 11, a positioning block 8 and a pin shaft 12, the pin shaft 12 is provided with a hole for inserting the pin key 13, the pin shaft 12 passes through the hole in the corrugated pipe body 3 where the key tooth 6 is to be arranged, that is, the pin shaft 12 passes through the pipe wall of the corrugated pipe body 3, and then the pin key 13 is inserted into the pin shaft 12, so that the key tooth body 11 and the corrugated pipe body 3 are connected as a whole.

[0035] Further, the inner and outer walls of the corrugated pipe body 3 are arranged in a regular corrugated shape, the wall thickness is not less than 2 mm, the wave height is not less than 3 mm, the wave distance is not greater than 32 mm and not less than 30 mm, and the material is a steel material with a strength not less than 235 MPa.

[0036] Further, the key tooth 6 is located at the wave trough of the outer wall of the corrugated pipe body 3 and is uniformly distributed along the same position, so that the relative position of the corrugated pipe body 3 and the external stirrup 5 in the actual engineering is not affected, and the anchoring length of the corrugated pipe body 3 in the concrete 2 is reduced. The shape of the key tooth 6 is similar to the reverse direction of the stress diffusion angle of the local compression of the concrete in contact with the key tooth, including a half circular cone shape, a double half circular cone shape or a half circular cylinder shape, and the reason why the shape of the key tooth 6 is similar to the reverse direction of the stress diffusion angle of the local compression of the concrete 2 in contact with the key tooth is that the key tooth is reasonably stressed, the stress concentration effect at the connection between the key tooth and the corrugated pipe body is reduced, the overall structural stress is more reasonable, and the structure is more reliable.

[0037] Further, the key tooth 6 has a higher material strength than the corrugated pipe, is made of 316L stainless steel or a material with a yield strength exceeding 400 MPa through 3D printing or casting, and has a higher strength than the corrugated pipe, so that the bonding and anchoring performance between the corrugated pipe body and the concrete can be improved in use.

[0038] There are mainly three kinds of processing methods for the key tooth 6 and the corrugated pipe body 3:

[0039] The first processing method is to fix the key tooth 6 and the corrugated pipe body 3 by using a bolt connection mode, which specifically includes the following steps:

[0040] S1: The corrugated pipe body 3 is processed and formed;

[0041] S2: opening a hole on the outer wall of the wave trough at the position of the preset key tooth 6 on the corrugated pipe body 3;

[0042] S3: fixing the processed key tooth 6 in the hole opened by S2 on the outer wall of the wave trough of the corrugated pipe body 3 by bolt connection;

[0043] S3 specifically includes the following contents:

[0044] S3-1: when the separated bolt connection mode is adopted, the bolt 10 is first connected with the inner thread of the key tooth body 11, then the bolt 10 is inserted through the outer wall of the wave trough of the corrugated pipe body 3, and finally the positioning block 8 and the nut 9 are screwed into the bolt 10 from the inside of the corrugated pipe body 3, so that the key tooth body 11 and the corrugated pipe body 3 are connected as a whole.

[0045] S3-2: when the integrated bolt connection mode is adopted, the key tooth body 11 and the positioning block 8 are integrally processed, the key tooth body 11 with the positioning block 8 is first connected with the bolt 10, then the bolt 10 is inserted through the outer wall of the wave trough of the corrugated pipe body 3, and finally the nut 9 is screwed into the bolt 10 from the inside of the corrugated pipe body 3, so that the key tooth body 11 and the corrugated pipe body 3 are connected as a whole.

[0046] The second processing method is to fix the key tooth 6 and the corrugated pipe body 3 by using the pin key connection mode, which specifically includes the following steps:

[0047] S1: the corrugated pipe body 3 is processed and formed;

[0048] S2: opening a hole on the outer wall of the wave trough at the position of the preset key tooth on the corrugated pipe body 3;

[0049] S3: the key tooth body 11, the positioning block 8 and the pin shaft 12 are integrally processed, the pin shaft 12 is inserted through the outer wall of the wave trough of the corrugated pipe body 3, and the pin key 13 is inserted into the reserved hole of the pin shaft 12 from the inside of the corrugated pipe body 3, so that the key tooth body 11 and the corrugated pipe body 3 are connected as a whole.

[0050] The third processing method is to fix the key tooth 6 and the corrugated pipe body 3 by using the welding mode, which specifically includes the following steps:

[0051] S1: the corrugated pipe body 3 is processed and formed;

[0052] S2: fixing the key tooth on the outer wall of the wave trough of the corrugated pipe by welding at the position of the preset key tooth on the corrugated pipe body 3;

[0053] In order to explore the setting effect of key teeth and optimize the parameters, in the case of 316L stainless steel semi-cone key teeth, the finite element calculation and analysis of unilateral pulling test were carried out on the position of key teeth setting in the joint specimen of 40mm diameter HRB400 steel bar, and the test verification was carried out, and the finite element model and the test specimen structure are shown in Figure 3

[0054] The specific parameters of each group are shown in Table 1, and the surrounding concrete stress, corrugated pipe stress and key tooth stress of the finite element model are compared and analyzed under the ultimate state of steel bar stress of 710MPa. As shown in Table 2, the results show that when the corrugated pipe is not provided with key teeth, the outer concrete compressive stress shows a decreasing trend from the pulling side to the free side, the maximum compressive stress is distributed within 110mm range from the pulling side end surface, and the outer concrete near the corrugated pipe within 10mm range from the pulling side end surface will appear concrete stress concentration, with a peak value of 22.06MPa; the test results show that the corrugated pipe without key teeth will appear pulling out due to the failure of surrounding concrete constraint under the construction length ensuring the failure mode of steel bar fracture. Setting key teeth at the corrugated pipe valley on the pulling side (b, c, d, e groups) can reduce the maximum compressive stress distribution length of the concrete pulling end by about 50%, but will intensify the stress concentration phenomenon of the adjacent pulling side outer concrete, and there is a hidden danger of concrete crushing; setting key teeth at the free side of the corrugated pipe (g, h, i groups) can also reduce the maximum compressive stress distribution length of the concrete pulling end by about 50%, and can eliminate the stress concentration phenomenon of the pulling side end surface concrete; but there is a large tensile stress on the free side, and there is a hidden danger of concrete cracking. On the basis of the above two schemes, adjusting the setting position of key teeth, setting one layer of key teeth at the middle and free side of the corrugated pipe can not only eliminate the stress concentration phenomenon of the pulling side concrete, reduce the peak value of the outer concrete compressive stress, but also retain the effect of reducing the maximum compressive stress distribution length of the concrete pulling end; in addition, the peak value of the free side tensile stress is also greatly reduced, effectively avoiding the phenomenon of concrete tensile cracking. The pulling failure in the test results is the synchronous development of the compression cracks at the pulling end and the tensile cracks at the free end, and finally penetrates through the side surface of the specimen, so that the surrounding concrete constraint fails and the corrugated pipe is pulled out; setting key teeth on the corrugated pipe can effectively improve the concrete stress concentration and cracking damage phenomenon at the pulling end and free end of the corrugated pipe by reasonably setting the position of the key teeth, and finally achieve the purpose of reducing the anchorage length of the corrugated pipe.

[0055] Table 1 Setting overview of each group of finite element models

[0056]

[0057]

[0058] Table 2 Comparison of results of each group of finite element models ​

[0059]

[0060] In summary, compared with the conventional corrugated pipe without key teeth, the reasonable setting of key teeth can effectively improve the stress concentration and cracking damage of concrete and reduce the anchorage length of the corrugated pipe; through the finite element simulation analysis, it is concluded that the setting of key teeth in the middle and free side trough of the corrugated pipe is the optimal scheme.

[0061] Although the specification is described in terms of embodiments, it does not contain only one independent technical solution, and the specification is described in this way only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in the examples can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A grouting metal corrugated pipe for reinforcing bar anchoring with key teeth, characterized by, The corrugated pipe body (3) is closed at the bottom and open at the top, and the opening is used for inserting the steel bars (7) protruding from the adjacent connecting member (1), and the steel bars (7) inserted into the opening are reliably anchored with the corrugated pipe body (3) by grouting material (4). The connection between the key tooth (6) and the corrugated pipe body (3) is integrally cast, welded or connected by a connecting piece.

2. A grouting metal bellows for reinforcing bar anchoring with key teeth according to claim 1, characterized in that, When the key tooth (6) and the corrugated pipe body (3) are connected by a connecting piece, the connecting piece includes a pin key (13) or a bolt (10), and when the bolt is used for connection, it includes a separate connection and an integral connection.

3. A grouting metal bellows for reinforcing bar anchoring with key teeth according to claim 2, characterized in that, The separate connection has the following specific structure: the inner thread of the key tooth body (11) of the key tooth (6) is connected with one end of the bolt (10), the other end of the bolt (10) passes through the hole in the corrugated pipe body (3) where the key tooth (6) is to be arranged, and then is tightened from the inside of the pipe by the separate positioning block (8) and the nut (9).

4. A grouting metal bellows for reinforcing bar anchoring with key teeth according to claim 3, characterized in that, The integral connection has the following specific structure: the key tooth body (11) of the key tooth (6) is designed in an integral manner with the positioning block (8).

5. A grouting metal bellows for reinforcing bar anchoring with key teeth according to claim 4, characterized in that, When the connecting piece is a pin key, the specific structure is that the key tooth (6) includes an integrally designed key tooth body (11), a positioning block (8) and a pin shaft (12), the pin shaft (12) has a hole for inserting the pin key (13), and after the pin shaft (12) passes through the hole in the corrugated pipe body (3) where the key tooth (6) is to be arranged, the pin key (13) is inserted into the pin shaft (12).

6. A grout-filled metal corrugated pipe with key teeth for anchoring reinforcement according to claim 3, characterized in that, The inner and outer walls of the corrugated pipe body (3) are arranged in a regular corrugated shape, the wall thickness is not less than 2mm, the wave height is not less than 3mm, the wave distance is not greater than 32mm and not less than 30mm, and the material is a steel material with a strength not less than 235MPa.

7. A grout-filled metal corrugated pipe with key teeth for anchoring reinforcement according to claim 1, characterized in that, The key tooth (6) is located at the wave trough of the outer wall of the corrugated pipe body (3) and is uniformly distributed along the same position, and the shape of the key tooth (6) is similar to the reverse direction of the stress diffusion angle of the local compression of the concrete in contact with the key tooth (6), including a semicircular cone, a double semicircular cone or a semicircular cylinder.

8. A grout-filled metal corrugated pipe with key teeth for anchoring reinforcement according to claim 1, characterized in that, The key tooth (6) has a higher material strength than the corrugated pipe, and is made of 316L stainless steel or a material with a yield strength exceeding 400MPa by 3D printing or casting.

9. A grout-filled metal corrugated pipe with key teeth for anchoring reinforcement according to claim 1, characterized in that, ​

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