A connecting structure between prefabricated hollow pier columns of a bridge and a construction method

Abstract

The application provides a connecting structure between prefabricated hollow pier columns of a bridge and a construction method. An inner sleeve is embedded in the lower end of an upper hollow pier column, the inner sleeve is provided with an inner sleeve transverse partition plate, and the inner sleeve is provided with a grout inlet slot below the inner sleeve transverse partition plate. An outer sleeve is embedded in the upper end of a lower hollow pier column, and the upper end of the lower hollow pier column is provided with an end transverse partition plate. After the upper hollow pier column and the lower hollow pier column are butted, the lower section of the inner sleeve is inserted into the upper section of the outer sleeve to form a ring-shaped first pouring cavity, the first shear key of the lower section of the inner sleeve and the third shear key of the upper section of the outer sleeve are both located in the first pouring cavity, and the main reinforcement in the upper hollow pier column and the lower hollow pier column both extend into the first pouring cavity. The inner sleeve transverse partition plate is located above the end transverse partition plate and forms a third pouring cavity, and the grout inlet slot communicates the first pouring cavity and the third pouring cavity. The application can realize reliable connection between pier columns, has the same connection effect as cast-in-place connection, and has certain toughness and seismic resistance.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, specifically to a connection structure and construction method between precast hollow bridge piers. Background Technology

[0002] In the field of bridge and building engineering, prefabrication and assembly technology has been widely used in connection nodes such as piers and cap beams, and piers and pile caps or pile foundations. Among these, the connection technology between piers and pile caps or pile foundations is relatively mature, forming various connection forms such as socket connections, grouting corrugated pipe connections, and grouting sleeve connections. Since pile foundations and pile caps, as the basic components connecting piers and the ground, are usually constructed above ground level, effectively avoiding the construction difficulties caused by working at heights. Furthermore, thanks to the structural dimensional advantages of pile foundations and pile caps, the dimensions of their connection points can be designed to be larger than the superstructure, providing ample connection space for pier installation. Moreover, the abrupt change in cross-section is itself a structural design feature, so there is no need to specifically consider the abrupt change in cross-section at the connection node.

[0003] However, for pier components, the current construction method still predominantly employs integral prefabrication, transportation, and hoisting. Limited by transportation conditions and the load-bearing capacity of hoisting equipment, the geometric dimensions of prefabricated piers are severely constrained. More critically, in terms of the technical difficulty of connecting prefabricated components, a technical gradient emerges: pier-to-pier connection > pier-to-cap beam connection > pier-to-pile cap or pile foundation connection. Existing pier-to-cap beam and pier-to-pile cap or pile foundation connection technologies cannot be directly applied to pier-to-pier connections. This technical bottleneck severely restricts the widespread application of prefabrication and assembly technology in pier construction.

[0004] In summary, there is an urgent need for a connection structure and construction method between precast hollow bridge piers to solve the problems existing in the current technology. Summary of the Invention

[0005] The purpose of this invention is to provide a connection structure between prefabricated hollow bridge piers, aiming to solve the problem that the lack of an effective connection structure between piers in existing technologies limits the prefabrication and assembly technology of bridge piers. The specific technical solution is as follows:

[0006] A connection structure between prefabricated hollow bridge piers includes an upper hollow pier, an inner sleeve, a lower hollow pier, and an outer sleeve.

[0007] The inner sleeve is provided with a first shear key, and the inner sleeve is embedded in the lower end of the upper hollow pier through the first shear key in its upper section. The inner sleeve is provided with an inner tube diaphragm, and multiple grout inlets are provided circumferentially at intervals on the side wall of the inner sleeve below the inner tube diaphragm. The outer sleeve is provided with a third shear key, and the outer sleeve is embedded in the upper end of the lower hollow pier through the third shear key in its lower section. The upper end of the lower hollow pier is provided with an end diaphragm.

[0008] After the upper hollow pier column and the lower hollow pier column are connected, the lower section of the inner sleeve is inserted into the upper section of the outer sleeve, and the two form an annular first casting cavity. The first shear key of the lower section of the inner sleeve and the third shear key of the upper section of the outer sleeve are both located in the first casting cavity. The upper main reinforcement in the upper hollow pier column and the lower main reinforcement in the lower hollow pier column extend into the first casting cavity, and the upper main reinforcement and the lower main reinforcement are overlapped. The inner diaphragm is located above the end diaphragm, and the two form a third casting cavity. The grout inlet connects the first casting cavity and the third casting cavity.

[0009] Preferably, the upper hollow pier is provided with grouting holes and grout outlet holes. The grouting holes and grout outlet holes are both inclined and symmetrically arranged according to the center line of the upper hollow pier. An annular second pouring cavity is left between the concrete wall of the upper hollow pier and the outer wall of the inner sleeve. The second pouring cavity is located above the first pouring cavity and the two are interconnected. The grouting holes and grout outlet holes are both connected to the second pouring cavity.

[0010] Preferably, the outer wall of the inner sleeve is provided with a plurality of second shear keys along the circumferential direction at a position corresponding to the second casting cavity, and the second shear keys extend into the second casting cavity.

[0011] Preferably, the lower end of the upper hollow pier is provided with a plurality of reinforcing ribs spaced apart along the circumference. The upper end of the reinforcing ribs is embedded in the concrete wall of the upper hollow pier, and the lower end extends through the second casting cavity and into the first casting cavity.

[0012] Preferably, the upper section of the inner sleeve is embedded in the inner side of the lower end of the concrete wall of the upper hollow pier through a first shear key, and the lower end of the concrete wall of the upper hollow pier has an annular semi-open groove on the side near the inner sleeve. The semi-open groove cooperates with the outer wall of the inner sleeve to form a second casting cavity.

[0013] Preferably, the lower section of the outer sleeve is embedded in the outer side of the upper end of the concrete wall of the lower hollow pier column via a third shear key;

[0014] The outer diameter and inner cavity diameter of the upper hollow pier and the lower hollow pier are equal. The outer diameter of the lower hollow pier is equal to the outer diameter or inner diameter of the outer sleeve. The inner cavity diameter of the upper hollow pier is equal to the inner diameter or outer diameter of the inner sleeve.

[0015] Preferably, the end diaphragm is provided with a limiting boss, and the lower end of the inner sleeve is sleeved on the limiting boss, forming a third casting cavity between the limiting boss and the inner diaphragm.

[0016] Preferably, the inner sleeve has multiple stiffening ribs staggered on the side of the inner diaphragm away from the lower hollow pier, and each stiffening rib connects the inner wall of the inner sleeve and the inner diaphragm.

[0017] Preferably, the distance between the lower surface of the inner diaphragm and the lower end of the inner sleeve is less than or equal to half the height of the inner sleeve.

[0018] The present invention also provides a construction method for the connection structure between the precast hollow piers of the bridge, comprising:

[0019] S1. The upper hollow pier and the lower hollow pier are prefabricated in the factory, with an inner sleeve embedded at the lower end of the upper hollow pier and an outer sleeve embedded at the upper end of the lower hollow pier.

[0020] S2. After the installation of the lower hollow pier is completed at the construction site, the upper hollow pier is hoisted above the lower hollow pier and the two are connected; wherein, the lower end of the inner sleeve is fitted onto the limiting protrusion on the lower hollow pier, and the upper hollow pier and the lower hollow pier are coaxial.

[0021] S3. Inject ultra-high performance concrete into the grouting hole. When the ultra-high performance concrete overflows from the grout outlet hole, it indicates that the first pouring cavity, the second pouring cavity, and the third pouring cavity have been filled with ultra-high performance concrete. End the grouting and seal the grouting hole and the grout outlet hole.

[0022] S4. After the ultra-high performance concrete has cured for time T, return to step S2 to install the next section of the hollow pier column, and so on until the construction of the entire pier column is completed.

[0023] The application of the technical solution of the present invention has the following beneficial effects:

[0024] The connection structure of this invention requires no formwork during construction, significantly reducing construction time, equipment, and labor costs. It eliminates the need for high-altitude operations such as formwork erection, binding, and dismantling, making construction quick, simple, and highly safe. Each component of the structure plays a vital role throughout the entire construction-operation phase, specifically:

[0025] a) During construction, the outer sleeve serves as the outer formwork for casting. In its operational phase, it connects the upper and lower structures vertically and provides a superior confinement function compared to stirrups horizontally. This ensures that the connection nodes do not require stirrups but still have a stronger confinement function than other parts. It eliminates the need to tie stirrups during prefabrication or before grouting, making the prefabrication or construction of the structure simpler. At the same time, it conforms to the current mainstream seismic design principle of strong node design (i.e., the strength of the connection node is much higher than the strength of other segments).

[0026] (b) During construction, the inner sleeve serves as the inner formwork for casting and the limiting structure during docking. During operation, it plays a connecting role between the upper and lower structures in the vertical direction and a reinforcing role for the inner wall of the connection node in the horizontal direction. The inner and outer steel walls of the outer sleeve and inner sleeve give the connection node a structure similar to that of steel pipe concrete. Therefore, the cast-in-place part of the node has a stronger compressive strength than the precast part, realizing the current mainstream strong node design in seismic design (i.e., the strength of the connection node is much higher than the strength of other segments). Under seismic action, the connection node will not fail preferentially.

[0027] c) The internal and end diaphragms can provide lateral reinforcement to the hollow pier segments, ensuring the stability and strength of the prefabricated hollow pier segments during transportation. During construction, the internal and end diaphragms act as templates, preventing grout from entering the cavity of the hollow pier segment and being squeezed against the wall during grouting. In the operation phase, the internal and end diaphragms, together with the concrete in the third pouring cavity, serve as the final pier diaphragm to participate in the pier's stress formation, further reinforcing the connection nodes. This makes the structure more in line with the mainstream structural design concept of strong nodes, achieving multiple uses for one plate and further demonstrating the high material utilization rate.

[0028] Each component of the connection structure of this invention reinforces the connection node, ensuring that the connection node will not be damaged preferentially under earthquake action. The earthquake damage area is outside the connection node of the pier column, making post-earthquake repair relatively easy. At the same time, the connection structure of this invention uses a strong node design concept, and other parts are prefabricated in the factory. Therefore, after construction, the entire pier column can achieve the same connection effect as cast-in-place and has a certain degree of toughness and earthquake resistance.

[0029] The connection structure and construction method of the present invention are particularly suitable for the prefabrication and assembly construction of large-size piers. The assembly process is very simple, and the size of the prefabricated piers can be significantly increased. The piers are assembled in segments, which reduces the difficulty of applying prefabricated piers and makes the application scenarios more extensive.

[0030] This invention creates a cavity to accommodate cracks in ultra-high performance concrete by setting a second pouring cavity on the inner side above the first pouring cavity. The original concrete wall of the upper hollow pier can serve as a sufficiently thick concrete protective layer to prevent the steel reinforcement from affecting the structural bearing capacity due to corrosion. This ensures both the mechanical performance of the structure and the aesthetics of the entire pier. At the same time, by embedding a second shear key and reinforcing bars in the second pouring cavity to strengthen the structure, the effects of cracking of the ultra-high performance concrete in the second pouring cavity and the shortness of the second shear key can be offset, eliminating the weak points in the connection structure.

[0031] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0032] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0033] Figure 1 This is a schematic diagram of the structure before the connection structure between the precast hollow bridge piers of the present invention is connected;

[0034] Figure 2 This is a cross-sectional view of the connection structure between the prefabricated hollow piers of the bridge according to the present invention after docking;

[0035] Figure 3 yes Figure 2 Sectional view at point AA;

[0036] Figure 4 This is a partial sectional view of the connection structure between the prefabricated hollow piers of the bridge according to the present invention after docking.

[0037] Figure 5 yes Figure 1 Schematic diagram of the inner sleeve;

[0038] Among them, 1. Upper hollow pier column, 1.1. Upper main reinforcement, 1.2. Semi-open groove, 2. Grouting hole, 3. Inner sleeve, 3.1. Grouting groove, 3.2. First shear key, 3.3. Second shear key, 3.4. Stiffening rib, 3.5. Inner tube diaphragm, 4. Reinforcing rib, 5. Lower hollow pier column, 5.1. Lower main reinforcement, 5.2. End diaphragm, 5.3. Limiting boss, 6. Outer sleeve, 6.1. Third shear key, 7. First casting cavity, 8. Second casting cavity, 9. Third casting cavity, 10. Grouting hole. Detailed Implementation

[0039] To facilitate understanding of the present invention, a more complete description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0041] Example:

[0042] See Figures 1-5 This embodiment provides a connection structure between prefabricated hollow bridge piers, including an upper hollow pier 1, an inner sleeve 3, a lower hollow pier 5, and an outer sleeve 6;

[0043] The inner sleeve 3 is provided with a first shear key 3.2. The inner sleeve 3 is embedded in the lower end of the upper hollow pier 1 through the first shear key 3.2 in its upper section. The inner sleeve 3 is provided with an inner tube transverse partition 3.5. The inner sleeve 3 has a plurality of grout inlets 3.1 spaced circumferentially on the side wall below the inner tube transverse partition 3.5. The outer sleeve 6 is provided with a third shear key 6.1. The outer sleeve 6 is embedded in the upper end of the lower hollow pier 5 through the third shear key 6.1 in its lower section. The upper end of the lower hollow pier 5 is provided with an end transverse partition 5.2.

[0044] After the upper hollow pier 1 and the lower hollow pier 5 are connected, the lower section of the inner sleeve 3 is inserted into the upper section of the outer sleeve 6, forming an annular first casting cavity 7 between them. The first shear key 3.2 of the lower section of the inner sleeve 3 and the third shear key 6.1 of the upper section of the outer sleeve 6 are both located in the first casting cavity 7. The upper main reinforcement 1.1 in the upper hollow pier 1 and the lower main reinforcement 5.1 in the lower hollow pier 5 both extend into the first casting cavity 7, and the upper main reinforcement 1.1 and the lower main reinforcement 5.1 are overlapped. The inner transverse partition 3.5 is located above the end transverse partition 5.2, forming a third casting cavity 9 between them. The grout inlet 3.1 connects the first casting cavity 7 and the third casting cavity 9.

[0045] In this embodiment, the inner sleeve 3 and the outer sleeve 6 cooperate to form a first casting cavity 7. The first casting cavity 7 is embedded with an upper main reinforcement 1.1, a lower main reinforcement 5.1, a first shear key 3.2, and a third shear key 6.1. At the same time, the inner sleeve 3 and the outer sleeve 6 can replace the stirrups and provide a stronger clamping effect than the stirrups, which can effectively ensure the strength requirements of the connection structure. Meanwhile, the inner diaphragm 3.5 and the end diaphragm 5.2 cooperate to form a third casting cavity 9. After the third casting cavity is filled with concrete, the inner diaphragm 3.5, the end diaphragm 5.2, and the concrete in the third casting cavity 9 form the diaphragm of the connection structure, which has the function of lateral reinforcement of the connection structure and provides lateral shear resistance during the operation of the pier column.

[0046] like Figure 1 , Figure 3 and Figure 5 As shown, in this embodiment, the outer side wall of the inner sleeve 3 is provided with a plurality of first shear keys 3.2 at intervals, and the inner side wall of the outer sleeve 6 is provided with a plurality of third shear keys 6.1 at intervals. The first shear keys 3.2 and the third shear keys 6.1 are closely arranged in the vertical direction, but relatively sparsely arranged in the horizontal direction. Furthermore, after the upper hollow pier 1 and the lower hollow pier 5 are connected, the first shear keys 3.2 and the third shear keys 6.1 are offset in the circumferential direction.

[0047] Preferably, at least one-third (preferably one-half) of the inner sleeve 3 is anchored to the upper hollow pier 1 in the height direction, and at least one-third (preferably one-half) of the outer sleeve 6 is anchored to the lower hollow pier 5 in the height direction to ensure the anchorage strength of the inner sleeve 3 and the outer sleeve 6; at the same time, the lap length between the upper main reinforcement 1.1 and the lower main reinforcement 5.1 is greater than or equal to 5d, preferably greater than or equal to 6d, where d represents the diameter of the upper main reinforcement 1.1 or the lower main reinforcement 5.1.

[0048] Those skilled in the art will understand that the upper hollow pier 1 and lower hollow pier 5 in this embodiment are merely for distinguishing the vertical position of each hollow pier segment. For a single hollow pier segment, this is equivalent to pre-embedding an inner sleeve 3 at its lower end, simultaneously casting an end diaphragm 5.2 and a limiting boss 5.3 at its upper end, and pre-embedding an outer sleeve 6 at the upper end of the hollow pier segment. For a single hollow pier segment, both ends are respectively provided with end diaphragms 5.2 and an inner sleeve 3 containing an inner diaphragm 3.5 for lateral structural reinforcement, which can ensure the stability and strength of each prefabricated hollow pier segment during transportation and prevent damage to the hollow pier segment during transportation.

[0049] Furthermore, the upper hollow pier 1 is provided with grouting holes 2 and grout outlet holes 10. Both grouting holes 2 and grout outlet holes 10 are inclined and symmetrically arranged according to the centerline of the upper hollow pier 1. Concrete is poured into the first pouring cavity 7 and the third pouring cavity 9 through the grouting holes 2. When concrete overflows from the grout outlet holes 10, it indicates that the concrete filling is complete. In this embodiment, the inclined arrangement of grouting holes 2 and grout outlet holes 10 means that the inlet of the grouting hole 2 is higher than its outlet, and the inlet of the grout outlet hole 10 is lower than its outlet. In this embodiment, the symmetrical arrangement of the grouting holes 2 and grout outlet holes 10 according to the centerline of the upper hollow pier 1 and their inclined arrangement effectively ensure the compactness of the grouting.

[0050] Furthermore, in this embodiment, ultra-high performance concrete (UHPC) is poured into the first pouring cavity 7 and the third pouring cavity 9. Because the cement content of ultra-high performance concrete (UHVPC) (approximately 28%) is about three times that of ordinary concrete (Normal Concrete, abbreviated as NC) (approximately 9%), the shrinkage of UHVPC due to cement hydration is much greater than that of ordinary concrete. To avoid the problem of obvious cracks caused by shrinkage at the top of the first pouring cavity 7, which would lead to the gradual corrosion of the reinforcing steel at the cracks due to the loss of the concrete protective layer and affect the structural bearing capacity, this embodiment further provides an annular second pouring cavity 8 between the concrete wall of the upper hollow pier 1 and the outer wall of the inner sleeve 3. The second pouring cavity 8 is located above the first pouring cavity 7 and the two are interconnected. The grouting hole 2 and the grout outlet hole 10 are both connected to the second pouring cavity 8. In this way, all the cracks generated by the UHVPC can be placed in the second pouring cavity 8. Since the outer side of the second pouring cavity 8 is also covered by the concrete wall of the upper hollow pier 1, the problem of the reinforcing steel in the second pouring cavity 8 losing the concrete protective layer and corroding can be effectively prevented.

[0051] Specifically, the upper section of the inner sleeve 3 is embedded in the inner side of the lower end of the concrete wall of the upper hollow pier 1 via the first shear key 3.2. The lower end of the concrete wall of the upper hollow pier 1 has an annular semi-open groove 1.2 on the side near the inner sleeve 3. The semi-open groove 1.2 cooperates with the outer wall of the inner sleeve 3 to form a second pouring cavity 8. In this way, the second pouring cavity 8 can be set on the inner side of the connecting structure. The original concrete wall of the upper hollow pier 1 can serve as a concrete protective layer of sufficient thickness to prevent the steel reinforcement from affecting the structural bearing capacity due to corrosion. This ensures both the mechanical performance of the structure and the aesthetics of the entire pier.

[0052] like Figures 2-4As shown, to ensure the mechanical properties at the second casting cavity 8, in this embodiment, the outer wall of the inner sleeve 3 is provided with multiple second shear keys 3.3 along the circumferential direction at the position corresponding to the second casting cavity 8. The second shear keys 3.3 extend into the second casting cavity 8. Similarly, the second shear keys 3.3 are densely arranged vertically and relatively sparsely arranged horizontally. Furthermore, the lower end of the upper hollow pier 1 is provided with multiple reinforcing ribs 4 at intervals along the circumferential direction. The upper end of the reinforcing ribs 4 is embedded in the concrete wall of the upper hollow pier 1, and its lower end passes through the second casting cavity 8 and extends into the first casting cavity 7.

[0053] In this embodiment, a second pouring cavity 8 is provided on the inner side above the first pouring cavity 7 to form a cavity that can accommodate cracks in ultra-high performance concrete. At the same time, the structure is strengthened by embedding a second shear key 3.3 and a reinforcing bar 4 in the second pouring cavity 8. This can offset the effects of cracking of ultra-high performance concrete in the second pouring cavity 8 and the shortness of the second shear key 3.3, and eliminate the weak surface of the connection structure.

[0054] like Figures 1-2 As shown, the lower section of the outer sleeve 6 is embedded in the outer side of the upper end of the concrete wall of the lower hollow pier 5 via a third shear key 6.1; furthermore, the outer diameter and inner cavity diameter of the upper hollow pier 1 and the lower hollow pier 5 are equal, the outer diameter of the lower hollow pier 5 is equal to the outer diameter or inner diameter of the outer sleeve 6 (i.e., the outer surface of the lower hollow pier 5 is flush with the outer side wall or inner side wall of the outer sleeve 6), and the inner cavity diameter of the upper hollow pier 1 is equal to the inner diameter or outer diameter of the inner sleeve 3 (i.e., the inner cavity side wall of the upper hollow pier 1 is flush with the inner side wall or outer side wall of the inner sleeve 3). Since the outer sleeve 6 and the inner sleeve 3 have relatively thin walls, the outer diameter of the lower hollow pier 5 is equal to the outer diameter or inner diameter of the outer sleeve 6, and the inner diameter of the upper hollow pier 1 is equal to the inner diameter or outer diameter of the inner sleeve 3. This satisfies the requirement that the concrete wall thickness of the hollow pier should not change abruptly, effectively avoids the adverse effects of stress concentration, and ensures the mechanical rationality of the connection structure.

[0055] like Figure 2 As shown, the end diaphragm 5.2 is provided with a limiting boss 5.3, and the lower end of the inner sleeve 3 is fitted onto the limiting boss 5.3. The limiting boss 5.3 and the inner diaphragm 3.5 form a third casting cavity 9. Specifically, the upper end of the limiting boss 5.3 is chamfered, the shape of the limiting boss 5.3 is consistent with the shape of the lower end of the inner sleeve 3, and the circumferential dimension of the limiting boss 5.3 is slightly smaller than the circumferential dimension of the inner side of the lower end of the inner sleeve 3. When hoisting the upper hollow pier 1 and the lower hollow pier 5 for docking, the limiting boss 5.3 can assist in the rapid positioning between the upper hollow pier 1 and the lower hollow pier 5. At the same time, the limiting boss 5.3 can provide a certain lateral shear resistance during the operation of the pier.

[0056] like Figure 2 , Figure 3 and Figure 5 As shown, the inner sleeve 3 has multiple stiffening ribs 3.4 staggered on the side of the inner diaphragm 3.5 away from the lower hollow pier column 5. Each stiffening rib 3.4 connects the inner wall of the inner sleeve 3 and the inner diaphragm 3.5. In this embodiment, by providing stiffening ribs 3.4 on the inner sleeve 3, the thickness of the diaphragm of the connecting structure (i.e., the thickness of the pier column transverse structure formed by the end diaphragm 5.2, the limiting boss 5.3, the concrete in the third pouring cavity 9, and the inner diaphragm 3.5) can be effectively limited, reducing the adverse effects of excessively thick diaphragms on the structure and seismic performance.

[0057] Specifically, the inner sleeve 3 is provided with multiple stiffening ribs 3.4 spaced apart along a first direction and a second direction. Each stiffening rib 3.4 has a clearance groove at its intersection with another stiffening rib 3.4 to achieve an alternating arrangement of two stiffening ribs 3.4. Alternatively, in some embodiments, multiple long stiffening ribs 3.4 may be spaced apart along the first direction, and then multiple short stiffening ribs 3.4 may be spaced apart along the second direction between adjacent long stiffening ribs 3.4 and between the long stiffening ribs 3.4 and the inner wall of the inner sleeve 3. The first and second directions are perpendicular to each other.

[0058] like Figure 2 As shown, the distance between the lower surface of the inner transverse partition 3.5 and the lower end of the inner sleeve 3 is less than or equal to half the height of the inner sleeve 3, and more preferably less than or equal to one-third of the height of the inner sleeve 3. Specifically, the distance between the inner transverse partition 3.5 and the lower end of the inner sleeve 3 can be set according to the actual situation. Since a stiffening rib 3.4 is added in this embodiment, the distance between the inner transverse partition 3.5 and the lower end of the inner sleeve 3 can be set smaller (i.e., the height of the third casting cavity 9 can be set smaller), effectively reducing the thickness of the connecting structure partition.

[0059] Furthermore, the upper end of the grout inlet 3.1 should be flush with the lower surface of the inner diaphragm 3.5 to ensure that the ultra-high performance concrete can fully fill the third pouring cavity 9 and improve the compactness of the concrete filling.

[0060] Preferably, the thickness of the inner transverse partition 3.5 and the stiffening rib 3.4 can be set to be the same as the wall thickness of the inner sleeve 3, or it can be thickened or thinned according to the actual situation; the inner sleeve 3, the inner transverse partition 3.5, the stiffening rib 3.4, the outer sleeve 6, the first shear key 3.2, the second shear key 3.3 and the third shear key 6.1 are all made of steel.

[0061] Preferably, the first shear key 3.2, the second shear key 3.3, and the third shear key 6.1 can be protruding structures such as shear studs, corrugated plates, or serrated plates, and can be set according to the actual engineering needs.

[0062] Preferably, the connection structure in this embodiment can be applied to the connection between upper and lower hollow pier segments in a circular hollow pier, and also to the connection between upper and lower hollow pier segments in a square hollow pier. Furthermore, the connection structure in this embodiment can also be applied to the connection between upper and lower hollow pier segments in a hollow pier with a variable cross-section, where the bottom cross-section of the pier is larger than the top cross-section, and the concrete wall thickness of each hollow pier segment is consistent.

[0063] The connection structure in this embodiment requires no formwork, significantly reducing construction time, equipment, and labor costs. It eliminates the need for high-altitude operations such as formwork erection, binding, and dismantling, making construction quick, simple, and highly safe. All structural components function effectively throughout the construction-operation phase, specifically:

[0064] a) The outer sleeve 6 serves as the outer formwork for casting during construction. During its operation, it connects the upper and lower structures vertically and has a better ferrule function than stirrups horizontally. It can ensure that the connection node does not need to be equipped with stirrups but still has a stronger ferrule function than other parts. It eliminates the process of tying stirrups during prefabrication or before grouting, making the prefabrication or construction of the structure simpler. At the same time, it conforms to the current mainstream seismic design of strong node design (i.e., the strength of the connection node is much higher than the strength of other segments).

[0065] (b) During construction, the inner sleeve 3 serves as the inner formwork for casting and the limiting structure during docking. During operation, it plays a connecting role between the upper and lower structures in the vertical direction and a reinforcing role for the inner wall of the connection node in the horizontal direction. The inner and outer steel walls of the outer sleeve 6 and the inner sleeve 3 give the connection node a structure similar to that of steel pipe concrete. Therefore, the cast-in-place part of the node has a stronger compressive strength than the precast part, realizing the current mainstream strong node design in seismic design (i.e., the strength of the connection node is much higher than the strength of other segments). Under seismic action, the connection node will not fail preferentially.

[0066] c) The internal and end diaphragms can provide lateral reinforcement to the hollow pier segments, ensuring the stability and strength of the prefabricated hollow pier segments during transportation. During construction, the internal and end diaphragms act as templates, preventing grout from entering the cavity of the hollow pier segment and being squeezed against the wall during grouting. In the operation phase, the internal and end diaphragms, together with the concrete in the third pouring cavity, serve as the final pier diaphragm to participate in the pier's stress formation, further reinforcing the connection nodes. This makes the structure more in line with the mainstream structural design concept of strong nodes, achieving multiple uses for one plate and further demonstrating the high material utilization rate.

[0067] Furthermore, in this embodiment, each component of the connection structure reinforces the connection node, ensuring that the connection node will not be damaged preferentially under earthquake action. The earthquake damage area is outside the connection node of the pier column, making post-earthquake repair relatively easy. At the same time, this embodiment uses a strong node design concept for the connection structure, and other parts are prefabricated in the factory. Therefore, after construction, the entire pier column can achieve the same connection effect as cast-in-place and has a certain degree of toughness and earthquake resistance.

[0068] This embodiment also provides a construction method for the connection structure between the precast hollow piers of the bridge described above, including:

[0069] S1. The upper hollow pier 1 and the lower hollow pier 5 are prefabricated in the factory, wherein the lower end of the upper hollow pier 1 is embedded with an inner sleeve 3 and the upper end of the lower hollow pier 5 is embedded with an outer sleeve 6.

[0070] Preferably, both the upper hollow pier 1 and the lower hollow pier 5 are prefabricated using ordinary concrete.

[0071] S2. After the installation of the lower hollow pier 5 is completed at the construction site, the upper hollow pier 1 is hoisted above the lower hollow pier 5 and the two are connected; wherein, the lower end of the inner sleeve 3 is sleeved on the limiting boss 5.3 on the lower hollow pier 5, and the upper hollow pier 1 and the lower hollow pier 5 are coaxial.

[0072] Preferably, the connection structure of this embodiment can be used to connect the lowest hollow pier column segment to the pier cap or foundation, or other existing mature technologies can be used for connection.

[0073] S3. Inject ultra-high performance concrete into the grouting hole 2. When the ultra-high performance concrete overflows from the grout outlet hole 10, it indicates that the first pouring cavity 7, the second pouring cavity 8 and the third pouring cavity 9 have been filled with ultra-high performance concrete. End the grouting and seal the grouting hole 2 and the grout outlet hole 10.

[0074] S4. After the ultra-high performance concrete has cured for time T, return to step S2 to install the next section of the hollow pier column 1, and so on until the construction of the entire pier column is completed.

[0075] Preferably, ultra-high performance concrete can produce a compressive strength of not less than 60MPa after two days of curing, at which point the installation of the next section of the hollow pier column 1 can begin, which greatly shortens the construction period compared to the current mainstream climbing formwork construction method for high pier structures.

[0076] The construction method in this embodiment adopts the method of hoisting first and then grouting. There is no time constraint between hoisting and grouting, which is particularly suitable for construction environments where hoisting work is difficult or it is difficult to guarantee hoisting speed or stability. The hoisting speed can be slowed down, and grouting work can be carried out after hoisting is completed and all points are calibrated.

[0077] The connection structure and construction method of this embodiment are particularly suitable for the prefabrication and assembly of large-size piers. The assembly process is very simple, and the size of the prefabricated piers can be significantly increased. The segmented assembly of the piers reduces the difficulty of applying prefabricated piers and broadens their application scenarios. In this embodiment, large-size piers refer to piers whose geometric dimensions (mainly length and cross-section) or weight are too large, resulting in limitations in transportation and hoisting equipment, making it impossible to use integral prefabrication and integral installation.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A connection structure between precast hollow bridge piers, characterized in that, It includes an upper hollow pier (1), an inner sleeve (3), a lower hollow pier (5), and an outer sleeve (6); The inner sleeve (3) is provided with a first shear key (3.2). The inner sleeve (3) is embedded in the lower end of the upper hollow pier (1) through the first shear key (3.2) in its upper section. The inner sleeve (3) is provided with an inner tube transverse partition (3.5). The inner sleeve (3) is provided with multiple grout inlets (3.1) spaced circumferentially on the side wall below the inner tube transverse partition (3.5). The outer sleeve (6) is provided with a third shear key (6.1). The outer sleeve (6) is embedded in the upper end of the lower hollow pier (5) through the third shear key (6.1) in its lower section. The upper end of the lower hollow pier (5) is provided with an end transverse partition (5.2). After the upper hollow pier (1) and the lower hollow pier (5) are connected, the lower section of the inner sleeve (3) is inserted into the upper section of the outer sleeve (6) and a first annular pouring cavity (7) is formed between them. The first shear key (3.2) of the lower section of the inner sleeve (3) and the third shear key (6.1) of the upper section of the outer sleeve (6) are both located in the first pouring cavity (7). The upper main reinforcement (1.1) in the upper hollow pier (1) and the lower main reinforcement (5.1) in the lower hollow pier (5) both extend into the first pouring cavity (7) and the upper main reinforcement (1.1) and the lower main reinforcement (5.1) are overlapped. The inner diaphragm (3.5) is located above the end diaphragm (5.2) and a third pouring cavity (9) is formed between them. The grout inlet (3.1) connects the first pouring cavity (7) and the third pouring cavity (9). The upper hollow pier (1) is provided with grouting holes (2) and grout outlet holes (10). The grouting holes (2) and grout outlet holes (10) are both inclined and symmetrically arranged according to the center line of the upper hollow pier (1). An annular second pouring cavity (8) is left between the concrete wall of the upper hollow pier (1) and the outer wall of the inner sleeve (3). The second pouring cavity (8) is located above the first pouring cavity (7) and the two are interconnected. The grouting holes (2) and grout outlet holes (10) are both connected to the second pouring cavity (8).

2. The connection structure between precast hollow bridge piers according to claim 1, characterized in that, The outer wall of the inner sleeve (3) is provided with a plurality of second shear keys (3.3) in the circumferential direction at the position corresponding to the second casting cavity (8), and the second shear keys (3.3) extend into the second casting cavity (8).

3. The connection structure between precast hollow bridge piers according to claim 2, characterized in that, The lower end of the upper hollow pier (1) is provided with a plurality of reinforcing ribs (4) spaced apart along the circumference. The upper end of the reinforcing ribs (4) is embedded in the concrete wall of the upper hollow pier (1), and the lower end extends through the second pouring cavity (8) and into the first pouring cavity (7).

4. The connection structure between precast hollow bridge piers according to claim 3, characterized in that, The upper section of the inner sleeve (3) is embedded in the inner side of the lower end of the concrete wall of the upper hollow pier (1) through the first shear key (3.2). The lower end of the concrete wall of the upper hollow pier (1) is provided with an annular semi-open groove (1.2) on the side near the inner sleeve (3). The semi-open groove (1.2) cooperates with the outer side wall of the inner sleeve (3) to form a second casting cavity (8).

5. The connection structure between precast hollow bridge piers according to claim 4, characterized in that, The lower section of the outer sleeve (6) is embedded in the outer side of the upper end of the concrete wall of the lower hollow pier column (5) through the third shear key (6.1); The outer diameter and inner cavity diameter of the upper hollow pier (1) and the lower hollow pier (5) are equal. The outer diameter of the lower hollow pier (5) is equal to the outer diameter or inner diameter of the outer sleeve (6). The inner cavity diameter of the upper hollow pier (1) is equal to the inner diameter or outer diameter of the inner sleeve (3).

6. The connection structure between precast hollow bridge piers according to claim 1, characterized in that, The end diaphragm (5.2) is provided with a limiting boss (5.3), and the lower end of the inner sleeve (3) is sleeved on the limiting boss (5.3). The limiting boss (5.3) and the inner diaphragm (3.5) form a third casting cavity (9).

7. The connection structure between precast hollow bridge piers according to claim 1, characterized in that, The inner sleeve (3) has multiple stiffening ribs (3.4) staggered on the side of the inner diaphragm (3.5) away from the lower hollow pier (5). Each stiffening rib (3.4) is connected to the inner wall of the inner sleeve (3) and the inner diaphragm (3.5).

8. The connection structure between precast hollow bridge piers according to claim 1, characterized in that, The distance between the lower surface of the inner diaphragm (3.5) and the lower end of the inner sleeve (3) is less than or equal to half the height of the inner sleeve (3).

9. A construction method for the connection structure between precast hollow bridge piers as described in any one of claims 1-8, characterized in that, include: S1. The upper hollow pier (1) and the lower hollow pier (5) are prefabricated in the factory. The lower end of the upper hollow pier (1) is embedded with an inner sleeve (3) and the upper end of the lower hollow pier (5) is embedded with an outer sleeve (6). S2. After the installation of the lower hollow pier (5) is completed at the construction site, the upper hollow pier (1) is hoisted above the lower hollow pier (5) and the two are connected; wherein, the lower end of the inner sleeve (3) is fitted onto the limiting boss (5.3) on the lower hollow pier (5), and the upper hollow pier (1) and the lower hollow pier (5) are coaxial. S3. Inject ultra-high performance concrete from the grouting hole (2). When the ultra-high performance concrete overflows from the grout outlet hole (10), it indicates that the first pouring cavity (7), the second pouring cavity (8), and the third pouring cavity (9) have been filled with ultra-high performance concrete. End the grouting and seal the grouting hole (2) and the grout outlet hole (10). S4. After the ultra-high performance concrete has cured for time T, return to step S2 to install the next section of the hollow pier (1), and so on until the construction of the entire pier is completed.

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