A prefabricated concrete bridge pier with external UHPC steel pipe connection and its construction method

Abstract

This invention belongs to the field of bridge engineering technology, and particularly relates to a prefabricated concrete bridge pier using external UHPC steel pipe connections and its construction method. By setting bottom segment units, external UHPC steel pipe units, and anchor units on the slotted abutment unit, this invention enhances the strength of the connection structure between the segments and the abutment in the prefabricated concrete bridge pier, further disperses the stress, and strengthens the overall impact resistance of the pier. Furthermore, this invention provides a construction method for the aforementioned prefabricated concrete bridge pier, ensuring its efficient construction.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering technology, and in particular relates to a prefabricated concrete bridge pier with external UHPC steel pipe connection and its construction method. Background Technology

[0002] Precast concrete bridge piers are characterized by the fact that at least all pier segments are prefabricated in a factory. Therefore, on-site construction typically only requires: 1. Connecting the abutment and the bottom pier segment; 2. Connecting the remaining pier segments sequentially. Currently, the connection technology between pier segments is relatively mature in the precast concrete bridge pier industry. In other words, the strength of the connection structure between the abutment and the bottom pier segment is crucial to the quality of the precast concrete bridge pier.

[0003] The most common method for assembling the bottom pier segments and the abutment is the slot-type connection. The general steps of this method are as follows:

[0004] First, an anchor plate is specially installed on the lower end face of the bottom pier segment, and an installation groove is reserved on the bearing platform to expose the anchor rod;

[0005] Secondly, the bottom pier segment is inserted into the installation groove, and the anchor rod is inserted into the anchor plate and tightened.

[0006] Finally, the installation slot is filled with concrete, and the entire assembly and connection process is completed.

[0007] Chinese utility model patent with patent publication number CN206941372U and publication date of January 30, 2018, discloses a dumbbell-shaped steel-concrete composite bridge pier and its connection structure with the abutment. The dumbbell-shaped steel pipe consists of two circular steel pipes and a double-layer steel plate welded between the two circular steel pipes. The bottom of the dumbbell-shaped steel pipe is welded with an end plate and the inside is filled with concrete. The bridge pier and the abutment are connected by a grouted corrugated sleeve embedded connection.

[0008] The pier-abutment connection structure in this utility model patent uses the anchoring function of the end plate and the circumferential support function of the grouting corrugated sleeve to ensure basic connection strength.

[0009] However, the biggest drawback of this connection structure, which is the technical problem that this invention aims to solve, is that the connection parts of the bridge pier are all located at the lower end, resulting in excessive force concentration. Therefore, the connection strength and structural integrity are not high, and the connection parts are prone to breakage and disintegration when the bridge pier is subjected to a large lateral impact.

[0010] Therefore, in summary, there is an urgent need for a high-strength prefabricated concrete bridge pier with a relatively dispersed stress area, greater connection strength, and less susceptibility to breakage in the installation structure between the bottom pier and the abutment. Summary of the Invention

[0011] This invention provides a prefabricated concrete bridge pier with external UHPC steel pipe connection. By setting bottom segment units, external UHPC steel pipe units, and anchor units on the slotted pier unit, the connection structure between the segments and the pier cap in the prefabricated concrete bridge pier has greater strength, the stress distribution is more dispersed, and the overall impact resistance of the bridge pier is stronger.

[0012] Furthermore, this invention also provides a construction method for the aforementioned prefabricated concrete bridge pier, comprising the following steps in sequence: S1, obtaining an outer UHPC steel pipe unit; S2, arranging a reinforcing cage and pouring concrete within the outer UHPC steel pipe unit, solidifying to form a bottom segment unit, thus obtaining a complete bridge pier segment; S3, obtaining a slotted pier cap unit by arranging a reinforcing cage and pouring concrete; S4, first lifting the bridge pier segment, then inserting the bridge pier segment onto the slotted pier cap unit to obtain the bridge pier body; S5, finally tightening and pouring anchor units onto the bridge pier body, thus completing the construction method for a single bridge pier segment style prefabricated concrete bridge pier, ultimately ensuring that the prefabricated concrete bridge pier can be efficiently constructed.

[0013] The technical solution adopted by the present invention to solve the above problems is: a prefabricated concrete bridge pier with external UHPC steel pipe connection, the structure including a slotted pier unit, a bottom segment unit inserted into the slotted pier unit, an external UHPC steel pipe unit sleeved on the bottom segment unit and inserted into the slotted pier unit, and an anchor unit set on the slotted pier unit for installing the external UHPC steel pipe unit.

[0014] A further preferred technical solution is that: the slotted foundation unit includes a foundation body, a high-level groove of the anchor unit is disposed on the upper surface of the foundation body and used to set the high-level groove of the anchor unit, a low-level groove of the bottom segment unit is disposed on the bottom surface of the high-level groove and used to insert the low-level groove of the bottom segment unit, and an anchor rod of the outer UHPC steel pipe unit is disposed on the foundation body and exposed at the upper end in the high-level groove and used to insert the anchor rod of the outer UHPC steel pipe unit.

[0015] A further preferred technical solution is that the bottom segment unit includes a segment body whose lower end is inserted into the low-position groove, and segment reinforcement bars disposed on the segment body and exposed at the upper end, which are used to connect to the upper pier segment.

[0016] A further preferred technical solution is that the outer UHPC steel pipe unit includes a steel pipe sleeved on the main body of the segment, an open ring disposed on the outer ring surface of the steel pipe for inserting into the anchor rod, and an annular UHPC layer disposed on the outer ring surface of the steel pipe and the upper surface of the open ring.

[0017] A further preferred technical solution is that the outer UHPC steel pipe unit also includes shear keys disposed on the inner and outer annular surfaces of the steel pipe, which are used to reinforce the connection between the segment body and the annular UHPC layer.

[0018] A further preferred technical solution is that the outer UHPC steel pipe unit also includes circumferential reinforcing bars disposed within the annular UHPC layer.

[0019] A further preferred technical solution is that the anchor unit includes an anchor nut disposed on the anchor rod, and an anti-rust layer disposed in the high-position groove for covering the anchor rod and the anchor nut.

[0020] A further preferred technical solution is that: the slotted foundation unit further includes foundation reinforcement bars disposed on the foundation body and exposed on the bottom surface of the low-level slot; the bottom segment unit further includes an inward recessed area disposed within the outer UHPC steel pipe unit and located below the segment body, used to accommodate the foundation reinforcement bars, and a vertical channel disposed on the segment body, used to add concrete to the inward recessed area when connecting and casting the segment reinforcement bars.

[0021] A further preferred technical solution is that the bottom segment unit further includes a second circumferential reinforcing bar disposed within the segment body and used to connect the segment reinforcing bars, and the vertical channel is disposed between two radially adjacent circles of the second circumferential reinforcing bars.

[0022] A construction method for prefabricated concrete bridge piers using externally encased UHPC steel pipe connections includes the following steps:

[0023] S1. The outer UHPC steel pipe unit is manufactured by welding steel materials;

[0024] S2. Inside the outer UHPC steel pipe unit, a reinforcing cage is arranged, concrete is poured, and the bottom segment unit is solidified to obtain a complete pier segment.

[0025] S3. The slotted foundation unit is obtained by arranging steel cages and pouring concrete.

[0026] S4. First, lift the pier segment, then insert the pier segment into the slotted pier unit to obtain the pier body;

[0027] S5. Finally, the anchor unit is tightened and poured on the main body of the pier to form the anchor unit, thus completing the construction method of the prefabricated concrete pier of the single pier segment. Attached Figure Description

[0028] Figure 1This is a schematic diagram of the prefabricated concrete bridge pier in this invention.

[0029] Figure 2 This is a schematic diagram of the slotted foundation unit in this invention.

[0030] Figure 3 This is a schematic diagram of the location and structure of the outer UHPC steel pipe unit in this invention.

[0031] Figure 4 This is a schematic diagram of the position and structure of the segmental reinforcing bars in this invention.

[0032] Figure 5 This is a schematic diagram of the position and structure of the anchor unit in this invention.

[0033] Figure 6 This is a schematic diagram showing the location of the reinforcing steel bars and the recessed area in the foundation of this invention.

[0034] Figure 7 This is a schematic diagram showing the positions of the anchor rods and foundation reinforcement bars in this invention from a top-down perspective.

[0035] Figure 8 This is a schematic diagram of the position and structure of the vertical channel in this invention.

[0036] The meanings of the labels in the attached diagram are as follows.

[0037] Slotted foundation unit 1, bottom segment unit 2, outer UHPC steel pipe unit 3, anchor unit 4;

[0038] The following components are included: foundation body 101, high-level groove 102, low-level groove 103, anchor rod 104, segment body 201, segment reinforcement 202, steel pipe 301, perforated ring 302, annular UHPC layer 303, shear key 304, circumferential reinforcement 305, anchor nut 401, anti-rust layer 402, foundation reinforcement 105, inner recess 203, vertical duct 204, and second circumferential reinforcement 205. Detailed Implementation

[0039] The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

[0040] As attached Figure 1-8 As shown, a prefabricated concrete bridge pier using an external UHPC steel pipe connection includes a slotted pier unit 1, a bottom segment unit 2 inserted into the slotted pier unit 1, an external UHPC steel pipe unit 3 sleeved on the bottom segment unit 2 and inserted into the slotted pier unit 1, and an anchor unit 4 disposed on the slotted pier unit 1 for installing the external UHPC steel pipe unit 3.

[0041] In this embodiment, to improve the structural strength of the prefabricated concrete bridge pier, three aspects can be addressed: first, improving the strength of the pier cap itself; second, improving the strength of the segments themselves; and third, improving the strength of the connection structure between the pier cap and the segments.

[0042] The slotted foundation unit 1 includes an internal steel mesh cage structure with sufficient strength. The bottom segment unit 2 not only has an internal steel mesh cage but also an external UHPC steel pipe unit 3, which further enhances its strength. The most important third point is that the bottom segment unit 2 is first inserted into the slotted foundation unit 1, and then the external UHPC steel pipe unit 3 is used for the connection and stress of the middle and a large area.

[0043] The final result is that, when the bottom segment unit 2 is subjected to lateral impact, it is less likely to tilt, break, or disintegrate compared to the existing pier segments that are only bolted at the lower end.

[0044] Therefore, the outer UHPC steel pipe unit 3 is crucial, as it can both reinforce the bottom segment unit 2 itself and optimize the connection structure between the segment and the foundation.

[0045] The slotted foundation unit 1 includes a foundation body 101, a high slot 102 for setting the anchor unit 4 on the upper surface of the foundation body 101, a low slot 103 for inserting the bottom segment unit 2 on the bottom surface of the high slot 102, and an anchor rod 104 for inserting the outer UHPC steel pipe unit 3 on the foundation body 101 and exposed at the upper end of the high slot 102.

[0046] In this embodiment, the anchor rod 104 is part of the longitudinal reinforcing bar of the foundation steel mesh cage, and it is threaded. On the other hand, the foundation steel mesh cage is appropriately separated at the high-level groove 102 and the low-level groove 103, or round steel bars are used to ensure that space is left for the groove opening.

[0047] The high-level groove 102 and the low-level groove 103 are both circular grooves with their centers vertically aligned. There are 5-10 anchor rods 104, which are evenly arranged in a circle on the high-level groove 102.

[0048] The bottom segment unit 2 includes a segment body 201 whose lower end is inserted into the low groove 103, and a segment steel bar 202 disposed on the segment body 201 with its upper end exposed, and used to connect to the upper pier segment.

[0049] In this embodiment, the segmental reinforcement 202 is the longitudinal reinforcement in the segmental reinforcement mesh cage. For most pier segments that are not at the bottom, both the upper and lower ends of the segmental reinforcement 202 need to be exposed to connect the segmental reinforcement 202 of adjacent pier segments.

[0050] In addition, the segmental steel mesh cage mainly includes longitudinal steel bars, horizontal circular steel bars, and radial connecting steel bars, and the segmental body 201 is the concrete used for the pouring of the bridge pier segment.

[0051] The outer UHPC steel pipe unit 3 includes a steel pipe 301 sleeved on the segment body 201, an open ring 302 disposed on the outer ring surface of the steel pipe 301 and used for inserting the anchor rod 104, and an annular UHPC layer 303 disposed on the outer ring surface of the steel pipe 301 and the upper surface of the open ring 302.

[0052] In this embodiment, UHPC refers to existing ultra-high performance concrete, which is poured in a ring and together with the steel pipe 301 can cover the bottom segment unit 2, providing the bottom segment unit 2 with a radially inward protective force.

[0053] Furthermore, the perforated ring 302 is located at the relative middle of the steel pipe 301, rather than at the end, ensuring that the tension force of the slotted support unit 1 on the bottom segment unit 2 has a relatively larger distribution area, reducing the probability of deformation or breakage of the bottom segment unit 2.

[0054] The outer UHPC steel pipe unit 3 also includes shear keys 304 disposed on the inner and outer annular surfaces of the steel pipe 301, which are used to reinforce and connect the segment body 201 and the annular UHPC layer 303 respectively.

[0055] In this embodiment, the shear key 304 includes inner and outer rings, which are used to reinforce the main body 201, steel pipe 301, and annular UHPC layer 303 as a whole.

[0056] The outer UHPC steel pipe unit 3 also includes circumferential reinforcing bars 305 disposed within the annular UHPC layer 303.

[0057] In this embodiment, the circumferential reinforcing bar 305 can appropriately improve the structural strength of the annular UHPC layer 303.

[0058] The anchor unit 4 includes an anchor nut 401 disposed on the anchor rod 104, and an anti-rust layer 402 disposed in the high groove 102 and used to cover the anchor rod 104 and the anchor nut 401.

[0059] In this embodiment, the anti-rust layer 402 is made of UHPC or epoxy mortar, ensuring that the anchor nut 401 and anchor rod 104 are not exposed. It is best to completely fill the high-level groove 102 in a flush manner.

[0060] The slotted foundation unit 1 further includes a foundation steel bar 105 disposed on the foundation body 101 and exposed on the bottom surface of the low-position groove 103; the bottom segment unit 2 further includes an inner recessed area 203 disposed within the outer UHPC steel pipe unit 3 and located below the segment body 201, used to accommodate the foundation steel bar 105, and a vertical channel 204 disposed on the segment body 201, used to add concrete to the inner recessed area 203 when connecting and pouring the segment steel bar 202.

[0061] In this embodiment, the foundation reinforcement 105 and the anchor rod 104 are essentially the longitudinal reinforcements of the foundation reinforcement mesh cage. The only difference is that the former is more central and shorter, while the latter has a unique threaded section.

[0062] Furthermore, a prefabricated concrete bridge pier cannot consist of only one pier segment. The upper end of the segmental steel bar 202 itself needs to be cast in place with concrete to connect to another pier segment. Therefore, the concrete is first poured at the vertical duct 204 until the inner recess 203 and the vertical duct 204 are filled, and finally the upper end of the segmental steel bar 202 is poured.

[0063] Therefore, for the bottom segment unit 2 and the slotted foundation unit 1, an additional concrete pouring connection effect is added.

[0064] The bottom segment unit 2 also includes a second circumferential reinforcing bar 205 disposed within the segment body 201 and used to connect the segment reinforcing bar 202, and the vertical channel 204 is disposed between two radially adjacent circles of the second circumferential reinforcing bar 205.

[0065] In this embodiment, no reinforcing bars are exposed in the vertical channel 204. Therefore, it is set between two adjacent radial rings of the second circumferential reinforcing bars 205 to ensure that the vertical channel 204 does not significantly reduce the structural strength of the bottom segment unit 2 itself.

[0066] Furthermore, the vertical channel 204 was not excavated later, but rather a circular channel was reserved by setting a ring of mesh cloth when pouring the main body of the segment 201.

[0067] A construction method for prefabricated concrete bridge piers using externally encased UHPC steel pipe connections includes the following steps:

[0068] S1. The outer UHPC steel pipe unit 3 is obtained by welding steel materials;

[0069] S2. Inside the outer UHPC steel pipe unit 3, a reinforcing cage is arranged, concrete is poured, and the bottom segment unit 2 is solidified to obtain a complete pier segment.

[0070] S3. The slotted foundation unit 1 is obtained by arranging steel reinforcement cages and pouring concrete.

[0071] S4. First, lift the pier segment, then insert the pier segment into the slotted pier unit 1 to obtain the pier body;

[0072] S5. Finally, the anchor unit 4 is tightened and poured on the main body of the pier to form the anchor unit 4, and the construction method of the prefabricated concrete pier with the single pier segment pattern is completed.

[0073] In S1 of this embodiment, the shear keys 304 and the perforated rings 302, one ring each on the inner and outer sides, need to be welded onto the steel pipe 301. The circumferential reinforcing bars 305 are then fixed by formwork, and finally the annular UHPC layer 303 is formed by casting.

[0074] In S2, when fabricating the segmental steel cage, sufficient staggered and exposed longitudinal bars should be left, namely segmental steel bars 202.

[0075] Finally, this embodiment has the following advantages.

[0076] First, the connection between the bottom segment and the pier cap includes at least three aspects: they are self-inserted, tied together by the outer UHPC steel pipe unit 3, and connected as a whole by the concrete and pier cap reinforcement 105 at the inner recess 203. Therefore, when the pier is subjected to lateral impact, the pier segments are not easily tilted, deformed, cracked, or disintegrated, resulting in relatively high structural strength and better structural integrity.

[0077] Secondly, this prefabricated concrete bridge pier essentially achieves relatively high structural strength by using a partial prefabrication method, while minimizing the amount of cast-in-place work.

[0078] Third, the outer UHPC steel pipe unit 3 can directly reinforce the bottom segment unit 2, and also provide a relatively central tie position with a sufficiently large stress area for the connection structure between the segment and the foundation, ensuring that the bottom segment unit 2 is not easy to tip over.

[0079] Fourth, the bottom segment unit 2 and the slotted foundation unit 1 have both the initial plug-in effect and the subsequent concrete pouring connection to form a whole, ensuring that even without the outer UHPC steel pipe unit 3, the bottom segment unit 2 can provide long-term stable support.

[0080] Fifth, the outer UHPC steel pipe unit 3 is securely installed on the bottom segment unit 2, and the radial reinforcement effect is sufficient, making the bottom segment unit 2 less prone to radial breakage or cracking.

[0081] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various modifications can be made without departing from the spirit of the present invention. These are non-inventive modifications and are protected by patent law as long as they fall within the scope of the claims of the present invention.

Claims

1. A prefabricated concrete bridge pier using externally encased UHPC steel pipe connections, characterized in that: The structure includes a slotted foundation unit (1), a bottom segment unit (2) inserted into the slotted foundation unit (1), an outer UHPC steel pipe unit (3) sleeved on the bottom segment unit (2) and inserted into the slotted foundation unit (1), and an anchor unit (4) disposed on the slotted foundation unit (1) and used to install the outer UHPC steel pipe unit (3). The slotted foundation unit (1) includes a foundation body (101), a high slot (102) for setting the anchor unit (4) on the upper surface of the foundation body (101), a low slot (103) for inserting the bottom segment unit (2) on the bottom surface of the high slot (102), and an anchor rod (104) for inserting the outer UHPC steel pipe unit (3) on the foundation body (101) and exposed at the upper end in the high slot (102). The bottom segment unit (2) includes a segment body (201) whose lower end is inserted into the low groove (103), and a segment steel bar (202) disposed on the segment body (201) with its upper end exposed, and used to connect the upper pier segment. The outer UHPC steel pipe unit (3) includes a steel pipe (301) sleeved on the segment body (201), an open ring (302) disposed on the outer ring surface of the steel pipe (301) and used for inserting the anchor rod (104), and an annular UHPC layer (303) disposed on the outer ring surface of the steel pipe (301) and the upper surface of the open ring (302). The outer UHPC steel pipe unit (3) also includes shear keys (304) disposed on the inner and outer annular surfaces of the steel pipe (301) and used to reinforce the connection between the segment body (201) and the annular UHPC layer (303). The outer UHPC steel pipe unit (3) also includes circumferential reinforcing bars (305) disposed within the annular UHPC layer (303). The slotted foundation unit (1) also includes a foundation steel bar (105) disposed on the foundation body (101) and exposed on the bottom surface of the low-level groove (103); the bottom segment unit (2) also includes an inner recess (203) disposed in the outer UHPC steel pipe unit (3) and located below the segment body (201) for accommodating the foundation steel bar (105), and a vertical channel (204) disposed on the segment body (201) for adding concrete to the inner recess (203) when connecting and casting the segment steel bar (202).

2. The prefabricated concrete bridge pier using external UHPC steel pipe connection as described in claim 1, characterized in that: The anchor unit (4) includes an anchor nut (401) disposed on the anchor rod (104) and an anti-rust layer (402) disposed in the high groove (102) and used to cover the anchor rod (104) and the anchor nut (401).

3. A prefabricated concrete bridge pier using an external UHPC steel pipe connection as described in claim 1, characterized in that: The bottom segment unit (2) also includes a second circumferential steel bar (205) disposed within the segment body (201) and used to connect the segment steel bar (202), and the vertical channel (204) is disposed between two radially adjacent circles of the second circumferential steel bar (205).

4. A construction method for prefabricated concrete bridge piers using external UHPC steel pipe connections as described in claim 1, characterized in that... The steps are as follows: S1. The outer UHPC steel pipe unit (3) is obtained by welding steel. S2. Inside the outer UHPC steel pipe unit (3), a steel cage is arranged and concrete is poured to solidify and form the bottom segment unit (2), thus obtaining a complete pier segment. S3. The slotted foundation unit (1) is obtained by arranging steel cages and pouring concrete. S4. First, lift the pier segment, and then insert the pier segment into the slotted pier unit (1) to obtain the pier body; S5. Finally, tighten and pour the anchor unit (4) on the main body of the pier to form the anchor unit. The construction method of the prefabricated concrete pier of a single pier segment is completed.

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