Rapid assembling and connecting structure of UHPC prefabricated pipe and bearing platform and construction method

Abstract

The invention discloses a rapid assembling and connecting structure of UHPC prefabricated pipes and a bearing platform and a construction method. The rapid assembling and connecting structure comprises connector assemblies (1), the UHPC prefabricated pipes (2), the bearing platform (3), joint sealing materials (4) and core concrete (5). The connector assembly includes a fixed end fastener and an adjustable end fastener. When the UHPC prefabricated pipe bottom fixing end fastener is close to the bearing platform adjustable end fastener, the UHPC prefabricated pipe bottom fixing end fastener and the bearing platform adjustable end fastener can be closed once collided, the UHPC prefabricated pipe and the bearing platform are rapidly positioned, and local fine adjustment is conducted through the adjustable end fastener. After the UHPC prefabricated pipe and the bearing platform are assembled, the joint sealing material is poured into a gap between the bearing platform and the UHPC prefabricated pipe, core concrete in the UHPC prefabricated pipe is poured before initial setting of the joint sealing material, and integrity of the bearing platform and the UHPC prefabricated pipe is guaranteed. Rapid positioning of the UHPC prefabricated pipe and the bearing platform is achieved, the formed connecting structure is high in anti-pulling performance and stable in structure, and reference can be provided for rapid splicing of an assembly type bridge.

Description

Technical Field

[0001] The present invention relates to a rapid assembly connection structure and construction method for a UHPC precast pipe and a bearing platform, belonging to the technical field of bridge structure construction. Background Art

[0002] Reinforced concrete bridge piers are widely used in bridge engineering due to their good applicability and economy. However, during long-term use, restricted by the mechanical properties and durability of materials, diseases such as oversized pier columns, poor seismic performance, and spalling of cover concrete and exposure of steel bars gradually emerge, seriously affecting the service performance of bridges. As a new type of cement-based material, UHPC has ultra-high strength, excellent fracture toughness, and good durability. Applying it to pier column members can not only effectively improve the bearing capacity of bridge piers, give full play to the anti-cracking function of the material itself, and make up for problems such as durability degradation caused by cracking of existing concrete structures; the ultra-high fracture toughness of UHPC can more effectively improve the elastoplastic energy dissipation capacity of pier column members, and thus achieve good seismic performance. However, considering that the cost of UHPC is relatively high at present, using a full UHPC structure is not conducive to its engineering promotion and application.

[0003] Based on this, many combined pier column structures based on UHPC materials, such as outer cylinder UHPC formwork columns - inner core reinforced concrete combined bridge piers, reactive powder concrete precast pipe columns, and UHPC externally wrapped reinforced concrete bridge piers, have been successively proposed. Researchers' studies on their seismic performance show that based on reasonable performance design, UHPC and NC combined pier columns not only have good economy, but also can give full play to the advantages of their respective materials. On the premise of ensuring the effective connection between the bridge pier and the bearing platform, good bearing characteristics and seismic expectations can be achieved.

[0004] At present, the connection structural forms between precast pipe bridge piers and bearing platforms mainly include traditional socket connections, grouting sleeve connections, etc. Although these connection methods can meet the engineering requirements to a certain extent, with the continuous development of bridge construction technology, the performance requirements for connection nodes are also getting higher and higher. However, due to the lack of reliable longitudinal connection keys, the traditional socket connection has poor uplift resistance, resulting in poor performance when bearing vertical loads and seismic actions. Moreover, both the traditional socket connection and the grouting sleeve connection cannot quickly position the precast bridge pier and the bearing platform, and cannot achieve local fine adjustment between the precast pipe and the bearing platform. Summary of the Invention

[0005] The purpose of the present invention is to propose a rapid assembly connection structure and construction method for a UHPC precast pipe and a bearing platform to solve the defects that the traditional socket connection and grouting sleeve connection between precast pipe bridge piers and bearing platforms cannot quickly position the precast bridge pier and the bearing platform and cannot achieve local fine adjustment between the precast pipe and the bearing platform.

[0006] The technical solution implemented by the present invention is as follows: a quick assembly connection structure of a UHPC prefabricated pipe and a cap, comprising a UHPC prefabricated pipe, a cap and a connector assembly. The UHPC prefabricated pipe and the cap are connected by a plurality of identical connector assemblies, and the plurality of connector assemblies are evenly distributed in the circumferential direction; each connector assembly comprises a fixed end fastener and an adjustable end fastener, the fixed end fastener is installed at the lower end of the UHPC prefabricated pipe, and the adjustable end fastener is installed at the bottom of the columnar groove of the cap, and when the fixed end fastener at the bottom of the UHPC prefabricated pipe is close to the adjustable end fastener of the cap, the two "touch and fit" to quickly position the UHPC prefabricated pipe and the cap; the caulking material is poured in the gap between the cap and the UHPC prefabricated pipe, and the core concrete inside the UHPC prefabricated pipe is poured before the caulking material is initially set to ensure the integrity of the cap and the UHPC prefabricated pipe.

[0007] The fixed end fastener is a connecting lock, one end of which is a lock base and the other end is a lock end. The lock end of the connecting lock is provided with a lock petal that can rotate around a fixed point; the adjustable end fastener includes a connecting lock, a positioner, a seat plate, a positioning hole and an adjustment hole; the connecting lock is the same shape and size as the connecting lock of the fixed end fastener, but in the opposite position; one end of the positioner is connected to the connecting lock, and the other end is connected to the seat plate; the two ends of the positioner are hollow, and the cross section is like an "I" shape, which is sleeved on the slender splint on the upper part of the seat plate. The slender splint is provided with a positioning hole and an adjustment hole. The positioning bolts penetrate the positioning holes of the positioner and the splint at the same time, which is used for clamping and fixing and realizing local fine-tuning of the adjustable end fastener. When adjusting, loosen the positioning bolts and adjust the positioning holes on the upper and lower positions of the two splints to achieve the required docking height.

[0008] When the connecting lock of the fixed end fastener is connected with the connecting lock of the adjustable end fastener, the locking petals will be embedded in the grooves of the opposite side locks. When the locking petals are completely embedded in place, the push iron in the fastener will fall down, locking the moving space of the locking petals to prevent the locking petals from returning and falling out in the reverse direction, thereby locking the UHPC prefabricated pipe and the base into a whole.

[0009] The positioning steel plate at the lower end of the UHPC prefabricated pipe is welded to the steel cage as a whole before casting the UHPC prefabricated pipe. The positioning steel plate is perpendicular to the center line of the UHPC prefabricated pipe. The UHPC prefabricated pipe is cast by a centrifugal process.

[0010] A columnar groove perpendicular to the horizontal plane is provided at the center of the top of the support platform, and the distance between the wall of the UHPC prefabricated pipe and the inner wall of the groove is 2-4 cm.

[0011] When fabricating the steel reinforcement cage of the bearing platform, the seat plate of the adjustable end fastener is embedded in the steel reinforcement cage, welded and fixed, and then concrete is poured to form a connection lock, with part of it exposed in the groove of the bearing platform; the seat plate of the adjustable end fastener is made of high-strength steel plate. While serving as the base for fixing the adjustable end fastener, it is embedded in the steel reinforcement cage of the bearing platform and acts as a shear key between the bearing platform and the UHPC precast pipe to jointly bear the force, enhancing the mechanical performance of the entire pier.

[0012] A construction method for a rapid assembly connection structure between a UHPC precast pipe and a bearing platform is as follows: (1) Prefabrication of UHPC precast pipe: First, fabricate the steel reinforcement cage of the UHPC precast pipe, embed 4 - 6 positioning steel plates at the lower end of the steel reinforcement cage, and then use the centrifugal forming process to pour the UHPC precast pipe; after demolding, cure it in an environment of 90°C for 48 hours, and then cool it to room temperature to form a hollow UHPC precast pipe with the lower surface of the positioning steel plate exposed. (2) Pouring of the bearing platform: Bind the steel reinforcement cage of the fabricated bearing platform, use the formwork to make a partition to reserve the position of the columnar groove; bury the lower part of the seat plate of the adjustable end fastener in the steel reinforcement cage, weld and fix it, and then pour the bearing platform. After the bearing platform is formed, remove the formwork. (3) Assembly of the UHPC precast pipe and the bearing platform: Make the base of the fixed end fastener fit on the positioning steel plate, weld and fix it to form a whole after determining the position; then lift the formed UHPC precast pipe above the bearing platform, adjust the positioner to pull the connection lock to the designed position, adjust the angle of the UHPC precast pipe until the fixed end fastener and the adjustable end fastener are vertically aligned, and slowly lower it after adjusting the positioner; after the connection locks at both ends are embedded in place and locked with each other, the UHPC precast pipe and the bearing platform are tightly combined to form a whole. (4) Forming of the splicing joint: When the assembly of the UHPC precast pipe and the bearing platform is completed, use caulking material to fill the gap between the UHPC precast pipe and the groove of the bearing platform until the height of the caulking material is flush with the bearing platform, and then vibrate it densely; before the caulking material starts to set, pour the core concrete inside the UHPC precast pipe, fill the UHPC precast pipe, and then vibrate it densely; thus, the rapid assembly connection between the UHPC precast pipe and the bearing platform is completed.

[0013] The beneficial effects of the present invention are as follows: The present invention realizes the precise positioning of the UHPC precast pipe and the bearing platform. By adjusting the position of the positioning steel plate embedded at the bottom of the UHPC precast pipe, the welding position of the fixed-end fastener is determined. When hoisting the UHPC precast pipe, the precise positioning of the socket position of the UHPC precast pipe is realized through the correspondence between the fixed-end fastener and the adjustable-end fastener. It avoids the deviation problem caused by the blind butt joint without reference in the traditional socket connection, and improves the overall quality of the combined bridge pier. When the fixed-end fastener and the adjustable-end fastener of the connector assembly of the present invention are in contact with each other, the locking petals of the connection lock will be embedded into the grooves of the opposite locking petals. When the locking petals are completely embedded in place, the push iron in the fastener will fall, locking the moving space of the locking petals. The UHPC precast pipe and the bearing platform are quickly connected and fixed through this ingenious collision, forming a firm whole.

[0014] The present invention realizes the firm connection between the UHPC precast pipe and the bearing platform through the connector assembly. The connection structure in the connector assembly that prevents the locking petals from retracting reversely has high anti-pulling performance, providing the first guarantee for the reliable connection between the UHPC precast pipe and the bearing platform. After the UHPC precast pipe and the bearing platform are connected and fixed, the present invention uses UHPC mortar to fill the gaps inside the columnar grooves, giving full play to the fracture toughness of UHPC and enhancing the bonding performance between the bearing platform and the UHPC precast pipe, providing the second guarantee for the reliable connection between the UHPC precast pipe and the bearing platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic cross-sectional structure diagram of an embodiment of the present invention; Figure 2 It is a schematic structural diagram of the connector assembly; Figure 3 It is a schematic structural diagram of the bearing platform; Figure 4 It is a schematic cross-sectional structure diagram of the bearing platform; Figure 5 It is a partial cross-sectional schematic diagram of an embodiment of the present invention; Figure 6 It is a sectional view A-A of an embodiment of the present invention; Figure 7 It is a schematic overall structure diagram of an embodiment of the present invention; Figure 8 For Figure 2 B-B view of In the figure: 1 is the connector assembly; 2 is the UHPC precast pipe; 3 is the bearing platform; 4 is the caulking material; 5 is the core concrete; 11 is the fixed-end fastener; 12 is the adjustable-end fastener; 21 is the positioning steel plate; 31 is the formwork; 32 is the columnar groove; 111 is the lock base; 121 is the connection lock; 122 is the positioner; 123 is the seat plate; 124 is the positioning hole; 125 is the adjustment hole; 126 is the positioning bolt. DETAILED DESCRIPTION

[0016] like Figure 1 As shown, a quick assembly connection structure of a UHPC prefabricated pipe and a cap in this embodiment includes a connector component 1, a UHPC prefabricated pipe 2, a cap 3, a filler 4 and a core concrete 5.

[0017] like Figure 2 As shown, the connector assembly 1 of this embodiment includes a fixed end fastener 11 and an adjustable end fastener 12. The fixed end fastener 11 is arranged at the lower end of the UHPC prefabricated tube 2, and the adjustable end fastener 12 is arranged at the bottom of the columnar groove 32 of the pedestal. When the fixed end fastener 11 at the bottom of the UHPC prefabricated tube is close to the adjustable end fastener 12 of the pedestal, the two "fit together as soon as they touch", quickly positioning the UHPC prefabricated tube 2 and the pedestal 3, and locally fine-tuning through the adjustable end fastener 12. After the UHPC prefabricated tube 2 and the pedestal 3 are assembled, the caulking material 4 is poured into the gap between the pedestal 3 and the UHPC prefabricated tube 2, and the core concrete 5 inside the UHPC prefabricated tube 2 is poured before the caulking material 4 begins to set, so as to ensure the integrity of the pedestal 3 and the UHPC prefabricated tube 2.

[0018] The core concrete 4 of the embodiment of the present invention can be cast using ordinary concrete or UHPC.

[0019] In the embodiment of the present invention, the UHPC prefabricated pipe 2 is prefabricated in a factory, and the casting template is adjusted during casting so that a toothed shear ring appears in the socket area of ​​the UHPC prefabricated pipe 2. After the UHPC prefabricated pipe 2 is assembled with the cap 3, the cement-based joint filler 4 is continuously cast in the columnar groove 32, and UHPC mortar is used for casting in the embodiment of the present invention.

[0020] like Figure 3 and Figure 4 As shown, in this embodiment, the cap is prefabricated in the factory. A corrugated pipe 31 is used as a partition, and a position for a columnar groove 32 is reserved. The corrugated pipe 31 is removed after the cap is cast. After the UHPC prefabricated pipe 2 is spliced, the concrete filler 4 is poured and vibrated to make it fit tightly with the inner wall of the cap and to fill the toothed shear ring at the bottom of the UHPC prefabricated pipe 2, which helps to enhance the bonding performance of the cap 3 and the UHPC prefabricated pipe 2 and achieve the construction effect of "equivalent to cast-in-place".

[0021] The structure of the connector assembly 1 in this embodiment is substantially the same as the James coupler structure used to connect trains.

[0022] like Figure 6 As shown, the connector assembly of this embodiment includes the fixed end fastener 11 fixedly welded on the positioning steel plate 21 at the lower end of the UHPC prefabricated pipe, the adjustable end fastener 12 partially embedded in the base, and other locking irons, locking flaps, etc. connecting the two fasteners.

[0023] like Figure 2 and Figure 5 As shown, a locking base 111 is provided at the top of the fixed end fastener 11 of this embodiment. When assembling, the locking base 111 is fitted with the positioning steel plate 21 provided at the lower end of the UHPC prefabricated tube 2, and the position is determined and then welded and fixed. The adjustable end fastener 12 is composed of a connecting lock 121, a positioner 122 and a seat plate 123, and is provided at the bottom of the columnar groove 32 of the cap. The connecting lock 121 is connected to the positioner 122 through a fixing hole.

[0024] The two ends of the positioner 122 of this embodiment are hollow, and the cross section is shaped like a Chinese character "工". Figure 8 As shown, the slender clamping plate sleeved on the upper part of the seat plate 123 is provided with a positioning hole 124 and an adjustment hole 125. The positioning bolt 126 penetrates the positioner 122 and the positioning hole 124 of the clamping plate at the same time, which is used for clamping and fixing and realizing local fine adjustment of the adjustable end fastener. When adjusting, loosen the positioning bolt 126 and adjust the positioning hole 124 in the upper and lower positions of the two clamping plates to achieve the required docking height.

[0025] like Figure 1 As shown, after the pedestal 3 and the UHPC prefabricated pipe 2 are manufactured, the UHPC prefabricated pipe 2 is hoisted above the pedestal 3, and the positioner 122 is adjusted to pull the connecting lock 121 to reach the designed position. When the fixed end fastener 11 at the bottom of the UHPC prefabricated pipe is close to the adjustable end fastener 12 of the pedestal, the two are "touched and engaged", and the UHPC prefabricated pipe 2 and the pedestal 3 are quickly positioned, and the adjustable end fastener 12 is used for local fine adjustment; when the fasteners are in contact, the lock petals will be embedded in the grooves of the opposite hook heads. When the lock petals are completely embedded in place, the push iron in the fastener will fall, locking the moving space of the lock petals, preventing the lock petals from returning in the reverse direction and falling out, and locking the UHPC prefabricated pipe 2 and the pedestal 3 to form a whole.

Claims

1. A rapid assembly and connection structure between a UHPC precast pipe and a bearing platform, comprising a UHPC precast pipe and a bearing platform, characterized in that, The structure further includes a connector assembly; the UHPC precast pipe and the bearing platform are connected by a plurality of identical connector assemblies, and the plurality of connector assemblies are evenly distributed in the circumferential direction; each connector assembly includes a fixed-end fastener and an adjustable-end fastener. The fixed-end fastener is installed at the lower end of the UHPC precast pipe, and the adjustable-end fastener is installed at the bottom of the columnar groove of the bearing platform. When the fixed-end fastener at the bottom of the UHPC precast pipe approaches the adjustable-end fastener of the bearing platform, the two "fit together instantly", quickly positioning the UHPC precast pipe and the bearing platform; the caulking material is poured into the gap between the bearing platform and the UHPC precast pipe, and the core concrete inside the UHPC precast pipe is poured before the caulking material begins to set, ensuring the integrity of the bearing platform and the UHPC precast pipe.

2. The quick assembly and connection structure of a UHPC precast pipe and a bearing platform according to claim 1, characterized in that, The fixed-end fastener is a connecting lock. One end is a lock base, and the other end is a lock end. The lock end of the connecting lock is provided with a lock flap that can rotate around a fixed point; the adjustable-end fastener includes a connecting lock, a positioner, a seat plate, a positioning hole, and an adjustment hole; the connecting lock of the adjustable-end fastener has the same shape and size as the connecting lock of the fixed-end fastener, but in the opposite position; one end of the positioner is connected to the connecting lock, and the other end is connected to the seat plate; the two ends of the positioner are hollow, and the cross-section is in the shape of a "work" character and is sleeved on the slender clamping plate on the upper part of the seat plate. The slender clamping plate is provided with a positioning hole and an adjustment hole. The positioning bolt passes through the positioning holes of the positioner and the clamping plate at the same time, for clamping and fixing and achieving local fine adjustment of the adjustable-end fastener; during adjustment, loosen the positioning bolt and adjust the up and down positions of the positioning hole on the two clamping plates to reach the required docking height.

3. The quick assembly and connection structure of a UHPC precast pipe and a bearing platform according to claim 1, characterized in that, The positioning steel plate at the lower end of the UHPC precast pipe is welded to the steel reinforcement cage as a whole before pouring the UHPC precast pipe. The positioning steel plate is perpendicular to the center line of the UHPC precast pipe, and the UHPC precast pipe is formed by centrifugal casting.

4. A rapid assembly and connection structure between a UHPC precast pipe and a bearing platform according to claim 1, characterized in that, A columnar groove perpendicular to the horizontal plane is provided at the center of the top of the bearing platform, and the distance between the inner wall of the groove and the wall of the UHPC precast pipe is 2-4 cm.

5. A rapid assembly and connection structure of a UHPC precast pipe and a bearing platform according to claim 1, characterized in that, The seat plate of the adjustable-end fastener is buried in the steel reinforcement cage during the preparation of the steel reinforcement cage of the bearing platform, welded and fixed, and then concrete is poured, so that the connecting lock part is exposed in the groove of the bearing platform; the seat plate of the adjustable-end fastener is made of high-strength steel plate. While serving as the base for fixing the adjustable-end fastener, it is buried in the steel reinforcement cage of the bearing platform and acts as a shear key between the bearing platform and the UHPC precast pipe to jointly bear the force, enhancing the mechanical properties of the entire pier.

6. The quick assembly and connection structure of a UHPC precast pipe and a bearing platform according to claim 2, characterized in that, When the connecting lock of the fixed-end fastener is connected to the connecting lock of the adjustable-end fastener, the lock flaps will be embedded in the grooves of the opposite-side lock. When the lock flaps are completely embedded in place, the push iron inside the fastener will fall, locking the moving space of the lock flaps, preventing the lock flaps from reversing and disengaging, and locking the UHPC precast pipe and the bearing platform to form a whole.

7. The construction method of the rapid assembly connection structure between the UHPC precast pipe and the bearing platform as described in any one of claims 1 to 6, characterized in that, The method steps are as follows: (1) Prefabrication of UHPC pipes: First, prepare the steel cage of the UHPC prefabricated pipe, and embed 4-6 positioning steel plates at the lower end of the steel skeleton, and then cast the UHPC pipe using the centrifugal forming process; after demolding, steam cure at 90℃ for 48h, and then cool to room temperature to form a hollow UHPC prefabricated pipe with the lower surface of the positioning steel plate exposed; (2) Casting of the cap: Tie and weave the steel frame of the cap, and use the template as a partition to reserve the position of the columnar groove; bury the lower part of the seat plate of the adjustable end fastener into the steel frame, weld and fix it, and then cast the cap. After the cap is formed, remove the template; (3) Splicing the UHPC prefabricated pipe and the cap: fit the base of the fixed end fastener onto the positioning steel plate, and weld and fix it to form a whole after determining the position; then hang the formed UHPC prefabricated pipe above the cap, adjust the positioner to pull the connecting lock buckle to the designed position, adjust the angle of the UHPC prefabricated pipe until the fixed end fastener and the adjustable end fastener are aligned up and down, and slowly drop it after adjusting the positioner; after the connecting lock buckles at both ends are embedded in place, they are locked with each other, so that the UHPC prefabricated pipe and the cap are tightly combined to form a whole; (4) Forming of the splicing joint: After the UHPC prefabricated pipe and the cap are assembled, fill the gap between the UHPC prefabricated pipe and the cap groove with filler until the filler is flush with the cap and then vibrate to make it dense; before the filler begins to set, pour the core concrete inside the UHPC prefabricated pipe, fill the UHPC prefabricated pipe and then vibrate to make it dense; thus, the quick assembly and connection of the UHPC prefabricated pipe and the cap are completed.

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