A scour-resistant bridge pier pile foundation structure, construction device and construction method

Abstract

This invention belongs to the field of bridge engineering technology, specifically disclosing an anti-scour bridge pier pile foundation structure, construction device, and construction method. The pier pile foundation structure includes a pile foundation and a UHPC casing located outside the pile foundation, with a pile cap supporting the pile foundation. The bottom end of the UHPC casing is located 1m below the scour elevation of the riverbed, and the top end is located at the low water level elevation. The UHPC casing is made of ultra-high performance concrete, the portion of the pile foundation below the pile cap is made of recycled concrete, and the portion of the pile foundation entering the pile cap is made of ordinary concrete. The anti-scour bridge pier pile foundation structure of this invention uses UHPC to protect the easily scourized parts of the pier, reducing the damage to the bottom of the pier caused by seawater scouring, soaking, and atmospheric corrosion, improving the service life of the pier, and significantly reducing the probability of cracking and structural deformation under load.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering technology, and in particular relates to an anti-scour bridge pier pile foundation structure, construction device and construction method. Background Technology

[0002] my country's bridge construction entered a period of rapid development starting in the last century, with the scale and complexity of bridge construction continuously increasing. In recent years, to promote economic development between the mainland's coastal areas and nearby islands, the number of large-scale cross-sea bridges has been steadily increasing. However, the corrosion and erosion of bridge piers by seawater has become a major challenge, requiring my country to invest substantial funds annually in the repair of marine engineering projects.

[0003] Due to seawater erosion, immersion, and atmospheric corrosion, the reinforced concrete piers of cross-sea bridges are susceptible to chloride ion corrosion, leading to rapid deterioration of their durability and even structural damage. The problems of seawater erosion and corrosion in marine engineering projects such as cross-sea bridge piers are becoming increasingly prominent, mainly manifested as the peeling of the concrete protective layer and the corrosion and exposure of reinforcing steel.

[0004] While significant research has been achieved both domestically and internationally in the theory and practice of resisting scour damage to bridge piers in rivers, research on seawater scour and corrosion of bridge piers under marine environmental conditions is still limited. In particular, there is no effective solution to the damage problem between the normal water level and the scour elevation of cross-sea bridge piers.

[0005] Chinese invention patent CN111236291B discloses a NACA-type water injection device and its construction method for scour prevention of tandem pile foundations for bridge piers. The water injection device includes a NACA airfoil structure and several fixed piles. The cross-section of the NACA airfoil structure is NACA airfoil-shaped. The NACA airfoil structure is provided with pile foundation insertion holes with NACA airfoil-shaped cross-sections. The NACA airfoil structure is fitted onto the outer surface of the tandem pile foundation through the pile foundation insertion holes and is fixed by several fixed piles. Since the outer perimeter of the tandem pile foundation in contact with water is wrapped by the NACA airfoil structure, it can effectively suppress the damage of horseshoe vortices and wake vortices to the tandem pile foundation, ensure that the pile foundation is not scoured or corroded by water, and improve the bearing capacity of the tandem pile foundation.

[0006] However, the aforementioned patent protects the exposed portion of the pile foundation by wrapping it, leaving a large gap between the pile foundation and the NACA airfoil mechanism. This only solves the problem of water erosion and cannot prevent corrosion. At the same time, it cannot improve the bearing capacity of the pile foundation itself, and has certain limitations and room for improvement. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes an anti-scour bridge pier pile foundation structure, construction device, and construction method, aiming to solve or improve at least one of the aforementioned technical problems.

[0008] To achieve the above objectives, in one aspect, the present invention provides an anti-scour bridge pier pile foundation structure, comprising a pile foundation and a UHPC casing located outside the pile foundation, wherein a pile cap is supported on the pile foundation; the bottom end of the UHPC casing is located 1m below the scour elevation of the riverbed, and the top end is located at the low water level elevation; the UHPC casing is made of ultra-high performance concrete; the portion of the pile foundation located below the pile cap is made of recycled concrete; and the portion of the pile foundation entering the pile cap is made of ordinary concrete.

[0009] Based on the aforementioned pier pile foundation structure, UHPC casing is used as a protective layer between the scour elevation and the low water level. Compared to reinforced concrete structures, it offers higher resistance to corrosion and erosion, improving structural safety and durability. It also effectively reduces cracking at the pier base. Furthermore, UHPC is a high-performance material, and combining it with reinforced concrete structures enhances load-bearing capacity. Recycled concrete is used in the cast-in-place pile foundation section, reusing some construction waste, aligning with green construction and sustainable development principles. The cost of recycled aggregate concrete of the same grade is also slightly lower than that of ordinary concrete, saving on project costs.

[0010] Preferably, the top of the UHPC casing extends into the support platform. For example, it can extend 15 cm into the platform.

[0011] Preferably, the portion of the pile foundation that enters the pile cap is inverted conical.

[0012] Preferably, the bottom end of the UHPC casing is higher than the bottom end of the pile foundation, the bottom end of the UHPC casing is located 1m below the scour elevation, and the bottom end of the pile foundation is located at the designed elevation of the pile foundation.

[0013] Compared with the prior art, the present invention has the following advantages and technical effects: the anti-scour pier pile foundation structure of the present invention uses UHPC to protect the easily scourable parts of the pier, which can reduce the damage to the bottom of the pier caused by seawater scouring, soaking, and atmospheric corrosion, improve the service life of the pier, and significantly reduce the probability of cracking of the pier and its structural deformation under load.

[0014] On the other hand, the present invention also provides a bridge pier pile foundation construction device for the construction of scour bridge pier pile foundation structures according to any of the above claims, comprising an inner casing and an outer casing, wherein the outer casing is fitted around the inner casing with a gap and is coaxial with the inner casing, one end of the outer casing is located more than 1m below the scour elevation of the riverbed, the bottom end of the inner casing is higher than the outer casing, and the top end of the inner casing extends a certain distance beyond the top of the outer casing; the inner casing includes multiple clamps, the sides of the multiple clamps are detachably connected in sequence to form a complete cylinder, and has a smooth outer surface.

[0015] Preferably, the inner side of the clamp is provided with a connecting edge, and a connecting hole is opened on the connecting edge. The connecting holes of two adjacent clamps are in corresponding positions and are fastened together by high-strength bolts.

[0016] Preferably, a rubber strip is used to seal between two adjacent clamps.

[0017] Preferably, all of the said clamps are identical in shape and size.

[0018] Preferably, four clamps are provided.

[0019] The aforementioned construction device employs two steel casings, inner and outer, to separately pour the pile foundation concrete and the UHPC casing. The tops of the inner and outer casings are slightly higher than the normal water level, with the top of the inner casing slightly higher than the top of the outer casing. The bottom of the inner casing is higher than the bottom of the outer casing, and the bottom of the outer casing is more than one meter lower than the scour elevation. The inner casing uses an inner clamping method with the same diameter as the pile foundation. The gaps in the clamping are sealed with rubber strips to prevent concrete from flowing out.

[0020] Furthermore, the present invention also provides a method for constructing bridge pier pile foundations, using the bridge pier pile foundation construction device described in any of the above claims, comprising the following steps:

[0021] S1. Install the outer casing; drive the outer casing into the construction location to at least 1m below the scour elevation, remove the soil inside the outer casing, pour the bottom sealing concrete, and pump out the water inside the casing.

[0022] S2. Install the inner casing;

[0023] S3. Install the UHPC casing steel cage;

[0024] S4. Pour UHPC and cure for more than one week to form UHPC casing;

[0025] S5. Remove the inner casing and apply external restraints;

[0026] S6. Use an impact hammer to strike the bottom sealing concrete inside the UHPC casing, and continue excavating the pile foundation to the design elevation;

[0027] S7. Pour the pile foundation concrete to form the pile foundation;

[0028] S8. Pour the foundation stone to complete the construction. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a front view of the structure of the pile foundation and UHPC casing in an embodiment of the present invention;

[0031] Figure 2 This is a three-dimensional structural view of the pile foundation and UHPC casing in an embodiment of the present invention.

[0032] Figure 3 This is a three-dimensional structural view of the pile foundation and UHPC casing in an embodiment of the present invention from another perspective;

[0033] Figure 4 This is a top view of the pile foundation and UHPC casing in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of a steel pipe pile constraining a UHPC casing according to an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the reinforcement of the pile foundation facade structure according to an embodiment of the present invention;

[0036] Figure 7 for Figure 6 Cross-sectional view at point AA;

[0037] Figure 8 This is an elevation view of the reinforcement of the UHPC casing according to an embodiment of the present invention;

[0038] Figure 9 This is a cross-sectional view of the reinforcement of the UHPC casing according to an embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of the connection between the pile foundation and the pile cap according to an embodiment of the present invention;

[0040] Figure 11 This is a plan view of the reinforcement arrangement of the foundation in an embodiment of the present invention;

[0041] Figure 12 This is an elevation view of the reinforcement arrangement of the foundation in an embodiment of the present invention;

[0042] Figure 13 for Figure 11 Cross-sectional view at point BB.

[0043] The components are: 1. UHPC casing; 2. Inner casing; 3. Outer casing; 4. Pile foundation; 5. Pile foundation reinforcement cage; 51. Pile foundation stirrups; 52. Pile foundation longitudinal reinforcement; 6. Reinforcing stirrups; 7. Pile cap; 8. Pile cap reinforcement; 9. UHPC casing longitudinal reinforcement; 10. UHPC casing stirrups; 11. Rubber strip; 12. Bottom sealing concrete; 13. Clamping hoop; 14. High-strength bolt; 15. Steel pipe pile; 16. Restraining steel pipe; 17. Restraining clamping hoop. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Example 1:

[0047] refer to Figures 1 to 13 Embodiment 1 of the present invention provides an anti-scour bridge pier pile foundation structure and construction device. The anti-scour bridge pier pile foundation structure includes a pile foundation 4, with a UHPC casing 1 surrounding the pile foundation 4. The height of the pile foundation 4 is greater than that of the UHPC casing 1. The bottom end (the end extending into the riverbed) of the UHPC casing 1 is approximately 1m below the scour elevation, preferably 1m, and the top end (near the water) is located at a low water level elevation. The cast-in-place section of the pile foundation 4 uses recycled concrete, while the pier section uses ordinary concrete. Figures 1-4 The diagram shows a structural schematic of the pile foundation 4 and UHPC casing 1 during construction of the scour-resistant bridge pier pile foundation structure. From the inside out, the pile foundation 4, inner casing 2, UHPC casing 1, and outer casing 3 are sequentially nested. The diameter of the inner casing 2 is smaller than that of the outer casing 3, and the inner and outer casings are coaxially and concentrically arranged, forming a gap between them. The UHPC casing 1 is poured into this gap. The inner casing 2 is removed before the pile foundation 4 is poured. The outer casing 3 can be considered part of the scour-resistant bridge pier pile foundation structure in this embodiment and is not removed. A pile cap 7 is connected above the pile foundation 4 and the UHPC casing 1. Figure 10 As shown, the UHPC casing 1 is 15cm higher than the bottom surface of the pier cap 7; the part of the pile foundation 4 located below the pier cap 7 is the cast-in-place section, which is cast with recycled concrete. The part of the pile foundation 4 that extends into the pier cap is the pier section, which is cast with ordinary concrete. This part extends into the pier cap 7 for a certain length and is a support structure in the shape of an inverted cone.

[0048] Specifically, the inner casing 2 and the outer casing 3 are made of steel. The top of the inner casing 2 is higher than the top of the outer casing 3, and the bottom of the inner casing 2 is also slightly higher than the bottom of the outer casing 3. The bottom of the outer casing 3 is at least 1m lower than the scour elevation.

[0049] Specifically, the inner casing 2 adopts the form of an inner clamp, the diameter of the inner casing is the same as that of the pile foundation 4, and the gaps of the clamp 13 are sealed with rubber strips 11.

[0050] Furthermore, multiple clamps 13 are provided, and the sides of each clamp 13 are sequentially spliced ​​together to form a complete cylinder. In this embodiment, four clamps are preferred. Figure 2 and Figure 3 As shown, the cross-section of the four clamps 13 is a quarter circle, and the sides are provided with connecting edges extending radially towards the center of the circle. Connecting holes are opened on the connecting edges, and the connecting holes of two adjacent clamps 13 are in corresponding positions. They are fastened together with high-strength bolts 14, and the gap between the two connecting edges is sealed with rubber strips 11 to prevent concrete leakage.

[0051] Specifically, UHPC casing 1 is constructed using ultra-high performance concrete (UHPC), an innovative cement-based composite material. Unlike ordinary concrete, it does not use coarse aggregate but instead employs silicate cement, silica fume, quartz powder, fine silica sand, high-efficiency water-reducing agents, water, steel fibers, or organic fibers as raw materials. It features a high cement content and a low water-cement ratio, exhibiting high strength, high ductility, corrosion resistance, and wear resistance. Using UHPC casing 1 between the scour elevation and the normal water level provides superior corrosion and erosion resistance compared to reinforced concrete structures, improving structural safety and durability. It effectively reduces cracking at the pier base. Furthermore, as a high-performance material, combining UHPC with reinforced concrete structures also enhances load-bearing capacity.

[0052] Specifically, the UHPC casing 1 is filled with UHPC steel reinforcement, which consists of UHPC longitudinal bars 9 standing upright along the axial direction of the UHPC casing 1 and UHPC casing stirrups 10 arranged circumferentially inside the UHPC casing 1. The UHPC longitudinal bars 9 and UHPC casing stirrups 10 are tied together to form the UHPC steel reinforcement.

[0053] Specifically, the bottom of the inner casing 3 is sealed with underwater concrete to form a bottom sealing concrete 12. The bottom sealing height does not exceed the scour elevation, and the bottom sealing concrete 12 also serves to fix the inner casing 2.

[0054] Specifically, the pile foundation 4 includes recycled concrete and a pile foundation reinforcement cage 5 poured inside the recycled concrete; the recycled concrete includes a portion of construction waste that has been recycled and reused, as well as recycled aggregates, and its cost is lower than that of ordinary concrete, which can save some project costs and is in line with the current concept of green construction and sustainable development; the pile foundation reinforcement cage 5 includes pile foundation longitudinal bars 52 and pile foundation stirrups 51, the pile foundation longitudinal bars 52 are arranged along the axial direction of the pile foundation 4, and the pile foundation stirrups 51 are arranged circumferentially on the outer periphery of the pile foundation longitudinal bars 52; the pile foundation reinforcement cage 5 is also connected to a reinforcing hoop 6, which is arranged circumferentially on the inner periphery of the pile foundation longitudinal bars 52.

[0055] Specifically, the foundation 7 includes foundation reinforcement 8, which consists of horizontally and vertically interlocking steel bars. The horizontal and vertical steel bars are connected to form a grid structure, such as... Figures 11-13 As shown.

[0056] Embodiment 1 of this invention aims to propose a novel scour-resistant bridge pier pile foundation structure. The main damaged sections between the normal water level and the scour line of the riverbed are encased in UHPC (Ultra-High-Pressure Polymer) to prevent the pier from being damaged by seawater scouring and corrosion, thereby increasing the pier's service life and reducing the probability of cracking in the concrete at the pier base. To prevent excessive stiffness difference between the pile foundation and the pier, the remaining parts of the pile foundation are constructed using recycled concrete, while the pier itself uses ordinary concrete. Using UHPC to protect the scour-prone areas of the pier can mitigate the damage to the pier base caused by seawater scouring, soaking, and atmospheric corrosion, thus improving the pier's service life and significantly reducing the probability of cracking and structural deformation under load.

[0057] Example 2:

[0058] The following is combined Figures 1 to 13 The present invention describes the construction method for bridge pier pile foundations.

[0059] Embodiment 2 of this invention proposes a construction method for bridge pier pile foundations. This method involves pouring a UHPC (Ultra-High-Pressure Polymer) casing 1 between the inner casing 2 and the outer casing 3, and then pouring pile foundation concrete into the UHPC casing 1 to form the pile foundation 4, thus completing the construction of the cast-in-place section below the pile cap 7. During construction, the outer casing 3 is first driven in to at least 1m below the scour elevation. The mud and sand inside the outer casing 3 are removed, the bottom of the casing is sealed with concrete, and any accumulated water inside is pumped out. Then, the inner casing 2 is installed. The inner casing 2 uses an inner clamp design, with the same diameter as the pile foundation 4. Gaps in the clamp 13 are sealed with rubber strips 11 to prevent concrete leakage. After the inner casing 2 is installed, the UHPC casing reinforcement cage is lowered between the inner casing 2 and the outer casing 3, and the UHPC is then poured. After one week of curing, the inner casing 2 is removed. Steel pipe piles 15 and restraining steel pipes 16 are used to restrain and protect the UHPC casing 1. Then, an impact hammer is used to strike the bottom sealing concrete 12 inside the UHPC casing 1. The pile foundation 4 continues to be excavated to the design elevation. To prevent the UHPC casing from falling during further drilling, restraining clamps 17 are used to support its weight. After the pile foundation 4 is drilled, the lower pile foundation reinforcement cage is placed, and pile foundation concrete is poured, completing the construction of pile foundation 4. Finally, the foundation cap 7 is constructed above pile foundation 4 and the UHPC casing 1. During the construction of foundation cap 7, the concrete at the end of pile foundation 4 is chiseled out to allow for better bonding between the cast-in-place concrete of pile foundation 4 and the concrete of the upper foundation cap. Foundation reinforcement 8 and formwork are erected, and concrete is poured to complete the construction of foundation cap 7.

[0060] Specifically, the following steps are included:

[0061] S1. Install outer casing 3; drive outer casing 3 into the construction position to at least 1m below the scour elevation, remove the soil inside outer casing 3, seal the bottom of the casing with concrete, pour bottom sealing concrete 12, and pump out the water inside the casing.

[0062] S2. Install the inner casing 2; The inner casing 2 adopts the form of an inner clamp, and the inner casing 2 with the same diameter as the pile foundation 4 is rotated and placed on the bottom sealing concrete 12 coaxially with the outer casing 3.

[0063] S3. Install the UHPC casing reinforcement cage; install the UHPC casing reinforcement cage in the gap between the inner casing 2 and the outer casing 3;

[0064] S4. Casting UHPC: Pour UHPC into the gap between the inner casing 2 and the outer casing 3 to form UHPC casing 1, and cure for more than one week.

[0065] S5. Remove inner casing 2; After one week of curing, remove inner casing 2 from UHPC casing 1. Externally constrain UHPC casing 1 using steel pipe piles 15 and restraining steel pipes 16, while simultaneously using clamps to support the weight of the UHPC. Figure 5 As shown;

[0066] S6. Use an impact hammer to strike the bottom sealing concrete 12 inside the UHPC casing 1, and continue to excavate the pile foundation 4 to the design elevation to form the pile foundation hole;

[0067] S7. Pour the pile foundation 4; Lower the pile foundation steel cage 5 into the UHPC casing 1 to the design elevation, pour concrete, and complete the construction of pile foundation 4.

[0068] S8. Cast the foundation 7; erect the foundation reinforcement 8 and formwork above the pile foundation 4, and cast the foundation concrete to complete the construction of foundation 7.

[0069] The beneficial effects of this invention are as follows: The anti-scour pier pile foundation structure of this invention uses UHPC as a protective layer. Using UHPC material in the parts of the pier that are mainly subjected to seawater scouring and corrosion can reduce the damage of seawater to the pier, improve the durability of the pier, and significantly reduce the probability of concrete cracking in the pier area and its structural deformation under load. The cast-in-place pile foundation section uses recycled concrete, which conforms to current green building practices while saving on project costs.

[0070] All aspects not detailed in this invention are conventional technical means known to those skilled in the art.

[0071] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0072] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A bridge pier pile foundation construction device for constructing scour-resistant bridge pier pile foundation structures, characterized in that... The system includes an inner casing (2), an outer casing (3), and a UHPC casing (1). The UHPC casing (1) is located outside the pile foundation (4). The outer casing (3) is coaxially sleeved outside the inner casing (2). An annular gap for casting the UHPC casing (1) is formed between the inner casing (2) and the outer casing (3). One end of the outer casing (3) extends more than 1m below the scour elevation of the riverbed. The bottom of the inner casing (2) is higher than the outer casing (3). The top of the inner casing (2) extends a distance beyond the top of the outer casing (3). The inner casing (2) includes multiple clamps (13). The sides of the multiple clamps (13) are detachably connected in sequence to form a complete cylinder with a smooth outer surface.

2. The bridge pier pile foundation construction device according to claim 1, characterized in that, The inner side of the clamp (13) is provided with a connecting edge, and a connecting hole is opened on the connecting edge. The connecting holes of two adjacent clamps (13) are in corresponding positions and are fastened together by high-strength bolts (14).

3. The bridge pier pile foundation construction device according to claim 2, characterized in that, A rubber strip (11) is used to seal between two adjacent clamps (13).

4. The bridge pier pile foundation construction device according to claim 1, characterized in that, The multiple clamps (13) are all the same in shape and size.

5. The bridge pier pile foundation construction device according to claim 4, characterized in that, The clamps (13) are configured as four.

6. The bridge pier pile foundation construction device according to claim 1, characterized in that, The bottom end of the UHPC casing (1) is higher than the bottom end of the pile foundation (4), and the bottom end of the UHPC casing (1) is located at the scour elevation of 1m, while the bottom end of the pile foundation (4) is located at the design elevation of the pile foundation.

7. A method for constructing bridge pier pile foundations, characterized in that, Using the bridge pier pile foundation construction device as described in any one of claims 1 to 6, the following steps are performed: S1. Install the outer casing (3); drive the outer casing (3) into the construction position to at least 1m below the scour elevation, remove the soil inside the outer casing (3), pour the bottom sealing concrete (12), and pump out the water inside the casing; S2. Install the inner casing (2); S3. Install the UHPC casing steel cage; S4. Pour UHPC and cure for more than one week to form UHPC casing (1); S5. Remove the inner casing (2) and apply external restraints; S6. Use an impact hammer to strike the bottom sealing concrete inside the UHPC casing (1), and continue to excavate the pile foundation to the design elevation; S7. Pour the pile foundation concrete to form the pile foundation (4); S8. Pour the foundation (7) to complete the construction.

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