A deepwater group pile foundation reinforcement cage and a design method thereof

Abstract

The present application relates to the technical field of bridge engineering, and particularly relates to a deep water group pile foundation reinforcement cage and a design method thereof, the deep water group pile foundation reinforcement cage comprising: a plurality of vertical main reinforcements, each vertical reinforcement comprising a standard section, a gradual change section and an anchoring section, the standard sections of the plurality of vertical main reinforcements being arranged in a uniform interval around the center of the pile foundation section, the anchoring sections corresponding to the standard sections being located above the top surface of the pile foundation, and being arranged in the nearest gap among a plurality of gaps formed by longitudinal horizontal reinforcements and transverse horizontal reinforcements arranged in a uniform interval at a set interval, the gradual change section being located between the corresponding standard section and the anchoring section and being bent at a set angle relative to the standard section and the anchoring section. The problems that the horizontal reinforcement of the bottom surface of the pile foundation is difficult to be arranged through the pile foundation reinforcement cage and the interval of the horizontal reinforcement is uneven, and the concrete is difficult to be poured densely in the area with a dense interval due to the difficulty in vibration can be solved.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering technology, specifically to a deep-water pile foundation reinforcement cage and its design method. Background Technology

[0002] With the rapid development of my country's transportation infrastructure, the construction of cross-sea bridges is gradually shifting from nearshore to deep-sea areas. The number of projects is increasing, their scale is expanding, and the construction environments are becoming more complex and diverse. Harsh marine environments such as hurricanes, deep water, rapid currents, and strong swells pose significant challenges to bridge construction, particularly in the design and construction technology of deep-water bridge foundations.

[0003] High-pier pile foundations, as a commonly used form of deep-water foundation, are widely used in my country's cross-sea bridge projects due to their mature technology, rich construction experience, and relatively low construction risks. Compared to inland river bridges, the main difference in deep-water foundations for cross-sea bridges lies in the more severe hydrological and meteorological conditions. The foundations must be able to withstand the enormous horizontal forces generated by typhoons, giant waves, and high tides, and resist the impact forces of large ocean-going vessels. Due to the variable weather, strong winds, deep water, and high waves at sea, the permissible duration of underwater construction operations for cross-sea bridge foundations is relatively short. For high-pier pile foundations, under horizontal loads, the location of the largest bending moment often occurs at the pile top, and the structural strength is controlled by bending resistance, requiring a large amount of reinforcement at the pile top. To reduce the impact of wave currents on the pile foundation, reduce scouring at the pier location, and meet the requirements of drilling construction and borehole stability, bridge pile foundations typically adopt a circular cross-section. The main reinforcement bars of the pile foundation's steel cage are arranged uniformly in a circular circumferential direction and anchored within the pile cap. The longitudinal and transverse horizontal reinforcement bars at the bottom of the pile cap need to pass through the area of ​​the pile foundation's steel cage. Because the main reinforcement bars of the pile foundation's steel cage are arranged uniformly in a circular circumferential direction, the projected width of the net distance between adjacent main reinforcement bars in the same pile foundation decreases continuously from the center to both sides. When the projected width is smaller than the diameter of the horizontal reinforcement bars at the bottom of the pile cap, it becomes difficult for the horizontal reinforcement bars at the bottom of the pile cap to pass smoothly through the steel cage. This blind spot is even larger when the pile foundation's steel cage is configured with two or more rings of main reinforcement bars due to stress requirements.

[0004] In harsh marine environments with severe wave and current conditions, to reduce the wave and current forces on the foundation and decrease its size, the foundation cap is typically designed with a streamlined shape, such as a pointed or rounded end. The piles are then arranged in a staggered pattern. However, this staggered arrangement further increases the blind zone width where horizontal reinforcement cannot penetrate the pile reinforcement cage throughout the foundation area. The horizontal reinforcement at the bottom of the foundation is usually truncated within this blind zone, failing to maintain its continuous length, which is detrimental to the structural stress. For deep-water foundations of long-span bridges, multiple layers of horizontal reinforcement are often required on the bottom surface of the foundation. To allow this horizontal reinforcement to penetrate the pile reinforcement cage, the spacing of the horizontal reinforcement at the bottom of the foundation often becomes uneven, ultimately having a significant negative impact on the quality of the foundation concrete pouring. Areas with densely spaced reinforcement cannot be vibrated, making it difficult to pour a dense concrete.

[0005] Meanwhile, the corrosive environment of cross-sea bridges is even harsher. To ensure the durability of the bridge structure, epoxy-coated steel bars are often used for the pier cap reinforcement. However, epoxy-coated steel bars have high construction requirements. To avoid damage to the epoxy coating, the main reinforcement bars at the bottom of the pier cap must not rub against the pile foundation reinforcement cage. This undoubtedly increases the construction difficulty of the horizontal reinforcement bars at the bottom of the pier cap, extends the construction period, and makes it difficult to guarantee the construction quality of the pier cap. The layout of the horizontal reinforcement bars at the bottom of the pier cap of large cross-sea bridge pile foundations has always been a difficult problem to solve on-site, especially the problem of the horizontal reinforcement bars at the bottom of the pier cap not being able to pass smoothly through the blind zone of the pile foundation reinforcement cage.

[0006] To address this engineering challenge, a relatively good existing solution is to gradually transform the pile foundation's cross-section from circular to square over a certain length at the pile top, ensuring a square cross-section at the bottom of the pile cap. The arrangement of the main reinforcement bars in the pile foundation's steel cage also changes from a circular, evenly spaced arrangement to a square, evenly spaced arrangement. This technique ensures that the horizontal reinforcement bars at the bottom of the pile cap can pass smoothly through the pile foundation's steel cage, eliminating blind spots. However, this method has limitations. It has strict requirements for the design elevation of the bottom of the steel casing. Once the bottom elevation of the steel casing is determined in the design, the casing must be driven to the design elevation during construction; otherwise, it cannot be guaranteed that the transition from a circular to a square cross-section at the pile top is within the design requirements. Furthermore, the geological conditions encountered during the driving of the steel casing are often complex and diverse, making it difficult to guarantee that the steel casing for every pile can be driven to the design elevation. Additionally, this technique requires the steel casing to gradually transform from a circular to a square cross-section at the pile top, making the manufacturing of the transition section of the steel casing technically demanding and challenging. Summary of the Invention

[0007] In view of the deficiencies in the existing technology, the purpose of this invention is to provide a deep-water pile foundation reinforcement cage and its design method, which can solve the problems of the high construction difficulty of the horizontal reinforcement bars on the bottom surface of the pile cap passing through the pile foundation reinforcement cage, the uneven spacing of the horizontal reinforcement bars on the bottom surface of the entire pile cap, and the difficulty of pouring dense concrete in areas with denser reinforcement bars because they cannot be vibrated.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] On one hand, the present invention provides a steel reinforcement cage for a deep-water pile foundation, comprising:

[0010] Multiple vertical main reinforcement bars, each of which includes a standard section, a transition section, and an anchorage section. The standard sections of the multiple vertical main reinforcement bars are arranged at uniform intervals around the center of the pile foundation section. The anchorage section corresponding to the standard section is located above the top surface of the pile foundation and is used to pass through the nearest gap among multiple gaps formed by the longitudinal and transverse horizontal reinforcement bars of the bottom surface of the pile cap arranged at a set interval. The transition section is located between the corresponding standard section and the anchorage section and is bent at a set angle relative to the standard section and the anchorage section.

[0011] On the other hand, the present invention also provides a method for designing a reinforcing cage for a deep-water pile foundation, which includes the following steps:

[0012] The number of bars and the circumferential spacing of the standard section are determined based on the circumferential radius of the standard section and the spacing of the longitudinal and transverse horizontal bars on the bottom surface of the foundation.

[0013] Based on the positional relationship between the standard section and the corresponding anchorage section, determine the distance between the projections of the standard section and the anchorage section on the plane;

[0014] The length and bending angle of the gradient section are determined based on the height of the gradient section and the distance between the projections of the standard section and the anchoring section on the plane.

[0015] In some alternative solutions, according to the formula: n=4*Int((2*π*R) x ) / (4* △ L)) determines the number of circumferential roots n for the standard section, where Int() is the floor function; π is pi; R x The radius of the circumferential arrangement of the vertical main reinforcement bars. △ L represents the circumferential spacing of the standard section.

[0016] In some alternative solutions, according to the formula: △ L=(2*π*R x ) / (4*Int((2*π*R x ) / (4*△ S))), determine the circumferential spacing of the standard segment. △ L; where Int() is the floor function; π is pi; R x The radius of the circumferential arrangement of the vertical main reinforcement bars. △ S represents the spacing between longitudinal horizontal bars or the spacing between transverse horizontal bars.

[0017] In some alternative schemes, the circumferential spacing of the standard segment is set. △ L should satisfy △ L≥80+d1 mm, where d1 is the outer diameter of the thread in the standard section.

[0018] In some alternative schemes, the angle between the line connecting the center of the standard section of the first vertical main reinforcement and the center of the pile foundation section and the longitudinal axis of symmetry of the pile foundation section is: θ = 180° / n or 0°, where n is the number of vertical main reinforcement bars.

[0019] In some alternative solutions, according to the formula:

[0020] Determine the distance 'a' between the projections of the standard section and the anchorage section of the i-th vertical main reinforcement bar on the plane. i , where (x ni y ni Let (x) be the plane coordinates of the projection of the standard segment of the i-th vertical main reinforcement, and (x) be the coordinates of the projection. mi y mi ) represents the planar coordinates of the projection of the i-th vertical main reinforcement anchorage segment.

[0021] In some alternative solutions, according to the formula: Determine the length b of the transition section in the i-th vertical main reinforcement. i H is the height of the transition section.

[0022] In some alternative schemes, according to the formula: β i =arctan(a i / H), determine the bending angle β of the transition section in the i-th vertical main reinforcement. i In the formula, arctan() is the arctangent trigonometric function.

[0023] In some alternative solutions, according to the formula: H = k* △ S; determines the height of the transition section, where, △ S is the spacing between longitudinal horizontal bars or the spacing between transverse horizontal bars, and k is an adjustment coefficient with a value range of 6.0 to 10.0.

[0024] Compared with existing technologies, the advantages of this invention are as follows: The anchorage section of the vertical main reinforcement is designed based on the coordinates of the nearest gap center among multiple gaps formed by the longitudinal and transverse horizontal reinforcements evenly spaced at predetermined intervals on the bottom surface of the pile cap. Furthermore, the spacing of these gaps is consistent with the spacing of the longitudinal and transverse horizontal reinforcements on the bottom surface of the pile cap. The standard section of the vertical main reinforcement is evenly spaced circumferentially with the center of the pile foundation cross-section as the center, which better adapts to the circular cross-section of the pile. The transition section of the vertical main reinforcement linearly connects the standard section and the anchorage section, forming a complete pile foundation reinforcement cage. Therefore, during construction, the longitudinal and transverse horizontal reinforcements on the bottom surface of the pile cap can smoothly pass through the entire width of the pile foundation reinforcement cage, i.e., the anchorage section of the vertical main reinforcement. There are no blind spots within the width of the pile foundation reinforcement cage where the horizontal reinforcements on the bottom surface of the pile cap cannot pass through. All longitudinal and transverse horizontal reinforcements on the bottom surface of the pile cap do not need to be cut off; they can all maintain their continuous length, and the spacing between the reinforcements is uniform and appropriate. The construction difficulty of longitudinal and transverse horizontal reinforcement bars at the bottom of the foundation is reduced, the quality of foundation concrete pouring is guaranteed, the stress is better, and the construction period of the foundation is shortened. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic elevation view of the deep-water pile foundation reinforcement cage structure provided in an embodiment of the present invention;

[0027] Figure 2 for Figure 1 Schematic diagram of the cross-section of AA;

[0028] Figure 3 for Figure 1 Schematic diagram of the cross-section of BB;

[0029] Figure 4 for Figure 1 A schematic diagram of the cross-section of CC.

[0030] Figure 5 This is a schematic diagram showing the arrangement of longitudinal and transverse horizontal reinforcing bars on the bottom surface of the foundation in an embodiment of the present invention;

[0031] Figure 6 This is a schematic diagram showing the positional relationship between the standard section and the horizontal reinforcing bar in a planar projection according to an embodiment of the present invention;

[0032] Figure 7This is a schematic diagram showing the positional relationship between the planar projection of the anchorage section and the horizontal reinforcing bar in an embodiment of the present invention;

[0033] Figure 8 This is a schematic diagram illustrating the establishment of a rectangular coordinate system with the center of the pile foundation section in an embodiment of the present invention;

[0034] Figure 9 This is a schematic diagram of the standard segment numbering in an embodiment of the present invention;

[0035] Figure 10 This is a schematic diagram showing the numbering of the anchoring sections in an embodiment of the present invention;

[0036] Figure 11 This is a detailed schematic diagram of the i-th vertical main reinforcement bar in an embodiment of the present invention.

[0037] Figure 12 This is a schematic elevation view of a deep-water pile foundation structure provided in an embodiment of the present invention;

[0038] Figure 13 This is a plan view of a deep-water pile foundation structure provided in an embodiment of the present invention.

[0039] In the diagram: 1. Standard section; 11. Standard section stirrups; 2. Gradient section; 21. Gradient section stirrups; 3. Anchorage section; 4. Pile foundation; 5. Pile cap; 6a. Longitudinal horizontal reinforcement; 6b. Transverse horizontal reinforcement. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0042] like Figures 1-4 ,as well as Figure 12 and 13As shown, in one aspect, the present invention provides a deep-water pile foundation reinforcement cage, comprising: multiple vertical main bars, each vertical main bar including a standard section 1, a transition section 2, and an anchorage section 3. The standard section 1 of the multiple vertical main bars is arranged at uniform intervals around the center of the pile foundation 4 section; the anchorage section 3 corresponding to the standard section 1 is located above the top surface of the pile foundation 4, and is used to pass through the nearest gap center among multiple gaps formed by the longitudinal horizontal bars 6a and transverse horizontal bars 6b of the bottom surface of the pile cap arranged at a set interval; the transition section 2 is located between the corresponding standard section 1 and anchorage section 3, and is bent at a set angle relative to the standard section 1 and anchorage section 3.

[0043] In this embodiment, the anchorage section 3 of the vertical main reinforcement is designed according to the coordinates of the nearest gap center among the multiple gaps formed by the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b evenly spaced at a set interval on the bottom surface of the foundation, and the arrangement spacing is consistent with the arrangement spacing of the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b on the bottom surface of the foundation 5. The standard section 1 of the vertical main reinforcement is evenly spaced around the center of the pile foundation 4 section, which can better adapt to the circular cross-section of the pile foundation 4. The transition section 2 linearly connects the standard section 1 and the anchorage section 3 one by one to form a complete pile foundation reinforcement cage. Therefore, during construction, the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b on the bottom surface of the foundation can pass smoothly through the range of the pile foundation reinforcement cage, that is, the full width range of the anchorage section 3 of the vertical main reinforcement. There is no blind spot within the width range of the pile foundation reinforcement cage where the horizontal reinforcement on the bottom surface of the foundation cannot pass through. Moreover, all the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b on the bottom surface of the foundation 5 do not need to be cut off and can all be kept continuous, and the reinforcement spacing is uniform and appropriate. The construction difficulty of the longitudinal horizontal reinforcement 6a and the transverse horizontal reinforcement 6b on the bottom surface of the foundation 5 is reduced, the quality of the foundation concrete pouring is guaranteed, the stress is better, and the construction period of the foundation is shortened.

[0044] In this embodiment, the standard segment 1, the transition segment 2, and the anchoring segment 3 are connected in sequence and form a complete vertical main reinforcement bar. The transition segment 2 is bent during the design and manufacturing process.

[0045] In this embodiment, the number of circumferential roots n in standard segment 1 is determined according to n = 4 * Int((2 * π * R) x ) / (4* △ L)) is determined, where Int() is the floor function; π is the value of pi; R x R is the radius of the circumferential arrangement of the vertical main reinforcement bars. When two or more rings of vertical main reinforcement bars are arranged, R is... x The radius of the innermost main reinforcement bar arranged circumferentially; △ L represents the spacing of the circumferential reinforcement in standard section 1. When two or more rings of vertical main reinforcement are arranged, △ L represents the spacing of the innermost vertical main reinforcement bars arranged circumferentially.

[0046] The vertical main reinforcement bars can be arranged in two or more rings, with the number of vertical main reinforcement bars in each ring remaining equal. Maintaining the same number of vertical main reinforcement bars in each ring can eliminate the mutual obstruction effect between the inner and outer rings of vertical main reinforcement bars, ensuring smooth concrete flow during pile foundation construction and improving the quality of the pile body.

[0047] Circumferential spacing of standard section 1 △ L according to △ L=(2*π*R x ) / (4*Int((2*π*R x ) / (4* △ S))) is determined, where Int() is the floor function; π is the mathematical constant pi; R x The radius of the circumferential arrangement of the vertical main reinforcement bars. △ S represents the spacing between longitudinal horizontal reinforcing bars 6a or transverse horizontal reinforcing bars 6b. When two or more rings of vertical main reinforcing bars are arranged, R... x The radius of the innermost vertical main reinforcement bars arranged circumferentially; △ L represents the spacing of the vertical main reinforcement bars arranged circumferentially. When two or more rings of vertical main reinforcement bars are arranged, △ L represents the spacing of the innermost vertical main reinforcement bars arranged circumferentially.

[0048] Circumferential spacing of standard section 1 △ L should satisfy △ L≥80+d1 mm, where d1 is the outer diameter of the thread in standard section 1. All parameters are in millimeters.

[0049] When standard section 1 is arranged at equal intervals around the pile foundation section, the angle between the line connecting the center of standard section 1 and the center of pile foundation section 4 and the longitudinal axis of symmetry of pile foundation section 4 is: θ = 180° / n or 0°, where n is the number of vertical main bars.

[0050] The distance between the projections of standard segment 1 and anchorage segment 3 of the i-th vertical main reinforcement bar on the plane is: Among them, (x ni y ni Let (x) be the plane coordinates of the projection of the standard segment 1 of the i-th vertical main reinforcement, and (x) be the coordinates of the projection. mi y mi ) represents the planar coordinates of the projection of the i-th vertical main reinforcement anchorage segment 3.

[0051] The length of the transition segment 2 in the i-th vertical main reinforcement is: H is the height of gradient segment 2.

[0052] The bending angle of the transition segment 2 in the i-th vertical main reinforcement is β. i =arctan(a i / H).

[0053] The height H of the transition segment 2 is determined by H = k * △ S is determined. △ S is the spacing between longitudinal horizontal bars 6a or transverse horizontal bars 6b, and k is an adjustment coefficient with a value range of 6.0 to 10.0.

[0054] In addition, outside the vertical main reinforcement bars arranged in a ring, standard section stirrups 11 and transition section stirrups 21 are respectively provided in the standard section 1 and transition section 2 areas.

[0055] like Figures 5-11 As shown, on the other hand, the present invention also provides a design method for a reinforcing cage for a deep-water pile foundation, used to design the parameters of the aforementioned reinforcing cage for a deep-water pile foundation, comprising the following steps:

[0056] like Figure 5 and Figure 6 As shown, S1: Based on the circumferential radius of standard section 1 and the spacing of longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b, determine the number of bars in standard section 1 and the circumferential spacing.

[0057] Specifically, according to the formula: n=4*Int((2*π*R) x ) / (4* △ L)) determines the number of single-loop elements n in the standard section 1 circumferential setting, where Int() is the floor function; π is pi; R x The radius of the circumferential arrangement of the vertical main reinforcement bars. △ L represents the spacing of the standard section 1 arranged in a circumferential pattern. When two or more loops of standard section 1 are arranged, R... x The radius of the innermost standard section 1 arranged in a circumferential direction;

[0058] △ L represents the spacing of the standard section 1 arranged in a circumferential pattern. When two or more rings of standard section 1 are arranged, △ L represents the spacing of the innermost standard segment 1 arranged in a circumferential manner.

[0059] The aforementioned limitation on the number of single-ring bars in standard section 1 ensures that the planar arrangement of the vertical main bars in the entire pile foundation reinforcement cage has 1 / 8 symmetry, which can greatly reduce the types of vertical main bar details in the reinforcement cage (up to n / 8 types). Therefore, it can reduce the workload of processing and manufacturing the main bar details and improve work efficiency.

[0060] According to the formula: △ L=(2*π*R x ) / (4*Int((2*π*R x ) / (4* △ S))), determine the circumferential spacing of standard section 1. △L; where Int() is the floor function; π is pi; R x The radius of the circumferential arrangement of the vertical main reinforcement bars. △ S represents the spacing between longitudinal horizontal reinforcing bars 6a or transverse horizontal reinforcing bars 6b. When two or more rings of vertical main reinforcing bars are arranged, R... x The radius of the innermost vertical main reinforcement bars arranged circumferentially; △ L represents the spacing of the vertical main reinforcement bars arranged circumferentially. When two or more rings of vertical main reinforcement bars are arranged, △ L represents the spacing of the innermost vertical main reinforcement bars arranged circumferentially.

[0061] Circumferential spacing of standard section 1 △ As defined above, L ensures that the spacing between it and the horizontal reinforcement bars on the bottom surface of the foundation 5 is basically equal, thereby ensuring that the distance between the anchorage section 3 and the corresponding standard section 1 is controlled to a small value, making the bending angle between the transition section 2 and the standard section 1 and the anchorage section 3 smaller, and ensuring the smooth force transmission between the entire vertical main reinforcement bars.

[0062] Circumferential spacing of standard section 1 △ L satisfies △ L≥80+d1, where d1 is the outer diameter of the thread in standard section 1.

[0063] By limiting the circumferential spacing of standard section 1, it can be ensured that the coarse aggregate in the concrete can pass smoothly through the gap between adjacent main reinforcement bars during the concrete pouring process, thus ensuring the quality of the pile body.

[0064] The angle between the line connecting the center of the first standard section 1 and the center of the pile foundation section 4 and the longitudinal axis of symmetry of the pile foundation section 4 is: θ = 180° / n or 0°, where n is the number of vertical main reinforcement bars.

[0065] By defining the orientation of the standard section 1 of the first vertical main reinforcement, it is possible to ensure that the planar arrangement of the vertical main reinforcement of the entire pile foundation reinforcement cage is symmetrical about the longitudinal and transverse centerlines of the pile section, thus providing conditions for the uniform and evenly spaced longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b on the bottom surface of the pile cap 5.

[0066] S2: Determine the distance between the projections of the standard segment 1 and the corresponding anchoring segment 3 on the plane based on the positional relationship between the standard segment 1 and the corresponding anchoring segment 3.

[0067] like Figure 8 As shown, during the design process, a Cartesian coordinate system is first established with the center of the pile foundation section as the origin O(0,0), the transverse centerline of the section as the x-axis (positive to the right), and the longitudinal centerline as the y-axis (positive upward).

[0068] like Figure 9As shown, the planar layout of standard segment 1 in the first quadrant of the coordinate system, i.e., the planar layout of 1 / 4 standard segment 1, is selected. The main reinforcement bars in this part are numbered sequentially in a clockwise direction, such as n1, n2, n3, ... n j-1 n j And calculate the plane coordinates of each numbered main reinforcement bar, for any number n i The plane coordinates of the main reinforcement are (x ni y ni ).

[0069] like Figure 5 As shown, with the transverse and longitudinal centerlines of the pile foundation section 4 as the axis of symmetry, the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b on the bottom surface of the pile cap 5 are evenly arranged at a set interval. Figure 6 As shown, with the center of section 4 of the pile foundation as the center, in Figure 5 Based on this, a set number of standard sections 1 are arranged circumferentially at equal intervals. According to the relative relationship between the planar projection of standard section 1 and the planar projections of the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b on the bottom surface of the foundation 5, the planar projection of each standard section 1 is moved to the nearest center of the square gap enclosed by the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b, thus forming the planar arrangement of the anchorage section 3, as follows: Figure 7 As shown. When projecting onto the plane of standard section 1, the principle is to ensure the minimum protective layer thickness of the reinforcing steel. For example... Figure 10 As shown, the planar arrangement of anchorage segment 3 in the first quadrant of the coordinate system, i.e., the planar arrangement of 1 / 4 anchorage segment 3, is selected. The main reinforcement bars in this part are numbered sequentially in a clockwise direction, such as m1, m2, m3, ... m j-1 m j And calculate the plane coordinates of each numbered main reinforcement bar, for any number m i The plane coordinates of the main reinforcement are (x mi y mi ).

[0070] Calculate the distance 'a' between the projections of standard segment 1 and anchorage segment 3 in the plane corresponding to the numbered sections, which is the distance 'a' between the projections of standard segment 1 and anchorage segment 3 in the plane of the i-th vertical main reinforcement. In the formula, (x ni y ni Let (x) be the plane coordinates of the standard segment 1 of the i-th vertical main reinforcement. mi y mi ) represents the plane coordinates of the i-th vertical main reinforcement anchorage segment 3.

[0071] like Figure 11 As shown, S3: Determine the length and bending angle of the gradient section 2 based on the height of the gradient section 2 and the distance between the projections of the standard section 1 and the anchoring section 3 on the plane.

[0072] Based on the distance 'a' between the projections of the corresponding numbered standard segment 1 and anchorage segment 3 on the plane, and the height 'H' of the transition segment 2, calculate the detailed length 'b' of each numbered transition segment 2, which is the detailed length of the transition segment 2 in the i-th vertical main reinforcement.

[0073] Based on the distance 'a' between the projections of standard segment 1 and anchorage segment 3 on the plane, and the height 'H' of transition segment 2, the bending angle 'β' of each numbered transition segment 2 is calculated. That is, the bending angle 'β' of transition segment 2 in the i-th vertical main reinforcement bar. i =arctan(a i / H), where arctan() is the arctangent trigonometric function. The bending angle of the transition segment 2 refers to the bending angle β between the transition segment 2 and the standard segment 1 and the anchoring segment 3, such as Figure 11 As shown.

[0074] According to the formula: H=k* △ S determines the height of transition segment 2, where... △ S is the spacing between longitudinal horizontal bars 6a or transverse horizontal bars 6b, and k is an adjustment coefficient with a value range of 6.0 to 10.0.

[0075] When fabricating and installing the deep-water pile foundation reinforcement cage: according to the length of the large-scale drawing corresponding to each vertical main reinforcement number, and the bending angle β between the corresponding transition section 2, standard section 1 and anchorage section 3, each numbered vertical main reinforcement is processed and manufactured. After processing, each numbered vertical main reinforcement is installed on the reinforcement cage jig at the set position, and then stirrups are welded on the outer surface of the vertical main reinforcement to form the reinforcement cage.

[0076] Because the anchorage section 3 of the vertical main reinforcement in the pile foundation reinforcement cage is designed according to the coordinates of the nearest gap center among the multiple gaps formed by the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b evenly spaced at a set interval on the bottom surface of the pile cap, and the arrangement spacing is consistent with the arrangement spacing of the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b on the bottom surface of the pile cap 5; the standard section 1 of the vertical main reinforcement is evenly spaced around the center of the pile foundation 4 section, which can better adapt to the circular cross-section of the pile foundation 4; the transition section 2 linearly connects the standard section 1 and the anchorage section 3 one by one to form a complete pile foundation reinforcement cage body. Therefore, during construction, the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b on the bottom surface of the pile cap can smoothly pass through the range of the pile foundation reinforcement cage, that is, the full width range of the anchorage section 3 of the vertical main reinforcement. There is no blind spot within the width range of the pile foundation reinforcement cage where the horizontal reinforcement on the bottom surface of the pile cap cannot pass through, and all the longitudinal horizontal reinforcement 6a and transverse horizontal reinforcement 6b on the bottom surface of the pile cap 5 do not need to be cut off, and can all be kept continuous, with uniform and appropriate spacing between the reinforcements. The construction difficulty of the longitudinal horizontal reinforcement 6a and the transverse horizontal reinforcement 6b on the bottom surface of the foundation 5 is reduced, the quality of the foundation concrete pouring is guaranteed, the stress is better, and the construction period of the foundation is shortened.

[0077] In existing technologies, from a construction sequence perspective, the installation of horizontal reinforcement at the bottom of the pile cap is carried out after the pile foundation construction is completed. The arrangement of the horizontal reinforcement at the bottom of the pile cap needs to adapt to the arrangement of the main reinforcement in the pile foundation cage in order to pass through the cage's range. However, since the main reinforcement in the pile foundation cage is usually arranged in a uniform circular pattern, there is a certain width of blind zone, making it difficult for the horizontal reinforcement at the bottom of the pile cap 5 to pass smoothly through the cage's range, especially when the pile foundation has two or more rings of main reinforcement, the blind zone is even larger. Normally, during the construction of the horizontal reinforcement at the bottom of the pile cap 5, the main reinforcement in the cage or the pile cap reinforcement is bent on-site to pass through the blind zone. However, for the main tower foundation of large cross-sea bridges, the diameter of the reinforcement in the pile top section is often quite large due to structural stress requirements, reaching 40mm or even 50mm. Similarly, the horizontal reinforcement at the bottom of the pile cap has many layers and a large diameter, making it too difficult to construct by bending the main reinforcement in the pile foundation or the pile cap reinforcement on-site, which is simply not feasible. Furthermore, the horizontal reinforcement bars of the pile cap that pass smoothly through the non-blind zone of the reinforcement cage have a spacing that gradually decreases from the center of the pile foundation section to both sides. The spacing of the reinforcement bars is uneven, and the concrete is difficult to be poured densely in areas where the reinforcement bars are densely spaced because they cannot be vibrated.

[0078] like Figure 12 and 13As shown, to solve this technical problem, a reverse design approach is adopted. First, the planar layout of the horizontal reinforcement at the bottom of the pile cap 5 is designed, followed by the planar layout of the vertical main reinforcement of the pile foundation. This is achieved by adjusting the arrangement of the main reinforcement of the pile foundation cage during the design phase to accommodate the uniformly spaced horizontal reinforcement at the bottom of the pile cap 5, rather than the conventional method of moving the horizontal reinforcement at the bottom of the pile cap during construction to accommodate the uniformly spaced circumferential vertical reinforcement of the pile foundation cage. In this technical solution, the longitudinal horizontal reinforcement 6a and the transverse horizontal reinforcement 6b at the bottom of the pile cap 5 are arranged at normal equal intervals. The vertical main reinforcement of the pile foundation cage is arranged uniformly at equal intervals within the pile body using a conventional ring pattern. At the pile top section at the bottom of the pile cap 5, the arrangement is adjusted to a row-and-column pattern, meaning the vertical main reinforcement of the cage passes through the gaps formed by the horizontal reinforcement at the bottom of the pile cap 5. The change from the conventional ring-and-column arrangement to the row-and-column arrangement of the main reinforcement of the cage is achieved through local bending within a certain height range at the pile top. The processing and manufacturing of the transition section is completed in the steel reinforcement processing plant through precise layout, ensuring manufacturing accuracy and construction quality. Using the technical solution provided by this invention, all longitudinal and transverse horizontal steel bars on the bottom surface of the foundation 5 can smoothly pass through the pile foundation reinforcement cage, ensuring uniform longitudinal and transverse spacing and appropriate density, guaranteeing the quality of the foundation concrete pouring, and reducing on-site construction difficulty.

[0079] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not 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 application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0080] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0081] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A steel reinforcement cage for a deep-water pile foundation, characterized in that, include: Multiple vertical main bars, each of which includes a standard section (1), a transition section (2) and an anchorage section (3). The standard section (1) of the multiple vertical main bars is arranged in a circumferentially evenly spaced manner with the center of the pile foundation (4) section as the center. The anchorage section (3) corresponding to the standard section (1) is located above the top surface of the pile foundation (4). The planar projection of each standard section (1) is moved to the center of the nearest square gap formed by the longitudinal horizontal steel bar (6a) and the transverse horizontal steel bar (6b) to form the planar arrangement of the anchorage section (3). The transition section (2) is located between the corresponding standard section (1) and the anchorage section (3) and is bent at a set angle relative to the standard section (1) and the anchorage section (3).

2. A method for designing a reinforcing cage for a deep-water pile foundation, characterized in that, The method for designing the steel reinforcement cage for a deep-water pile foundation as described in claim 1 includes the following steps: Based on the circumferential radius of the standard section (1) and the spacing of the longitudinal horizontal reinforcement (6a) and transverse horizontal reinforcement (6b) on the bottom surface of the foundation, determine the number of bars and the circumferential spacing of the standard section (1). Based on the positional relationship between the standard segment (1) and the corresponding anchoring segment (3), determine the distance between the projections of the standard segment (1) and the anchoring segment (3) on the plane; The length and bending angle of the gradient segment (2) are determined based on the height of the gradient segment (2) and the distance between the projections of the standard segment (1) and the anchoring segment (3) on the plane.

3. The deep-water pile foundation reinforcement cage design method as described in claim 2, characterized in that, According to the formula: n=4*Int((2*π*R) x ) / (4* △ L)), determine the number of circumferential roots n in the standard segment (1), where Int() is the floor function; π is pi; R x The radius of the circumferential arrangement of the vertical main reinforcement bars. △ L is the circumferential spacing of the standard segment (1).

4. The deep-water pile foundation reinforcement cage design method as described in claim 3, characterized in that, According to the formula: △ L=(2*π*R x ) / (4*Int((2*π*R x ) / (4* △ S))), determine the circumferential spacing of the standard segment (1). △ L; where Int() is the floor function; π is pi; R x The radius of the circumferential arrangement of the vertical main reinforcement bars. △ S represents the spacing between longitudinal horizontal bars (6a) or transverse horizontal bars (6b).

5. The deep-water pile foundation reinforcement cage design method as described in claim 3 or 4, characterized in that, The circumferential spacing of the standard segment (1) △ L should satisfy △ L≥80+d1mm, where d1 is the outer diameter of the thread in the standard section (1).

6. The deep-water pile foundation reinforcement cage design method as described in claim 3, characterized in that, The angle between the line connecting the center of the standard section (1) of the first vertical main reinforcement and the center of the pile foundation (4) section and the longitudinal axis of symmetry of the pile foundation (4) section is: θ = 180° / n or 0°, where n is the number of vertical main reinforcement bars.

7. The deep-water pile foundation reinforcement cage design method as described in claim 2, characterized in that, According to the formula: a i = Determine the distance a between the projections of the standard segment (1) and the anchorage segment (3) on the plane in the i-th vertical main reinforcement. i , where (x ni y ni Let (x) be the plane coordinates of the projection of the standard segment (1) of the i-th vertical main reinforcement, and (x) be the coordinates of the projection. mi y mi ) is the plane coordinate of the projection of the i-th vertical main bar anchorage segment (3).

8. The deep-water pile foundation reinforcement cage design method as described in claim 2, characterized in that, According to the formula: b i = Determine the length b of the transition segment (2) in the i-th vertical main reinforcement. i H is the height of the gradient segment (2).

9. The deep-water pile foundation reinforcement cage design method as described in claim 2, characterized in that, According to the formula: β i =arctan(a i / H), determine the bending angle β of the transition segment (2) in the i-th vertical main reinforcement. i In the formula, arctan() is the arctangent trigonometric function.

10. The method for designing a reinforced cage for a deep-water pile foundation as described in claim 8 or 9, characterized in that, According to the formula: H=k* △ S; Determine the height of the transition segment (2), where, △ S is the spacing between longitudinal horizontal bars (6a) or transverse horizontal bars (6b), and k is an adjustment coefficient with a value range of 6.0 to 10.0.

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