Reinforcing steel bar prestress detection device arranged in bearing platform and large-span prestress bearing platform

Abstract

The invention relates to the technical field of prestress detection, in particular to a bearing platform built-in steel bar prestress detection device and a large-span prestress bearing platform, the bearing platform built-in steel bar prestress detection device comprises a reaction frame, a pressure sensor and a tensioning jack, the pressure sensor is used for measuring pressure generated in the tensioning process, and a displacement sensor is used for measuring displacement of the tensioning jack in the tensioning process. The data acquisition system is electrically connected with the pressure sensor and the displacement sensor; a reversing assembly is arranged in the counter-force frame and comprises a supporting seat, a guide wheel and a steel strand, and the guide wheel and the tensioning jack are fixed to the two ends of the supporting seat respectively; one end of the steel strand is connected with the steel bar through the first connecting anchor head to form an inclined section, and the other end of the steel strand penetrates through the reaction frame and the pressure sensor to be connected with the tensioning jack through the second connecting anchor head to form a horizontal section. The reversing assembly can conduct tensioning in a multi-angle dense rib distribution area, the requirement for the operation space is reduced, the position of the guide wheel does not need to be adjusted frequently, and the project progress is accelerated.

Description

Technical Field

[0001] This invention relates to the field of prestressing testing technology, and in particular to a prestressing testing device for reinforcing steel bars installed inside a pier cap and a large-span prestressed pier cap. Background Technology

[0002] With the rapid development of urban underground infrastructure and the three-dimensional extension of surface transportation networks, complex spatial intersections between rail transit tunnel sections, integrated utility tunnels, municipal pipelines, and elevated bridge piers have become commonplace. To resolve the conflict between bridge foundations and underground structures, large-span prestressed concrete abutments are widely used as key load-bearing structures. Their large lateral span design achieves structural avoidance, greatly alleviating the problem of scarce urban space resources.

[0003] Effective prestress under the anchor is a core control indicator in bridge prestressed construction, directly determining the structural load-bearing capacity. Over-tensioning can easily lead to concrete crushing and beam deformation, while under-tensioning can cause deflection or even collapse. Currently, many hidden quality problems in bridges stem from inadequate quality control during prestressing tensioning construction. Therefore, it is essential to conduct prestress testing under the anchor in prestressed components.

[0004] Currently, the commonly used testing methods are the strain gauge method and the reverse tension method. The strain gauge method involves installing strain gauges or force sensors on the steel strands, but this method is susceptible to temperature drift and installation process variations, resulting in a sensor survival rate of less than 65% in long-term monitoring. The reverse tension method, on the other hand, involves applying a load again to the already tensioned steel bars outside the bridge structure to detect the effective prestress. Because the reverse tension method offers advantages such as high measurement accuracy, safe and simple operation, minimal influencing factors, no damage to the already tensioned prestressed structure, and repeatable testing, it is widely used in bridge construction testing.

[0005] However, the prestressed steel strands within the pier cap are typically arranged radially, with inclination angles ranging from 8° to 35°. This inclined arrangement of the prestressed steel strands presents a significant challenge to existing testing methods. Traditional counter-tensioning devices require the jacks to be tilted so that they are aligned with the steel strands, resulting in a larger working space for the jacks. In areas with dense reinforcement at multiple angles, tensioning operations are simply impossible. Furthermore, the tilt angle of the jacks is limited by the reaction frame, necessitating frequent adjustments to the reaction frame's posture for steel strands with different inclination angles, which severely impacts project progress. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a prestressed steel reinforcement detection device inside the pier cap and a large-span prestressed pier cap, which effectively solves the problems in the background art.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a prestressed steel reinforcement detection device and a large-span prestressed pier, comprising: a reaction frame, a pressure sensor, a tensioning jack, a displacement sensor and a data acquisition system;

[0008] The reaction frame, pressure sensor, and tensioning jack are arranged sequentially away from the bearing platform. The pressure sensor is used to measure the pressure generated during the tensioning process. The displacement sensor is installed at the exposed part of the hydraulic cylinder of the tensioning jack and is used to measure the displacement of the tensioning jack during the tensioning process. The data acquisition system is electrically connected to the pressure sensor and the displacement sensor to acquire the pressure value and the displacement value.

[0009] The reaction frame is equipped with a reversing component, which includes a support base, a guide wheel, and a steel strand. The guide wheel and the tensioning jack are respectively fixed at both ends of the support base.

[0010] One end of the steel strand is connected to the reinforcing bar through the first connecting anchor head, forming an inclined section that is collinear with the reinforcing bar. The other end of the steel strand is wrapped around the guide wheel to form a horizontal section that is collinear with the axis of the tensioning jack, and passes through the reaction frame and the pressure sensor in sequence, and is connected to the tensioning jack through the second connecting anchor head.

[0011] Furthermore, the reaction frame includes an outer frame and a plurality of partitions disposed inside the outer frame;

[0012] The outer edge of the end face of the outer frame that contacts the bearing platform extends toward the bearing platform, forming a positioning edge that circumferentially covers the outside of the bearing platform.

[0013] Furthermore, the reversing assembly also includes a lifting assembly that supports and drives the support seat to move in a vertical direction, the lifting assembly driving the support seat to adjust the height of the guide wheel.

[0014] Furthermore, the lifting assembly includes a lifting frame, a driving component, a first laser rangefinder, a second laser rangefinder, and a control unit;

[0015] The first laser rangefinder is installed on the contact surface between the pier and the reaction frame, and is set corresponding to the steel bar to be measured, in order to obtain the initial inclination angle of the steel bar to be measured;

[0016] The second laser rangefinder is installed on the inner top wall of the reaction frame to obtain the real-time angle of the inclined section of the steel strand;

[0017] The control unit receives feedback data from the first laser rangefinder and the second laser rangefinder, and controls the drive component to adjust the height of the lifting frame so that the inclined section of steel strand and the reinforcing bar remain collinear.

[0018] Furthermore, the bottom of the lifting assembly is provided with a sliding table;

[0019] The slide table includes a first slide rail group and a second slide rail group arranged perpendicular to the first slide rail group, both of which are arranged horizontally.

[0020] Furthermore, a third laser rangefinder is installed on both sides of the support base at the end where the guide wheel is mounted, for centering and calibrating the horizontal section of the steel strand.

[0021] Furthermore, the first connecting anchor head includes a first anchoring clamp connected to the steel strand and a second anchoring clamp connected to the reinforcing bar;

[0022] Both the first anchoring clamp and the second anchoring clamp include an anchoring clip and an anchoring steel sleeve sleeved on the outside of the anchoring clip. The anchoring steel sleeve has a threaded section and a necking section inside. The necking section causes the anchoring clip to deform and shrink inward to clamp. The two anchoring steel sleeves are connected by a double-ended screw.

[0023] Furthermore, the second connecting anchor head includes an anchor ring and a wedge-shaped clamp, wherein the anchor ring is disposed at the end of the tensioning jack and has a wedge-shaped hole inside for accommodating the wedge-shaped clamp;

[0024] The wedge-shaped clamp is positioned on the steel strand at the location of the anchor ring, and the wedge-shaped clamp is threadedly connected to the wedge-shaped hole, thereby tightening the wedge-shaped clamp between the anchor ring and the steel strand.

[0025] The present invention also provides a large-span prestressed pier cap, comprising:

[0026] Prestressed steel strands are arranged longitudinally inside the pier cap, and several groups of prestressed steel strands are arranged transversely along the pier cap.

[0027] The prestressed steel strands are prestressed using a prestressed steel bar detection device installed inside the pier as described above.

[0028] The prestressed steel strand includes a plurality of first steel bars distributed in a vertical direction and a plurality of second steel bars distributed in a horizontal direction. Both the first steel bars and the second steel bars include a central section and two side sections symmetrically arranged on both sides of the central section. The central section is horizontally arranged, while the side sections on both sides are inclined. The steel bars of the side sections in the same group have different inclination angles.

[0029] Furthermore, the foundation also includes a top surface reinforcement layer, a bottom surface reinforcement layer, an end reinforcement layer, a pad layer disposed below the bottom surface reinforcement layer, and a foundation box disposed inside the foundation;

[0030] The top reinforcement layer includes upper longitudinal main reinforcement, upper transverse main reinforcement and stirrups; the bottom reinforcement layer includes lower longitudinal main reinforcement, lower transverse main reinforcement, stirrups, bottom transverse crack-resistant reinforcement and bottom longitudinal crack-resistant reinforcement; the end reinforcement layer includes end vertical structural reinforcement and end transverse structural reinforcement.

[0031] The foundation box is provided with two sets of longitudinal reinforcement and two sets of transverse reinforcement. The foundation box includes transverse structural reinforcement, longitudinal structural reinforcement, diagonal structural reinforcement and vertical structural reinforcement.

[0032] The beneficial effects of this invention are as follows: By setting the reversing component, the horizontal section of the steel strand is made collinear with the axis of the tensioning jack, eliminating the need to tilt the jack to be collinear with the steel strand, thus greatly reducing the required working space and enabling tensioning operations in areas with dense reinforcement at multiple angles. When dealing with reinforcements at different inclination angles, only the position of the guide wheel needs to be adjusted, eliminating the need for frequent adjustments to the reaction frame, which not only improves the project progress but also reduces potential errors caused by adjusting the reaction frame. In addition, the use of pressure sensors and displacement sensors, along with data acquisition and processing through a data acquisition system, enables real-time and accurate acquisition of prestress detection data, improving detection accuracy and reliability. Attached Figure Description

[0033] 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 only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A schematic diagram of a prestressed steel reinforcement detection device installed inside the foundation;

[0035] Figure 2 A schematic diagram of the cross-sectional structure for installing a prestressed steel reinforcement detection device within the foundation;

[0036] Figure 3 for Figure 2 Enlarged view of a portion at point A;

[0037] Figure 4 This is a schematic diagram showing the installation positions of the first and second laser rangefinders.

[0038] Figure 5 A schematic diagram of the connection between the two ends of a steel strand;

[0039] Figure 6 This is a schematic diagram of the reaction frame structure;

[0040] Figure 7 This is a schematic diagram showing the installation location of the third laser rangefinder;

[0041] Figure 8 This is a schematic diagram of the cross-sectional structure of the first connecting anchor head;

[0042] Figure 9 This is a schematic diagram of the cross-sectional structure of the second connecting anchor head;

[0043] Figure 10 This is a schematic diagram showing the arrangement of reinforcing bars within the pile cap;

[0044] Figure 11 for Figure 10 Sectional view of section AA;

[0045] Figure 12 This is a schematic diagram and some enlarged views of the layout of ordinary steel bars in the pile cap;

[0046] Figure 13 This is a schematic diagram and a partial enlarged view of the reinforcement layout in the foundation box.

[0047] Reference numerals: 1. Reaction frame; 11. Outer frame; 111. Positioning edge; 12. Partition plate; 2. Pressure sensor; 3. Tensioning jack; 4. Displacement sensor; 5. Reversing assembly; 51. Support base; 52. Guide wheel; 53. Steel strand; 54. Lifting assembly; 541. Lifting frame; 542. Drive component; 543. First laser rangefinder; 544. Second laser rangefinder; 55. Slide table; 551. First slide rail group; 552. Second slide rail group; 6. First connecting anchor head; 61. First anchoring clamp; 611. Anchoring clip; 612. Anchoring steel sleeve; 612a. Threaded section; 612b. Necked section; 62. Second anchoring clamp; 63. Double... 7. First connecting anchor; 71. Anchor ring; 72. Wedge-shaped clamp; 8. Third laser rangefinder; 10. Prestressed steel strand; 101. First reinforcing bar; 102. Second reinforcing bar; 20. Upper longitudinal main reinforcing bar; 30. Upper transverse main reinforcing bar; 40. Stirrup; 50. Lower longitudinal main reinforcing bar; 60. Lower transverse main reinforcing bar; 70. Bottom transverse anti-crack reinforcing bar; 80. Bottom longitudinal anti-crack reinforcing bar; 90. End vertical structural reinforcing bar; 100. End transverse structural reinforcing bar; 110. Foundation box; 111. Box transverse structural reinforcing bar; 112. Box longitudinal structural reinforcing bar; 113. Box diagonal structural reinforcing bar; 114. Box vertical structural reinforcing bar. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0049] like Figures 1 to 9 The pier shown is equipped with a prestressed steel reinforcement detection device and a large-span prestressed pier, including: reaction frame 1, pressure sensor 2, tensioning jack 3, displacement sensor 4 and data acquisition system;

[0050] The reaction frame 1, pressure sensor 2, and tensioning jack 3 are arranged in sequence in the direction away from the bearing platform. Pressure sensor 2 is used to measure the pressure generated during the tensioning process. Displacement sensor 4 is installed at the exposed part of the cylinder of tensioning jack 3 and is used to measure the displacement of tensioning jack 3 during the tensioning process. The data acquisition system is electrically connected to pressure sensor 2 and displacement sensor 4 to obtain pressure and displacement values.

[0051] The reaction frame 1 is equipped with a reversing component 5, which includes a support base 51, a guide wheel 52 and a steel strand 53. The guide wheel 52 and the tensioning jack 3 are respectively fixed at both ends of the support base 51.

[0052] One end of the steel strand 53 is connected to the reinforcing bar through the first connecting anchor head 6, forming an inclined section that is collinear with the reinforcing bar. The other end of the steel strand 53 is wrapped around the guide wheel 52 to form a horizontal section that is collinear with the axis of the tensioning jack 3, and passes through the reaction frame 1 and the pressure sensor 2 in sequence, and is connected to the tensioning jack 3 through the second connecting anchor head 7.

[0053] In this invention, the support base 51 includes a first mounting part and a second mounting part. The guide wheel 52 is disposed in the first mounting part, and the tensioning jack 3 is disposed in the second mounting part. During the pre-installation process, the guide wheel 52 is installed on the first mounting part of the support base 51 to ensure that the guide wheel 52 can rotate freely. Then, the tensioning jack 3 is installed on the second mounting part of the support base 51 to ensure that its connection with the support base 51 is firm and reliable, and its position is adjusted so that its axis is tangent to the top of the guide wheel 52.

[0054] During on-site installation, the reaction frame 1 is first installed on the exposed end face of the reinforcing steel on the foundation, ensuring a tight fit between the reaction frame 1 and the foundation surface to provide sufficient reaction support. Then, one end of the steel strand 53 is connected to the reinforcing steel via the first connecting anchor 6, and the other end is connected to the jack via the second connecting anchor 7. The guide wheel 52 converts the inclined force of the reinforcing steel into a horizontal force, creating an inclined section of the steel strand 53 collinear with the reinforcing steel and a horizontal section collinear with the axis of the tensioning jack 3. The tensioning jack 3 is then activated to tension the reinforcing steel. The pressure sensor 2 measures the pressure generated during tensioning in real time and transmits the data to the data acquisition system. The displacement sensor 4 measures the displacement of the jack during tensioning in real time and transmits the data to the data acquisition system. The data acquisition system processes and analyzes the collected pressure and displacement values, plotting a tension-displacement curve. When a turning point is observed in the tension-displacement curve with a significantly reduced slope, the force value at the turning point is the detected prestress value.

[0055] In this invention, the reversing component 5 ensures that the horizontal section of the steel strand 53 is collinear with the axis of the tensioning jack 3, eliminating the need to tilt the jack to align it with the steel strand 53. This significantly reduces the required working space and allows for tensioning operations in areas with dense reinforcement at multiple angles. Furthermore, when dealing with reinforcement at different inclination angles, only the position of the guide wheel 52 needs adjustment, eliminating the need for frequent adjustments to the reaction frame 1. This not only improves project progress but also reduces potential errors caused by adjusting the reaction frame 1. Additionally, the use of pressure sensors 2 and displacement sensors 4, along with data acquisition and processing through a data acquisition system, enables real-time and accurate acquisition of prestress detection data, improving detection accuracy and reliability.

[0056] This invention integrates the guide wheel 52 and the tensioning jack 3 onto the support base 51, reducing on-site installation time and making the installation of the entire device simpler and faster. During the pre-installation of the guide wheel 52 and the tensioning jack 3, a level or other measuring tool is used to ensure that the axis of the tensioning jack 3 is always tangent to the top of the guide wheel 52, thereby reducing errors caused by separate installation.

[0057] The reaction frame 1 includes an outer frame 11 and multiple partitions 12 disposed inside the outer frame 11. Specifically, the outer frame 11 includes two opposing vertical plates and two horizontal plates, with the vertical plates perpendicular to the horizontal plates and connected by a wedge structure. The partitions 12 are detachably disposed on the outer frame 11. The partitions 12 form a space with the side wall of the outer frame 11 to accommodate the reinforcing bars, making it more stable when subjected to tensile force, enhancing the overall structural stability of the reaction frame 1, and reducing deformation. By adjusting the position and number of the partitions 12, different numbers and positions of reinforcing bars can be flexibly accommodated, improving the versatility and adaptability of the device.

[0058] The outer edge of the end face of the outer frame 11 that contacts the bearing platform extends towards the bearing platform, forming a positioning edge 111 that wraps around the outside of the bearing platform in a circumferential direction. The positioning edge 111 increases the contact area between the reaction frame 1 and the bearing platform, ensuring that the reaction frame 1 fits tightly against the bearing platform, making the reaction frame 1 more stable during tensioning, reducing the risk of slippage or displacement, and thus improving the accuracy of prestress detection.

[0059] In a preferred embodiment of the present invention, the reversing component 5 further includes a lifting component 54 that supports and drives the support base 51 to move in the vertical direction. The lifting component 54 drives the support base 51 to rise and fall, indirectly adjusting the height of the guide wheel 52 so that it matches the steel bars with different inclination angles.

[0060] The height of the guide wheel 52 can be flexibly adjusted via the lifting assembly 54 to accommodate rebars with different inclination angles, eliminating the need for frequent adjustments to the position of the reaction frame 1 or other components. This design allows for rapid adaptation to changes in rebar inclination angles under different working conditions, improving the versatility and adaptability of the device and reducing potential errors and time costs associated with adjusting the attitude of the reaction frame 1.

[0061] In a preferred embodiment, the lifting assembly 54 specifically includes a lifting frame 541, a drive unit 542, a first laser rangefinder 543, a second laser rangefinder 544, and a control unit. The first laser rangefinder 543 is installed on the contact surface between the support platform and the reaction frame 1, and is set corresponding to the reinforcing bar to be measured, for obtaining the initial inclination angle of the reinforcing bar to be measured. The second laser rangefinder 544 is installed on the inner top wall of the reaction frame 1, for obtaining the real-time angle of the inclined section steel strand 53. The control unit receives feedback data from the first laser rangefinder 543 and the second laser rangefinder 544, and controls the drive unit 542 to adjust the height of the lifting frame 541 so that the inclined section steel strand 53 and the reinforcing bar remain collinear.

[0062] In actual implementation, firstly, the laser rangefinder accurately obtains the initial position and angle of the reinforcing bar by emitting a laser beam and measuring the time difference of the reflected light, determining the angle between the reinforcing bar and the horizontal plane, and completing the initial measurement of the reinforcing bar to provide reference data for subsequent adjustments. Secondly, the tilt sensor is installed on the steel strand 53 to measure the angle change of the steel strand 53 in real time and continuously feeds back real-time angle data to the control unit. Finally, based on the feedback data from the tilt sensor and the laser rangefinder, the control unit calculates the height that the lifting frame 541 needs to be adjusted, and sends a control command to the drive unit 542 to drive the lifting frame 541 to rise and fall, so that the steel strand 53 in the inclined section is collinear with the reinforcing bar, ensuring that the guide wheel 52 and the extension line of the reinforcing bar always remain tangent.

[0063] Through real-time feedback from tilt sensors and laser rangefinders, combined with intelligent control of the control unit, the height of the lifting frame 541 is automatically adjusted, reducing manual intervention and enabling it to quickly adapt to steel bars with different tilt angles, thus improving the accuracy and efficiency of adjustment. The combined use of tilt sensors and laser rangefinders ensures that the guide wheel 52 remains tangent to the extension line of the steel bar, improving the accuracy and reliability of the measurement.

[0064] Based on the above scheme, the bottom of the lifting assembly 54 is provided with a slide table 55; the slide table 55 includes a first slide rail group 551 and a second slide rail group 552 arranged perpendicular to the first slide rail group 551. Both the first slide rail group 551 and the second slide rail group 552 are arranged horizontally. The first slide rail group 551 is arranged parallel to the axis of the tensioning jack 3. When performing prestress testing, the lifting assembly 54 moves freely in both directions along the second slide rail group 552 and the first slide rail group 551, so that the support seat 51 abuts against the reaction frame 1. Under the tensioning action of the tensioning jack 3 on the steel strand, the middle position of the steel strand acts on the guide wheel 52, which will cause the guide wheel 52 to actively move to the vertical plane of the steel bar to be tested. The lifting assembly 54 raises and lowers the support seat 51, further controlling the height of the guide wheel 52, thereby ensuring that the extension line of the steel bar is tangent to the guide wheel 52.

[0065] In this invention, two third laser rangefinders 8 are installed on both sides of the support base 51 at one end of the guide wheel 52 for centering and calibrating the horizontal section of the steel strand 53. The two laser rangefinders are located on both sides of the steel strand 53, within the horizontal plane of the horizontal section of the steel strand 53, and the intersection of their laser beams is located on the extended line of the axis of the tension jack 3. During the installation of the guide wheel 52 and the tension jack 3 with the support base 51, the two third laser rangefinders 8 measure the distance between the two sides of the steel strand 53. By comparing these two distance values, it can be accurately determined whether the steel strand 53 is located on the extended line of the axis of the tension jack 3, thus achieving centering and calibrating the horizontal section of the steel strand 53, so that the guide wheel 52 is installed in a centered position relative to the axis of the tension jack 3.

[0066] Real-time feedback from two laser rangefinders allows for rapid detection of any deviation in the steel strand 53, enabling timely calibration to ensure it remains centered. This ensures accurate positioning of the steel strand 53 in the horizontal section, improving the overall measurement accuracy of the detection system.

[0067] In this scheme, the first connecting anchor head 6 includes a first anchoring clamp 61 connected to the steel strand 53 and a second anchoring clamp connected to the reinforcing bar; both the first anchoring clamp 61 and the second anchoring clamp include an anchoring clip 611 and an anchoring steel sleeve 612 sleeved on the outside of the anchoring clip 611. The anchoring steel sleeve 612 has a threaded section 612a and a necking section 612b inside. The necking section 612b causes the anchoring clip 611 to deform and shrink inward to clamp, and the two anchoring steel sleeves 612 are connected by a double-ended screw 63.

[0068] The two anchoring sleeves 612 are connected by a double-ended screw 63, allowing the distance between the two anchoring clamps to be adjusted as needed. This adjustability enables the structure to accommodate steel strands 53 and reinforcing bars of different lengths. In addition, the threaded section 612a can apply a preload to the anchoring clamp 611 by tightening the double-ended screw 63, enhancing the clamping effect.

[0069] In this scheme, the second connecting anchor head 7 includes an anchor ring 71 and a wedge-shaped clamp 72. The anchor ring 71 is located at the end of the tensioning jack 3 and has a wedge-shaped hole inside to accommodate the wedge-shaped clamp 72. The wedge-shaped clamp 72 is located at the position of the steel strand 53 where the anchor ring 71 is located, and the wedge-shaped clamp 72 is threadedly connected to the wedge-shaped hole, so that the wedge-shaped clamp 72 is tightened between the anchor ring 71 and the steel strand 53.

[0070] Tension is applied to the steel strand 53 or the reinforcing bar using a jack. As the tension increases, the clamping plates are further wedged in the conical hole, generating a strong clamping force that firmly clamps the steel strand 53 or the reinforcing bar.

[0071] like Figure 10-13 As shown, the present invention also provides a large-span prestressed pier, comprising: prestressed steel strands 10 arranged longitudinally within the pier, and several groups of prestressed steel strands 10 arranged transversely within the pier; the prestressed steel strands 10 are subjected to prestress testing using a prestressed steel reinforcement testing device installed within the pier.

[0072] The prestressed steel strand 10 includes a plurality of first steel bars 101 distributed in the vertical direction and a plurality of second steel bars 102 distributed in the horizontal direction. The first steel bars 101 and the second steel bars 102 each include a middle section and two side sections symmetrically arranged on both sides of the middle section. The middle section is horizontally arranged, while the side sections on both sides are inclined. The steel bars of the side sections in the same group have different inclination angles.

[0073] The foundation is equipped with prestressed steel strands 10 to effectively increase the foundation span, thereby enhancing its ability to span underground structures such as subways, utility tunnels, and underground pipelines, and reducing investment in relocation and renovation of underground structures. Furthermore, the use of a prestressed steel reinforcement testing device allows for real-time monitoring of prestress application, ensuring that the magnitude and distribution of prestress meet design requirements and guaranteeing construction quality. The prestressed steel strands 10 installed inside the foundation are anchored at both ends of the foundation after tensioning. After tensioning and anchoring, anti-corrosion coating is sprayed onto the anchoring areas at both ends of the foundation to improve structural durability.

[0074] As a preferred structure of the above scheme, the pier also includes a top surface reinforcement layer, a bottom surface reinforcement layer, an end reinforcement layer, a pad layer disposed below the bottom surface reinforcement layer, and a pier box chamber 110 disposed inside the pier.

[0075] The top reinforcement layer includes upper longitudinal main reinforcement 20, upper transverse main reinforcement 30 and stirrups 40; the bottom reinforcement layer includes lower longitudinal main reinforcement 50, lower transverse main reinforcement 60, stirrups 40, bottom transverse crack-resistant reinforcement 70 and bottom longitudinal crack-resistant reinforcement 80; the end reinforcement layer includes end vertical structural reinforcement 90 and end transverse structural reinforcement 100.

[0076] The foundation box 110 is provided with two sets of longitudinal reinforcement and two sets of transverse reinforcement. The foundation box 110 includes transverse structural reinforcement 111, longitudinal structural reinforcement 112, diagonal structural reinforcement 113, and vertical structural reinforcement 114.

[0077] The longitudinal main reinforcement, shear stirrups, and transverse tensile reinforcement within the pile cap enhance its longitudinal bending capacity, transverse bending capacity, and shear capacity. The standard section of the pile cap features a single-box, double-cell hollow cross-section to reduce its self-weight. A rectangular solid cross-section is used at the top of the pile foundation and at the bottom of the pier to improve load transfer capacity. The pile cap's interior incorporates ordinary steel reinforcement in the top, bottom, and end reinforcement layers, as well as in the 110mm diameter of the pile cap chambers, enhancing its load-bearing capacity and crack resistance. A concrete cushion layer is placed beneath the pile cap, with a soil bearing capacity of not less than 150kPa.

[0078] The present invention follows the construction sequence of pile foundation construction, pile cap pouring, first steel bar tensioning 101, bridge pier construction, superstructure construction, second steel bar tensioning 102, and anti-corrosion coating spraying in the anchor sealing area to ensure the ease of construction and applicability of the pile cap.

[0079] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A prestressed steel reinforcement detection device installed inside a foundation, characterized in that, This includes a reaction frame, pressure sensor, tension jack, displacement sensor, and data acquisition system; The reaction frame, pressure sensor, and tensioning jack are arranged sequentially away from the bearing platform. The pressure sensor is used to measure the pressure generated during the tensioning process. The displacement sensor is installed at the exposed part of the hydraulic cylinder of the tensioning jack and is used to measure the displacement of the tensioning jack during the tensioning process. The data acquisition system is electrically connected to the pressure sensor and the displacement sensor to acquire the pressure value and the displacement value. The reaction frame is equipped with a reversing component, which includes a support base, a guide wheel, and a steel strand. The guide wheel and the tensioning jack are respectively fixed at both ends of the support base. One end of the steel strand is connected to the reinforcing bar through the first connecting anchor head to form an inclined section that is collinear with the reinforcing bar. The other end of the steel strand is wrapped around the guide wheel to form a horizontal section that is collinear with the axis of the tensioning jack. The horizontal section passes through the reaction frame and the pressure sensor in sequence and is connected to the tensioning jack through the second connecting anchor head.

2. The prestressed steel reinforcement detection device installed inside the pier cap according to claim 1, characterized in that, The reaction frame includes an outer frame and a plurality of partitions disposed inside the outer frame; The outer edge of the end face of the outer frame that contacts the bearing platform extends toward the bearing platform, forming a positioning edge that circumferentially covers the outside of the bearing platform.

3. The prestressed steel reinforcement detection device installed inside the pier cap according to claim 1, characterized in that, The reversing assembly also includes a lifting assembly that supports and drives the support base to move in the vertical direction; The lifting assembly drives the support base to adjust the height of the guide wheel.

4. The prestressed steel reinforcement detection device installed inside the pier cap according to claim 3, characterized in that, The lifting assembly includes a lifting frame, a drive unit, a first laser rangefinder, a second laser rangefinder, and a control unit; The first laser rangefinder is installed on the contact surface between the pier and the reaction frame, and is set corresponding to the steel bar to be measured, in order to obtain the initial inclination angle of the steel bar to be measured; The second laser rangefinder is installed on the inner top wall of the reaction frame to obtain the real-time angle of the inclined section of the steel strand; The control unit receives feedback data from the first laser rangefinder and the second laser rangefinder, and controls the drive component to adjust the height of the lifting frame so that the inclined section of steel strand and the reinforcing bar remain collinear.

5. The prestressed steel reinforcement detection device installed inside the pier cap according to claim 3, characterized in that, The bottom of the lifting assembly is provided with a sliding table; The slide table includes a first slide rail group and a second slide rail group arranged perpendicular to the first slide rail group, both of which are arranged horizontally.

6. The prestressed steel reinforcement detection device installed inside the pier cap according to claim 1, characterized in that, A third laser rangefinder is installed on both sides of the support base at the end where the guide wheel is mounted, for centering and calibrating the horizontal section of the steel strand.

7. The prestressed steel reinforcement detection device installed inside the pier cap according to claim 1, characterized in that, The first connecting anchor head includes a first anchoring clamp connected to the steel strand and a second anchoring clamp connected to the reinforcing bar; Both the first anchoring clamp and the second anchoring clamp include an anchoring clip and an anchoring steel sleeve sleeved on the outside of the anchoring clip. The anchoring steel sleeve has a threaded section and a necking section inside. The necking section causes the anchoring clip to deform and shrink inward to clamp. The two anchoring steel sleeves are connected by a double-ended screw.

8. The prestressed steel reinforcement detection device installed inside the pier cap according to claim 1, characterized in that, The second connecting anchor head includes an anchor ring and a wedge-shaped clamp. The anchor ring is located at the end of the tensioning jack and has a wedge-shaped hole inside to accommodate the wedge-shaped clamp. The wedge-shaped clamp is positioned on the steel strand at the location of the anchor ring, and the wedge-shaped clamp is threadedly connected to the wedge-shaped hole, thereby tightening the wedge-shaped clamp between the anchor ring and the steel strand.

9. A large-span prestressed pier cap, characterized in that, include: Prestressed steel strands are arranged longitudinally inside the pier cap, and several groups of prestressed steel strands are arranged transversely along the pier cap. The prestressed steel strands are prestressed using the prestressed steel bar prestressing detection device inside the pier as described in claim 1. The prestressed steel strand includes a plurality of first steel bars distributed in a vertical direction and a plurality of second steel bars distributed in a horizontal direction. Both the first steel bars and the second steel bars include a central section and two side sections symmetrically arranged on both sides of the central section. The central section is horizontally arranged, while the side sections on both sides are inclined. The steel bars of the side sections in the same group have different inclination angles.

10. The large-span prestressed pier cap according to claim 9, characterized in that, The foundation also includes a top reinforcement layer, a bottom reinforcement layer, an end reinforcement layer, a pad layer disposed below the bottom reinforcement layer, and a foundation box disposed inside the foundation. The top reinforcement layer includes upper longitudinal main reinforcement, upper transverse main reinforcement and stirrups; the bottom reinforcement layer includes lower longitudinal main reinforcement, lower transverse main reinforcement, stirrups, bottom transverse crack-resistant reinforcement and bottom longitudinal crack-resistant reinforcement; the end reinforcement layer includes end vertical structural reinforcement and end transverse structural reinforcement. The foundation box is provided with two sets of longitudinal reinforcement and two sets of transverse reinforcement. The foundation box includes transverse structural reinforcement, longitudinal structural reinforcement, diagonal structural reinforcement and vertical structural reinforcement.

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