Composite loading device and loading method for correcting attitude of i-shaped beam

Abstract

The present application belongs to the technical field of bridge structure test loading device, and discloses a composite loading device and loading method capable of correcting the attitude of I-beam, which comprises a plurality of out-of-plane loading devices arranged uniformly along the axial direction of the I-beam test piece and a longitudinal loading device at the center of the top surface of the I-beam test piece; the out-of-plane loading device comprises bidirectional jacks on both sides of the web of the I-beam test piece, which are respectively inner pulling jacks and outer pushing jacks, and the end of the jack is connected with the upper flange plate or the lower flange plate of the I-beam test piece; the force applied by the inner pulling jacks and the outer pushing jacks is equal in size but opposite in direction; the axial spacing L of the jack is consistent with the transverse spacing T; one end of the I-beam test piece is erected on a fixed hinge support, and the other end is erected on a sliding hinge support; a regulating platform is arranged between the hinge support and the I-beam test piece; and the axis of the regulating platform is parallel to the axis of the I-beam test piece. The present application can realize composite loading in the transverse and longitudinal directions, correct the transverse attitude of the beam body, and truly simulate the stress working condition of the beam body.

Description

Technical Field

[0001] This invention belongs to the technical field of bridge structure test loading devices, specifically relating to a composite loading device and loading method that can correct the posture of an I-beam. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Concrete thin-web beams are widely used in bridge engineering due to their excellent mechanical properties and structural efficiency, such as concrete box girders and I-beams. In actual working conditions, these beams exhibit typical spatial stress characteristics. For example, the web, as a key force-transmitting component, not only bears the overall bending and shear effects along the bridge's longitudinal direction, but also experiences significant additional out-of-plane bending moments from loads such as vehicle wheel loads on the bridge deck and temperature differences between the inside and outside of the box girder. These additional out-of-plane bending moments generate gradient-distributed vertical normal stresses along the thickness direction of the web, which in turn disturb the principal stress states on the inner and outer sides of the web, affecting the overall structural safety.

[0004] Existing technology discloses a loading device for testing the web distortion fatigue of an I-beam main beam, including a base, a test beam mounted on the base, X-shaped or K-shaped cross braces on the sides of the test beam, a transmission component mounted on the free end of the X-shaped or K-shaped cross braces, and a servo hydraulic actuator mounted on the transmission component. The servo hydraulic actuator applies out-of-plane force to the vertical stiffening ribs and horizontal node plates of the test beam through the transmission component and the X-shaped or K-shaped cross braces, simulating the distortion fatigue effect generated at the web gap of the I-beam main beam due to different deflection differences under vehicle eccentric loading.

[0005] The above solution has the following drawbacks:

[0006] The test only applies horizontal out-of-plane action to a specific area of ​​the specimen (web gap), which cannot apply uniform transverse out-of-plane bending moment to the web of the I-beam, and cannot achieve the composite loading of transverse out-of-plane bending moment and longitudinal in-plane bending and shear. It is difficult to truly simulate the composite stress condition of the beam under multi-source load, which makes it impossible for testers to make correct judgments on the performance and safety of the test component.

[0007] In addition, the above scheme directly fixes the I-beam to the base without considering the bending deformation that may occur in the length or width direction of the I-beam during actual loading. This excessive constraint will interfere with the internal force balance of the I-beam specimen, resulting in inaccurate test data. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a composite loading device and loading method that can correct the posture of an I-beam, which can solve the technical problems of the prior art that it is impossible to apply a uniform out-of-plane bending moment in the transverse direction to the web of the I-beam specimen, impossible to achieve composite loading of out-of-plane bending moment in the transverse direction and in-plane bending and shear in the longitudinal direction, and excessive constraints leading to inaccurate test data.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] In the first aspect, a composite loading device that can correct the posture of an I-beam is provided, including a number of out-of-plane loading devices uniformly arranged along the axial direction of the I-beam specimen and a longitudinal loading device at the center of the top surface of the I-beam specimen.

[0011] The out-of-plane loading device includes bidirectional jacks on both sides of the web of the I-beam specimen, namely an internal tension jack and an external push jack. The top of the jacks is connected to the upper or lower flange of the I-beam specimen. The internal tension jack and the external push jack apply forces of equal magnitude but opposite direction. The axial spacing L of the jacks is consistent with the transverse spacing T.

[0012] The longitudinal loading device includes a loading ball seat at the center of the top surface of the I-beam specimen, and the top surface of the loading ball seat is connected to an actuator perpendicular to the I-beam specimen;

[0013] One end of the I-beam specimen is mounted on a fixed hinge support, and the other end is mounted on a sliding hinge support; an adjustment platform is set between the hinge support and the I-beam specimen; and the axis of the adjustment platform is parallel to the axis of the I-beam specimen.

[0014] Preferably, the adjustment platform includes a slidingly connected arc-shaped base and a swing table. The bottom surface of the swing table is provided with an arc-shaped groove, and the top surface of the arc-shaped groove is provided with a worm gear groove. A worm gear meshing with the worm gear groove is rotatably connected inside the arc-shaped base. A stepper motor is installed on the side of the arc-shaped base, and the output shaft of the stepper motor is fixedly connected to the worm gear.

[0015] Preferably, inclinometers are installed on both the upper and lower flange plates; a PLC controller is also installed on the arc-shaped base, the inclinometers are connected to the communication interface of the PLC controller, and the PLC controller is electrically connected to the stepper motor.

[0016] Preferably, both the fixed hinge support and the sliding hinge support include a base, on which a roller is placed, and a top plate is fixedly connected to the roller; the fixed hinge support has limiting strips fixedly connected to the base on both sides of the roller, while the sliding hinge support does not have limiting strips on both sides of the roller; the adjustment platform is fixedly connected to the top plate, and buffer airbags are provided on both sides of the adjustment platform.

[0017] Preferably, a temporary support rod is provided on the axial side of the fixed hinge support or the sliding hinge support. The top end of the temporary support rod is bolted to the top plate and the bottom end is bolted to the base to restrict the rotation of the fixed hinge support or the sliding hinge support.

[0018] Preferably, the upper flange plate and the lower flange plate are provided with corresponding reserved holes at their edges. The two ends of the inner pull jack are fixedly connected to the lugs, and the two ends of the outer push jack are fixedly connected to the universal ball plate. The lugs or universal ball plate are connected to the reserved holes through the inner pull connector or end plate.

[0019] Preferably, the inner pull connector includes a U-shaped fork and a pin. The U-shaped fork has a pin hole that matches the earring. After the earring is inserted into the U-shaped fork and aligned, the pin is inserted. A first threaded hole is opened at the end of the U-shaped fork away from the earring. The first threaded hole is threadedly connected to the flange bolt in the reserved hole.

[0020] Preferably, multiple second threaded holes are evenly opened on the edges of the universal ball plate and the end plate, and the second threaded holes are threadedly connected to the fixing bolts; a circular through hole and a hexagonal cavity are opened in the center of the end plate, the head of the flange bolt is left in the hexagonal cavity, and the shank of the flange bolt passes through the circular through hole, the reserved hole, and the round hole of the pad plate, and is threadedly connected to the nut on the top or bottom surface of the flange plate of the I-beam.

[0021] Secondly, a loading method for the aforementioned composite loading device capable of correcting the attitude of an I-beam is provided, the specific steps of which are as follows:

[0022] When fabricating I-beam specimens, symmetrical and equally spaced pre-drilled holes are made, and an inclinometer is installed.

[0023] A buffer airbag was placed on the hinge support and the adjustment platform was fixed. The two ends of the I-beam specimen were placed on the adjustment platform. During the installation process, the hinge support was locked by temporary struts. The inclinometer and the adjustment platform were connected. The adjustment platform was used to adjust the posture of the I-beam specimen and then locked.

[0024] Assemble the out-of-plane loading device and the longitudinal loading device in sequence; remove the temporary support rods and begin loading;

[0025] During loading, the I-beam specimen can be subjected to longitudinal in-plane bending shear and transverse out-of-plane bending moment loading simultaneously, or a single-mode loading can be performed first, followed by a composite loading.

[0026] During composite loading, the adjustment platform adaptively adjusts the lateral orientation of the I-beam specimen in real time based on the detection results of the two inclinometers; and records the loading data when diagonal cracks appear in the web and when the I-beam specimen fails.

[0027] Preferably, the longitudinal loading device uses force control in the initial stage of loading and displacement control when the I-beam specimen is close to failure; the out-of-plane loading device uses force control.

[0028] Compared with the prior art, the advantages and positive effects of this invention are:

[0029] The composite loading device for correcting the posture of an I-beam of the present invention can apply a uniform transverse bending moment to the web of the I-beam specimen, apply a vertical force to the I-beam specimen using an actuator to perform longitudinal in-plane bending and shear loading, and apply a transverse out-of-plane bending moment to the web of the I-beam specimen using an out-of-plane loading device. There is no mutual interference between the two loading modes, and they can work normally at the same time. It can realistically simulate the composite stress condition of the beam, which makes it easier for test personnel to make correct judgments on the performance and safety of the test component.

[0030] Furthermore, this invention places the I-beam specimen on a hinged support, providing the I-beam specimen with rotational freedom for longitudinal bending to accommodate the longitudinal bending deformation requirements of the I-beam specimen under loading. The adjustment platform corrects the lateral posture of the beam during the installation and compound loading process of the I-beam specimen, eliminating lateral offset of the loading ball and avoiding additional torque interference to the test results caused by vertical force offset. The hinged support and adjustment platform work independently, simultaneously meeting the deformation constraint requirements of longitudinal in-plane bending shear and transverse out-of-plane bending moment loading on the beam ends, thus improving the reliability of the test results. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0032] Figure 1 This is a front view of a composite loading device capable of correcting the posture of an I-beam according to Embodiment 1 or Embodiment 2 of the present invention;

[0033] Figure 2 This is a rear view of a composite loading device capable of correcting the posture of an I-beam according to Embodiment 1 or Embodiment 2 of the present invention;

[0034] Figure 3 This is a top view of a composite loading device capable of correcting the posture of an I-beam according to Embodiment 1 or Embodiment 2 of the present invention;

[0035] Figure 4 This is from Embodiment 1 or Embodiment 2 of the present invention. Figure 1 Sectional view of section AA;

[0036] Figure 5 This is from Embodiment 1 or Embodiment 2 of the present invention. Figure 1 Sectional view of section BB;

[0037] Figure 6 This is Embodiment 1 or Embodiment 2 of the present invention. Figure 1 A sectional view of section C-C;

[0038] Figure 7 This is a three-dimensional diagram of the adjustment platform of Embodiment 1 or Embodiment 2 of the present invention;

[0039] Figure 8 This is a side view of the adjustment platform according to Embodiment 1 or Embodiment 2 of the present invention;

[0040] Figure 9 This is a cross-sectional view of the adjustment platform along the worm gear axis of Embodiment 1 or Embodiment 2 of the present invention;

[0041] Figure 10 This is a schematic diagram of the meshing of the worm gear groove and the worm in Embodiment 1 or Embodiment 2 of the present invention;

[0042] Figure 11 This is a front view of the inner pull connector of Embodiment 1 or Embodiment 2 of the present invention;

[0043] Figure 12 This is a side view of the inner pull connector of Embodiment 1 or Embodiment 2 of the present invention;

[0044] Figure 13 This is a top view of the end plate of Embodiment 1 or Embodiment 2 of the present invention;

[0045] Figure 14 This is a side view of the end plate of Embodiment 1 or Embodiment 2 of the present invention;

[0046] Figure 15 This is a side view of the transverse bending deformation of the I-beam specimen of Embodiment 1 or Embodiment 2 of the present invention;

[0047] Figure 16 This is a side view of the lateral posture adjustment of the I-beam specimen in Embodiment 1 or Embodiment 2 of the present invention;

[0048] In the picture:

[0049] 1. I-beam specimen; 2. Fixed hinge support; 21. Roller; 22. Limiting strip; 23. Temporary support; 3. Sliding hinge support; 4. Adjustment platform; 41. Swinging table; 42. Arc-shaped base; 43. Stepper motor; 44. Communication interface; 45. Slider guide rail; 46. Worm gear groove; 47. Worm; 5. Support pad; 6. Loading ball seat; 7. Internal pull jack; 71. Earring; 8. External pusher 81. Jack; 9. Universal ball joint; 10. Internal pull connector; 11. U-shaped fork; 12. First threaded hole; 13. Pin hole; 14. Pin; 15. End plate; 16. Circular through hole; 17. Hexagonal cavity; 18. Second threaded hole; 19. Reserved hole; 10. Flange bolt; 11. Nut; 12. Washer plate; 13. Buffer airbag; 14. First inclinometer; 15. Second inclinometer. Detailed Implementation

[0050] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0051] The present invention will now be described in detail with reference to the accompanying drawings.

[0052] Example 1

[0053] This embodiment discloses a composite loading device capable of correcting the attitude of an I-beam, such as... Figure 1 , Figure 2 , Figure 3 As shown, it includes several out-of-plane loading devices uniformly arranged along the axial direction of the I-beam specimen 1, and a longitudinal loading device at the center of the top surface of the I-beam specimen 1. Figure 1 , Figure 2 , Figure 4 As shown, the longitudinal loading device includes a loading ball seat 6 at the center of the top surface of the I-beam specimen 1. An actuator is connected to the top surface of the loading ball seat 6. The actuator cooperates with the reaction frame (not shown in the figure). The actuator applies a vertical force Fn to the I-beam specimen 1 perpendicular to the I-beam specimen 1, forming a longitudinal in-plane bending-shear loading mode.

[0054] like Figure 1 , Figure 2 , Figure 4 As shown, the out-of-plane loading device includes bidirectional jacks installed on both sides of the web of the I-beam specimen 1, namely an inward-pulling jack 7 and an outward-pushing jack 8. The two ends of each jack are connected to the upper and lower flange plates of the I-beam specimen 1, respectively. The inward-pulling jack 7 causes the upper and lower flange plates to contract inwards, applying an inward pulling force to the flange of the I-beam specimen 1. The outward-pushing jack 8 causes the upper and lower flange plates to tension outwards, applying an outward pushing force to the flange of the I-beam specimen 1. It should be noted that the forces applied by the inward-pulling jack 7 and the outward-pushing jack 8 are equal in magnitude. In this embodiment, by simultaneously applying inward pulling and outward pushing forces to both sides of the I-beam specimen 1, forces of equal magnitude and opposite direction are generated, achieving vertical internal force self-balancing and generating only lateral out-of-plane bending moments, thus eliminating interference with longitudinal loading.

[0055] In this embodiment, as Figure 3As shown, the axial spacing L of the jacks is consistent with the transverse spacing T. The axial spacing L refers to the axial direction along the I-beam specimen 1, and the transverse spacing T refers to the width direction along the I-beam specimen 1. This arrangement ensures that the loading force applied by the jacks is evenly applied to the flange plate of the I-beam specimen 1 and diffuses along a 45° angle to the web plate of the I-beam specimen 1, thereby generating a uniform transverse out-of-plane bending moment and forming a transverse out-of-plane loading mode. It can be understood that by using both the longitudinal loading device and the out-of-plane loading device to load the I-beam specimen 1, a composite loading of transverse out-of-plane bending moment and longitudinal in-plane bending shear can be achieved.

[0056] like Figure 1 , Figure 2 As shown, both ends of the I-beam specimen 1 are mounted on hinged supports, and the axis of the hinged supports is parallel to the axis of the I-beam specimen 1. The hinged supports include a fixed hinged support 2 and a sliding hinged support 3. One end of the I-beam specimen 1 is mounted on the fixed hinged support 2, and the other end is mounted on the sliding hinged support 3.

[0057] It should be noted that the hinged support not only provides a stable support foundation for the I-beam specimen, but also allows the end of the I-beam specimen 1 to rotate axially around the roller, providing longitudinal bending rotational freedom to accommodate the longitudinal bending deformation requirements of the I-beam specimen 1 under loading, avoiding excessive constraint that would generate additional bending moment, and improving the reliability of the test results. The sliding hinged support 3 can provide axial displacement freedom to accommodate the expansion and contraction displacement caused by loading, avoiding the accumulation of axial force due to displacement restriction.

[0058] like Figure 1 , Figure 5 , Figure 6 As shown, an adjustment platform 4 is provided between the hinge support and the bottom surface of the end of the I-beam specimen 1. In this embodiment, an adjustment platform 4 is provided between the hinge support and the bottom surface of the end of the I-beam specimen 1, and the axis of the swing table 41 is parallel to the axis of the I-beam specimen 1. When the I-beam specimen 1 deflects laterally on both sides, the I-beam specimen 1 is adjusted by the adjustment platform 4.

[0059] It should be noted that the adjustment platform 4 dynamically adjusts the lateral attitude of the I-beam specimen 1 during the composite loading process, ensuring that the loading ball seat 6 and the adjustment platform 4 are always in the same vertical plane. This avoids additional torque on the I-beam specimen 1 due to vertical force offset, which could interfere with the test results. The out-of-plane loading device and the longitudinal loading device, through their structural layout, ensure both the uniformity of the lateral out-of-plane bending moment and avoid interference from lateral deformation during longitudinal loading. This realistically simulates the spatial stress behavior of the I-beam specimen (bridge) under complex working conditions, solving the problems in existing technologies such as the inability to apply a uniform lateral out-of-plane bending moment to the web of the I-beam specimen, the inability to achieve composite loading of lateral out-of-plane bending moment and longitudinal in-plane bending and shear, and the inaccurate test data caused by beam deformation interference during loading.

[0060] like Figures 7 to 9 As shown, the adjustment platform 4 includes an arc-shaped base 42 and a swing table 41 with an arc-shaped bottom surface. The swing table 41 and the arc-shaped base 42 are slidably connected by two arc-shaped slider guide rails 45 arranged parallel to each other along the axial direction. Between the two slider guide rails 45, an arc-shaped groove is provided on the bottom surface of the swing table 41, and a worm gear groove 46 is formed on the top surface of the arc-shaped groove. In this embodiment, the guide rails of the slider guide rails 45 are fixedly connected to the arc-shaped base 42, and the sliders are fixedly connected to the bottom surface of the swing table 41.

[0061] like Figure 9 As shown, a worm gear 47 is rotatably connected inside the arc-shaped base 42, and the worm gear 47 is perpendicular to the center of the axis of the arc-shaped base 42; as Figure 9 , Figure 10 As shown, the worm 47 meshes with the worm wheel groove 46 on the top surface of the arc-shaped groove. It can be understood that when the worm 47 rotates, it will drive the worm wheel groove 46 to rotate, thereby causing the swing table 41 to slide relative to the arc-shaped base 42, and thus changing the angle between the top surface of the swing table 41 and the vertical line.

[0062] like Figure 7 As shown, a stepper motor 43 is mounted on the side of the arc-shaped base 42, and the output shaft of the stepper motor 43 is fixedly connected to the worm gear 47; by controlling the forward and reverse rotation of the stepper motor 43, the position of the swing table 41 relative to the arc-shaped base 42 can be adjusted.

[0063] It is understandable that when the out-of-plane loading device applies load to the I-beam specimen 1, such as Figure 15 As shown, the I-beam specimen 1 may undergo lateral deflection when a transverse out-of-plane bending moment is applied, resulting in inconsistent inclination angles between the upper and lower flanges. This causes a shift in vertical force, generating additional torque on the I-beam specimen 1, interfering with the accuracy of in-plane bending-shear loading, and thus affecting the reliability of the test results. During the loading process, as... Figure 16 As shown, by adjusting the angle of the swing table 41, the balance of the lateral posture of the I-beam specimen 1 is maintained, so that the loading ball seat 6 and the swing table 41 are always in the vertical plane, avoiding the additional torque on the I-beam specimen 1 caused by the vertical force deviation, which would interfere with the test results.

[0064] like Figure 15 , Figure 16 As shown, a first inclinometer 16 is installed on the upper flange plate at both ends of the I-beam specimen 1, and a second inclinometer 17 is installed on the lower flange plate. The two inclinometers are used to obtain the inclination angle of the I-beam specimen 1. It should be noted that, as... Figure 7As shown, in this embodiment, a PLC controller is also installed on the arc-shaped base 42. The first inclinometer 16 and the second inclinometer 17 are connected to the communication interface 44 of the PLC controller to transmit the monitored tilt angle to the PLC controller. The PLC controller is electrically connected to the stepper motor 43 to control the stepper motor 43 to rotate forward or reverse, or to turn it off.

[0065] It should be noted that the PLC controller sets the operating conditions for stepper motor 43 as follows: stepper motor 43 is started when the sum of the first inclinometer 16 and the second inclinometer 17 is not zero. During the lateral out-of-plane bending moment loading process, the I-beam specimen 1 will undergo lateral bending deformation (e.g., Figure 15 As shown), this causes the value of the first inclinometer 16 on the upper flange to increase at an accelerated rate, which in turn triggers the adjustment platform 4 to work, correcting the lateral attitude of the I-beam specimen 1 in real time, so that the values ​​of the first inclinometer 16 and the second inclinometer 17 are equal but opposite in sign (e.g., Figure 16 (As shown).

[0066] It should be noted that in this embodiment, the top surface of the swing table 41 is fixedly connected to the support pad 5 to increase the force-bearing area with the I-beam specimen 1, and the adjustment platform 4 is fixedly connected to the hinge support.

[0067] In this implementation, the magnitude of the lateral bending moment is ;

[0068] In the formula:

[0069] F is the force applied by the jacks; L is the axial spacing of the jacks; T is the lateral spacing of the jacks; θ is the average rotation angle between the upper and lower flanges of the I-beam specimen 1 after lateral bending deformation.

[0070] like Figure 1 , Figure 2 , Figure 5 , Figure 6 As shown, both the fixed hinge support 2 and the sliding hinge support 3 include a base, on which a roller 21 is placed. A top plate is fixedly connected to the roller, and an adjustment platform is fixedly connected to the top plate. The bottom end of the I-beam specimen 1 is placed on the top plate of the adjustment platform. The roller 21 is perpendicular to the axis of the I-beam specimen 1, so that the end of the I-beam specimen 1 rotates axially around the roller 21.

[0071] In this embodiment, as Figure 1 , Figure 5 As shown, along the axial direction of the I-beam specimen 1, limiting strips 22 are placed on both sides of the roller 21 of the fixed hinge support 2. The limiting strips 22 are fixedly connected to the base (e.g., by welding), so that the roller 21 can only rotate axially between the limiting strips 22 and cannot move in the horizontal direction. Figure 1 , Figure 6As shown, the sliding hinge support 3 has no limiting strips on both sides of the roller 21, so the sliding hinge support 3 can move in the horizontal direction.

[0072] like Figure 1 , Figure 5 , Figure 6 As shown, buffer airbags 15 are provided on both sides of the adjustment platform 4 on the top surface of the fixed hinge support 2 or the sliding hinge support 3. The function of the buffer airbags 15 is to prevent the I-beam specimen 1 from rotating and overturning during installation and loading. It should be noted that, in order to avoid test interference, a set initial gap is left between the buffer airbags 15 and the bottom surface of the I-beam specimen 1 (in this embodiment, the gap is controlled at 1-3cm). When the I-beam specimen 1 undergoes a lateral rotation, the bottom surface of the I-beam specimen 1 contacts the buffer airbags 15, and the buffer airbags 15 gradually intervene to work.

[0073] It should also be noted that the buffer airbag 15 uses an air spring, which gives the buffer airbag 15 variable stiffness characteristics. That is, when it first intervenes in the work, the elastic stiffness of the buffer airbag 15 is small, and its impact on the lateral bending deformation of the I-beam specimen 1 and the normal operation of the adjustment platform 4 is small. However, when the I-beam specimen 1 experiences a large turning angle that may cause it to overturn, the buffer airbag 15 can provide greater stiffness to prevent the accident from happening.

[0074] like Figure 1 , Figure 2 , Figure 5 , Figure 6 As shown, a temporary support rod 23 is also provided on the axial side of the hinge support. The top end of the temporary support rod 23 is bolted to the top plate of the hinge support, and the bottom end of the temporary support rod 23 is bolted to the base, which can restrict the rotation of the hinge support. It should be noted that during the installation of the I-beam specimen 1, the temporary support rod 23 is installed on the axial side of the hinge support to lock the hinge support and prevent it from rotating. After the I-beam specimen 1 is installed in place and before loading, the temporary support rod 23 can be removed.

[0075] In this embodiment, the I-beam specimen 1 is a reinforced concrete structure. For example... Figure 3 As shown, the upper and lower flanges of the I-beam specimen 1 have corresponding pre-drilled holes 11 at their edges. These holes 11 are evenly distributed along the axial direction of the I-beam specimen 1 and are symmetrically distributed relative to the web of the I-beam specimen 1. The axial and lateral spacing of the pre-drilled holes 11 is consistent. In this embodiment, the pre-drilled holes can be pre-drilled by embedding circular steel pipes before concrete pouring or after pouring. The function of the pre-drilled holes 11 is to connect to a bidirectional jack and to achieve a positioning function.

[0076] In this embodiment, the two ends of the jack are hinged to the flange plates of the I-beam specimen 1. Specifically, as shown... Figure 1 , Figure 4 As shown, the top and bottom ends of the internal pull jack 7 are fixedly connected to the lugs 71, and are connected to the I-beam specimen 1 through the internal pull connector 9 and the flange bolts 12.

[0077] like Figure 11 , Figure 12 As shown, the inner pull connector 9 includes a U-shaped fork 91 and a pin 94. The U-shaped fork 91 has a pin hole 93 that matches the earring 71. After the earring 71 is inserted into the U-shaped fork 91 and aligned, the pin 94 is inserted, so that both ends of the inner pull jack 7 are hinged to the inner pull connector 9. A first threaded hole 92 is opened at the end of the U-shaped fork 91 away from the earring 71. The first threaded hole 92 is threadedly connected to the flange bolt 12 in the reserved hole 11. A washer 14 is installed between the bolt head of the flange bolt 12 and the flange plate to increase the stress-bearing area between the flange bolt 12 and the flange plate and avoid stress concentration at the bolt head of the flange bolt 12.

[0078] like Figure 4 As shown, the top and bottom ends of the outward-pushing jack 8 are fixedly connected to a universal ball joint 81, and the side of the universal ball joint 81 away from the outward-pushing jack 8 is bolted to the end plate 10. Figure 13 , Figure 14 As shown, multiple second threaded holes 103 are evenly opened on the edges of the universal ball bearing 81 and the end plate 10, and the second threaded holes are threadedly connected to the fixing bolts. A circular through hole 101 and a hexagonal cavity 102 are opened in the center of the end plate 10, wherein the hexagonal cavity 102 is set away from the flange plate, the head of the flange bolt 12 is left in the hexagonal cavity 102, and the shank of the flange bolt 12 passes through the circular through hole 101, the reserved hole 11, and the round hole of the pad, and is threadedly connected to the nut 13 on the top or bottom surface of the I-beam flange plate. Tightening the nut 13 connects the end plate 10 to the inside of the flange plate, and then the universal ball bearing 81 is connected to the inside of the end plate 10.

[0079] Understandably, during the out-of-plane bending moment loading process, the I-beam specimen 1 will undergo corresponding lateral bending deformation, causing the upper and lower flange plates to tilt. The lugs 71 at both ends of the inner tension jack 7 and the inner tension connector 9, as well as the universal ball joints 81 at both ends of the outer push jack 8 and the end plates 10, can all form a rotational connection. Since the adjustment platform adaptively adjusts the lateral posture of the I-beam specimen in real time, it ensures that the direction of the force applied by the jacks always remains vertical.

[0080] In this embodiment, four out-of-plane loading devices are evenly arranged along the axial direction of the I-beam specimen 1. All the internal pull jacks 7 and external push jacks 8 are driven by the same oil pump. The oil pump outlet is divided into two independently controlled oil circuits, each equipped with a solenoid valve and a proportional pressure reducing valve. The solenoid valve controls the stroke direction of the jacks, while the proportional pressure reducing valve locks the oil pressure ratio at P1:P2=S2:S1 based on the piston area ratio (S1:S2) when the jacks are pushed outward or pulled inward, ensuring that the output force of the internal pull jacks 7 and external push jacks 8 is equal. The two oil circuits are then divided into four by an oil distribution block, synchronously driving the four internal pull jacks and four external push jacks. The return oil after the work is completed is merged again by the oil distribution block and returned to the oil pump through the solenoid valve, forming a closed-loop oil circuit.

[0081] Example 2

[0082] This embodiment discloses a loading method for a composite loading device capable of correcting the attitude of an I-beam. It utilizes the composite loading device for correcting the attitude of an I-beam disclosed in Embodiment 1. The specific steps are as follows:

[0083] When fabricating I-beam specimen 1, symmetrical and equally spaced pre-drilled holes were made, and an inclinometer was installed.

[0084] A buffer airbag was placed on the hinge support and the adjustment platform was fixed. The two ends of the I-beam specimen 1 were placed on the adjustment platform. During the installation process, the hinge support was locked by temporary struts. The inclinometer and the adjustment platform were connected. The adjustment platform was used to adjust the lateral posture of the I-beam specimen 1 and then locked.

[0085] Assemble the out-of-plane loading device and the longitudinal loading device in sequence; remove the temporary support rods and begin loading;

[0086] During loading, longitudinal in-plane bending shear and transverse out-of-plane bending moment loading can be applied to the I-beam specimen 1 simultaneously, or single-mode loading can be applied first, followed by composite loading; for example, the actuator can be used to apply longitudinal in-plane bending shear loading to the I-beam specimen 1 until diagonal cracks appear in the web, then the out-of-plane loading device can be activated to apply a constant transverse bending moment to the web, and then longitudinal in-plane bending shear loading can be continued until the specimen fails.

[0087] During the combined loading, the adjustment platform 4 adaptively adjusts the lateral posture of the I-beam specimen 1 in real time based on the detection results of the two inclinometers, so as to avoid the lateral displacement of the vertical loading ball seat during the combined loading, and thus avoid generating additional torque that would interfere with the test results.

[0088] In this embodiment, longitudinal in-plane bending shear loading uses an actuator to apply a vertical force Fn to the loading ball seat in the first span of the I-beam specimen. Force or displacement control is used, generally force control is used in the early stage of loading, and displacement control is used when failure is imminent. Transverse out-of-plane bending moment loading uses an out-of-plane loading device, which is force controlled. The output force of the jack is changed by adjusting the oil pressure of the jack oil pump. The oil pump outlet is divided into two independently controlled oil circuits and the oil pressure ratio is locked (P1:P2=S2:S1) to ensure that the inner pull jack and the outer push jack apply forces of equal magnitude and opposite direction.

[0089] In this embodiment, when assembling the out-of-plane loading device, the jacks are installed on the inner side of the I-beam specimen 1 in the order of top to bottom; for example, first install the flange bolts 12 at the reserved holes 11 on the top surface of the I-beam specimen 1, then connect the flange bolts 12 to the connecting inner pull connector 9 or end plate 10, and then connect the inner pull connector 9 or end plate 10 to the top of the inner pull jack 7 or the outer push jack 8.

[0090] After all the jacks were suspended and installed on the inner side of the upper flange of the I-beam specimen 1, the jacks were extended by pre-pressurizing with an oil pump and controlling the extension with a solenoid valve to complete the lower connection in sequence. After all the connections were in place, the solenoid valve was used to reciprocate in both directions to depressurize all the jacks.

[0091] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A composite loading device capable of correcting the posture of an I-beam, characterized in that, It includes several out-of-plane loading devices evenly arranged along the axial direction of the I-beam specimen and a longitudinal loading device at the center of the top surface of the I-beam specimen. The out-of-plane loading device includes bidirectional jacks on both sides of the web of the I-beam specimen, namely an inner pull jack and an outer push jack, with the top of the jacks connected to the upper or lower flange of the I-beam specimen; the forces applied by the inner pull jack and the outer push jack are equal in magnitude but opposite in direction; the axial spacing L of the jacks is consistent with the transverse spacing T. The longitudinal loading device includes a loading ball seat at the center of the top surface of the I-beam specimen, and the top surface of the loading ball seat is connected to an actuator perpendicular to the I-beam specimen. One end of the I-beam specimen is mounted on a fixed hinge support, and the other end is mounted on a sliding hinge support; an adjustment platform is provided between the hinge support and the I-beam specimen; and the axis of the adjustment platform is parallel to the axis of the I-beam specimen.

2. The composite loading device for correcting the attitude of an I-beam as described in claim 1, characterized in that, The adjustment platform includes a slidingly connected arc-shaped base and a swing table. The bottom surface of the swing table is provided with an arc-shaped groove, and the top surface of the arc-shaped groove is provided with a worm gear groove. A worm gear meshing with the worm gear groove is rotatably connected inside the arc-shaped base. A stepper motor is installed on the side of the arc-shaped base, and the output shaft of the stepper motor is fixedly connected to the worm gear.

3. The composite loading device for correcting the posture of an I-beam as described in claim 2, characterized in that, Inclinometers are installed on both the upper and lower flange plates; a PLC controller is also installed on the arc-shaped base, the inclinometers are connected to the communication interface of the PLC controller, and the PLC controller is electrically connected to the stepper motor.

4. The composite loading device for correcting the posture of an I-beam as described in claim 2, characterized in that, Both the fixed hinge support and the sliding hinge support include a base, on which a roller is placed, and a top plate is fixedly connected to the roller; the fixed hinge support has limiting strips fixedly connected to the base on both sides of the roller, while the sliding hinge support does not have limiting strips on both sides of the roller; the adjustment platform is fixedly connected to the top plate, and buffer airbags are provided on both sides of the adjustment platform.

5. The composite loading device for correcting the posture of an I-beam as described in claim 4, characterized in that, The fixed hinge support or sliding hinge support is also provided with a temporary support rod on its axial side. The top end of the temporary support rod is bolted to the top plate and the bottom end is bolted to the base, thereby restricting the rotation of the fixed hinge support or sliding hinge support.

6. The composite loading device for correcting the attitude of an I-beam as described in claim 1, characterized in that, The upper and lower flange plates are provided with corresponding reserved holes at their edges. The two ends of the inner pull jack are fixedly connected to lugs, and the two ends of the outer push jack are fixedly connected to universal ball plates. The lugs or universal ball plates are connected to the reserved holes through inner pull connectors or end plates.

7. The composite loading device for correcting the posture of an I-beam as described in claim 6, characterized in that, The inner pull connector includes a U-shaped fork and a pin. The U-shaped fork has a pin hole that matches the earring. After the earring is inserted into the U-shaped fork and aligned, the pin is inserted. The U-shaped fork has a first threaded hole at the end away from the earring. The first threaded hole is threadedly connected to the flange bolt in the reserved hole.

8. The composite loading device for correcting the posture of an I-beam as described in claim 6, characterized in that, Multiple second threaded holes are evenly opened on the edges of the universal ball plate and the end plate. The second threaded holes are threadedly connected to the fixing bolts. A circular through hole and a hexagonal cavity are opened in the center of the end plate. The head of the flange bolt is left in the hexagonal cavity. The shank of the flange bolt passes through the circular through hole, the reserved hole, and the round hole of the pad plate, and is threadedly connected to the nut on the top or bottom surface of the flange plate of the I-beam.

9. The loading method of the composite loading device for correcting the attitude of an I-beam as described in any one of claims 1-8, characterized in that, The specific steps are as follows: When fabricating the I-beam specimen, symmetrical and equally spaced pre-drilled holes are made, and an inclinometer is installed. A buffer airbag is placed on the hinge support and the adjustment platform is fixed. The two ends of the I-beam specimen are placed on the adjustment platform. During the installation process, the hinge support is locked by temporary struts. The inclinometer and the adjustment platform are connected. The adjustment platform adjusts the posture of the I-beam specimen and locks it. Assemble the out-of-plane loading device and the longitudinal loading device in sequence; remove the temporary support rods and begin loading; During loading, the I-beam specimen can be subjected to longitudinal in-plane bending shear and transverse out-of-plane bending moment loading simultaneously, or a single-mode loading can be performed first, followed by a composite loading. During composite loading, the adjustment platform adaptively adjusts the lateral posture of the I-beam specimen in real time based on the detection results of the two inclinometers; and records the loading data when diagonal cracks appear in the web and when the I-beam specimen fails.

10. The loading method of the composite loading device for correcting the attitude of an I-beam as described in claim 9, characterized in that, The longitudinal loading device uses force control in the initial stage of loading and displacement control when the I-beam specimen is close to failure; the out-of-plane loading device uses force control.

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