Multi-point synchronous multi-working-condition loading test device and method for concrete-filled steel tube arch rib

Abstract

The invention belongs to the technical field of arch rib loading tests, and particularly relates to a multi-point synchronous multi-working-condition loading test device and method for a concrete-filled steel tube arch rib, and the device comprises a counter-straining beam, a fixed seat, a counter-force frame and a loading assembly; the loading assembly comprises a counter-force beam, and the counter-force beam is fixedly connected with a counter-force frame; a load sensor and a two-way jack are sequentially mounted on the lower side of the counter-force beam; a surrounding piece is arranged below the two-way jack; a surrounding hole is formed in the surrounding piece; the surrounding hole is obliquely designed, and the arch test piece penetrates through the inside of the surrounding hole. During an experiment, the arch test piece sequentially penetrates through the surrounding holes of the surrounding pieces, the loading assembly at each position can stretch or retract by controlling the two-way jack, pressure, tension or alternating load is applied to the arch test piece through the surrounding pieces, a multi-point synchronous and multi-working-condition loading test is achieved, and a real arch bridge application scene is fully simulated.

Description

Technical Field

[0001] This invention belongs to the field of arch rib loading test technology, specifically a multi-point synchronous multi-condition loading test device and method for steel tube concrete arch ribs. Background Technology

[0002] Concrete-filled steel tubular arch bridges are a widely used structural form in modern bridge engineering. In actual operation, their arch ribs are subjected to complex load conditions resulting from the combined effects of various factors such as vehicles, wind loads, and temperature changes. These loads not only manifest as alternating pressure and tension at multiple points but are also often accompanied by dynamic responses and local vibration effects. To accurately simulate such complex stress states in an experimental environment, a specialized testing device for concrete-filled steel tubular arch ribs is needed to scientifically reproduce the true mechanical behavior of the arch rib structure and provide a reliable basis for assessing structural safety and durability.

[0003] Chinese patent application CN116858468A discloses a large-tonnage multi-condition vertical loading system for an arch. The key technical features are: an arch rib with arch seats at both ends for fixing it to the bottom surface; at least one loading system on the arch rib; a plurality of arch rib clamps fitted onto the arch rib; a limiting mechanism at the contact point between the arch rib clamps and the arch rib for restricting the position of the arch rib clamps; a plurality of first vertical pulleys arranged side-by-side at the lower end of each arch rib clamp; and a first fixing seat directly below each arch rib clamp, fixedly connected to the bottom surface, with a plurality of second vertical pulleys arranged side-by-side on each first fixing seat; and steel wire ropes wound around the first and second vertical pulleys.

[0004] The core drawback of current experimental devices used for studying the in-plane stability of steel-concrete composite arches lies in the simplistic loading modes and the disconnect from actual stress conditions. Existing technologies generally rely on equipment such as hydraulic jacks to apply vertical pressure to the arch ribs to simulate dead and static load conditions. However, this differs significantly from the dynamic stress state of arch bridges in actual operation. When vehicles or other live loads pass over the bridge, they generate complex dynamic effects on the arch structure, causing specific areas of the arch (such as near the arch foot and quarter points) to experience alternating tensile and compressive cyclic stresses. However, existing devices lack the ability to simulate tensile or alternating tensile and compressive loads, resulting in serious deficiencies in experimental research. They cannot reveal the material properties, cross-sectional cracking behavior, and tensile synergy mechanism of the steel-concrete interface under tensile loads. Nor can they assess the long-term performance, stiffness degradation, and dynamic stability of the structure under fatigue loads. Consequently, experimental conclusions cannot fully reflect the true load-bearing capacity and failure mechanism of the structure, hindering the further improvement of design theory and the accurate assessment of engineering safety.

[0005] Therefore, the present invention provides a multi-point synchronous multi-condition loading test device and method for steel tube concrete arch ribs. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0007] The technical solution adopted by the present invention to solve its technical problem is: a multi-point synchronous multi-condition loading test device for steel tube concrete arch ribs, comprising a tie beam, a fixed seat, a reaction frame and a loading component.

[0008] The fixed seats are provided in pairs and fixedly connected to both ends of the tie beam; the reaction frames are provided in a set and evenly distributed above the tie beam;

[0009] The loading components are provided in a set and are respectively arranged between the reaction frames; the loading components are used to perform loading tests on the arch specimen;

[0010] The loading component includes a reaction beam, which is fixedly connected to a reaction frame; a load sensor and a bidirectional jack are sequentially installed on the lower side of the reaction beam; a surrounding component is provided below the bidirectional jack; a surrounding hole is opened inside the surrounding component; the surrounding hole is designed at an angle, and the arched specimen passes through the inside of the surrounding hole.

[0011] Preferably, a support frame is fixedly connected to the lower side of the bidirectional jack; a set of guide rods is fixedly connected inside the support frame; a connector is provided at the top of the enclosure; the guide rods pass through the connector and are slidably connected to it; both the enclosure and the connector are designed as half-separated parts; and hydraulic cylinders are fixedly connected between the connector and the support frame.

[0012] Preferably, a set of rollers are evenly distributed inside the surrounding hole; the rollers are distributed on the upper and lower sides of the arch specimen and fit against it.

[0013] Preferably, the enclosure has a set of grooves inside; a slider is provided inside the grooves; a connecting rod is fixedly connected to one side of the slider, and a compression spring is fixedly connected between the other side and the groove; a bracket is fixedly connected to one end of the connecting rod that extends into the enclosure hole, and a roller is rotatably connected to the bracket.

[0014] Preferably, the slider and the groove are in a sliding seal fit; a hollow shaft is fixedly connected inside the bracket; the hollow shaft passes through the roller and is in a rotating seal fit with it; the hollow shaft is connected to a guide tube, and the other end of the guide tube extends to the surface of the slider; the roller is designed as a hollow structure and is connected to the hollow shaft; a set of slits are evenly distributed on the surface of the roller.

[0015] Preferably, a baffle is fixedly connected to the side of the hollow shaft near the arch specimen, and the baffle is located inside the roller; an air groove connects the hollow shaft and the baffle.

[0016] Preferably, a set of limiting rollers are evenly distributed inside the surrounding hole; the limiting rollers are distributed on both horizontal sides of the arch specimen and are in contact with it.

[0017] Preferably, a limiting frame is provided between the limiting roller and the surrounding component; end plates and connecting posts are fixedly connected to both ends of the limiting frame; the limiting roller is designed as a hollow structure and connecting rings are provided inside both ends; an elastic connecting ring is fixedly connected between the connecting ring and the limiting roller; the connecting rings are respectively sleeved on the outside of the connecting posts and rotate with them; a motor is fixedly connected to the surface of the connecting posts; a wheel is connected to the output shaft of the motor; a set of spring rods and guide balls are evenly distributed on the surface of the wheel; a set of spring pieces are evenly distributed on the inner side of the limiting roller.

[0018] The present invention discloses a method for multi-point synchronous multi-condition loading test of steel-concrete composite arch ribs. This method employs the aforementioned multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs and includes the following steps:

[0019] S1. Arrange the arch specimen between multiple reaction frames. The two ends of the arch specimen are fixedly connected to the fixed base. Control the extension of the hydraulic cylinders of each loading component to push the connecting parts and the surrounding parts to move closer and close to each other so as to place the arch specimen inside the surrounding hole.

[0020] S2. The PLC hydraulic system controls the bidirectional jacks at different positions to work synchronously, driving the surrounding parts to move relative to the arch specimen and continuously applying vertical load to the arch specimen.

[0021] S3. When the arch specimen undergoes in-plane deformation under load, the roller rotates flexibly and compresses the compression spring accordingly, allowing the roller to fully conform to and adapt to the degree of deformation of the arch specimen.

[0022] S4. By setting limit rollers, the arch specimen is laterally constrained to prevent the specimen from deforming outward from the arch plane. When the specimen deforms in the arch plane, the limit rollers rotate accordingly to adapt to the degree of deformation.

[0023] S5. The motor inside the limiting roller drives the wheel, spring rod, and guide ball to rotate. The guide ball continuously hits the surface of the spring, causing the spring to vibrate.

[0024] S6. The vibration effect of the spring sheet is transmitted to the arch specimen through the limiting roller, so that the limiting roller can apply continuous and controllable micro-amplitude vibration to the arch specimen, thus restoring the true stress state of the arch bridge under complex environmental excitation.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. The present invention discloses a multi-point synchronous multi-condition loading test device and method for steel-concrete composite arch ribs. By evenly distributing multiple independent loading components on the tie beam, each component integrates a reaction beam, a load sensor, and a bidirectional jack, and in conjunction with a uniquely designed enclosure, a multi-point synchronous loading system is constructed. During the experiment, the arch specimen is passed through the enclosure holes of each enclosure in sequence. The loading component at each position can be extended or shortened by controlling the bidirectional jack. The enclosure is used to apply pressure, tension, or alternating load to the arch specimen, realizing multi-point synchronous and multi-condition loading tests, fully simulating the real application scenario of arch bridges.

[0027] 2. The multi-point synchronous multi-condition loading test device and method for steel-concrete composite arch ribs described in this invention, by designing both the surrounding parts and connecting parts as separable and closable half-structures, is more conducive to actual operation. By controlling the retraction of the hydraulic cylinder, the pair of connecting parts and the surrounding parts are driven to separate from each other, and then the arch specimen is installed in place, so that the arch specimen is located between the pair of surrounding parts. Then, by controlling the extension of the hydraulic cylinder, the pair of connecting parts and the surrounding parts are pushed closer to each other and reclosed, so as to cover the arch specimen inside the surrounding hole, thereby improving the installation or disassembly efficiency of the arch specimen.

[0028] 3. The multi-point synchronous multi-condition loading test device and method for steel-concrete composite arch ribs described in this invention, by setting rollers inside the enclosure that fit against the surface of the arch specimen, allows the rollers to rotate flexibly when the arch specimen undergoes axial deformation under load, thereby effectively releasing the deformation constraint of the arch specimen in the length direction. This ensures that the loading force is continuously and uniformly transmitted to the arch specimen through the enclosure, while avoiding the limitation of specimen deformation by traditional fixed connection methods and reducing the interference of the test device's own stiffness on the measurement results. Attached Figure Description

[0029] The invention will now be further described with reference to the accompanying drawings.

[0030] Figure 1 This is a perspective view of the present invention;

[0031] Figure 2 This is a schematic diagram of the loading component in this invention;

[0032] Figure 3 This is a schematic diagram of the structure after the surrounding component is separated in this invention;

[0033] Figure 4 This is a schematic diagram of the structure of the roller and the limiting roller in this invention;

[0034] Figure 5 This is a cross-sectional view of the surrounding component in this invention;

[0035] Figure 6This is a cross-sectional view of the roller in this invention;

[0036] Figure 7 This is a schematic diagram of the structure of the limiting roller in this invention;

[0037] Figure 8 This is a cross-sectional view of the limiting roller in this invention;

[0038] Figure 9 This is a schematic diagram of the method flow of the present invention.

[0039] In the diagram: 1. Tie beam; 2. Fixed seat; 3. Reaction frame; 4. Loading assembly; 5. Arch specimen; 41. Reaction beam; 42. Load sensor; 43. Bidirectional jack; 44. Enclosing component; 45. Enclosing hole; 46. Support frame; 47. Guide rod; 48. Connector; 49. Hydraulic cylinder; 50. Roller; 51. Slide groove; 52. Slider; 53. Connecting rod; 54. Compression spring; 55. Bracket; 56. Hollow shaft; 57. Guide tube; 58. Slit; 59. Cover; 60. Air groove; 61. Limiting roller; 62. Limiting frame; 63. End plate; 64. Connecting column; 65. Connecting ring; 66. Elastic connecting ring; 67. Motor; 68. Wheel; 69. Spring rod; 70. Guide ball; 71. Spring piece. Detailed Implementation

[0040] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0041] like Figures 1 to 8 As shown, the multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs of the present invention includes a tie beam 1, a fixed seat 2, a reaction frame 3, and a loading component 4.

[0042] The fixed base 2 is provided in pairs and fixedly connected to both ends of the tie beam 1; the reaction frame 3 is provided in a set and evenly distributed above the tie beam 1;

[0043] The loading assembly 4 is provided in a set and is respectively arranged between the reaction frames 3; the loading assembly 4 is used to perform loading tests on the arch specimen 5;

[0044] The loading component 4 includes a reaction beam 41, which is fixedly connected to the reaction frame 3. A load sensor 42 and a bidirectional jack 43 are sequentially installed on the lower side of the reaction beam 41. A surrounding component 44 is provided below the bidirectional jack 43. A surrounding hole 45 is provided inside the surrounding component 44. The surrounding hole 45 is designed to be inclined, and the arch specimen 5 passes through the interior of the surrounding hole 45. The loading components 4 at different positions have different heights and different degrees of inclination of the surrounding hole 45 to adapt to the local shape of the arch specimen 5.

[0045] The core drawback of current experimental devices used for studying the in-plane stability of steel-concrete composite arches lies in the simplistic loading modes and the disconnect from actual stress conditions. Existing technologies generally rely on equipment such as hydraulic jacks to apply vertical pressure to the arch ribs to simulate dead and static load conditions. However, this differs significantly from the dynamic stress state of arch bridges in actual operation. When vehicles or other live loads pass over the bridge, they generate complex dynamic effects on the arch structure, causing specific areas of the arch (such as near the arch foot and quarter points) to experience alternating tensile and compressive cyclic stresses. However, existing devices lack the ability to simulate tensile or alternating tensile and compressive loads, resulting in serious deficiencies in experimental research. They cannot reveal the material properties, cross-sectional cracking behavior, and tensile synergy mechanism of the steel-concrete interface under tensile loads. Nor can they assess the long-term performance, stiffness degradation, and dynamic stability of the structure under fatigue loads. Consequently, experimental conclusions cannot fully reflect the true load-bearing capacity and failure mechanism of the structure, hindering the further improvement of design theory and the accurate assessment of engineering safety.

[0046] This invention constructs a multi-point synchronous loading system by evenly distributing multiple independent loading components 4 on the tie beam 1. Each component integrates a reaction beam 41, a load sensor 42, and a bidirectional jack 43, and works in conjunction with a uniquely designed enclosure 44. During the experiment, the arch specimen 5 is passed through the enclosure holes 45 of each enclosure 44 in sequence. The loading component 4 at each position can be extended or shortened by controlling the bidirectional jack 43. The enclosure 44 is used to apply pressure, tension, or alternating load to the arch specimen 5, realizing multi-point synchronous and multi-condition loading tests, and fully simulating the real arch bridge application scenario.

[0047] This invention enables researchers to precisely control the application of dynamic loads, such as pressure, tension, or alternating tension and compression, to each loading point on the arch specimen 5 according to the actual stress simulation requirements of bridges. This not only greatly enriches and expands the range of test conditions, but also realistically simulates the complex stress state of arch bridges under live loads such as vehicle traffic. This provides a reliable technical means for in-depth research on the dynamic response, fatigue performance, and stress mechanism of steel-concrete composite arches, significantly improving the simulation accuracy and engineering guidance value of the test data.

[0048] This invention employs a centralized hydraulic system to drive the bidirectional jacks 43 of multiple loading components 4, and introduces a programmable logic controller (PLC) for overall control. The PLC system can perform high-precision and automated synchronous management of the force application process of all loading points according to a preset program. This not only ensures the precise consistency of the load size and loading rate at each point and effectively eliminates human error, but also enables complex loading sequences and load spectra, which helps to improve the accuracy of loading force and the reliability of test data, providing a solid foundation for simulating structural response under real working conditions.

[0049] In one embodiment of the present invention, a support frame 46 is fixedly connected to the lower side of the bidirectional jack 43; a set of guide rods 47 are fixedly connected inside the support frame 46; a connector 48 is provided on the top of the enclosure 44; the guide rods 47 pass through the connector 48 and are slidably connected to it; both the enclosure 44 and the connector 48 are designed as half-separated parts; a hydraulic cylinder 49 is fixedly connected between the connector 48 and the support frame 46.

[0050] By designing both the surrounding member 44 and the connecting member 48 as a separable and foldable half-structure, it is more conducive to actual operation. By controlling the retraction of the hydraulic cylinder 49, the pair of connecting members 48 and the surrounding member 44 are driven to separate from each other. Then, the arch specimen 5 is installed in place, so that the arch specimen 5 is located between the pair of surrounding members 44. Afterwards, by controlling the extension of the hydraulic cylinder 49, the pair of connecting members 48 and the surrounding member 44 are pushed closer to each other and re-closed, so as to cover the arch specimen 5 inside the surrounding hole 45, thereby improving the installation or disassembly efficiency of the arch specimen 5.

[0051] In one embodiment of the present invention, a set of rollers 50 are evenly distributed inside the surrounding hole 45; the rollers 50 are distributed on the upper and lower sides of the arch specimen 5 and fit with it.

[0052] By setting rollers 50 inside the enclosure 44 that fit against the surface of the arch specimen 5, the rollers 50 can rotate flexibly when the arch specimen 5 undergoes axial deformation under load, thereby effectively releasing the deformation constraint of the arch specimen 5 in the length direction. This ensures that the loading force is continuously and uniformly transmitted to the arch specimen 5 through the enclosure 44, while avoiding the limitation of specimen deformation by the traditional fixed connection method and reducing the interference of the stiffness of the test device itself on the measurement results.

[0053] The enclosing member 44 has a set of sliding grooves 51 inside, and each sliding groove 51 corresponds to a roller 50. A slider 52 is provided inside the sliding groove 51. A connecting rod 53 is fixedly connected to one side of the slider 52, and a compression spring 54 is fixedly connected between the other side and the sliding groove 51. A bracket 55 is fixedly connected to one end of the connecting rod 53 that extends into the enclosing hole 45, and the roller 50 is rotatably connected to the bracket 55.

[0054] Through the coordinated action of slider 52, connecting rod 53, compression spring 54 and roller 50, an intelligent contact system capable of dynamically responding to specimen deformation is constructed. When the surrounding member 44 moves upward or downward, the arch specimen 5 can squeeze a set of rollers 50 below or above it. The rollers 50 and connecting rod 53 drive slider 52 to move inside the groove 51, so as to adaptively compress compression spring 54. Therefore, no matter how the loading direction changes, the pressure of compression spring 54 can continuously push roller 50 to keep it in close contact with the surface of arch specimen 5, eliminating the contact gap caused by the deformation of arch specimen 5. This not only effectively avoids the problem of local stress concentration caused by traditional rigid contact, but also adapts to the complex curved surface deformation of arch specimen 5 in the arch plane during loading, ensuring the continuity and uniformity of load transfer.

[0055] In one embodiment of the present invention, the slider 52 and the groove 51 are in a sliding sealed fit; a hollow shaft 56 is fixedly connected inside the bracket 55; the hollow shaft 56 passes through the roller 50 and is in a rotating sealed fit with it; the hollow shaft 56 is connected to a conduit 57, and the other end of the conduit 57 extends to the surface of the slider 52; the roller 50 is designed as a hollow structure and is connected to the hollow shaft 56; a set of slits 58 are evenly distributed on the surface of the roller 50.

[0056] When the arch specimen 5 moves the slider 52 inside the groove 51 via the roller 50 and connecting rod 53, the slider 52 can squeeze the air in the groove 51. The compressed air then enters the hollow shaft 56 and the inside of the roller 50 through the conduit 57 and is ejected outward along the slit 58 on the surface of the roller 50. This airflow blows away any dust, concrete residue, or other particulate matter that may be present in the gap between the roller 50 and the arch specimen 5, maintaining the cleanliness of the mechanical interface between the roller 50 and the arch specimen 5. This effectively solves the problem of impurities accumulating and affecting mechanical transfer during the test, and prevents these tiny particles from accumulating on the contact surface to form local fulcrums. This ensures that the roller 50 always rotates smoothly, eliminates the additional frictional constraints caused by impurities, and makes the load transfer more in line with the theoretically preset boundary conditions.

[0057] A baffle 59 is fixedly connected to the side of the hollow shaft 56 near the arch specimen 5, and the baffle 59 is located inside the roller 50; an air groove 60 connects the hollow shaft 56 and the baffle 59.

[0058] When compressed air enters the roller 50 along the hollow shaft 56 and the air groove 60, the baffle 59 can concentrate and focus the air. No matter what angle the roller 50 rotates to, the baffle 59 can guide the airflow toward the arched specimen 5, so as to increase the utilization of the airflow and the blowing force, and improve the removal efficiency of particles between the roller 50 and the arched specimen 5.

[0059] In one embodiment of the present invention, a set of limiting rollers 61 are evenly distributed inside the surrounding hole 45; the limiting rollers 61 are distributed on both horizontal sides of the arch specimen 5 and are in contact with it.

[0060] By setting horizontally symmetrically distributed limiting rollers 61, a lateral constraint mechanism is formed on the arch specimen 5 to prevent the specimen from deforming outward from the arch plane. When the specimen deforms in the arch plane, the limiting rollers 61 can rotate accordingly to adapt to the deformation. This can not only accurately prevent the arch specimen 5 from instability outward from the plane, but also eliminate the constraint on the deformation in the test plane of the arch specimen 5 through the follow-up rotation characteristics, so that the specimen can undergo free deformation in a state closer to the real boundary conditions, ensuring that the test data can more accurately reflect the actual mechanical response and instability mechanism of the arch structure.

[0061] A limiting frame 62 is provided between the limiting roller 61 and the surrounding member 44; both ends of the limiting frame 62 are fixedly connected to end plates 63 and connecting posts 64; the limiting roller 61 is designed as a hollow structure and both ends are provided with connecting rings 65; an elastic connecting ring 66 is fixedly connected between the connecting ring 65 and the limiting roller 61; the connecting rings 65 are respectively sleeved on the outside of the connecting posts 64 and rotate with them; a motor 67 is fixedly connected to the surface of the connecting posts 64; the output shaft of the motor 67 is connected to a wheel 68; a set of spring rods 69 are evenly distributed on the surface of the wheel 68; a guide ball 70 is fixedly connected to the end of the spring rod 69; a set of protruding spring pieces 71 are evenly distributed on the inner side of the limiting roller 61 at the corresponding position of the wheel 68.

[0062] During the experiment, the motor 67 inside the limiting roller 61 drives the wheel 68, multiple spring rods 69, and guide ball 70 to rotate. The guide ball 70 then continuously impacts the surface of the spring piece 71, causing the spring piece 71 to vibrate. This vibration effect is transmitted to the arch specimen 5 through the limiting roller 61, allowing the limiting roller 61 to apply continuous and controllable micro-amplitude vibration to the arch specimen 5. This dynamic vibration loading condition effectively restores the real stress state of the arch bridge under complex environmental excitation such as vehicle traffic and wind load, and effectively stimulates the cumulative damage characteristics of the structure under complex actions, providing technical support for studying the fatigue performance, dynamic stability, and long-term service behavior of arch bridges.

[0063] like Figure 9 As shown, the present invention provides a method for multi-point synchronous multi-condition loading test of steel-concrete composite arch ribs. This method utilizes the aforementioned multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs and includes the following steps:

[0064] S1. Arrange the arch specimen 5 between multiple reaction frames 3. The two ends of the arch specimen 5 are fixedly connected to the fixed base 2 respectively. Control the extension of the hydraulic cylinder 49 of each loading component 4 to push the connecting piece 48 and the surrounding piece 44 to move closer to each other and close together so as to place the arch specimen 5 inside the surrounding hole 45.

[0065] S2. The PLC hydraulic system controls the bidirectional jacks 43 at different positions to work synchronously, driving the surrounding part 44 to move relative to the arch specimen 5, and continuously applying vertical load to the arch specimen 5.

[0066] S3. When the arch specimen 5 undergoes in-plane deformation under load, the roller 50 rotates flexibly and compresses the compression spring 54 accordingly, so that the roller 50 fully fits and adapts to the degree of deformation of the arch specimen 5.

[0067] S4. By setting the limiting roller 61, the arch specimen 5 is laterally constrained to prevent the specimen from deforming outward from the arch plane. When the specimen deforms in the arch plane, the limiting roller 61 rotates accordingly to adapt to the degree of deformation.

[0068] S5. The motor 67 inside the limiting roller 61 drives the wheel 68, spring rod 69, and guide ball 70 to rotate. The guide ball 70 continuously hits the surface of the spring piece 71, causing the spring piece 71 to vibrate.

[0069] The vibration effect of S6 and spring 71 is transmitted to the arch specimen 5 through the limiting roller 61, so that the limiting roller 61 can apply continuous and controllable micro-amplitude vibration to the arch specimen 5, thus restoring the true stress state of the arch bridge under complex environmental excitation.

[0070] The terms "front," "back," "left," "right," "top," and "bottom" all refer to the figures in the accompanying drawings. Figure 1 Based on the perspective of the observer, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0071] In the description of this invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0072] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present 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 the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs, characterized in that: It includes a tie beam (1), a fixed seat (2), a reaction frame (3), and a loading assembly (4); The fixed base (2) is provided in pairs and fixedly connected to both ends of the tie beam (1); the reaction frame (3) is provided in a set and evenly distributed above the tie beam (1); The loading assembly (4) is provided in a set and is arranged between the reaction frames (3); the loading assembly (4) is used to perform loading tests on the arch specimen (5); The loading component (4) includes a reaction beam (41), which is fixedly connected to the reaction frame (3); a load sensor (42) and a bidirectional jack (43) are installed on the lower side of the reaction beam (41); a surrounding component (44) is provided below the bidirectional jack (43); a surrounding hole (45) is provided inside the surrounding component (44); the surrounding hole (45) is inclined, and the arch specimen (5) passes through the inside of the surrounding hole (45).

2. The multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs according to claim 1, characterized in that: The bidirectional jack (43) is fixedly connected to a support frame (46) on its lower side; a set of guide rods (47) is fixedly connected inside the support frame (46); a connector (48) is provided on the top of the enclosure (44); the guide rods (47) pass through the connector (48) and are slidably connected to it; both the enclosure (44) and the connector (48) are designed as half-separated parts; a hydraulic cylinder (49) is fixedly connected between the connector (48) and the support frame (46).

3. The multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs according to claim 2, characterized in that: A set of rollers (50) are evenly distributed inside the surrounding hole (45); the rollers (50) are distributed on the upper and lower sides of the arch specimen (5) and fit with it.

4. The multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs according to claim 3, characterized in that: The enclosure (44) has a set of grooves (51) inside; a slider (52) is provided inside the groove (51); a connecting rod (53) is fixedly connected to one side of the slider (52), and a compression spring (54) is fixedly connected between the other side and the groove (51); a bracket (55) is fixedly connected to one end of the connecting rod (53) that extends into the enclosure hole (45), and the roller (50) is rotatably connected to the bracket (55).

5. The multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs according to claim 4, characterized in that: The slider (52) and the groove (51) are in a sliding seal fit; a hollow shaft (56) is fixedly connected inside the bracket (55); the hollow shaft (56) passes through the roller (50) and rotates in a seal fit with it; the hollow shaft (56) is connected to a conduit (57), and the other end of the conduit (57) extends to the surface of the slider (52); the roller (50) is designed as a hollow structure and is connected to the hollow shaft (56); a set of slits (58) are evenly distributed on the surface of the roller (50).

6. The multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs according to claim 5, characterized in that: A baffle (59) is fixedly connected to the side of the hollow shaft (56) near the arch specimen (5), and the baffle (59) is located inside the roller (50); an air groove (60) is connected between the hollow shaft (56) and the baffle (59).

7. The multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs according to claim 6, characterized in that: A set of limiting rollers (61) are evenly distributed inside the surrounding hole (45); the limiting rollers (61) are distributed on both horizontal sides of the arch specimen (5) and are in contact with it.

8. The multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs according to claim 7, characterized in that: A limiting frame (62) is provided between the limiting roller (61) and the surrounding part (44); both ends of the limiting frame (62) are fixedly connected to end plates (63) and connecting columns (64); the limiting roller (61) is designed as a hollow structure and both ends are provided with connecting rings (65); an elastic connecting ring (66) is fixedly connected between the connecting ring (65) and the limiting roller (61); the connecting rings (65) are respectively sleeved on the outside of the connecting columns (64) and rotated with them; a motor (67) is fixedly connected to the surface of the connecting column (64); the output shaft of the motor (67) is connected to a wheel (68); a set of spring rods (69) and guide balls (70) are evenly distributed on the surface of the wheel (68); a set of spring pieces (71) are evenly distributed on the inner side of the limiting roller (61).

9. A method for multi-point synchronous multi-condition loading test of steel-concrete composite arch ribs, wherein the method employs the multi-point synchronous multi-condition loading test device for steel-concrete composite arch ribs as described in claim 8, characterized in that: Includes the following steps: S1. Arrange the arch specimen (5) between multiple reaction frames (3). The two ends of the arch specimen (5) are fixedly connected to the fixed seat (2). Control the extension of the hydraulic cylinder (49) of each loading component (4) to push the connecting piece (48) and the surrounding piece (44) to approach and close each other, so as to place the arch specimen (5) inside the surrounding hole (45). S2. The PLC oil circuit system controls the bidirectional jacks (43) at different positions to work synchronously, driving the surrounding part (44) to move relative to the arch specimen (5) and continuously applying vertical load to the arch specimen (5). S3. When the arch specimen (5) undergoes deformation in the plane of the arch under the load, the roller (50) rotates flexibly and compresses the compression spring (54) accordingly, so that the roller (50) fully fits and adapts to the degree of deformation of the arch specimen (5).

10. A multi-point synchronous multi-condition loading test method for steel-concrete composite arch ribs according to claim 9, characterized in that: It also includes the following steps: S4. By setting a limiting roller (61), the arch specimen (5) is laterally constrained to prevent the specimen from deforming outward from the arch plane. When the specimen deforms in the arch plane, the limiting roller (61) rotates accordingly to adapt to the degree of deformation. S5. The motor (67) inside the limiting roller (61) drives the wheel (68), spring rod (69), and guide ball (70) to rotate. The guide ball (70) continuously hits the surface of the spring piece (71), causing the spring piece (71) to vibrate. S6. The vibration effect of the spring (71) is transmitted to the arch specimen (5) through the limiting roller (61), so that the limiting roller (61) can apply continuous and controllable micro-amplitude vibration to the arch specimen (5) to restore the real stress state of the arch bridge under complex environmental excitation.

Images