Testing device for three-dimensional initial stress distribution state of concrete filled steel tube arch rib

Abstract

The invention discloses a testing device for a three-dimensional initial stress distribution state of a concrete filled steel tube arch rib, and relates to the technical field of structural engineering tests. Comprising a base, hinge seats are arranged at the two ends of the upper surface of the base and connected with the two ends of a rotating part respectively, a limiter is connected to the base, and the rotating part is connected with the limiter through a connecting piece; one side of the rotating part is connected with a clamping device; the loading component is used for applying a load to the concrete filled steel tube. The method comprises the following steps: acquiring three-dimensional stress data of a test piece at a certain inclination angle through an inclination sensor and a strain gauge before the strength of concrete is formed; the whole test device is detachable, the angle can be adjusted, the height and the diameter of a test piece can be changed, the construction initial stress can be truly simulated through simple operation, and compared with an existing test device which only applies axial initial stress through a screw, the three-way initial stress caused during construction can be truly simulated, and the three-way stress state of the test piece can be researched.

Description

Technical Field

[0001] The invention relates to the technical field of structural engineering tests, and in particular to a test device for three-dimensional initial stress distribution state of a steel tube concrete arch rib. Background Art

[0002] Concrete-filled steel tube (CFST) is a special type of sleeved concrete with advantages such as high strength, high stiffness, good plasticity, and easy construction. It has been increasingly used in long-span bridges and urban high-rise buildings. However, in both building and bridge construction, CFST construction typically begins with the installation of empty steel tubes, which are then used as formwork for pouring concrete. Therefore, before the concrete and steel tubes form a composite structure, the empty tubes, due to their own weight and the wet weight of unstrengthened concrete, will form initial stresses within the cross-section. Furthermore, during segmental concrete pouring, the initial concrete, after gaining strength, will shrink and creep, affecting the stresses in the tubes. Furthermore, the deadweight of the tubes and the wet weight of concrete in the next segment will also exert forces on the previous segment. These findings indicate that initial stresses in CFST are inevitable during construction. The presence of these initial stresses can prematurely induce the yield phase of the tubes, thereby affecting the mechanical properties of CFST structures and ultimately leading to a decrease in the bearing capacity of the specimens, posing a safety hazard.

[0003] In existing test devices, the simulation of the initial stress of steel tube concrete construction cannot reflect the initial stress state under real conditions. Most tests use screws to apply loads to the specimens in the vertical direction to simulate the initial stress, but this only simulates the axial initial stress. In fact, the steel tube concrete structures in actual projects are not all vertical structures. For the arch ribs of steel tube concrete arch bridges, the inclination angle of each segment is different. Pouring concrete in this state will cause stress in the steel pipe in the axial, radial and circumferential directions. This is different from the force caused by pouring concrete vertically and applying screw loads to the steel pipe. Vertical pouring and loading cannot truly reflect the initial stress of construction. Therefore, there is an urgent need for a test device that can study the initial stress of steel tube concrete construction and truly reflect the initial stress of construction. Summary of the Invention

[0004] The main purpose of the present invention is to provide a test device for the three-dimensional initial stress distribution state of steel tube concrete arch ribs. The angle of the test piece is changed by rotating parts, the angle is limited by a limiter, the height of the test piece is changed by controlling the telescopic distance of the telescopic rod, and the diameter of the test piece is changed by adjusting the spacing of the clamps. In this way, for test pieces of different sizes, the real initial stress of construction can be simulated by a single device, the test efficiency and economic benefits are improved, and the simulated initial stress of construction can be analyzed in three dimensions. During loading, multiple screws are used to apply load to the oblique test piece. After holding the load for a period of time, concrete is poured. Finally, the axial, radial and circumferential stress changes of the test piece at a certain angle are obtained by using an inclination sensor and a strain gauge to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A test device for the three-dimensional initial stress distribution state of a steel tube concrete arch rib comprises a base, wherein both ends of the upper surface of the base are provided with hinge seats, the two hinge seats are respectively connected to the two ends of a rotating component, the base is connected to a limiter, and the rotating component is connected to the limiter via a connector; a clamp is connected to one side of the rotating component;

[0007] The invention also comprises a loading component, which is used to apply load to the steel tube concrete.

[0008] Furthermore, the rotating component includes a rectangular block, a first telescopic rod and a second telescopic rod. The rectangular block is hollow inside, one end of the rectangular block is hinged to a hinge seat on the base, the first telescopic rod is fixedly inserted inside the rectangular block, the free end of the first telescopic rod is connected to a fixed block, the fixed end of the second telescopic rod is hinged to a hinge seat set away from the rectangular block, and the free end of the second telescopic rod is hinged to one side of the fixed block.

[0009] Furthermore, a hinge sleeve is fixedly provided on the second telescopic rod, one end of the connecting member is hinged to the hinge sleeve, and the other end is hinged to the limiter.

[0010] Furthermore, the limiter includes a slider, a slide groove is provided on the base, a slider and a bolt are slidably connected in the slide groove, a bolt hole is provided on the slider, the bolt is threadedly connected in the bolt hole, a nut for positioning the slider is connected to the bolt, a limiting hinge is provided on the slider, and the limiting hinge is hinged to the end of the connecting member.

[0011] Furthermore, the sides of the rectangular block and the fixed block are connected with buckles, and the buckles are used to fix the clamper.

[0012] Furthermore, the clamp includes an inner ring and an outer ring, and opposite ends of the outer ring are fixedly connected with round rods, and the round rods are used to fix the outer ring, and the inner ring is connected to the inside of the outer ring.

[0013] Furthermore, the inner ring includes two symmetrically arranged arc rings, the arc rings are made of spring steel material, each of the arc rings is rotatably connected to a threaded rod, and the outer ring is symmetrically provided with two threaded holes, each threaded hole is threadedly connected to a threaded rod, and the angle between adjacent threaded rods and round rods is 90°.

[0014] Furthermore, the loading component includes a pad, a high-strength screw and a high-strength nut. A pad is provided at each end of the steel tube concrete. The two pads are connected by a high-strength screw. The high-strength nut is connected to the high-strength screw. The high-strength nut is used to apply load to the steel tube concrete.

[0015] Furthermore, it also includes a measuring device group, which includes an inclination sensor and a strain gauge connected to the device, the inclination sensor is used to measure the inclination angle of the steel tube concrete specimen, and the strain gauge is used to measure the axial, circumferential and radial stresses of the steel tube concrete specimen.

[0016] Furthermore, it also includes an outer box, which is a box structure with an open top, the base is fixedly connected to the inside of the outer box, and a ground anchor hole is provided at the bottom end of the outer box.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The first and second telescopic rods cooperate to adjust the rotating parts, allowing the steel tube concrete to be tilted at any vertical angle. When applying load and pouring concrete, the generation of initial construction stress can be truly reflected, solving the current situation that there is no test device that can truly reflect the initial construction stress.

[0019] 2. It can keep the specimen at a specific angle when applying load to the screw or pouring concrete, ensuring the accuracy of the test data at each angle.

[0020] 3. Through the control of the limiter and the rotating parts, any angle can be adjusted. Only one device can accurately simulate the initial stress of the arch rib segments with different inclination angles, making the test more economical and efficient.

[0021] 4. Both the specimen clamping diameter and the specimen clamping height can be changed, and specimens of different sizes can be tested, making the test more extensive.

[0022] 5. The device is mainly connected by bolts or nuts, which is detachable and easy to store. It is also reusable and has high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The overall schematic diagram of the test device.

[0024] Figure 2 This is a schematic diagram of the outer box.

[0025] Figure 3 A schematic diagram of the base.

[0026] Figure 4 Schematic diagram of the structure of the rotating parts.

[0027] Figure 5 Schematic diagram of the structure of the limiter.

[0028] Figure 6 Schematic diagram of the structure of the clamp.

[0029] Figure 7 A schematic diagram of the loading component structure.

[0030] Among them, 1-outer box; 11-ground anchor hole; 2-base; 21-slide; 3-rotating component; 31-rectangular block; 32-first telescopic rod; 33-ring buckle; 34-second telescopic rod; 35-fixed block; 4-loading component; 41-high-strength screw; 42-high-strength nut; 43-pad; 5-limiter; 51-slider; 52-bolt; 6-clamp; 61-outer ring; 62-inner ring; 63-threaded rod; 64-round rod; 7-test piece. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0032] Example

[0033] Combine Figure 1 The present invention provides a test device for the three-dimensional initial stress distribution state of steel tube concrete arch ribs, including a base 2, which is a steel structure. Both ends of the upper surface of the base 2 are provided with hinge seats, and the two hinge seats are respectively connected to the two ends of a rotating part 3. The base 2 is connected to a limiter 5, and the rotating part 3 is connected to the limiter 5 through a connecting part; a clamp 6 is connected to one side of the rotating part 3; and a loading part 4 is also included, and the loading part 4 is used to apply a load to the steel tube concrete specimen.

[0034] Specimen 7 is a steel tube concrete structure. Specimen 7 is made of ordinary steel and concrete, and the four screws 41 used to apply the load are made of high-strength steel. After the initial stress is applied, the axial, radial and hoop stresses are analyzed.

[0035] The rotating component 3 includes a rectangular block 31, a first telescopic rod 32 and a second telescopic rod 34. The rectangular block 31 is a steel structure and is hollow inside. One end of the rectangular block 31 is hinged to a hinge seat on the base 2. The first telescopic rod 32 is fixedly inserted into the inside of the rectangular block 31. The free end of the first telescopic rod 32 is connected to a fixed block 35. The fixed end of the second telescopic rod 34 is hinged to the hinge seat set away from the rectangular block 31, and the free end of the second telescopic rod 34 is hinged to one side of the fixed block 35.

[0036] After adjusting the telescopic distance of the two telescopic rods, rotate the rotating part 3 to the specified angle, then slide the slider 51 on the base 2 to the appropriate position, tighten the bolt on the slider 51 with a nut, and fix the slider 51 to ensure that the angle of the rotating part 3 is fixed.

[0037] An articulated sleeve is fixedly provided on the second telescopic rod 34 , one end of the connecting member is hinged to the articulated sleeve, and the other end is hinged to the limiter 5 ; the limiter cooperates with the connecting member to fix the position of the articulated sleeve, and the articulated sleeve also fixes the position of the rotating component 3 .

[0038] The limiter 5 includes a slider 51, and a slide groove 21 is provided along the length direction of the base 2. The slider 51 and the bolt are slidably connected in the slide groove 21. Four bolt holes are provided on the slider 51, and the bolts are threadedly connected in the bolt holes. The bolts are connected to nuts for positioning the slider. Through 8 nuts, 4 nuts on the upper and lower sides are respectively connected to the bolts passing through the slider. The slider 51 can be fixed by tightening the 8 nuts, thereby controlling the slider 51 to slide and be fixed in the slide groove. A limited hinge seat is provided on the slider 51, and the limited hinge seat is hinged to the end of the connecting member.

[0039] The sides of the rectangular block 31 and the fixing block 35 are both connected with buckles 33 , and the buckles 33 are used to fix the holder 6 . The buckles 33 are made of high-strength steel and are fixed to the holder 6 by bolts.

[0040] The clamp 6 includes an inner ring 62 and an outer ring 61. The opposite ends of the outer ring 61 are fixedly connected with round rods 64. The round rods 64 are used to fix the outer ring 61 on the ring buckle 33, that is, the round rods 64 are placed inside the ring buckle 33, and the ring buckle 33 is fixed by bolts to achieve stable fixation of the clamp 6. The inner ring 62 is connected to the inside of the outer ring 61.

[0041] The inner ring 62 includes two symmetrically arranged arc rings, which are made of spring steel. A threaded rod 63 is rotatably connected to each of the arc rings. Two threaded holes are symmetrically provided on the outer ring 61. A threaded rod 63 is threadedly connected to each threaded hole. The angle between adjacent threaded rods 63 and round rods 64 is 90°. The position of the arc ring is adjusted by rotating the threaded rod 63. The spacing between the two arc rings can be adjusted according to the size of the specimen. After moving to the appropriate position, the threaded rod 63 is fixed with a nut. When fixing the specimen 7, the arc ring can be rotated to a suitable fixed position. In addition, the inner ring 62 is also a spring steel structure with elasticity. It can further enhance the fixing effect of the clamp 6 on the test pieces 7 of different diameters through a certain degree of elastic deformation.

[0042] The loading component 4 includes a pad 43, a high-strength screw 41 and a high-strength nut 42. A pad 43 is provided at each end of the steel tube concrete. The two pads are connected by four high-strength screws 43. The high-strength nut 42 is connected to the high-strength screw 41. The high-strength nut 42 is used to apply a load to the steel tube concrete; the load is applied by tightening the high-strength nut 42, and the load is transferred to the pad 43 by the high-strength screw 41, and then the pad 43 transfers the force to the specimen 7.

[0043] It also includes a measuring device group, which includes an inclination sensor and a strain gauge connected to the device. The inclination sensor is used to measure the inclination angle of the steel tube concrete specimen 7, and the strain gauge is used to measure the axial, circumferential and radial stresses of the steel tube concrete specimen 7.

[0044] The inclination sensor is arranged in the axial direction of the test piece and can read the inclination angle of the test piece. The strain gauges are arranged in the axial, radial and circumferential directions of the test piece to analyze its three-dimensional stress state. In addition, strain gauges are also arranged on the four high-strength screws 41 of the loading component 4 to measure the magnitude of the applied initial stress.

[0045] It also includes an outer box 1, which is made of steel. The outer box 1 is a box structure with an open top, and the internal space is used to accommodate the entire test device. The base 2 is fixedly connected to the inside of the outer box 1, and a ground anchor hole 11 is provided at the bottom end of the outer box 1. Before the test, the outer box 1 is anchored to the ground anchor through the ground anchor hole 11 and bolts to ensure that the entire test device has sufficient stability.

[0046] The entire device is mainly connected by bolts or nuts, so it is detachable. The disassembled parts can be sorted and placed in the outer box 1, which is convenient for transportation and reuse next time, and has high economic benefits.

[0047] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A test device for the three-dimensional initial stress distribution state of a steel tube concrete arch rib, characterized in that: It comprises a base, both ends of the upper surface of the base are provided with hinge seats, the two hinge seats are respectively connected to the two ends of the rotating part, the base is connected with a limiter, the rotating part is connected to the limiter through a connecting piece; one side of the rotating part is connected with a clamp; The invention also comprises a loading component, wherein the loading component is used to apply load to the steel tube concrete.

2. A test device for three-dimensional initial stress distribution state of a steel tube concrete arch rib as claimed in claim 1, characterized in that: The rotating component includes a rectangular block, a first telescopic rod and a second telescopic rod. The rectangular block is hollow inside, one end of the rectangular block is hinged to an articulated seat on the base, the first telescopic rod is fixedly inserted inside the rectangular block, the free end of the first telescopic rod is connected to a fixed block, the fixed end of the second telescopic rod is hinged to a hinged seat arranged away from the rectangular block, and the free end of the second telescopic rod is hinged to one side of the fixed block.

3. A test device for three-dimensional initial stress distribution state of a steel tube concrete arch rib as claimed in claim 2, characterized in that: An articulated sleeve is fixedly arranged on the second telescopic rod, one end of the connecting member is hinged to the articulated sleeve, and the other end is hinged to the limiter.

4. A test device for three-dimensional initial stress distribution state of a steel tube concrete arch rib as claimed in claim 3, characterized in that: The limiter includes a slider, a slide groove is provided on the base, a slider and a bolt are slidably connected in the slide groove, a bolt hole is provided on the slider, the bolt is threadedly connected in the bolt hole, a nut for positioning the slider is connected to the bolt, a limit hinge seat is provided on the slider, and the limit hinge seat is hinged to the end of the connecting piece.

5. A test device for three-dimensional initial stress distribution state of a steel tube concrete arch rib as claimed in claim 4, characterized in that: The sides of the rectangular block and the fixing block are both connected with buckles, and the buckles are used to fix the clamper.

6. A test device for three-dimensional initial stress distribution of concrete-filled steel tube arch ribs as claimed in claim 1, characterized in that: The clamp comprises an inner ring and an outer ring. The two opposite ends of the outer ring are fixedly connected with round rods, and the round rods are used to fix the outer ring. The inner ring is connected to the inside of the outer ring.

7. A test device for three-dimensional initial stress distribution of concrete-filled steel tube arch ribs as claimed in claim 6, characterized in that: The inner ring includes two symmetrically arranged arc rings, which are made of spring steel. A threaded rod is rotatably connected to each of the arc rings. Two threaded holes are symmetrically arranged on the outer ring. A threaded rod is threadedly connected in each threaded hole. The angle between adjacent threaded rods and round rods is 90°.

8. A test device for three-dimensional initial stress distribution of concrete-filled steel tube arch ribs as claimed in claim 1, characterized in that: The loading component includes a pad, a high-strength screw and a high-strength nut. A pad is provided at each end of the steel tube concrete. The two pads are connected by a high-strength screw. The high-strength nut is connected to the high-strength screw. The high-strength nut is used to apply load to the steel tube concrete.

9. A test device for three-dimensional initial stress distribution of concrete-filled steel tube arch ribs as claimed in claim 1, characterized in that: It also includes a measuring device group, which includes an inclination sensor and a strain gauge connected to the device. The inclination sensor is used to measure the inclination angle of the steel tube concrete specimen, and the strain gauge is used to measure the axial, circumferential and radial stresses of the steel tube concrete specimen.

10. A test device for three-dimensional initial stress distribution of concrete-filled steel tube arch ribs as claimed in claim 1, characterized in that: It also includes an outer box, which is a box structure with an open top. The base is fixedly connected to the inside of the outer box, and a ground anchor hole is arranged at the bottom of the outer box.

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