High-rigidity unbonded collaborative loading system and construction method thereof

Abstract

The application discloses a high-rigidity unbonded cooperative loading system and a construction method thereof, belongs to the technical field of structural engineering test, and is characterized in that opposite-side cooperative steel beams are arranged on opposite sides of a structure to be tested; top-loading steel beams are arranged in a cross shape in the opposite-side cooperative steel beams and are connected with the opposite-side cooperative steel beams at the ends; the top-loading steel beams are double-layer unbonded sleeve pipe assemblies, which comprise an inner square steel pipe and a peripheral round steel pipe sleeved outside the inner square steel pipe, and a preset gap is arranged between the inner square steel pipe and the peripheral round steel pipe; and horizontal prestressed tendons are arranged around the peripheral round steel pipe and are connected with the opposite-side cooperative steel beams at the ends. The high-rigidity unbonded cooperative loading system and the construction method thereof are adopted, the force transmission channel is separated from the fixed interface through the unbonded design of the pipe-in-pipe, and the problems of local buckling, deformation coupling and poor opposite-side cooperativeness of the traditional loading scheme in the super-large tonnage test are solved.

Description

Technical Field

[0001] This invention relates to the field of structural engineering testing technology, and in particular to a high-stiffness unbonded synergistic loading system and its construction method. Background Technology

[0002] In the field of structural engineering, pseudo-dynamic testing is an important research method for studying the mechanical properties of large and complex structures such as super high-rise buildings and long-span bridges under extreme loads such as earthquakes. When conducting pseudo-dynamic tests on ultra-large tonnage structures, such as tests on 1:2 scale models of the core tube of super high-rise buildings, the horizontal force applied by the actuators often reaches thousands of kilonewtons, which places extremely high demands on the loading system.

[0003] In ultra-large tonnage pseudo-dynamic tests, the horizontal force applied by the actuator can reach thousands of kilonewtons. Traditional loading schemes typically use welded steel plate box girders, which have revealed several significant limitations in practical applications: the stress at the actuator loading point is extremely concentrated, and the huge horizontal thrust can easily cause local buckling of the loading steel beam near the loading point, making it impossible to truly and uniformly transfer the applied force to the structure under test, thus affecting the accuracy of the test results. Under the action of huge horizontal forces, the loading steel beam itself will produce significant bending deformation. This deformation is coupled with the displacement response of the structure under test under load, resulting in inaccurate displacement control signals fed back by the sensors inside the actuator, making it difficult to achieve precise control of structural displacement. For large structures requiring double-sided loading, if the loading steel beams on opposite sides cannot achieve synchronous movement, it will lead to unexpected out-of-plane torsion of the structure, introducing an unexpected stress state and seriously interfering with the study of the intrinsic seismic performance of the structure.

[0004] Therefore, in view of the above-mentioned defects of traditional welded steel plate box girders in ultra-large tonnage pseudo-dynamic tests, there is an urgent need to provide a loading system with extremely high stiffness and stability, capable of accurate force and displacement transmission, and able to ensure the synergy of edge loading, so as to provide reliable technical support for seismic testing of large and complex structures. Summary of the Invention

[0005] The purpose of this invention is to provide a high-rigidity unbonded synergistic loading system and its construction method to solve the above-mentioned problems.

[0006] This invention provides a high-stiffness unbonded co-loading system, comprising: The opposite steel beams, in a square shape, are set on the opposite side of the structure to be measured. The top plate loads steel beams, which are arranged in a cross shape within the U-shaped structure of the opposite side cooperating steel beams. Their ends pass through the opposite side cooperating steel beams and are connected to them. The top plate loading steel beam is a double-layer unbonded sleeve assembly, including an inner square steel tube and an outer circular steel tube sleeved on the outside. A preset gap is provided between the inner square steel tube and the outer circular steel tube to achieve unbonded deformation separation. Multiple horizontal prestressing tendons are arranged around the outer circular steel pipe, and their ends are connected to the opposite side cooperating steel beam. The top plate loading steel beam and the opposite side cooperating steel beam are connected as a whole, and a prestressing force is applied.

[0007] Preferably, the gap between the built-in square steel tube and the outer round steel tube is filled with a low-friction polytetrafluoroethylene material layer or a rubber damping layer to further isolate high-frequency vibrations and ensure non-adhesive sliding.

[0008] Preferably, the moment of inertia of the inner square steel tube is greater than that of the outer circular steel tube, which is used to bear the main horizontal shear force and maintain the stiffness of the loading head.

[0009] Preferably, the end of the top plate loading steel beam is provided with a stiffening rib array, which is arranged radially at the end of the outer circular steel pipe, that is, at the connection between the outer circular steel pipe and the opposite side cooperating steel beam, to prevent local buckling under ultra-large tonnage.

[0010] Preferably, the opposite-side coordinating steel beam is a hollow structure, and the stiffening rib array is disposed inside the opposite-side coordinating steel beam.

[0011] A construction method for the high-stiffness unbonded synergistic loading system described above is provided, comprising the following steps: S1, corresponding to the dimensions of the structure to be measured and the estimated loading tonnage, precast top plate loading steel beams, and opposite side cooperative steel beams; S2. The inner square steel tube is coaxially sleeved inside the outer round steel tube, and low friction material is filled in the preset gap between the two to assemble a double-layer unbonded sleeve assembly, i.e., the top plate loading steel beam. S3. Weld a radially arranged array of stiffening ribs at the connection between the outer circular steel pipe and the opposite side cooperating steel beam, and fix the double-layer unbonded sleeve assembly with the welded stiffening rib array in a predetermined position in the opposite side cooperating steel beam. S4. Arrange the horizontal prestressed tendons in the space around the outer circular steel pipe, and apply pre-tightening force at both ends of the tendons to the anchorage end by tensioning. S5. Install the assembled top plate loading steel beam and the opposite side cooperating steel beam on the opposite side of the structure to be tested.

[0012] Therefore, the high-stiffness unbonded synergistic loading system and its construction method described above have the following beneficial effects: (1) High stiffness and precise force transmission: Through a unique "pipe-in-pipe" unbonded design, the core force transmission skeleton, namely the inner square steel pipe, is mechanically separated from the contacting external interface, namely the outer circular steel pipe. As the main load-bearing component, the inner square steel pipe has extremely high moment of inertia and bending and shear stiffness, ensuring that the loading system as a whole has extremely high stiffness. Even if the outer circular steel pipe experiences slight strain under external load, the inner square steel pipe can still maintain linear elastic characteristics, accurately transmitting the force of the actuator to the structure under test, and completely solving the deformation coupling problem of traditional loading beams.

[0013] (2) Strong resistance to local buckling: By setting radially arranged stiffening rib arrays in key stress areas such as loading points and ends, the local stability at the connection between the outer circular steel pipe and the opposite side cooperating steel beam is significantly enhanced, effectively preventing local buckling failure under ultra-large tonnage loads, and ensuring the safety and durability of the loading system.

[0014] (3) High-precision side-to-side coordinated operation: High-strength prestressed tendons arranged in the space around the circular steel pipe are used to connect the top plate loading steel beam and the side-to-side coordinated steel beam into an integral force system. The application of prestressing force eliminates the connection gap, enabling the loading beams on both sides to move synchronously when subjected to dynamic loads, effectively avoiding unexpected structural torsion caused by asynchronous loading, and ensuring the accuracy of the test results.

[0015] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a high-rigidity unbonded collaborative loading system according to the present invention; Figure 2 This is a top view structural schematic diagram of a high-rigidity unbonded collaborative loading system according to the present invention; Figure 3 This is a front structural schematic diagram of a high-rigidity unbonded collaborative loading system according to the present invention; Figure 4 This is a structural schematic diagram of a double-layer unbonded sleeve assembly in a high-rigidity unbonded synergistic loading system according to the present invention; Figure 5 This is a partial structural schematic diagram of a high-stiffness unbonded collaborative loading system according to the present invention.

[0017] Reference numerals: 100, top plate loading steel beam; 110, built-in square steel tube; 120, outer circular steel tube; 130, stiffening rib array; 200, opposite side coordinating steel beam; 300, horizontal prestressed tendon. Detailed Implementation

[0018] To better understand the above technical solutions, a detailed description of the solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0020] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0021] Example 1 like Figure 1 As shown, a high-stiffness unbonded co-loading system is provided, which is mainly used for ultra-large tonnage pseudo-dynamic tests.

[0022] The system includes a top-loaded steel beam 100, a side-coordinating steel beam 200, and a horizontal prestressed tendon 300.

[0023] The opposite side coordinating steel beam 200, in a U-shape, is set on the opposite side of the structure to be tested (such as a super high-rise core tube model); the top plate loading steel beam 100, in a cross shape, is set inside the U-shape of the opposite side coordinating steel beam 200, with its end penetrating through the opposite side coordinating steel beam 200 and connected to it; the top plate loading steel beam 100 is used to transmit the horizontal load applied by the actuator.

[0024] The core of this invention is the double-layer unbonded sleeve assembly of the top plate loading steel beam 100, which is located inside the top plate loading steel beam 100. This assembly includes an inner square steel tube 110 and an outer circular steel tube 120 sleeved on the outside, as shown below. Figure 4As shown, a pre-set annular gap is provided between the built-in square steel tube 110 and the outer circular steel tube 120 to achieve unbonded deformation separation between the two. The built-in square steel tube 110, as the core load-bearing frame, is typically designed with a moment of inertia greater than that of the outer circular steel tube 120, enabling it to withstand the main horizontal shear force and maintain extremely high stiffness during loading, ensuring the stability of the force transmission path. The outer circular steel tube 120 mainly serves as the interface connecting to the top plate loading steel beam 100. To further ensure the unbonded effect and isolate high-frequency vibrations, a low-friction polytetrafluoroethylene material layer or a rubber damping layer is filled within the gap.

[0025] like Figure 2 As shown, to prevent local buckling under ultra-large tonnage loads, a stiffening rib array 130 is provided at the end of the top plate loading steel beam 100, i.e., at the welded joint between the outer circular steel pipe 120 and the opposite cooperating steel beam 200. The stiffening rib array 130 is preferably arranged radially, which can more effectively diffuse localized concentrated stress to a larger area, significantly enhancing the buckling resistance of the joint. Figure 5 As shown.

[0026] The horizontal prestressing tendons 300 can be made of high-strength steel strands or precision-rolled threaded steel, and are arranged around the outer circular steel pipe 120, with both ends anchored to the opposite side cooperating steel beam 200. Figure 3 As shown. By applying prestressing force to the horizontal prestressing tendons 300, the loading beams on both sides can be tightly connected into a whole. When one side is subjected to actuator thrust, this force will be quickly transmitted to the opposite side through the horizontal prestressing tendons 300, thereby ensuring the synchronous movement of the steel beams on both sides and effectively avoiding unexpected torsion of the structure under test due to asynchronous loading.

[0027] Example 2 A construction method for a high-stiffness unbonded synergistic loading system, comprising the following specific steps: S1. Based on the specific dimensions of the structure to be tested and the estimated maximum load tonnage, the specifications of each component are determined through calculation, and the top plate loading steel beam 100, the opposite side cooperating steel beam 200, the internal square steel tube 110, and the external round steel tube 120 are prefabricated. Appropriate installation positions and clearance dimensions are reserved on the internal square steel tube 110 and the external round steel tube 120. S2. Carefully coaxially fit the inner square steel tube 110 inside the outer round steel tube 120, ensuring that the pre-set gap between the two is uniform. Then, according to the design requirements, fill the gap with low-friction polytetrafluoroethylene material or rubber damping layer to form a double-layer unbonded sleeve assembly; S3. At the connection between the outer circular steel pipe 120 and the top plate loading steel beam 100, multiple stiffening ribs are radially welded to form a stiffening rib array 130 to strengthen the critical node; the double-layer unbonded sleeve assembly with the stiffening rib array 130 welded on it is fixedly installed in the predetermined position in the opposite side cooperating steel beam 200. S4. The horizontal prestressing tendons 300 are arranged in the space around the outer circular steel pipe 120, and their two ends are connected to the opposite side cooperating steel beam 200 through anchors. During installation, a special tensioning device is used to tension the horizontal prestressing tendons 300. After reaching the preload value required by the design, they are anchored, thereby connecting the entire system into a whole with high rigidity and high coordination.

[0028] S5. Install the assembled top plate loading steel beam 100 and the opposite side cooperating steel beam 200 on the opposite side of the structure to be tested.

[0029] Therefore, this invention employs the aforementioned high-rigidity unbonded collaborative loading system and its construction method. Through a "pipe-in-pipe" unbonded design, the force transmission channel is separated from the fixed interface. An internal square steel tube serves as the core load-bearing skeleton, providing high rigidity and ensuring precise force transmission. Horizontal prestressed tendons ensure coordinated movement of opposite steel beams, preventing accidental structural torsion. A stiffening rib array effectively prevents local buckling. This solves the problems of local buckling, deformation coupling, and poor coordination between opposite sides in traditional loading schemes for ultra-large tonnage tests, significantly improving the accuracy and reliability of experimental loading.

[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-stiffness unbonded collaborative loading system, characterized in that, include: The opposite side coordinating steel beam (200), in a square shape, is set on the opposite side of the structure to be measured; The top plate loading steel beam (100) is arranged in a cross shape within the square structure of the opposite side cooperating steel beam (200), and its end passes through the opposite side cooperating steel beam (200) and is connected to the opposite side cooperating steel beam (200); The top plate loading steel beam (100) is a double-layer unbonded sleeve assembly, including an inner square steel tube (110) and an outer circular steel tube (120) sleeved on the outside. A preset gap is provided between the inner square steel tube (110) and the outer circular steel tube (120). The end of the top plate loading steel beam (100) is provided with a stiffening rib array (130). Multiple horizontal prestressing tendons (300) are provided and arranged in the space around the outer circular steel pipe (120). Their ends are connected to the opposite side cooperating steel beam (200) and are subjected to prestressing force.

2. The high-stiffness unbonded co-loading system according to claim 1, characterized in that: A filling layer is provided in the gap between the inner square steel pipe (110) and the outer round steel pipe (120).

3. The high-stiffness unbonded co-loading system according to claim 2, characterized in that: The filler layer is either a low-friction polytetrafluoroethylene material layer or a rubber damping layer.

4. The high-stiffness unbonded co-loading system according to claim 1, characterized in that: The moment of inertia of the inner square steel tube (110) is greater than that of the outer circular steel tube (120).

5. The high-stiffness unbonded co-loading system according to claim 1, characterized in that: The stiffening rib array (130) is arranged radially at the ends of the outer circular steel tube (120), that is, at the connection between the outer circular steel tube (120) and the opposite side cooperating steel beam (200).

6. The high-stiffness unbonded co-loading system according to claim 5, characterized in that: The opposite side coordinating steel beam (200) is a hollow structure, and the stiffening rib array (130) is set inside the opposite side coordinating steel beam (200).

7. A construction method for a high-stiffness unbonded synergistic loading system as described in any one of claims 1-6, characterized in that, Includes the following steps: S1, corresponding to the precast top plate loading steel beam (100) and the opposite side cooperating steel beam (200) of the structure to be measured. S2. The inner square steel tube (110) is coaxially sleeved inside the outer round steel tube (120), and low friction material is filled in the preset gap between the two to assemble a double-layer unbonded sleeve assembly, namely the top plate loading steel beam (100). S3. Weld a radially arranged array of stiffening ribs (130) at the connection between the outer circular steel pipe (120) and the opposite side cooperating steel beam (200), and fix the double-layer unbonded sleeve assembly with the welded stiffening rib array (130) in a predetermined position in the opposite side cooperating steel beam (200). S4. Arrange the horizontal prestressed tendons (300) in the space around the outer circular steel pipe (120), and apply prestressing force to both ends by tensioning; S5. Install the assembled top plate loading steel beam (100) and the opposite side cooperating steel beam (200) on the opposite side of the structure to be tested.

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