A static load testing device and method suitable for a stack lane cantilever beam

Abstract

The application discloses a static load testing device and testing method suitable for a stack way cantilever beam, and relates to the technical field of load testing of stack way cantilever beams. The static load testing device comprises a counter-force frame, a loading device and a data acquisition system. The axis of the counter-force beam is perpendicular to the axis of the measured cantilever beam. The middle part of the counter-force beam is located above the loading point of the measured cantilever beam. The two side sections of the counter-force beam are respectively connected with two groups of counterweight assemblies. The loading axis of the loading device passes through the loading point of the measured cantilever beam and is perpendicular to the axis of the measured cantilever beam and the axis of the counter-force beam. The static load testing method comprises the following steps: controlling the loading device to perform step loading on the measured cantilever beam; when a loading stop sign appears, controlling the loading device to stop loading; and controlling the loading device to perform step unloading on the measured cantilever beam. The application can satisfy safe and reliable detection of the stress state of the stack way cantilever beam in a space-limited environment.

Description

Technical Field

[0001] This invention relates to the field of load testing technology for cantilever beams of walkways, and in particular to a static load testing device and method suitable for cantilever beams of walkways. Background Technology

[0002] Cliffside grotto walkways are typical high-altitude, narrow, and elevated passageways with a long service life, serving both cultural relic protection and public access purposes. The cantilever beams and their anchorage to the rock mass are crucial for load-bearing capacity and safety control. On-site static load testing is a direct and reliable method for assessing structural bearing capacity, examining component deformation and strain response by applying predetermined static loads.

[0003] Existing static testing devices are mostly used for conventional bridges, such as using test vehicles for equivalent loading, but there is a lack of dedicated loading devices and system procedures for cantilever beams of specific cultural relic protection walkways. At the same time, the space of cliff walkways is limited, and existing testing schemes are subject to strong site and safety constraints in terms of equipment installation and load control.

[0004] In view of the problems existing in the prior art, those skilled in the art urgently need a static load testing device and method suitable for cantilever beams of walkways. Summary of the Invention

[0005] The purpose of this invention is to provide a static load testing device and method for cantilever beams of walkways, so as to solve the problems existing in the prior art and to meet the requirements of safe and reliable detection of the stress state of cantilever beams of walkways in space-constrained environments.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a static load testing device suitable for cantilever beams of walkways, comprising a reaction frame, a loading device, and a data acquisition system. The reaction frame includes a reaction beam and counterweight components. Two sets of counterweight components are symmetrically arranged about the axis of the cantilever beam under test. The axis of the reaction beam is perpendicular to the axis of the cantilever beam under test. The middle part of the reaction beam is located above the loading point of the cantilever beam under test. The two side sections of the reaction beam are respectively limited and connected to the two sets of counterweight components. The loading device abuts against the cantilever beam under test and the reaction beam at both ends along the loading axis. The loading axis of the loading device passes through the loading point of the cantilever beam under test and is perpendicular to the axis of both the cantilever beam under test and the axis of the reaction beam. The data acquisition system includes sensors and data acquisition components. The sensors are used to collect the strain and / or displacement of the cantilever beam under test, and the sensors are electrically connected to the data acquisition components.

[0007] In some embodiments, the counterweight assembly includes a spatial frame, a support plate, counterweight stacks, and a protective net; the support plate is provided at the bottom of the spatial frame, multiple sets of counterweight stacks are located within the spatial frame and disposed on the support plate, adjacent sets of counterweight stacks are spaced apart, and each set of counterweight stacks includes multiple counterweight blocks stacked together; the protective net is provided around the spatial frame, and a limiting interface is provided at the top of the spatial frame, with the two side sections of the reaction beam respectively limited and connected to the corresponding limiting interface.

[0008] In some embodiments, the loading device includes a jack, a force gauge, an upper pad, and a lower pad; the force gauge is located at the top of the jack, and a plurality of upper pads are located between the force gauge and the reaction beam; a plurality of lower pads are located between the bottom of the jack and the cantilever beam under test; the loading axis of the jack passes through the loading point of the cantilever beam under test and is perpendicular to the axis of the cantilever beam under test and the axis of the reaction beam; the force gauge is electrically connected to the data acquisition component.

[0009] In some embodiments, the sensor includes a strain sensor and a displacement sensor; the strain sensor is disposed on the cantilever beam under test to detect the strain of the cantilever beam under test, and the displacement sensor is disposed on the support member with its detection end abutting against the cantilever beam under test to detect the displacement of the cantilever beam under test.

[0010] In some embodiments, the spatial frame includes a bottom frame, a top frame, columns, and diagonal braces; the top frame is located above the bottom frame, and the top frame and the bottom frame are connected by the vertically arranged columns; the bottom frame is provided with the support plate; the top frame is provided with the limiting interface in the middle; the diagonal braces are inclined and connected to the top frame and the columns; both the bottom frame and the top frame include two parallel main beams and two parallel secondary beams, the main beams and the secondary beams are arranged perpendicularly and their ends are joined to form a rectangular frame.

[0011] In some embodiments, the limiting interface is a U-shaped interface, the cross-section of which is adapted to the cross-section of the reaction beam, and the corresponding U-shaped interfaces are respectively passed through the two sides of the reaction beam.

[0012] In some embodiments, the data acquisition component includes a data acquisition instrument and an information processing terminal; both the strain sensor and the displacement sensor are electrically connected to the data acquisition instrument, and the data acquisition instrument is electrically connected to the information processing terminal.

[0013] This invention also provides a static load test method for cantilever beams of walkways, using the aforementioned static load test device for cantilever beams of walkways, comprising the following steps: controlling the loading device to preload and zero the cantilever beam under test; controlling the loading device to perform graded loading on the cantilever beam under test, maintaining the load for a certain period after reaching the load value of each grade, with the load value of the subsequent grade being greater than the load value of the previous grade; controlling the loading device to stop loading when a loading stop sign appears; and controlling the loading device to unload the cantilever beam under test in stages.

[0014] In some implementations, the loading stop indicator includes any of the following: the static load testing device malfunctions, the tested cantilever beam is damaged, the predetermined maximum load value is reached, or the final loading stage is completed.

[0015] In some embodiments, a crack observation grid line is drawn on the surface of the cantilever beam under test. The method further includes: locating and recording cracks based on the crack observation grid line during the graded loading and unloading processes.

[0016] The present invention achieves the following technical effects compared to the prior art: This invention relates to a static load testing device and method for cantilever beams of walkways. By constructing a reaction frame and establishing a closed force and information acquisition link with the loading device and data acquisition system on-site, the reaction frame forms an organized, controllable, and redundant reaction system in narrow, open spaces, providing stable support and anti-overturning capability for the loading device and limiting the counterweights. Furthermore, the axis of the reaction beam is perpendicular to the axis of the cantilever beam under test, and two sets of counterweight components are symmetrically arranged about the axis of the cantilever beam. The loading device is located at the loading point of the cantilever beam under test and is connected to both the cantilever beam and the reaction beam. The perpendicular axis ensures that the cantilever beam under test is in a stable stress state during loading, reducing additional bending moments, minimizing false displacements caused by equipment deformation, and improving the reliability of the device under stress. Furthermore, the static load test method, by employing a staged loading and unloading test process, improves the safety, load control accuracy, and reliability of monitoring results in narrow, open environments. Thus, this invention can meet the requirements of installation, calibration, zeroing, loading, and data processing of the static testing device for cantilever beam structures in confined spaces, safely and reliably detecting the stress state of cantilever beams in walkways. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a top view of a static load testing device for cantilever beams of walkways, as described in some embodiments of the present invention. Figure 2 This is a three-dimensional structural schematic diagram of a static load testing device for cantilever beams of walkways, as described in some embodiments of the present invention. Figure 3 This is a schematic diagram of the reaction frame structure in some embodiments of the present invention; Figure 4 This is a schematic diagram of the loading device in some embodiments of the present invention; Figure 5 This is a schematic diagram of the structure of a data acquisition system in some embodiments of the present invention; Figure 6 This is a diagram illustrating the on-site loading procedure for the cantilever beam under test in some embodiments of the present invention; In the diagram: 1-Reaction frame; 2-Loading device; 3-Data acquisition system; 4-Main beam; 5-Secondary beam; 6-Column; 7-Reaction beam; 8-Diagonal brace; 9-Support plate; 10-Safety net; 11-Counterweight block; 12-Upper pad; 13-Jack; 14-Force gauge; 15-Data acquisition instrument; 16-Information processing terminal; 17-Data transmission line; 18-Displacement sensor; 19-Strain sensor; 20-Lower pad; 21-Measured cantilever beam; 22-Crossbeam. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a static load testing device and method for cantilever beams of walkways, so as to solve the problems existing in the prior art and to meet the requirements of safe and reliable detection of the stress state of cantilever beams of walkways in space-constrained environments.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1 This embodiment provides a static load testing device suitable for cantilever beams of walkways, such as... Figures 1 to 5As shown, the system includes a reaction frame 1, a loading device 2, and a data acquisition system 3. The reaction frame 1 includes a reaction beam 7 and a counterweight assembly. The two sets of counterweight assemblies are symmetrically arranged about the axis of the cantilever beam 21 under test. The axis of the reaction beam 7 is perpendicular to the axis of the cantilever beam 21 under test. The middle part of the reaction beam 7 is located above the loading point of the cantilever beam 21 under test. The two side sections of the reaction beam 7 are respectively limited and connected to the two sets of counterweight assemblies. The loading device 2 abuts against the cantilever beam 21 under test and the reaction beam 7 at both ends along the loading axis. The loading axis of the loading device 2 passes through the loading point of the cantilever beam 21 under test and is perpendicular to the axis of the cantilever beam 21 under test and the axis of the reaction beam 7. The data acquisition system 3 includes a sensor and a data acquisition assembly. The sensor is used to collect the strain and / or displacement of the cantilever beam 21 under test. The sensor is electrically connected to the data acquisition assembly.

[0023] It should be noted that the reaction frame 1, loading device 2, and data acquisition system 3 of this invention form a closed force and information acquisition link on site: the reaction frame 1 provides reaction force and overall stability, the loading device 2 is responsible for applying and measuring the loading force, and the data acquisition system 3 collects, displays, and stores the deformation and strain response of the measured cantilever beam 21 in real time; the counterweight component of the reaction frame 1 is a welded steel frame steel cage structure with its bottom in contact with the ground. The reaction frame 1 is used to form an organized, controllable, and redundant reaction force system in a narrow, open site, providing stable support and anti-overturning capability for the loading device 2, and limiting the counterweight; the arrangement of the reaction frame 1 and the loading device 2 can ensure that the measured cantilever beam 21 is in a stable stress state during the loading process, reduce additional bending moment, reduce false displacement caused by equipment deformation, and improve the stress reliability of the device; it can meet the requirements of installation, calibration, loading, and data processing of the static testing device for the cantilever beam structure of the walkway in a space-constrained environment, and safely and reliably detect the stress state of the cantilever beam of the walkway.

[0024] In some implementations, such as Figure 2 and Figure 3As shown, the counterweight assembly includes a spatial frame, a support plate 9, counterweight stacks, and a protective net 10. The bottom of the spatial frame is provided with a support plate 9, and multiple sets of counterweight stacks are located inside the spatial frame and on the support plate 9. The adjacent sets of counterweight stacks are spaced apart, and each set of counterweight stacks includes multiple counterweight blocks 11 stacked together. The spatial frame is surrounded by a protective net 10, and the upper part of the spatial frame is provided with a limiting interface. The two sides of the reaction beam 7 are respectively limited and connected to the corresponding limiting interface. The reaction beam 7 of this invention is installed within the limiting interface to suppress displacement and overturning and to achieve reaction force distribution; the support plate 9 is set inside the frame as a support and distribution component for the counterweight block 11, and the support plate 9 can be made of steel plate or steel grating structure; the counterweight block 11 is a concrete counterweight block, and the counterweight block 11 is placed on the support plate 9 according to the principle of stacking and layering, with a gap reserved between adjacent stacks to reduce the risk of arching effect. During loading and unloading, it should be handled gently to avoid impact vibration causing amplification of gravity load; after the counterweight is completed, the protective net 10 is installed. The protective net 10 can be made of wire mesh, steel plate mesh or rigid enclosure mesh. The stability of the reaction frame 1 and the closed state of the protective net 10 are checked. After confirming that the test requirements are met, it is placed in the loading device 2.

[0025] In some implementations, such as Figure 4 As shown, the loading device 2 includes a jack 13, a force gauge 14, an upper pad 12, and a lower pad 20. The top of the jack 13 is equipped with a force gauge 14, and several upper pads 12 are provided between the force gauge 14 and the reaction beam 7. Several lower pads 20 are provided between the bottom of the jack 13 and the cantilever beam 21 to be measured. The loading axis of the jack 13 passes through the loading point of the cantilever beam 21 to be measured and is perpendicular to the axis of the cantilever beam 21 to be measured and the axis of the reaction beam 7. The force gauge 14 is electrically connected to the data acquisition component. In this invention, the loading device 2, the pad, the jack 13, and the force gauge 14 are connected in series. By replacing or stacking the pad, the height and coaxial fine adjustment can be achieved, so that the top of the loading device 2 contacts the lower side of the reaction beam 7 to form a closed force circuit. The jack 13 is set at the loading point of the cantilever beam 21 being measured. The loading contact component can be a loading head or a pressure block. The lower pad 20 is arranged on the lower side of the jack 13, and the force gauge 14 is set above the jack 13 along the loading direction for real-time measurement of the loading force. The upper pad 12 is set above the force gauge 14 for bearing pressure, leveling, and distributing local compressive stress. The upper pad 12 contacts the reaction beam 7 to form a reaction circuit, so that the reaction force generated when the jack 13 is lifted is transmitted to the counterweight assembly of the reaction frame 1 through the force gauge 14, the upper pad 12, and the reaction beam 7.

[0026] In some implementations, such as Figure 5As shown, the sensor includes a strain sensor 19 and a displacement sensor 18. The strain sensor 19 is installed on the cantilever beam 21 under test to detect the strain of the cantilever beam 21. The displacement sensor 18 is installed on the supporting member, and its detection end abuts against the cantilever beam 21 under test to detect the displacement of the cantilever beam 21. The strain sensor 19 of this invention adopts the form of a bonded strain gauge / strain gauge and is arranged on the critical section or crack-sensitive area of ​​the cantilever beam 21 under test. Before bonding, the concrete surface is ground, cleaned, and dried. After bonding, the lead wire and sensor are protected and encapsulated. The displacement sensor 18 is used to collect the deflection / displacement response of the loading point or control section. It can be fixed to the steel pipe supporting member by a magnetic base. The magnetic fixing method usually requires the pre-erectation of a stable scaffolding platform to provide installation and observation conditions and to ensure the rigidity and stability of the sensor mounting base.

[0027] In some implementations, such as Figure 2 and Figure 3 As shown, the spatial frame includes a bottom frame, a top frame, columns 6, and diagonal braces 8. The top frame is located above the bottom frame, and the top frame and bottom frame are connected by vertically arranged columns 6. A support plate 9 is provided on the bottom frame. A limiting interface is provided in the middle of the top frame. The diagonal braces 8 are inclined and connected to the top frame and columns 6. Both the bottom frame and the top frame include two parallel main beams 4 and two parallel secondary beams 5. The main beams 4 and secondary beams 5 are arranged perpendicularly and their ends are joined to form a rectangular frame. In this invention, the main beams 4 and secondary beams 5 are welded to form the bottom frame and the top frame. Columns 6 are welded at the four corners and necessary positions of the bottom frame and welded to the top frame to form an integral frame. To improve the lateral stiffness and torsional stability of the frame, diagonal braces 8 are provided between the columns 6 and the top frame. L-shaped steel plates are welded to the four sides of the loading and unloading ports of the columns 6 and the bottom frame for installing protective nets 10 and providing anti-fall restraint for counterweights 11 and small on-site tools.

[0028] In some embodiments, the limiting interface is a U-shaped interface, the cross-section of which is adapted to the cross-section of the reaction beam 7, and corresponding U-shaped interfaces are respectively inserted into the two sides of the reaction beam 7. This invention achieves stable contact between the reaction beam 7 and the counterweight assembly by welding a U-shaped limiting interface to the lower side of the crossbeam 22 in the middle of the top frame and installing the reaction beam 7. The reaction beam 7 can be an I-beam or an equivalent steel beam, used to distribute the reaction force of the loading device to the counterweight assembly of the reaction frame 1 and reduce the risk of localized pressure. The U-shaped limiting interface provided on the lower side of the middle of the top frame can suppress the displacement and overturning of the reaction beam 7 during the loading process.

[0029] In some implementations, such as Figure 5As shown, the data acquisition components include a data acquisition instrument 15 and an information processing terminal 16; strain sensor 19 and displacement sensor 18 are both electrically connected to the data acquisition instrument 15, and the data acquisition instrument 15 is electrically connected to the information processing terminal 16. The data acquisition system of the present invention is used to collect and store the strain and displacement responses of key parts of the measured cantilever beam 21 in real time. The information processing terminal 16 can be a laptop computer. The data acquisition instrument 15 is connected to the laptop computer, and the laptop computer runs acquisition software to realize real-time display, storage and export. In order to avoid interference to the loading area and ensure personnel safety, the data acquisition instrument 15 and the laptop computer should be arranged in a safe area away from the loading device 2. Signal transmission is achieved through an extended data transmission line 17, and shielding and grounding measures are used to reduce interference when necessary. The data transmission line 17 should be laid to avoid the operating area of ​​the loading device 2 and the reaction frame 1, and bundled and fixed along the safety channel. Each sensor is named and recorded, and its installation position, direction, range and zero point status are recorded.

[0030] The reaction frame 1 of this invention mainly includes a welded steel cage frame, I-beams, concrete counterweights, and a protective net 10. The welded steel cage frame structure includes main beams 4, secondary beams 5, columns 6, diagonal braces 8, crossbeams 22, support plates 9, and reaction beams 7. The diagonal braces 8 are welded in a herringbone or K-shape to increase the shear resistance of the frame. Steel plates or steel grids are overlapped on the main beams 4 and secondary beams 5 to form support plates 9. A U-shaped limiting interface is welded on the lower side of the top frame, and the I-beam reaction beams 7 are installed inside the interface. The concrete counterweights are stacked separately with gaps in the steel cage to avoid arching. L-shaped steel plates are welded on the four sides of the loading and unloading ports of the columns 6 and the bottom frame, and a protective net 10 is installed to provide anti-fall restraint for the concrete counterweights and small on-site tools.

[0031] The loading device 2 of the present invention is used to form a force channel to realize the force transmission, pressure distribution and anti-slip limit of the loading end when the jack 13 is lifted, so as to ensure the stability, safety and repeatability of the loading process. The loading device 2 can be arranged on the end of the cantilever beam 21 to be measured. The lower pad 20, jack 13, force gauge 14 and upper pad 12 are arranged from bottom to top. The loading device 2 is adjusted to an appropriate position and the number of pads is increased or decreased so that the top of the device contacts the lower side of the reaction beam 7.

[0032] The data acquisition system 3 of this invention is used to realize real-time measurement and graded control of load, and simultaneously collect response data such as displacement and strain of the cantilever beam 21 under test, establish an independent measurement benchmark, and form a traceable test record. The data acquisition system 3 mainly includes a high-precision strain sensor 19, a displacement sensor 18, a data transmission line 17, a data acquisition instrument 15, and a laptop computer. The strain sensor 19 and the displacement sensor 18 are arranged according to the design at key parts such as the root, mid-span, and end of the cantilever beam 21 under test, for real-time monitoring of stress, strain, and deflection changes of the beam. The data is transmitted to the data acquisition instrument 15 through the data transmission line 17. The data acquisition instrument 15 is connected to the computer through a data cable, and finally the collected data is synchronously transmitted and saved in real time in the computer.

[0033] Example 2 This embodiment provides a static load test method suitable for cantilever beams of walkways, such as... Figure 6 As shown, the static load testing device for cantilever beams of walkways, as described in Example 1, includes the following steps: Step S10: Control the loading device 2 to preload and zero the cantilever beam 21 under test; Step S20: Control the loading device 2 to perform graded loading on the cantilever beam 21 under test. After reaching the load value of each loading stage, maintain the load for a certain period of time. The load value of the next loading stage is greater than the load value of the previous loading stage. Step S30: When the loading stop flag appears, control the loading device 2 to stop loading; Step S40: Control the loading device 2 to unload the cantilever beam 21 under test in stages, and maintain the load for a certain period of time after reaching the unloading load value of each stage. The unloading load value of the later stage is less than the unloading load value of the previous stage.

[0034] Based on steps S10 to S40 above, it should be noted that before the test, this invention checks the stability of the reaction frame 1, the limiting state of the reaction beam 7, the coaxiality of the loading chain, and the working status of the sensors; starts the acquisition software, confirms that the signals of each channel are normal, and completes the zero-point setting; and selects a period of relatively stable temperature, vibration, and other changes for the test according to environmental conditions to reduce the influence of external environmental changes on the readings. Figure 6 The document includes a flowchart showing the correspondence between load values ​​and holding times for the pre-loading and graded loading stages, as per the loading procedure. Figure 6 Preloading requirements or preloading with a smaller load: Gradually apply to the preload level, checking for swaying of reaction frame 1, displacement of reaction beam 7, slippage of pad plate, stability of force gauge 14, and abnormal sensor signals; after unloading and returning to zero, zeroing or recording zero-point drift confirms normal system operation. Then follow the loading procedure attached. Figure 6 In the intermediate loading stages, loads are applied sequentially up to load values ​​P1, P2, ..., P.n When the i-th load P is reached i After holding t i During the loading phase, a laptop computer will collect, display, and store the data transmitted from the data acquisition instrument in real time, while simultaneously recording the readings of the force gauge 14, on-site photos and videos, and the location and changes of cracks on the crack observation grid. During each loading stage, the load should be increased smoothly to avoid impact loading. After loading stops, follow the loading procedure attached. Figure 6 Alternatively, the test plan may require graded unloading, preferably by unloading to zero in stages with the same or similar loading levels. Data from displacement sensor 18 and strain sensor 19 are collected simultaneously at each unloading stage to record the rebound process. After unloading to zero, residual displacement, residual strain, and the final state of the crack are read and recorded to form traceable test records and image data.

[0035] In some implementations, the loading stop indicator includes any of the following: the static load test device malfunctions, the tested cantilever beam 21 is damaged, the predetermined maximum load value is reached, or the final loading stage is completed.

[0036] It should be noted that the present invention determines that a stop flag has been reached and terminates further loading when any of the following conditions occur: a. The predetermined maximum load condition is reached or the final stage specified in the program diagram is completed; b. The reading of the force gauge 14 is difficult to stabilize or exhibits abnormal fluctuations; c. The data from the displacement sensor 18 or strain sensor 19 shows sudden jumps or abnormal growth rates; d. Cracks rapidly expand, penetrate, or show obvious signs of damage such as spalling or load-bearing degradation; e. The counterweight assembly, reaction beam 7, pad plate, or jack 13 experiences slippage, displacement, obvious shaking, or other safety risks. Loading is immediately stopped and the unloading step begins upon meeting any of the above stop flags.

[0037] In some embodiments, crack observation grid lines are drawn on the surface of the cantilever beam 21 under test. The method further includes: locating and recording cracks based on the crack observation grid lines during the graded loading and unloading processes. This invention involves painting and drawing grid lines in the observation area of ​​the cantilever beam 21 under test. The grid size is determined based on on-site readability and is used for locating and recording the appearance, expansion, and penetration of cracks during loading. Simultaneously, video and photographic equipment is prepared to continuously record the loading process and crack evolution.

[0038] The static load test method of the present invention includes device erection and sensor deployment, pre-loading and zeroing, loading and maintaining load acquisition in stages according to the loading procedure, unloading in stages after the stop mark is met and reading the residual response, thereby improving the safety of the test in a narrow open space, the accuracy of load control and the reliability of monitoring results.

[0039] The static load test method for cantilever beams of walkways applicable to this invention specifically includes the following steps: Step S1: Determine the target working condition for the test, and in accordance with the principle of equivalent bending moment, the design load of the cantilever beam 21 to be tested is equivalent to the concentrated force at the loading point, and generate a graded loading sequence and the holding time of each grade; Step S2: Erect the reaction frame 1, stack the concrete counterweight blocks on the pallet 9 with gaps between adjacent stacks, and install the reaction beam 7 so that it forms a stable reaction force contact with the counterweight components of the reaction frame 1. Step S3: Arrange the loading device 2 so that the jack 13 and the force gauge 14 are connected in series and located between the reaction beam 7 and the cantilever beam 21 being measured. The height and the loading axis are finely adjusted by replacing or stacking shims. Step S4: Attach strain sensor 19 and arrange displacement sensor 18, connect them to data acquisition instrument 15 via data transmission line 17, and connect data acquisition instrument 15 to laptop computer to complete channel naming and real-time acquisition preparation. Step S5: Perform preloading and zero the instrument to confirm that the counterweight assembly, reaction beam 7 and loading device 2 are in normal condition; Step S6: Implement graded loading and load maintenance according to the loading procedure. The data acquisition system 3 collects displacement and strain data in real time, records on-site images, and observes crack development. Step S7: Terminate loading when the stop flag appears; Step S8: Unload to zero according to the preset program and read the residual displacement, residual strain and final crack state.

[0040] The beneficial effects of this invention on the static load testing device and method for cantilever beams of walkways are as follows: This invention uses a steel cage reaction frame to bear and limit the counterweight, which meets the requirements of high difficulty in on-site load testing, the need for safety first, and real-time observation of stability. When the cantilever beam structure of the walkway shows signs of yielding, obvious deformation, local instability, or crack development, it can quickly identify and implement a load-stopping strategy, significantly improving on-site safety and reducing the risk of test interruption and accidents.

[0041] The modular steel cage reaction frame, standardized counterweight 11, and detachable reaction beam 7 and loading device 2 of the present invention can reduce on-site temporary assembly, repeated adjustments and uncontrollable trial and error process, and effectively improve the efficiency of test organization.

[0042] The present invention provides high measurement reliability. The jack 13 lifts the load and connects it in series with the force gauge 14 to form a readable and recordable load chain. At the same time, the load level can be stably reached and maintained according to the graded loading procedure, avoiding data distortion caused by experience-based judgment, and improving the accuracy and traceability of load control.

[0043] The reaction channel of the present invention forms reliable contact and limit with the steel frame, reducing the probability of local buckling, crushing or overturning of the top frame or reaction beam 7, while controlling the centering of the loading axis, reducing the additional bending moment, reducing the false displacement caused by equipment deformation, and improving the stress reliability of the device.

[0044] The test device of the present invention is simple to operate and easy to use. The same device can cover different cantilever beam interfaces, different exposed lengths, different working platform widths and other environments, and has broad application prospects in testing the load-bearing capacity of cantilever components.

[0045] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A static load testing device suitable for cantilever beams of walkways, characterized in that, include: The reaction frame includes a reaction beam and a counterweight assembly. Two sets of the counterweight assembly are symmetrically arranged about the axis of the cantilever beam under test. The axis of the reaction beam is perpendicular to the axis of the cantilever beam under test. The middle part of the reaction beam is located above the loading point of the cantilever beam under test. The two side sections of the reaction beam are respectively limited and connected to the two sets of the counterweight assembly. A loading device is provided, wherein the two ends of the loading axis of the loading device abut against the cantilever beam under test and the reaction beam respectively, and the loading axis of the loading device passes through the loading point of the cantilever beam under test and is perpendicular to the axis of the cantilever beam under test and the axis of the reaction beam. A data acquisition system, comprising sensors and a data acquisition component, wherein the sensors are used to acquire the strain and / or displacement of the cantilever beam under test, and the sensors are electrically connected to the data acquisition component.

2. The static load testing device for cantilever beams of walkways according to claim 1, characterized in that, The counterweight assembly includes a space frame, a support plate, a counterweight stack, and a protective net; The bottom of the spatial frame is provided with the support plate, and multiple sets of counterweight stacks are located within the spatial frame and disposed on the support plate. Adjacent sets of counterweight stacks are spaced apart, and each set of counterweight stacks includes multiple counterweight blocks stacked together. The space frame is surrounded by a protective net, and the upper part of the space frame is provided with a limiting interface. The two sides of the reaction beam are respectively limited and connected to the corresponding limiting interfaces.

3. The static load testing device for cantilever beams of walkways according to claim 1, characterized in that, The loading device includes a jack, a force gauge, an upper pad, and a lower pad; The jack is equipped with a force gauge at its top, and a number of upper pads are provided between the force gauge and the reaction beam. The jack is also equipped with a number of lower pads between its bottom and the cantilever beam being measured. The loading axis of the jack passes through the loading point of the cantilever beam under test and is perpendicular to the axis of the cantilever beam under test and the axis of the reaction beam; the force gauge is electrically connected to the data acquisition component.

4. The static load testing device for cantilever beams of walkways according to claim 1, characterized in that, The sensors include strain sensors and displacement sensors; The strain sensor is installed on the cantilever beam under test to detect the strain of the cantilever beam under test, and the displacement sensor is installed on the support member with its detection end abutting against the cantilever beam under test to detect the displacement of the cantilever beam under test.

5. The static load testing device for cantilever beams of walkways according to claim 2, characterized in that, The spatial frame includes a bottom frame, a top frame, columns, and diagonal braces; The top frame is located above the bottom frame, and the top frame and the bottom frame are connected by a vertically arranged column; the bottom frame is provided with a support plate; the top frame is provided with a limiting interface in the middle; the diagonal brace is inclined and connected to the top frame and the column; Both the bottom frame and the top frame include two parallel main beams and two parallel secondary beams. The main beams and the secondary beams are arranged perpendicularly and their ends are joined together to form a rectangular frame.

6. The static load testing device for cantilever beams of walkways according to claim 2, characterized in that, The limiting interface is a U-shaped interface, the cross section of which is adapted to the cross section of the reaction beam, and the corresponding U-shaped interfaces are respectively inserted into the two sides of the reaction beam.

7. The static load testing device for cantilever beams of walkways according to claim 4, characterized in that, The data acquisition component includes a data acquisition instrument and an information processing terminal; Both the strain sensor and the displacement sensor are electrically connected to the data acquisition instrument, which is electrically connected to the information processing terminal.

8. A static load test method suitable for cantilever beams of trestle walkways, characterized in that, The static load testing apparatus for cantilever beams of walkways, as described in any one of claims 1-7, comprises the following steps: The loading device is controlled to preload and zero-adjust the cantilever beam under test. The loading device is controlled to perform graded loading on the cantilever beam under test. After reaching the load value of each loading stage, the load is maintained for a certain period of time. The load value of the next loading stage is greater than the load value of the previous loading stage. When a loading stop flag appears, control the loading device to stop loading; The loading device is controlled to unload the cantilever beam under test in stages.

9. The static load test method for cantilever beams of trestle walkways according to claim 8, characterized in that, The loading stop flag includes any of the following: The static load testing device malfunctions, the tested cantilever beam is damaged, the predetermined maximum load value is reached, or the final loading stage is completed.

10. The static load test method for cantilever beams of trestle walkways according to claim 8, characterized in that, The method further includes drawing crack observation grid lines on the surface of the cantilever beam under test, and the method also includes: During the graded loading and graded unloading processes, the cracks are located and recorded based on the crack observation grid lines.

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