Quasi-static test device and method for concrete column in reinforced loading state

Abstract

The invention discloses a pseudo-static test device and method for a concrete column in a reinforced loading state, and belongs to the technical field of building construction, and the pseudo-static test device comprises a substrate on which a counter-force seat is poured; the two supporting frames are arranged on the base plate and are provided with counter-force beams; the ground beam is mounted on the base plate; the primary loading mechanism comprises an upper holding and carrying plate, a lower holding and carrying plate and a vertical jack, the lower holding and carrying plate is arranged in a hole channel of the ground beam in a penetrating manner, the upper holding and carrying plate is arranged on a to-be-tested structural column, an opposite-pull screw rod is mounted between the upper holding and carrying plate and the lower holding and carrying plate, and the vertical jack is supported on the counter-force beam and the upper holding and carrying plate; the secondary loading mechanism comprises a horizontal jack, a locking assembly and a sliding seat cushioned between the vertical jack and the counter-force beam, the locking assembly is installed on the to-be-tested structural column, and the horizontal jack is hinged to the counter-force seat and the locking assembly; the pressure sensor, the displacement sensor and the strain sensor are installed on the primary loading mechanism. The device solves the problem that most of existing pseudo-static test devices do not consider the influence of secondary stress of a reinforcing material.

Description

Technical Field

[0001] The present invention relates to the technical field of building construction, and in particular to a quasi-static test device and method for concrete columns in a reinforced load-bearing state. Background Art

[0002] Under earthquake loads, reinforced concrete vertical components can fall short of their required bearing capacity due to factors such as material aging, corrosion from harmful substances, accidental loading, or changes in their functional use, making them susceptible to brittle failure. Therefore, research into effective reinforcement materials, technologies, and methods for reinforced concrete vertical components with insufficient bearing capacity is crucial for mitigating earthquake damage, preventing casualties, and minimizing economic losses.

[0003] When reinforcing existing structures or components, it's difficult to completely unload existing components (especially vertically loaded ones). As the load on the reinforced component increases, the reinforced layer begins to experience stress, a state known as secondary stress. At this point, the strain on the reinforced layer's cross section lags behind the strain on the original component, potentially reducing the utilization rate of the reinforcement material. Therefore, studying the impact of secondary stress on the mechanical properties of reinforced components is crucial for reinforcement design and performance evaluation.

[0004] When developing new reinforcement materials and methods, pseudo-static testing is an important method for studying the seismic performance of concrete structures. However, most existing pseudo-static testing devices do not consider the effects of secondary loading on the reinforcement material. Therefore, it is urgent to design a loading device suitable for pseudo-static testing to investigate the influence of parameters such as initial load and load holding time on the seismic performance of reinforced components and to quantify the strain hysteresis effect of the secondary loading reinforcement layer. Summary of the Invention

[0005] In order to overcome the defects of the existing technology, a pseudo-static test device and method for concrete columns under reinforced loading state are provided to solve the problem that most existing structural pseudo-static test devices do not consider the influence of secondary stress on the reinforcement material.

[0006] To achieve the above purpose, a quasi-static test device for concrete columns under reinforced loading is provided, comprising: A base plate, one end of which is cast with a reaction seat; Two supporting frames arranged opposite to each other, the supporting frames being mounted on the base plate, and reaction beams being mounted on the two supporting frames; A ground beam for mounting the structural column to be tested is mounted on the base plate, the ground beam is arranged below the reaction beam, and a through-hole is formed at the bottom of the ground beam; A primary loading mechanism includes an upper holding plate, a lower holding plate, and a vertical jack. The lower holding plate is inserted into the hole, the upper holding plate is arranged on the top of the structural column to be tested, a tension screw is detachably installed between the upper holding plate and the lower holding plate, and the vertical jack is supported between the reaction beam and the upper holding plate; A secondary loading mechanism, comprising a horizontal jack, a locking assembly, and a sliding seat provided between the vertical jack and the reaction beam, wherein the locking assembly is mounted on the structural column to be tested, and the horizontal jack is hingedly connected to the reaction seat and the locking assembly; A pressure sensor for collecting the pressure value of the structural column to be measured, installed on the vertical jack; A displacement sensor for collecting the displacement value of the upper supporting plate is installed on the ground beam; The strain sensor is installed on the tension screw.

[0007] Furthermore, the support frame is a portal frame, and both ends of the reaction beam are connected to the cross beams of the two portal frames.

[0008] Furthermore, the base plate is installed with multiple anchor rods, and the anchor rods are respectively provided on opposite sides of the end of the ground beam. The anchor rods on opposite sides of the end of the ground beam are detachably installed with pressure beams, and the pressure beams are pressed against the end of the ground beam.

[0009] Furthermore, the sliding seat includes an upper pad, a lower pad and multiple rollers, the upper pad is attached to the bottom of the reaction beam, the lower pad is arranged on the vertical jack, and the multiple rollers are rotatably arranged between the upper pad and the lower pad.

[0010] Furthermore, the locking assembly includes two clamping plates, which are mounted on the structural column to be tested, and a tie rod is detachably connected between the ends of the two clamping plates.

[0011] Furthermore, the horizontal jack has a fixed end and a telescopic end, and the fixed end and the telescopic end are hinged to the reaction seat and a clamping plate respectively through ear plates.

[0012] The present invention provides a test method for a pseudo-static test device for concrete columns under a reinforced load-bearing state, comprising the following steps: Install the primary loading mechanism on the structural column to be tested on the ground beam; Applying a load to the structural column to be tested by the vertical jack of the primary loading mechanism, and collecting the pressure value of the structural column to be tested by a pressure sensor; After the pressure value of the structural column to be tested reaches a preset value, the vertical jack loading is stopped, and the tension screw of the primary loading mechanism is installed between the upper holding plate and the lower holding plate, so that the load is applied by the tension screw; Performing reinforcement construction on the structural column to be tested by increasing the cross section method to simulate the stress conditions of the concrete column in the actual reinforcement project; After the reinforcement construction and curing, the load is transferred to the vertical jacks again, and the vertical tension screws are removed at the same time; Installing a secondary loading structure between the structure to be tested and the reaction seat; The static test is simulated by the telescopic action of the horizontal jack.

[0013] The beneficial effect of the present invention is that the quasi-static test device for concrete columns under reinforced load state of the present invention can provide a constant vertical load to the test piece during the construction of the reinforcement layer to simulate the stress conditions of concrete column components in actual reinforcement projects, and facilitate the implementation of low-cycle reciprocating loads, thereby further improving the reliability of the quasi-static test.

[0014] The present invention's quasi-static testing device for concrete columns under reinforced loading conditions has a simple structure, easy operation, and a wide range of applications. The single-time loading structure of the present invention's quasi-static testing device for concrete columns under reinforced loading conditions can be used to load multiple specimens. The loaded specimens can be hoisted, transported, and moved without occupying a loading test site. While the specimens are loaded, the loads applied to the specimens can be observed and stabilized in real time, and the specimens can also be manipulated to meet various testing requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 Schematic diagram of the structure of a quasi-static test device for concrete columns under reinforced loading conditions according to an embodiment of the present invention.

[0016] Figure 2 Schematic diagram of a single loading operation of a quasi-static test device for concrete columns under a reinforced load-bearing state according to an embodiment of the present invention.

[0017] Figure 3 Schematic diagram of secondary loading of a pseudo-static test device for concrete columns under a reinforced load-bearing state according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the relevant invention and are not intended to limit the invention. It should also be noted that, for ease of description, only portions relevant to the invention are shown in the accompanying drawings.

[0019] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] Reference Figures 1 to 3 As shown, the present invention provides a quasi-static test device for concrete columns under reinforced loading state, including: a base plate 1, a support frame 2, a ground beam 3, a primary loading mechanism 4, a secondary loading mechanism 5, a pressure sensor 6, a displacement sensor 7, and a strain sensor 8.

[0021] A reaction seat 11 is cast at one end of the base plate 1 .

[0022] The two support frames 2 are arranged opposite to each other. The support frames 2 are mounted on the base plate 1. The two support frames 2 are mounted with reaction beams 21.

[0023] The ground beam 3 is used to install the structural column 9 to be tested. The ground beam 3 is installed on the base plate 1. The ground beam 3 is arranged below the reaction beam 21. The bottom of the ground beam 3 is formed with a through hole.

[0024] The primary loading mechanism 4 comprises an upper holding plate 41, a lower holding plate 42, and a vertical jack 43. The lower holding plate 42 is inserted into the hole. The upper holding plate 41 is mounted on the top of the structural column 9 to be tested. A tension screw 44 is removably mounted between the upper and lower holding plates 41, 42. The vertical jack 43 is supported between the reaction beam 21 and the upper holding plate 41.

[0025] The secondary loading mechanism 5 includes a horizontal jack 51, a locking assembly 52, and a sliding seat 53 placed between the vertical jack 43 and the reaction beam 21. The locking assembly 52 is installed on the structural column to be tested 9. The horizontal jack 51 is hingedly connected to the reaction seat 11 and the locking assembly 52.

[0026] The pressure sensor 6 is installed on the vertical jack 43. The pressure sensor 6 is used to collect the pressure value of the structural column 9 to be measured.

[0027] The displacement sensor 7 is installed on the ground beam 3. The displacement sensor 7 is used to collect the displacement value of the upper supporting plate 41. The displacement sensor is a magnetic displacement meter.

[0028] The strain sensor 8 is installed on the tension screw 44. The strain sensor is a fiber Bragg grating strain sensor.

[0029] As a preferred embodiment, the support frame 2 is a portal frame. Both ends of the reaction beam 21 are connected to the cross beams of the two portal frames.

[0030] The test piece is divided into the structural column to be tested and the ground beam. A hole is left on the bottom surface of the ground beam for installing the lower supporting plate and the lower rigid pad.

[0031] The base plate 1 is equipped with multiple anchor rods. Anchor rods are respectively provided on opposite sides of the end of the ground beam 3. Pressure beams are detachably mounted on the anchor rods on opposite sides of the end of the ground beam 3. The pressure beams press against the end of the ground beam 3.

[0032] See Figure 1 As shown, the sliding seat 53 includes an upper pad 531, a lower pad 531 and a plurality of rollers 533. The upper pad is attached to the bottom of the reaction beam 21. The lower pad is arranged on the vertical jack 43. The plurality of rollers are rotatably arranged between the upper pad and the lower pad.

[0033] See Figure 3 As shown, the locking assembly 52 includes two clamping plates 521. The two clamping plates 521 are mounted on the structural column 9 to be tested. A tie rod is detachably connected between the ends of the two clamping plates 521.

[0034] The horizontal jack 51 has a fixed end and a telescopic end, which are respectively hinged to the reaction seat 11 and a clamping plate 521 through ear plates 511.

[0035] A rigid pad is placed on the top surface of the structural column to be measured. A magnetic displacement meter is installed between the rigid pad and the ground beam.

[0036] The pressure sensor is coaxial with the structural column to be measured and is fixed on a rigid gasket.

[0037] The upper rigid pad is coaxial with the structural column to be measured and is placed on the pressure sensor. The upper rigid pad and the lower rigid pad are connected by four tension screws.

[0038] The tie rods consist of high-strength threaded rods connected by high-strength joint nuts. Combination anti-slip nuts are installed above and below the upper and lower support plates, respectively. These nuts consist of an anti-slip nut, a holding nut, and a washer. The upper and lower ends of the tie rods must not extend beyond the upper surface of the upper rigid spacer or the bottom surface of the ground beam.

[0039] The fiber Bragg grating strain sensor is attached to the surface of the high-strength screw. The magnetic displacement meter is installed between the rigid spacer and the top surface of the test piece's ground beam. The strain and deformation data can be collected and recorded by the data acquisition instrument.

[0040] The vertical jack is connected to a hydraulic oil pump through a high-pressure hose.

[0041] The reaction seat is built directly on the base plate and adopts reinforced concrete structure.

[0042] The ground beam of the specimen is fixed to the base plate through pressure beams and anchor rods. The pressure beam and base plate are connected by anchor rods (bolts) and can be disassembled and adjusted.

[0043] The horizontal jack and the reaction seat are hingedly connected. The horizontal jack is hingedly connected to the locking assembly at the end of the structural column to be tested, and the locking assembly consists of a clamping plate with a hinged joint, a clamping plate and a tie rod.

[0044] The vertical jack is connected to the reaction beam through a sliding seat.

[0045] The hydraulic oil pump is connected to the vertical jack through a high-pressure hose to apply oil pressure.

[0046] The present invention provides a test method for a pseudo-static test device for concrete columns under a reinforced load-bearing state, comprising the following steps: S1. Install the primary loading mechanism 4 on the structural column 9 to be tested on the ground beam 3.

[0047] S2 . A load is applied to the structural column 9 to be measured by the vertical jack 43 of the primary loading mechanism 4 , and the pressure sensor 6 collects the pressure value of the structural column 9 to be measured.

[0048] S3. After the pressure value of the structural column 9 to be tested reaches the preset value, the loading of the vertical jack 43 is stopped, and the tension screw 44 of the primary loading mechanism 4 is installed between the upper holding plate 41 and the lower holding plate 42, so that the load is applied by the tension screw 44.

[0049] S4. Performing reinforcement construction on the structural column 9 to be measured by increasing the cross section method to simulate the stress condition of the concrete column in the actual reinforcement project.

[0050] S5. After the reinforcement construction and maintenance, the load is transferred to the vertical jack construction again, and the vertical tension screw 44 is dismantled at the same time.

[0051] S6. Install the secondary loading structure between the structure to be tested and the reaction seat 11.

[0052] S7. Simulate a static test by extending and retracting the horizontal jack 51.

[0053] Specifically, during testing, the test method of the quasi-static test device for concrete columns under reinforced loading conditions of the present invention installs the lower supporting plate and the lower rigid pad in the channel of the reinforced concrete ground beam, and installs the rigid gasket, pressure sensor, upper supporting plate and upper rigid pad in sequence from bottom to top and with the axis aligned on the upper surface of the structural column to be tested.

[0054] The upper holding plate and the lower holding plate are connected by a tension screw rod, and both ends of the tension screw rod are fixed by a combined anti-slip nut.

[0055] A fiber Bragg grating strain sensor is installed on the high-strength screw of the tension screw, and a magnetic displacement meter is set up between the rigid gasket and the upper surface of the test piece's ground beam.

[0056] The upper rigid pad is placed in the center of the vertical jack. The ground beam is fixed to the base plate using pressure beams and anchor rods.

[0057] A load is applied to the structural column under test using a vertical jack, while the applied load is monitored by a pressure sensor. Loading is stopped after reaching the preset load value and maintained stable. After 0.5 to 1 hour, the combined anti-slip nut is tightened, and the load is applied to the tension screw. During this process, fiber Bragg grating strain sensors, pressure sensors, and magnetic displacement meters are used to observe the strain of the tension screw, the pressure value applied to the specimen, and the vertical deformation. The stress distribution changes smoothly and evenly, and the deformation of the structural column under test is not excessive.

[0058] After the entire load is borne by the tensioning screws, the vertical jack is slowly unloaded by operating the hydraulic oil pump. During this process, the values ​​of the pressure sensor and fiber grating strain sensor are constantly monitored, and the combined anti-slip nuts are adjusted as appropriate to ensure that the load on the structural column under test remains constant until the vertical jack is released from the upper rigid pad. The pressure beam and anchor rods are removed, and the adjustable load holding module in the loaded state is removed. Another adjustable load holding module can then be placed in order to perform the next loading operation.

[0059] After moving the structural column under load to a suitable testing site, it was reinforced using the cross-section enlargement method to simulate the stress conditions experienced by concrete columns in actual reinforcement projects. During the reinforcement and curing period, fiber Bragg grating strain sensors, pressure sensors, and magnetic displacement meters were used to monitor the load and vertical deformation of the tensioning screws and specimens. The combined anti-slip nuts were adjusted as appropriate to maintain stable stress on the structural column.

[0060] After reinforcement and maintenance are complete, the column to be tested is reinstalled in the primary loading mechanism, and a compression beam and anchor rods are installed to secure the specimen. A load is applied to the specimen using a vertical jack while the combined anti-slip nuts are loosened. During this process, the pressure sensor readings are constantly monitored to ensure a stable load. Once the combined anti-slip nuts are fully loosened, the high-strength joint nuts are removed to disassemble the tensioning screws. A horizontal jack is hinged to the reaction seat, and the other end is connected to the column to be tested via a locking assembly. After setting up the connection and collection instrumentation based on data collection requirements, a pseudo-static test can be performed.

[0061] In this embodiment, the test piece is cast in one step. The strength and rigidity of the ground beam should meet the test requirements, and the size of the bottom installation groove should meet the requirements for installing the lower support plate and the lower rigid pad.

[0062] The quasi-static test device for concrete columns under reinforced load conditions of the present invention can provide a constant vertical load to the specimen during the construction of the reinforcement layer to simulate the stress conditions of concrete column components in actual reinforcement projects, and facilitate the implementation of low-cycle reciprocating loads, further improving the reliability of the quasi-static test.

[0063] The present invention's quasi-static testing device for concrete columns under reinforced loading conditions has a simple structure, easy operation, and a wide range of applications. The single-time loading structure of the present invention's quasi-static testing device for concrete columns under reinforced loading conditions can be used to load multiple specimens. The loaded specimens can be hoisted, transported, and moved without occupying a loading test site. While the specimens are loaded, the loads applied to the specimens can be observed and stabilized in real time, and the specimens can also be manipulated to meet various testing requirements.

[0064] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention herein is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features having similar functions disclosed in this application.

Claims

1. A quasi-static test device for concrete columns under reinforced loading conditions, characterized in that: include: A base plate, one end of which is cast with a reaction seat; Two supporting frames arranged opposite to each other, the supporting frames being mounted on the base plate, and reaction beams being mounted on the two supporting frames; A ground beam for mounting the structural column to be tested is mounted on the base plate, the ground beam is arranged below the reaction beam, and a through-hole is formed at the bottom of the ground beam; A primary loading mechanism includes an upper holding plate, a lower holding plate, and a vertical jack. The lower holding plate is inserted into the hole, the upper holding plate is arranged on the top of the structural column to be tested, a tension screw is detachably installed between the upper holding plate and the lower holding plate, and the vertical jack is supported between the reaction beam and the upper holding plate; A secondary loading mechanism, comprising a horizontal jack, a locking assembly, and a sliding seat provided between the vertical jack and the reaction beam, wherein the locking assembly is mounted on the structural column to be tested, and the horizontal jack is hingedly connected to the reaction seat and the locking assembly; A pressure sensor for collecting the pressure value of the structural column to be measured, installed on the vertical jack; A displacement sensor for collecting the displacement value of the upper supporting plate is installed on the ground beam; The strain sensor is installed on the tension screw.

2. The quasi-static test device for concrete columns under reinforced loading conditions according to claim 1 is characterized in that: The supporting frame is a portal frame, and both ends of the reaction beam are connected to the cross beams of the two portal frames.

3. The quasi-static test device for concrete columns under reinforced loading conditions according to claim 1 is characterized in that: The base plate is installed with multiple anchor rods, and the anchor rods are respectively provided on opposite sides of the end of the ground beam. The anchor rods on opposite sides of the end of the ground beam are detachably installed with pressure beams, and the pressure beams press against the end of the ground beam.

4. The quasi-static test device for concrete columns under reinforced loading conditions according to claim 1 is characterized in that: The sliding seat includes an upper pad, a lower pad and a plurality of rollers, the upper pad is attached to the bottom of the reaction beam, the lower pad is arranged on the vertical jack, and the plurality of rollers are rotatably arranged between the upper pad and the lower pad.

5. The quasi-static test device for concrete columns under reinforced loading state according to claim 1 is characterized in that: The locking assembly includes two clamping plates, which are mounted on the structural column to be tested. A tie rod is detachably connected between the ends of the two clamping plates.

6. The quasi-static test device for concrete columns under reinforced loading conditions according to claim 5 is characterized in that: The horizontal jack has a fixed end and a telescopic end, and the fixed end and the telescopic end are hinged to the reaction seat and a clamping plate respectively through ear plates.

7. A test method for a pseudo-static test device for concrete columns under reinforced loading conditions according to any one of claims 1 to 6, characterized in that: The following steps are involved: Install the primary loading mechanism on the structural column to be tested on the ground beam; Applying a load to the structural column to be tested by the vertical jack of the primary loading mechanism, and collecting the pressure value of the structural column to be tested by a pressure sensor; After the pressure value of the structural column to be tested reaches a preset value, the vertical jack loading is stopped, and the tension screw of the primary loading mechanism is installed between the upper holding plate and the lower holding plate, so that the load is applied by the tension screw; Performing reinforcement construction on the structural column to be tested by increasing the cross section method to simulate the stress conditions of the concrete column in the actual reinforcement project; After the reinforcement construction and curing, the load is transferred to the vertical jacks again, and the vertical tension screws are removed at the same time; Installing a secondary loading structure between the structure to be tested and the reaction seat; The static test is simulated by the telescopic action of the horizontal jack.

Images