Hysteresis test device and method for reinforced concrete columns reinforced with corrugated steel pipes under secondary load

Abstract

The present application provides a hysteresis test device and method for reinforced concrete columns reinforced with corrugated steel pipes under secondary loads, which belongs to the technical field of hysteresis tests for reinforced concrete columns. The present invention is designed to solve the problem that existing test devices cannot reinforce damaged reinforced concrete columns under the working conditions of existing loads and then apply secondary loads, as well as in view of the problems existing in existing hysteresis test devices. Technical points: An L-shaped rigid beam is provided above the base, a test piece is provided between the L-shaped rigid beam and the base, tie rods are installed around the test piece, a corrugated steel pipe body is installed on the test piece, a follower assembly is provided on the L-shaped rigid beam, a vertical actuator is installed above the follower assembly, a first spiral jack is installed on the L-shaped rigid beam, a second spiral jack is installed on the base, and a lateral actuator is provided on the side of the L-shaped rigid beam. The present invention is used to test reinforced pier columns.

Description

Technical Field

[0001] The present invention relates to the technical field of reinforced concrete column hysteresis testing, in particular to a device and method for testing a reinforced concrete column reinforced with a corrugated steel pipe under secondary load. Background Art

[0002] With the continuous advancement of urbanization, reinforced concrete structures have been widely used in high-rise buildings, bridges, and other important projects. The impact of catastrophic loads such as earthquakes on these structures has attracted increasing attention. As an important component of a building's load-bearing structure, the hysteretic behavior of reinforced concrete columns under seismic forces is a key factor in evaluating a building's seismic performance. However, existing hysteretic testing devices for reinforced concrete columns still have some limitations.

[0003] The invention patent with publication number CN118032552A discloses a low-cycle reciprocating load test device for FRP reinforced concrete columns in complex environments. The device is provided with a main control console, a steel frame is provided on one side of the main control console, a pressing assembly is provided on the top of the inner side of the steel frame, a test box is provided below the pressing assembly, a sand supply assembly is provided on the top of the steel frame, an air blowing assembly is provided on one side of the steel frame, and a liquid supply assembly is provided inside the steel frame on one side of the test box. The above-mentioned low-cycle reciprocating load test device for FRP reinforced concrete columns under complex environments is used to test the hysteretic performance of FRP reinforced concrete columns under complex environments. However, when in use, it is not possible to study the influence of parameters such as axial compression ratio, corrugated steel pipe thickness and grouting material thickness on the failure mode of reinforced pier columns and mechanical indicators such as pier column bearing capacity, stiffness, ductility, and viscous damping coefficient; and it is not possible to study the influence of corrugation deformation energy dissipation on the energy dissipation capacity of reinforced pier columns by comparing the test results of corrugated steel pipe reinforced concrete pier columns with different corrugation sizes and plain steel pipe reinforced concrete pier columns.

[0004] Existing testing devices generally cannot perform secondary load testing: a primary load is applied to an existing reinforced concrete column, the load is maintained constant, reinforcement of the reinforced concrete column is performed, and a secondary load is applied after the reinforcement is completed. The importance of secondary loads is rarely mentioned or recognized in existing technologies. Therefore, a secondary load hysteresis test device and method for corrugated steel pipe reinforced reinforced concrete columns is urgently needed. Summary of the Invention

[0005] In order to solve the problem that the existing test device cannot reinforce the damaged reinforced concrete column under the working condition of the existing load and then apply a secondary load, and in view of the problems existing in the existing hysteresis test device, the present invention proposes a hysteresis test device and method for reinforcing reinforced concrete columns with corrugated steel pipes under secondary load.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a hysteresis test device for corrugated steel pipe reinforced concrete columns with secondary loads, comprising a base, an L-shaped rigid beam is arranged above the base, a specimen is arranged between the L-shaped rigid beam and the base, tie rods are installed around the specimen, a corrugated steel pipe body is installed on the specimen, a follow-up assembly is provided on the L-shaped rigid beam, a vertical actuator is installed above the follow-up assembly, a first spiral jack is installed on the L-shaped rigid beam, a second spiral jack is installed on the base, a lateral actuator is provided on the side of the L-shaped rigid beam, lateral LVDTs are installed on both the specimen and the corrugated steel pipe body, a longitudinal LVDT is installed on the specimen, through-type force sensors are installed around the bottom of the specimen, and a first spring is connected to the bottom of the through-type force sensor.

[0007] As a preferred solution of the present invention, the follower assembly includes a first pressure plate fixedly connected to the bottom of the vertical actuator, a first roller is provided below the first pressure plate, a second pressure plate is provided at the bottom of the first roller, the second pressure plate is fixedly connected to the L-shaped rigid beam, an extension assembly is installed on the follower assembly, a first support assembly is installed on the second spiral jack, a detection assembly is installed between the second spiral jack and the first spiral jack, a second support assembly is installed between the detection assembly and the first support assembly, a connecting assembly is installed on the second support assembly, an offset amplification assembly is connected to the connecting assembly, and a guide assembly is installed on the offset amplification assembly and the first support assembly.

[0008] As a preferred solution of the present invention, the extension assembly includes an extension plate slidably mounted on the side of the second pressure plate, shaft sleeves are equidistantly mounted on the extension plate, a second roller is arranged in the shaft sleeve, and stop blocks are fitted on the front and rear sides of the second roller, the stop blocks are fixedly connected to the extension plate, the sides of the second pressure plate and the extension plate are fixedly connected with a first connecting plate, and a docking groove for docking with the first connecting plate is provided in the extension plate.

[0009] As a preferred solution of the present invention, the first support assembly includes an outer frame fixedly connected to the second screw jack, a support block and a first hydraulic rod are installed at the bottom of the outer frame, and a connecting plate is fixedly provided on the outer frame.

[0010] As a preferred solution of the present invention, the detection component includes a base plate fixedly connected to the bottom of the first spiral jack, a connecting block is slidably installed at the bottom of the base plate, a sliding rod is fixedly provided below the connecting block, a fixed cylinder is fitted on the outer side of the sliding rod, a second spring is installed at the bottom of the sliding rod, a protrusion is fixedly provided on the second spring, a connecting ring is welded on the protrusion, the protrusion and the connecting ring are all slidably connected to the fixed cylinder, and the fixed cylinder and the second spiral jack are fixedly connected.

[0011] As a preferred solution of the present invention, the second support assembly includes a fixed block fixedly connected to the second spiral jack, a guide rod is fixedly provided on the fixed block, the guide rod passes through the interior of the protrusion, a second connecting plate is fixedly provided on the protrusion, a support frame is fixedly connected to the second connecting plate, the support frame is slidably installed on the movable plate, and the movable plate and the outer frame are slidably connected.

[0012] As a preferred solution of the present invention, the connecting assembly includes a fixing rod fixedly connected to the support frame, a key sleeve is fixedly provided on the fixing rod, a spline rod is connected to the key in the key sleeve, and an extension rod is fixedly connected to the spline rod.

[0013] As a preferred solution of the present invention, the offset amplification component includes a first rack fixedly connected to the extension rod, the side of the first rack is meshed with a first gear, the side of the first gear is meshed with a second gear, the rear side of the second gear is fixedly connected to a third gear, the side of the third gear is meshed with a second rack, the number of teeth of the first gear is greater than the number of teeth of the second gear, and the number of teeth of the first gear is the same as the number of teeth of the third gear.

[0014] As a preferred solution of the present invention, the guide assembly includes a support seat fixedly connected to the outer frame, a first guide plate fixedly connected to the first rack, a second guide plate fixedly connected to the second rack, the first guide plate and the second guide plate are both slidingly connected to the support seat, and the first gear, the second gear and the third gear are all rotatingly connected to the support seat.

[0015] The hysteresis test method for reinforced concrete columns reinforced with corrugated steel tubes under secondary loads comprises the following steps:

[0016] S1: Apply a pre-compression axial force N1 from the bottom of the first spring, and then reinforce. After the grouting material specimen under the same curing conditions reaches the design strength, a vertical force is applied to the top of the specimen using a vertical actuator and a follower assembly. The tie rod of the load-holding device is removed, and a horizontal reciprocating load is applied to the specimen using a lateral actuator.

[0017] S2: The vertical displacement of the specimen end is measured using a longitudinal LVDT, and the lateral displacement of the specimen at different heights is measured using a lateral LVDT. Embedded strain gauges are used to measure the strain of concrete and grouting materials, and resistance strain rosettes are used to measure the strain at the crests, antinodes, and troughs of the corrugated steel pipe. The embedded strain gauges and resistance strain rosettes are arranged in the same position to obtain the strain distribution of each component along the cross-sectional height.

[0018] S3: The measurement sections are located at 75mm, 225mm and 375mm from both ends of the specimen to measure the deformation of the specimen column end and the range of the plastic hinge; at each measurement section, a group of transverse and longitudinal strain gauges are arranged at the center of the concrete, 8 longitudinal strain gauges are arranged along 45° of the grouting material, and 8 groups of strain rosettes are arranged along 45° of the corrugated steel pipe; based on the test results, the hysteresis curve and skeleton curve of the reinforced concrete pier column reinforced with the corrugated steel pipe body are obtained, and the influence of parameters such as axial compression ratio, corrugated steel pipe thickness and grouting material thickness on the failure mode of the reinforced pier column and mechanical indicators such as the bearing capacity, stiffness, ductility and viscous damping coefficient of the pier column are studied; by comparing the test results of reinforced concrete pier columns reinforced with corrugated steel pipe bodies of different corrugation sizes and reinforced concrete pier columns reinforced with flat steel pipes, the influence of corrugation deformation energy dissipation on the energy dissipation capacity of the reinforced pier column is studied; the values ​​of key parameters required for finite element modeling are determined.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present application provides a secondary load corrugated steel pipe reinforced concrete column hysteresis test device and method, which belongs to the technical field of reinforced concrete column hysteresis test, and includes a base, an L-shaped rigid beam is provided above the base, a test piece is provided between the L-shaped rigid beam and the base, tie rods are installed around the test piece, a corrugated steel pipe body is installed on the test piece, a follower assembly is provided on the L-shaped rigid beam, a vertical actuator is installed above the follower assembly, a first screw jack is installed on the L-shaped rigid beam, a second screw jack is installed on the base, and a lateral actuator is provided on the side of the L-shaped rigid beam. The present application solves the problem that the existing test device cannot affect the failure mode of the reinforced pier column and the mechanical indicators such as the bearing capacity, stiffness, ductility, and viscous damping coefficient of the pier column through parameters such as axial compression ratio, corrugated steel pipe thickness, and grouting material thickness.

[0021] The test device provided by this invention implements a secondary load test: a load is first applied to an existing reinforced concrete column, the load is maintained while the reinforced concrete column is reinforced, and a secondary load is applied after the reinforcement is completed. This can simulate the mechanical properties of existing reinforced concrete piers in actual engineering projects, reinforce them under upper load conditions, and then evaluate their performance after reinforcement.

[0022] The test device of the present invention can test the effects of parameters such as axial compression ratio, corrugated steel pipe thickness, and grouting material thickness on the failure mode of reinforced pier columns (damaged reinforced concrete pier columns reinforced with corrugated steel pipes) under existing load conditions, as well as mechanical indicators such as the pier's bearing capacity, stiffness, ductility, and viscous damping coefficient. The present invention is suitable for testing reinforced pier columns.

[0023] The specific advantages are as follows:

[0024] 1. The device is equipped with a lateral actuator, a lateral LVDT, and a longitudinal LVDT. The lateral actuator is used to apply a horizontal reciprocating load to the specimen. The vertical displacement of the specimen end is measured by the longitudinal LVDT, and the lateral displacement of the specimen at different height positions is measured by the lateral LVDT. Based on the test results, the device can obtain the hysteresis curve and skeleton curve of the corrugated steel tube reinforced reinforced concrete pier column, and study the influence of parameters such as axial compression ratio, corrugated steel tube thickness, and grouting material thickness on the failure mode of the reinforced pier column and mechanical indicators such as the pier column bearing capacity, stiffness, ductility, and viscous damping coefficient; by comparing the test results of corrugated steel tube reinforced reinforced concrete pier columns with different corrugation sizes and flat steel tube reinforced reinforced concrete pier columns, the influence of corrugation deformation energy dissipation on the energy dissipation capacity of the reinforced pier column is studied, and the values ​​of key parameters required for finite element modeling are determined.

[0025] 2. Through the follow-up component on the device, when the L-shaped rigid beam moves laterally, the first roller at the bottom of the vertical actuator rolls to keep the top of the specimen always in a state of applying vertical force, ensuring the stability of the device during operation. The device is also provided with an extension component, and the installation position and number of the extension component can be increased according to the lateral movement distance of the L-shaped rigid beam, and the second roller on the extension component can always be located inside the sleeve to ensure the stability of the device during operation.

[0026] 3. Through the detection components set up, the device can detect whether the L-shaped rigid beam is deformed during the test to ensure the accuracy of the test results. When the L-shaped rigid beam is deformed, the vertical distance between the first spiral jack and the second spiral jack will change. By observing whether the downward movement distance of the sliding rods on both sides of the device changes, it can be judged whether the L-shaped rigid beam is deformed, thereby enhancing the accuracy of the device detection.

[0027] 4. The device is provided with a connecting assembly and an offset amplification assembly. When the vertical spacing between the first screw jack and the second screw jack changes, the sliding rod will drive the protrusion, the support frame, the fixing rod, the key cylinder, the spline rod, the extension rod and the first rack to move downward. When the first rack moves downward, it will drive the first gear to rotate. The rotation of the first gear drives the second gear and the third gear to rotate. When the second gear and the third gear rotate, they will drive the second rack to move downward. Since the number of teeth of the first gear is the same as the number of teeth of the third gear, and the number of teeth of the first gear is greater than the number of teeth of the second gear, when the first gear rotates, the distance the second rack moves downward is greater than the distance the first rack moves downward, so that the device can amplify the change value when the vertical spacing between the first screw jack and the second screw jack changes, which is convenient for test personnel to judge the deformation of the L-shaped rigid beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings and detailed embodiments. 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 inventive efforts. Among them:

[0029] Figure 1 This is a schematic diagram of the overall structure of the hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary loads of the present invention;

[0030] Figure 2 yes Figure 1 A magnified schematic diagram of the structure at A in the middle;

[0031] Figure 3 yes Figure 1 A magnified schematic diagram of the structure at B in the middle;

[0032] Figure 4 This is a schematic diagram of the split structure of the second roller and the sleeve of the present invention;

[0033] Figure 5 This is a schematic diagram of the disassembled structure of the first screw jack and the detection assembly of the present invention;

[0034] Figure 6 This is a schematic diagram of the split structure of the detection component and the first support component of the present invention;

[0035] Figure 7 yes Figure 6 A magnified schematic diagram of the structure at position C in the middle;

[0036] Figure 8 This is a schematic diagram of the connection structure between the detection component and the second support component of the present invention;

[0037] Figure 9 yes Figure 8 A magnified schematic diagram of the structure at D in the middle;

[0038] Figure 10 yes Figure 8 A magnified schematic diagram of the structure at E in the middle;

[0039] Figure 11 yes Figure 8 A magnified schematic diagram of the structure at F in the middle;

[0040] Figure 12 It is a schematic diagram of the disassembled structure of the second rack and the second guide plate of the present invention.

[0041] Figure numerals: 1, base; 2, L-shaped rigid beam; 3, vertical actuator; 4, follower assembly; 401, first pressure plate; 402, first roller; 403, second pressure plate; 5, extension assembly; 501, extension plate; 502, shaft sleeve; 503, second roller; 504, stopper; 505, first connecting plate; 506, docking groove; 6, first screw jack; 7, second screw jack; 8, lateral actuator; 9, test piece; 10, pull rod; 11, corrugated steel pipe body; 12, lateral LVDT; 13, longitudinal LVDT; 14, first spring; 15, through-type force sensor; 16, first support assembly; 1601, outer frame; 1602, support block; 1603, first hydraulic rod; 1604, connecting plate; 17, detection group Parts; 1701, bottom plate; 1702, connecting block; 1703, sliding rod; 1704, fixing cylinder; 1705, second spring; 1706, protrusion; 1707, connecting ring; 18, second supporting assembly; 1801, guide rod; 1802, second connecting plate; 1803, supporting frame; 1804, fixing block; 1805, movable plate; 19, connecting assembly; 1901, fixing rod; 1902, key sleeve; 1903, spline rod; 1904, extension rod; 20, offset amplification assembly; 2001, first rack; 2002, first gear; 2003, second gear; 2004, second rack; 2005, third gear; 21, guide assembly; 2101, support seat; 2102, first guide plate; 2103, second guide plate. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0043] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0044] Next, the present invention is described in detail with reference to schematic diagrams. For ease of illustration, cross-sectional views of device structures may be partially enlarged and not to scale when describing the embodiments of the present invention. Furthermore, the schematic diagrams are merely illustrative and should not limit the scope of protection of the present invention. Furthermore, in actual production, three-dimensional dimensions, including length, width, and depth, should be included.

[0045] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0046] like Figures 1-12 As shown, the hysteresis test device for corrugated steel pipe reinforced concrete column with secondary load includes a base 1, an L-shaped rigid beam 2 is arranged above the base 1, a specimen 9 is arranged between the L-shaped rigid beam 2 and the base 1, tie rods 10 are installed around the specimen 9, a corrugated steel pipe body 11 is installed on the specimen 9, a follower assembly 4 is provided on the L-shaped rigid beam 2, a vertical actuator 3 is installed above the follower assembly 4, a first spiral jack 6 is installed on the L-shaped rigid beam 2, a second spiral jack 7 is installed on the base 1, a lateral actuator 8 is arranged on the side of the L-shaped rigid beam 2, a lateral LVDT 12 is installed on both the specimen 9 and the corrugated steel pipe body 11, a longitudinal LVDT 13 is installed on the specimen 9, and through-type force sensors 15 are installed around the bottom of the specimen 9, and the bottom of the through-type force sensor 15 is connected to a first spring 14. A pre-compression axial force N1 is applied from the bottom of the first spring 14, and then reinforcement is carried out. After the grouting material specimen 9 reaches the design strength under the same curing conditions, a vertical force is applied to the top of the specimen 9 using the vertical actuator 3 and the follower assembly 4. The pull rod 10 of the load-holding device is removed, and a horizontal reciprocating load is applied to the specimen 9 using the lateral actuator 8.

[0047] The vertical displacement of the end of the specimen 9 was measured using a longitudinal LVDT 13, and the lateral displacement of the specimen 9 at different heights was measured using a lateral LVDT 12. Embedded strain gauges were used to measure the strain of the concrete and grouting material, and a resistance strain rosette was used to measure the strain at the crests, antinodes, and troughs of the corrugated steel pipe. The embedded strain gauges and the resistance strain rosette were arranged in the same position to obtain the distribution of strain of each component along the cross-sectional height.

[0048] The measurement sections are located at 75mm, 225mm and 375mm from both ends of specimen 9 to measure the deformation of the column end and the range of the plastic hinge of specimen 9; at each measurement section, a group of transverse and longitudinal strain gauges are arranged at the center of the concrete, 8 longitudinal strain gauges are arranged along 45° of the grouting material, and 8 groups of strain rosettes are arranged along 45° of the corrugated steel pipe; based on the test results, the hysteresis curve and skeleton curve of the reinforced concrete pier column reinforced with the corrugated steel pipe body 11 are obtained, and the influence of parameters such as axial compression ratio, corrugated steel pipe thickness and grouting material thickness on the failure mode of the reinforced pier column and mechanical indicators such as the bearing capacity, stiffness, ductility and viscous damping coefficient of the pier column are studied; by comparing the test results of reinforced concrete pier columns reinforced with corrugated steel pipe bodies 11 with different corrugation sizes and reinforced concrete pier columns reinforced with flat steel pipes, the influence of corrugation deformation energy dissipation on the energy dissipation capacity of the reinforced pier column is studied; and the values ​​of key parameters required for finite element modeling are determined.

[0049] In this embodiment, the follower assembly 4 includes a first pressure plate 401 fixedly connected to the bottom of the vertical actuator 3, a first roller 402 is provided below the first pressure plate 401, a second pressure plate 403 is provided at the bottom of the first roller 402, the second pressure plate 403 is fixedly connected to the L-shaped rigid beam 2, an extension assembly 5 is installed on the follower assembly 4, a first support assembly 16 is installed on the second spiral jack 7, a detection assembly 17 is installed between the second spiral jack 7 and the first spiral jack 6, a second support assembly 18 is installed between the detection assembly 17 and the first support assembly 16, a connecting assembly 19 is installed on the second support assembly 18, an offset amplification assembly 20 is connected to the connecting assembly 19, and a guide assembly 21 is installed on the offset amplification assembly 20 and the first support assembly 16. When the L-shaped rigid beam 2 moves laterally, while the first pressure plate 401 continues to press down, the L-shaped rigid beam 2 can move on the first pressure plate 401 through the first roller 402 on the second pressure plate 403, so that the device can work stably, and the detection component 17 and the offset amplification component 20 facilitate subsequent detection of whether the L-shaped rigid beam 2 is deformed.

[0050] The second roller 503 on the extension assembly 501 can be moved in the sleeve 502 at equal intervals, and the second roller 503 is provided in the sleeve 502. The front and rear sides of the second roller 503 are fitted with stoppers 504, and the stoppers 504 are fixedly connected to the extension plate 501. The second pressure plate 403 and the sides of the extension plate 501 are fixedly connected with a first connecting plate 505, and a docking groove 506 for docking with the first connecting plate 505 is provided in the extension plate 501. The device can install different numbers of extension assemblies 5 at corresponding positions of the second pressure plate 403 according to the distance the second pressure plate 403 needs to move. The second roller 503 on the extension assembly 5 can move in the sleeve 502 without affecting the normal rotation of the second roller 503, thereby ensuring the stability of the device during operation. The splicing function of multiple extension plates 501 can be achieved by installing the first connecting plate 505 into the docking groove 506.

[0051] In this embodiment, the first support assembly 16 includes an outer frame 1601 fixedly connected to the second spiral jack 7, a support block 1602 and a first hydraulic rod 1603 are installed at the bottom of the outer frame 1601, a connecting plate 1604 is fixedly provided on the outer frame 1601, and the first hydraulic rod 1603 can be extended or shortened to cooperate with the support block 1602 so that the outer frame 1601 is stably supported on all sides.

[0052] In this embodiment, the detection component 17 includes a base plate 1701 fixedly connected to the bottom of the first screw jack 6, a connecting block 1702 is slidably installed at the bottom of the base plate 1701, a slide rod 1703 is fixedly provided below the connecting block 1702, a fixed cylinder 1704 is fitted on the outer side of the slide rod 1703, a second spring 1705 is installed at the bottom of the slide rod 1703, a protrusion 1706 is fixedly provided on the second spring 1705, a connecting ring 1707 is welded on the protrusion 1706, the protrusion 1706 and the connecting ring 1707 are all slidably connected to the fixed cylinder 1704, and the fixed cylinder 1704 and the second screw jack are fixedly provided with a screw rod 1703. 7 are fixedly connected. When the vertical spacing between the first spiral jack 6 and the second spiral jack 7 changes, the slide rod 1703 can slide in the fixed tube 1704, so that the second spring 1705 is compressed, and the protrusion 1706 and the connecting ring 1707 will move downward. The first spiral jack 6 can slide in the connecting block 1702 through the bottom plate 1701, thereby adapting to the change in the horizontal spacing between the first spiral jack 6 and the second spiral jack 7. Subsequently, the height changes of the two groups of protrusions 1706 and the connecting ring 1707 can be compared to detect whether the spacing between the first spiral jack 6 and the second spiral jack 7 has changed.

[0053] In this embodiment, the second support assembly 18 includes a fixed block 1804 fixedly connected to the second spiral jack 7, a guide rod 1801 is fixedly provided on the fixed block 1804, the guide rod 1801 passes through the interior of the protrusion 1706, a second connecting plate 1802 is fixedly provided on the protrusion 1706, a support frame 1803 is fixedly connected to the second connecting plate 1802, the support frame 1803 is slidably installed on the movable plate 1805, and the movable plate 1805 is slidably connected to the outer frame 1601. The guide rod 1801 ensures that the protrusion 1706, the second connecting plate 1802 and the support frame 1803 can move vertically up and down, and the support frame 1803 can move stably up and down on the movable plate 1805.

[0054] In this embodiment, the connecting assembly 19 includes a fixed rod 1901 fixedly connected to the support frame 1803, a key sleeve 1902 is fixedly provided on the fixed rod 1901, a spline rod 1903 is keyed inside the key sleeve 1902, an extension rod 1904 is fixedly connected to the spline rod 1903, and the spline rod 1903 can slide in the key sleeve 1902, so that the support frame 1803 will not affect the deformation detection of the device when it moves laterally.

[0055] In this embodiment, the offset amplification component 20 includes a first rack 2001 fixedly connected to the extension rod 1904, the side of the first rack 2001 is meshed with the first gear 2002, the side of the first gear 2002 is meshed with the second gear 2003, the rear side of the second gear 2003 is fixedly connected to the third gear 2005, and the side of the third gear 2005 is meshed with the second rack 2004. When the extension rod 1904 moves downward, it will first drive the first rack 2001 to move downward, so that the first gear 2002 rotates, the first gear 2002 drives the second gear 2003 and the third gear 2005 to rotate synchronously, and when the third gear 2005 rotates, it drives the second rack 2004 to move. The number of teeth of the first gear 2002 is greater than the number of teeth of the second gear 2003, and the number of teeth of the first gear 2002 is the same as the number of teeth of the third gear 2005. When the first gear 2002 rotates a single circle, the moving distance of the second rack 2004 is greater than that of the first rack 2001, thereby magnifying the offset of the extension rod 1904, which is convenient for the test personnel to observe.

[0056] In this embodiment, the guide assembly 21 includes a support base 2101 fixedly connected to the outer frame 1601, a first guide plate 2102 fixedly connected to the first rack 2001, and a second guide plate 2103 fixedly connected to the second rack 2004. The first guide plate 2102 and the second guide plate 2103 are all slidably connected to the support base 2101, and the first gear 2002, the second gear 2003 and the third gear 2005 are all rotatably connected to the support base 2101. The first guide plate 2102 enables the first rack 2001 to move vertically up and down, and the second guide plate 2103 enables the second rack 2004 to move vertically up and down. Figure 11 As shown, the moving distance of the second rack 2004 can be calculated subsequently by the scale marks and triangular marks on the second guide plates 2103 on both sides.

[0057] It should be noted that the present invention is a hysteresis test device and method for corrugated steel pipe reinforced concrete columns with secondary loads. First, Figure 1 As shown, a preload axial force N1 is applied from the bottom of the first spring 14, followed by reinforcement. After the grouting material specimen 9 reaches its design strength under the same curing conditions, a vertical force is applied to the top of the specimen 9 using the vertical actuator 3 and follower assembly 4. The tie rod 10 of the load-holding device is removed, and a horizontal reciprocating load is applied to the specimen 9 using the lateral actuator 8. The vertical displacement of the end of the specimen 9 is measured using the longitudinal LVDT 13, and the lateral displacement of the specimen 9 at different heights is measured using the lateral LVDT 12. Embedded strain gauges are used to measure the strain of the concrete and grouting material, and a resistance strain rosette is used to measure the strain at the crests, antinodes, and troughs of the corrugated steel pipe. The embedded strain gauges and the resistance strain rosette are arranged in the same position to obtain the strain distribution of each component along the cross-sectional height.

[0058] The measurement sections are located at 75mm, 225mm and 375mm from both ends of specimen 9 to measure the deformation of the column end and the range of the plastic hinge of specimen 9; at each measurement section, a group of transverse and longitudinal strain gauges are arranged at the center of the concrete, 8 longitudinal strain gauges are arranged along 45° of the grouting material, and 8 groups of strain rosettes are arranged along 45° of the corrugated steel pipe; based on the test results, the hysteresis curve and skeleton curve of the reinforced concrete pier column reinforced with the corrugated steel pipe body 11 are obtained, and the influence of parameters such as axial compression ratio, corrugated steel pipe thickness and grouting material thickness on the failure mode of the reinforced pier column and mechanical indicators such as the bearing capacity, stiffness, ductility and viscous damping coefficient of the pier column are studied; by comparing the test results of reinforced concrete pier columns reinforced with corrugated steel pipe bodies 11 with different corrugation sizes and reinforced concrete pier columns reinforced with flat steel pipes, the influence of corrugation deformation energy dissipation on the energy dissipation capacity of the reinforced pier column is studied; and the values ​​of key parameters required for finite element modeling are determined.

[0059] like Figures 1-4As shown, when the L-shaped rigid beam 2 moves laterally, the L-shaped rigid beam 2 can move on the first pressure plate 401 via the first roller 402 on the second pressure plate 403, keeping the first pressure plate 401 in a continuously downwardly pressed state. By installing the first connecting plate 505 into the docking groove 506, the second pressure plate 403 and the extension assembly 5 or multiple extension plates 501 can be connected. The device can install different numbers of extension assemblies 5 at corresponding positions on the second pressure plate 403 according to the required movement distance of the second pressure plate 403. The second roller 503 on the extension assembly 5 can move within the shaft sleeve 502 without affecting the normal rotation of the second roller 503, ensuring the stability of the device during operation.

[0060] like Figure 5-Figure 12As shown, the first support assembly 16 is used to support the guide assembly 21. The first hydraulic rod 1603 can be extended or shortened, cooperating with the support block 1602 to provide stable support on all sides of the outer frame 1601. When the L-shaped rigid beam 2 deforms, the vertical spacing between the first screw jack 6 and the second screw jack 7 changes. The sliding rod 1703 slides within the fixed cylinder 1704, the second spring 1705 is compressed, and the protrusion 1706 and the connecting ring 1707 move up and down under the guidance of the guide rod 1801. The first screw jack 6 can slide within the connecting block 1702 through the bottom plate 1701, thereby adapting to the change in the horizontal spacing between the first screw jack 6 and the second screw jack 7 when the L-shaped rigid beam 2 moves laterally. The height changes of the two sets of protrusions 1706 and the connecting ring 1707 can be compared to detect whether the spacing between the first screw jack 6 and the second screw jack 7 has changed, thereby determining whether the L-shaped rigid beam 2 has deformed. The guide rod 1801 ensures that the protrusion 1706, the second connecting plate 1802 and the support frame 1803 can move vertically up and down, and the support frame 1803 can move up and down stably on the movable plate 1805. The spline rod 1903 can slide in the key sleeve 1902, so that the support frame 1803 does not affect the deformation detection device when it moves laterally. When the extension rod 1904 moves downward, it will first drive the first rack 2001 to move downward, causing the first gear 2002 to rotate. The first gear 2002 drives the second gear 2003 and the third gear 2005 to rotate synchronously. When the third gear 2005 rotates, it will drive the second rack 2004 to move. The number of teeth of the first gear 2002 is greater than the number of teeth of the second gear 2003. The number of teeth of the first gear 2002 is the same as the number of teeth of the third gear 2005. When the first gear 2002 rotates a single circle, the movement distance of the second rack 2004 is greater than the first rack 2001, thereby amplifying the offset of the extension rod 1904. The support seat 2101 is used to support the first guide plate 2102 and the second guide plate 2103. The first guide plate 2102 enables the first rack 2001 to move vertically up and down, and the second guide plate 2103 enables the second rack 2004 to move vertically up and down. Figure 11 As shown, the moving distance of the second rack 2004 can be calculated subsequently by the scale marks and triangular marks on the second guide plates 2103 on both sides, which is convenient for the test personnel to observe.

[0061] Although the present invention has been described above with reference to embodiments, various modifications may be made thereto and equivalent components may be substituted without departing from the scope of the present invention. In particular, as long as there are no structural conflicts, the various features of the embodiments disclosed herein may be combined with each other in any manner, and the omission of an exhaustive description of such combinations in this specification is solely for the sake of space and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load, comprising a base (1), characterized in that: An L-shaped rigid beam (2) is provided above the base (1), a test piece (9) is provided between the L-shaped rigid beam (2) and the base (1), a pull rod (10) is installed around the test piece (9), a corrugated steel pipe body (11) is installed on the test piece (9), a follower assembly (4) is provided on the L-shaped rigid beam (2), a vertical actuator (3) is installed above the follower assembly (4), and a first screw jack (6) is installed on the L-shaped rigid beam (2). ), a second screw jack (7) is installed on the base (1), a lateral actuator (8) is provided on the side of the L-shaped rigid beam (2), a lateral LVDT (12) is installed on the test piece (9) and the corrugated steel pipe body (11), a longitudinal LVDT (13) is installed on the test piece (9), and a through-type force sensor (15) is installed around the bottom of the test piece (9), and the bottom of the through-type force sensor (15) is connected to a first spring (14); The follower assembly (4) includes a first pressure plate (401) fixedly connected to the bottom of the vertical actuator (3), a first roller (402) is provided below the first pressure plate (401), a second pressure plate (403) is provided at the bottom of the first roller (402), the second pressure plate (403) is fixedly connected to the L-shaped rigid beam (2), an extension assembly (5) is installed on the follower assembly (4), a first support assembly (16) is installed on the second screw jack (7), a detection assembly (17) is installed between the second screw jack (7) and the first screw jack (6), a second support assembly (18) is installed between the detection assembly (17) and the first support assembly (16), a connecting assembly (19) is installed on the second support assembly (18), an offset amplification assembly (20) is connected to the connecting assembly (19), and a guide assembly (21) is installed on the offset amplification assembly (20) and the first support assembly (16).

2. The hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load according to claim 1, characterized in that: The extension assembly (5) comprises an extension plate (501) slidably mounted on the side of the second pressure plate (403), shaft sleeves (502) are equidistantly mounted on the extension plate (501), a second roller (503) is arranged in the shaft sleeve (502), and stoppers (504) are fitted on both the front and rear sides of the second roller (503), the stoppers (504) and the extension plate (501) are fixedly connected, the side surfaces of the second pressure plate (403) and the extension plate (501) are fixedly connected to a first connecting plate (505), and a docking groove (506) for docking with the first connecting plate (505) is provided in the extension plate (501).

3. The hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load according to claim 1, characterized in that: The first support assembly (16) comprises an outer frame (1601) fixedly connected to the second screw jack (7), a support block (1602) and a first hydraulic rod (1603) are mounted on the bottom of the outer frame (1601), and a connecting plate (1604) is fixedly provided on the outer frame (1601).

4. The hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load according to claim 3, characterized in that: The detection component (17) includes a base plate (1701) fixedly connected to the bottom of the first spiral jack (6), a connecting block (1702) is slidably installed at the bottom of the base plate (1701), a sliding rod (1703) is fixedly installed below the connecting block (1702), a fixed cylinder (1704) is fitted on the outer side of the sliding rod (1703), a second spring (1705) is installed at the bottom of the sliding rod (1703), a protrusion (1706) is fixedly installed on the second spring (1705), a connecting ring (1707) is welded on the protrusion (1706), the protrusion (1706) and the connecting ring (1707) are both slidably connected to the fixed cylinder (1704), and the fixed cylinder (1704) and the second spiral jack (7) are fixedly connected.

5. The hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load according to claim 4, characterized in that: The second support assembly (18) includes a fixed block (1804) fixedly connected to the second screw jack (7), a guide rod (1801) fixedly provided on the fixed block (1804), the guide rod (1801) passing through the interior of the protrusion (1706), a second connecting plate (1802) fixedly provided on the protrusion (1706), a support frame (1803) fixedly connected to the second connecting plate (1802), the support frame (1803) slidably mounted on the movable plate (1805), and the movable plate (1805) is slidably connected to the outer frame (1601).

6. The hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load according to claim 5, characterized in that: The connecting assembly (19) comprises a fixing rod (1901) fixedly connected to a support frame (1803), a key sleeve (1902) fixedly provided on the fixing rod (1901), a spline rod (1903) connected to an inner key of the key sleeve (1902), and an extension rod (1904) fixedly connected to the spline rod (1903).

7. The hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load according to claim 6, characterized in that: The offset amplification component (20) comprises a first rack (2001) fixedly connected to the extension rod (1904); the side of the first rack (2001) is meshedly connected to the first gear (2002); the side of the first gear (2002) is meshedly connected to the second gear (2003); the rear side of the second gear (2003) is fixedly connected to the third gear (2005); the side of the third gear (2005) is meshedly connected to the second rack (2004); the number of teeth of the first gear (2002) is greater than the number of teeth of the second gear (2003); and the number of teeth of the first gear (2002) and the number of teeth of the third gear (2005) are the same.

8. The hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load according to claim 7, characterized in that: The guide assembly (21) includes a support base (2101) fixedly connected to the outer frame (1601), a first guide plate (2102) fixedly connected to the first rack (2001), and a second guide plate (2103) fixedly connected to the second rack (2004), the first guide plate (2102) and the second guide plate (2103) are all slidably connected to the support base (2101), and the first gear (2002), the second gear (2003) and the third gear (2005) are all rotationally connected to the support base (2101).

9. A hysteresis test method for reinforced concrete columns reinforced with corrugated steel pipes under secondary loads, using the hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary loads as claimed in claim 1, characterized in that: The following steps are involved: S1: Apply a pre-compression axial force N1 from the bottom of the first spring (14), and then reinforce. After the grouting material specimen (9) under the same curing conditions reaches the design strength, a vertical force is applied to the top of the specimen (9) using a vertical actuator (3) and a follower assembly (4). The pull rod (10) of the load-holding device is removed, and a horizontal reciprocating load is applied to the specimen (9) using a lateral actuator (8); S2: The vertical displacement of the end of the specimen (9) is measured by a longitudinal LVDT (13), and the lateral displacement of the specimen (9) at different height positions is measured by a lateral LVDT (12); the strain of concrete and grouting material is measured by an embedded strain gauge, and the strain at the crest, antinode and trough of the corrugated steel pipe is measured by a resistance strain rosette. The embedded strain gauge and the resistance strain rosette are arranged at the same position to obtain the distribution of the strain of each component along the cross-sectional height; S3: The measurement sections are 75mm, 225mm and 375mm away from both ends of the specimen (9) to measure the deformation of the column end and the range of the plastic hinge of the specimen (9); at each measurement section, a group of transverse strain gauges and longitudinal strain gauges are arranged at the center of the concrete, 8 longitudinal strain gauges are arranged along 45° of the grouting material, and 8 groups of strain rosettes are arranged along 45° of the corrugated steel pipe; based on the test results, the hysteresis curve and skeleton curve of the reinforced concrete pier column reinforced with the corrugated steel pipe body (11) are obtained, and the influence of the axial compression ratio, the thickness of the corrugated steel pipe and the thickness of the grouting material on the failure mode of the reinforced pier column and the mechanical indicators of the pier column bearing capacity, stiffness, ductility and viscous damping coefficient are studied; by comparing the test results of the reinforced concrete pier column reinforced with the corrugated steel pipe body (11) of different corrugation sizes and the reinforced concrete pier column reinforced with the flat steel pipe, the influence of the corrugation deformation energy dissipation on the energy dissipation capacity of the reinforced pier column is studied; the values ​​of the key parameters required for finite element modeling are determined.

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