Hysteresis test device and method for reinforced concrete column reinforced by corrugated steel pipe under secondary load

Abstract

The invention provides a hysteretic test device and method for a corrugated steel pipe reinforced reinforced concrete column under secondary loading, belongs to the technical field of hysteretic tests of reinforced concrete columns, and aims to solve the problem that an existing test device cannot reinforce a damaged reinforced concrete column under the working condition of considering the existing load. And then secondary load application is carried out, and the problems existing in an existing hysteresis test device are solved. According to the technical key points, an L-shaped rigid girder is arranged above the base, a test piece is arranged between the L-shaped rigid girder and the base, pull rods are installed on the periphery of the test piece, a corrugated steel pipe body is installed on the test piece, a follow-up assembly is arranged on the L-shaped rigid girder, a vertical actuator is installed above the follow-up assembly, and the vertical actuator is arranged on the base. A first screw type jack is installed on the L-shaped rigid girder, a second screw type jack is installed on the base, and a lateral actuator is arranged on the side face of the L-shaped rigid girder. The device is used for testing the reinforced pier column.

Description

Technical Field

[0001] The invention relates to the technical field of reinforced concrete column hysteresis test, in particular to a hysteresis test device and method for a corrugated steel pipe reinforced reinforced concrete column with 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 more and more attention. As an important part of the load-bearing structure of a building, the hysteresis performance of reinforced concrete columns under the action of seismic forces is one of the key factors in evaluating the seismic performance of buildings. The existing hysteresis test device for reinforced concrete columns still has some defects.

[0003] The invention patent with publication number CN118032552A discloses a low-cycle reciprocating load test device for FRP reinforced concrete columns in a complex environment, which 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 hysteresis 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 flat steel pipe reinforced concrete pier columns.

[0004] The existing test device generally cannot realize the test of secondary load: the first load is applied to the existing reinforced concrete column, the load is kept unchanged, the reinforced concrete column is reinforced, and the secondary load is applied after the reinforcement is completed. The existing technology also rarely mentions and discovers the importance of the secondary load problem. Therefore, it is urgent to propose a hysteresis test device and method for corrugated steel pipe reinforced concrete column with secondary load. 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 condition of existing load and then apply 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 corrugated steel pipe reinforced concrete column with secondary load.

[0006] 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 test piece is arranged 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 follow-up assembly is arranged 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 arranged on the side of the L-shaped rigid beam, lateral LVDTs are installed on the test piece and the corrugated steel pipe body, a longitudinal LVDT is installed on the test piece, through-type force sensors are installed around the bottom of the test piece, and a first spring is connected to the bottom of the through-type force sensor.

[0007] As a preferred scheme 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 arranged below the first pressure plate, a second pressure plate is arranged 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 screw jack, a detection assembly is installed between the second screw jack and the first screw 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 both 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 supporting assembly includes a fixed block fixedly connected to the second spiral jack, the fixed block is fixedly provided with a guide rod, the guide rod passes through the interior of the protrusion, the protrusion is fixedly provided with a second connecting plate, the second connecting plate is fixedly connected with a supporting frame, the supporting 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, the fixing rod is fixedly provided with a key sleeve, the key sleeve is keyed to a spline rod, and the spline rod is fixedly connected to an extension 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 meshedly connected to the first gear, the side of the first gear is meshedly connected to the second gear, the rear side of the second gear is fixedly connected to the third gear, the side of the third gear is meshedly connected to the 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 rotationally connected to the support seat.

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

[0016] S1: Apply 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, use the vertical actuator and follower assembly to apply vertical force to the top of the specimen, remove the tie rod of the load-holding device, and use the lateral actuator to apply horizontal reciprocating load to the specimen;

[0017] S2: The vertical displacement of the end of the specimen is measured by longitudinal LVDT, and the lateral displacement of the specimen at different heights is measured by lateral LVDT; the strain of concrete and grouting materials is measured by embedded strain gauges, and the strain at the crest / antinode / trough of the corrugated steel pipe is measured by resistive strain rosettes. The embedded strain gauges and resistive strain rosettes are arranged in the same position to obtain the distribution of strain of each component along the cross-sectional height;

[0018] S3: The measurement sections are 75mm, 225mm and 375mm away 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 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 the 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 arranged above the base, a test piece is arranged 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 arranged 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 arranged on the side of the L-shaped rigid beam. 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 is solved.

[0021] The test device provided by the present invention realizes the test of secondary load: the load is first applied to the existing reinforced concrete column, the load is kept unchanged, and the reinforced concrete column is reinforced, and the secondary load is applied after the reinforcement is completed. It can simulate the existing reinforced concrete pier column in the actual project, reinforce it under the working condition of upper load, and then test the mechanical properties after reinforcement.

[0022] The test device of the present invention can test the influence of parameters such as axial compression ratio, thickness of corrugated steel pipe and thickness of grouting material on the failure mode of reinforced pier column and mechanical indexes such as bearing capacity, stiffness, ductility and viscous damping coefficient of the pier column under the working condition of considering the existing load. The present invention is used to test the reinforced pier column.

[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 end of the specimen is measured by the longitudinal LVDT, and the lateral displacement of the specimen at different heights 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 the mechanical indicators such as the bearing capacity, stiffness, ductility, and viscous damping coefficient of the pier column; 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 key parameter values ​​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 test piece always in a state of applying vertical force, thereby ensuring the stability of the device during operation. An extension component is also provided on the device, 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, thereby ensuring the stability of the device during operation.

[0026] 3. By setting up the detection components, 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 moving 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 component and an offset amplification component. 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 combination with the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0029] Figure 1 It is a schematic diagram of the overall structure of the hysteresis test device for corrugated steel pipe reinforced reinforced concrete columns under secondary load of the present invention;

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

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

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

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

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

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

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

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

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

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

[0040] Fig.12 It is a schematic diagram of the split 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, bushing; 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 Components; 1701, bottom plate; 1702, connecting block; 1703, sliding rod; 1704, fixing tube; 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, guiding assembly; 2101, supporting 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, but the present invention may also be implemented in other ways different from those described herein, and 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] Secondly, the present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

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

[0046] like Figure 1-Figure 12 As shown, a 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 test piece 9 is arranged between the L-shaped rigid beam 2 and the base 1, tie rods 10 are installed around the test piece 9, a corrugated steel pipe body 11 is installed on the test piece 9, a follower assembly 4 is arranged 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, lateral LVDTs 12 are installed on the test piece 9 and the corrugated steel pipe body 11, a longitudinal LVDT 13 is installed on the test piece 9, through-type force sensors 15 are installed around the bottom of the test piece 9, and a first spring 14 is connected to the bottom of the through-type force sensor 15. 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 by 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 by using the lateral actuator 8.

[0047] The vertical displacement of the end of the specimen 9 is measured by the longitudinal LVDT 13, and the lateral displacement of the specimen 9 at different heights is measured by the lateral LVDT 12; the strain of concrete and grouting materials is measured by an embedded strain gauge, and the strain at the crest / antinode / 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;

[0048] The measuring 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 plastic hinge of specimen 9; in each measuring 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, thickness of corrugated steel pipe and thickness of grouting material on the failure mode of the reinforced pier column and mechanical indicators such as 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 columns is studied; 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 arranged below the first pressure plate 401, a second pressure plate 403 is arranged 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 downward, 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] In this embodiment, the extension component 5 includes an extension plate 501 slidably mounted on the side of the second pressure plate 403, and a shaft sleeve 502 is equidistantly mounted on the extension plate 501, and a second roller 503 is arranged in the shaft sleeve 502, and a stop block 504 is fitted on both the front and rear sides of the second roller 503, and the stop block 504 is fixedly connected to the extension plate 501, and the sides of the second pressure plate 403 and 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 components 5 at corresponding positions of the second pressure plate 403 according to the distance that the second pressure plate 403 needs to move. The second roller 503 on the extension component 5 can move in the shaft sleeve 502 without affecting the normal rotation of the second roller 503, thereby ensuring the stability of the device during operation, and the splicing function of multiple extension plates 501 can be realized 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 bottom 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 bottom plate 1701, a sliding rod 1703 is fixedly arranged 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 arranged 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 arranged on the second spring 1705. 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, the protrusion 1706 and the connecting ring 1707 will move downward, and the first spiral jack 6 can slide in the connecting block 1702 through the bottom plate 1701, so as to adapt to the change of 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, the movable plate 1805 and the outer frame 1601 are slidably connected, 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 the third gear 2005 rotates to 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, and 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 experimenter 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, 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, 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, as shown in FIG. Fig.11 As shown, the moving distance of the second rack 2004 can be subsequently calculated 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 reinforced concrete column with secondary load. First, Figure 1 As shown, a pre-compression axial force N1 is applied from the bottom of the first spring 14, and then reinforcement is performed. 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 by using the vertical actuator 3 and the 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 by using the lateral actuator 8. The vertical displacement of the end of the specimen 9 is measured by the longitudinal LVDT 13, and the lateral displacement of the specimen 9 at different heights is measured by the lateral LVDT 12; the strain of concrete and grouting material is measured by an embedded strain gauge, and the strain at the crest / antinode / trough of the corrugated steel pipe is measured by a resistance strain rosette. The embedded strain gauge and the resistance strain rosette are arranged in the same position to obtain the distribution of the strain of each component along the cross-sectional height.

[0058] The measuring 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 plastic hinge of specimen 9; in each measuring 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, thickness of corrugated steel pipe and thickness of grouting material on the failure mode of the reinforced pier column and mechanical indicators such as 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 columns is studied; the values ​​of key parameters required for finite element modeling are determined.

[0059] like Figure 1-Figure 4As shown, when the L-shaped rigid beam 2 moves laterally, the L-shaped rigid beam 2 can move on the first pressing plate 401 through the first roller 402 on the second pressing plate 403, so that the first pressing plate 401 of the device remains in a continuously pressed state. By installing the first connecting plate 505 into the docking groove 506, the splicing function of the second pressing plate 403 and the extension component 5 or multiple extension plates 501 is realized. The device can install different numbers of extension components 5 at the corresponding positions of the second pressing plate 403 according to the distance that the second pressing plate 403 needs to move. The second roller 503 on the extension component 5 can move in the shaft sleeve 502 without affecting the normal rotation of the second roller 503, thereby ensuring the stability of the device when working.

[0060] like Figure 5-Figure 12As shown, the first support assembly 16 is used to support the guide assembly 21, and the first hydraulic rod 1603 can be extended or shortened, and cooperates with the support block 1602 to provide stable support around the outer frame 1601. When the L-shaped rigid beam 2 is deformed, the vertical spacing between the first screw jack 6 and the second screw jack 7 changes, the slide bar 1703 slides in the fixed tube 1704, the second spring 1705 is compressed, the protrusion 1706 and the connecting ring 1707 move up and down under the guidance of the guide rod 1801, and the first screw jack 6 can slide in the connecting block 1702 through the bottom plate 1701, so as to adapt to the change of 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 groups of protrusions 1706 and the connecting ring 1707 can be compared laterally to detect whether the spacing between the first screw jack 6 and the second screw jack 7 changes, and then determine whether the L-shaped rigid beam 2 is deformed. The guide rod 1801 ensures that the protrusion 1706, the second connection 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 will not affect the deformation detection of the device when it moves sideways. 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, and 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, 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 movement distance of the second rack 2004 is greater than the first rack 2001, thereby magnifying 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. Fig.11 As shown, the moving distance of the second rack 2004 can be calculated later 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 the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. 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 corrugated steel pipe reinforced reinforced concrete columns under secondary load, comprising a base (1), characterized in that: An L-shaped rigid beam (2) is arranged above the base (1), a test piece (9) is arranged between the L-shaped rigid beam (2) and the base (1), tie rods (10) are installed around the test piece (9), a corrugated steel pipe body (11) is installed on the test piece (9), a follower assembly (4) is arranged 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 arranged 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 through-type force sensors (15) are 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).

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 follower assembly (4) comprises a first pressure plate (401) fixedly connected to the bottom of the vertical actuator (3), a first roller (402) is arranged below the first pressure plate (401), a second pressure plate (403) is arranged 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 connection assembly (19) is installed on the second support assembly (18), an offset amplification assembly (20) is connected to the connection assembly (19), and a guide assembly (21) is installed on the offset amplification assembly (20) and the first support assembly (16).

3. The hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load according to claim 2, 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 inside the shaft sleeve (502), a stopper (504) is fitted on both the front and rear sides of the second roller (503), the stopper (504) is fixedly connected to the extension plate (501), the side surfaces of the second pressure plate (403) and 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 inside the extension plate (501).

4. The hysteresis test device for reinforced concrete columns reinforced with corrugated steel pipes under secondary load according to claim 2, 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 installed at the bottom of the outer frame (1601), and a connecting plate (1604) is fixedly arranged on the outer frame (1601).

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 detection assembly (17) comprises a bottom plate (1701) fixedly connected to the bottom of the first screw jack (6); a connecting block (1702) is slidably mounted at the bottom of the bottom plate (1701); a sliding rod (1703) is fixedly mounted below the connecting block (1702); a fixing tube (1704) is fitted on the outer side of the sliding rod (1703); a second spring (1705) is mounted at the bottom of the sliding rod (1703); a protrusion (1706) is fixedly mounted on the second spring (1705); a connecting ring (1707) is welded to the protrusion (1706); the protrusion (1706) and the connecting ring (1707) are both slidably connected to the fixing tube (1704); and the fixing tube (1704) and the second screw jack (7) are fixedly connected.

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 second support assembly (18) comprises a fixed block (1804) fixedly connected to the second screw jack (7), a guide rod (1801) fixedly arranged on the fixed block (1804), the guide rod (1801) passing through the interior of the protrusion (1706), a second connecting plate (1802) fixedly arranged 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).

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 connection assembly (19) comprises a fixing rod (1901) fixedly connected to a support frame (1803), a key sleeve (1902) being fixedly provided on the fixing rod (1901), a spline rod (1903) being key-connected inside the key sleeve (1902), and an extension rod (1904) being fixedly connected to the spline rod (1903).

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 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); the number of teeth of the first gear (2002) is the same as the number of teeth of the third gear (2005).

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

10. A hysteresis test method for reinforced concrete columns reinforced with corrugated steel tubes under secondary loads, using the hysteresis test device for reinforced concrete columns reinforced with corrugated steel tubes under secondary loads as claimed in claim 1, characterized in that: The following steps are involved: S1: a pre-compression axial force N1 is applied from the bottom of the first spring (14), and then reinforcement is performed. 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 heights 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 / 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 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 the 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) 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; and the values ​​of key parameters required for finite element modeling are determined.

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