A multi-working-condition testing device and testing method suitable for complex stress of structure member compression-bending-torsion-shear

Abstract

The application provides a kind of multi-working condition test device and test method suitable for structure member compression-bending-torsion-shear complex stress, and belongs to the field of structural engineering.To solve the problems of existing test device, such as difficult installation or collaborative loading, significant additional load at the connection between loading system and member, non-coincidence of device torsion center and specimen geometric center, large weight of specimen torsion arm, and difficult guarantee of specimen bottom boundary condition.The test loading device realizes load transmission through lateral reaction frame, axial reaction frame and ground beam;realizes boundary conditions of specimen under different load working conditions through translational hinge, one-way hinge, cross hinge, spherical hinge and torsion hoop;realizes single load, double load coupling, three load coupling and four load coupling working conditions of structure member through adjusting specimen height and position of lateral force action point.It provides strong technical support for accurate and efficient implementation of basic test research on real mechanical response of structure member under different load working conditions.

Description

Technical Field

[0001] This invention relates to the field of structural engineering technology, and more specifically, to a multi-condition test device and test method suitable for structural members subjected to complex forces of compression, bending, torsion, and shear. Background Technology

[0002] In practical engineering, structural members are often subjected to coupled stresses of compression, bending, torsion, and shear under loads such as self-weight, wind, and earthquakes, resulting in complex failure modes. Existing research often only considers the mechanical properties of structural members under single-stress (axial compression or pure bending) or compression-bending coupled stress states. While this serves as fundamental research, it fails to reflect the true failure modes and working mechanisms of structural members and cannot accurately account for the significant load coupling effects in design methods. Existing experimental devices considering complex stresses on structural members often employ loading methods combining dual actuators or a single actuator with a two-force member. Although these methods can simulate complex stress states, they suffer from difficulties in installation or coordinated loading, significant additional loads at the connection between the loading system and the member, misalignment between the device's torsional center and the specimen's geometric center, large self-weight of the specimen's torsional arm, and difficulty in ensuring the bottom boundary conditions of the specimen. These issues severely affect the operability, flexibility, and accuracy of measured data in complex stress tests, limiting the revelation of the working mechanisms of structural members under true stress states and the establishment of corresponding design methods. Summary of the Invention

[0003] The technical problem to be solved by this invention is:

[0004] To address the problems of existing test devices, such as difficulties in installation or coordinated loading, significant additional loads at the connection between the loading system and the components, non-coincidence between the torsional center of the device and the geometric center of the specimen, large self-weight of the specimen's torsion arm, and difficulty in ensuring the bottom boundary conditions of the specimen.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0006] This invention provides a multi-condition testing device suitable for structural components subjected to complex compression-bending-torsion-shear forces, including a ground beam and lateral reaction frames and axial reaction frames on the ground beam;

[0007] The lateral reaction frame includes two right-angled triangular frames. The straight edges of the base of the two right-angled triangular frames are connected to the ground beam. The straight edges of the sides of the two triangular frames are connected by a detachable lateral loading beam. The lateral loading beam can move up and down along the straight edges of the sides of the right-angled triangular frames. A detachable lateral loading system is connected to the lateral loading beam. The lateral loading system includes a lateral force loading device and a lateral connecting hinge. The two ends of the lateral force loading device are respectively provided with lateral connecting hinges. One side of the lateral force loading device is connected to the lateral loading beam through the connecting hinge and can move up and down with the lateral loading beam. The other side of the lateral force loading device is connected to a detachable torsion steel arm through the connecting hinge.

[0008] The axial reaction frame is a portal frame structure. An axial loading system is provided at the lower end of the crossbeam of the axial reaction frame. The axial loading system, from top to bottom, includes a translational hinge, an axial force sensor, an axial jack, and an axial connecting hinge. The upper end of the translational hinge is connected to the crossbeam of the axial reaction frame. Force sensor clamps are provided at both the upper and lower ends of the axial force sensor, and the two force sensor clamps are fixed by at least four connecting plates. The lower end of the translational hinge is connected to the upper force sensor clamp, and the lower force sensor clamp is connected to the upper end of the axial jack. The lower end of the axial jack is connected to a loading pad. An axial connecting hinge is provided below the loading pad, and a connecting hinge base plate clamp is provided below the axial connecting hinge to ensure that the axial load is evenly applied to the top of the specimen while preventing lateral sliding of the axial connecting hinge.

[0009] It also includes a detachable torsion steel arm, which is used to connect with the reserved crossbeam of the specimen. The detachable torsion steel arm is a variable cross-section steel beam. The detachable torsion steel arm is connected by a pre-embedded steel component and a screw rod pre-embedded in the reserved crossbeam of the specimen.

[0010] It also includes a torsion clamp, which is used to connect the specimen to the axial reaction frame. The torsion clamp includes an inner ring plate, an outer ring plate, torsion rollers and a clamp connecting plate. Several torsion rollers are provided between the inner ring plate and the outer ring plate. Several roller limiting plates are provided at both ends of the torsion rollers. Each roller limiting plate is used to limit two torsion rollers. A clamp connecting plate is provided outside the outer ring plate and is connected to the axial reaction frame.

[0011] It also includes a bottom pier limiting device, which includes two bottom pier limiting steel beams and hand jacks. The two bottom pier limiting steel beams are connected to the ground beam, and at least four hand jacks are symmetrically provided on both sides of the two bottom pier limiting steel beams.

[0012] Furthermore, the lateral connecting hinge can be a lateral one-way hinge or a lateral cross hinge. When the specimen has only a one-way rotation angle, the lateral connecting hinge is a lateral one-way hinge; when the specimen has a two-way rotation angle, the lateral connecting hinge is a lateral cross hinge.

[0013] Furthermore, the lateral force loading device can be an MTS, or the lateral force loading device can be a tension / compression jack. When the lateral force loading device is a tension / compression jack, one end of the tension / compression jack is connected to a lateral connecting hinge on one side, and the other end of the tension / compression jack is connected to a lateral force sensor and then connected to a lateral connecting hinge on the other side. It also includes a displacement sensor installed on the tension / compression jack.

[0014] Furthermore, when the specimen has a unidirectional rotation angle, the axial connecting hinge is a unidirectional hinge; when the specimen has torsional deformation, the axial connecting hinge is a ball joint.

[0015] Furthermore, when the specimen exhibits a second-order effect under lateral load, the translational hinge is fixed to the crossbeam of the axial reaction frame.

[0016] Furthermore, the translational hinge includes a top plate buckle, a top plate, rollers, a loading plate, and upper and lower plate buckles. The top plate is provided with at least four top plate buckles, which are used to fix the axial loading system to the crossbeam of the axial reaction frame. Below the top plate are two loading plates and several rollers between the two loading plates. The two loading plates are connected by at least four upper and lower plate buckles.

[0017] Furthermore, the inner ring plate of the torsion clamp is locally roughened or a rubber pad is installed inside the inner ring plate; two adjacent roller limiting plates are stacked alternately, and each roller limiting plate is limited at the end by a nut to ensure that the bearings of each roller do not tilt or separate during the torsion process.

[0018] Furthermore, the maximum lateral force and axial force that the lateral reaction frame and axial reaction frame can withstand are both higher than the range of the lateral MTS or tension / compression jack.

[0019] Furthermore, the crossbeam of the lateral reaction frame has pre-drilled bolt holes for bolting to the lateral connecting hinge of the lateral loading system; the crossbeam of the specimen has pre-drilled embedded screw holes and pre-drilled bolt holes for screw or bolting to the detachable torsion steel arm and the embedded steel component, respectively; the detachable torsion steel arm has lateral connecting screw holes for bolting to the lateral connecting hinge of the lateral loading system; the screw is a high-strength screw, and the bolt is a high-strength bolt.

[0020] A test method utilizing a multi-condition test apparatus suitable for complex compression-bending-torsion-shear stresses on structural members includes the following steps:

[0021] Step 1: Installation process. Design and install the ground beam according to the ground anchor size of the test site. Then install the lateral reaction frame and axial reaction frame on the ground beam. Restrict the specimen bottom block to the ground beam through the bottom block limiting device. Restrict the planar lateral displacement and rotation of the specimen through the hand jack on the bottom block limiting device. Then install the detachable torsion steel arm. Selectively install the torsion clamp, lateral loading system and axial loading system according to the type of force measured.

[0022] Step 2, Testing Process: When only the axial loading system is installed, axial compression and eccentric compression loading can be achieved; when only the lateral loading system is installed, shear and bending loading can be achieved by adjusting the height of the specimen, i.e., the shear span ratio; by rotating the axial reaction frame of the specimen 180° and setting the point of application of the lateral loading system at the geometric center of the specimen, compression-bending, bending-shear, compression-shear, and compression-bending-shear coupled loading can be achieved; by installing the torsion clamp of the specimen, pure torsion and compression-torsion coupled loading can be achieved; by adjusting the position of the lateral loading system on the detachable torsion steel arm, i.e., the distance from the point of application of the lateral load to the geometric center of the specimen, bending-torsion, shear-torsion, compression-bending-torsion, compression-shear-torsion, and compression-bending-torsion-shear coupled loading can be achieved.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] This invention discloses a multi-condition testing device and method suitable for structural members under complex compression-bending-torsion-shear loads. Load transfer is achieved through lateral reaction frames, axial reaction frames, and ground beams; boundary conditions of specimens under different load conditions are achieved through translational hinges, unidirectional hinges, cross hinges, ball hinges, and torsional clamps; and a testing loading system is implemented for single-load conditions of compression, bending, shear, and torsion, dual-load coupled conditions of compression-bending, compression-torsion, compression-shear, bending-torsion, bending-shear, and shear-torsion, three-load coupled conditions of compression-bending-torsion, compression-bending-shear, compression-shear-torsion, and four-load coupled conditions of compression-bending-torsion-shear. This provides strong technical support for the accurate and efficient fundamental experimental research on the real mechanical response of structural specimens (columns, beams, and walls) under different load conditions, namely monotonic and reciprocating loading. In summary, this complex load-loading device has the following advantages:

[0025] (1) It has multi-condition loading capability and can flexibly adjust the position of the axial loading system and the lateral loading system of the loading device, the height of the specimen and the boundary conditions of the corresponding load conditions, namely unidirectional rotation, bidirectional rotation, translation and free rotation in the plane, to realize the single action and arbitrary combination action conditions of the structural members under the four basic loads of compression, bending, shear and torsion.

[0026] (2) It effectively solves the problem that the torsion center of the existing device under pure torsion or compression-torsion loading does not coincide with the geometric center of the specimen. By using the torsion clamp, the bending deformation and shear deformation of the specimen under lateral load can be effectively restricted. At the same time, the specimen can rotate freely around its torsion center, which significantly reduces the test error caused by the non-coincidence of the torsion center of the specimen and the loading device when implementing pure torsion or compression-torsion loading through two-force members.

[0027] (3) It effectively reduces the additional load generated at the connection between the axial and lateral loading system and the specimen. By using translational hinges, ball hinges, one-way hinges and cross hinges in combination, it can be realized that when the MTS or tension-compression jack applies a lateral load to the specimen, there is only a load along the length of the actuator or jack, without any other additional bending moment or torque. In the axial direction, the specimen also only has a vertically downward axial force and a second-order bending moment generated by the lateral deformation of the specimen, without any other additional bending moment and torque generated by the boundary constraints. The above measures ensure the test accuracy when the structural components are subjected to complex forces, and also ensure the safety of the axial and lateral loading system of the device itself.

[0028] (4) The self-weight of the structural components is reduced. By connecting the reliable detachable torsion steel arm, the structural self-weight of the specimen is reduced, and the structural components are prevented from generating excessive additional bending moment due to the torsion arm, which would cause significant test errors. At the same time, the detachable torsion steel arm also reduces the construction cost in the process of manufacturing the structural components.

[0029] (5) Improved operability and installability of loading. This invention only requires one set of lateral loading device, that is, using MTS or tension-compression jacks, to realize multi-condition loading of complex forces of compression-bending-torsion-shear on the specimen, avoiding the coordination problem of dual MTS system and reducing the connection device between loading device and specimen; at the same time, the axial reaction frame and lateral reaction frame of this invention are connected to the ground beam, avoiding too many anchoring and reducing the installation difficulty of reaction device; the whole reaction frame has good integrity, strong installability and operability. Attached Figure Description

[0030] Figure 1 This invention provides a three-dimensional multi-condition testing device suitable for structural members subjected to complex compression-bending-torsion-shear stresses, as described in this embodiment. Figure 1 ;

[0031] Figure 2 This is a perspective view of the test apparatus under pure torsion or compression-torsion loading in an embodiment of the present invention;

[0032] Figure 3 This is a perspective view of the connection between the reserved crossbeam and the detachable torsion steel arm in an embodiment of the present invention;

[0033] Figure 4This is a perspective view of the axial loading system in an embodiment of the present invention;

[0034] Figure 5 This is a perspective view of two types of connecting hinges in the lateral loading system of this invention.

[0035] Figure 6 This is a perspective view of the torsion clamp in an embodiment of the present invention;

[0036] Figure 7 This is a perspective view of the bottom pier limiting device in an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Lateral reaction frame; 2. Lateral loading beam; 3. Lateral loading system; 4. Detachable torsion steel arm; 5. Axial reaction frame; 6. Axial loading system; 7. Specimen; 8. Specimen base; 9. Base limiting device; 11. Torsional clamp; 12. Ground beam;

[0039] 3-1, MTS; 3-2, Lateral one-way hinge; 3-3, Tension / compression jack; 3-4, Lateral force sensor; 3-5, Lateral cross hinge;

[0040] 4-1. Specimen pre-reserved crossbeam; 4-2. Pre-embedded steel components; 4-3. Pre-embedded bolt holes; 4-4. Pre-set bolt holes; 4-5. Lateral connection bolt holes;

[0041] 6-1. Top plate buckle; 6-2. Top plate; 6-3. Roller; 6-4. Loading plate; 6-5. Upper and lower plate buckles; 6-6. Force sensor clamp; 6-7. Axial force sensor; 6-8. Connecting plate; 6-9. Axial jack; 6-10. Loading pad; 6-11. Ball joint; 6-12. Ball joint base plate clamp;

[0042] 9-1. Hand-held jack; 9-2. Bottom pier limiting steel beam; 9-3. L-shaped connecting plate;

[0043] 11-1 Inner ring plate; 11-2 Outer ring plate; 11-3 Outer ring plate connecting bolts; 11-4 Torsion roller; 11-5 Roller limiting plate; 11-6 Clamp connecting plate. Detailed Implementation

[0044] In the description of this invention, it should be noted that the terms used in the various embodiments, such as "upper," "lower," "front," "rear," "left," and "right," which indicate orientation, are only used to simplify the description of the positional relationships based on the accompanying drawings and do not mean that the components and devices referred to must be operated in accordance with the specific orientations and defined operations, methods, and structures in the specification. Such directional terms do not constitute a limitation of this invention.

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0046] Specific Implementation Plan 1: Combining Figures 1 to 7 As shown, the present invention provides a multi-condition test device suitable for structural components subjected to complex forces of compression, bending, torsion and shear, including a ground beam 12 and a lateral reaction frame 1 and an axial reaction frame 5 on the ground beam 12;

[0047] The lateral reaction frame 1 includes two right-angled triangular frames. The straight edges of the bottom surfaces of the two right-angled triangular frames are connected to the ground beam 12. The straight edges of the sides of the two triangular frames are connected by a detachable lateral loading beam 2. The lateral loading beam 2 can move up and down along the straight edges of the sides of the right-angled triangular frames. A lateral loading system 3 is detachably connected to the lateral loading beam 2. The lateral loading system 3 includes a lateral force loading device and a lateral monitoring device. Lateral connecting hinges are provided at both ends of the lateral force loading device. One side of the lateral force loading device is installed on the lateral loading beam 2 through the lateral connecting hinge and can move up and down with the lateral loading beam 2. This facilitates the up, down, left, and right movement of the lateral force loading device. The other side of the lateral force loading device is connected to a detachable torsion steel arm 4 through a connecting hinge.

[0048] The lateral connecting hinge can be a lateral one-way hinge 3-2 or a lateral cross hinge 3-5. When the specimen 7 has only a one-way rotation angle, the lateral connecting hinge is a lateral one-way hinge 3-2; when the specimen 7 has a two-way rotation angle, the lateral connecting hinge is a lateral cross hinge 3-5.

[0049] The lateral force loading device can be an MTS 3-1, or the lateral force loading device can be a tension / compression jack 3-3; when the lateral force loading device is a tension / compression jack 3-3, one end of the tension / compression jack 3-3 is connected to a lateral connecting hinge, and the other end of the tension / compression jack 3-3 is connected to a lateral force sensor 3-4 and a lateral connecting hinge in sequence, and a displacement sensor is provided on the tension / compression jack 3-3;

[0050] The axial reaction frame 5 is a portal frame structure. The lower end of the top beam of the axial reaction frame 5 is provided with an axial loading system 6. The axial loading system 6 includes, from top to bottom, a translational hinge, an axial force sensor 6-7, an axial jack 6-9, and an axial connecting hinge. The upper end of the translational hinge is connected to the beam of the axial reaction frame 5. Both the upper and lower ends of the axial force sensor 6-7 are provided with force sensor clamps 6-6. The two force sensor clamps 6-6 are fixed by at least two connecting plates 6-8. The lower end of the translational hinge is connected to the upper force sensor clamp 6-6. The lower force sensor clamp 6-6 is connected to the upper end of the axial jack 6-9. The lower end of the axial jack 6-9 is connected to the loading pad 6-10. An axial connecting hinge is provided below the loading pad 6-10. A connecting hinge base plate clamp is provided below the axial connecting hinge to ensure that the axial load can be evenly applied to the top of the specimen 7, while preventing the axial connecting hinge from sliding laterally.

[0051] The translational hinge includes a top plate buckle 6-1, a top plate 6-2, rollers 6-3, a loading plate 6-4, and upper and lower plate buckles 6-5. The top plate 6-2 is provided with at least four top plate buckles 6-1 for fixing the axial loading system 6 to the crossbeam of the axial reaction frame 5. Below the top plate 6-2 are two loading plates 6-4 and several rollers 6-3 between the two loading plates 6-4. The two loading plates 6-4 are connected by at least four upper and lower plate buckles 6-5.

[0052] The force sensor clamp 6-6 below is welded with a tenon to prevent the axial jack 6-9 from falling off due to insufficient lateral friction.

[0053] It also includes a safety rope for securing and protecting the entire axial loading system 6, so that it will not fall even if the specimen suffers severe damage.

[0054] When specimen 7 has a unidirectional rotation angle, the axial connecting hinge is an axial unidirectional hinge; when the specimen has torsional deformation, the axial connecting hinge is a ball joint 6-11, and the connecting hinge base plate clamping plate is a ball joint base plate clamping plate 6-12.

[0055] The translational hinge is used to realize the axial load of the specimen 7. It is installed when the specimen 7 has a second-order effect under the action of lateral load. The translational hinge is fixed on the crossbeam of the axial reaction frame 5.

[0056] It also includes a detachable torsion steel arm 4, which is used to connect with the reserved crossbeam 4-1 of the specimen. The detachable torsion steel arm 4 is a variable cross-section steel beam. The detachable torsion steel arm 4 is connected by a pre-embedded steel component 4-2 and a screw rod that are pre-embedded on the reserved crossbeam 4-1 of the specimen.

[0057] It also includes a torsion clamp 11, which is used to fix the specimen 7 on the axial reaction frame 5, and to limit the bending deformation and shear deformation of the specimen 7 under pure torsional or compressive-torsional loading. The torsion clamp 11 only limits the lateral deformation of the specimen 7 caused by bending moment and shear force, and does not limit the torsional deformation. The torsion clamp 11 includes an inner ring plate 11-1, an outer ring plate 11-2, a torsion roller 11-4, and a clamp connecting plate 11-6. A torsion roller 11-4 is provided between the two rollers 11-2. Each end of the torsion roller 11-4 is provided with several roller limiting plates 11-5. Each roller limiting plate 11-5 is used to limit the two adjacent torsion rollers 11-4. The two adjacent roller limiting plates 11-5 are stacked alternately to ensure that the bearings of each roller do not tilt or separate during the torsion process, thereby improving the rolling efficiency of the rollers. The outer ring plate 11-2 is connected to the axial reaction frame 5 through a clamp connecting plate 11-6.

[0058] The outer ring plate 11-2 includes one or at least two outer ring plate units. When the outer ring plate 11-2 includes at least two outer ring plate units, adjacent two outer ring plate units are connected by outer ring plate connecting bolts 11-3.

[0059] The height of the torsion clamp 11 is greater than or equal to 100mm, and the thickness of the inner ring plate 11-1 and the outer ring plate 11-2 is greater than or equal to 10mm, and should be designed according to the size of the specimen 7; in order to increase the friction between the inner ring plate 11-1 of the torsion clamp 11 and the surface of the specimen 7, the interior of the inner ring plate 11-1 of the torsion clamp 11 can be locally roughened or a rubber pad can be installed inside.

[0060] The torsion clamp 11 can be circular as in this invention, or it can be other cross-sectional shapes, including square, rectangular, elliptical, and other shapes suitable for other specimens 7;

[0061] It also includes a bottom pier limiting device 9, which includes two bottom pier limiting steel beams 9-2 and a hand jack 9-1. The two bottom pier limiting steel beams 9-2 are connected to the ground beam 12. At least two hand jacks 9-1 are symmetrically provided on both sides of the two bottom pier limiting steel beams 9-2 to limit the lateral displacement and rotation of the specimen 7 and ensure the boundary conditions for the bottom of the specimen 7 to be embedded.

[0062] The bottom pier limiting steel beam 9-2 is connected to the ground beam 12 via an L-shaped connecting plate 9-3.

[0063] The structural component in the name has the same meaning as specimen 7.

[0064] Preferably, the steel strength of the rollers of the translational hinge, lateral one-way hinge, axial one-way hinge, and lateral cross hinge is not lower than Q355, and they have all undergone quenching, smoothing, and oiling treatments to reduce their friction during use.

[0065] Preferably, the lateral reaction frame 1 and the axial reaction frame 5 are able to withstand a maximum lateral force and axial force that are higher than the range of the MTS3-1 or the tension / compression jack 3-3, and the steel plate thickness is higher than or equal to 20mm; so as to ensure that the lateral reaction frame 1 and the axial reaction frame 5 will not be damaged due to exceeding the range.

[0066] Preferably, the ball joint 6-11, lateral one-way joint, axial one-way joint, lateral cross joint, and translational joint must ensure their rotational capacity during the loading process, and the frictional force of the roller should be verified before the test.

[0067] Preferably, the embedded steel component 4-2 embedded in the specimen 7 is connected to the reinforcing steel in the reserved crossbeam 4-1 of the specimen, and the connection must ensure shear resistance, bending resistance and local compressive bearing capacity.

[0068] Preferably, the crossbeam of the lateral reaction frame 1 has pre-drilled bolt holes for bolt connection with the lateral connecting hinge of the lateral loading system 3; the crossbeam 4-1 of the specimen 7 has pre-drilled embedded screw holes 4-3 and pre-drilled bolt holes 4-4 for screw or bolt connection with the detachable torsion steel arm 4 and the embedded steel component 4-2, respectively; the detachable torsion steel arm 4 has lateral connecting screw holes 4-5 for bolt connection with the lateral connecting hinge of the lateral loading system 3; the screw is a high-strength screw, or the bolt is a high-strength bolt.

[0069] Preferably, the cross-section of the ground beam 12 is provided with stiffening ribs, and the thickness of the stiffening ribs is greater than or equal to 20mm.

[0070] Preferably, the thickness of the steel profiles and steel plates used in the lateral reaction frame 1, axial reaction frame 5, ground beam 12 and bottom pier limiting device 9 is greater than or equal to 25mm.

[0071] Preferably, the bottom of the specimen 7 should be able to withstand the maximum lateral and axial forces generated during the loading process of the specimen, and should also be able to withstand the local pressure of the screw and the hand jack 9-1.

[0072] The specimen 7 includes a columnar main body, a pre-reserved crossbeam 4-1 at the upper end, and a base at the lower end.

[0073] Specific Implementation Plan Two: Combining Figures 1 to 7 As shown, this invention provides a multi-condition test method suitable for structural members subjected to complex compression-bending-torsion-shear forces, comprising the following steps:

[0074] Step 1: Installation process. Design and install ground beam 12 according to the ground anchor size of the test site. Then install lateral reaction frame 1 and axial reaction frame 5 on ground beam 12. Restrict specimen bottom 8 to ground beam 12 by bottom pier limiting device 9. Restrict the planar lateral displacement and rotation of specimen 7 by hand jack 9-1 on bottom pier limiting device 9. Then install detachable torsion steel arm 4. Selectively install torsion clamp 11, lateral loading system 3 and axial loading system 6 according to the measured force type.

[0075] Step 2, Testing Process: When only the axial loading system 6 is installed, axial compression and eccentric compression loading can be achieved; when only the lateral loading system 3 is installed, shear and bending loading of the specimen 7 can be achieved by adjusting the height of the specimen 7, i.e., the shear span ratio; by rotating the axial reaction frame 5 of the specimen 7 by 180° and setting the point of application of the lateral loading system 3 at the geometric center of the specimen 7, compression-bending, bending-shear, compression-shear, and compression-bending-shear coupled loading of the specimen 7 can be achieved; by installing the torsion clamp 11 of the specimen 7, pure torsion and compression-torsion coupled loading can be achieved; by adjusting the position of the lateral loading system 3 on the detachable torsion steel arm 4, i.e., the distance from the point of application of the lateral load to the geometric center of the specimen 7, bending-torsion, shear-torsion, compression-bending-torsion, compression-shear-torsion, and compression-bending-torsion-shear coupled force loading of the specimen 7 can be achieved.

[0076] The other combinations and connections in this implementation scheme are the same as in Specific Implementation Scheme 1.

[0077] Preferably, a one-way hinge should be used when specimen 7 exhibits only unidirectional rotation; a cross hinge should be used when specimen 7 exhibits bidirectional rotation; and a ball hinge should be used when specimen 7 exhibits torsional deformation. This is because the deformation of specimen 7 differs significantly under different load coupling conditions.

[0078] Effect verification

[0079] For traditional reinforced concrete members, multi-condition tests under complex compression-bending-torsion-shear stresses are conducted using the complex stress testing device and method described in this invention. The specific test process is as follows:

[0080] Step 1: Installation process. Design and install ground beam 12 according to the ground anchor size of the test site. Then install lateral reaction frame 1 and axial reaction frame 5 on ground beam 12. Restrict the prepared specimen bottom pier 8 on ground beam 12 by bottom pier limiting device 9. Restrict the planar lateral displacement and rotation of specimen 7 by hand jack 9-1 on bottom pier limiting device 9. Then install detachable torsion steel arm 4 on specimen reserved crossbeam 4-1. Selectively install torsion clamp 11, lateral loading system 3 and axial loading system 6 according to the required stress conditions. Appropriately select one-way hinge, cross hinge, ball hinge and translational hinge.

[0081] Step 2, Testing Process: When only the axial loading system 6 is installed, axial compression and eccentric compression loading can be achieved; when only the lateral loading system 3 is installed, shear and bending loading of the specimen 7 can be achieved by adjusting the height of the reinforced concrete specimen, i.e., the shear span ratio; by rotating the axial reaction frame 5 180° and setting the point of application of the lateral loading system 3 at the geometric center of the reinforced concrete specimen, compression-bending, bending-shear, compression-shear, and compression-bending-shear coupled loading can be achieved; when only axial force exists, the use of a one-way hinge or ball joint 6-11 in the axial loading system 6 has no impact on the test results. Obviously, when axial force and bending moment or shear force act together, the axial loading system 6 should use a one-way hinge and a translational hinge should be installed to consider the second-order effect of axial force; installing a torsion clamp 11 on the reinforced concrete specimen can realize pure torsion and compression-torsion coupled loading; by adjusting the position of the lateral loading system 3 on the detachable torsion steel arm 4, that is, the distance from the lateral load application point to the geometric center of the reinforced concrete specimen, and simultaneously changing the height of the specimen 7, bending-torsion, shear-torsion, compression-bending-torsion, compression-shear-torsion, and compression-bending-torsion-shear coupled loading can be realized.

[0082] Step 3: Verification process. The deformation characteristics of the reinforced concrete specimen under different working conditions are monitored by using displacement gauges, rotation gauges, and linear displacement gauges installed on the torsion arm of the reinforced concrete specimen.

[0083] When the specimen is under axial compression, eccentric compression, bending and shear conditions, significant axial deformation, bending deformation and shear deformation can be observed in specimen 7. Its failure and deformation are consistent with the classical elastoplastic theory. The lateral deflection curve generated by bending is close to a half-sine wave, and the shear displacement generated by shear force is close to that of conventional simply supported beam test. Under simple load conditions, the overall deformation law and failure mode of the specimen are in good agreement with the test results using a conventional hydraulic press.

[0084] When the specimen is in pure torsion and compression-torsion states, it can be observed that specimen 7 only undergoes torsional deformation, and a torsional diagonal crack with a 45° direction is generated on the surface of specimen 7. When axial force is present, the angle between the torsional diagonal crack and the column length direction is less than 45°. The lateral displacement of the column top does not exceed 0.2 mm, the lateral slip of the specimen base 8 is less than 0.1 mm, and the in-plane and out-of-plane rotation angles do not exceed 0.01°, indicating that the base limiting device 9 of the test device can effectively ensure the embedding conditions of specimen 7. The error between the directly measured torsion angle and the torsion angle calculated by the lateral displacement of the loading point of the torsion arm of specimen 7 does not exceed 0.05°, indicating that the detachable torsion steel arm 4 is reliably connected, and the torsion clamp 11 of the device achieves the limitation of bending and shear deformation of specimen 7, while not affecting its torsional deformation. That is, using the above test device, specimen 7 can freely torsion around the geometric center.

[0085] When specimen 7 was subjected to bending-torsion, compression-bending-torsion, and compression-bending-torsion-shear coupling effects, significant bending and torsional deformations were observed. The translational hinge in the axial loading system 6 exhibited significant horizontal displacement. The lateral slippage of the specimen's base 8 was also less than 0.1 mm. The in-plane and out-of-plane rotation angles did not exceed 0.05°, and the out-of-plane displacement of the top of specimen 7 was within 1.2 mm. These measurement results further demonstrate that the base pier limiting device 9 of the test apparatus effectively ensures the embedding condition of specimen 7, and the top axial loading system 6 also effectively limits the out-of-plane displacement of specimen 7 while ensuring that the axial force can translate along with the horizontal lateral displacement, effectively testing... The second-order effect caused by axial force is considered; the lateral deformation of the specimen at the loading point of the torsional steel arm can be decomposed into shear deformation, torsional deformation and bending deformation of the specimen. The results after decomposition are in good agreement with the directly measured column top displacement and column top steel arm torsion angle. The deformation characteristics and failure mode of the specimen under this device are consistent with the actual situation, which further shows that the loading device is reliable and can realize the multi-condition test loading of the specimen under complex stress of compression-bending-torsion-shear. It also further verifies the innovation and operability of the loading device, and can provide strong technical support for the basic experimental research on the accurate and efficient realization of the real mechanical response of structural components under different load conditions.

[0086] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A multi-condition testing device suitable for structural members subjected to complex compression-bending-torsion-shear stresses, characterized in that: Includes ground beam (12) and lateral reaction frame (1) and axial reaction frame (5) on ground beam (12); The lateral reaction frame (1) includes two right-angled triangular frames. The straight edges of the bottom surfaces of the two right-angled triangular frames are connected to the ground beam (12). The straight edges of the sides of the two triangular frames are connected by a detachable lateral loading beam (2). The lateral loading beam (2) can move up and down along the straight edges of the sides of the right-angled triangular frames. A detachable lateral loading system (3) is connected to the lateral loading beam (2). The lateral loading system (3) includes a lateral force loading device and a lateral monitoring device. The two ends of the lateral force loading device are respectively provided with lateral connecting hinges. One side of the lateral force loading device is connected to the lateral loading beam (2) through the connecting hinge and can move up and down with the lateral loading beam (2). The other side of the lateral force loading device is connected to a detachable torsion steel arm (4) through the connecting hinge. The axial reaction frame (5) is a portal frame structure. The lower end of the crossbeam of the axial reaction frame (5) is provided with an axial loading system (6). The axial loading system (6) includes, from top to bottom, a translational hinge, an axial force sensor (6-7), an axial jack (6-9), and an axial connecting hinge. The upper end of the translational hinge is connected to the crossbeam of the axial reaction frame (5). Both the upper and lower ends of the axial force sensor (6-7) are provided with force sensor clamps (6-6). The two force sensor clamps (6-6) are connected by at least four connecting plates. (6-8) Fixed, the lower end of the translational hinge is connected to the upper force sensor clamp (6-6), the lower force sensor clamp (6-6) is connected to the upper end of the axial jack (6-9), the lower end of the axial jack (6-9) is connected to the loading pad (6-10), the loading pad (6-10) is provided with an axial connecting hinge below, and the axial connecting hinge is provided with a connecting hinge base plate clamp below, which is used to ensure that the axial load can be evenly applied to the top of the specimen (7) and at the same time prevent the axial connecting hinge from sliding laterally; It also includes a detachable torsion steel arm (4), which is used to connect with the specimen reserved crossbeam (4-1) of the specimen (7). The detachable torsion steel arm (4) is a variable cross section steel beam. The detachable torsion steel arm (4) is connected by a pre-embedded steel component (4-2) and a screw rod pre-embedded on the specimen reserved crossbeam (4-1). It also includes a torsion clamp (11), which is used to connect the specimen (7) to the axial reaction frame (5). The torsion clamp (11) includes an inner ring plate (11-1), an outer ring plate (11-2), torsion rollers (11-4), and a clamp connecting plate (11-6). Several torsion rollers (11-4) are provided between the inner ring plate (11-1) and the outer ring plate (11-2). Several roller limiting plates (11-5) are provided at both ends of the torsion rollers (11-4). Each roller limiting plate (11-5) is used to limit the two torsion rollers (11-4). A clamp connecting plate (11-6) is provided outside the outer ring plate (11-2). The clamp connecting plate (11-6) is connected to the axial reaction frame (5). It also includes a bottom pier limiting device (9), which includes two bottom pier limiting steel beams (9-2) and hand jacks (9-1). The two bottom pier limiting steel beams (9-2) are connected to the ground beam (12), and at least four hand jacks (9-1) are symmetrically provided on both sides of the two bottom pier limiting steel beams (9-2).

2. The multi-condition testing device for structural members subjected to complex compression-bending-torsion-shear stresses as described in claim 1, characterized in that: The lateral connecting hinge can be a lateral one-way hinge (3-2) or a lateral cross hinge (3-5). When the specimen (7) has only a one-way rotation angle, the lateral connecting hinge is a lateral one-way hinge (3-2); when the specimen (7) has a two-way rotation angle, the lateral connecting hinge is a lateral cross hinge (3-5).

3. The multi-condition testing device for structural members under complex compression-bending-torsion-shear stresses as described in claim 2, characterized in that: The lateral force loading device can be an MTS (3-1), or the lateral force loading device can be a tension / compression jack (3-3). When the lateral force loading device is a tension / compression jack (3-3), one end of the tension / compression jack (3-3) is connected to a lateral connecting hinge on one side, and the other end of the tension / compression jack (3-3) is connected to a lateral force sensor (3-4) and then connected to a lateral connecting hinge on the other side. It also includes a displacement sensor installed on the tension / compression jack (3-3).

4. The multi-condition testing device for structural members under complex compression-bending-torsion-shear stresses as described in claim 3, characterized in that: When the specimen (7) has a unidirectional rotation angle, the axial connecting hinge is a unidirectional hinge; when the specimen (7) has torsional deformation, the axial connecting hinge is a ball joint (6-11).

5. The multi-condition testing device for structural members under complex compression-bending-torsion-shear stresses as described in claim 4, characterized in that: When the specimen (7) has a second-order effect under lateral load, the translational hinge is fixed on the crossbeam of the axial reaction frame (5).

6. The multi-condition testing device for structural members under complex compression-bending-torsion-shear stresses as described in claim 5, characterized in that: The translational hinge includes a top plate buckle (6-1), a top plate (6-2), rollers (6-3), a loading plate (6-4), and upper and lower plate buckles (6-5). The top plate (6-2) is provided with at least four top plate buckles (6-1). The top plate buckles (6-1) are used to fix the axial loading system (6) on the crossbeam of the axial reaction frame (5). The top plate (6-2) is provided with two loading plates (6-4) and several rollers (6-3) between the two loading plates (6-4). The two loading plates (6-4) are connected by at least four upper and lower plate buckles (6-5).

7. A multi-condition testing device for structural members subjected to complex compression-bending-torsion-shear stresses as described in claim 6, characterized in that: The inner ring plate (11-1) of the torsion clamp (11) is locally roughened or a rubber pad is installed inside the inner ring plate (11-1); two adjacent roller limiting plates (11-5) are stacked alternately, and each roller limiting plate (11-5) is limited at the end by a nut to ensure that the bearings of each roller do not tilt or separate during the torsion process.

8. The multi-condition testing device for structural members under complex compression-bending-torsion-shear stresses as described in claim 7, characterized in that: The maximum lateral force and axial force that the lateral reaction frame (1) and axial reaction frame (5) can withstand are both higher than the range of the lateral MTS or tension / compression jack.

9. A multi-condition testing device for structural members subjected to complex compression-bending-torsion-shear stresses as described in claim 8, characterized in that: The crossbeam of the lateral reaction frame (1) has pre-drilled bolt holes for bolting to the lateral connecting hinge of the lateral loading system (3); the crossbeam (4-1) of the specimen (7) has pre-drilled embedded screw holes (4-3) and pre-drilled bolt holes (4-4) for screwing or bolting to the detachable torsion steel arm (4) and the embedded steel component (4-2), respectively; the detachable torsion steel arm (4) has lateral connecting screw holes (4-5) for bolting to the lateral connecting hinge of the lateral loading system (3); the screw is a high-strength screw and the bolt is a high-strength bolt.

10. A test method using the multi-condition test apparatus for structural members subjected to complex compression-bending-torsion-shear stresses as described in any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Installation process. Design and install the ground beam (12) according to the ground anchor size of the test site. Then install the lateral reaction frame (1) and axial reaction frame (5) on the ground beam (12). Restrict the specimen bottom block (8) on the ground beam (12) through the bottom block limiting device (9). Restrict the planar lateral displacement and rotation of the specimen (7) through the hand jack (9-1) on the bottom block limiting device (9). Then install the detachable torsion steel arm (4). Selectively install the torsion clamp (11), lateral loading system (3) and axial loading system (6) according to the measured force type. Step 2, Test process: When only the axial loading system (6) is installed, axial compression and eccentric compression loading can be achieved; when only the lateral loading system (3) is installed, by adjusting the height of the specimen (7), i.e. the shear span ratio, the shear and bending loading of the specimen (7) can be achieved; by rotating the axial reaction frame (5) of the specimen (7) by 180° and setting the action point of the lateral loading system (3) at the geometric center of the specimen (7), the compression-bending, bending-shear, compression-shear and compression-bending-shear coupled loading of the specimen (7) can be achieved; by installing the torsion clamp (11) of the specimen (7), pure torsion and compression-torsion coupled loading can be achieved; by adjusting the position of the lateral loading system (3) on the detachable torsion steel arm (4), i.e. the distance from the lateral load action point to the geometric center of the specimen (7), the bending-torsion, shear-torsion, compression-bending-torsion, compression-shear-torsion and compression-bending-torsion-shear coupled force loading of the specimen (7) can be achieved.

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