A test device suitable for punching shear test and punching shear and bending test of slab-column joint of slab-column structure

Abstract

The present application relates to the technical field of structural test, in particular to a test device suitable for punching shear test and bending-punching test of slab-column joint of slab-column structure. The test device can separately apply bending moment and shear force in two directions of slab-column joint, and can ensure the preset failure mode of slab-column joint. The test device is composed of base, counterforce frame assembly, base, slab-column joint test piece, vertical outrigger assembly, first hinged support, vertical loading device, second hinged support, vertical distribution beam, vertical counterforce beam, first vertical jack, second vertical jack, vertical force sensor, first steel plate, lower horizontal loading device and upper horizontal loading device. The present application provides a new test device for expanding the slab-column joint test of large punching shear ratio and the slab-column joint test of unequal bending moment in two directions, which is very important for further studying the punching shear resistance and bending-punching resistance of slab-column joint.

Description

Technical Field

[0001] This invention relates to the field of structural testing technology, specifically to a testing apparatus suitable for punching shear and bending punching tests of plate-column joints in plate-column structures. Background Technology

[0002] Slab-column structures are structures formed by connecting slabs and columns through joints, offering significant advantages such as reduced floor height, flexible pipe layout, and convenient construction. The slab-column joints are crucial in slab-column structures because they transmit bending moments and shear forces between the slab and column. However, the stress distribution in the slab-column joint area is complex, and there is currently no unified understanding of its mechanical behavior and failure mechanism. Failure modes of slab-column joints include punching shear failure and flexural-punching failure. Punching shear failure occurs suddenly and is a clear example of brittle failure, where the tensile longitudinal reinforcement of the slab has not yielded before failure. Flexural-punching failure is the result of the combined effects of the high-concentration bending and punching shear effects around the column, where the tensile longitudinal reinforcement of the slab near the column yields or is close to yielding before failure.

[0003] When a slab-column structure has different spans but the same load in two perpendicular directions, the slab-column joint will experience unequal bending moments in both directions. For slab-column joints with unequal bending moments in the two directions, the degree of damage and the order of failure of the shear-compression zones in the two directions may differ during loading; that is, the shear-compression zones in both directions may be broken down individually during loading. This can lead to the actual bearing capacity of the slab-column joint being lower than the sum of the estimated contributions of the shear-compression zones on each side to the bearing capacity.

[0004] Domestic and international scholars have conducted extensive experimental research on slab-column joints. However, existing experimental schemes for slab-column joints involve taking a portion of the column and the slab it supports from the slab-column structure for testing, and the planar dimensions of the selected slab are determined based on the location of the inflection point of the slab's bending moment in the slab within the slab-column structure. In existing experimental results, the vast majority of slab-column joint specimens exhibit punching shear failure, while specimens showing flexural-punching failure are rare, and tests on slab-column joints with unequal bending moments in the two directions are even fewer. From a technical perspective, existing experimental schemes cannot guarantee that slab-column joints will experience the predetermined failure mode. Furthermore, when conducting experimental research on slab-column joints with large punching-to-span ratios, the planar dimensions of the slab are large, resulting in high experimental costs and stringent requirements for the experimental site.

[0005] Given the current state of research on slab-column joints in slab-column structures, it is necessary to conduct more experimental research on slab-column joints to ensure the safe application of slab-column structures in practical engineering. Summary of the Invention

[0006] To solve the above problems, the present invention provides a test apparatus for punching shear and bending punching tests of plate-column joints suitable for plate-column structures.

[0007] This invention discloses a test apparatus suitable for punching shear and bending punching tests on slab-column joints of slab-column structures. The apparatus comprises a foundation, a reaction frame assembly, a base, a slab-column joint specimen, a vertical outrigger assembly, a first hinged support, a vertical loading device, a second hinged support, a vertical distribution beam, a vertical reaction beam, a first vertical jack, a second vertical jack, a vertical force sensor, a first steel plate, a lower horizontal loading device, and an upper horizontal loading device. The reaction frame assembly consists of four bases, twelve frame columns, four frame beams, two H-shaped vertical reaction beam supports, connecting steel plates, and connecting... The components are bolted together; the slab-column joint specimen consists of a slab-column joint specimen column, a slab-column joint specimen plate, and longitudinal reinforcement at the top of the slab; the vertical cantilever assembly consists of three cantilever members and a horizontal beam with a row of holes corresponding to the longitudinal reinforcement at the top of the slab; the vertical loading device consists of two first concrete walls, two second concrete walls, eight steel pipes, several fixing bolts, and several fixing steel plates; the reaction frame assembly is vertically fixed to the foundation with eight bolts; the base is vertically fixed to the foundation with four bolts; a square hole is machined at the center of the base; the slab-column joint specimen... The components are placed vertically in the square holes of the base; the four sets of vertical outrigger assemblies are respectively suspended on the top longitudinal reinforcement of the slab and anchored to the end of the slab-column node specimen with nuts; the four sets of first hinge supports are respectively placed vertically on the four sides of the slab-column node specimen; the vertical loading device is placed vertically on the four sets of first hinge supports; the two sets of second hinge supports are respectively placed vertically and centrally on the two first concrete walls of the vertical loading device; a set of vertical distribution beams is placed vertically and centrally on the two sets of second hinge supports; a set of first vertical jacks is placed vertically and centrally on the vertical distribution beams; two The second set of vertical jacks is placed vertically and centrally on the two second concrete walls of the vertical loading device; a set of vertical reaction beams is placed vertically and centrally on the two H-shaped vertical reaction beam supports and anchored to the foundation with eight prestressed threaded steel bars; the lower ends of the three sets of vertical force sensors are respectively tightened to the first steel plate, and the upper ends are respectively abutted against the lower surface of the vertical reaction beams; a lower horizontal loading device is set between the lower opposite sides of the frame column and the corresponding cantilever member, and the outer side of the frame beam and the upper outer side of the corresponding cantilever member are clamped by the upper horizontal loading device.

[0008] The beneficial effects of this invention are:

[0009] This invention enables the application of bending moment and shear force separately in both directions at slab-column joints, thus solving the problem that existing test schemes cannot apply bending moment to slab-column joints independently, and ensuring that the slab-column joint fails in the preset failure mode. Simultaneously, it provides a new test apparatus for expanding slab-column joint tests with large span ratios and slab-column joints with unequal bending moments in two directions, which is crucial for further in-depth research on the punching shear resistance and flexural punching resistance of slab-column joints. Attached Figure Description

[0010] Figure 1 A side view of the test apparatus for punching shear and bending punching tests of plate-column joints applicable to plate-column structures;

[0011] Figure 2 A front view schematic diagram of the test apparatus for punching shear and bending punching tests of plate-column joints applicable to plate-column structures;

[0012] Figure 3 This is an isometric schematic diagram of the base;

[0013] Figure 4 This is an isometric schematic diagram of a plate-column joint specimen;

[0014] Figure 5 This is an isometric schematic diagram of the vertical outrigger assembly;

[0015] Figure 6 This is an isometric schematic diagram of the vertical loading device;

[0016] Figure 7 This is an isometric schematic diagram of the assembled plate-column joint specimen;

[0017] Figure 8 This is an isometric schematic diagram of the lower horizontal loading device;

[0018] Figure 9 This is an isometric schematic diagram of the upper horizontal loading device;

[0019] Figure 10 This is an isometric schematic diagram of the reaction frame assembly;

[0020] Figure 11 This is an isometric schematic diagram of a vertical reaction beam. Detailed Implementation

[0021] Specific Implementation Method 1: This implementation method is described in conjunction with the accompanying drawings. This implementation method provides a test apparatus suitable for punching shear and bending punching tests on slab-column joints of slab-column structures. The apparatus comprises a foundation 0, a reaction frame assembly 1, a base 2, a slab-column joint specimen 3, a vertical outrigger assembly 4, a first hinge support 5, a vertical loading device 6, a second hinge support 7, a vertical distribution beam 8, a vertical reaction beam 9, a first vertical jack 11, a second vertical jack 12, a vertical force sensor 13, a first steel plate 14, a lower horizontal loading device 15, and an upper horizontal loading device 16. The reaction frame assembly 1 consists of four bases 40, twelve frame columns 41, four frame beams 42, and two… The H-shaped vertical reaction beam support 43, connecting steel plate 44, and connecting bolts 45 are composed of: the plate-column joint specimen 3, which consists of a plate-column joint specimen column 17, a plate-column joint specimen plate 18, and a top longitudinal reinforcement 19; the vertical outrigger assembly 4, which consists of three outrigger components 20 and a horizontal beam 21 with a row of holes corresponding to the top longitudinal reinforcement; the vertical loading device 6, which consists of two first concrete walls 22, two second concrete walls 23, eight steel pipes 24, several fixing bolts 25, and several fixing steel plates 26; the reaction frame assembly 1 is vertically fixed to the foundation 0 by eight bolts; the base 2 is vertically fixed to the foundation 0 by four bolts; the base... A square hole is machined at the center of base 2, and the plate-column node specimen 3 is placed vertically in the square hole of base 2; four sets of vertical extension arm assemblies 4 are respectively suspended on the top longitudinal reinforcement 19 of the plate and anchored to the plate end of the plate-column node specimen 3 with nuts; four sets of first hinge supports 5 are respectively placed vertically on the four sides of the plate-column node specimen plate 18; the vertical loading device 6 is placed vertically on the four sets of first hinge supports 5; two sets of second hinge supports 7 are respectively placed vertically and centrally on the two first concrete walls 22 of the vertical loading device 6; a set of vertical distribution beams 8 are placed vertically and centrally on the two sets of second hinge supports 7; a set of first vertical jacks 11 are placed vertically and centrally on the vertical distribution beams 6. On beam 8; two sets of second vertical jacks 12 are respectively placed vertically and centrally on the two second concrete walls 23 of the vertical loading device 6; a set of vertical reaction beams 9 are placed vertically and centrally on the two H-shaped vertical reaction beam supports 43, and are anchored to the foundation 0 by eight prestressed threaded steel bars 10; the lower ends of three sets of vertical force sensors 13 are respectively tightened on the first steel plate 14, and the upper ends are respectively abutted on the lower surface of the vertical reaction beams 9; a lower horizontal loading device 15 is set between the lower opposite sides of the frame column 41 and the corresponding cantilever member 20, and is clamped on the outer side of the frame beam 42 and the upper outer side of the corresponding cantilever member 20 by the upper horizontal loading device 16.

[0022] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the reaction frame assembly 1 consists of four bases 40, twelve frame columns 41, four frame beams 42, two H-shaped vertical reaction beam supports 43, connecting steel plates 44, and connecting bolts 45. The frame columns 41 are arranged vertically in groups of three on a base 40. The four frame beams 42 form a hexagonal frame at the top of the twelve frame columns 41. The ends of adjacent frame beams 42 are connected by connecting steel plates 44 and connecting bolts 45. The H-shaped vertical reaction beam supports 43 are vertically and symmetrically arranged on the hexagonal frame. Everything else is the same as in Specific Implementation Method One.

[0023] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 in that: the plate-column joint specimen 3 consists of a plate-column joint specimen column 17, a plate-column joint specimen plate 18, and a top longitudinal reinforcement 19; the plate-column joint specimen column 17 is vertically positioned at the center of the plate-column joint specimen plate 18, and the top longitudinal reinforcement 19 extends from the end of the plate-column joint specimen plate 18 and has threads at its end. Everything else is the same as in Specific Implementation Method 1.

[0024] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods Two or Three in that the vertical loading device 6 consists of two first concrete walls 22, two second concrete walls 23, a steel pipe 24, fixing bolts 25, and a fixing steel plate 26. The two first concrete walls 22 and the two second concrete walls 23 form a quadrilateral, with a height difference between them. The four corners of the two opposing first concrete walls 22 and the two opposing second concrete walls 23 are connected by steel pipes 24, which are then connected to the walls by fixing bolts 25 and fixing steel plates 26. Everything else is the same as in Specific Implementation Methods Two or Three.

[0025] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods Two to Four in that the lower horizontal loading device 15 consists of a lower horizontal jack 27, a lower force sensor 28, a lower steel roller 29, lower bolts 30, and a lower steel plate 31. The lower horizontal jack 27 is horizontally positioned between two lower steel plates 31. A lower force sensor 28 is installed on the outer side of the top end of the lower horizontal jack 27. The lower force sensor 28 is clamped by a pair of lower steel plates 31, which are locked together by lower bolts 30. Simultaneously, a lower steel roller 29 is installed on the outer side of the pair of lower steel plates 31 according to testing requirements. Everything else is the same as in Specific Implementation Methods Two to Four.

[0026] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods Two to Five in that: the upper horizontal loading device 16 consists of an upper horizontal jack 32, an upper force sensor 33, steel components 34, upper reinforcing bars 35, upper nuts 36, upper steel rollers 37, upper bolts 38, and an upper steel plate 39; two steel components 34 are arranged in parallel, connected at their four corners by upper reinforcing bars 35, and the protruding ends of the upper reinforcing bars 35 are locked by upper nuts 36; an upper steel roller 37 is installed on the inner side of one side of the steel component 34 according to the test requirements, and the upper force sensor 33 is clamped to the inner side of the other side of the steel component 34 by the upper steel plate 39 and fixed by the upper bolts 38; the upper horizontal jack 32 is horizontally arranged between the two upper steel plates 39, and the upper steel plate 39 at the top end of the upper horizontal jack 32 is fixedly connected to the upper steel plate 39 clamping the upper force sensor 33. Everything else is the same as in Specific Implementation Methods Two to Five.

[0027] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods Two to Five in that the vertical reaction beam 9 is composed of a steel beam 46, ear beams 47, reaction beam bolts 48, and stiffening ribs 49; the two ear beams 47 are laterally fixed to the upper surface of the steel beam 46 by the reaction beam bolts 48, and several stiffening ribs 49 are provided on the inner side of the steel beam 46. Everything else is the same as in Specific Implementation Methods Two to Five.

[0028] The beneficial effects of the present invention are verified using the following embodiments:

[0029] Example 1: The installation sequence of the entire test device is as follows: reaction frame assembly, base, plate-column joint specimen, vertical outrigger assembly, lower horizontal loading device, upper horizontal loading device, first hinge support, vertical loading device, second hinge support, vertical distribution beam, first vertical jack, second vertical jack, three sets of vertical force sensors, vertical reaction beam and prestressed threaded steel bars.

[0030] A set of first vertical jacks 11 applies a vertical load in one direction to the vertical distribution beam 8, then transfers the load to two sets of second hinged supports 7, subsequently to the two first concrete walls 22 of the vertical loading device 6, and finally to the two opposite sides of the slab-column joint specimen 18 in one direction. Two sets of second vertical jacks 12 apply a vertical load in another direction to the two second concrete walls 23 of the vertical loading device 6, then transfer the load to the two opposite sides of the slab-column joint specimen 18 in the other direction. This applies shear force and bending moment to the slab-column joint in two directions. Twelve sets of lower horizontal loading devices 15 and twelve sets of upper horizontal loading devices 16 apply inward and outward horizontal thrusts to the lower and upper parts of the outrigger members 20 of the four sets of vertical outrigger assemblies 4, respectively. This applies bending moment to the slab-column joint in two directions. By continuously adjusting the magnitude of the vertical load and horizontal thrust, and based on the strain readings of the tensile longitudinal reinforcement of the slab, punching shear failure or bending punching failure is caused at the slab-column joint.

[0031] The above embodiments, through the design of a series of test devices, enable the application of bending moment and shear force separately in two directions to the plate-column joint of the plate-column structure, thereby providing a new test scheme for punching shear test and bending punching test of plate-column joint. It can also be used for plate-column joints with unequal bending moments in two directions. The structure is simple and easy to implement.

Claims

1. A test apparatus suitable for punching shear and bending punching tests on plate-column joints of plate-column structures, characterized in that... The test apparatus for punching shear and bending punching tests of slab-column joints suitable for slab-column structures consists of a foundation (0), a reaction frame assembly (1), a base (2), a slab-column joint specimen (3), a vertical outrigger assembly (4), a first hinge support (5), a vertical loading device (6), a second hinge support (7), a vertical distribution beam (8), a vertical reaction beam (9), a first vertical jack (11), a second vertical jack (12), a vertical force sensor (13), a first steel plate (14), a lower horizontal loading device (15), and an upper horizontal loading device (16). The reaction frame assembly (1) consists of four bases (40), twelve frame columns (41), four frame beams (42), two H-shaped vertical reaction beam supports (43), and connections. The steel plate (44) and connecting bolts (45) are used; the plate-column joint specimen (3) is composed of a plate-column joint specimen column (17), a plate-column joint specimen plate (18), and a top longitudinal reinforcement (19); the vertical outrigger assembly (4) is composed of three outrigger components (20) and a beam (21) with a row of holes corresponding to the top longitudinal reinforcement; the vertical loading device (6) is composed of two first concrete walls (22), two second concrete walls (23), eight steel pipes (24), several fixing bolts (25), and several fixing steel plates (26); the reaction frame assembly (1) is vertically fixed to the foundation (0) by eight bolts; the base (2) is vertically fixed to the foundation (0) by four bolts; the center position of the base (2) is... The plate-column node specimen (3) is vertically placed in the square hole of the base (2); four sets of vertical outrigger assemblies (4) are respectively suspended on the top longitudinal reinforcement (19) of the plate and anchored to the plate end of the plate-column node specimen (3) with nuts; four sets of first hinge supports (5) are respectively vertically placed on the four sides of the plate-column node specimen plate (18); the vertical loading device (6) is vertically placed on the four sets of first hinge supports (5); two sets of second hinge supports (7) are respectively vertically centered on the two first concrete walls (22) of the vertical loading device (6); one set of vertical distribution beams (8) is vertically centered on the two sets of second hinge supports (7); one set of first vertical jacks (11) is vertically centered on the vertical distribution beams (8). Above; two sets of second vertical jacks (12) are placed vertically and centrally on the two second concrete walls (23) of the vertical loading device (6); a set of vertical reaction beams (9) are placed vertically and centrally on the two H-shaped vertical reaction beam supports (43) and anchored to the foundation (0) with eight prestressed threaded steel bars (10); the lower ends of three sets of vertical force sensors (13) are respectively tightened on the first steel plate (14) and the upper ends are respectively pressed against the lower surface of the vertical reaction beam (9); a lower horizontal loading device (15) is set between the lower opposite sides of the frame column (41) and the corresponding outrigger member (20), and clamped by the upper horizontal loading device (16) on the outer side of the frame beam (42) and the upper outer side of the corresponding outrigger member (20).

2. The test apparatus for punching shear and bending punching tests of plate-column joints suitable for plate-column structures according to claim 1, characterized in that... The reaction frame assembly (1) consists of four bases (40), twelve frame columns (41), four frame beams (42), two H-shaped vertical reaction beam supports (43), connecting steel plates (44), and connecting bolts (45). The frame columns (41) are arranged vertically in groups of three on one base (40), and the four frame beams (42) form a hexagonal frame at the top of the twelve frame columns (41). The ends of adjacent frame beams (42) are connected by connecting steel plates (44) and connecting bolts (45). The H-shaped vertical reaction beam supports (43) are vertically and symmetrically arranged on the hexagonal frame.

3. The test apparatus for punching shear and bending punching tests of plate-column joints suitable for plate-column structures according to claim 1, characterized in that... The plate-column joint specimen (3) consists of a plate-column joint specimen column (17), a plate-column joint specimen plate (18), and a top longitudinal reinforcement (19). The plate-column joint specimen column (17) is vertically set at the center of the plate-column joint specimen plate (18), and the top longitudinal reinforcement (19) extends from the end of the plate-column joint specimen plate (18) and is threaded at the end.

4. The test apparatus for punching shear and bending punching tests of plate-column joints suitable for plate-column structures according to claim 1, characterized in that... The vertical loading device (6) consists of two first concrete walls (22), two second concrete walls (23), a steel pipe (24), fixing bolts (25), and a fixing steel plate (26). The two first concrete walls (22) and the two second concrete walls (23) form a quadrilateral. There is a height difference between the first concrete walls (22) and the second concrete walls (23). The four corners of the two oppositely arranged first concrete walls (22) and the two oppositely arranged second concrete walls (23) are connected by steel pipes (24). The steel pipes (24) are connected to the wall by fixing bolts (25) and fixing steel plates (26).

5. The test apparatus for punching shear and bending punching tests of plate-column joints suitable for plate-column structures according to claim 1, characterized in that... The lower horizontal loading device (15) consists of a lower horizontal jack (27), a lower force sensor (28), a lower steel roller (29), a lower bolt (30), and a lower steel plate (31). The lower horizontal jack (27) is horizontally positioned between two lower steel plates (31). A lower force sensor (28) is provided on the outer side of the top end of the lower horizontal jack (27). The lower force sensor (28) is clamped by a pair of lower steel plates (31). The pair of lower steel plates (31) are locked together by the lower bolt (30). At the same time, a lower steel roller (29) is installed on the outer side of the pair of lower steel plates (31) according to the test requirements.

6. The test apparatus for punching shear and bending punching tests of plate-column joints suitable for plate-column structures according to claim 1, characterized in that... The upper horizontal loading device (16) consists of an upper horizontal jack (32), an upper force sensor (33), steel components (34), upper reinforcing bars (35), upper nuts (36), upper steel rollers (37), upper bolts (38), and an upper steel plate (39); two steel components (34) are arranged in parallel, and are connected at the four corners by upper reinforcing bars (35), with the protruding ends of the upper reinforcing bars (35) locked by upper nuts (36); one side of the steel component ( The inner side of 34) is equipped with an upper steel roller (37) according to the test requirements. The upper force sensor (33) is clamped to the inner side of the other steel component (34) by the upper steel plate (39) and fixed by the upper bolt (38). The upper horizontal jack (32) is horizontally set between the two upper steel plates (39). The upper steel plate (39) at the top end of the upper horizontal jack (32) is fixedly connected to the upper steel plate (39) that clamps the upper force sensor (33).

7. The test apparatus for punching shear and bending punching tests of plate-column joints suitable for plate-column structures according to claim 1, characterized in that... The vertical reaction beam (9) is composed of a steel beam (46), ear beams (47), reaction beam bolts (48), and stiffening ribs (49); the two ear beams (47) are horizontally fixed to the upper surface of the steel beam (46) by the reaction beam bolts (48), and a number of stiffening ribs (49) are provided on the inner side of the steel beam (46).

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