CN114813307B - Transverse bending resistance test method and test equipment for steel-concrete composite beam connecting key - Google Patents

Abstract

The present invention belongs to the technical field of bridge engineering, and more particularly to a method for testing the transverse bending performance of a steel-concrete composite beam connection key, and a testing device thereof. The present invention achieves the purpose of effectively testing the tensile bending and compressive bending performance of the connection key by first welding the connection key, then pouring the concrete slab, then pressing the concrete slab down at the end, and finally pressing the concrete slab down in the middle. In addition, the testing equipment of the present invention has a structure including a jack body, an extension bolt, a fixing ring unit, a U-shaped suspension frame unit, a support frame unit, a Y-shaped pull rope unit, and a radial groove, so as to achieve the purpose of stable and efficient operation of the tensile bending and compressive bending performance testing.

Description

A test method for the transverse bending performance of the connecting key of a steel-concrete composite beam and its test equipment

Technical Field

The invention belongs to the technical field of bridge engineering, and in particular relates to a transverse bending performance test method of a steel-concrete composite beam connecting key, and a test device thereof.

Background Art

Steel-concrete composite beam connector refers to the shear connector used in steel-concrete composite beams, that is, one end is welded or screwed to the steel, and the other end is fixed by concrete pouring. For the connector, one of the most important performance parameters is the transverse bending performance. After all, there will always be a small transverse misalignment between the steel and the concrete slab. Therefore, before the connector is put into use, its transverse bending performance must be tested.

In addition, the lateral bending resistance includes two aspects, namely, pulling upward at an angle, which is tensile bending, and pressing downward at an angle, which is compressive bending. Therefore, the specific test method and equipment must ensure that the actions of pulling upward at an angle and pressing downward at an angle are stable and reliable.

A Chinese utility model patent with patent announcement number CN214408475U and announcement date 2021.10.15 discloses a device for detecting the bending resistance of a steel-concrete composite beam connection, including an equipment body, an inverted hydraulic cylinder is fixedly arranged at the middle position of the uppermost end of the equipment body, a pressing device is fixedly arranged at the uppermost end of the telescopic rod of the hydraulic cylinder, a controller is fixedly arranged at the upper position on the right side of the equipment body, and a slideway is provided in the middle of the left and right sides of the upper surface of the workbench of the equipment body, a slider is slidably arranged inside the slideway, and the upper end surface of the slider is fixedly connected to the lower surface of the moving seat.

However, during use, it is not difficult to find that the detection device in this utility model patent has at least the following three shortcomings.

First, only the compression bending performance of the connector can be tested, but not its tension bending performance.

Second, the actual use environment of the connector cannot be simulated. The bending action is not caused by the misalignment between the concrete slab and the steel, and the final bending performance data is unreliable.

Third, the pressure of the downward pressing action is too great, which may directly cause local penetration, damage, and deformation of the connector before it is bent. This is harmful and is not conducive to detecting its overall bending performance.

So in summary, there is an urgent need for a more realistic, reliable, stable and efficient transverse bending performance test method and equipment to detect the performance and quality of the connecting keys of steel-concrete composite beams.

Summary of the invention

The present invention provides a method for testing the transverse bending performance of a steel-concrete composite beam connecting key, which can achieve the purpose of effectively testing the tensile bending and compressive bending performance of the connecting key by first welding the connecting key, then pouring a concrete slab, then pressing the concrete slab at the end, and finally pressing the concrete slab in the middle.

In addition, the present invention also provides a transverse bending performance test equipment for the connecting key of a steel-concrete composite beam, whose structure includes a jack body, an extension bolt, a fixing ring unit, a U-shaped suspension frame unit, a support frame unit, a Y-shaped rope unit and a radial groove, so as to achieve the purpose of stable and efficient operation of tensile bending and compressive bending performance detection.

The technical solution adopted by the present invention to solve the above problem is: a method for testing the transverse bending performance of a steel-concrete composite beam connecting key, which comprises the following steps in sequence:

S1. Weld connecting keys on the upper surfaces of the two support plates;

S2, pouring a concrete slab on the support plate, and pouring and fixing both sets of connecting keys;

S3. Press down on the two ends of the concrete slab located outside the two sets of connection keys to test the tensile and bending properties of the two sets of connection keys;

S4. Perform a downward pressing operation at a position between the two sets of connecting keys on the concrete slab to simultaneously test the compression and bending resistance of the two sets of connecting keys.

A further preferred technical solution is that the concrete slab is made entirely of cast-in-place concrete, or comprises three prefabricated concrete slabs and two cast-in-place concrete slabs, and the two sets of connecting keys are cast and fixed by the two cast-in-place concrete slabs respectively.

A transverse bending performance test device for a steel-concrete composite beam connecting key, comprising an inverted jack body and an extension bolt arranged on the shaft of the jack body, a fixing ring unit sleeved on the extension bolt, a U-shaped suspension frame unit arranged between two aligned and separated concrete precast panels and used for filling concrete and making cast-in-place concrete panels, a support frame unit for welding the connecting key, and two Y-shaped pull rope units arranged on the fixing ring unit and respectively used for obliquely pulling the two U-shaped suspension frame units.

A further preferred technical solution is that the U-shaped suspension frame unit includes a U-shaped plate with both ends respectively inserted into the concrete precast panels, a mounting hole arranged on the bottom plate of the U-shaped plate and used to pass the connecting key upward, and two suspension holes respectively arranged on the two side plates of the U-shaped plate and used to insert and clamp the Y-shaped pull rope unit.

A further preferred technical solution is that the U-shaped suspension frame unit also includes a friction plate arranged at a side position on the inner bottom surface of the U-shaped plate and used for anti-slip fixation on the lower surface of the middle precast concrete plate.

A further preferred technical solution is that the Y-shaped rope pulling unit includes a main rope arranged on the fixing ring unit, two branch ropes with one end arranged on the main rope, and an arc-shaped block arranged on the branch rope and fixed on the inner side after being inserted into the suspension hole.

A further preferred technical solution is that the Y-shaped rope pulling unit further comprises an insert plate arranged on the inner annular surface of the arc-shaped block, and a radial groove for mounting the insert plate is provided on the annular surface of the circular tail of the extension bolt.

A further preferred technical solution is that the arc block is a 1/4 ring, and after the four arc blocks are aligned into a ring, the lower surface is flush with the lower surface of the circular tail of the extended bolt, so as to increase the downward pressure surface area of the jack body.

A further preferred technical solution is that the fixing ring unit includes a circular ring body which is sleeved on the extension bolt rod, and an annular rope body groove which is arranged on the upper surface of the circular ring body and is used to accommodate the main rope and the branch rope when the arc block is idle.

A further preferred technical solution is that the support frame unit includes a base plate, a support column arranged on the upper surface of the base plate, and a support plate arranged on the upper end surface of the support column and the upper surface of which is used for welding connecting keys.

The present invention has the following advantages.

First, the test device constructed by the support plate, connecting key and concrete slab is reasonable and effective, and the simulated tensile and compressive conditions of the connecting key are highly realistic, ensuring that the final bending performance data is more realistic and reliable.

Second, the two ends and the middle of the same concrete slab are pressed down successively to ensure that the tensile bending and compressive bending operations are convenient and effective.

Third, the concrete slab includes three sections of prefabricated slabs and two sections of cast-in-place slabs, ensuring that the overall structure of the connecting key plus the concrete slab is prepared more quickly and efficiently.

Fourth, before pressing down, the test equipment can provide support and mold for the cast-in-place slab to ensure that its casting operation is more convenient, simple, stable and safe. The U-shaped suspension unit as a mold will not affect the active bending deformation of the concrete slab.

Fifth, when the test equipment is used for downward pressure, the Y-shaped pull rope unit can be stably stored, and together with the extension bolt, it forms a larger downward pressure surface to prevent the concrete slab from being crushed by excessive pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the pressing operation of the connecting key in the present invention during the tensile bending test.

FIG. 2 is a schematic diagram of the pressing operation of the connecting key during the compression bending test in the present invention.

FIG3 is a schematic diagram of the operation of the test equipment of the present invention when pouring a cast-in-place concrete slab.

FIG. 4 is a schematic diagram of the position structure of the Y-shaped pull rope unit in the present invention.

FIG. 5 is a schematic diagram of the operation of the arc block and the extension bolt acting as the lower pressure surface in the present invention.

FIG. 6 is a schematic structural diagram of a U-shaped suspension frame unit in the present invention.

FIG. 7 is a schematic diagram of the operation of the arc block being clamped and fixed on the suspension hole to suspend the entire U-shaped suspension frame unit in the present invention.

FIG. 8 is a schematic diagram of the position structure of the fixed ring unit in the present invention.

In the accompanying drawings, the components represented by each reference numeral are as follows: connecting key a, concrete slab b, precast concrete slab b1, cast-in-place concrete slab b2, jack body 11, extension bolt 12, fixing ring unit 1, U-shaped suspension frame unit 2, support frame unit 3, Y-shaped pull rope unit 4, U-shaped plate 201, mounting hole 202, suspension hole 203, friction plate 204, main rope 401, branch rope 402, arc block 403, insertion plate 404, radial groove 5, circular ring body 101, annular rope body groove 102, bottom plate 301, support column 302, support plate 303.

DETAILED DESCRIPTION

The following descriptions are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention.

As shown in Figures 1-8, a method for testing the transverse bending performance of a steel-concrete composite beam connector includes the following steps in sequence:

S1. Welding connection keys a on the upper surfaces of the two support plates 303;

S2, pouring a concrete slab b on the support plate 303, and pouring and fixing the two sets of connecting keys a;

S3, pressing down respectively at the two ends of the concrete slab b located outside the two sets of connecting keys a, so as to respectively detect the tensile and bending properties of the two sets of connecting keys a;

S4. Perform a downward pressing operation at a position between the two groups of connecting keys a on the concrete slab b to simultaneously detect the compression and bending resistance of the two groups of connecting keys a.

In the prior art, the installation and use environment of the connection key a is that one end is welded or screwed to steel and the other end is inserted into concrete. Therefore, in this embodiment, the force of bending the connection key a is transmitted through the concrete plate b, rather than directly setting a clamping device on the connection key a, so that the final transverse bending performance data can be guaranteed to be more convincing, more real and reliable.

Among them, when pressing down on one end of the concrete slab b, the connecting key a far away from one side can be deemed to have no effect, so the other end needs to be pressed down again. When pressing down in the middle of the concrete slab b, combined with its relatively short and appropriate length, it can be determined that the connecting keys a on both sides have been effectively tested for compressive bending.

In addition, after two groups of connecting keys a have completed the tensile bending and compressive bending tests, the welding ends of the connecting keys a can be released. If the connecting keys a cannot meet the continuous test strength of first tensile bending and then compressive bending, only one item can be tested for a batch of connecting keys.

Finally, the tensile bending and compressive bending data or grades of the connecting key a are measured and analyzed according to the principles specified in the prior art.

The concrete slab b is made entirely of cast-in-place concrete, or includes three prefabricated concrete slabs b1 and two cast-in-place concrete slabs b2, and the two sets of connecting keys a are cast and fixed by the two cast-in-place concrete slabs b2 respectively.

In this embodiment, the concrete slab b is preferably a steel-concrete structure and can be cast in situ. If a prefabrication and cast-in-situ method is adopted, the cast-in-situ end of the concrete prefabricated slab b1 needs to extend a certain length of steel bars to ensure that the cast-in-situ slab can be combined with the prefabricated slab with greater strength.

A lateral bending performance test device for a steel-concrete composite beam connecting key, comprising an inverted jack body 11, and an extension bolt 12 arranged on the shaft of the jack body 11, and also comprising a fixing ring unit 1 sleeved on the extension bolt 12, a U-shaped suspension frame unit 2 arranged between two aligned and separated concrete precast panels b1 and used for filling concrete to prepare a cast-in-place concrete panel b2, a support frame unit 3 for welding a connecting key a, and two Y-shaped rope units 4 arranged on the fixing ring unit 1 and respectively used for obliquely pulling the two U-shaped suspension frame units 2.

In this embodiment, the test equipment adopts a test method of three precast concrete panels b1 plus two cast-in-place concrete panels b2. Its general usage and advantages are as follows.

First, a connection key a is welded or screwed on the upper surface of the support frame unit 3 , and the U-shaped suspension frame unit 2 itself has a hole for the connection key a to be inserted and temporarily placed on the support frame unit 3 .

Second, the Y-shaped pull rope unit 4 passes through the U-shaped suspension frame unit 2 to suspend it, and then there are a total of three precast concrete panels b1, one of which is located between the two U-shaped suspension frame units 2, and the other two are respectively located on the outsides of the two precast concrete panels b1. The ends of the three precast concrete panels b1 are inserted into the U-shaped suspension frame unit 2 to a depth of about 20% of their own length. Finally, the three precast concrete panels b1 plus the two U-shaped suspension frame units 2 are fixed in the air about 5 cm above the upper surface of the support frame unit 3.

Third, add concrete into the two U-shaped suspension frame units 2 and keep them there until they solidify to form a cast-in-place concrete slab b2. At this time, the U-shaped suspension frame units 2 can be left on the cast-in-place concrete slab b2 or removed after being broken, which will not affect the test operation.

Fourthly, the jack body 11 follows its own sliding base, stays at the end and the middle of the concrete slab b and presses down respectively, so as to complete the entire tensile bending and compressive bending test operations and obtain the required transverse bending performance data.

Fifth, the welding part at the lower end of the connection key a is released, and the connection key a and the concrete slab b are completely removed. After the whole is crushed, the concrete block or steel bar and other materials can be reused. In this way, a complete connection key transverse bending performance test is completed.

Among them, the connecting key a includes bolts, steel bars, steel rods and angle steels.

The U-shaped suspension frame unit 2 includes a U-shaped plate 201 with both ends respectively inserted into the concrete precast plate b1, a mounting hole 202 arranged on the bottom plate of the U-shaped plate 201 and used to pass the connecting key a upward, and two suspension holes 203 respectively arranged on the two side plates of the U-shaped plate 201 and used to insert and clamp and fix the Y-shaped pull rope unit 4.

In this embodiment, the U-shaped plate 201 is made of common rubber or plastic, and the mounting hole 202 is a circular hole. A small amount of concrete may leak from the circular hole, which does not affect the forming of the cast-in-place concrete slab b2.

In addition, the shape of the suspension hole 203 is circular or square, ensuring that the engaging portion of the Y-shaped pull rope unit 4 can enter, but also having an engaging angle, so that the U-shaped plate 201 can be suspended and released.

The U-shaped suspension frame unit 2 further includes a friction plate 204 which is arranged at a side position on the inner bottom surface of the U-shaped plate 201 and is used for anti-slip fixation on the lower surface of the middle precast concrete plate b1.

In this embodiment, when the Y-shaped pull rope unit 4 suspends and pulls the U-shaped plate 201, the pulling force is oblique, and the vertical component of the force is a useful force, which can pull up the entire concrete plate b in mid-air, but the lateral component of the force is a harmful force, which will cause the U-shaped plate 201 to slip on the upper surface of the precast concrete plate b1. Therefore, the friction plate 204 made of ordinary soft rubber material is provided to ensure that the U-shaped plate 201 stably spans the two precast concrete plates b1.

Of course, the jack body 11 plus the extension bolt 12 cannot only have the function of lifting downward, but also must ensure that it will not be pulled downward. Therefore, a more stable and effective approach is to set the jack body 11 as a threaded rotary lifting device to ensure that the extension bolt 12 can stably suspend the weight of the entire concrete slab b.

The Y-shaped pull rope unit 4 includes a main rope 401 arranged on the fixing ring unit 1, two branch ropes 402 with one end arranged on the main rope 401, and an arc block 403 arranged on the branch rope 402 and fixed inside after being inserted into the suspension hole 203.

In this embodiment, the Y-shaped pull rope unit 4 has two usage states, namely, it needs to be untied and suspended before pouring the concrete cast-in-place slab b2 until it is completely solidified, and after solidification, it can be folded upward and enter an idle state.

The overall radial size of the arc block 403 is smaller than the opening size of the suspension hole 203, ensuring that the arc block 403 can be inserted into the suspension hole 203 in the chord direction and cannot be pulled out of the suspension hole 203 in the radial direction, so as to ensure stable suspension and release.

Finally, the two main ropes 401 are symmetrical on the fixing ring unit 1, and the two branch ropes 402 are also symmetrical on the main rope 401, ensuring that the entire suspension structure is more stable.

The Y-shaped pull rope unit 4 also includes an insert plate 404 arranged on the inner annular surface of the arc block 403, and a radial groove 5 for installing the insert plate 404 is provided on the annular surface of the circular tail of the extension bolt 12. The arc block 403 is a 1/4 circular ring, and the lower surface of the four arc blocks 403 is flush with the lower surface of the circular tail of the extension bolt 12 after being aligned into a circular ring, so as to increase the downward pressure surface area of the jack body 11.

In this embodiment, if the circular tail of the extension bolt 12 has a relatively small area, if the concrete slab b is pressed down directly, there may be a problem that the pressure is insufficient but the concrete has been crushed. Therefore, when the arc block 403 is idle, the four arc blocks 403 are formed into a complete circular ring, and then the insertion plate 404 is inserted into the radial groove 5 to form a coplanar larger circular supporting surface together with the circular tail of the extension bolt 12 to ensure sufficient pressure strength and relatively small pressure. After all, the bending test requires pressure value, not pressure value.

The circular tail of the extension bolt 12 is a rotational type with a cross pattern on the circular surface, rather than an external hexagonal shape, so it can ensure that it is perfectly spliced with the four arc blocks 403 to form a larger circle.

The fixing ring unit 1 includes a circular ring body 101 which is sleeved on the rod of the extension bolt 12, and an annular rope body groove 102 which is arranged on the upper surface of the circular ring body 101 and is used to receive the main rope 401 and the branch rope 402 when the arc block 403 is idle.

In this embodiment, after the concrete slab b is solidified and the pressing operation is carried out, the arc block 403 is installed on the extension bolt 12. At this time, the main rope 401 and the branch rope 402 will be idle and hang down. Therefore, the annular rope body groove 102 is provided to accommodate these rope bodies, waiting for the next batch of connecting keys a to be reactivated.

The support frame unit 3 includes a bottom plate 301, a support column 302 disposed on the upper surface of the bottom plate 301, and a support plate 303 disposed on the upper end surface of the support column 302 and the upper surface of which is used for welding the connection key a.

In this embodiment, the entire material of the support frame unit 3 is steel, and the upper surface of the support plate 303 is used for welding the connection key a, or is provided with an internal thread ring for screwing the connection key a.

Finally, the number of the support frame units 3 is two, and multiple rows and columns of connection keys a can be set on a single support plate 303 at one time.

The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various modifications can be made within the knowledge of ordinary technicians in the technical field without departing from the purpose of the present invention. These are all non-creative modifications and are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims (6)

1. A transverse bending performance test device for a steel-concrete composite beam connecting key, comprising an inverted jack body (11) and an extension bolt (12) arranged on the shaft of the jack body (11), characterized in that it also includes a fixing ring unit (1) sleeved on the extension bolt (12), a U-shaped suspension frame unit (2) arranged between two aligned and separated concrete precast panels (b1) and used for filling concrete to prepare a cast-in-place concrete panel (b2), a support frame unit (3) for welding a connecting key (a), and two Y-shaped pull rope units (4) arranged on the fixing ring unit (1) and used for obliquely pulling the two U-shaped suspension frame units (2) respectively, The U-shaped suspension frame unit (2) comprises a U-shaped plate (201) with two ends respectively inserted into the concrete precast plate (b1), a mounting hole (202) provided on the bottom plate of the U-shaped plate (201) and used for passing the connecting key (a) upward, and two suspension holes (203) respectively provided on two side plates of the U-shaped plate (201) and used for inserting and locking the Y-shaped pull rope unit (4) for fixing. The U-shaped suspension frame unit (2) further comprises a friction plate (204) arranged at a side position on the inner bottom surface of the U-shaped plate (201) and used for anti-slip fixation on the lower surface of the middle precast concrete plate (b1). 2. A transverse bending performance test device for a steel-concrete composite beam connecting key according to claim 1, characterized in that: the Y-shaped pull rope unit (4) includes a main rope (401) arranged on the fixing ring unit (1), two branch ropes (402) with one end arranged on the main rope (401), and an arc block (403) arranged on the branch rope (402) and fixed on the inner side after being inserted into the suspension hole (203). 3. A transverse bending performance test device for a steel-concrete composite beam connecting key according to claim 2, characterized in that: the Y-shaped rope unit (4) also includes an insertion plate (404) arranged on the inner annular surface of the arc block (403), and a radial groove (5) for mounting the insertion plate (404) is provided on the annular surface of the circular tail of the extension bolt (12). 4. A transverse bending performance test device for a steel-concrete composite beam connecting key according to claim 3, characterized in that: the arc block (403) is a 1/4 ring, and after the four arc blocks (403) are aligned into a ring, the lower surface is flush with the lower surface of the circular tail of the extension bolt (12), so as to increase the downward pressure surface area of the jack body (11). 5. A transverse bending performance test device for a steel-concrete composite beam connecting key according to claim 2, characterized in that: the fixing ring unit (1) comprises a circular ring body (101) sleeved on the rod of the extension bolt (12), and an annular rope body groove (102) arranged on the upper surface of the circular ring body (101) and used to receive the main rope (401) and the branch rope (402) when the arc block (403) is idle. 6. A transverse bending performance test equipment for steel-concrete composite beam connecting keys according to claim 1, characterized in that: the support frame unit (3) includes a base plate (301), a support column (302) arranged on the upper surface of the base plate (301), and a support plate (303) arranged on the upper end surface of the support column (302) and the upper surface of which is used for welding the connecting key (a).