Empty steel pipe axial compression test device for internal local lateral pressurization based on water bag

Abstract

The utility model discloses an empty steel pipe axial compression test device for internal local lateral pressurization based on a water bag. The empty steel pipe axial compression test device comprises a loading base plate, a pressurization system and a supporting mechanism, the supporting mechanism comprises a square steel pipe, an upper end plate, a lower end plate and a water bag, the upper end plate and the lower end plate are arranged at the upper end and the lower end of the square steel pipe respectively, and the loading base plate is fixed to the upper end plate; steel plate supporting plates are arranged on the four inner side walls of the square steel pipe, water bag separation arc-shaped plates are fixed to the sides, away from the inner side walls of the square steel pipe, of the steel plate supporting plates, the inner side walls of the square steel pipe, the water bag separation arc-shaped plates, the upper end plate and the lower end plate form a pressurization cavity used for containing a water bag, and the water bag is placed in the pressurization cavity. The water bag is connected with the pressurizing system; when the water bag is pressurized, the water bag abuts against the four corner angle parts of the square steel pipe, and a gap is formed between the upper end of the water bag and the upper end plate. According to the utility model, experimental data can be obtained more accurately, and verification is provided for theoretical models and numerical simulation.

Description

TECHNICAL FIELD

[0001] The utility model relates to square steel pipe local buckling test device, concretely relates to a kind of empty steel pipe axial compression test device based on water bag internal local lateral pressure. BACKGROUND

[0002] With the rapid economic growth, the construction demand of high-rise and super high-rise building promotes steel-concrete composite component to become the mainstream choice in structural design, and common component form includes steel pipe concrete column and steel plate concrete composite shear wall etc.. These components realize lightweight and strengthening of structure, and also introduce new engineering challenge. Especially, with the application of high-strength concrete and steel, the width-thickness ratio of outer steel plate increases, which leads to the increasingly prominent problem of local buckling of steel plate, and this phenomenon has attracted high attention of engineering field. The requirement of engineering economy makes the design of steel-concrete composite component usually require to maximize the mechanical properties of steel and concrete, especially the yield strength of steel. In terms of structural safety, the problem of local buckling of steel plate may cause premature failure of component and even overall damage, leading to serious consequences and disaster. Therefore, the research on local buckling of steel plate in composite structure is crucial to meet the requirements of engineering economy and structural safety.

[0003] At present, the technical field has preliminarily studied the local buckling performance of steel pipe concrete column, and the research mainly focuses on theoretical analysis and finite element numerical simulation. However, most of the existing researches still stay in the theoretical stage, and lack of experimental data support. This limitation is mainly due to the lack of specially designed experimental device to simulate the local buckling behavior of steel plate in steel pipe concrete column. The existing test research method has many shortcomings, such as inaccurate loading method, failure to fully consider the influence of concrete lateral pressure, inaccurate simulation of boundary conditions, etc., which seriously restricts the progress of in-depth research on local buckling performance of steel-concrete composite structure. UTILITY MODEL CONTENT

[0004] The utility model aims at overcoming the deficiencies of the above prior art, and provides an empty steel pipe axial compression test device based on water bag internal local lateral pressure. The empty steel pipe axial compression test device based on water bag internal local lateral pressure can accurately obtain experimental data, provide verification for theoretical model and numerical simulation, and thus promote the theoretical research on local buckling performance of steel-concrete composite structure and steel structure.

[0005] The utility model discloses a purpose is realized through following technical scheme: this based on the inside local lateral pressure of water bag empty steel pipe axial test device, including loading backing plate, pressurizing system and support mechanism, the support mechanism includes square steel pipe, upper end plate, lower end plate and water bag, upper end plate and lower end plate set up respectively in the upper end and lower end of square steel pipe, loading backing plate is fixed in upper end plate, four inner side walls of square steel pipe all are equipped with steel support plate, the steel support and the inner side wall of square steel pipe fixed with water bag separation arc plate on one side, the inner side wall of square steel pipe, water bag separation arc plate, upper end plate and lower end plate form the pressurizing cavity for placing water bag, water bag is placed in pressurizing cavity, and water bag is connected with pressurizing system, when water bag is pressurized, water bag is against four edge parts of square steel pipe, and there is gap between the upper end of water bag and upper end plate.

[0006] Preferably, the width of the steel plate support plate is less than the width of the inner side wall of the square steel pipe, and the steel plate support plate is tightly pressed in the middle of the corresponding inner side wall of the square steel pipe.

[0007] Preferably, a water bag cover plate is arranged between the water bag and the upper end plate.

[0008] Preferably, the pressurizing system comprises a water inlet pipe, a water outlet pipe, a water tank, a variable frequency water pump and a control box, the water inlet pipe and the water outlet pipe are connected with the water bag, the water inlet pipe and the water outlet pipe are connected with the water tank through a first pipeline and a second pipeline respectively, valves are arranged on the first pipeline and the second pipeline, the variable frequency water pump is installed on the first pipeline and located between the water tank and the valve, and the variable frequency water pump is connected with the control box.

[0009] Preferably, a pressure gauge is arranged on the first pipeline, the pressure gauge is located between the valve and the water inlet pipe, and the pressure gauge is connected with the control box.

[0010] Preferably, the loading backing plate comprises an upper backing plate, a lower backing plate and intersecting stiffening ribs, the upper backing plate is connected with the lower backing plate through the intersecting stiffening ribs, the lower backing plate is fixed on the upper end plate, and the backing plate is provided with a slot matched with the water inlet pipe and the water outlet pipe.

[0011] Preferably, an upper stiffening rib is fixed between the upper end plate and the square steel pipe, and a lower stiffening rib is fixed between the lower end plate and the square steel pipe.

[0012] Compared with the prior art, the utility model has the following advantages:

[0013] 1. The utility model discloses a water bag is arranged in square steel pipe, and through the water bag separation arc plate, the water bag pressurization area is limited in the edge part of square steel pipe, to realize the steel pipe concrete steel plate local buckling performance for research, can realize the stress performance of steel pipe of various materials under the combined action of axial force and different size lateral force, and it has important significance to promote the research in the field, and the device of the utility model can more accurately obtain experimental data, provides the verification for theoretical model and numerical simulation, thereby promotes the theoretical research of steel - concrete composite structure and steel structure local buckling performance.

[0014] 2. The utility model discloses a support mechanism can be divided to the angle area that needs to exert lateral pressure in the steel pipe, realize the adjustable position of the area of steel plate that receives lateral pressure, and provide rigid support to the middle part of steel pipe and prevent the inward buckling of steel plate.

[0015] 3. The internal support system of the utility model can independently add axial water pressure in the pressurization system, and the axial force size of the press machine is not influenced during the test, and the trouble of data processing after the test is saved.

[0016] 4. The utility model discloses a pressurization system adopts high-precision frequency conversion controller and frequency conversion water pump, and the digital display pressure gauge can realize the real-time observation and accurate control of the internal pressure of water bag, realize the adjustable size of the lateral pressure of steel plate.

[0017] 5. The utility model discloses a device, accurately determine the relationship between the water belt pressure and the simulated steel plate transverse stress. SHEET REFERENCE

[0018] Figure 1 It is the internal structure schematic drawing of the support mechanism of the utility model one embodiment.

[0019] Figure 2 It is the structure schematic drawing of the support mechanism of the utility model one embodiment.

[0020] Figure 3 It is the structure schematic drawing of the loading pad plate of the utility model one embodiment.

[0021] Figure 4 It is the connection structure schematic drawing of the loading pad plate and the support mechanism of the utility model one embodiment.

[0022] Figure 5 It is the structure diagram of the empty steel pipe axial test device of the utility model one embodiment based on the internal local lateral pressurization of water bag.

[0023] Figure 6 It is the cross section drawing of square steel pipe of the utility model one embodiment.

[0024] Wherein, 1 is a loading pad, 2 is a pressurizing system, 3 is a supporting mechanism, 4 is a square steel pipe, 5 is an upper end plate, 6 is a lower end plate, 7 is a water bag, 8 is a steel plate support plate, 9 is a water bag separation arc plate, 10 is an angle part, 11 is a pressurizing area, 12 is a non-pressurizing area, 13 is a water bag cover plate, 14 is a water inlet pipe, 15 is a water outlet pipe, 16 is a water tank, 17 is a variable frequency water pump, 18 is a control box, 19 is a first pipeline, 20 is a second pipeline, 21 is a valve, 22 is a pressure gauge, 23 is an upper pad, 24 is a lower pad, 25 is a cross stiffening rib, 26 is a slot, 27 is an upper stiffening rib, and 28 is a lower stiffening rib. DETAILED DESCRIPTION

[0025] The utility model will be further explained in connection with the drawings and examples.

[0026] As Figures 1 to 5 shown, the embodiment is based on the water bag and carries out internal local lateral pressurization of the air steel pipe axial test device, including loading pad, pressurizing system and supporting mechanism;The supporting mechanism includes square steel pipe, upper end plate, lower end plate and water bag, and the upper end plate and lower end plate are arranged at the upper end and lower end of square steel pipe respectively, and the loading pad is fixed to the upper end plate;Four inner side walls of the square steel pipe are each provided with a steel plate support plate, and the steel plate support plate is fixed with a water bag separation arc plate on the side away from the inner side wall of the square steel pipe, and the inner side wall of the square steel pipe, the water bag separation arc plate, the upper end plate and the lower end plate form a pressurizing cavity for placing the water bag, the water bag is placed in the pressurizing cavity, and the water bag is connected with the pressurizing system;When the water bag is pressurized, the water bag abuts against the four angle parts of the square steel pipe, and there is a gap between the upper end of the water bag and the upper end plate.

[0027] Specifically, the utility model sets up the water bag separation arc plate in the inner cavity of square steel pipe through the steel plate support plate, so as to separate the inner cavity of square steel pipe into the pressurizing area and the non-pressurizing area of water bag. In order to further ensure the accuracy of test results, the lower end of the water bag separation arc plate is welded and fixed with the lower end plate;At the same time, the water bag cover plate is arranged between the water bag and the upper end plate, so as to avoid the upper end of the water bag from being pressed to the upper end plate after the water bag is pressurized by water injection, so as to ensure that the upper end plate does not press the internal support system formed by the water bag during the axial test.

[0028] The width of the steel plate support plate is less than the width of the inner side wall of the square steel pipe, and the steel plate support plate is tightly arranged in the middle of the corresponding inner side wall of the square steel pipe. This simple arrangement makes the four angle part pressurizing areas separated by the water bag separation arc plate have the same shape, ensures that the water bag uniformly pressurizes the four angle parts of the square steel pipe, and further improves the accuracy of the test.

[0029] The pressurizing system comprises a water inlet pipe, a water outlet pipe, a water tank, a variable frequency water pump and a control box, the water inlet pipe and the water outlet pipe are connected with the water bag, the water inlet pipe and the water outlet pipe are connected with the water tank through a first pipe and a second pipe respectively, valves are arranged on the first pipe and the second pipe, the variable frequency water pump is installed on the first pipe and is located between the water tank and the valve, and the variable frequency water pump is connected with the control box, the first pipe is provided with a pressure gauge, the pressure gauge is located between the valve and the water inlet pipe, and the pressure gauge is connected with the control box, specifically, the water tank, the high-precision variable frequency water pump, the pressure gauge, the water inlet pipe, the water bag, the water outlet pipe and the water tank form a water circulation pressurizing system, meanwhile, the pressure gauge is installed in front of the water inlet pipe, and the variable frequency control box is used for accurately controlling the water pressure in the water bag, so that the accuracy of test results is further improved, the variable frequency water pump is a high-precision variable frequency water pump CDLF2-260, the control box is a variable frequency control box SCKB1-3, the first pipe and the second pipe are both DN25 water pipes, and the pressure gauge is a digital pressure gauge.

[0030] The loading pad plate comprises an upper pad plate, a lower pad plate and intersecting stiffening ribs, the upper pad plate is connected with the lower pad plate through the intersecting stiffening ribs, the lower pad plate is fixed to the upper end plate, and the pad plate is provided with grooves matched with the water inlet pipe and the water outlet pipe.

[0031] The upper end plate and the square steel pipe are fixed with upper stiffening ribs, and the lower end plate and the square steel pipe are fixed with lower stiffening ribs. The upper stiffening ribs and the lower stiffening ribs further ensure the firmness of the square steel pipe to the upper end plate and the lower end plate respectively, and ensure the effective performance of the test.

[0032] After the water pressure setting value is set through the variable frequency control box, the high-precision variable frequency water pump starts to work and transports the water in the water tank to the water bag. The water bag expands and transmits the water pressure to the corner part of the steel pipe column due to the limitation of the water bag separation arc plate and the water bag cover plate, and forms local pressurization to the steel pipe column. In the pressurization process, the digital pressure gauge feeds back the water pressure to the variable frequency control box in real time, and when the water pressure reaches the setting value, the variable frequency control box automatically closes the high-precision variable frequency water pump to prevent excessive pressure.

[0033] It should be noted that for using water bag to simulate the lateral extrusion force of the corner outer steel pipe wall, the water pressure needs to be calculated and determined in advance. As shown in Figure 6 The square steel plate with height y and thickness t in the middle region is investigated, the corner region separated by the arc plate is x, and the water pressure is P. The relationship between the water pressure P and the transverse stress σ of the steel plate in the middle region is as follows:

[0034] F=P·(x·y)

[0035]

[0036] The above specific embodiments are preferred embodiments of the utility model, and cannot limit the utility model. Any change or other equivalent replacement mode without departing from the technical solutions of the utility model is included in the protection scope of the utility model.

Claims

1. An apparatus for internal axial testing of hollow steel pipes based on internal local lateral pressurization with water capsules, characterized in that, The utility model provides a kind of loading cushion plate, pressurizing system and support mechanism;The support mechanism includes square steel pipe, upper end plate, lower end plate and water bag, the upper end plate and lower end plate are respectively arranged in the upper end and lower end of square steel pipe, and the loading cushion plate is fixed to the upper end plate;4 inner side walls of the square steel pipe are each equipped with steel plate support plate, and the steel plate support is fixed with water bag separation arc plate on the side of the inner side wall of square steel pipe, and the inner side wall of square steel pipe, water bag separation arc plate, upper end plate and lower end plate form the pressurizing cavity for placing water bag, the water bag is placed in pressurizing cavity, and water bag is connected with pressurizing system;When water bag is pressurized, water bag is against four edge parts of square steel pipe, and there is gap between the upper end of water bag and upper end plate.

2. The apparatus for internal pressurization of an empty steel pipe by means of internal lateral pressurization of a water bladder according to claim 1, characterized in that, The width of the steel plate support plate is less than the width of the inner side wall of the square steel pipe, and the steel plate support plate is tightly pressed in the middle of the corresponding inner side wall of the square steel pipe.

3. The apparatus for internal pressurization of an empty steel pipe by means of internal lateral pressurization of a water bladder according to claim 1, characterized in that, A water bag cover plate is provided between the water bag and the upper end plate.

4. The apparatus for internal pressurization of an empty steel pipe by means of internal lateral pressurization of a water bladder according to claim 1, characterized in that, The pressurizing system includes a water inlet pipe, a water outlet pipe, a water tank, a variable frequency water pump and a control box, the water inlet pipe and the water outlet pipe are connected with the water bag, and the water inlet pipe and the water outlet pipe are connected with the water tank through a first pipeline and a second pipeline respectively, a valve is provided on the first pipeline and the second pipeline, the variable frequency water pump is installed on the first pipeline, and the variable frequency water pump is located between the water tank and the valve, and the variable frequency water pump is connected with the control box.

5. The apparatus for internal pressurization of an empty steel pipe by means of internal lateral pressurization of a water bladder according to claim 4, characterized in that, The first pipeline is provided with a pressure gauge, and the pressure gauge is located between the valve and the water inlet pipe, and the pressure gauge is connected with the control box.

6. The apparatus for internal pressurization of an empty steel pipe by means of internal lateral pressurization of a water bladder according to claim 4, characterized in that, The loading cushion plate includes an upper cushion plate, a lower cushion plate and a cross stiffening rib, the upper cushion plate is connected with the lower cushion plate through the cross stiffening rib, the lower cushion plate is fixed to the upper end plate, and the cushion plate is provided with a slot matched with the water inlet pipe and the water outlet pipe.

7. The apparatus for internal pressurization of an empty steel pipe by means of internal lateral pressurization of a water bladder according to claim 1, characterized in that, An upper stiffening rib is fixed between the upper end plate and the square steel pipe, and a lower stiffening rib is fixed between the lower end plate and the square steel pipe.

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