CN212513996U - Concrete uniaxial tension load holding test device - Google Patents
Concrete uniaxial tension load holding test device Download PDFInfo
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- CN212513996U CN212513996U CN202021204781.3U CN202021204781U CN212513996U CN 212513996 U CN212513996 U CN 212513996U CN 202021204781 U CN202021204781 U CN 202021204781U CN 212513996 U CN212513996 U CN 212513996U
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Abstract
The load test device is held in concrete unipolar tensioning, the utility model discloses a rotatory four finish rolling nuts that are close to upper portion ball pivot one side simultaneously realize applying axial tension to the concrete test block. And the connecting sleeve adhered with the strain gauge is also used as a load sensor to obtain a load, and the fine adjustment of the load is realized by slightly rotating the second specification of the finish rolling nut. The utility model discloses need not adopt solitary load sensor, establish the method that the resistance strain gauge was pasted to the connecting sleeve of screw thread, outer light circle in the adoption makes it be load sensor concurrently, has simplified test device, has reduced and has held the cost problem that the lotus needs to occupy a large amount of load sensors for a long time. The sleeve load holding device is simple to operate and can provide stable and effective continuous load.
Description
Technical Field
The utility model belongs to the civil engineering field, concretely relates to concrete unipolar is drawn and is held lotus test device.
Background
It is well known that concrete is one of the most widely used building materials in current engineering construction, compressive strength being its most significant feature, and tensile strength being of less concern. Therefore, in modern structures, concrete is mainly used for bearing compressive strength, and the tensile strength of concrete is generally only 1/17-1/8 of the compressive strength, so that the tensile strength of concrete can be achieved with a small load, and the tensile strength of concrete is usually ignored in the structure design and is borne by steel bars. In some structures, such as fully prestressed concrete structures, tensile stresses are not allowed, while in partially prestressed structures tensile stresses are allowed.
The tensile strength and deformation of concrete are among the most important basic properties of concrete. It is an important component for researching concrete strength theory and failure mechanism, and also an important factor for influencing the cracking, deformation and durability of concrete structure. In addition, the tensile strength is also a main factor influencing the shear resistance of the concrete and is an important parameter for establishing a multiaxial failure criterion of the concrete. In recent years, along with the construction of a large number of high-rise buildings and large-span bridge projects, the proportion of high-performance concrete used in modern structures is higher and higher, and the high-performance concrete has the main characteristic of high durability, and a plurality of macroscopic cracks appear on the surfaces of actual structures such as bridges, crane beams, pavements, ocean platforms and the like, so that the durability, the safety and the reliability of the structures and the service life of the structures are seriously influenced. The development of concrete cracks is mainly related to tensile strength, so that the research on the tensile property of concrete is of great significance.
The test research on the concrete tensile strength of the concrete is only in the initial stage for a long time, and in addition, the great discreteness of the concrete is realized, and the backward of the concrete tensile test equipment, the understanding of the tensile strength of people is lack of integrity. After the 60 s of the 20 th century, researchers developed a series of concrete tensile test devices, which can measure the whole curve of the tensile stress and strain of concrete, but the test devices adopted by the researchers are different. In the previous research, the research on the long-term performance of a concrete uniaxial tension test piece under continuous load, particularly the durability under an erosion service environment (coupling action of load and erosion environment) is less, and in the test process, the concrete axial tension is realized by a physical centering method, so that the operation is complex, and the centering condition is difficult to control. Therefore, no known effective method exists at present, if the test piece cannot be centered, the test piece will be broken quickly once loaded, the test will fail, and the requirement of the durability test on the environmental conditions such as test temperature, humidity and the like is very strict; in addition, the operation process of the test is very complex, and the requirements on test equipment, a data acquisition system, the performance of a test piece and test conditions are very high. Therefore, a set of concrete uniaxial tension holding load test device needs to be established as early as possible.
SUMMERY OF THE UTILITY MODEL
The utility model discloses to using traditional concrete to be drawn test device, concrete test piece centering difficulty, the comparatively complicated problem of experimental operation process provide a concrete unipolar and drawn and hold lotus test device, the utility model discloses a method that both ends add the ball pivot to guarantee that the concrete axle center is drawn.
The technical scheme of the utility model as follows:
the concrete uniaxial tension load test device is characterized by comprising a concrete test block, a top steel plate, a bottom steel plate, four second pre-stressed finish-rolled twisted steel bars, two spherical hinges, a common connecting rod, a lengthened connecting rod and two square anchor plates; the top steel plate and the bottom steel plate respectively penetrate through the four second pre-stress finish rolling threaded steel bars and are respectively arranged on the upper part and the lower part of the second pre-stress finish rolling threaded steel bars in parallel; the top steel plate and the bottom steel plate are in rotating contact with the spherical hinge, the lengthened connecting rod is fixedly connected with the spherical hinge at the top into a whole, and the common connecting rod is fixedly connected with the spherical hinge at the bottom into a whole;
the two square anchor plates are fixedly connected with the top end and the bottom end of the concrete test block through four corners of the two square anchor plates respectively, and first pre-stressed finish-rolled twisted steel bars are fixed in the middle of the two square anchor plates respectively; the end parts of the two first pre-stress finish rolling twisted steel bars are respectively in threaded screwed connection with connecting sleeves, and the two connecting sleeves are respectively in threaded screwed connection with the common connecting rod and the lengthened connecting rod;
four finish rolling nuts are arranged at the bottom of the top steel plate and are screwed with corresponding second pre-stressed finish rolling threaded steel bars, and steel washers are arranged between the finish rolling nuts and the top steel plate; the four finish rolling nuts at the bottom of the top steel plate are rotated simultaneously to apply axial tension to the concrete test block.
Furthermore, four finish rolling threaded steel bars are respectively prefabricated at the top end and the bottom end of the concrete test block and are exposed for a certain length; and the four corners of the square anchor plate are respectively provided with a preformed hole, four finish-rolled twisted steel bars pass through the four preformed holes of the corresponding square anchor plate, the finish-rolled twisted steel bars are screwed into the finish-rolled nuts, and the two square anchor plates and the concrete test block are connected into a whole.
Furthermore, the bottom steel plate and the top steel plate are variable cross-section steel plates.
Furthermore, four finish rolling nuts are arranged on the bottom steel plate and are in screwed connection with corresponding second pre-stressed finish rolling threaded steel bars, and steel washers are arranged between the finish rolling nuts and the bottom steel plate.
Furthermore, the top steel plate and the bottom steel plate are respectively fixed with a reinforced circular steel tube, and the two reinforced circular steel tubes are respectively sleeved on the lengthened connecting rod and the common connecting rod.
Further, four rectangular stiffening rib steel plates are uniformly arranged in the circumferential direction of the two reinforced circular steel tubes and fixedly connected with the corresponding steel plates, and the reinforced circular steel tubes and the corresponding steel plates are connected in four directions to ensure that the spherical hinges are not locally damaged.
Furthermore, the outer surface of the upper connecting sleeve is pasted with a strain gauge which is also used as a load sensor, and the strain gauge is connected with a resistance strain gauge through a connecting lead.
When the device is used, the four finish rolling nuts at the bottom of the top steel plate are simultaneously rotated to apply an outward force to the top steel plate, so that the lengthened connecting rod, the connecting sleeve and the first pre-stressed finish rolling twisted steel are sequentially driven to be stressed, and a concrete test block is pulled; meanwhile, the bottom steel plate limits the movement of the first pre-stressed finish-rolled twisted steel bar and the square anchor plate, so that the load holding of the concrete test block is realized; the magnitude of the continuous load is obtained by using a connecting sleeve pasted with a strain gauge as a load sensor, and fine adjustment of the load is realized by slightly rotating a finish rolling nut at the bottom of a top steel plate; in the load holding process, the upper variable cross-section steel plate surface and the lower variable cross-section steel plate surface are ensured to be parallel.
The utility model discloses need not adopt solitary load sensor, establish the method that the resistance strain gauge was pasted to the connecting sleeve of screw thread, outer light circle in the adoption makes it be load sensor concurrently, has simplified test device, has reduced and has held the cost problem that the lotus needs to occupy a large amount of load sensors for a long time. The sleeve load holding device is simple to operate and can provide stable and effective continuous load.
The steel plate of the utility model is made of stainless steel; the utility model discloses a rotatory four finish rolling nuts that are close to upper portion ball pivot one side simultaneously realize applying axial tension to the concrete test block. And the connecting sleeve adhered with the strain gauge is also used as a load sensor to obtain a load, and the fine adjustment of the load is realized by slightly rotating the second specification of the finish rolling nut.
The beneficial effects of the utility model reside in that:
1. the utility model provides a concrete single-shaft tensile load-holding test device which has simple structure and easy operation;
2. the load holding device can provide reliable and stable load for the concrete test block by screwing the second specification of the finish rolling nut, can meet the requirement of long-term loading, and the spherical hinge at the end part can rotate when meeting eccentric force, so that the steel plate can be stably pushed, and axial tension can be applied to the concrete test block, thereby avoiding adverse effect on the test caused by eccentric tension;
3. the load holding device can apply continuous load to the test piece without using a reaction frame, and the connecting sleeve adhered with the strain gauge is also used as a load sensor, so that the space occupied by the loading device is greatly reduced;
4. the load holding device is made of corrosion-resistant stainless steel materials and is not easy to rust. After the test piece is kept loaded, the test piece is placed into an erosion environment simulation device (such as a freeze-thaw test box, a carbonization box, a chloride salt and sulfate erosion solution environment and the like) so that the test piece is in a state of coupling action of load and an erosion environment, and the service stress state of the erosion environment is simulated.
Drawings
FIG. 1 is a schematic view of a concrete uniaxial tension holding load test device;
FIG. 2 is a schematic view of a square anchor plate;
FIG. 3 is a cross-sectional view taken along line A-A of FIG. 1;
FIG. 4 is a schematic view of a steel washer;
in the figure, 1 is the concrete test block, 2 is finish rolling twisted steel, 3 is square anchor slab, 4 is prestressing force finish rolling twisted steel specification one (first prestressing force finish rolling twisted steel), 5 is finish rolling nut specification one, 6 is the connecting sleeve, 7 is ordinary connecting rod, 8 is the extension connecting rod, 9 is the reinforcing circular steel tube, 10 is the rectangle stiffening rib steel sheet, 11 is the ball pivot, 12 is prestressing force finish rolling twisted steel specification two (second prestressing force finish rolling twisted steel), 13 steel packing ring, 14 is finish rolling nut specification two, 15 is the foil gage, 16 is the resistance strain gauge, 17 is connecting wire.
Detailed Description
The present invention will be further explained with reference to the accompanying drawings.
As shown in figure 1, the concrete uniaxial tension holding load test device comprises a concrete test block 1, finish rolling threaded steel bars 2, a square anchor plate 3, a prestressed finish rolling threaded steel bar specification I4, a finish rolling nut specification I5, a connecting sleeve 6, a common connecting rod 7, an extension connecting rod 8, a reinforced circular steel tube 9, a rectangular stiffening rib steel plate 10, a spherical hinge 11, a prestressed finish rolling threaded steel bar specification II 12, a steel gasket 13, a finish rolling nut specification II 14, a strain gauge 15, a resistance strain gauge 16 and a connecting wire 17. The concrete test block 1 (120 mm multiplied by 400 mm) is a non-standard type, the influence of reducing the end stress effect is considered, the tensile damage is ensured to occur in the middle part, the area of the middle part of the test piece is reduced, the test piece is poured and formed by adopting a self-made steel die, the die is removed after 24 hours, and the test piece is placed into a standard curing chamber for curing after the die is removed; eight finish-rolled twisted steel bars 2 (with the length of 150 mm) are respectively embedded at two ends of the concrete test block so as to realize the uniform distribution of axial tensile strength and stress, provide enough anchoring strength and expose the finished twisted steel bars for a certain length, thereby facilitating the test operation; the device is divided into an upper part and a lower part by a concrete test block 1 and finish-rolled twisted steel bars 2 pre-embedded in the concrete test block.
For the upper half part of the device, as shown in fig. 2, the square anchor plate 3 is arranged at the end part of the concrete test block 1, four reserved holes are arranged at four corners, and the center of the square anchor plate is welded with a prestressed finish-rolled twisted steel specification I4 to form a whole; the first precision rolling nut specification 5 is provided with four corners of a square anchor plate 3 and is used for connecting a precision rolling threaded steel bar 2 with the square anchor plate 3, and further connecting a concrete test block 1 with a first prestress precision rolling threaded steel bar specification 4; the connecting sleeve 6 is provided with an internal thread and has a smooth outer surface, and the prestress finish rolling twisted steel specification I4 and the lengthened connecting rod 8 are connected together through the connecting sleeve 6; the reinforced circular steel tube 9 is fixed with the variable cross-section steel plate at the end part of the spherical hinge 11, and is sleeved on the lengthened connecting rod 8, and a certain distance is reserved between the reinforced circular steel tube and the lengthened connecting rod 8.
As shown in fig. 3, the rectangular stiffening rib steel plate 10 is used for connecting the reinforced circular steel tube 9 and the spherical hinge 11 in four directions so as to prevent the spherical hinge from being locally damaged; the spherical hinge 11 can rotate under the action of eccentric force; the variable cross-section steel plate is a part of the spherical hinge, four reserved holes are arranged at four corners, and the variable cross-section steel plate is designed to be heavy due to the fact that the thickness of the steel plate is large.
For the lower half of the device, the elongated connecting rods 8 in the upper half are replaced by ordinary connecting rods 7, and the rest of the device is the same as the upper half of the device.
And the second 12 specification of the prestressed finish-rolled twisted steel is four, and the four specifications respectively penetrate reserved holes at four corners of the upper and lower variable cross-section steel plates.
As shown in fig. 4, the steel washer 13 is circular and is arranged between the variable cross-section steel plate and the second finish rolling nut specification 14, the inner diameter of the steel washer is slightly larger than the diameter of the second prestressed finish rolling twisted steel specification 12, and the outer diameter of the steel washer is larger than the diameter of the circumscribed circle of the second finish rolling nut specification 14; and the second finish rolling nut specification 14 connects the second prestressed finish rolling twisted steel specification 12 with the upper and lower variable cross-section steel plates.
Further, the diameter of the preformed hole on the square anchor plate 3 is larger than that of the finish-rolled twisted steel bar 2.
The diameter of the first prestress finish rolling threaded steel bar specification 4 is larger than the diameter of the second prestress finish rolling threaded steel bar specification 12.
And the first precision rolling nut specification 5 and the second precision rolling nut specification 14 are both hexagon nuts.
The lengthened connecting rod 8 and the common connecting rod 7 are both made of steel and are respectively integrated with the spherical hinges 11 at the upper end and the lower end.
A certain distance is left between the reinforced circular steel tube 9 and the connecting sleeve 6.
The preformed hole on the variable cross-section steel plate at the end part of the spherical hinge 11 is a circular through hole, the diameter of the preformed hole is larger than that of the second prestressed finish-rolled twisted steel specification 12, and the groove is reserved in the middle of the variable cross-section steel plate to be in rotary contact with the spherical hinge.
Still further, the surface of the connecting sleeve 6 of the upper half part of the device is pasted with a strain gauge 15 which is also used as a load sensor. The strain gauge 15 is connected with a resistance strain gauge 16 through a connecting lead 17, the connecting sleeve 6 is pulled when the load is held, the tensile strain can be displayed by the resistance strain gauge 16 and converted into the tensile force applied to the connecting sleeve 6 through calculation, and the tensile force applied to the connecting sleeve 6 is the continuous load applied to the concrete test block 1.
The device is made of corrosion-resistant stainless steel materials, and the durability of the device is not reduced under the action of an erosion environment.
The utility model provides a concrete unipolar is drawn and is held lotus test device, the continuous load in normal use state, realize through two 14 of four finish rolling nut specifications of rotatory upper end variable cross section steel sheet inboard simultaneously, exert outside power to the variable cross section steel sheet through two 14 of rotatory finish rolling nut specification, drive extension connecting rod 8 in proper order, connecting sleeve 6, prestressing finish rolling twisted steel specification 4 atress, and then make concrete test block 1 draw, the removal of prestressing finish rolling twisted steel specification 4 and square anchor slab 3 has been restricted to lower extreme variable cross section steel sheet simultaneously, and then realize holding lotus of concrete test block 1. The magnitude of the continuous load is obtained by using the connecting sleeve 6 adhered with the strain gauge as a load sensor, and the second specification 14 of the finish rolling nut is slightly rotated to realize fine adjustment of the load. In the load holding process, the upper variable cross-section steel plate surface and the lower variable cross-section steel plate surface are ensured to be parallel. Then, the test piece is placed into an erosion environment simulation device after being loaded, and is placed for a period of time.
Finally, the present invention is not limited to the above embodiments, and many variations can be made on the basis of the essential contents of the present invention, and all variations that can be directly suggested by a person skilled in the art on the basis of the contents of the present invention should be considered as the protection scope of the present invention.
Claims (7)
1. The concrete uniaxial tension load test device is characterized by comprising a concrete test block, a top steel plate, a bottom steel plate, four second pre-stressed finish-rolled twisted steel bars, two spherical hinges, a common connecting rod, a lengthened connecting rod and two square anchor plates; the top steel plate and the bottom steel plate respectively penetrate through the four second pre-stress finish rolling threaded steel bars and are respectively arranged on the upper part and the lower part of the second pre-stress finish rolling threaded steel bars in parallel; the top steel plate and the bottom steel plate are in rotating contact with the spherical hinge, the lengthened connecting rod is fixedly connected with the spherical hinge at the top into a whole, and the common connecting rod is fixedly connected with the spherical hinge at the bottom into a whole;
the two square anchor plates are fixedly connected with the top end and the bottom end of the concrete test block through four corners of the two square anchor plates respectively, and first pre-stressed finish-rolled twisted steel bars are fixed in the middle of the two square anchor plates respectively; the end parts of the two first pre-stress finish rolling twisted steel bars are respectively in threaded screwed connection with connecting sleeves, and the two connecting sleeves are respectively in threaded screwed connection with the common connecting rod and the lengthened connecting rod;
four finish rolling nuts are arranged at the bottom of the top steel plate and are screwed with corresponding second pre-stressed finish rolling threaded steel bars, and steel washers are arranged between the finish rolling nuts and the top steel plate; the four finish rolling nuts at the bottom of the top steel plate are rotated simultaneously to apply axial tension to the concrete test block.
2. The concrete uniaxial tension and load test device of claim 1, wherein four finish rolling twisted steel bars are prefabricated at the top end and the bottom end of the concrete test block respectively and are exposed for a certain length; and the four corners of the square anchor plate are respectively provided with a preformed hole, four finish-rolled twisted steel bars pass through the four preformed holes of the corresponding square anchor plate, the finish-rolled twisted steel bars are screwed into the finish-rolled nuts, and the two square anchor plates and the concrete test block are connected into a whole.
3. The concrete uniaxial tension and load test device of claim 1, wherein the bottom steel plate and the top steel plate are variable cross-section steel plates.
4. The concrete uniaxial tension holding load test device of claim 2, wherein four finish rolling nuts are provided on the bottom steel plate to be screwed with the corresponding second pre-stressed finish rolling twisted steel, and a steel washer is provided between the finish rolling nuts and the bottom steel plate.
5. The concrete uniaxial tension load test device of claim 4, wherein the top steel plate and the bottom steel plate are respectively fixed with a reinforced circular steel tube, and the two reinforced circular steel tubes are respectively sleeved on the lengthened connecting rod and the common connecting rod.
6. The concrete uniaxial tension load test device of claim 5, wherein four rectangular stiffening rib steel plates are uniformly arranged in the circumferential direction of the two round reinforcing steel pipes, and the four rectangular stiffening rib steel plates are fixedly connected with the corresponding steel plates and used for connecting the round reinforcing steel pipes and the corresponding steel plates in four directions so as to ensure that the ball joints are not locally damaged.
7. The concrete uniaxial tension load test device as claimed in claim 6, wherein a strain gauge is adhered to the outer surface of the upper connecting sleeve and also used as a load sensor, and the strain gauge is connected with a resistance strain gauge through a connecting lead.
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| CN202021204781.3U CN212513996U (en) | 2020-06-24 | 2020-06-24 | Concrete uniaxial tension load holding test device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111707541A (en) * | 2020-06-24 | 2020-09-25 | 扬州大学 | Concrete uniaxial tension holding load and testing device and using method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111707541A (en) * | 2020-06-24 | 2020-09-25 | 扬州大学 | Concrete uniaxial tension holding load and testing device and using method thereof |
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