Column end restraint system for vertical loading test of polygonal column component

Abstract

The invention discloses a column end restraint system for a vertical loading test of a polygonal column component, and relates to the technical field of civil engineering structure tests. The restraining assembly comprises a plurality of restraining side plates which are sequentially arranged and form a polygonal inner cavity in a surrounding mode, sliding grooves are formed in the restraining side plates in the length direction, hooks are fixedly arranged at one ends of the restraining side plates, and the hook on one restraining side plate penetrates through the sliding groove in the adjacent restraining side plate. An adjusting bolt is arranged on the outer side of each restraining side plate, a connecting portion is arranged at one end of each adjusting bolt, one end of each adjusting bolt is connected with the corresponding hook in a hanging mode through the corresponding connecting portion, and the other end of each adjusting bolt penetrates through the corresponding sliding groove in the adjacent restraining side plate and is in threaded connection with the corresponding nut. The device can be suitable for the test of polygonal column test pieces with different sizes and shapes, can be repeatedly used for multiple times, and effectively prevents the end parts of the column test pieces from being damaged in advance in a vertical loading test.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering structure tests, and particularly to a column end restraint system for vertical loading tests of polygonal column members. Background Art

[0002] With the acceleration of the urbanization process and the development of the construction industry, the shapes of public buildings are becoming more and more complex, and more and more flexible and variable structural forms are widely applied to various buildings. Among them, the design of various irregular column members has become increasingly common. In order to meet the requirements of building shapes, polygonal columns may be used inside buildings. As the main load-bearing members in building structures, it is very necessary to carry out vertical loading tests such as axial compression and eccentric compression on them to obtain mechanical performance indexes such as their bearing capacities. However, during the test process, column members are prone to premature failure at the ends, thus affecting the test results and the determination of relevant data.

[0003] To obtain the true mechanical properties of column members during the test, appropriate reinforcement measures need to be taken at the ends of the column members. Currently, the commonly used reinforcement measures are to set stirrups or welded wire fabric at the ends of the members to improve the local bearing capacity at the column ends, or to use a hoop-type column cap to restrain the cross-section at the column ends, thereby preventing premature failure at the column ends.

[0004] However, the above measures have the following deficiencies: (1) The stirrups and welded wire fabric are cast in a single specimen, which is inconvenient for construction, the restraint device is difficult to reuse, and the expected effect may not necessarily be achieved; (2) Poor geometric compatibility, generally fixed-size hoop-type column caps can only be used for fixed-size cross-sections and cannot be applied to the changes in different cross-section sizes during the test; (3) For column members that need to be cast with concrete, due to the inevitable dimensional deviation problems during their formwork support and casting processes, it is difficult for fixed-size hoop-type column caps to fit the actual member sizes. Summary of the Invention

[0005] The purpose of the present invention is to provide a column end restraint system for vertical loading tests of polygonal column members to solve the problems existing in the above-mentioned prior art, which can be applicable to tests of polygonal column specimens with different sizes and shapes, can be reused multiple times, and effectively avoid premature failure at the ends of column specimens during vertical loading tests.

[0006] To achieve the above purpose, the present invention provides the following solution:

[0007] The present invention provides a column end restraint system for vertical loading tests of polygonal column members, including two restraint components;

[0008] The constraint component includes a plurality of constraint side plates that are sequentially arranged and surround to form a polygonal inner cavity. A chute is provided on the constraint side plate along the length direction. A hook is fixedly provided at one end of the constraint side plate. The hook on one constraint side plate passes through the chute on the adjacent constraint side plate.

[0009] An adjusting bolt is provided on the outside of each constraint side plate. One end of the adjusting bolt has a connecting portion. One end of the adjusting bolt is hooked to the hook through the connecting portion, and the other end passes through the chute on the adjacent constraint side plate and is threadedly connected to a nut.

[0010] In one embodiment, the constraint side plate is a steel plate.

[0011] In one embodiment, the hook is welded and fixed to the constraint side plate.

[0012] In one embodiment, a wedge-shaped gasket is sleeved on the adjusting bolt for use in combination with the nut.

[0013] In one embodiment, the adjusting bolt includes a shepherd's hook bolt or a lifting eye bolt.

[0014] In one embodiment, the dimensions of the constraint side plate satisfy:

[0015] b s +200≥l b ≥b s +100,

[0016] h b =1 / 6h s ,

[0017]

[0018] In the formula, l b is the length of the constraint side plate (mm); h b is the height of the constraint side plate (mm); t b is the thickness of the constraint side plate (mm); b s is the side length of the test specimen to be tested (mm); h s is the height of the test specimen to be tested (mm); f ys is the yield strength of the constraint side plate (N / mm 2 ); k e is the effective constraint effect coefficient, which is taken as 1 / 3 for a rectangular plate; k1 is the lateral constraint coefficient of the constraint side plate on the concrete;

[0019] Among them,

[0020] In the formula, k2 is the lateral constraint coefficient of each component of the test specimen to be tested on the concrete, fm is the lateral binding force of each component of the specimen to be tested on the concrete.

[0021] In one embodiment, the size of the chute satisfies:

[0022] b c = d l + 2,

[0023] l c = 0.8l b ,

[0024] wherein, b c is the width of the chute (mm); l c is the length of the chute (mm); d l is the diameter of the adjusting bolt (mm).

[0025] In one embodiment, the size of the adjusting bolt satisfies:

[0026]

[0027] l l = 1.2b s ,

[0028] wherein, f yl is the tensile strength of the adjusting bolt (N / mm 2 ), l l is the length of the adjusting bolt (mm).

[0029] The present invention has achieved the following technical effects compared with the prior art:

[0030] (1) Compared with the measures such as densifying stirrups and setting steel mesh at the column end, the present invention has the advantages of simple construction, low cost, and easy guarantee of concrete pouring quality;

[0031] (2) The present invention can be applied to polygonal columns with different sizes and shapes;

[0032] (3) By means of the adjusting bolt (high-strength bolt), the present invention fixes the constraint side plate circumferentially along the end of the specimen, which is simple and practical, without relatively complex and high-precision installation processes such as welding, and will not weaken the cross-section of the specimen during the test;

[0033] (4) The device of the present invention is convenient to disassemble, can be reused, and can be applied to polygonal column members with different cross-sectional sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 It is a schematic structural diagram when the column end constraint system for the vertical loading test of the polygonal column member in the embodiment of the present invention is in use;

[0036] Figure 2 It is a top view of the column end constraint system for the vertical loading test of the polygonal column member in the embodiment of the present invention;

[0037] Figure 3 It is a schematic structural diagram of the constraint side plate in the embodiment of the present invention.

[0038] In the figure: 100 - constraint assembly, 1 - constraint side plate, 2 - chute, 3 - hook, 4 - adjustment bolt, 5 - connection part, 6 - nut, 7 - wedge gasket, 8 - column specimen. Detailed implementation manners

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0040] The purpose of the present invention is to provide a column end constraint system for the vertical loading test of polygonal column members, to solve the problems existing in the prior art, which can be applicable to the tests of polygonal column specimens with different sizes and shapes, can be reused multiple times, and effectively avoid the premature failure of the ends of column specimens during the vertical loading test.

[0041] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the drawings and specific implementation manners.

[0042] As Figures 1 - 3 shown, this embodiment provides a column end constraint system for the vertical loading test of polygonal column members, including two constraint assemblies 100;

[0043] The constraint assembly 100 includes a plurality of constraint side plates 1 arranged in sequence and surrounding to form a polygonal inner cavity. A chute 2 is provided on the constraint side plate 1 along the length direction. A hook 3 is fixedly provided at one end of the constraint side plate 1. The hook 3 on one constraint side plate 1 passes through the chute 2 on the adjacent constraint side plate 1;

[0044] On the outside of each constraint side plate 1, an adjusting bolt 4 is provided. One end of the adjusting bolt 4 has a connecting portion 5. One end of the adjusting bolt 4 is hooked to the hook 3 through the connecting portion 5, and the other end passes through the sliding groove 2 on the adjacent constraint side plate 1 and is threadedly connected to the nut 6.

[0045] When performing vertical loading tests with multiple sets of variable cross-sectional shapes and sizes, by adjusting the number of constraint side plates 1 and adjusting bolts 4, it can be applied to column specimens 8 with different cross-sectional shapes. By adjusting the relative positions of the high-strength adjusting bolts 4 and the hooks 3 in the sliding groove 2, it can adapt to column specimens 8 with different sizes. Therefore, this device has good geometric compatibility and error tolerance. In addition, this device uses a fully bolted assembly connection, which is fast and convenient and does not require professional welding operations. It can be disassembled and reused multiple times, having certain economic benefits.

[0046] During use, according to the number of sides of the column specimen 8, each constraint assembly 100 is set to the corresponding number of constraint side plates 1. The two constraint assemblies 100 are respectively sleeved on both ends of the column specimen 8. By tightening the nut 6, the constraint assembly 100 can be tightly fastened to the surface of the column specimen 8. Each constraint side plate 1 closely adheres to the side of the column specimen 8, and the forces on each adjusting bolt 4 are balanced.

[0047] Specifically, in this embodiment, the column specimen 8 is a pentagonal column, and five constraint side plates 1 are provided in each corresponding constraint assembly 100. The two constraint assemblies 100 are respectively tightly fastened to the upper and lower ends of the pentagonal column.

[0048] In this embodiment, the constraint side plate 1 is a steel plate. The hook 3 is welded (groove welding) and fixed to the constraint side plate 1.

[0049] In this embodiment, a wedge-shaped gasket 7 is sleeved on the adjusting bolt 4. The wedge-shaped gasket 7 is arranged between the nut 6 and the constraint side plate 1 and is used in combination with the nut 6 to improve the connection tightness to prevent slipping.

[0050] Among them, the adjusting bolt 4 is a high-strength bolt with a hook or a ring at one end, such as a high-strength eye bolt or a high-strength lifting ring bolt, etc. It is hooked to the hook 3 through the hook or the ring at its end. The connecting portion 5 is the hook or the ring structure at its end.

[0051] Among them, the size of the constraint side plate 1 satisfies:

[0052] b s +200≥l b ≥b s +100,

[0053] h b =1 / 6h s ,

[0054]

[0055] wherein, l b is the length of the restraint side plate (mm); h b is the height of the restraint side plate (mm); t b is the thickness of the restraint side plate (mm); b s is the side length of the specimen to be tested (mm); h s is the height of the specimen to be tested (mm); f ys is the yield strength of the restraint side plate (N / mm 2 ); k e is the effective restraint effect coefficient, which is taken as 1 / 3 for a rectangular plate; k1 is the lateral restraint coefficient of the restraint side plate on the concrete;

[0056] Among them,

[0057] wherein, k2 is the lateral restraint coefficient of each component of the specimen to be tested on the concrete, and f m is the lateral restraint force of each component of the specimen to be tested on the concrete.

[0058] The dimensions of the sliding groove 2 satisfy:

[0059] b c = d l + 2,

[0060] l c = 0.8l b ,

[0061] wherein, b c is the width of the sliding groove (mm); l c is the length of the sliding groove (mm); d l is the diameter of the adjusting bolt (mm).

[0062] The dimensions of the adjusting bolt 4 satisfy:

[0063]

[0064] l l = 1.2b s ,

[0065] wherein, f yl is the tensile strength of the adjusting bolt (N / mm 2 ), and l l is the length of the adjusting bolt (mm).

[0066] Calculate the dimensions of the restraint side plate 1, the sliding groove 2 and the adjusting bolt 4 through the above formulas to ensure that the prepared column end restraint system can meet the strength requirements and will not collapse during use.

[0067] The column end restraint system provided by the present invention can make the bearing capacity of the end of the column specimen 1.5 times that of the middle part, so as to ensure that premature failure at the end will not occur.

[0068] The column end restraint system provided by the present invention can avoid the phenomenon of premature failure at the end of the column specimen without affecting the overall performance of the column specimen, thereby affecting the results of mechanical tests and the determination of relevant test data.

[0069] The present invention is applicable to the tests of polygonal column specimens with different sizes and shapes, can be reused multiple times, and effectively avoids premature failure of the ends of column specimens during vertical loading tests.

[0070] Specific examples are used in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A column end restraint system for vertical loading test of polygonal column members, characterized by: It includes two constraint components; The restraint assembly comprises a plurality of restraint side plates arranged in sequence and surrounding a polygonal inner cavity, wherein a slide groove is provided on the restraint side plate along the length direction, a hook is fixedly provided at one end of the restraint side plate, and the hook on one restraint side plate passes through the slide groove on the adjacent restraint side plate; An adjusting bolt is provided on the outer side of each of the restraining side plates, one end of the adjusting bolt has a connecting portion, one end of the adjusting bolt is hooked to the hook through the connecting portion, and the other end passes through the sliding groove on the adjacent restraining side plate and is threadedly connected to the nut.

2. The column end restraint system for vertical loading test of polygonal column members according to claim 1 is characterized in that: The restraining side plate is a steel plate.

3. The column end restraint system for vertical loading test of polygonal column members according to claim 1, characterized in that: The hook is welded and fixed on the restraining side plate.

4. The column end restraint system for vertical loading test of polygonal column members according to claim 1, characterized in that: The adjusting bolt is sleeved with a wedge-shaped washer for use with the nut.

5. The column end restraint system for vertical loading test of polygonal column members according to claim 1, characterized in that: The adjusting bolt comprises an eye bolt or an eye bolt.

6. The column end restraint system for vertical loading test of polygonal column members according to claim 1, characterized in that: The dimensions of the restraining side panels satisfy: b s +200≥l b ≥b s +100, h b =1 / 6h s , In the formula, l b h is the length of the restrained side panel (mm); b is the height of the restrained side panel (mm); t b b is the thickness of the constraint side plate (mm); s h is the side length of the test piece (mm); s is the height of the test piece (mm); f ys is the yield strength of the restrained side plate (N / mm 2 );k e is the effective constraint effect coefficient, which is taken as 1 / 3 for rectangular slabs; k1 is the lateral constraint coefficient of the restrained side slab on the concrete; in, Where k2 is the lateral constraint coefficient of each component of the test piece on the concrete, f m It is the lateral restraint force of each component of the test piece on the concrete.

7. The column end restraint system for vertical loading test of polygonal column members according to claim 6, characterized in that: The dimensions of the chute satisfy: b c =d l +2, l c ＝0.8l b ， Where b c is the width of the slideway (mm); l c is the length of the slideway (mm); d l is the diameter of the adjusting bolt (mm).

8. The column end restraint system for vertical loading test of polygonal column members according to claim 7, characterized in that: The dimensions of the adjusting bolt meet the following requirements: l l ＝1.2b s ， In the formula, f yl To adjust the tensile strength of the bolt (N / mm 2 ), l l is the length of the adjusting bolt (mm).

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