Prefabricated external ECC jacket combination column

Abstract

The invention relates to the technical field of constructional engineering, in particular to a prefabricated external ECC jacket combination column which comprises a column body and a prefabricated ECC jacket mechanism, and the prefabricated ECC jacket mechanism is located in a plastic hinge area of the column body; the prefabricated ECC clamping sleeve mechanism comprises a plurality of clamping sleeve single pieces and a plurality of connecting assemblies, the multiple clamping sleeve single pieces are fixedly arranged on the periphery of the column body in a sleeving mode at intervals, and the connecting assemblies are connected between every two adjacent clamping sleeve single pieces; the connecting assembly comprises a connecting frame body, a damping piece and a detecting piece, the damping piece and the detecting piece are installed in the connecting frame body, and the clamping sleeve single piece is inserted and fixed into the connecting frame body from the two ends. Through the synergistic effect of the prefabricated ECC jackets and the connecting assemblies, the stress-strain level of concrete in the column body is remarkably improved, then the anti-seismic property is greatly enhanced, the problem that through cracks are likely to occur in a traditional reinforcing mode is fundamentally solved, and it is ensured that the jacket structure continuously plays a constraint effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building engineering, and in particular to a prefabricated external ECC jacketed composite column. BACKGROUND

[0002] In building frame structures, columns as key load transfer components bear the important function of connecting upper and lower parts, and their performance is directly related to the safety and use efficiency of the overall structure. In order to improve the seismic toughness of column components, the application of ultra-high performance engineering cement-based composite material (ECC) has been widely studied in the engineering field, and jacket reinforcement technology is one of the main forms.

[0003] However, the existing ECC jacket reinforcement scheme usually only wraps ECC material as an outer layer on the outside of the ordinary concrete column, which has obvious limitations: first, under the action of load, vertical through cracks or local buckling failure may occur too early, resulting in premature failure of the reinforced layer; second, the reinforcement method solely relying on the performance of ECC material has limited improvement on the seismic performance of the column, and the ECC material has strict requirements on maintenance conditions and molding process, which is not conducive to large-scale engineering promotion. These problems seriously restrict the practical application of ECC jacket technology. SUMMARY

[0004] The present application aims to provide a prefabricated external ECC jacketed composite column to solve the technical problems of existing structural columns with ECC jackets that are prone to premature vertical through cracks or local buckling failure under load and have limited seismic performance improvement. The specific technical solution is as follows: The present application provides a prefabricated external ECC jacketed composite column, which includes a column body and a prefabricated ECC jacket mechanism. The prefabricated ECC jacket mechanism is located in the plastic hinge area of the column body. The prefabricated ECC jacket mechanism includes multiple jacket units and multiple connection components. The multiple jacket units are fixed to the outer periphery of the column body in a spaced jacketed manner, and the connection components are connected between adjacent two jacket units. The connection component includes a connection frame, a damping piece, and a detection piece. The damping piece and the detection piece are installed inside the connection frame, and the jacket unit is inserted and fixed into the connection frame from both ends.

[0005] Further improvement of the prefabricated external ECC jacketed composite column of the present application is that the cross section of the connection frame is H-shaped, and the middle part of the connection frame forms a receiving chamber. The damping piece and the detection piece are installed in the receiving chamber.

[0006] Further improvement of the prefabricated external ECC jacketed composite column of the present application is that the connection frame includes an inner side ring-shaped plate, an outer side L-shaped plate, and an outer side T-shaped plate. The inner side ring-shaped plate is fixed to the outer periphery of the column body in a jacketed manner. The outer L-shaped plate is fixed on the inner annular plate, and a first space for inserting and mounting the jacket single piece is formed between the outer L-shaped plate and the lower part of the inner annular plate; The outer T-shaped plate is fixed on the inner annular plate, and a second space for inserting and mounting the jacket single piece is formed between the outer T-shaped plate and the upper part of the inner annular plate, and the accommodation cavity is formed between the outer T-shaped plate and the middle part of the inner annular plate.

[0007] The further improvement of the prefabricated external ECC jacket combined column of the application is that a ring-shaped U-shaped plate is fixed outside the turning part of the outer L-shaped plate, the lower flange plate of the outer T-shaped plate is inserted into the ring-shaped U-shaped plate, and the end of the lower flange plate of the outer T-shaped plate has a gap with the bottom wall of the ring-shaped U-shaped plate.

[0008] The further improvement of the prefabricated external ECC jacket combined column of the application is that the damping member is a spring, and the stiffness coefficient of the spring is calculated by the following formula: ; ; wherein, is the predominant frequency of the earthquake, is the characteristic period of the earthquake; is the mass of the upper jacket single piece and the outer T-shaped plate of the damping spring, and the pre-pressing amount of the spring under different seismic fortification intensities β is calculated by the following formula: ; wherein, is the acceleration of gravity.

[0009] The further improvement of the prefabricated external ECC jacket combined column of the application is that the number of the jacket single pieces is three, the three jacket single pieces are arranged at intervals along the length direction of the column body, the height of the bottom jacket single piece : ; wherein, is the height of the column, is the tensile strength of the longitudinal reinforcement, is the diameter of the longitudinal reinforcement; the height of the middle jacket single piece and the height of the top jacket single piece are respectively: ; ; wherein, is the width of the column section.

[0010] The further improvement of the prefabricated external ECC jacketed composite column of the application is that the detection member between the bottom jacket single piece and the middle jacket single piece is a displacement sensor, and the displacement sensor is provided with a first alarm.

[0011] The further improvement of the prefabricated external ECC jacketed composite column of the application is that the detection member between the middle jacket single piece and the top jacket single piece is an acceleration sensor, and the acceleration sensor is provided with a second alarm.

[0012] The technical scheme of the application has the following beneficial effects: The prefabricated external ECC jacketed composite column of the application significantly improves the stress and strain level of the concrete in the column body through the synergistic effect of the prefabricated ECC jacket and the column body, thereby greatly enhancing the seismic performance. The multi-section ECC jacket design fundamentally solves the problem of the easy occurrence of penetrating cracks in the traditional reinforcement mode, ensures the continuous constraint effect of the jacket structure, and solves the technical problems of the structural column with the ECC jacket in the prior art, such as the easy occurrence of vertical penetrating cracks or local buckling damage under the action of load and the low seismic performance. The prefabricated component form of the application effectively avoids the construction difficulty of high maintenance and molding requirements of ECC material on site. The structure of the connecting assembly can effectively absorb and dissipate most of the buckling deformation that the ECC jacket may bear, prevent local damage and failure, significantly reduce the risk of large cracks in the ECC jacket under the action of an earthquake, and maintain the continuous constraint effect of the ECC jacket on the core concrete.

[0013] In addition to the purposes, features and advantages described above, the application has other purposes, features and advantages. The application will be further described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0014] The drawings that form a part of this application are used to provide a further understanding of the application, and the illustrative embodiments of the application and their description serve to explain the application without constituting an improper limitation of the application. In the drawings: Figure 1 is a sectional view of the prefabricated external ECC jacketed composite column of the application at the position of the connecting assembly; Figure 2 is a sectional view of the prefabricated external ECC jacketed composite column of the application at the position of the jacket single piece; Figure 3 is Figure 1 is a sectional view along A-A; Figure 4 is Figure 1 is a sectional view along B-B; Figure 5 is Figure 3 is a local enlarged view of the connecting assembly area; Figure 6 For Figure 4 Local enlarged view of the connection assembly area.

[0015] Wherein, 1, column body; 2, prefabricated ECC jacket mechanism; 21, bottom jacket single piece; 22, middle jacket single piece; 23, top jacket single piece; 3, spring; 4, detection piece; 41, displacement sensor; 42, acceleration sensor; 5, connecting frame body; 51, inner ring plate; 52, outer L-shaped plate; 53, outer T-shaped plate; 6, ring U-shaped plate; 7, longitudinal steel bar; 8, stirrup; 9, one layer of plane. DETAILED DESCRIPTION

[0016] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0017] Referring to Figures 1-6 As shown in the figure, a prefabricated external ECC jacket combined column comprises a column body 1 and a prefabricated ECC jacket mechanism 2, and the prefabricated ECC jacket mechanism 2 is located at the plastic hinge area of the column body 1. The prefabricated ECC jacket mechanism 2 comprises a plurality of jacket single pieces and a plurality of connection assemblies, the plurality of jacket single pieces are fixed to the outer periphery of the column body 1 in a spaced sleeve manner, and the connection assembly is connected between adjacent two jacket single pieces. The connection assembly comprises a connecting frame body 5, a damping piece and a detection piece 4, the damping piece and the detection piece 4 are installed inside the connecting frame body 5, and the jacket single piece is inserted and fixed in the connecting frame body 5 from both ends.

[0018] Specifically, the column body 1 is a cast-in-place reinforced concrete structure, and the column body 1 is provided with longitudinal steel bars 7 and stirrups 8. The entire prefabricated ECC jacket mechanism 2 is manufactured and installed in the factory, and when the site construction is carried out, a groove for installing the prefabricated ECC jacket mechanism 2 is left on the one layer of plane 9 or other parts, the prefabricated ECC jacket mechanism 2 is inserted into the groove and installed and fixed after adding structural adhesive, and finally the column body 1 is formed by pouring concrete on site in the prefabricated ECC jacket mechanism 2. The jacket is prefabricated from ECC material, and the compressive strength of the ECC material should be ensured to be about 1.2~2 times of that of ordinary concrete, and should not be more than 3 times of that of ordinary concrete.

[0019] Preferably, as Figures 3-6As shown, the cross section of the connecting frame body 5 is H-shaped, and a middle part of the connecting frame body 5 is formed with a receiving chamber in which the damping member and the detection member 4 are installed. The outer side of the receiving chamber is not sealed for buffering the deformation of the column 1 when an earthquake occurs. The entire connecting frame body 5 is made of steel plates to improve the overall strength of the prefabricated external ECC jacketed composite column. When the seismic requirement is relatively low, Q235B steel can be used, and when the seismic requirement is high, Q335B steel can be used. The welding of the steel should avoid welding fatigue, and butt welding and a transition smooth weld shape can be used to avoid sharp notches.

[0020] Preferably, the connecting frame body 5 includes an inner ring-shaped plate 51, an outer L-shaped plate 52, and an outer T-shaped plate 53. The inner ring-shaped plate 51 is sleeved and fixed to the outer periphery of the column 1. The inner surface of the inner ring-shaped plate 51 is connected with the cast-in-place concrete column 1, and the outer surface is connected with the jacket single piece. The surface of the inner ring-shaped plate 51 is roughened to enhance the bonding stress with the cement-based material. The thickness of the inner ring-shaped plate 51 is 1 cm, the outer diameter is the diameter of the column 1, and the height is 15-25 cm.

[0021] The outer L-shaped plate 52 is fixed to the inner ring-shaped plate, and a first space for inserting and installing the jacket single piece is formed between the outer L-shaped plate 52 and the lower part of the inner ring-shaped plate. The short side length of the outer L-shaped plate 52 is the thickness of the jacket single piece, and the long side length is about 7 cm. The short side needs to be welded and connected with the inner ring-shaped plate 51. The outer L-shaped plate 52 is located on the outer side of the jacket single piece, and the inner side surface needs to be roughened to increase the bonding stress with the ECC jacket. The outer L-shaped plate 52 forms a groove structure with the inner ring-shaped plate 51 by welding to increase the connection with the jacket single piece.

[0022] The outer T-shaped plate 53 is fixed to the inner ring-shaped plate, and a second space for inserting and installing the jacket single piece is formed between the outer T-shaped plate 53 and the upper part of the inner ring-shaped plate. The outer T-shaped plate 53 and the middle part of the inner ring-shaped plate form the receiving chamber. The thickness of the entire connecting frame body 5 is 1 cm. The web length of the outer T-shaped plate 53 is the thickness of the jacket single piece, and the lengths of the two side flanges are not equal, one being 8 cm long and the other being 4 cm long. The inner side surface of the outer T-shaped plate 53 is roughened to increase the bonding stress with the jacket single piece. The outer T-shaped plate 53 forms a groove structure with the inner ring-shaped plate 51 by welding to increase the connection with the jacket single piece.

[0023] Preferably, an annular U-shaped plate 6 is fixed to the outside of the turning point of the outer L-shaped plate 52. The lower flange of the outer T-shaped plate 53 is inserted into the annular U-shaped plate 6, with a gap between the end of the lower flange of the outer T-shaped plate 53 and the bottom wall of the annular U-shaped plate 6. Specifically, the shorter side wing of the outer T-shaped plate 53 is inserted into the concave steel channel to a depth of approximately 2 cm. The thickness of the annular U-shaped plate 6 is 0.5 cm, and the height of the gap is approximately 2.5 cm, which is used to cushion the deformation of the column 1 during earthquakes.

[0024] Preferably, the shock absorber is a spring 3, which is located in the accommodation space formed by the inner annular plate 51, the outer L-shaped plate 52 and the outer T-shaped plate 53. In this embodiment, the net height of the accommodation space is about 5 cm. Figure 1 As shown, there are 20 shock-absorbing springs 3 in the accommodating space. The springs 3 are evenly distributed in the closed area, and the two ends of the springs 3 are respectively connected to the two ends of the outer L-shaped plate 52 and the outer T-shaped plate 53.

[0025] Spring 3 needs to set its appropriate stiffness coefficient and preload according to the seismic fortification intensity of the project location. The stiffness coefficient needs to be considered according to the seismic fortification intensity. When an earthquake occurs, the superior frequency of the earthquake ( )for: ; Spring 3 is designed based on a rigid structure to reduce seismic response, and the natural frequency of the shock-absorbing spring 3 ( ) is considered to be twice the dominant frequency of the earthquake. When designing the shock absorbing spring 3, the stiffness coefficient of the spring 3 is It is calculated by the following formula: ; in, For the outstanding frequency of earthquakes, is the characteristic period of the earthquake; is the mass of the upper jacket of the shock-absorbing spring 3 and the outer T-shaped plate 53; the spring 3 is a parallel spring 3 in each layer, so the stiffness coefficient of a single spring 3 is k / 20; the preload value of the spring 3 under different seismic fortification intensities β Use the following formula to calculate: ; in, is the acceleration due to gravity.

[0026] Preferably, Figure 3 and Figure 4As shown, the number of the jacket single pieces is three, the three jacket single pieces are arranged at intervals along the length direction of the column 1, and the three independent jacket single pieces are respectively endowed with different heights due to the stress characteristics of the column 1 under the action of the earthquake. The bottom jacket single piece 21 needs to be inserted into a layer of plane 9 by 10 cm, and is fixed with the cast-in-situ concrete on the inside and is fixed with a layer of plane 9 on the outside through structural glue, so as to improve the integrity of the ECC jacket and the concrete structure. When the structural glue is connected, the thickness of the structural glue is controlled to be about 3-5 mm, and too small will affect the bonding strength, and too large will prolong the bonding time. The height of the bottom jacket single piece 21 : ; wherein, is the height of the column, is the tensile strength of the longitudinal reinforcement 7, is the diameter of the longitudinal reinforcement 7; the height of the middle jacket single piece 22 and the height of the top jacket single piece 23 are respectively: ; ; wherein, is the width of the column section.

[0027] The three independent external jacket single pieces can avoid the through cracks of the jacket and affect the use efficiency. The inner sides of the three jacket single pieces are all roughened, so as to be closely bonded with the cast-in-situ concrete column 1 on the inside. The bottom of the bottom jacket single piece 21 is closely connected with a layer of plane 9 through structural glue, and the top end is closely connected with the outer L-shaped plate 52 through structural glue. The upper and lower ends of the middle jacket single piece are closely connected with the upper outer L-shaped plate 52 and the lower outer T-shaped plate 53 through structural glue. The lower end of the top jacket single piece is closely connected with the outer T-shaped plate 53 through structural glue. The thickness of the jacket single piece is 50-80 mm. The number of the connecting assemblies in the embodiment is two, which are distributed at the two ends of the middle jacket single piece.

[0028] Preferably, the detection piece 4 between the bottom jacket single piece 21 and the middle jacket single piece 22 is a displacement sensor 41, and the displacement sensor 41 is provided with a first alarm. The displacement sensor 41 is used for monitoring deformation. When the displacement deformation reaches 1 cm when the earthquake occurs, the internal first alarm will trigger a warning signal, and when the deformation reaches 2 cm, an emergency alarm signal will be sent.

[0029] Preferably, the detecting member 4 between the middle jacket single piece 22 and the top jacket single piece 23 is an acceleration sensor 42, and the acceleration sensor 42 is provided with a second alarm. The number of displacement sensors 41 and acceleration sensors 42 is four, and one is arranged in the middle of each of the four faces of the column. The acceleration sensor 42 is used to monitor acceleration, and the second alarm sends a pre-warning signal when the acceleration is 0.1g (g is the acceleration of gravity) when an earthquake occurs, and an emergency alarm signal when the acceleration is 0.2g.

[0030] The built-in displacement sensor 41 and the acceleration sensor 42 of the application can monitor the deformation of the column 1 in real time, intelligently issue a graded pre-warning signal according to the degree of deformation, provide reliable protection for earthquake emergency response, effectively improve the structural safety protection capability, and effectively protect the safety of life and property.

[0031] The prefabricated external ECC jacket combined column of the application significantly improves the stress and strain level of the concrete in the column 1 through the synergistic effect of the prefabricated ECC jacket and the column 1, thereby greatly enhancing the seismic performance. The multi-section ECC jacket design fundamentally solves the problem of easy penetration cracks in traditional reinforcement methods, ensures the continuous constraint effect of the jacket structure, and solves the technical problems of the structural column with an ECC jacket in the prior art, which is prone to premature vertical penetration cracks or local buckling failure under load and has low seismic performance. The prefabricated component form of the application effectively avoids the construction difficulties of high maintenance and molding requirements of ECC materials on site. The structure of the connecting assembly can effectively absorb and dissipate most of the buckling deformation that the ECC jacket may bear, prevent local damage and failure, significantly reduce the risk of large cracks in the ECC jacket under seismic action, and maintain its continuous constraint effect on the core concrete.

[0032] The finite element analysis results of the comparison of the seismic performance of the prefabricated external ECC jacket combined column of the application and the traditional external ECC jacket combined column are as follows: The modeling method of the model used in the comparison process refers to the Concrete Structure Design Standard (GB / T 50010-2010 (2024 edition)), Mander model (used to describe the stress-strain relationship of concrete under transverse steel reinforcement constraint), Clough steel reinforcement constitutive model (used to describe the damage accumulation of steel reinforcement in the process of cyclic loading), etc. The model has been tested and verified, and the error is less than 5%. The specific method is as follows: The cross-sectional size of the column member used is 350*350mm, and the column height is 3000mm. The height of the conventional ECC jacket used is 800mm, and the jacket thickness is 50mm, which is simply wrapped in the plastic hinge zone at the bottom of the column during implementation. The structure of the application uses a three-section ECC jacket, and the sum of the heights of the three sections is 800mm, and the jacket thickness is 50mm. When performing seismic performance analysis, two kinds of constant vertical axial compression ratios are compared, and the axial compression ratios are 0.2 and 0.6 respectively, and the horizontal loading is controlled by displacement. In addition, the horizontal displacement loading increment of each level is 5mm, and each level is cycled twice, and the loading is stopped until 50mm. Compared with ordinary concrete columns, the following compares the increments of the seismic performance improvement of two different ECC jacket composite columns under two axial compression ratios, and the specific results are as follows:

[0033] From the above data comparison, compared with the traditional external ECC jacket, the external ECC jacket of the application has more obvious improvement on the seismic performance of the column, especially in the improvement of cumulative energy dissipation, and the improvement increment is more than one time of the traditional external ECC jacket. Further, it also shows that the multi-section prefabricated external ECC jacket composite column has the prospect of engineering promotion.

[0034] The above only describes the preferred embodiments of the application and is not intended to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A precast composite column with external ECC jacketing, characterized in that, The utility model relates to a column (1) and prefabricated ECC jacket mechanism (2) are included in the plastic hinge area of column (1), the prefabricated ECC jacket mechanism (2) includes a plurality of jacket single piece and a plurality of connecting components, a plurality of jacket single piece is fixed to the outer periphery of column (1) with interval cover, and the connecting component is connected between adjacent two jacket single pieces. The connecting component includes connecting frame body (5), damping piece and detection piece (4), the damping piece and the detection piece (4) are installed in the connecting frame body (5), and the jacket single piece is inserted and fixed in the connecting frame body (5) from both ends. The connecting frame body (5) is H-shaped in section, and a receiving chamber is formed in the middle of the connecting frame body (5), and the damping piece and the detection piece (4) are installed in the receiving chamber.

2. The precast ECC-encased column with exterior post-tensioning system of claim 1, wherein, The connecting frame body (5) includes an inner side ring type plate (51), an outer side L type plate (52) and an outer side T type plate (53), the inner side ring type plate (51) is fixed to the outer periphery of the column (1) with interval cover.

3. The precast ECC-encased column with exterior post-tensioning system of claim 2, wherein, The outer side L type plate (52) is fixed to the inner side ring type plate, and a first space is formed between the outer side L type plate (52) and the lower part of the inner side ring type plate for inserting and installing the jacket single piece. The outer side T type plate (53) is fixed to the inner side ring type plate, and a second space is formed between the outer side T type plate (53) and the upper part of the inner side ring type plate for inserting and installing the jacket single piece, and the receiving chamber is formed between the outer side T type plate (53) and the middle part of the inner side ring type plate. The outer side of the turning part of the outer side L type plate (52) is fixed with a ring-shaped U type plate (6), the lower flange plate of the outer side T type plate (53) is inserted into the ring-shaped U type plate (6), and the end of the lower flange plate of the outer side T type plate (53) has a gap with the bottom wall of the ring-shaped U type plate (6).

4. The precast ECC-encased column with exterior post-tensioning system of claim 3, wherein, The detection piece (4) between the bottom jacket single piece (21) and the middle jacket single piece (22) is a displacement sensor (41), and a first alarm is arranged in the displacement sensor (41).

5. The precast ECC-encased column with exterior post- installed ECC jacketing of claim 3, wherein, The damping member is a spring (3) whose stiffness coefficient is calculated from the formula: ； ； wherein, is the predominant frequency of the earthquake, is the characteristic period of the earthquake; is the mass of the upper sleeve single piece and the outer T-shaped plate (53) of the shock absorbing spring (3); the pre-pressing amount of the spring (3) set under different seismic fortification intensities β is calculated using the following formula: ； wherein is the gravitational acceleration.

6. The precast ECC-encased column with exterior post-tensioning wrap of claim 1, wherein, The number of the jacket single pieces is three, the three jacket single pieces are arranged at intervals along the length direction of the column body (1), the height of the bottom jacket single piece (21) is greater than the height of the top jacket single piece (22) : ； in, is the height of the column, is the tensile strength of the longitudinal reinforcement (7), is the diameter of the longitudinal reinforcement (7); the height of the middle jacket single piece (22) and the height of the top jacket single piece (23) respectively: ； ； wherein is the width of the column cross-section.

7. The precast ECC-encased column with exterior post-tensioning wrap of claim 6, wherein, The detection piece (4) between the middle jacket single piece (22) and the top jacket single piece (23) is an acceleration sensor (42), and a second alarm is arranged in the acceleration sensor (42).

8. The precast ECC-encased column with exterior post-tensioning wrap of claim 6, wherein, ​

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