Composite structure for reinforcing existing concrete frame through externally-attached self-resetting supporting frame and construction method

Abstract

The invention discloses a mixed structure for reinforcing an existing concrete frame through an externally-attached self-resetting supporting frame and a construction method. The mixed structure is composed of the externally-attached self-resetting supporting frame, a prefabricated composition board and the existing concrete frame. Wherein the externally attached self-resetting supporting frame, the prefabricated composition board and the existing reinforced concrete frame are sequentially connected through pre-embedded U-shaped bolts and post-embedded anchor bolts. The externally-attached self-resetting supporting frame is composed of a prefabricated prestressed concrete column, a prefabricated prestressed hybrid beam, a self-resetting steel support and a prefabricated foundation. Wherein the prefabricated prestressed hybrid beams are connected with the prefabricated prestressed concrete columns through bolts; the prefabricated prestressed concrete column is connected with the prefabricated foundation through an embedded anchor bolt; the self-resetting steel supports are connected with the prefabricated prestressed concrete columns and the prefabricated prestressed hybrid beams through pin shafts, and in addition, the invention further provides a construction method of the frame. According to the invention, the low-disturbance, toughness and green anti-seismic enhancement of the existing concrete frame building can be effectively realized.

Description

Technical Field

[0001] The present invention belongs to the field of building technology, and particularly relates to a hybrid structure for strengthening an existing concrete frame with an externally attached self-centering bracing frame and a construction method thereof. Background Art

[0002] Due to limited early seismic design and construction levels, insufficient mechanical properties of materials, as well as factors such as later changes in service functions and unreasonable reconstructions, a large number of existing reinforced concrete frame structures have been severely damaged in previous earthquakes, with a large number of overall collapses, weak story failures, and local damages occurring. In addition, according to existing standards, the prerequisite for the seismic resilience rating of a reinforced concrete frame structure is that the maximum story residual drift ratio in the inelastic time history analysis under rare earthquakes should be less than or equal to 0.5%, resulting in the seismic performance of a large number of existing reinforced concrete frame structures being unable to meet the basic seismic requirements and resilience evaluation requirements. In addition, traditional local strengthening methods (such as the method of increasing cross-section, replacing concrete, and encasing) are contradictory to the design principle of "strengthening the structural integrity and preventing local strengthening" emphasized in the Technical Specification for Seismic Strengthening of Buildings. Moreover, the construction process of the traditional strengthening method of "removing interior decoration - strengthening - redecorating" will block the use function of the building, causing waste of resources and excessive time consumption. In view of the problems of the traditional seismic strengthening method, such as great interference with the use function of the building, high costs of relocation and redecoration, etc., the externally attached substructure strengthening method has been proposed, which specifically refers to reasonably attaching substructures such as braces, frames, bracing frames, or shear walls to the outside of the existing structure to improve the seismic performance of the existing structure. However, the existing externally attached substructure strengthening method has problems such as complex construction of the cast-in-place concrete construction mode for substructures and connection domains, insufficient reset ability of substructures, unclear shear force transfer mechanism between structures, unclear strength and stiffness matching relationship between structures, and connectors invading the interior of the existing structure, greatly weakening the advantages of this strengthening method. Summary of the Invention

[0003] In order to overcome the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a hybrid structure for strengthening an existing concrete frame with an externally attached self-centering bracing frame and a construction method thereof. It retains the advantages of the existing externally attached substructure for strengthening an existing concrete frame, and at the same time solves its technical deficiencies. The hybrid structure for strengthening an existing concrete frame with an externally attached self-centering bracing frame has three performance advantages: the function is not interfered during the construction process of the externally attached substructure strengthening method, the function can be restored after the earthquake for the externally attached self-centering substructure, and the prefabricated assembly technology is green and efficient. It can effectively improve the vertical lateral stiffness distribution pattern of the existing concrete frame structure, reduce the residual deformation after the earthquake, and achieve the purpose of "new and old structures" cooperating in seismic resistance, and can effectively realize the low-interference, ductile, and green seismic enhancement of the existing concrete frame.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0005] An externally attached self - resetting support frame for strengthening an existing concrete frame hybrid structure, comprising an externally attached self - resetting support frame and a precast composite slab. Among them, the externally attached self - resetting support frame and the precast composite slab are connected by U - shaped bolts embedded in the precast prestressed hybrid beam in the externally attached self - resetting support frame, and the existing concrete frame and the precast composite slab are connected by post - implanted anchor bolts installed on the surface of the frame beam in the existing concrete frame.

[0006] The externally attached self - resetting support frame mainly includes four parts: precast prestressed concrete columns, precast prestressed hybrid beams, self - resetting steel supports, and precast foundations. Among them, the precast prestressed concrete columns and the precast foundations are connected by L - shaped anchor bolts embedded in the precast foundations, the precast prestressed concrete columns and the precast prestressed hybrid beams are connected by bolt one, and the self - resetting steel supports are connected to both the precast prestressed concrete columns and the precast prestressed hybrid beams by pin shafts.

[0007] The precast composite slab includes a perforated outer steel frame, a sandwich steel plate welded inside the outer steel frame, headed stud welds two welded on the upper and lower surfaces of the sandwich steel plate and arranged uniformly, a steel bar mesh one arranged inside the outer steel frame, and precast concrete four filled inside the outer steel frame.

[0008] The precast prestressed concrete column includes a precast concrete column arranged in the middle, a perforated column bottom plate arranged at the bottom of the precast concrete column, prestressing tendon one arranged inside the precast concrete column, an anchor plate arranged at the top of the precast concrete column, and an anchor one arranged outside the anchor plate.

[0009] The precast concrete column includes longitudinal bars one, stirrups one, embedded pipe one arranged along the column axis direction, embedded pipe two arranged in the column joint core area and perpendicular to the column axis direction, square steel pipe one, column foot steel boot, and precast concrete one.

[0010] The column foot steel boot is composed of square steel pipe two, connecting ear plates, and a perforated bottom plate welded together.

[0011] The precast prestressed hybrid beam includes a short steel beam arranged at the end, a precast concrete beam arranged in the middle, prestressing tendon two arranged along the beam axis direction, an anchor two arranged at one end of the prestressing tendon two, an anchor three arranged at the other end of the prestressing tendon two, a friction plate one arranged between the web of the short steel beam and the extended plate of the precast concrete beam, and bolt two for connecting the short steel beam and the precast concrete beam.

[0012] The short steel beam is composed of a web - perforated section steel, end plate one, anchor plate (, anchor plate stiffener plate, and a perforated cover plate welded together.

[0013] The precast concrete beam includes end connectors, mid-span connectors, longitudinal reinforcement II, stirrups II, embedded pipes III arranged along the beam axis, embedded U-shaped bolts, and precast concrete II. The end connectors are welded and composed of extended plates, end plates II, steel section segments, and headed stud welds II. The mid-span connectors are welded and composed of flat plates, connecting steel bars, connecting plates, and stiffening ribs.

[0014] The self-centering steel brace includes pre-compressed disc spring groups, guiding bolts arranged inside the disc spring groups, anchoring plates arranged at both ends of the disc spring groups, bolts III passing through the anchoring plates and arranged staggeredly, inner cylinder connectors, outer cylinder connectors, friction plates II, and bolts IV. The inner cylinder connectors are welded and composed of inner clamping steel plates with oval long holes, inner square steel cylinders, inner cylinder support pipes, inner cylinder end plates, extended steel section I, steel section end plates I, and extended ear plates I. The outer cylinder connectors are welded and composed of outer clamping steel plates with round holes, outer square steel cylinders, outer cylinder support pipes, outer cylinder end plates, extended steel section II, steel section end plates II, and extended ear plates II.

[0015] The precast foundation includes steel bar mesh II arranged at the bottom, embedded anchor bolts arranged vertically, bearing plates with holes in the center arranged at one end of the embedded anchor bolts, and precast concrete III.

[0016] The precast prestressed concrete columns, precast prestressed composite beams, self-centering steel braces, precast foundations, and precast composite slabs are all precast components and are all produced and fabricated in factories in a standardized manner.

[0017] The prestressing tendon I and the anchor I can adopt the combination of a circular wedge anchor and a steel strand or the combination of a precision rolled thread steel bar and a matching nut according to the design requirements. The prestressing tendon II adopts a steel strand. The anchor II adopts a single-hole circular wedge anchor. The anchor III adopts a single-hole wedge type low-retraction anchor.

[0018] The friction plate I and the friction plate II can be made of materials such as brass, NAO non-asbestos organic materials, ceramics, carbon fiber, etc. according to the design requirements. The embedded pipes I, II, and III can adopt PVC pipes or metal corrugated pipes according to the design requirements. The post-embedded anchor bolts can adopt mechanical anchor bolts or chemical anchor bolts according to the design requirements.

[0019] The aperture of the oval long hole on the web of the steel section segment and the inner clamping steel plate should ensure that there is enough sliding space for the high-strength bolt II and the bolt IV under seismic loads. When pouring the precast concrete III for the precast foundation, appropriate space should be reserved under the square hole of the bearing plate with holes to meet the placement of the anchor I.

[0020] The construction method for the external attached self-centering support frame to reinforce the existing concrete frame hybrid structure system is as follows:

[0021] 1), At the factory, precast concrete columns, short steel beams, precast concrete beams, self-centering steel braces and precast composite slabs are fabricated with high precision. After the concrete strength reaches the standard, post-tensioned prestressing tendons are installed in the precast concrete columns according to the expected design values to complete the fabrication of precast prestressed concrete columns. After the short steel beams and precast concrete beams are preliminarily connected and fixed through friction plates and bolts two, post-tensioned prestressing tendons are installed in them according to the expected design values to complete the fabrication of precast prestressed composite beams.

[0022] 2), At the construction site, the outer surface of the connecting frame beam of the existing concrete frame is cleaned and holes are drilled to implant post-embedded anchor bolts. A foundation pit is excavated in a predetermined area outside the adjacent existing concrete frame and the foundation is strengthened, and then the precast foundation is hoisted and buried.

[0023] 3), At the construction site, the precast composite slab is hoisted to the outside of the connecting frame beam of the existing concrete frame and the connection between the two is completed by post-embedded anchor bolts. The precast prestressed concrete column is hoisted above the precast foundation and the connection between the two is completed by the L-shaped anchor bolts of the foundation.

[0024] 4), At the construction site, the precast prestressed composite beam is hoisted to the side of the precast composite slab and the connection with the precast prestressed concrete column and the precast composite slab is completed in sequence by bolts one and U-shaped bolts.

[0025] 5), At the construction site, the self-centering steel brace is hoisted into the precast frame composed of the precast prestressed concrete column and the precast prestressed composite beam and the connection is completed by pin shafts. Then, high-strength non-shrinkage grouting material is filled in the column top anchorage area of the precast prestressed concrete column, the reserved through slots in the precast composite slab and other gaps. After the strength reaches the standard, all the processes of strengthening the existing concrete frame with the externally attached self-centering brace frame can be completed.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) Outdoor reinforcement and organic renewal. Compared with the traditional seismic reinforcement method, the construction operations are all carried out outside the existing building, and the internal personnel and items do not need to be transferred. Moreover, the anchor bolt connectors between the structures do not invade the interior of the existing concrete frame, and an efficient renewal mode of "strengthening while in use" can be realized, meeting the urgent market demand for non-interference seismic reinforcement of existing concrete frames, especially more meeting the reinforcement requirements for the uninterrupted use functions of educational and hospital buildings, and significantly improving the engineering feasibility.

[0028] (2) Cooperative seismic resistance with controllable damage. Compared with the existing seismic reinforcement method of the external attached structure, the external attached structure adopts a self-centering support frame sub-structure composed of precast prestressed concrete columns, precast prestressed composite beams, self-centering steel braces and precast foundations. Among them, steel plates are embedded at the opening and closing interfaces where the column-foundation and the short steel beam-precast concrete beam are pre-pressed connected, which can effectively avoid collision damage at the opening and closing interfaces; the self-centering braces remain continuous at the center connection of the frame beams, which can avoid the damage of the cross beams caused by the unbalanced concentrated force at the mid-span of the cross beams when the braces deform; the elongation rate of the braces can be adjusted by adjusting the specifications and combination methods of the disc springs, which can avoid the problem of insufficient elongation rate caused by the limited length of the prestressed tendons in the traditional self-centering braces; the friction devices are all arranged externally, which can avoid the situation that the friction devices produce cold bonding or post-earthquake wear and cannot be inspected and replaced. In addition, the self-centering support frame and the existing concrete frame are connected by precast composite slabs to form a hybrid structure system of the external attached self-centering support frame for strengthening the existing concrete frame. The external attached self-centering support frame can provide lateral resistance, self-centering ability and energy dissipation ability for the existing concrete frame, improve the uneven lateral displacement mode of the existing concrete frame and significantly reduce the damage. Generally speaking, the external attached self-centering support frame increases the lateral stiffness of the overall structure and is more evenly distributed along the height, greatly improves the lateral resistance ability, effectively delays the appearance and development of surface cracks in the existing concrete frame, significantly reduces the post-earthquake residual deformation, and significantly enhances the recovery ability of the non-linear deformation.

[0029] (3) Green construction with remarkable benefits. Compared with other seismic reinforcement methods, the use of prefabricated assembly technology in the hybrid structure of the external attached self-centering support frame for strengthening the existing concrete frame can achieve efficient construction. The precast prestressed concrete columns, precast prestressed composite beams, self-centering steel braces, precast foundations and precast composite slabs in the external attached self-centering support frame are all prefabricated in the factory in advance. At the construction site, there are only processes such as implanting anchor bolts on the surface of the existing concrete frame, burying precast foundations and hoisting each component, and high-efficiency dry connection technologies such as anchor bolts, bolts or pin shafts are used between the components. Among them, the single-span beam is post-tensioned with prestressed tendons separately and then hoisted to connect with the column, which can avoid the complex and dangerous construction method of post-tensioning prestressed tendons across the span at high altitude in the traditional prestressed concrete frame. In addition, according to the differences in the external facades of different existing concrete frames, the precast composite slabs in the connection area can be customized according to the actual space requirements. It can be seen that the quality of each component in the hybrid structure of the external attached self-centering support frame for strengthening the existing concrete frame is easy to guarantee, the on-site installation is convenient and efficient, the labor cost is significantly reduced, only the external facade decoration layer of the existing concrete frame needs to be partially removed, and there is basically no resource waste, which conforms to the development trend of green reinforcement and is conducive to the sustainable development of the construction industry. Brief Description of the Drawings

[0030] Figure 1 It is a three-dimensional composition schematic diagram of a hybrid structure of an external attached self-centering support frame for strengthening an existing concrete frame according to the present invention.

[0031] Figure 2 It is a three-dimensional schematic diagram of a hybrid structure that strengthens an existing concrete frame with an externally attached self-centering support frame according to the present invention.

[0032] Figure 3 It is a plan schematic diagram of the externally attached self-centering support frame.

[0033] Figure 4 It is a three-dimensional composition schematic diagram of a precast prestressed concrete column.

[0034] Figure 5 It is a three-dimensional composition schematic diagram of a precast concrete column within a precast prestressed concrete column.

[0035] Figure 6 It is a three-dimensional composition schematic diagram of a precast prestressed concrete beam.

[0036] Figure 7 It is a three-dimensional composition schematic diagram of a precast concrete beam within a precast prestressed concrete beam.

[0037] Figure 8 It is a three-dimensional composition schematic diagram of a short steel beam within a precast concrete beam.

[0038] Figure 9 It is a three-dimensional composition schematic diagram of a mid-span connector within a precast concrete beam.

[0039] Figure 10 It is a three-dimensional composition schematic diagram of an end connector within a precast concrete beam.

[0040] Figure 11 It is a three-dimensional composition schematic diagram of a precast composite slab.

[0041] Figure 12 It is a three-dimensional composition schematic diagram of a self-centering steel brace.

[0042] Figure 13 It is a three-dimensional composition schematic diagram of an inner cylinder connector within a self-centering steel brace.

[0043] Figure 14 It is a three-dimensional composition schematic diagram of an outer cylinder connector within a self-centering steel brace.

[0044] Figure 15 It is a three-dimensional composition schematic diagram of a precast foundation.

[0045] Figure 16 It is a three-dimensional schematic diagram of the hoisting of a precast foundation at the construction site and the subsequent implantation of anchor bolts on the surface of an existing concrete frame beam.

[0046] Figure 17 It is a three-dimensional schematic diagram of the hoisting process of a precast composite slab and a precast prestressed concrete column at the construction site.

[0047] Figure 18 It is a three-dimensional schematic diagram of the hoisting process of precast prestressed composite beams at the construction site.

[0048] Figure 19 It is a three-dimensional schematic diagram of the hoisting process of self-centering steel braces at the construction site, the casting of post-cast concrete at the bolt connection of precast composite slabs, and the casting of grouted concrete at the anchor end of precast prestressed concrete column heads. Specific embodiments

[0049] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples.

[0050] As Figures 1 to 2 shown, the present invention is an externally attached self-centering support frame for strengthening an existing concrete frame composite structure, including an externally attached self-centering support frame 1 and precast composite slabs 2. Among them, the externally attached self-centering support frame 1 and the precast composite slabs 2 are connected by U-shaped bolts 1.2.2.6 embedded in the precast prestressed composite beams 1.2 of the externally attached self-centering support frame 1, and the existing concrete frame 3 and the precast composite slabs 2 are connected by post-implanted anchor bolts 101 installed on the surface of the frame beams in the existing concrete frame 3.

[0051] In the overall hybrid structure, the existing concrete frame 3 bears the vertical load, and the existing concrete frame 3 and the externally attached self-centering bracing frame 1 jointly bear the lateral load, and the externally attached self-centering bracing frame 1 provides the functions of resetting and energy dissipation, thereby effectively improving the stiffness distribution pattern of the existing concrete frame 3, reducing the residual deformation, achieving the purpose of "new and old structures" collaborative earthquake resistance after load shunting, and forming a hybrid structure system with the functions of bearing - energy dissipation - resetting. Specifically, it is manifested as follows: 1) Under small earthquakes and vertical loads, the overall structure is in an elastic state; 2) Under medium earthquakes, based on the superelastic deformation of the prestressing tendon 1 - 1.1.3, prestressing tendon 2 - 1.2.3 and precompressed disc spring group 1.3.1 in the externally attached self-centering bracing frame 1, the precompressed interfaces between the short steel beam 1.2.1 and the precast concrete beam 1.2.2 and between the steel shoe 1.1.1.6 at the column foot and the perforated column bottom plate 1.1.2 will break through the opening starting force, and then there will be continuous opening and closing around the top and bottom turning points of the interface and tend to return to the initial closed state. The self-centering steel brace 1.3 also synchronously undergoes axial tensile and compressive deformation and tends to return to the initial original length state. At the same time, the friction interfaces between the web of the short steel beam 1.2.1 and the friction plate 1 - 1.2.6 and between the friction plate 2 - 1.3.7 and the clip steel plate 1.3.5.1 will turn into slip friction to dissipate seismic energy after breaking through the static friction. The overall reaches the performance turning point and each component still remains in an elastic state. There are no obvious cracks on the surface of the existing concrete frame 3, and the residual deformation after the earthquake is almost zero; 3) Under large earthquakes, the top and bottom turning point areas of the short steel beam 1.2.1 in the externally attached self-centering bracing frame 1 undergo compressive yielding and enter the plastic state. Obvious bending cracks appear at the beam ends and column feet in the existing concrete frame 3 in sequence, and with the longitudinal reinforcement yielding, it also enters the plastic state. The overall structural resetting ability is weakened, but the residual displacement angle remains within the limit range of the ductility evaluation standard, and the energy dissipation ability is greatly enhanced. After the earthquake, replacing the short steel beam 1.2.1 and repairing the damaged area of the existing concrete frame 3 can restore the service function of the structure. Generally speaking, the externally attached self-centering bracing frame 1 increases the lateral stiffness of the overall structure and is more evenly distributed along the height, the lateral resistance ability is greatly improved, the appearance and development of cracks on the surface of the existing concrete frame 3 will be effectively postponed, the residual deformation after the earthquake is significantly reduced, and the recovery ability of non-linear deformation is significantly enhanced.

[0052] As Figure 3 shown, the externally attached self-centering bracing frame 1 includes four parts: a precast prestressed concrete column 1.1, a precast prestressed hybrid beam 1.2, a self-centering steel brace 1.3, and a precast foundation 1.4. Among them, the precast prestressed concrete column 1.1 is connected to the precast foundation 1.4 through the L-shaped anchor bolts 1.4.2 embedded in the precast foundation 1.4. The precast prestressed concrete column 1.1 is connected to the precast prestressed hybrid beam 1.2 through bolts 102. The self-centering steel brace 1.3 is connected to both the precast prestressed concrete column 1.1 and the precast prestressed hybrid beam 1.2 through pin shafts 103.

[0053] According to the above structure, in the present invention, the externally attached self-centering support frame 1 provides strong self-centering ability through the super-elastic deformation of the prestressed tendons and the precompressed disc spring group, and provides energy dissipation ability in stages through the slip friction of the friction interface in the precast prestressed composite beam 1.2 and the self-centering steel support 1.3 and the plastic deformation of the short steel beam 1.2.1. Therefore, the externally attached self-centering support frame 1 has the characteristics of "strong self-centering - two-stage energy dissipation".

[0054] As Figures 4 to 5 shown, the precast prestressed concrete column 1.1 includes a precast concrete column 1.1.1 arranged in the middle, a perforated column bottom plate 1.1.2 arranged at the bottom of the precast concrete column 1.1.1, a prestressed tendon 1.1.3 arranged in the precast concrete column 1.1.1, an anchor plate 1.1.4 arranged at the top of the precast concrete column 1.1.1, and an anchor 1.1.5 arranged outside the anchor plate 1.1.4; the precast concrete column 1.1.1 includes longitudinal bars 1.1.1.1, stirrups 1.1.1.2, a buried pipe 1.1.1.3 arranged along the column axis direction, a buried pipe 1.1.1.4 arranged in the column joint core area and perpendicular to the column axis direction, a square steel pipe 1.1.1.5, a column base steel boot 1.1.1.6, and precast concrete 1.1.1.7; the column base steel boot 1.1.1.6 is composed of a square steel pipe 1.1.1.6.1, a connecting ear plate 1.1.1.6.2, and a perforated bottom plate 1.1.1.6.3 welded together.

[0055] As Figures 6 to 10As shown in the figure, the precast prestressed composite beam 1.2 includes a short steel beam 1.2.1 arranged at the end, a precast concrete beam 1.2.2 arranged in the middle, a second prestressing tendon 1.2.3 arranged along the beam axis direction, an anchor 1.2.4 arranged at one end of the second prestressing tendon 1.2.3, an anchor 1.2.5 arranged at the other end of the second prestressing tendon 1.2.3, a first friction plate 1.2.6 arranged between the web of the short steel beam 1.2.1 and the extended plate 1.2.2.1.1 of the precast concrete beam 1.2.2, and a second bolt 1.2.7 for connecting the short steel beam 1.2.1 and the precast concrete beam 1.2.2; the short steel beam 1.2.1 is composed of a profiled steel with web holes 1.2.1.1, a first end plate 1.2.1.2, an anchor backing plate (1.2.1.3, an anchor backing plate stiffener 1.2.1.4, and a perforated cover plate 1.2.1.5 welded together; the precast concrete beam 1.2.2 includes an end connector 1.2.2.1, a mid-span connector 1.2.2.2, a second longitudinal bar 1.2.2.3, a second stirrup 1.2.2.4, a third embedded pipe 1.2.2.5 arranged along the beam axis direction, an embedded U-shaped bolt 1.2.2.6, and precast concrete two 1.2.2.7; the end connector 1.2.2.1 is composed of an extended plate 1.2.2.1.1, a second end plate 1.2.2.1.2, a profiled steel section 1.2.2.1.3, and a second stud with cylindrical head 1.2.2.1.4 welded together; the mid-span connector 1.2.2.2 is composed of a flat plate 1.2.2.2.1, a connecting bar 1.2.2.2.2, a connecting plate 1.2.2.2.3, and a stiffening rib 1.2.2.2.4 welded together.

[0056] As Figure 11 shown, the precast composite slab 2 includes a perforated outer steel frame 2.1, a sandwich steel plate 2.2 welded inside the outer steel frame 2.1, second studs with cylindrical head 2.3 welded on the upper and lower surfaces of the sandwich steel plate 2.2 and arranged evenly, a first steel bar mesh 2.4 arranged inside the outer steel frame 2.1, and precast concrete four 2.5 filled inside the outer steel frame 2.1.

[0057] According to the above structure, tenon-mortise shaped through grooves are reserved in the precast composite slab 2 of the present invention, mainly to provide space for the subsequent implantation of the anchor bolts 101 and the screwing of the nuts of the U-shaped bolts 1.2.2.6. After tightening the nuts, pouring a small amount of high-strength non-shrinking grouting material 104 can ensure the reliability of their connections with the existing concrete frame 3 and the externally attached self-centering support frame 1 respectively.

[0058] As Figures 12 to 14As shown in the figure, the self-centering steel brace 1.3 includes a pre-compressed disc spring group 1.3.1, a guiding bolt 1.3.2 arranged inside the disc spring group, anchoring plates 1.3.3 arranged at both ends of the disc spring group, bolts three 1.3.4 passing through the anchoring plates and arranged staggeredly, an inner cylinder connecting piece 1.3.5, an outer cylinder connecting piece 1.3.6, a friction plate two 1.3.7, and a bolt four 1.3.8. The inner cylinder connecting piece 1.3.5 is composed of an inner clamping steel plate 1.3.5.1 with an elliptical long hole, an inner square steel cylinder 1.3.5.2, an inner cylinder support pipe 1.3.5.3, an inner cylinder end plate 1.3.5.4, an extended section steel one 1.3.5.5, a section steel end plate one 1.3.5.6, and an outer extending ear plate one 1.3.5.7 welded together. The outer cylinder connecting piece 1.3.7 is composed of an outer clamping steel plate 1.3.7.1 with a round hole, an outer square steel cylinder 1.3.7.2, an outer cylinder support pipe 1.3.7.3, an outer cylinder end plate 1.3.7.4, an extended section steel two 1.3.7.5, a section steel end plate two 1.3.7.6, and an outer extending ear plate two 1.3.7.7. In addition, the self-centering steel brace 1.3 is arranged in an alternating pattern of "herringbone" and "V-shaped" along the height within a single span.

[0059] According to the above structure, in the present invention, the self-centering steel brace 1.3 is composed of a parallel connection of an internal pre-compressed disc spring group 1.3.1 and a friction interface composed of an external friction plate two 1.3.7 and an inner clamping steel plate 1.3.5.1. Through bolts three 1.3.4 and bolts four 1.3.8 that transfer force staggeredly on both sides of the pre-compressed disc spring group 1.3.1, the purpose is achieved that the pre-compressed disc spring group 1.3.1 undergoes compressive deformation under both tensile and compressive states, thereby providing a stable deformation recovery ability.

[0060] As Figure 15 shown in the figure, the precast foundation 1.4 includes a steel bar mesh two 1.4.1 arranged at the bottom, vertically arranged embedded anchor bolts 1.4.2, a supporting plate 1.4.3 arranged at one end of the embedded anchor bolts 1.4.2 and with a hole in the center, and precast concrete three 1.4.4. It should be noted that in the present invention, the precast foundation 1.4 can adopt a precast stepped independent foundation or a sloping independent foundation, and the purpose is to evenly transfer the load of the upper structure to the foundation.

[0061] According to the above structure, the precast prestressed concrete column 1.1, precast prestressed composite beam 1.2, self-centering steel brace 1.3, precast foundation 1.4 and precast composite slab 2 in the present invention are all precast components, which are all produced and fabricated in the factory in a standardized manner. The prestressing tendon 1 1.1.3 and the anchor 1 1.1.5 can adopt the combination of a circular wedge anchor and a steel strand or the combination of a precision rolled thread steel and a matching nut according to the design requirements; the prestressing tendon 2 1.2.3 adopts a steel strand; the anchor 2 1.2.4 adopts a single-hole circular wedge anchor; the anchor 3 1.2.5 adopts a single-hole wedge-type low-relaxation anchor. The friction plate 1 1.2.6 and the friction plate 2 1.3.7 can be made of materials such as brass, NAO non-asbestos organic material, ceramic, carbon fiber, etc. according to the design requirements; the embedded pipe 1 1.1.1.3, the embedded pipe 2 1.1.1.4 and the embedded pipe 3 1.2.2.5 can adopt a PVC pipe or a metal corrugated pipe according to the design requirements; the post-implanted anchor bolt 101 can adopt a mechanical anchor bolt or a chemical anchor bolt according to the design requirements. The aperture of the oval long hole on the web of the steel section 1.2.2.1.3 and the inner sandwich steel plate 1.3.5.1 should ensure that there is enough slip space for the high-strength bolt 2 1.2.7 and the bolt 4 1.3.8 under the seismic load; when pouring the precast concrete 3 1.4.4 for the precast foundation 1.4, an appropriate space should be reserved under the square hole of the perforated tray 1.4.3 to meet the placement of the anchor 1 1.1.5.

[0062] An external attached self-centering brace frame for strengthening an existing concrete frame hybrid structure system of the present invention adopts an innovative construction concept of "applying prestress inside the components first and then dry connecting between the components", and the actual construction steps are as follows:

[0063] 1), In the factory, the precast concrete column 1.1.1, short steel beam 1.2.1, precast concrete beam 1.2.2, self-centering steel brace 1.3 and precast composite slab 2 are fabricated with high precision. After the concrete strength reaches the standard, the prestressing tendon 1 1.1.3 is post-tensioned in the precast concrete column 1.1.1 according to the expected design value to complete the production of the precast prestressed concrete column 1.1. After the short steel beam 1.2.1 and the precast concrete beam 1.2.2 are preliminarily connected and fixed through the friction plate 1 1.2.6 and the bolt 2 1.2.7, the prestressing tendon 2 1.2.3 is post-tensioned in it according to the expected design value to complete the production of the precast prestressed composite beam 1.2.

[0064] 2), As Figure 16 shown, at the construction site, after cleaning the outer surface of the frame beam to be connected of the existing concrete frame 3, holes are drilled and the post-implanted anchor bolts 101 are installed. A foundation pit is excavated in a predetermined area outside the adjacent existing concrete frame 3, and the foundation is strengthened, and then the precast foundation 1.4 is hoisted and buried;

[0065] 3), As Figure 17As shown in the figure, at the construction site, the precast composite slab 2 is hoisted to the outside of the connecting frame beam of the existing concrete frame 3, and the connection between the two is completed by post-embedded anchor bolts 101. The precast prestressed concrete column 1.1 is hoisted above the precast foundation 1.4, and the connection between the two is completed by the L-shaped anchor bolts 1.4.2 of the foundation.

[0066] 4), as Figure 18 shown in the figure, at the construction site, the precast prestressed composite beam 1.2 is hoisted to the side of the precast composite slab 2, and the connection with the precast prestressed concrete column 1.1 and the precast composite slab 2 is completed by bolt 102 and U-shaped bolt 1.2.2.6 in sequence.

[0067] 5), as Figure 19 shown in the figure, at the construction site, the self-centering steel brace 1.3 is hoisted into the precast frame composed of the precast prestressed concrete column 1.1 and the precast prestressed composite beam 1.2, and the connection is completed by pin 103. Then, high-strength non-shrinkage grouting material 104 is filled in the column top anchorage area of the precast prestressed concrete column 1.1, the reserved through slots in the precast composite slab 2, and other gaps. After the strength meets the standard, all the processes of strengthening the existing concrete frame 3 with the externally attached self-centering brace frame 1 can be completed.

[0068] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An existing concrete frame hybrid structure reinforced with an external self-resetting support frame, characterized in that: It comprises an external self-resetting support frame (1) and a prefabricated composite panel (2); The external self-resetting support frame (1) comprises a prefabricated prestressed concrete column (1.1), a prefabricated prestressed hybrid beam (1.2), a self-resetting steel support (1.3) and a prefabricated foundation (1.4); the prefabricated prestressed concrete column (1.1) is connected to the prefabricated foundation (1.4) via an L-shaped anchor bolt (1.4.2) pre-buried in the prefabricated foundation (1.4); the prefabricated prestressed concrete column (1.1) is connected to the prefabricated prestressed hybrid beam (1.2) via a bolt (102); and the self-resetting steel support (1.3) is connected to the prefabricated prestressed concrete column (1.1) and the prefabricated prestressed hybrid beam (1.2) via a pin shaft (103); The external self-resetting support frame (1) is connected to the prefabricated composite panel (2) via U-shaped bolts (1.2.2.6) embedded in a prefabricated prestressed hybrid beam (1.2) in the external self-resetting support frame (1), and the existing concrete frame (3) is connected to the prefabricated composite panel (2) via post-implanted anchor bolts (101) installed on the surface of the frame beam in the existing concrete frame (3).

2. According to claim 1, the existing concrete frame hybrid structure reinforced with an external self-resetting support frame is characterized by: The precast prestressed concrete column (1.1) comprises a precast concrete column (1.1.1) arranged in the middle, a column bottom end plate (1.1.2) with holes arranged at the bottom of the precast concrete column (1.1.1), a prestressed tendon (1.1.3) arranged in the precast concrete column (1.1.1), an anchor plate (1.1.4) arranged at the top of the precast concrete column (1.1.1), and an anchor (1.1.5) arranged outside the anchor plate (1.1.4); The precast concrete column (1.1.1) comprises a longitudinal reinforcement (1.1.1.1), a stirrup (1.1.1.2), a precast pipe (1.1.1.3) arranged along the column axis, a precast pipe (1.1.1.4) arranged in the core area of ​​the column node and perpendicular to the column axis, a square steel pipe (1.1.1.5), a column foot steel boot (1.1.1.6) and a precast concrete (1.1.1.7); The column foot steel boot (1.1.1.6) is welded together by a square steel pipe (1.1.1.6.1), a connecting ear plate (1.1.1.6.2) and a bottom plate with holes (1.1.1.6.3).

3. The existing concrete frame hybrid structure reinforced with an external self-resetting support frame according to claim 2 is characterized in that: The prefabricated prestressed hybrid beam (1.2) comprises a short steel beam (1.2.1) arranged at the end, a prefabricated concrete beam (1.2.2) arranged in the middle, two prestressed tendons (1.2.3) arranged along the beam axis, two anchors (1.2.4) arranged at one end of the two prestressed tendons (1.2.3), three anchors (1.2.5) arranged at the other end of the two prestressed tendons (1.2.3), a friction plate (1.2.6) arranged between the web of the short steel beam (1.2.1) and the overhanging plate (1.2.2.1.1) of the prefabricated concrete beam (1.2.2), and two bolts (1.2.7) for connecting the short steel beam (1.2.1) and the prefabricated concrete beam (1.2.2); The short steel beam (1.2.1) is welded together by a web perforated steel section (1.2.1.1), an end plate (1.2.1.2), an anchor plate (1.2.1.3), an anchor plate stiffening plate (1.2.1.4) and a perforated sealing plate (1.2.1.5); The precast concrete beam (1.2.2) comprises an end connector (1.2.2.1), a mid-span connector (1.2.2.2), two longitudinal reinforcements (1.2.2.3), two stirrups (1.2.2.4), three embedded pipes (1.2.2.5) arranged along the beam axis, embedded U-shaped bolts (1.2.2.6) and two precast concretes (1.2.2.7); the end connector (1.2.2.1) is formed by an external The extension plate (1.2.2.1.1), the second end plate (1.2.2.1.2), the steel section (1.2.2.1.3) and the second cylindrical head welding nail (1.2.2.1.4) are welded together; the mid-span connecting piece (1.2.2.2) is welded together with a plane plate (1.2.2.2.1), connecting steel bars (1.2.2.2.2), a connecting plate (1.2.2.2.3) and a stiffening rib (1.2.2.2.4).

4. The existing concrete frame hybrid structure reinforced with an external self-resetting support frame according to claim 3 is characterized by: The self-resetting steel support (1.3) comprises a preloaded disc spring group (1.3.1), a guide bolt (1.3.2) arranged inside the disc spring group, anchor plates (1.3.3) arranged at both ends of the disc spring group, three bolts (1.3.4) passing through the anchor plates and arranged in a staggered manner, an inner cylinder connecting piece (1.3.5), an outer cylinder connecting piece (1.3.6), a friction plate two (1.3.7) and a bolt four (1.3.8); the inner cylinder connecting piece (1.3.5) comprises an inner clamping steel plate with an elliptical long hole (1.3.5.1), an inner square steel cylinder (1.3.5.2), an inner cylinder support tube ( 1.3.5.3), inner tube end plate (1.3.5.4), extended steel section one (1.3.5.5), steel section end plate one (1.3.5.6) and outward extension ear plate one (1.3.5.7) are welded together; the outer tube connecting piece (1.3.7) is welded together with an outer clamping steel plate with a circular hole (1.3.7.1), an outer square steel tube (1.3.7.2), an outer tube support pipe (1.3.7.3), an outer tube end plate (1.3.7.4), extended steel section two (1.3.7.5), steel section end plate two (1.3.7.6) and outward extension ear plate two (1.3.7.7).

5. The existing concrete frame hybrid structure reinforced with an external self-resetting support frame according to claim 4 is characterized in that: The prefabricated foundation (1.4) comprises a steel mesh 2 (1.4.1) arranged at the bottom, a vertically arranged embedded anchor bolt (1.4.2), a support plate (1.4.3) arranged at one end of the embedded anchor bolt (1.4.2) and having a hole in the center, and prefabricated concrete 3 (1.4.4).

6. The existing concrete frame hybrid structure reinforced with an external self-resetting support frame according to any one of claims 1 to 5, characterized in that: The prefabricated prestressed concrete column (1.1), the prefabricated prestressed hybrid beam (1.2), the self-resetting steel support (1.3), the prefabricated foundation (1.4) and the prefabricated composite panel (2) are all prefabricated components and are manufactured in a standardized manner in a factory; the prefabricated composite panel (2) comprises an outer steel frame with holes (2.1), a sandwich steel plate (2.2) welded inside the outer steel frame (2.1), two cylindrical head welding nails (2.3) welded to the upper and lower surfaces of the sandwich steel plate (2.2) and evenly arranged, a steel mesh (2.4) arranged inside the outer steel frame (2.1), and four prefabricated concrete (2.5) filled inside the outer steel frame (2.1).

7. The existing concrete frame hybrid structure reinforced with an external self-resetting support frame according to claim 3, 4 or 5, characterized in that: The prestressed tendon 1 (1.1.3) and anchor 1 (1.1.5) may adopt a combination of anchor and steel strand with circular clips or a combination of high-quality rolled threaded steel bars and matching nuts according to design requirements; the prestressed tendon 2 (1.2.3) adopts steel strands; anchor 2 (1.2.4) adopts a single-hole circular clip anchor; anchor 3 (1.2.5) adopts a single-hole clip-type low-retraction anchor.

8. The existing concrete frame hybrid structure reinforced with an external self-resetting support frame according to claim 4 or 5, characterized in that: The friction plate 1 (1.2.6) and the friction plate 2 (1.3.7) are made of brass, NAO asbestos-free organic material, ceramic or carbon fiber; the embedded pipe 1 (1.1.1.3), the embedded pipe 2 (1.1.1.4) and the embedded pipe 3 (1.2.2.5) are made of PVC pipe or metal corrugated pipe; the post-implanted anchor bolt (101) is a mechanical anchor bolt or a chemical anchor bolt.

9. The existing concrete frame hybrid structure reinforced with an external self-resetting support frame according to claim 5 is characterized in that: The diameter of the elliptical long holes on the web of the steel section (1.2.2.1.3) and the inner steel plate (1.3.5.1) should ensure that the high-strength bolts 2 (1.2.7) and bolts 4 (1.3.8) have sufficient sliding space under earthquake loads; when pouring precast concrete 3 (1.4.4) of the precast foundation (1.4), appropriate space should be reserved under the square hole of the perforated support plate (1.4.3) to accommodate the placement of anchor 1 (1.1.5).

10. The construction method of reinforcing an existing concrete frame hybrid structure system with an external self-resetting support frame according to claim 1 is characterized in that: Here are the steps: 1) In the factory, the prefabricated prestressed concrete columns (1.1) and prefabricated prestressed hybrid beams (1.2) are manufactured; 2) At the construction site, the outer surface of the frame beam to be connected of the existing concrete frame (3) is cleaned, holes are drilled, and anchor bolts (101) are implanted. A foundation pit is excavated in a predetermined area near the outer side of the existing concrete frame (3), and the prefabricated foundation (1.4) is hoisted and buried after the foundation is strengthened; 3) At the construction site, the prefabricated composite panel (2) is hoisted to the outer side of the frame beam to be connected to the existing concrete frame (3) and the connection between the two is completed by using the post-implanted anchor bolts (101), and the prefabricated prestressed concrete column (1.1) is hoisted to the top of the prefabricated foundation (1.4) and the connection between the two is completed by using the L-shaped anchor bolts (1.4.2) of the foundation; 4) At the construction site, the prefabricated prestressed hybrid beam (1.2) is hoisted to the side of the prefabricated composite panel (2) and bolts 1 (102) and U-shaped bolts (1.2.2.6) are used in sequence to complete the connection with the prefabricated prestressed concrete column (1.1) and the prefabricated composite panel (2); 5) At the construction site, the self-resetting steel support (1.3) is hoisted into the prefabricated frame composed of the prefabricated prestressed concrete column (1.1) and the prefabricated prestressed hybrid beam (1.2) and connected by a pin (103). Then, the high-strength non-shrinkage grouting material (104) is filled in the column top anchoring area of ​​the prefabricated prestressed concrete column (1.1), the reserved through groove of the prefabricated composite board (2) and other gaps. After the strength reaches the standard, the entire process of strengthening the existing concrete frame (3) with the external self-resetting support frame (1) is completed.

Images