Ultra-high performance concrete reinforcing structure and method for improving shear resistance of masonry wall

Abstract

The invention provides an ultra-high performance concrete reinforcing structure and method for improving the shear resistance of a masonry wall, and relates to the field of constructions.The ultra-high performance concrete reinforcing structure comprises a brick masonry wall, a reinforcing rib assembly is arranged on one side of the brick masonry wall, and an UHPC surface layer is arranged on one side of the reinforcing rib assembly; a reinforcing mesh is arranged on the reinforcing rib assembly, and a four-corner reinforcing mesh is arranged on one side of the reinforcing mesh. The four-corner reinforcing mesh and the reinforcing mesh are provided with embedded steel bars to be connected with the brick masonry wall, grooves are formed in the connecting positions of the brick masonry wall and the embedded steel bars, and UHPC surface layer materials are arranged at the grooves. By the adoption of the ultra-high performance concrete reinforcing structure for improving the shear resistance of the masonry wall, the bearing capacity, toughness and durability of an existing brick masonry structure can be improved, meanwhile, the carbon emission is reduced, the construction difficulty is reduced, and the construction efficiency and comprehensive economic benefits are improved.

Description

Technical Field

[0001] The invention relates to the field of construction, and in particular to an ultra-high performance concrete reinforcement structure and a method for improving the shear resistance of a masonry wall. Background Art

[0002] Masonry structures are widely distributed in various places at home and abroad due to their advantages such as easy material acquisition and convenient construction. They have a long history and are widely used, such as residential houses, office buildings and factories. These brick masonry structures can reflect the historical features and characteristics of the city and have certain historical, cultural, artistic and scientific values. Under the long-term effects of wind and sun, natural disasters and man-made damage, the brick masonry structure has been severely weathered, the overall stress performance is poor, and local collapse has occurred, which cannot meet its normal use function. Therefore, in order to preserve the original features of historical buildings, historical and cultural buildings have received social attention, and the reinforcement and reuse of historical buildings has become a hot topic.

[0003] At present, the traditional reinforced concrete section enlargement method has many disadvantages. Its reinforcement thickness is large. Since the cross-sectional size is increased after ordinary reinforced concrete reinforcement, the stiffness eccentricity of the reinforced composite section increases greatly. The stiffness eccentricity of the reinforced wall is uncontrollable, which has a great impact on the stress mechanism of the structure under the basic stress state. The ordinary reinforced concrete reinforcement method will significantly increase the structural dead load. The large amount of formwork and reinforcement work leads to a long construction period. The internal frame structure reinforcement method has a longer construction period and requires the foundation to be renovated, which significantly reduces the use space of the original building. The use of existing high-toughness engineering cement-based composite materials for reinforcement is an innovation of the traditional masonry structure reinforcement technology. The strength of high-toughness engineering cement-based composite materials is generally in the range of C40-C50. Due to the high toughness characteristics, thin layer reinforcement can be achieved. However, in the freezing and thawing service environment in severe cold areas, the anti-freeze and thaw durability of materials and reinforcement interfaces needs to be further innovated. In short, the existing related reinforcement technologies and materials still have many limitations in terms of technical and economic aspects.

[0004] Traditional structural reinforcement uses FRP materials, which are resin-based composite materials. They are usually reinforced by bonding sheets. They have the advantages of convenient construction for structural reinforcement, but their fire resistance and anti-aging properties are their main defects. In comparison, UHPC is a cement-based composite material. It is not reinforced by bonding, but by pouring or plastering. It has high strength and durability, and its high temperature resistance is significantly different from that of resin-based composite materials. It is a necessary way to develop high-performance reinforcement. Summary of the invention

[0005] The purpose of the present invention is to provide an ultra-high performance concrete reinforcement structure and method for improving the shear resistance of masonry walls, which can improve the bearing capacity, toughness and durability of existing brick masonry structures, while reducing carbon emissions, reducing construction difficulty, and improving construction efficiency and comprehensive economic benefits.

[0006] To achieve the above object, the present invention provides an ultra-high performance concrete reinforcement structure for improving the shear resistance of a masonry wall, comprising a brick masonry wall, a reinforcing rib assembly is provided on one side of the brick masonry wall, and a UHPC surface layer is provided on one side of the reinforcing rib assembly;

[0007] A steel mesh is arranged on the reinforcing bar assembly, and a four-corner steel mesh is arranged on one side of the steel mesh; embedded steel bars are arranged on the four-corner steel mesh and the steel mesh, and the embedded steel bars are connected to the brick masonry wall, and a groove is arranged at the connection between the brick masonry wall and the embedded steel bars.

[0008] Preferably, the steel mesh is composed of two rectangular steel mesh sheets and is arranged in a V-shape, and the angle between the two steel mesh sheets is in the range of 40° to 60°;

[0009] A first supporting rib is arranged between the two steel meshes; the steel meshes are symmetrically arranged, a distance is arranged between the steel meshes, and a second supporting rib is arranged between the steel meshes.

[0010] Preferably, the four-corner steel mesh includes a first four-corner steel mesh and a second four-corner steel mesh, the first four-corner steel mesh connects the two steel meshes and is located between the two steel meshes, and the second four-corner steel mesh is located at the feet of the steel meshes.

[0011] Preferably, the connection method between the four-corner steel mesh and the steel mesh includes electric welding and bundling;

[0012] The connection methods of the implanted bars and the four-corner steel mesh and the steel mesh include electric welding and bundling.

[0013] Preferably, the brick masonry wall is provided with anchor holes, the anchor bars are located in the anchor holes, and anchor glue is injected into the anchor holes.

[0014] Preferably, the four-corner steel mesh is located between the brick masonry wall and the steel mesh, or the four-corner steel mesh is located on a side away from the brick masonry wall.

[0015] Preferably, the shape of the UHPC surface layer is the same as the shape of the reinforcement rib assembly; the UHPC surface layer strip is arranged on the masonry wall surface along the laying shape of the steel mesh and the four-corner steel mesh, and the width of the UHPC surface layer strip ranges from 100 to 300 mm, and the thickness of the UHPC surface layer strip ranges from 20 to 40 mm.

[0016] Preferably, the arrangement of the embedded bars is along a 45° oblique angle, with additional embedded bars at the four corners of the brick wall; the embedded bar rate is 0.02% to 0.04%, the embedded bar spacing is 200 to 300 mm, the embedded bar depth is 140 to 180 mm, excluding the depth of the groove, and the embedded bar diameter is 6 to 8 mm.

[0017] Preferably, the width of the groove is 100-200 mm, the height of the groove is controlled to be 30-80 mm, and the depth of the groove is controlled to be 20-60 mm.

[0018] A method for strengthening a structure with ultra-high performance concrete to improve the shear resistance of a masonry wall comprises the following steps:

[0019] (1) First, remove impurities and dirt from the surface of the brick masonry wall;

[0020] (2) Mark the location of the embedded reinforcement on the brick wall. The embedded reinforcement is arranged along a 45° oblique angle. Additional embedded reinforcement is arranged at the four corners of the masonry wall. Drill holes to form embedded reinforcement holes, and set grooves at the openings of the embedded reinforcement holes.

[0021] (3) Inject the anchor glue into the groove and the anchor hole, and insert the anchor into the groove and the anchor hole to connect the brick wall and the UHPC surface layer; additionally plant anchors at the weak points at the four corners;

[0022] (4) After 24 hours of time, when the anchor glue has solidified to the designed strength, tie the steel mesh or the four-corner steel mesh to the end of the anchor;

[0023] (5) UHPC120 is used for single-sided pressing along the structure of the reinforcement component.

[0024] Therefore, the present invention adopts the above-mentioned ultra-high performance concrete reinforcement structure and method for improving the shear resistance of masonry walls, and the technical effects are as follows:

[0025] (1) An original method of reinforcing brick masonry walls with cross strips on the surface is proposed. Cross strips of steel bars and UHPC surface are added to the damage surface of the brick masonry wall where shear cracks are most likely to occur, replacing the reinforcement method of the entire wall steel mesh mortar surface layer. The cross strip surface layer bears and disperses the shear stress of the brick masonry wall. The strength grade of UHPC is 120-160MPa. The height-to-width ratio of brick masonry walls is mainly between 0.7 and 1.3. The size of brick masonry walls is not limited. The thickness of the UHPC surface layer, the width of the strips and the strength grade of UHPC can be selected according to the strength grade and usage of the original brick masonry mother wall. The thickness of the UHPC surface layer is controlled at 20-40mm, and the width of the strips is controlled at 100-250mm.

[0026] (2) A certain number of steel bars are arranged in the strips of the UHPC surface layer to form a steel mesh. The angle range of the steel mesh is 40° to 60°. The steel mesh is reliably connected to the original brick masonry wall by single-sided rebar planting or double-sided tensioning to form a common force system. The reinforcement ratio is selected according to the thickness of the reinforced surface layer and the usage. The embedded steel bars are anchored in the brick masonry wall. The diameter of the embedded steel bars is 6 to 10 mm, the length of the anchoring part is controlled at 20 to 40 mm, the bending angle is controlled at 0° to 45°, and the length of the bending part is controlled at 20 to 40 mm. The straight section of the anchoring steel bar and the steel mesh are tied with steel wire ropes before pouring the UHPC surface layer.

[0027] (3) According to the reinforcement position, determine the different single-sided and double-sided reinforcement methods. On the inner surface of the brick masonry wall, in order to protect the surface morphology of the brick masonry wall, the inner single-sided reinforcement method is adopted. In the inner wall, the double-sided reinforcement method is adopted. When the brick masonry wall is long, an "X"-shaped reinforcement method is adopted every 1 to 1.8 m. A reinforcement method is arranged every 1 to 1.8 m in height. A continuous arrangement method is adopted, and the UHPC surface layer between adjacent reinforced brick masonry walls is formed at one time.

[0028] (4) The UHPC used in this application as a surface material has a higher bonding strength than the FRP material. In addition, when used outdoors, ultraviolet radiation will accelerate the aging of the FRP material and reduce its service life. In severe cold conditions, the aging of the FRP material and the bonding strength with the wall will be affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of an ultra-high performance concrete reinforcement structure for improving the shear resistance of a masonry wall according to the present invention;

[0030] Figure 2 This is a front view of an ultra-high performance concrete reinforcement structure for improving the shear resistance of a masonry wall according to the present invention;

[0031] Figure 3 This is a steel mesh arrangement diagram of an ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls according to the present invention;

[0032] Figure 4 A side view of an ultra-high performance concrete reinforcement structure for improving the shear resistance of a masonry wall according to the present invention;

[0033] Figure 5 This is a schematic diagram of an ultra-high performance concrete reinforcement structure for improving the shear resistance of a masonry wall according to the present invention when embedded reinforcement is just inserted.

[0034] Reference numerals

[0035] 1. Brick masonry wall; 2. Reinforcement rib assembly; 21. Steel mesh; 22. Four-corner steel mesh; 221. First four-corner steel mesh; 222. Second four-corner steel mesh; 23. First supporting rib; 24. Second supporting rib; 3. Groove; 4. Embedded reinforcement; 5. UHPC surface layer. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0037] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0038] Embodiment 1

[0039] An ultra-high performance concrete reinforcement structure for improving the shear resistance of a masonry wall comprises a brick masonry wall 1. A reinforcing rib assembly 2 is arranged on one side of the brick masonry wall 1 in an "X" shape. A UHPC surface layer 5 is arranged on one side of the reinforcing rib assembly 2. The UHPC surface layer 5 is also in an "X" shape. The "X"-shaped reinforcement can save space to the maximum extent and ensure that the reinforcement thickness is easy to adjust. At the same time, the reinforcement work can be completed by pressing and troweling.

[0040] By analyzing the stress damage characteristics of the brick masonry wall 1 under the action of earthquakes, targeted reinforcement is carried out at the locations where the "X"-shaped cross-oblique cracks of the brick masonry wall 1 often occur, which can effectively limit the development of the initial cracks of the original brick masonry wall 1, play an effective supporting role, delay the appearance of the main oblique cracks, and thus improve the integrity of the brick masonry wall 1; at the same time, the measures for strengthening the weak points at the four corners also reduce the reinforcement area of ​​the UHPC surface layer 5 and the layout area of ​​the steel mesh 21, effectively reducing the cost and the waste of materials. At the same time, the use of UHPC materials for reinforcement can effectively improve the overall stiffness of the wall surface and improve the comprehensive performance of the reinforced brick masonry wall 1. The schematic diagram of the process of strengthening the existing brick masonry structure by the cross-strip method of the surface layer is shown in the figure. Figure 3 shown.

[0041] A steel mesh 21 is provided on the reinforcement rib assembly 2, and four corner steel meshes 22 are provided on one side of the steel mesh 21; embedded steel bars 4 are provided on the four corner steel meshes 22 and the steel mesh 21, and the embedded steel bars 4 are connected to the brick masonry wall 1, and are reliably connected to the original brick masonry mother wall through single-sided embedded steel bars 4 or double-sided pulling to form a common force system.

[0042] A groove 3 is provided at the connection between the brick masonry wall 1 and the embedded steel bar 4, and a UHPC surface layer 5 material is provided at the groove 3. An embedded steel bar hole is provided on the brick masonry wall 1 at the groove 3, and the embedded steel bar 4 is located in the embedded steel bar hole, and embedded steel bar glue is injected into the embedded steel bar hole.

[0043] The steel mesh 21 is composed of two rectangular steel mesh sheets and is arranged in a V-shape, and the angle between the two steel mesh sheets is in the range of 40° to 60°;

[0044] A first supporting rib 23 is arranged between the two steel meshes; the steel meshes 21 are symmetrically arranged, a distance is arranged between the steel meshes 21, and a second supporting rib 24 is arranged between the steel meshes 21.

[0045] The four-corner steel mesh 22 includes a first four-corner steel mesh 221 and a second four-corner steel mesh 222 . The first four-corner steel mesh 221 connects two steel meshes 21 and is located between the two steel meshes 21 . The second four-corner steel mesh 222 is located at the supporting feet of the steel mesh 21 .

[0046] The connection method of the four-corner steel mesh 22 and the steel mesh 21 includes electric welding, bundling and other methods that can fix the four-corner steel mesh 22 and the steel mesh 21.

[0047] The connection methods of the embedded steel bars 4 and the four-corner steel meshes 22 and 21 include electric welding, bundling and other methods that can fix the embedded steel bars 4 and the four-corner steel meshes 22 and 21.

[0048] The four-corner steel mesh 22 is located between the brick wall 1 and the steel mesh 21. The four-corner steel mesh 22 can also be located on a side away from the brick wall 1. Both position relationships have no effect on the force and are both acceptable.

[0049] The shape of the UHPC surface layer 5 is the same as that of the reinforcing rib assembly 2; the strips of the UHPC surface layer 5 are arranged on the surface of the brick masonry wall 1 along the laying shape of the steel mesh and the four-corner steel mesh, and the strip width ranges from 100 to 300 mm and the thickness ranges from 20 to 40 mm. The strength grade of UHPC is 120 to 160 MPa. The brick masonry wall 1 mainly has a height-to-width ratio between 0.7 and 1.3. The size of the brick masonry wall 1 is not limited. The thickness of the UHPC surface layer 5, the strip width and the strength grade of UHPC can be selected according to the strength grade of the original brick masonry mother wall and the usage.

[0050] The arrangement of the embedded bars 4 is along the 45° oblique angle direction, and embedded bars 4 are additionally arranged at the four corners of the brick masonry wall 1; the embedded bar 4 rate is 0.02% to 0.04%, the spacing of the embedded bars 4 is 200 to 300 mm, the depth of the embedded bars 4 is 140 to 180 mm, excluding the depth of the groove 3, and the diameter of the embedded bars 4 is 6 to 8 mm.

[0051] The width of the groove 3 is 100-200 mm, the height is controlled at 30-80 mm, and the depth is controlled at 20-60 mm.

[0052] The length of the embedded reinforcement 4 buried in the embedded reinforcement hole is controlled to be 20-40 mm, the bending angle is controlled to be, the length of the bent part is controlled to be 20-40 mm, and the straight section of the embedded reinforcement 4 and the steel mesh 21 are tied with steel wire ropes before pouring the UHPC surface layer 5.

[0053] A method for strengthening a structure with ultra-high performance concrete to improve the shear resistance of a masonry wall comprises the following steps:

[0054] (1) First, remove impurities and dirt from the surface of the brick masonry wall 1;

[0055] (2) Mark the position of the embedded reinforcement 4 on the brick masonry wall 1. The arrangement of the embedded reinforcement 4 is along the 45° oblique angle direction. The embedded reinforcement 4 is arranged at the four corners of the brick masonry wall 1. The embedded reinforcement 4 rate is the number of embedded reinforcement 4*the cross-sectional area of ​​the embedded reinforcement 4 / the area of ​​the UHPC surface layer 5. The embedded reinforcement 4 rate is 0.02% to 0.04%. The spacing of the embedded reinforcement 4 is 200 to 300 mm. The depth of the embedded reinforcement 4 is 140 to 180 mm, excluding the depth of the groove 3. The diameter of the embedded reinforcement 4 is 6 to 8 mm. The width of the groove 3 is 100 to 200 mm, the height is controlled at 30 to 80 mm, and the depth is controlled at 20 to 60 mm. Drill holes to form embedded reinforcement holes, and set grooves 3 at the openings of the embedded reinforcement holes.

[0056] (3) Inject the anchor glue into the groove 3 and the anchor hole, and insert the anchor 4 into the groove 3 and the anchor hole to connect the brick masonry wall 1 and the UHPC surface layer 5; additional anchors 4 are planted at the weak points at the four corners;

[0057] (4) After the anchor glue has solidified to the designed strength after a time interval of 24 hours, the steel mesh 21 or the four-corner steel mesh 22 is tied to the end of the anchor 4;

[0058] (5) UHPC120 is used for single-sided pressing along the structure of the reinforcement rib component 2.

[0059] According to the reinforcement position, different single-sided and double-sided reinforcement methods are determined. On the inner surface of the exterior wall, in order to protect the surface morphology of the masonry, the inner single-sided reinforcement method is adopted. In the interior wall, the double-sided reinforcement method is adopted. When the brick masonry wall 1 is long, an "X"-shaped reinforcement method is adopted every 1 to 1.8 m, and a reinforcement method is arranged every 1 to 1.8 m in height. A continuous arrangement method is adopted, and the UHPC plastering between adjacent reinforced brick masonry walls 1 is formed at one time.

[0060] Therefore, the present invention adopts the above-mentioned ultra-high performance concrete reinforcement structure and method for improving the shear resistance of masonry walls. It is a new reinforcement method proposed based on the distribution of shear cracks in brick masonry walls during earthquakes to improve the seismic bearing capacity of masonry structures and improve the ductility of masonry structures. Compared with the existing methods of reinforcement of reinforced steel mesh cement mortar surface layer and reinforced concrete surface layer, this method of reinforcement along the parts of the brick masonry wall where shear stress is concentrated has the advantages of clear force mechanism, improving the bearing capacity of the reinforced brick masonry wall without significantly changing the stiffness of the reinforced brick masonry wall, low construction technology requirements, wide material sources, and economical materials. It can improve the bearing capacity, toughness and durability of existing brick masonry structures, while reducing carbon emissions, reducing construction difficulty, and improving construction efficiency and comprehensive economic benefits.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. An ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls, characterized in that: It comprises a brick masonry wall, one side of which is provided with a reinforcing rib assembly, and one side of which is provided with a UHPC surface layer; A steel mesh is arranged on the reinforcing bar assembly, and a four-corner steel mesh is arranged on one side of the steel mesh; embedded steel bars are arranged on the four-corner steel mesh and the steel mesh, and the embedded steel bars are connected to the brick masonry wall, and a groove is arranged at the connection between the brick masonry wall and the embedded steel bars.

2. The ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls according to claim 1, characterized in that: The steel mesh is composed of two rectangular steel mesh sheets and is arranged in a V shape, and the angle between the two steel mesh sheets is in the range of 40° to 60°; A first supporting rib is arranged between the two steel meshes; the steel meshes are symmetrically arranged, a distance is arranged between the steel meshes, and a second supporting rib is arranged between the steel meshes.

3. The ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls according to claim 1, characterized in that: The four-corner steel mesh includes a first four-corner steel mesh and a second four-corner steel mesh, the first four-corner steel mesh connects the two steel meshes and is located between the two steel meshes, and the second four-corner steel mesh is located at the feet of the steel mesh.

4. The ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls according to claim 1, characterized in that: The connection method between the four-corner steel mesh and the steel mesh includes electric welding and bundling; The connection methods of the implanted bars and the four-corner steel mesh and the steel mesh include electric welding and bundling.

5. The ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls according to claim 1, characterized in that: The brick masonry wall is provided with a reinforcement hole, the reinforcement is located in the reinforcement hole, and reinforcement glue is injected into the reinforcement hole.

6. The ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls according to claim 1, characterized in that: The four-corner steel mesh is located between the brick masonry wall and the steel mesh, or the four-corner steel mesh is located on a side away from the brick masonry wall.

7. The ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls according to claim 1, characterized in that: The shape of the UHPC surface layer is the same as that of the reinforcing rib assembly; the UHPC surface layer strip is arranged on the masonry wall surface along the laying shape of the steel mesh and the four-corner steel mesh, and the width of the UHPC surface layer strip ranges from 100 to 300 mm, and the thickness of the UHPC surface layer strip ranges from 20 to 40 mm.

8. The ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls according to claim 1, characterized in that: The arrangement of the embedded reinforcement is along the 45° oblique angle direction, and embedded reinforcement is additionally arranged at the four corners of the brick masonry wall; the embedded reinforcement rate is 0.02% to 0.04%, the embedded reinforcement spacing is 200 to 300mm, the embedded reinforcement depth is 140 to 180mm, excluding the depth of the groove, and the embedded reinforcement diameter is 6 to 8mm.

9. The ultra-high performance concrete reinforcement structure for improving the shear resistance of masonry walls according to claim 1, characterized in that: The width of the groove is 100-200 mm, the height of the groove is controlled to be 30-80 mm, and the depth of the groove is controlled to be 20-60 mm.

10. A method for strengthening a structure of ultra-high performance concrete for improving the shear resistance of a masonry wall according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) First, remove impurities and dirt from the surface of the brick masonry wall; (2) Mark the location of the embedded reinforcement on the brick wall. The embedded reinforcement is arranged along a 45° oblique angle. Additional embedded reinforcement is arranged at the four corners of the masonry wall. Drill holes to form embedded reinforcement holes, and set grooves at the openings of the embedded reinforcement holes. (3) Inject the anchor glue into the groove and the anchor hole, and insert the anchor into the groove and the anchor hole to connect the brick wall and the UHPC surface layer; additionally plant anchors at the weak points at the four corners; (4) After 24 hours of time, when the anchor glue has solidified to the designed strength, tie the steel mesh or the four-corner steel mesh to the end of the anchor; (5) UHPC120 is used for single-sided pressing along the structure of the reinforcement component.

Images