A method for underpinning reconstruction of brick masonry walls using UHPC

Abstract

The application discloses a method for underpinning reconstruction of a brick masonry wall by using UHPC, which comprises the following steps: digging filling grooves corresponding to each other on the upper and lower sides of the brick masonry; drilling a plurality of through holes in the brick masonry, which are connected with the filling grooves on the left and right sides of the brick masonry, the through holes are arranged along the length direction of the filling grooves, and the through holes at the upper and lower two groups of filling groove units correspond to each other; placing longitudinal reinforcement along the length direction of the filling grooves, passing a plurality of groups of stirrups through the corresponding two through holes on the upper and lower sides and welding the stirrups into a plurality of closed structures, and the closed structures of the stirrups surround the longitudinal reinforcement; fixing the longitudinal reinforcement and the groups of stirrups at the intersection to form a steel reinforcement cage; installing a formwork on the left and right sides of the brick masonry and leaving grouting holes, and fixing the formwork by using a wooden square and a supporting piece; pouring UHPC from the grouting holes, removing the formwork after the UHPC is coagulated, and removing the wall under the beam. The method is simple, fast and short in construction period, and the structure is high in stability after construction, and the reconstruction and reinforcement effect on the brick masonry is good.

Description

Technical Field

[0001] This invention relates to a wall reinforcement method, and more particularly to a method for replacing and modifying brick masonry walls using UHPC. Background Technology

[0002] Buildings with long service lives are prone to problems with insufficient wall load-bearing capacity, making wall reinforcement particularly important when renovating and reinforcing old buildings. The walls of old buildings are generally made of brick-concrete structure, i.e., brick masonry, and currently, UHPC (Ultra-High-Pressure Polymer) is often used to reinforce these brick-concrete walls.

[0003] In existing technologies, when using UHPC to reinforce brick-concrete structures, it is generally done by adding a reinforcing layer to the outside of the wall. For example, Chinese Patent 2023101440760 discloses a reinforcement structure for masonry and its construction method, in which a reinforcing layer is set on one side of the wall, including a steel plate, angle steel, steel mesh, and a UHPC layer. The steel plate is set on one side of the bottom of the wall, and angle steel is set on the steel plate. The angle steel is connected to the wall, and steel mesh is welded on it. The UHPC layer is poured on the steel plate, angle steel, and steel mesh. However, this reinforcement method is complex to construct, has a long construction period, and the fixing stability of the steel plate and angle steel to the wall is limited.

[0004] In addition, UHPC point reinforcement is also used for strengthening, such as the method disclosed in Chinese Patent 2022111669555, which describes a method for point reinforcement of existing rubble masonry walls using ultra-high performance concrete. This method involves forming point-shaped grooves in the existing rubble masonry wall; setting tie bars between corresponding point-shaped grooves on different sides to form point-shaped UHPCs within the grooves; and setting tie bars between adjacent point-shaped UHPCs on the same side. This reinforcement method connects the UHPC materials on both sides of the wall using steel bars, improving the connection stability between the UHPC and the wall. However, this method only sets UHPCs at points, and the connecting steel bars between each point UHPC are independent, requiring manual installation and a long period of wet curing. The construction is complex and time-consuming, and its applicability to brick-concrete structures is limited. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a method for replacing and modifying brick masonry walls using UHPC that is easy to construct and has high structural stability.

[0006] Technical solution: The present invention provides a method for replacing and modifying brick masonry walls using UHPC, characterized by comprising the following steps:

[0007] (1) Two sets of corresponding filling groove units are excavated on the brick masonry, each set of filling groove units includes two filling grooves symmetrically arranged on both sides of the brick masonry.

[0008] (2) Drill several through holes in the brick masonry to connect the filling grooves on the left and right sides of the brick masonry. The through holes are arranged along the length of the filling grooves, and the through holes at the upper and lower sets of filling groove units correspond to each other.

[0009] (3) Place longitudinal bars along the length of the filling groove, pass several groups of stirrups through the two corresponding through holes above and below and weld them into several closed structures. The closed structures of the stirrups surround the longitudinal bars. Fix the longitudinal bars and each group of stirrups at the intersection to form a steel cage.

[0010] (4) Install templates on both sides of the brick masonry and leave grouting holes. The templates are placed outside the steel cage and fixed with wooden blocks and supports.

[0011] (5) Pour UHPC through the grouting hole until it is completely filled. After the UHPC has solidified, remove the formwork and remove the wall under the beam to complete the replacement.

[0012] Preferably, in step (1), the groove depth of the filling groove on either side is one-quarter of the thickness of the brick masonry.

[0013] Preferably, in step (4), the bottom of both ends of the template is provided with an opening, a steel pad is provided at the opening, and a square steel pipe support is provided at the bottom of the steel pad; the steel pad is part of the template and is fixedly connected to the UHPC support structure after the UHPC is poured.

[0014] Preferably, in step (3), each group of longitudinal bars and stirrups are fixed by binding.

[0015] Preferably, in step (3), each group of stirrups includes two sections of U-shaped steel bars, one of which passes through the through hole and is welded to the other section.

[0016] Preferably, in step (1), the filling groove on the upper part of the brick masonry is opened close to the floor slab, so that the UHPC support structure is fixedly connected to the floor slab.

[0017] Preferably, the template in step (4) is L-shaped, with the top close to the bottom surface of the floor slab and the bottom close to the edge of the filling groove located at the bottom. After placement, it forms an integral cavity structure on one side of the brick masonry. The grouting hole is located on the floor slab, and its opening is located inside the template.

[0018] Preferably, when fixing the template in step (4), horizontal and vertical wooden blocks are set on the outside of the template in sequence, and a horizontal wooden block is set on the outermost side close to the bottom surface of the floor slab. One support is placed between the horizontal wooden block and the ground, and another support is placed between the bottom surface of the template and the ground.

[0019] Preferably, the support member is a telescopic structure.

[0020] Preferably, in step (3), the number of longitudinal ribs at any filling groove is multiple.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: 1. The construction method of the present invention involves the overall excavation of each filling groove and the overall grouting of the UHPC replacement structure, which is simple, quick and has a short construction period; 2. The steel cage is welded into a whole, connecting the UHPC structures on both sides of the wall, and the UHPC structure is in concave-convex fit with the original brick masonry, with the top fixed to the floor slab, resulting in high structural stability after construction and good effect on the modification and reinforcement of the brick masonry. Attached Figure Description

[0022] Figure 1 A structural diagram of a brick masonry wall after the filling groove has been opened;

[0023] Figure 2 A structural diagram of a brick masonry wall after grouting holes and through holes have been made;

[0024] Figure 3 A schematic diagram illustrating the process of setting up the reinforcing cage;

[0025] Figure 4 This is a structural diagram of the brick masonry wall after the formwork has been installed.

[0026] Figure 5 A schematic diagram illustrating the process of reinforcing the formwork and pouring concrete.

[0027] Figure 6 This is a schematic diagram of the UHPC replacement structure after demolding;

[0028] Figure 7 This is a schematic diagram of a reinforcement structure used to strengthen brick masonry.

[0029] Figure 8 A schematic diagram of the structure after the brick masonry was reinforced using the beam replacement method for this project.

[0030] Figure 9 This is a schematic diagram of the modified brick masonry structure according to the present invention;

[0031] Figure 10 for Figure 9 Schematic diagram of AA section;

[0032] Figure 11 for Figure 9 A schematic diagram of the BB cross section. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0034] The method for underpinning and modifying brick masonry walls using UHPC as described in this invention includes the following steps:

[0035] (1) such as Figure 1 As shown, two corresponding filling grooves 3 are chiseled on both sides of the brick masonry 1. The upper filling groove 3 is cut close to the floor slab 2. The groove depth of the filling groove 3 on either side is one-quarter of the thickness of the brick masonry 1.

[0036] (2) such as Figure 2 As shown, grouting holes 5 are drilled in the floor slab, and several through holes 4 are drilled in the brick masonry 1 to connect the filling grooves 3 on the left and right sides. The through holes 4 corresponding to the upper and lower filling grooves 3 are arranged along the length of the filling grooves 3, and the upper and lower corresponding through holes 4 form a group. The through holes 4 can be opened at the mortar joints of the brick masonry 1. The lower through holes 4 can be ground off part of the brick masonry slightly above. The upper through holes 4 are set close to the floor slab 2.

[0037] (3) such as Figure 3 As shown, two sets of longitudinal reinforcement bars 6 are placed along the length of the filling groove 3. Several sets of stirrups 7 are passed through a set of through holes 4 and welded into several closed structures. The closed structures of the stirrups 7 surround the longitudinal reinforcement bars 6 and are at a certain distance from both sides of the brick masonry. Each set of stirrups 7 includes two sections of C-shaped steel bars, one of which is longer and is connected to the other section by welding through two welding points 8 after passing through the through hole 4. The longitudinal reinforcement bars 6 are placed near the side wall of the filling groove 3 and at the corners of the stirrups 7. The longitudinal reinforcement bars 6 and each set of stirrups 7 are fixed at the intersections by binding to form a steel cage. Figure 3 The left side shows the reinforcement bars being laid, and the right side shows the formation of a complete steel cage.

[0038] (4) such as Figure 4 As shown, first support members 9 are installed on both sides of the brick masonry 1. The L-shaped template 10 is placed outside the reinforcing cage, with its top close to the bottom surface of the floor slab 2 and its bottom close to the edge of the filling groove 3 located below. After placement, it forms an integral cavity structure on one side of the brick masonry 1.

[0039] (5) such as Figure 5 As shown, the template is fixed using timber 11 and supporting members. Specifically, the timber 11 includes horizontal, longitudinal, and base timbers arranged outwards in sequence. The horizontal timbers are tightly attached to the outer side of the template 10, and the base timbers are tightly attached to the bottom surface of the floor slab 2. The first supporting member 9 rests between the base timber and the ground, and the second supporting member 12 rests between the bottom surface of the template and the ground. The top of the second supporting member 12 is equipped with a pad structure, and the side of the second supporting member 12 is equipped with a pad timber structure that contacts the longitudinal timber. Both the first supporting member 9 and the second supporting member 12 are telescopic structures, such as hydraulic cylinders, which use their pressure to reinforce the template 10 and the timber 11. The first supporting member 9 at both ends of the beam is replaced with a square steel pipe, and then UHPC13 is poured through the grouting hole 5 until the grouting hole 5 of the floor slab 2 is filled, at which point the filling is complete. Figure 5 The left side shows the reinforcement formwork, and the right side shows the pouring process.

[0040] (6) For example Figure 6 As shown, the reinforcement structure and formwork 10 will be removed after the UHPC support structure has solidified.

[0041] (7) After the UHPC curing strength reaches the standard, the brick masonry 1 under the outer beam of the square steel pipe is removed to complete the replacement and reconstruction. For the end beam structure, the bottom of the steel pad 15 is welded with square steel pipe support 14, and connected to the beam casting by steel bars 16. The lower end of the square steel pipe support 14 is also welded with a steel pad. The two square steel pipes on the same side are connected by welding rods 17. Figure 10 As shown;

[0042] (8) The brick masonry was reinforced using the method of replacing beams with a spur beam. The reinforced structure is as follows: Figure 8 As shown, the structure of the reinforcement is as follows: Figure 7 As shown, the modified brick masonry is as follows: Figure 9 As shown, wall 18 is a wall perpendicular to the beam, and the UHPC support structure is in concave-convex fit with the brick masonry.

[0043] During the construction process of this invention, the spacing between the upper and lower filling grooves 3, the spacing between the template and the brick masonry, the square steel pipe, the steel shim, and the reinforcing bar 16 are determined according to the construction scenario requirements and industry standards, and the specifications and dimensions of the stirrups are determined according to the thickness of the UHPC, so that the reinforcing cage is roughly located in the middle of the UHPC support structure.

[0044] When applying the construction method of this invention, each filling groove is excavated as a whole and the UHPC support structure is grouted as a whole, which is simple, quick and has a short construction period. Moreover, the steel cage is welded into a whole and connects the UHPC structure on both sides of the wall. The UHPC structure fits the original brick masonry with its concave and convex parts, and the top is fixed to the floor slab. After construction, the structure has high stability and a good effect on the transformation and reinforcement of the brick masonry.

Claims

1. A method for underpinning and renovating brick masonry walls using UHPC, characterized in that, Includes the following steps: (1) Two sets of corresponding filling groove units are chiseled on the brick masonry. Each set of filling groove units includes two filling grooves symmetrically arranged on both sides of the brick masonry. The filling groove unit located at the upper part of the brick masonry is opened close to the floor slab. (2) Drill several through holes in the brick masonry to connect the filling grooves on the left and right sides of the brick masonry. The through holes are arranged along the length of the filling grooves, and the through holes at the upper and lower sets of filling groove units correspond to each other. The through holes are opened at the mortar joints of the brick masonry. The lower through holes are ground off part of the brick masonry. The upper through holes are set close to the floor slab. (3) Place longitudinal bars along the length of the filling groove, pass several groups of stirrups through the two corresponding through holes above and below and weld them into several closed structures. The closed structures of the stirrups surround the longitudinal bars. Fix the longitudinal bars and each group of stirrups at the intersection to form a steel cage. (4) Install templates on both sides of the brick masonry and leave grouting holes. The templates are placed outside the steel cage and fixed with wooden blocks and supports. (5) Pour UHPC through the grouting holes until the grouting holes set in the floor slab are filled completely. After the UHPC has solidified, remove the formwork and demolish the wall under the beam to complete the replacement and renovation. In step (3), each stirrup consists of two sections of U-shaped steel bars, one of which passes through a through hole and is welded to the other section. The template mentioned in step (4) is L-shaped, with the top close to the bottom surface of the floor slab and the bottom close to the edge of the filling groove located at the bottom. After placement, it forms an integral cavity structure on one side of the brick masonry. The grouting hole is located on the floor slab, and its opening is located inside the template.

2. The construction method for modifying brick masonry using a UHPC underpinning structure according to claim 1, characterized in that, In step (1), the groove depth of the filling groove is one-quarter of the thickness of the brick masonry.

3. The construction method for modifying brick masonry using a UHPC underpinning structure according to claim 1, characterized in that, In step (4), the bottom of both ends of the template is provided with openings, and steel pads are provided at the openings. Square steel pipe supports are provided at the bottom of the steel pads. After the UHPC is poured, the steel pads are fixedly connected to the UHPC support structure.

4. The construction method for modifying brick masonry using a UHPC underpinning structure according to claim 1, characterized in that, In step (3), the longitudinal bars and stirrups are both fixedly connected by binding.

5. The construction method for modifying brick masonry using a UHPC underpinning structure according to claim 1, characterized in that, When fixing the template in step (4), horizontal and vertical wooden beams are set on the outside of the template in sequence, and horizontal wooden beams are set on the outermost side close to the bottom of the floor slab. One support is placed between the horizontal wooden beam and the ground, and another support is placed between the bottom of the template and the ground.

6. The construction method for modifying brick masonry using a UHPC underpinning structure according to claim 5, characterized in that, The support component is a retractable structure.

7. The construction method for modifying brick masonry using a UHPC underpinning structure according to claim 1, characterized in that, In step (3), there are multiple longitudinal ribs at any filling groove.

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