A new corbel system with difficult-to-damage connecting position and construction method thereof

Abstract

The present application relates to the technical field of connecting technology of general building structure, and discloses a new added corbel system with a connecting position not easy to be damaged and a construction method thereof, which comprises a steel corbel arranged on the side of an existing column, the steel corbel extends to the existing column on the left and right sides and forms a column embracing plate which clamps the existing column and is fixedly connected with the existing column; after the construction is completed, the load on the steel corbel is recorded as a new added load, and an additional steel column with a pre-applied axial force equal to the new added load is arranged below the joint position of the steel corbel and the existing column. In the present application, the joint position of the existing column and the steel corbel is supported by the additional steel column with the pre-applied axial force equal to the new added load, so that the existing column does not bear the new added load, the horizontal tensile force applied on the top of the corbel and the horizontal compressive force applied on the bottom of the corbel, thereby ensuring that the existing column will not be damaged due to the load exceeding the bearing capacity, and the connecting position between the existing column and the steel corbel will not be damaged by the tensile force and the compressive force.

Description

Technical Field

[0001] This invention relates to the field of connection technology for general building structures, and in particular to a new corbel system and its construction method that is not easily damaged at the connection position. Background Technology

[0002] A corbel, also known as a beam support, is usually placed on the side of a column to support the end of a beam.

[0003] The connection between the corbel and the column is highly susceptible to damage. Although the corbel exerts downward pressure on the column as a whole, the force transmission at the connection point is quite complex. The junction between the column and the upper surface of the corbel bears horizontal tensile force, while the junction between the column and the lower surface of the corbel bears horizontal compressive force. At the same time, the end of the corbel near the column bears shear force. Although these forces are not large, the area of ​​stress distribution is small, and they involve some structural weaknesses (such as the low tensile strength of concrete, making concrete columns easily damaged under tension). Therefore, the connection point is prone to damage.

[0004] The damage process at the connection point between the steel bracket and the concrete column (including reinforced concrete column) is as follows:

[0005] When the connection between the corbel and the column is damaged, a vertical crack first appears at the junction of the column and the upper surface of the corbel, but it develops slowly. Then, a downward-developing diagonal crack appears on the inner side of the loading plate. Subsequently, the crack continues to expand, and a large number of small cracks appear on the outer side of the loading plate. Finally, a crack suddenly appears under the pad, and the connection fails.

[0006] As for steel columns, they will not crack and have high tensile strength. Damage to the connection between the steel bracket and the steel column usually manifests as instability of the steel bracket, specifically as the bottom of the steel bracket is gradually deformed by pressure.

[0007] Because the connection between the corbel and the column is prone to damage, finite element software is usually used to analyze the stress condition of the connection before construction, and the drawings are refined based on the analysis results to ensure that the connection can safely bear the stress.

[0008] However, the above operations are only applicable to the scenario where the corbel and column are constructed together. If the corbel is installed on an existing column (this construction scenario is not uncommon, such as adding some beams to the existing column), then the above methods cannot be used, because the column design cannot be changed. The newly added corbel and the load on the corbel may exceed the bearing capacity of the existing column. Even if the bearing capacity of the existing column is sufficient, the connection position has not been verified to withstand the complex local stress conditions, and it may still be damaged. Summary of the Invention

[0009] This invention provides a new bracket system with connection points that are not easily damaged, and its construction method.

[0010] The technical problem to be solved is that when installing steel brackets on existing columns to support new components, it may exceed the load-bearing capacity of the existing columns, and the connection points are prone to damage.

[0011] To solve the above technical problems, the present invention adopts the following technical solution: a new bracket system with a connection position that is not easily damaged, comprising a steel bracket set on the side of an existing column, wherein the steel bracket extends toward the existing column on both the left and right sides and forms a column clamping plate that clamps the existing column, and the column clamping plate is fixedly connected to the existing column.

[0012] After construction is completed, the load on the steel bracket is recorded as the new load. An additional steel column is installed below the junction of the steel bracket and the existing column to prevent the new load from damaging the existing column.

[0013] Furthermore, the additional steel column is a prestressed steel column, which carries a prestressed axial force equal to the new load, and the additional steel column is fixedly connected to the existing column at multiple positions along its length.

[0014] Furthermore, the existing column is a stone column, a concrete column, or a reinforced concrete column, and the load on the existing column is not less than the newly added load. The column retaining plate and the additional steel column are fixedly connected to the existing column by anchor bolts, and the bottom of the additional steel column is anchored to the foundation.

[0015] Furthermore, the existing column is a column with a rectangular cross-section, and the side of the existing column that is attached to the additional steel column is called the installation facade. The additional steel column is a steel pipe column with a rectangular cross-section, and the length of the long side of the rectangle is equal to the width of the installation facade.

[0016] Furthermore, the steel bracket is a variable cross-section steel pipe that extends horizontally outward from one end of the existing column. The variable cross-section steel pipe is formed by a horizontally set top plate, two vertically set side plates that are flush with the column retaining plate and integrally formed, and a bottom plate that extends horizontally outward from the existing column and extends obliquely upward after passing the additional steel column.

[0017] Furthermore, the steel bracket is provided with multiple stiffening baffles parallel to the installation facade at intervals, and two stiffening baffles are aligned vertically with and welded to the two side wall panels of the additional steel column that are parallel to the installation facade; the steel bracket is also provided with a central baffle perpendicular to the installation facade and the ground, and the central baffle is welded to each stiffening baffle and the existing column as a whole.

[0018] A construction method for a new bracket system with connection points that are not easily damaged, used for constructing the aforementioned new bracket system with connection points that are not easily damaged, includes the following steps:

[0019] Step 1: Drill anchor bolt holes corresponding to the anchor bolts on the column retaining plate and the additional steel column to avoid danger when drilling holes in the additional steel column after it has been prestressed. The top and bottom of the anchor bolt holes should fit the anchor bolts.

[0020] Step 2: Connect the steel brackets, column cladding, and additional steel columns into a single unit, and remember the bracket system;

[0021] Step 3: Hoist the corbel system so that the additional steel column and column clamping plate hold the existing column, and then fix the lower end of the additional steel column to the foundation;

[0022] Step 4: Apply pressure along the axial direction to the additional steel column so that the additional steel column carries the pre-applied axial force;

[0023] Step 5: Secure the column clamping plate and additional steel column to the existing column using anchor bolts, and then remove the equipment that applies pressure to the additional steel column;

[0024] Step Six: Install the load-bearing components onto the steel bracket.

[0025] Furthermore, in step four, a cable is used to apply pressure to the additional steel column. The steel bracket is located above the additional steel column and has a rope-threading ear plate aligned with the top and bottom of the middle partition. The cable is threaded through the rope-threading ear plate and has tensioning devices at both ends. The resultant force of the two tensioning devices on the cable is downward and equal to the newly applied load.

[0026] Furthermore, in step four, before pressurization, the two column clamping plates are connected as one unit using anti-tilting buckles. The anti-tilting buckles are set on the side of the existing column away from the installation facade. The anti-tilting buckles are steel plates bent into right-angled U-shapes. The inner side of the right-angled U-shape is respectively attached to the column clamping plate and the existing column, and is connected to the column clamping plate by bolts.

[0027] Furthermore, the anchor bolt is a rear-expanded anchor bolt, and the anchor bolt hole is a waist hole with the long axis set horizontally.

[0028] Compared with the prior art, the new bracket system and its construction method, which are less prone to damage at the connection points, have the following advantages:

[0029] In this invention, by using an additional steel column with a pre-applied axial force equal to the new load to support the junction between the existing column and the steel bracket, the existing column is not subjected to the new load, nor to the horizontal tensile force applied to the top of the bracket or the horizontal compressive force applied to the bottom of the bracket (note that without the pre-applied axial force, the additional steel column will be compressed after being compressed, which will still cause the new load, tensile force, and compressive force to be transmitted to the existing column). This ensures that the existing column will not be damaged due to the load exceeding its bearing capacity, and the connection between the existing column and the steel bracket will not be damaged by tensile force and compressive force. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a new bracket system in the present invention, where the connection position is not easily damaged;

[0031] Figure 2 for Figure 1 Cross-sectional view of section AA;

[0032] Figure 3 This is a schematic diagram illustrating the application of pressure to the additional steel column.

[0033] Figure 4 for Figure 3 Cross-sectional view of section BB in the middle;

[0034] In the diagram, 1-existing column, 2-steel bracket, 21-rope threading plate, 22-stiffening partition, 23-middle partition, 3-column clamping plate, 4-additional steel column, 5-cable, 6-anti-tilting buckle plate. Detailed Implementation

[0035] like Figure 1-2 As shown, a new bracket system with a connection position that is not easily damaged includes a steel bracket 2 set on the side of the existing column 1. The steel bracket 2 extends to the existing column 1 on the left and right sides and forms a column clamping plate 3 that clamps the existing column 1. The column clamping plate 3 is fixedly connected to the existing column 1.

[0036] After construction, the load on the steel bracket 2 is recorded as the new load. An additional steel column 4 is installed below the junction of the steel bracket 2 and the existing column 1 to prevent the new load from damaging the existing column 1. Note that all loads in this article refer to force, not force divided by area (i.e., surface load).

[0037] The steel bracket 2 here is not directly connected to the existing column 1. Instead, the new load is stably transferred to the foundation through a combination of two methods: the column retaining plate 3 restricts the displacement of the steel bracket 2 in the horizontal plane, while the additional steel column 4 transfers the new load to the foundation. The additional steel column 4 is chosen as a steel column for quick installation. The additional steel column 4 is directly connected to the existing column 1, so there is no need to consider instability under horizontal forces, and therefore the cross-sectional area can be very small.

[0038] The additional steel column 4 is a prestressed steel column, which carries a pre-applied axial force equal to the applied load. The additional steel column 4 is fixedly connected to the existing column 1 at multiple locations along its length. The multiple connections serve two purposes: first, to effectively prevent the additional steel column 4 from becoming unstable; and second, to ensure that after the equipment applying pressure to the additional steel column 4 is removed, the rebound of the additional steel column 4 can be evenly suppressed at multiple locations.

[0039] The reason for using prestressed steel columns here is to ensure that the additional steel column 4 will not be compressed after the new load is applied to the steel bracket 2. This is because the components supported by the steel bracket 2, such as new steel beams, need to be installed after the steel bracket 2 is installed. During the installation of these components, the column clamping plate 3 and the additional steel column 4 are already fixed to the existing column 1 (if not fixed, the additional steel column 4 is easily tilted or unstable due to horizontal forces when the new steel beam is installed; however, the prestressed axial force will not exert horizontal forces on the additional steel column 4, so this problem does not exist). At this point, when the new steel beam is installed, the new load is transferred to the existing column 1, and the existing column 1 will also bear tensile and compressive forces at the connection point. Of course, if there is a simple method (complex methods exist, such as using a thick-walled steel cylinder composed of two semi-cylinders to enclose the additional steel column 4, with diagonal bracing around the circumference of the steel cylinder) to ensure that the additional steel column 4 will not tilt or become unstable during the installation of the new steel beam, then prestressed steel columns can be omitted.

[0040] The existing column 1 is a stone column, concrete column or reinforced concrete column. The load on the existing column 1 is not less than the newly added load. The column retaining plate 3 and the additional steel column 4 are fixedly connected to the existing column 1 by anchor bolts, and the bottom of the additional steel column 4 is anchored to the foundation.

[0041] The load on existing column 1 must not be less than the newly applied load to ensure that, after step five, existing column 1 will not be subjected to tensile forces. This is because after the equipment applying pressure to the additional steel column 4 is removed, the upward reaction force of the additional steel column 4 is applied to existing column 1, and the magnitude of the reaction force is equal to the newly applied load. If the newly applied load is greater than the load on existing column 1, existing column 1 will be subjected to upward tensile forces. Stone columns, concrete columns, or reinforced concrete columns have extremely low tensile strength, making them easily damaged in this situation.

[0042] The existing column 1 is a column with a rectangular cross-section. The side of the existing column 1 that is attached to the additional steel column 4 is called the installation facade. The additional steel column 4 is a steel pipe column with a rectangular cross-section, and the length of the long side of the rectangle is equal to the width of the installation facade. In this way, the additional steel column 4 has little impact on the shape of the existing column 1.

[0043] The steel bracket 2 is a variable cross-section steel pipe extending horizontally outward from the existing column 1. The variable cross-section steel pipe is formed by a horizontally arranged top plate, two vertically arranged side plates that are flush with the column retaining plate 3 and integrally formed, and a bottom plate that extends horizontally outward from the existing column 1 and then obliquely upward after passing the additional steel column 4. This structure can increase the contact area between the steel bracket 2 and the existing column 1, and the top is flat, which facilitates the application of preloaded axial force.

[0044] The steel bracket 2 is equipped with multiple stiffening baffles 22 parallel to the installation facade at intervals. Two stiffening baffles 22 are aligned vertically with and welded to the two side wall panels of the additional steel column 4, which are parallel to the installation facade. The steel bracket 2 also has a central baffle 23 perpendicular to the installation facade and the ground. The central baffle 23 is welded to each stiffening baffle 22 and the existing column 1 as a whole. This is to facilitate the application of pre-loaded axial force at the top of the steel bracket 2 using cables 5. The stiffening baffles 22 and the central baffle 23 not only increase the rigidity of the steel bracket 2, but also facilitate the direct transmission of pressure from the top to the additional steel column 4 along the central baffle 23.

[0045] A construction method for a new bracket system with connection points that are not easily damaged, used for constructing the aforementioned new bracket system with connection points that are not easily damaged, includes the following steps:

[0046] Step 1: Make anchor bolt holes corresponding to the anchor bolts on the column-supporting plate 3 and the additional steel column 4 to avoid danger when drilling holes on the additional steel column 4 after it has been prestressed. The top and bottom of the anchor bolt holes should fit the anchor bolts.

[0047] Step 2: Connect the steel bracket 2, column retaining plate 3, and additional steel column 4 into a whole, and remember the bracket system;

[0048] Step 3: Hoist the bracket system so that the additional steel column 4 and the column clamping plate 3 can hold the existing column 1, and then fix the lower end of the additional steel column 4 to the foundation;

[0049] Step 4: Apply pressure to the additional steel column 4 along the axial direction so that the additional steel column 4 carries the pre-applied axial force;

[0050] Step 5: Secure the column clamping plate 3 and the additional steel column 4 to the existing column 1 with anchor bolts, and then remove the equipment that applied pressure to the additional steel column 4; since the additional steel column 4 has been secured to the existing column 1 with anchor bolts, it will not spring back and the pre-applied axial force will be released.

[0051] Step 6: Install the components to be supported on the steel bracket 2.

[0052] like Figure 3-4 As shown, in step four, a cable 5 is used to apply pressure to the additional steel column 4. A rope-threading lug 21, aligned vertically with the central diaphragm 23, is welded to the steel bracket 2 above the additional steel column 4. The cable 5 is threaded through the rope-threading lug 21 and has tensioning devices at both ends. The resultant force exerted by the two tensioning devices on the cable 5 is downward and equal in magnitude to the newly applied load. Prestressed steel cables are preferable for the cable 5 used here.

[0053] The tensioning equipment here can be the commercially available prestressed cable tensioning equipment; there is no need for special research and development.

[0054] Step four: Before applying pressure, connect the two column retaining plates 3 together using anti-tilting buckle plates 6. The anti-tilting buckle plates 6 are installed on the side of the existing column 1 facing away from the installation facade. The anti-tilting buckle plates 6 are steel plates bent into a right-angled U-shape, with the inner sides of the right-angled U-shape abutting against both the column retaining plate 3 and the existing column 1, and connected to the column retaining plate 3 with bolts. After construction, the anti-tilting buckle plates 6 can be removed for reuse, or left in place to enhance the stability of the connection. In this embodiment, the option of removal for reuse is chosen.

[0055] The anchor bolts are post-expanded anchor bolts, which have high pull-out resistance and are very stable. The anchor bolt holes are horizontally arranged waist holes to facilitate post-expansion.

[0056] The steel bracket 2, the column retaining plate 3, and the anti-tilting buckle plate 6 are all coated with paraffin wax. This ensures that the load will not be transferred to the existing column 1 when the additional steel column 4 is compressed in step four.

[0057] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A new bracket system with a connection position that is not easily damaged, comprising a steel bracket (2) disposed on the side of an existing column (1), characterized in that: The steel bracket (2) extends to the existing column (1) on both sides and forms a column clamping plate (3) that clamps the existing column (1). The column clamping plate (3) is fixedly connected to the existing column (1). After the construction is completed, the load on the steel bracket (2) is recorded as the new load. An additional steel column (4) is set below the junction of the steel bracket (2) and the existing column (1) to prevent the new load from damaging the existing column (1). The additional steel column (4) is a prestressed steel column, which has a prestressed axial force equal to the new load. The additional steel column (4) is fixedly connected to the existing column (1) at multiple positions along its length. The existing column (1) is a stone column, concrete column or reinforced concrete column. The load on the existing column (1) is not less than the newly added load. The column retaining plate (3) and the additional steel column (4) are fixedly connected to the existing column (1) by anchor bolts, and the bottom of the additional steel column (4) is anchored to the foundation.

2. The new bracket system with a connection position that is not easily damaged according to claim 1, characterized in that: The existing column (1) is a column with a rectangular cross-section. The side of the existing column (1) that is attached to the additional steel column (4) is called the installation surface. The additional steel column (4) is a steel pipe column with a rectangular cross-section, and the length of the long side of the rectangle is equal to the width of the installation surface.

3. The new bracket system with a connection position that is not easily damaged according to claim 2, characterized in that: The steel bracket (2) is a variable cross-section steel pipe that extends horizontally outward from the existing column (1). The variable cross-section steel pipe is formed by a horizontally set top plate, two vertically set side plates that are flush with the column plate (3) and integrally formed, and a bottom plate that extends horizontally outward from the existing column (1) and extends obliquely upward after passing the additional steel column (4).

4. The new bracket system with a connection position that is not easily damaged according to claim 3, characterized in that: The steel bracket (2) is provided with multiple stiffening baffles (22) parallel to the installation facade at intervals. Two stiffening baffles (22) are aligned with the two side wall panels of the additional steel column (4) parallel to the installation facade and welded together. The steel bracket (2) is also provided with a middle baffle (23) perpendicular to the installation facade and the ground. The middle baffle (23) is welded together with each stiffening baffle (22) and the existing column (1).

5. A construction method for a new bracket system with connections that are not easily damaged, characterized in that: For construction of a new bracket system with a connection position that is not easily damaged as described in claim 4, the following steps are included: Step 1: Make anchor bolt holes corresponding to the anchor bolts on the column plate (3) and the additional steel column (4) to avoid danger when drilling holes on the additional steel column (4) after it has prestressed. The top and bottom of the anchor bolt holes are in contact with the anchor bolts. Step 2: Connect the steel bracket (2), the column plate (3), and the additional steel column (4) into a whole, and remember the bracket system; Step 3: Hoist the corbel system so that the additional steel column (4) and the column clamping plate (3) clamp the existing column (1), and then fix the lower end of the additional steel column (4) to the foundation; Step 4: Apply pressure to the additional steel column (4) along the axial direction so that the additional steel column (4) carries the pre-applied axial force; Step 5: Secure the column-mounted plate (3) and the additional steel column (4) to the existing column (1) with anchor bolts, and then remove the equipment that applied pressure to the additional steel column (4); Step 6: Install the components to be supported on the steel bracket (2).

6. The construction method of a newly added bracket system with a connection position that is not easily damaged according to claim 5, characterized in that: In step four, a cable (5) is used to apply pressure to the additional steel column (4). The steel bracket (2) is located above the additional steel column (4) and has a rope-threading ear plate (21) aligned vertically with the middle partition plate (23). The cable (5) is threaded through the rope-threading ear plate (21) and has tensioning devices at both ends. The resultant force of the two tensioning devices on the cable (5) is downward and equal to the newly added load.

7. The construction method of a newly added bracket system with a connection position that is not easily damaged according to claim 5, characterized in that: Step 4 Before pressurization, the two column clamping plates (3) are connected as one unit using the anti-tilting buckle plate (6). The anti-tilting buckle plate (6) is set on the side of the existing column (1) away from the installation facade. The anti-tilting buckle plate (6) is a steel plate bent into a right-angled U-shape. The inner side of the right-angled U-shape is respectively attached to the column clamping plate (3) and the existing column (1) and is connected to the column clamping plate (3) by bolts.

8. The construction method of a newly added bracket system with a connection position that is not easily damaged according to claim 5, characterized in that: The anchor bolt is a rear-expanded bottom anchor bolt, and the anchor bolt hole is a waist hole with the long axis set horizontally.

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