Connecting joint of steel truss and existing building concrete column and construction method

Abstract

The invention relates to the technical field of building structures, in particular to a steel truss and existing building concrete column connecting joint and a construction method. The connecting joint comprises a bearing support and a truss support. The bearing support comprises a connecting side plate and a support top plate, the connecting side plate is attached to the side face of the concrete column and fixedly connected with the concrete column, and the support top plate is fixedly connected with the connecting side plate and located on the side away from the concrete column; the truss support comprises a connecting bottom plate and an end web member, the connecting bottom plate is installed on a support top plate of the bearing support, the end web member is fixed to the connecting bottom plate, and a truss upper chord and a truss lower chord of the steel truss are fixed to the end web member. The connection node realizes the stable connection of the steel truss and the existing building concrete column at any elevation, and is suitable for the reconstruction and reinforcement engineering of various existing buildings.

Description

Technical Field

[0001] This invention relates to the field of building structure technology, and in particular to a connection node between a steel truss and an existing building concrete column and a construction method thereof. Background Technology

[0002] In industrial park renovation and expansion projects, it is often necessary to use existing buildings as supports to erect cross-road steel trusses to carry integrated pipelines. In this case, the reliable connection between the ends of the steel trusses and the sides of the existing concrete columns becomes crucial.

[0003] Currently, common implementation methods mainly involve pre-embedding connectors in newly constructed concrete structures or adding corbels to existing concrete columns. However, these existing technologies reveal several problems when applied to the renovation of existing buildings: First, their application presupposes that connectors must be pre-designed and embedded during the structural construction phase, making them unsuitable for many existing concrete columns where such pre-embedding is not possible. If post-installation is forcibly adopted, large-scale excavation of concrete to simulate corbels or the installation of large post-anchoring components is often required, resulting in complex construction and significant damage to the original structure. Second, because both the upper and lower chords of the truss need to be fixed to the column, the number of connection points is large, the force transmission path is complex, and the concrete column bears significant additional bending moments and shear forces. Furthermore, this type of connection usually restricts the connection surface to the original width of the concrete column. When connecting two or more trusses to form a spatial truss, the insufficient column width often fails to meet the structural spacing requirements between trusses, resulting in poor adaptability. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a connection node and construction method for steel trusses to existing concrete columns, solving the technical challenge of reliably connecting steel trusses to existing concrete columns without embedded parts or concrete corbels. By providing a connection node that is simple in construction, highly adaptable, and causes minimal damage to the original structure, it enables flexible connections of steel trusses at any elevation of the concrete column, avoids the concrete column bearing the horizontal forces transmitted by the truss, and can accommodate the connection width requirements of spatial trusses.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: A connection node between a steel truss and an existing building concrete column includes: a load-bearing support and a truss support; the load-bearing support includes a connecting side plate and a support top plate, the connecting side plate is attached to the side of the concrete column and fixedly connected to the concrete column, and the support top plate is fixedly connected to the connecting side plate and located on the side away from the concrete column; the truss support includes a connecting bottom plate and an end web member, the connecting bottom plate is installed on the support top plate of the load-bearing support, the end web member is fixed on the connecting bottom plate, and the upper chord and lower chord of the steel truss are fixed on the end web member.

[0006] Optionally, the connecting side plate and the support top plate are perpendicular to each other, the connecting side plate is arranged vertically, and the support top plate is arranged horizontally.

[0007] Optionally, the side of the connecting side plate is attached to the side of the concrete column.

[0008] Optionally, the connecting side plate is anchored to the side of the concrete column by a number of chemical anchors.

[0009] Optionally, the bearing support further includes a first stiffening plate, which is perpendicular to both the connecting side plate and the top plate of the support. The first stiffening plate is located on the bottom side of the top plate of the support, and one end of the first stiffening plate is fixedly connected to the connecting side plate.

[0010] Optionally, the bearing support further includes a second stiffening plate, which is parallel to the connecting side plate and perpendicular to and fixedly connected to the top plate of the support and the first stiffening plate. The second stiffening plate is located directly below the end web member.

[0011] Optionally, the truss support further includes a third stiffening plate, which is fixed to the top surface of the connecting base plate and located around the end web member, with one side of the third stiffening plate being fixedly connected to the lower chord of the truss.

[0012] Optionally, the connecting base plate of the truss support is bolted to the support top plate of the bearing support.

[0013] Optionally, the width of the support top plate of the bearing support is wider than the width of the concrete column, and two steel trusses are installed on the bearing support.

[0014] This invention also provides a construction method for the connection node between a steel truss and an existing building concrete column, comprising the following steps: Grinding is performed on the sides of existing building concrete columns. The connecting side plate of the bearing support is bonded to the side of the polished concrete column using epoxy resin. The connecting side plate is anchored to the concrete column by chemical anchors, and the tightening process of the chemical anchors includes staged tensioning and release operations. Install the connecting base plate of the truss support onto the top plate of the support, so that the upper chord and lower chord of the steel truss are fixed to the end web members respectively. The phased tensioning and release operation of the chemical anchors includes: first, tightening all chemical anchors to the design torque of the first preset ratio and letting them stand for a set time, which is determined according to the initial setting characteristics of the adhesive; then, simultaneously reducing the torque of the chemical anchors to the design torque of the second preset ratio and maintaining a low-pressure state; then, gradually tightening the chemical anchors to the design torque in three stages in a diagonal sequence, maintaining a load state and monitoring deformation after each stage of tightening.

[0015] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: The connection node of this invention mainly includes a load-bearing support and a truss support. The load-bearing support is responsible for connecting to the existing concrete column, including a connecting side plate and a support top plate. The connecting side plate is directly fixed to the side of the concrete column, and the support top plate is fixedly connected to the outside of the connecting side plate. The truss support is responsible for connecting to the steel truss, including a connecting bottom plate and end web members. The connecting bottom plate is installed on the support top plate of the load-bearing support, and the end web members are vertically fixed to the connecting bottom plate. The upper chord and lower chord of the steel truss are ultimately fixed to the end web members. This connection node transforms the connection between the steel truss and the concrete column into a system of independent, post-installed steel structure supports. The load-bearing support can be anchored at any elevation on the side of the column, solving the problem of the original structure lacking embedded parts. All the forces of the truss members are ultimately concentrated and transmitted to the connecting bottom plate through the end web members, and then distributed to the load-bearing support, avoiding the direct transmission of horizontal forces to the concrete column, allowing the concrete column to mainly bear vertical pressure, resulting in a more rational stress distribution. This node system does not rely on embedded parts inside the concrete column, and can achieve a stable connection between the steel truss and the existing building's concrete column at any elevation. It is suitable for renovation and reinforcement projects of various existing buildings.

[0016] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0018] Figure 1 This is a side view of the connection node provided in an embodiment of the present invention; Figure 2 yes Figure 1 Section 2-2; Figure 3 yes Figure 2 Section 3-3; In the diagram: 1. Concrete column; 2. Bearing support; 21. Second stiffening plate; 22. First stiffening plate; 23. Support top plate; 24. Connecting side plate; 25. Chemical anchor; 3. Truss support; 31. Connecting bottom plate; 32. Third stiffening plate; 33. End web member; 4. Truss bottom chord; 5. Truss top chord; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] Example 1 like Figure 1 , Figure 2 , Figure 3 As shown in the figure, this embodiment proposes a connection node between a steel truss and an existing building concrete column 1, including: a load-bearing support 2 and a truss support 3; the load-bearing support 2 includes a connecting side plate 24 and a support top plate 23, the connecting side plate 24 is attached to the side of the concrete column 1 and fixedly connected to the concrete column 1, the support top plate 23 is fixedly connected to the connecting side plate 24 and is located on the side away from the concrete column 1; the truss support 3 includes a connecting bottom plate 31 and an end web member 33, the connecting bottom plate 31 is installed on the support top plate 23 of the load-bearing support 2, the end web member 33 is fixed on the connecting bottom plate 31, and the upper chord 5 and lower chord 4 of the steel truss are fixed on the end web member 33.

[0020] The connecting side plate 24 of the bearing support 2 is attached to and fixed to the side of the concrete column 1, providing a connection foundation for the entire node to the existing building's concrete column 1. The top plate 23 of the support serves as a connecting component, providing an installation carrier for the truss support 3. The connecting bottom plate 31 of the truss support 3 cooperates with the top plate 23 of the support. The end web members 33 support the upper chord 5 and lower chord 4 of the steel truss, forming a complete force transmission path. The upper chord 5 and lower chord 4 of the truss are centrally connected through the end web members 33, reducing the number of connection nodes and simplifying the installation process. At the same time, this structural layout allows the force on the steel truss to be mainly transmitted to the truss support 3 through the end web members 33, and then to the concrete column 1 through the bearing support 2, avoiding the concrete column 1 directly bearing the horizontal force transmitted from the truss chords and optimizing the force system.

[0021] The connecting side plate 24 and the support top plate 23 are perpendicular to each other. The connecting side plate 24 is arranged vertically, and the support top plate 23 is arranged horizontally. The vertical connecting side plate 24 can effectively transfer the vertical pressure from the support top plate 23 to the side of the concrete column 1 through a large-area contact, while the horizontal support top plate 23 provides a stable installation platform for the upper truss support 3.

[0022] The side of the connecting side plate 24 is adhered to the side of the concrete column 1 using epoxy resin adhesive, which is then bonded to the sanded side of the concrete column 1. The epoxy resin adhesive forms a uniform bonding layer between the connecting side plate 24 and the concrete column 1, which can bear part of the load and provide auxiliary fixing for the subsequent drilling and positioning of the chemical anchors 25.

[0023] The connecting side plate 24 is anchored to the side of the concrete column 1 by a number of chemical anchors 25. Under the action of a high-strength chemical adhesive, the bolts are anchored into pre-drilled concrete holes.

[0024] Chemical anchors 25 can withstand significant tensile and shear forces, and are particularly effective at transferring bending moments generated by steel truss loads. The combination of epoxy resin bonding and chemical anchor 25 anchoring—the former providing surface adhesion and stress distribution, and the latter providing deep anchoring and critical force transfer—works synergistically to enhance the overall reliability and load-bearing capacity of the connection joint, making it especially suitable for the reinforcement and renovation of existing structures.

[0025] The bearing support 2 also includes a first stiffening plate 22, which is perpendicular to both the connecting side plate 24 and the top plate of the support. The first stiffening plate 22 is located on the bottom side of the top plate of the support, and one end of the first stiffening plate 22 is fixedly connected to the connecting side plate 24.

[0026] The first stiffening plate 22 enhances the rigidity and stability of the bearing support 2 itself. When the top plate 23 of the support is subjected to vertical pressure from the upper truss support 3, the first stiffening plate 22 can effectively prevent the top plate 23 of the support from undergoing excessive bending deformation and transfer part of the load to the connecting side plate 24, thereby optimizing the stress distribution inside the bearing support 2 and improving the overall rigidity and local bearing capacity of the node.

[0027] The bearing support 2 also includes a second stiffening plate 21, which is parallel to the connecting side plate 24 and is perpendicular to and fixedly connected to the support top plate 23 and the first stiffening plate 22. The second stiffening plate 21 is located directly below the end web member 33.

[0028] The second stiffening plate 21, together with the first stiffening plate 22 and the support top plate 23, constitutes a local three-dimensional stiffening system, which enhances the bending and shear resistance of the support top plate 23 in the area of ​​the action point of the end web member 33, prevents local buckling or excessive deformation in this area under concentrated load, and ensures that the load can be transferred downward smoothly and reliably.

[0029] The truss support 3 also includes a third stiffening plate 32, which is fixed to the top surface of the connecting base plate 31 and located on the periphery of the end web member 33. One side of the third stiffening plate 32 is fixedly connected to the lower chord 4 of the truss.

[0030] The surrounding third stiffening plate 32 effectively provides stiffening ribs at the root of the end web member 33, enhancing the rigidity and fatigue resistance of the welded joint between the end web member 33 and the connecting base plate 31. One side of the third stiffening plate 32 is fixed to the lower chord 4 of the truss, enabling it to directly transfer a portion of the horizontal force of the lower chord 4 to the connecting base plate 31 and the entire support system. This optimizes the stress state of the joint, distributes the load of the end web member 33, and improves the overall integrity and safety of the joint.

[0031] The connecting base plate 31 of the truss support 3 is bolted to the support top plate 23 of the bearing support 2.

[0032] Bolted connections offer disassembly and adjustability. This connection method facilitates alignment and fine-tuning during on-site installation, allowing for precise control of the truss's elevation and position during installation. Simultaneously, bolted connections also facilitate future maintenance or disassembly, offering greater construction flexibility and adaptability compared to fully welded connections.

[0033] The width of the support top plate 23 of the bearing support 2 is wider than the width of the concrete column 1. The installation of two steel trusses on the bearing support 2 solves the problems that a single concrete column 1 can only connect to a single truss, and cannot connect to a spatial truss, as well as the issue that the width of the existing concrete column 1 cannot meet the connection requirements of the spatial steel truss. By widening the support top plate 23, a cantilevered, wider platform is created on the side of the column. This platform can accommodate the end supports of the two parallel trusses, allowing them to maintain sufficient structural spacing, thus achieving the goal of supporting a spatial steel truss system using a single existing concrete column 1, and expanding the applicability and function of this connection node.

[0034] In summary, the steel bearing support 2 provides vertical support for the original column without concrete corbels. It only extends the vertical end web members 33 to extend the lower chord and connects them to the steel support. The number of connection nodes between the steel truss and the original structure is small. In terms of force, the concrete column 1 does not need to bear the horizontal force transmitted from the steel truss, and the connection width of the original concrete column 1 can be widened within a certain range to facilitate the installation of the space truss.

[0035] This connection node enables the steel truss to be connected to the existing building's concrete column 1 at any elevation, solving the problems of the existing building's concrete column 1 lacking embedded steel plates and vertical supports, and failing to meet the structural spacing requirements of the two trusses; it is simple to manufacture and easy to install.

[0036] Example 2 This embodiment provides a construction method for the connection node between a steel truss and an existing building concrete column 1, including the following steps: The side surface of the existing concrete column 1 was ground. The connecting side plate 24 of the bearing support 2 is attached to the side of the polished concrete column 1 with epoxy resin. The connecting side plate 24 is anchored to the concrete column 1 by chemical anchors 25, wherein the tightening process of the chemical anchors 25 includes staged tensioning and release operations. Install the connecting base plate 31 of the truss support 3 on the support top plate 23, so that the upper chord 5 and the lower chord 4 of the steel truss are fixed on the end web members 33 respectively. If chemical anchors are tightened to the design torque in one go, the adhesive is prone to uneven distribution under pressure, resulting in air bubbles or weak areas at the interface. This leads to large dispersion in the anchor's bearing capacity, poor performance of group anchors working together, and affects the long-term safety of the node.

[0037] Based on this, the phased tensioning and release operation of the chemical anchors 25 includes: first, tightening all chemical anchors 25 to the design torque of the first preset ratio and letting them stand, with the standing time determined according to the initial setting characteristics of the adhesive; then, simultaneously reducing the torque of the chemical anchors 25 to the design torque of the second preset ratio and maintaining a low-pressure state; then, gradually tightening the chemical anchors 25 to the design torque in three stages in a diagonal sequence, maintaining a load state and monitoring deformation after each stage of tightening.

[0038] This phased construction method improves the quality and reliability of chemical anchor bolt 25 anchoring. Initial low-pressure penetration and stress release ensure the uniformity and density of the colloid filling within the hole. Subsequent staged diagonal tightening guarantees synchronized force distribution and good synergistic performance among the anchor groups. This method reduces anchoring force dispersion, enhances the overall bearing capacity and long-term durability of individual anchor bolts and anchor groups, and guarantees the final safety of the connection nodes from a construction process perspective.

[0039] Specifically, the following steps are included: Step 1: Initial Tightening and Setting. Using a linked-control electric torque wrench, tighten all chemical anchors 25 to 30% of the designed final torque value, and then leave them in this position to set. The setting time depends on the initial setting time of the adhesive product used, and is typically 30 minutes to 2 hours, allowing the adhesive to initially form under low pressure and produce slight penetration.

[0040] The second step is unloading and low-pressure penetration. After initial setting and settling, the torque of all chemical anchors 25 is simultaneously unloaded to 10% of the design torque and maintained at this low pressure for 10 to 15 minutes. This decompression process releases initial stress and creates conditions for the colloid to further penetrate into the microcracks of the concrete under low pressure, which is beneficial for the removal of microbubbles.

[0041] The third step is graded final tightening and monitoring. All anchor bolts are tightened in three stages, following a diagonal sequence, with torques of 60%, 80%, and 100% of the design torque, respectively. Each stage of torque loading is held for 5 minutes. During this holding period, deformation of the support top plate 23 of the bearing support 2 is monitored. For example, a displacement sensor is installed at the center of the outer edge of the support top plate 23 to measure its vertical displacement. If the displacement continues to increase beyond a preset threshold during any stage of holding, the process is paused and inspected.

[0042] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A connection node between a steel truss and an existing building's concrete column, characterized in that, include: Load-bearing supports and truss supports; The bearing support includes a connecting side plate and a support top plate. The connecting side plate is attached to the side of the concrete column and fixedly connected to the concrete column. The support top plate is fixedly connected to the connecting side plate and is located on the side away from the concrete column. The truss support includes a connecting base plate and end web members. The connecting base plate is installed on the support top plate of the bearing support, and the end web members are fixed on the connecting base plate. The upper chord and lower chord of the steel truss are fixed on the end web members.

2. The connection node between the steel truss and the existing building concrete column as described in claim 1, characterized in that, The connecting side plate and the support top plate are perpendicular to each other, the connecting side plate is arranged vertically, and the support top plate is arranged horizontally.

3. The connection node between the steel truss and the existing building concrete column as described in claim 1, characterized in that, The side of the connecting side plate is attached to the side of the concrete column.

4. The connection node between the steel truss and the existing building concrete column as described in claim 3, characterized in that, The connecting side plate is anchored to the side of the concrete column by a number of chemical anchors.

5. The connection node between the steel truss and the existing building concrete column as described in claim 2, characterized in that, The bearing support also includes a first stiffening plate, which is perpendicular to both the connecting side plate and the top plate of the support. The first stiffening plate is located on the bottom side of the top plate of the support, and one end of the first stiffening plate is fixedly connected to the connecting side plate.

6. The connection node between the steel truss and the existing building concrete column as described in claim 5, characterized in that, The bearing support also includes a second stiffening plate, which is parallel to the connecting side plate and is perpendicular to and fixedly connected to the top plate of the support and the first stiffening plate. The second stiffening plate is located directly below the end web member.

7. The connection node between the steel truss and the existing building concrete column as described in claim 1, characterized in that, The truss support also includes a third stiffening plate, which is fixed to the top surface of the connecting base plate and located around the end web member. One side of the third stiffening plate is fixedly connected to the lower chord of the truss.

8. The connection node between the steel truss and the existing building concrete column as described in claim 1, characterized in that, The connecting base plate of the truss support is bolted to the support top plate of the bearing support.

9. The connection node between the steel truss and the existing building concrete column as described in claim 1, characterized in that, The width of the top plate of the bearing support is wider than the width of the concrete column, and two steel trusses are installed on the bearing support.

10. A construction method for a connection node between a steel truss and an existing building's concrete column, characterized in that, Includes the following steps: Grinding is performed on the sides of existing building concrete columns. The connecting side plate of the bearing support is bonded to the side of the polished concrete column using epoxy resin. The connecting side plate is anchored to the concrete column by chemical anchors, and the tightening process of the chemical anchors includes staged tensioning and release operations. Install the connecting base plate of the truss support onto the top plate of the support, so that the upper chord and lower chord of the steel truss are fixed to the end web members respectively. The phased tensioning and release operation of the chemical anchors includes: first, tightening all chemical anchors to the design torque of the first preset ratio and letting them stand for a set time, which is determined according to the initial setting characteristics of the adhesive; then, simultaneously reducing the torque of the chemical anchors to the design torque of the second preset ratio and maintaining a low-pressure state; then, gradually tightening the chemical anchors to the design torque in three stages in a diagonal sequence, maintaining a load state and monitoring deformation after each stage of tightening.

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