A composite tie beam structure for widening a bridge and its construction and calculation method

Abstract

The present invention discloses a composite tie beam structure for widening a bridge and a construction and calculation method thereof, which relates to the field of bridge structure design, including a steel joint; the steel joint includes: a steel casing, the steel casing is sleeved on the original bridge pier; one side of the steel casing has a first joint for sleeved the end of the original tie beam; the other side of the steel casing has a second joint for sleeved one end of a newly built tie beam; one end of the newly built tie beam is located in the second joint; the second joint has a number of welding nails connected to one end of the newly built tie beam; the other end of the newly built tie beam is integrally cast and connected to the newly built bridge pier. By adopting this scheme, the implantation of the original pier is eliminated, the damage to the original pier structure is avoided, and the tie beam body of the pure steel structure is replaced by a concrete tie beam. The steel structure is only used in the joint range, which ensures the integrity and earthquake resistance while greatly reducing the cost.

Description

Technical Field

[0001] The invention relates to the field of bridge structure design, and in particular to a combined tie beam structure for widening a bridge and a construction and calculation method thereof. Background Art

[0002] The tie beams of newly built bridges are usually connected to the steel bars of the bridge piers and cast together. However, when an existing bridge is widened, the tie beams of the newly built piers cannot be directly connected to the steel bars of the original piers. Generally, embedded steel bars or hoop-type steel tie beams are used.

[0003] The main reinforcement of the original bridge piers may be broken when drilling holes in the rebar embedding method, causing damage to the original bridge structure. The rebar embedding construction process is complicated. The hoop-type steel tie beam method is difficult to align with the original bridge tie beam, has poor integrity and seismic resistance, and the cost of the steel tie beam is very high. Summary of the invention

[0004] The present invention aims to solve the deficiencies of the prior art and to provide a composite tie beam structure for widening a bridge and a construction and calculation method thereof. By adopting this scheme, the embedded reinforcement of the original pier is eliminated, thus avoiding damage to the original pier structure. The tie beam body of the pure steel structure is replaced by a concrete tie beam, and the steel structure is only used in the joint range, which ensures the integrity and seismic resistance while greatly reducing the construction cost.

[0005] The present invention is achieved through the following technical solutions:

[0006] A composite tie beam structure for widening a bridge, including a steel joint;

[0007] The steel joint comprises:

[0008] A steel casing, wherein the steel casing is sleeved on the original bridge pier and located at the position of the original bridge pier and the original tie beam, and a square hole is opened on the side of the steel casing facing the original tie beam to avoid the original tie beam;

[0009] One side of the steel casing has a first joint for sleeve-mounting the end of the original tie beam; the other side of the steel casing has a second joint for sleeve-mounting one end of the newly-built tie beam; one end of the newly-built tie beam is located in the second joint;

[0010] The second joint is provided with a plurality of welding nails connected to one end of the newly-built tie beam;

[0011] The other end of the newly built tie beam is integrally cast and connected to the newly built bridge pier.

[0012] Compared with the prior art, the anchoring method will cause damage to the original bridge structure, and the hoop-type steel tie beam method is difficult to align with the original bridge tie beam, and the integrity and seismic resistance are poor, and the cost of the steel tie beam is very high. The present invention provides a combined tie beam structure for widening bridges and its construction and calculation method. With this scheme, the anchoring of the original piers is eliminated, which avoids damage to the original pier structure, and replaces the pure steel structure tie beam body with a concrete tie beam. The steel structure is only used in the joint range, which ensures the integrity and seismic resistance while greatly reducing the cost. In the specific scheme, a steel joint is included as an intermediate connector. The steel joint is similar to a four-way joint, which includes a steel casing and a first joint and a second joint located on both sides of the steel casing. The steel joint is arranged at the connection position between the original pier and the original tie beam, wherein the steel casing is sleeved and engaged on the original pier, and the first joint is sleeved and engaged on the original tie beam to achieve the fixation of the steel joint on the original tie beam to avoid slipping. The second joint is symmetrically arranged with the first joint, so that the newly built tie beam and the original tie beam can be quickly aligned while being convenient for connecting. At this time, one end of the newly built tie beam extends into the second joint and is connected by welding nails to improve the connection strength, while the other end is connected to the newly built bridge pier. The newly built bridge pier and the newly built tie beam are integrally poured with concrete to complete the installation of the widened bridge composite tie beam. In the above scheme, not only the planting of reinforcement in the original bridge pier is eliminated, thus avoiding damage to the structure; a large range of concrete tie beams are used to replace the tie beam body of the pure steel structure, and the steel structure is only used in the joint range, which greatly reduces the cost. The cost of a single composite tie beam is about 60% of that of a pure steel tie beam.

[0013] Further optimization, as a specific structure of a joint, the first joint and the second joint are both formed by welding together a plurality of side webs and a plurality of top and bottom plates.

[0014] Further optimization, in order to facilitate the rapid connection of the steel joint, the steel joint is a two-petal structure. In this solution, the steel joint can be completely split in the factory along the length direction of the tie beam during installation, thereby forming two two-petal structures that can be spliced ​​together. During the actual installation on site, the two-petal structures are spliced ​​together facing each other at the connection position between the original bridge pier and the original tie beam, and the two-petal structures are re-welded into a whole along the split direction.

[0015] In order to further optimize the connection strength and make the steel joint and the original bridge become a whole, the first grouting material is poured in the gaps between the steel joint and the original bridge pier and the original tie beam.

[0016] In a further optimization, in order to provide uniform shear resistance, a plurality of welding pins are evenly distributed on the peripheral side surface of the second joint.

[0017] Further optimization, in order to improve the overall connection strength, the end of the second joint is closed; the newly built tie beam has a number of longitudinal steel bars arranged along its own length direction, one end of the several longitudinal steel bars penetrates the closed end of the second joint and is welded to the side wall of the steel casing, and the other end of the several longitudinal steel bars is connected to the steel bars in the newly built bridge pier by steel bar binding. In this scheme, the end of the second joint is closed, so that the closed box-type structure formed by the second joint is convenient for pouring concrete in the second joint. The several longitudinal steel bars in the newly built tie beam have one end penetrated into the closed end and welded to the steel casing, and the other end is tied to the steel bars in the newly built bridge pier, so as to form a high-strength and high-stability overall structure.

[0018] In a further embodiment, the present invention also provides a construction method for a composite tie beam structure for widening a bridge, comprising the following steps:

[0019] Installing the steel joint as a whole on the original bridge pier, and pouring the first concrete in the gaps between the steel joint and the original bridge pier and the original tie beam;

[0020] After the installation is completed, the longitudinal steel bars in the newly built tie beam along its length direction are tied to the steel bars of the newly built bridge pier, and the end of the longitudinal steel bars away from the newly built bridge pier is welded to the side wall of the steel casing;

[0021] After the steel bars are connected, the second grouting material is cast at the other end of the newly built tie beam and the position of the newly built bridge pier, and the third grouting material is cast in the second joint. At this time, a post-casting section is reserved on the newly built tie beam between the second grouting material and the third grouting material;

[0022] After standing still for a period of time and the new bridge piers have settled, the fourth grouting material is poured in the post-casting section to complete the installation of the widened bridge composite tie beam.

[0023] Further optimization, the reserved length of the post-casting section is 80 to 100 cm.

[0024] In a further embodiment, the present invention also provides a calculation method for a composite tie beam structure for widening a bridge, comprising the steps of calculating the size of the steel joint;

[0025] The steps of calculating the steel joint size include:

[0026] The tensile bearing capacity provided by the top steel bar in the newly-built tie beam when it is stretched, and the shear bearing capacity provided by all the welded nails are obtained respectively;

[0027] Based on the principle of tie beam reinforcement tension and welded nail shear resistance, the size and number of welded nails required are obtained;

[0028] Finally, the size of the welding nail and the requirement that the welding nail diameter should not be greater than 1.5 times the thickness of the steel plate at the welding point are used to reversely calculate the basic plate thickness of the steel casing in the steel joint, the first joint and the second joint.

[0029] Further optimized, the calculation formula of the tensile bearing capacity provided by the top steel bars in the newly built tie beam when being pulled is f*S*n; wherein S is the area of ​​a single longitudinal steel bar inside the newly built tie beam; n is the number of longitudinal steel bars inside the newly built tie beam; and F is the tensile strength of the longitudinal steel bars inside the newly built tie beam;

[0030] The calculation formula for the shear bearing capacity of a single weld nail is: Where V su A is the shear bearing capacity of a single weld nail; su is the cross-sectional area of ​​the welding nail; E c is the elastic modulus of concrete; f cd is the design value of concrete axial compressive strength; f su It is the minimum tensile strength of the welding nail;

[0031] The calculation formula for the shear bearing capacity that all welding studs can provide is m*Vsu; where m is the number of welding studs.

[0032] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] 1. The present invention provides a combined tie beam structure for widening a bridge and a construction and calculation method thereof, which is connected to the original bridge by means of a hoop-type steel sleeve with a first grouting material poured inside, thereby eliminating the need for anchoring of the original piers and avoiding damage to the original piers caused by anchoring.

[0034] 2. The present invention provides a combined tie beam structure for widening a bridge and a construction and calculation method thereof. In view of the problem that in the prior art, the hoop-type steel sleeves generally avoid the position of the original bridge tie beam, the original piers and the newly built piers are connected to the piers through hoops, and a box-type steel tie beam is welded between the two steel sleeves. This pure steel tie beam is very expensive and requires a large amount of on-site welding. The present invention replaces the pure steel structure tie beam body with a large range of concrete tie beams, and only uses steel structures in the joint range, which greatly reduces the cost. The cost of a single combined tie beam is about 60% of that of a pure steel tie beam.

[0035] 3. The present invention provides a combined tie beam structure for widening a bridge and a construction and calculation method thereof, which adopts a steel plate connected to welded nails to bear force together with concrete, and adopts the principle of equal strength of the tie beam steel bars being subjected to tension and the welded nails being subjected to shear, to ensure that steel and concrete are effectively combined and bear the role together.

[0036] 4. The present invention provides a combined tie beam structure for widening a bridge and a construction and calculation method thereof. By opening a hole at the original tie beam position and reinforcing the steel joint, the problem that the newly built tie beam is difficult to align with the original bridge tie beam is solved, and the problem that the clamp may slide down is solved. The main force-bearing top and bottom plates are set up as a whole plate on both sides of the original bridge pier, and the force transmission effect is much better than the top and bottom plates of the pure steel tie beam in the prior art, which are only connected to the clamp weld on one side of the newly built tie beam.

[0037] 5. The present invention provides a combined tie beam structure for widening a bridge and a construction and calculation method thereof. The steel sleeve and the steel plate welded thereon together form a steel joint similar to a four-way joint, which can be longitudinally cut after being formed in the factory and connected with only one weld after being assembled on site, thereby achieving the effects of convenient construction, economy and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0039] Figure 1 A front view of the combined tie beam structure provided by the present invention;

[0040] Figure 2 A top view of the combined tie beam structure provided by the present invention;

[0041] Figure 3 A side view of a second joint provided by the present invention;

[0042] Figure 4 A side view of the steel casing provided by the present invention;

[0043] Figure 5 A schematic diagram of the distribution and connection of the internal reinforcement bars of a newly constructed tie beam provided by the present invention;

[0044] Figure 6 A side view of the newly constructed tie beam provided by the present invention.

[0045] Marks and corresponding parts names in the attached drawings:

[0046] 1-steel casing, 2-original pier, 3-original tie beam, 4-new tie beam, 5-new pier, 6-weld nails, 7-longitudinal reinforcement, 8-side web, 9-top and bottom plates, 10-second grouting material, 11-third grouting material, 12-fourth grouting material. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0048] Embodiment 1:

[0049] This embodiment 1 provides a composite tie beam structure for widening a bridge, such as Figure 1-Figure 6 As shown, including steel joints;

[0050] The steel joint comprises:

[0051] A steel casing 1, wherein the steel casing 1 is sleeved on the original bridge pier 2 and located at the position of the original bridge pier 2 and the original tie beam 3, and a square hole is opened on the side of the steel casing 1 facing the original tie beam 3 to avoid the original tie beam 3;

[0052] One side of the steel casing 1 has a first joint for sleeve-mounting the end of the original tie beam 3; the other side of the steel casing 1 has a second joint for sleeve-mounting one end of the newly-built tie beam 4; one end of the newly-built tie beam 4 is located in the second joint;

[0053] The second joint is provided with a plurality of welding studs 6 connected to one end of the newly-built tie beam 4;

[0054] The other end of the newly built tie beam 4 is integrally cast and connected to the newly built bridge pier 5 .

[0055] Compared with the prior art, the anchoring method will cause damage to the original bridge structure, and the hoop-type steel tie beam method is difficult to align with the original bridge tie beam, and the integrity and seismic resistance are poor, and the cost of the steel tie beam is very high. The present invention provides a combined tie beam structure for widening the bridge and its construction and calculation method. With this scheme, the anchoring of the original pier 2 is eliminated, the damage to the structure of the original pier 2 is avoided, and the tie beam body of the pure steel structure is replaced by a concrete tie beam. The steel structure is only used in the joint range, which ensures the integrity and seismic resistance while greatly reducing the cost. In the specific scheme, a steel joint is included as an intermediate connector. The steel joint is similar to a four-way joint, which includes a steel casing 1 and a first joint and a second joint located on both sides of the steel casing 1. The steel joint is set at the connection position between the original pier 2 and the original tie beam 3, wherein the steel casing 1 is sleeved and engaged on the original pier 2, and the first joint is sleeved and engaged on the original tie beam 3, so as to achieve the fixation of the steel joint on the original tie beam 3 to avoid slipping. The second joint is symmetrically arranged with the first joint, so that the newly built tie beam 4 and the original tie beam 3 can be quickly aligned while being convenient for connecting the newly built tie beam 4; at this time, one end of the newly built tie beam 4 extends into the second joint and is connected by a welding nail 6 to improve the connection strength, and the other end is connected to the newly built bridge pier 5, and the newly built bridge pier 5 and the newly built tie beam 4 are integrally cast by concrete to complete the installation of the widened bridge composite tie beam. In the above scheme, not only the planting of reinforcement for the original bridge pier 2 is cancelled, thus avoiding damage to the structure; a large range of concrete tie beams are used to replace the tie beam body of the pure steel structure, and the steel structure is only used in the joint range, which greatly reduces the cost. The cost of a single composite tie beam is about 60% of that of a pure steel tie beam.

[0056] In this embodiment, as a specific structure of a joint, the first joint and the second joint are both formed by welding together a plurality of side webs 8 and a plurality of top and bottom plates 9 .

[0057] In this embodiment, in order to facilitate the rapid connection of the steel joint, the steel joint is a two-petal structure. In this solution, the steel joint can be completely split in the factory along the length direction of the tie beam during installation, so as to form two two-petal structures that can be spliced ​​together. During the actual installation on site, the two-petal structures are spliced ​​together facing each other at the connection position of the original pier 2 and the original tie beam 3, and the two-petal structures are re-welded into a whole along the split direction.

[0058] In this embodiment, in order to improve the connection strength and make the steel joint and the original bridge become a whole, the first grouting material is poured in the gaps between the steel joint and the original bridge pier 2 and the original tie beam 3.

[0059] In this embodiment, in order to provide uniform shear resistance, a plurality of welding pins 6 are evenly distributed on the peripheral side surface of the second joint.

[0060] In this embodiment, in order to improve the overall connection strength, the second joint end is closed; the newly built tie beam 4 has a plurality of longitudinal steel bars 7 arranged along its length direction, one end of the plurality of longitudinal steel bars 7 penetrates the closed end of the second joint and is welded to the side wall of the steel casing 1, and the other end of the plurality of longitudinal steel bars 7 is connected to the steel bars in the newly built bridge pier 5 by steel bar binding. In this solution, the second joint end is closed, so that the closed box-type structure formed by the second joint is convenient for pouring concrete in the second joint. The plurality of longitudinal steel bars 7 in the newly built tie beam 4 have one end penetrated into the closed end and welded to the steel casing 1, and the other end is bound to the steel bars in the newly built bridge pier 5, thereby forming a high-strength, high-stability overall structure.

[0061] Embodiment 2:

[0062] This embodiment 2 is further optimized on the basis of embodiment 1, and also provides a construction method for a composite tie beam structure for widening a bridge, comprising the following steps:

[0063] The entire steel joint similar to the four-way joint type is cut open vertically, formed in the factory, and then roughened on site. The steel joint is installed as a whole on the original pier 2, and the first concrete is poured in the gaps between the steel joint and the original pier 2 and the original tie beam 3.

[0064] After the installation is completed, the longitudinal steel bars 7 along the length direction of the newly built tie beam 4 are tied to the steel bars of the newly built bridge pier 5, and the end of the longitudinal steel bars 7 away from the newly built bridge pier 5 is welded to the side wall of the steel casing 1;

[0065] After the steel bar connection is completed, the second grouting material 10 is normally cast and formed at the other end of the newly built tie beam 4 and the position of the newly built pier 5, and the third grouting material 11 is cast in the box section formed by the second joint, thereby working together with the weld nails 6 in the box to form an effective combination of steel and concrete. At this time, a post-casting section is reserved on the newly built tie beam 4 between the second grouting material 10 and the third grouting material 11, and the reserved length of the post-casting section is 80 to 100 cm.

[0066] After a period of standing, the new bridge pier 5 has settled and most of the shrinkage creep has been completed, and the fourth grouting material 12 is poured at the post-casting section, thereby completing the installation of the widened bridge composite tie beam. The first grouting material is epoxy concrete or high-strength grouting material, the second grouting material 10 is ordinary concrete, and the third grouting material 11 and the fourth grouting material 12 are shrinkage compensation concrete or high-strength grouting material.

[0067] Embodiment 3:

[0068] This embodiment 3 is a further optimization based on embodiment 1, and also provides a calculation method for a composite tie beam structure for widening a bridge.

[0069] Since the shrinkage compensation concrete of the newly built tie beam 4 is poured in the closed box section of the steel joint, that is, in the second joint, and works together with the weld nails 6 in the box, the calculation is carried out using the principle that the tie beam steel bar is tensile and the weld nails 6 are shear-resistant, thereby ensuring that the steel and concrete are effectively combined and work together. Therefore, the step of calculating the size of the steel joint is included;

[0070] The steps of calculating the steel joint size include:

[0071] Since the tie beam is subjected to transverse bending moment under earthquake action, it is specifically manifested as alternating tension of the top and bottom reinforcements. Taking the top reinforcement as an example, the longitudinal reinforcement 7 of the newly built tie beam 4 is usually consistent with the original tie beam 3. Assuming that the area of ​​a single longitudinal reinforcement 7 is S, the number of reinforcements is n, and the tensile strength of the longitudinal reinforcement 7 is f, the tensile bearing capacity that the top reinforcement can provide when it is tensile is f*S*n. After adopting the steel-concrete composite tie beam, the tensile force of the original top reinforcement is provided by the shear resistance of the top welded nails 6.

[0072] In addition, the shear bearing capacity of a single welding nail 6 is calculated as follows:

[0073]

[0074] Where V su A is the shear bearing capacity of a single weld nail; su is the cross-sectional area of ​​the welding nail; E c is the elastic modulus of concrete; f cd is the design value of concrete axial compressive strength; f su It is the minimum tensile strength of the welding nail;

[0075] Assuming there are m welding nails 6, the shear bearing capacity that all welding nails 6 can provide is m*V su ;

[0076] Based on the principle that the tie beam reinforcement is tensile and the welded nails 6 are equally strong, f*S*n=m*V su , the size and quantity of the welding nails 6 to be set can be calculated.

[0077] Finally, the basic plate thickness of the steel casing 1 in the steel joint, the first joint and the second joint are determined by reverse calculation based on the size of the welding nail 6 and the requirement that the diameter of the welding nail 6 is not greater than 1.5 times the thickness of the steel plate at the welding point.

[0078] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite tie beam structure for widening a bridge, characterized in that: Includes steel joints; The steel joint comprises: A steel casing (1), the steel casing (1) being sleeved on the original bridge pier (2) and located at the position of the original bridge pier (2) and the original tie beam (3), and the steel casing (1) having a square hole on one side facing the original tie beam (3) for avoiding the original tie beam (3); One side of the steel casing (1) is provided with a first joint for sleeve-mounting the end of the original tie beam (3); the other side of the steel casing (1) is provided with a second joint for sleeve-mounting one end of the newly-built tie beam (4); one end of the newly-built tie beam (4) is located in the second joint; The second joint is provided with a plurality of welding studs (6) connected to one end of the newly-built tie beam (4); The other end of the newly built tie beam (4) is integrally cast and connected to the newly built bridge pier (5).

2. A composite tie beam structure for widening a bridge according to claim 1, characterized in that: The first joint and the second joint are formed by welding together a plurality of side webs (8) and a plurality of top and bottom plates (9).

3. The combined tie beam structure for widening a bridge according to claim 1, characterized in that: The steel joint is a two-petal structure.

4. The combined tie beam structure for widening a bridge according to claim 1, characterized in that: The first grouting material is poured in the gaps between the steel joint and the original bridge pier (2) and the original tie beam (3).

5. The combined tie beam structure for widening a bridge according to claim 1, characterized in that: A plurality of welding pins (6) are evenly distributed on the peripheral side surface of the second joint.

6. The combined tie beam structure for widening a bridge according to claim 1, characterized in that: The second joint end is closed; The newly built tie beam (4) has a plurality of longitudinal steel bars (7) arranged along its length direction. One end of the plurality of longitudinal steel bars (7) penetrates into the closed end of the second joint and is welded to the side wall of the steel casing (1). The other end of the plurality of longitudinal steel bars (7) is connected to the steel bars in the newly built bridge pier (5) by steel bar binding.

7. A construction method for a composite tie beam structure for widening a bridge according to any one of claims 1 to 6, characterized in that: The following steps are involved: The steel joint is integrally installed on the original bridge pier (2), and the first grouting material is poured in the gaps between the steel joint and the original bridge pier (2) and the original tie beam (3); After the installation is completed, the longitudinal steel bars (7) in the newly built tie beam (4) along its own length direction are tied to the steel bars of the newly built bridge pier (5), and the end of the longitudinal steel bars (7) away from the newly built bridge pier (5) is welded to the side wall of the steel casing (1); After the steel bars are connected, the second grouting material (10) is cast at the other end of the newly built tie beam (4) and the position of the newly built bridge pier (5), and the third grouting material (11) is cast in the second joint. At this time, a post-casting section is reserved on the newly built tie beam (4) between the second grouting material (10) and the third grouting material (11); After standing still for a period of time and the newly built bridge pier (5) has settled, the fourth grouting material (12) is poured at the post-casting section, thereby completing the installation of the widened bridge composite tie beam.

8. The construction method of the composite tie beam structure for widening a bridge according to claim 7, characterized in that: The reserved length of the post-casting section is 80 to 100 cm.

9. A calculation method for a composite tie beam structure for widening a bridge according to any one of claims 1 to 6, characterized in that: The method comprises the steps of calculating the size of the steel joint; The steps of calculating the steel joint size include: The tensile bearing capacity provided by the top steel bar in the newly-built tie beam (4) when it is stretched, and the shear bearing capacity provided by all the welded nails (6) are obtained respectively; Based on the principle that the tie beam reinforcement is tensile and the weld nails are shear resistant, the size and number of the weld nails (6) to be set are obtained; Finally, the basic plate thickness of the steel sleeve (1) in the steel joint, the first joint and the second joint is determined by reverse calculation based on the size of the welding nail (6) and the requirement that the diameter of the welding nail (6) is not greater than 1.5 times the thickness of the steel plate at the welding point.

10. A calculation method for a composite tie beam structure for widening a bridge according to claim 9, characterized in that: The calculation formula for the tensile bearing capacity provided by the top steel bars in the newly built tie beam (4) when being pulled is f*S*n; wherein S is the area of ​​a single longitudinal steel bar (7) inside the newly built tie beam (4); n is the number of longitudinal steel bars (7) inside the newly built tie beam (4); and F is the tensile strength of the longitudinal steel bars (7) inside the newly built tie beam (4); The calculation formula for the shear bearing capacity of a single weld nail is: Where V su A is the shear bearing capacity of a single weld nail; su is the cross-sectional area of ​​the welding nail; E c is the elastic modulus of concrete; f cd is the design value of concrete axial compressive strength; f su It is the minimum tensile strength of the welding nail; The calculation formula for the shear bearing capacity that all welding studs can provide is m*Vsu; where m is the number of welding studs.

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