Steel truss for reducing jacking node stress

Abstract

The utility model discloses a steel truss for reducing the stress of pushing node, solved the problem that the local negative bending moment of steel truss girder construction in the prior art increases, cannot effectively pass through the oblique web member and the vertical and horizontal beam and is distributed on the rest support component, the utility model discloses a main girder and the guide beam that cooperates with main girder, the detachable connection of main girder and guide beam junction has the temporary web, and the lower part of main girder and guide beam is connected with the temporary pier. The utility model increases the temporary vertical web of assembling in the permanent component structure, and the interval of greater deformation is locked in advance, to increase the node support condition, and the vertical web has the assembling function simultaneously, can realize the recycling application to the vertical reinforcement of steel truss girder of different beam height, effectively reduces the interval bending moment, reduces the chord force in the compatibility of recycling performance, adjustable performance, meets the requirement of green construction, resource recycling.

Description

Technical Field

[0001] This utility model relates to the field of steel truss jacking construction technology, and in particular to a steel truss for reducing stress at jacking nodes. Background Technology

[0002] In the jacking construction of steel trusses, the main truss structure is typically composed of three parts: the upper chord, the lower chord, and the diagonal web members. During the step-by-step jacking construction, the steel truss gradually moves forward under the action of the jacking device. Throughout this process, the steel truss is constantly under stress. When the hydraulic jacking is at the midpoint of the triangular section, the local negative bending moment increases due to the section dimensions. This moment cannot be effectively transferred to the remaining supporting components through the diagonal web members and longitudinal and transverse beams, potentially causing permanent damage to the main truss structure.

[0003] A novel guide beam, as described in application number 202310963157.3, includes at least two truss structures connected by square steel. Each truss structure comprises a triangular truss consisting of a lower chord, an upper chord, multiple vertical web members, and multiple diagonal web members. The lower chord includes n nodes and n segments, and the upper chord includes m nodes and m segments. The nodes of the lower chord are connected to the nodes of the upper chord via vertical web members. The odd-numbered nodes of the lower chord are connected to the even-numbered nodes of the adjacent upper chord via corresponding diagonal web members. When the cross-sectional dimensions of each node and the connected segment are different, a transition connection is achieved by gradually changing the dimensions of a box-shaped cross-section, and the thickness of the box-shaped cross-section at each node is greater than or equal to the thickness of the box-shaped cross-section of the adjacent segment. Although this patent achieves the goal of enhancing the stability of the steel truss structure, installing multiple vertical web members increases the weight of the guide beam, affecting the overall stability of the device. Utility Model Content

[0004] To address the shortcomings in the aforementioned background technology, this utility model proposes a steel truss for reducing the stress at the jacking node, which solves the problem in the prior art where the local negative bending moment increases during the construction of steel trusses and cannot be effectively transferred to other supporting components for distribution through diagonal web members and longitudinal and transverse beams.

[0005] The technical solution of this utility model is implemented as follows: a steel truss for reducing the stress at the jacking node includes a main beam and a guide beam that cooperates with the main beam. A temporary web member is detachably connected at the connection between the main beam and the guide beam, and a temporary pier is connected at the lower part of the main beam and the guide beam.

[0006] More preferably, the temporary web member includes two symmetrically arranged vertical adjustable telescopic rods, and both the upper and lower sides of the vertical adjustable telescopic rods are connected to the main beam by bolts.

[0007] More preferably, the vertically adjustable telescopic rod includes an upper connecting rod and a lower connecting rod. The lower part of the upper connecting rod is provided with a reinforcing connecting plate that connects to the upper part of the lower connecting rod, and both the upper part of the upper connecting rod and the lower part of the lower connecting rod are provided with a base plate that connects to the main beam.

[0008] More preferably, both the upper connecting rod and the lower connecting rod are I-shaped rods.

[0009] More preferably, the main beam and the guide beam each include a lower chord beam and an upper chord beam corresponding to the lower chord beam. The lower chord beam is provided with several oblique web members and is connected to the upper chord beam through the oblique web members. The lower chord beam and the upper chord beam are connected to form several triangular structures through the oblique web members.

[0010] More preferably, the upper chord beam includes several sets of symmetrically arranged upper chord members, with several horizontal and vertical connecting rods connecting two upper chord members, and the upper chord members are also provided with a vertical joint corresponding to the diagonal web members.

[0011] More preferably, the lower chord beam includes several sets of symmetrically arranged lower chord members, with several horizontal and vertical connecting rods connected between two lower chord members, and the lower chord members are also provided with vertical joints corresponding to the inclined web members.

[0012] More preferably, both the upper chord and the lower chord are provided with transverse joints.

[0013] More preferably, both the upper chord and the lower chord are box-type steel pipes.

[0014] More preferably, the box-shaped steel pipe is provided with reinforcing ribs.

[0015] The beneficial effects of this utility model are as follows: This utility model adds temporary vertical web members to the permanent structural members, locks the sections with large stress and large deformation in advance to increase the support conditions of the nodes. At the same time, the vertical web members have the function of assembly, which can be reused in the vertical reinforcement of steel trusses with different beam heights, effectively reducing the bending moment between sections and reducing the internal force of the chord members, while also having the performance of turnover and adjustability, which meets the requirements of green construction and resource recycling. Attached Figure Description

[0016] To more clearly illustrate the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a structural diagram of the present invention;

[0018] Figure 2This is a schematic diagram showing the connection between the upper chord beam and the lower chord beam, and the diagonal and vertical web members of this utility model.

[0019] Figure 3 Top view of the upper chord of this utility model Figure 1 ;

[0020] Figure 4 Top view of the upper chord of this utility model Figure 2 ;

[0021] Figure 5 for Figure 4 Cross-sectional view of AA;

[0022] Figure 6 This is a top view of the lower chord of this utility model;

[0023] Figure 7 This is a side view of the vertically adjustable telescopic rod of this utility model.

[0024] The following are the labels in the diagram: 1. Bridge pile foundation; 2. Temporary pier; 3. Main beam; 4. Temporary web member; 5. Guide beam; 6. Upper chord; 7. Transverse joint one; 8. Horizontal and longitudinal connecting rod one; 9. Lower chord; 10. Transverse joint two; 11. Horizontal and longitudinal connecting rod two; 12. Diagonal web member; 12-1. Lower connecting rod; 12-2. Upper connecting rod; 12-3. Connecting plate; 12-4. Base plate; 13. Vertical joint; 14. Reinforcing rib plate. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] like Figure 1 and Figure 2 As shown in Embodiment 1, a steel truss for reducing stress at jacking nodes includes a main beam 3 and a guide beam 5 that cooperates with the main beam 3. A temporary web member 4 is detachably connected at the connection between the main beam 3 and the guide beam 5, and a temporary pier 2 is connected to the lower part of the main beam 3 and the guide beam 5. This utility model adds assembled temporary vertical web members to the permanent structural members, locking the sections with large stress and deformation in advance to increase the support conditions at the nodes. At the same time, the vertical web members have an assembly function, which can be reused for the vertical reinforcement of steel trusses with different beam heights, effectively reducing the bending moment between sections and the internal force of the chord members, while also having reusability and adjustability, meeting the requirements of green construction and resource recycling.

[0027] like Figure 7As shown, in this embodiment, the temporary web member 4 includes two symmetrically arranged vertically adjustable telescopic rods, both the upper and lower sides of which are connected to the main beam 3 by bolts. Each vertically adjustable telescopic rod includes an upper connecting rod 4-2 and a lower connecting rod 4-1. The lower part of the upper connecting rod 4-2 is provided with a reinforcing connecting plate 4-3 that connects to the upper part of the lower connecting rod 4-1. Both the upper part of the upper connecting rod 4-2 and the lower part of the lower connecting rod 4-1 are provided with a base plate 4-4 that connects to the main beam 3. Both the upper connecting rod 4-2 and the lower connecting rod 4-1 are I-beam members. The I-beam members are I-beams, and the two I-beams achieve the telescopic performance of the web member through the connecting plate 4-3, enabling it to be used interchangeably for temporary vertical support of steel truss beams with different beam heights. Vertical web members are installed on the guide beam 5. Vertical web members are installed along the entire height of the triangular truss. The upper part is connected to the upper chord 6 and the lower chord 9 with high-strength bolts. The high-strength bolts are pre-embedded in the holes during the fabrication of the upper and lower chord 9. The top position is required to be accurate and the deviation of the plane position is controlled within 1mm. CNC machine tools are used for positioning and pre-embedding. The anchor bolts only provide a fixing function.

[0028] like Figures 3-6 As shown in Embodiment 2, a steel truss for reducing stress at jacking nodes includes a main beam 3 and a guide beam 5, each comprising a lower chord beam and a corresponding upper chord beam. The lower chord beam has several diagonal web members 12 connected to the upper chord beam via these web members 12. The lower and upper chord beams are connected by the diagonal web members 12 to form several triangular structures. Utilizing the geometric stability of triangles, the structural stress and performance are optimized, loads are transferred, internal force concentration is reduced, overall stability is enhanced, deformation is resisted, material usage is reduced, and lightweighting is achieved.

[0029] In this embodiment, the upper chord beam includes several sets of symmetrically arranged upper chord members 6, with several horizontal and vertical connecting rods 8 connecting two upper chord members 6. Each upper chord member 6 also has a vertical joint 7 corresponding to the diagonal web member 12. The lower chord beam includes several sets of symmetrically arranged lower chord members 9, with several horizontal and vertical connecting rods 11 connecting two lower chord members 9. Each lower chord member 9 also has a vertical joint 10 corresponding to the diagonal web member 12. Both the upper chord members 6 and the lower chord members 9 have transverse joints. Both the upper chord members 6 and the lower chord members 9 are box-shaped steel pipes. Reinforcing ribs 14 are provided inside the box-shaped steel pipes. This design optimizes material utilization while significantly improving the load-bearing capacity and structural stability of the components, enhancing cross-sectional stiffness and deformation resistance, increasing the load-bearing limit of the components, extending service life, and balancing lightweight and economic efficiency.

[0030] All other structures are the same as in Example 1.

[0031] Specifically, modeling was performed before construction: Based on existing drawings, the main beam 3 and guide beam 5 were modeled as trusses, with the two trusses corresponding to guide beams 5 of different lengths: 41.796m and 57.282m respectively. Pile foundation supports 1 were installed at the lower part of temporary pier 2, and vertical constraints were applied to the corresponding positions of the jacking temporary pier 2. The self-weight loads of the trusses, concrete panels, and guide beam 5, as well as the ratio of calculated stress to design strength, were calculated, taking stability reduction into account. The calculation process used a safety factor of 1.5, dividing the analysis model into 2.5m sections. Chord member positions with stress ratios exceeding 0.8 * 0.8 * 330 = 264 MPa were identified.

[0032] Due to the influence of the skewed construction of the bridge, temporary piers were arranged at an angle to reduce the cantilever size. As the jacking equipment gradually pushes the steel truss forward, it inevitably pushes the node operating platform at a single point in the 2-3 interval. When the node is at the center of the lower chord of the triangular truss, the internal force of the steel truss structure is at its maximum. Calculations show that the stress ratio at this point is greater than 0.8 of Q390D, resulting in insufficient structural safety factor. Therefore, after optimization, a vertically adjustable telescopic rod was added at the center of the first segment at the front end of the main truss to reduce the segment span and decrease the internal force. Similarly, as the jacking process continues, the left side will be the first to be jacked up. Besides the guide beam 5 bearing the load, the left side of the main truss will inevitably be jacked up at a single point. To reduce permanent damage to the main truss, a vertically adjustable telescopic rod was added at the location where the stress ratio exceeds 0.8.

[0033] After the guide beam 5 detaches from the temporary pier 2, the rear support point is jointly supported by other temporary piers 2. The left support point is under single-support stress, with the largest bending moment. Adding vertical web members at this point can reduce the inter-segment stress under this working state, keeping the stress ratio within 0.8, and greatly reducing the irreversible deformation of the main truss structure during installation. The steel truss beam has a clear span of 105m, a steel structure weight of approximately 1880t, and an additional 350t of load with the plate, bringing the total weight of a single span to approximately 2230t. Based on 3D3S (v2021) finite element analysis software, the entire jacking process was stress-analyzed and simulated. The inter-segments with large stress and deformation were locked in advance. Temporary vertical web members were added to the permanent structural members to increase the support conditions at the nodes. At the same time, the vertical web members have an assembly function, allowing them to be reused for vertical reinforcement of steel trusses with different beam heights. This device effectively reduces the inter-segment bending moment and the internal force of the chord members while also possessing reusability and adjustability, meeting the requirements of green construction and resource recycling.

[0034] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A steel truss for reducing stress at jacking nodes, characterized in that, It includes a main beam (3) and a guide beam (5) that cooperates with the main beam (3). A temporary web member (4) is detachably connected at the connection between the main beam (3) and the guide beam (5). A temporary pier (2) is connected at the lower part of the main beam (3) and the guide beam (5).

2. The steel truss for reducing stress at the jacking node according to claim 1, characterized in that: The temporary web member (4) includes two symmetrically arranged vertical adjustable telescopic rods, and the upper and lower sides of the vertical adjustable telescopic rods are connected to the main beam (3) by bolts.

3. The steel truss for reducing stress at the jacking node according to claim 2, characterized in that: The vertically adjustable telescopic rod includes an upper connecting rod (4-2) and a lower connecting rod (4-1). The lower part of the upper connecting rod (4-2) is provided with a reinforcing connecting plate (4-3) that is connected to the upper part of the lower connecting rod (4-1). The upper part of the upper connecting rod (4-2) and the lower part of the lower connecting rod (4-1) are both provided with a base plate (4-4) that is connected to the main beam (3).

4. The steel truss for reducing stress at the jacking node according to claim 3, characterized in that: Both the upper connecting rod (4-2) and the lower connecting rod (4-1) are I-shaped members.

5. The steel truss for reducing stress at the launching node according to any one of claims 2 to 4, characterized in that: The main beam (3) and the guide beam (5) each include a lower chord beam and an upper chord beam corresponding to the lower chord beam. The lower chord beam is provided with several oblique web members (12) and is connected to the upper chord beam through the oblique web members (12). The lower chord beam and the upper chord beam are connected to form several triangular structures through the oblique web members (12).

6. The steel truss for reducing stress at the jacking node according to claim 5, characterized in that: The upper chord beam includes several sets of symmetrically arranged upper chord members (6), and several horizontal and vertical connecting rods (8) are connected between two upper chord members (6). The upper chord members (6) are also provided with vertical joints (7) corresponding to the inclined web members (12).

7. The steel truss for reducing stress at the jacking node according to claim 6, characterized in that: The lower chord beam includes several sets of symmetrically arranged lower chord members (9), and several horizontal and vertical connecting rods (11) are connected between two lower chord members (9). The lower chord members (9) are also provided with vertical joints (10) corresponding to the inclined web members (12).

8. The steel truss for reducing stress at the jacking node according to claim 7, characterized in that: Both the upper chord (6) and the lower chord (9) are provided with transverse joints (13).

9. The steel truss for reducing stress at the jacking node according to claim 7 or 8, characterized in that: Both the upper chord (6) and the lower chord (9) are box-type steel pipes.

10. The steel truss for reducing stress at the launching node according to claim 9, characterized in that: The box-shaped steel pipe is equipped with reinforcing ribs (14).

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