Construction method for optimizing initial stress of steel truss girder upper-layer road cross beam

Abstract

The invention discloses a construction method for optimizing the initial stress of a steel truss girder upper-layer road cross beam, which comprises the following specific processes: in a segment prefabrication stage, performing permanent connection and temporary connection of a steel truss girder upper-layer road longitudinal beam and a road cross beam; in the incremental launching construction stage, the temporary connecting structure does not limit the longitudinal relative displacement; in the deformation coordination stage, deformation coordination of the road longitudinal beam and the main truss upper chord is carried out; in the structural consolidation stage, temporary connection is dismantled and converted into permanent connection; in the bridge deck repairing and paving stage, the prefabricated highway bridge deck is repaired and paved, and construction of the highway bridge deck system is completed. The steel truss girder is divided into n sections and one section, the prefabricated highway bridge deck slabs laid at the continuous sections firstly are used for deformation coordination of the highway longitudinal beams and the main truss upper chords, a temporary ballasting device is avoided, and the problem that the stress of the cross beams exceeds the limit under the effects of bridge deck slab construction, second-stage dead load and live load is solved. Materials are saved, economical efficiency is high, construction efficiency is improved, and the project progress is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of bridge engineering, and in particular relates to a construction method for optimizing the initial stress of a steel truss upper highway beam. Background Art

[0002] During the jacking construction of long-span steel trusses, the upper highway bridge deck system typically utilizes a longitudinal and transverse beam system. Traditional construction methods complete the permanent connection of all highway crossbeams and longitudinal beams prior to jacking. However, due to the significant difference in stiffness between the upper chord of the steel truss main girders and the upper highway longitudinal beams, after jacking, the deadweight of the structure causes an incoordination in the longitudinal deformation of the two, which in turn generates initial out-of-plane stress in the highway beams. This initial stress will be further compounded by subsequent bridge deck construction, secondary dead loads, and live loads, resulting in excessive beam stress. Design requirements must be met by increasing the cross-sectional dimensions of the components or installing reinforcement structures. However, reinforcing the entire length of the bridge results in material waste and poor economic efficiency. Furthermore, the traditional temporary connection structure cannot be disassembled, impacting construction efficiency. Summary of the Invention

[0003] The present invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a construction method for optimizing the initial stress of the upper highway crossbeam of a steel truss beam.

[0004] The technical solution of the present invention is: a construction method for optimizing the initial stress of the upper highway beam of a steel truss beam, comprising the following steps: A. During the segment prefabrication stage, permanent and temporary connections are made to the upper highway longitudinal beams and highway cross beams of the steel trusses; B. During the jacking construction phase, the temporary connection structure does not restrict the longitudinal relative displacement; C. During the deformation coordination stage, the deformation coordination of the highway longitudinal beam and the main truss upper chord is carried out; D. During the structural consolidation stage, temporary connections are removed and replaced with permanent connections; E. During the bridge deck repair phase, prefabricated highway bridge panels are repaired to complete the construction of the highway bridge deck system.

[0005] Furthermore, the permanent connection in step A is as follows: First, when the steel trusses are assembled in segments, continuous (n+1) standard spans are formed; Then, the first n standard internodes constitute the continuous internodes; Finally, the highway longitudinal beams and highway cross beams in the continuous intervals are permanently connected.

[0006] Furthermore, the temporary connection in step A is as follows: First, when the steel trusses are assembled in segments, continuous standard spans are formed; Then, the n+1th standard internode is the disconnected internode; Finally, the longitudinal highway girders and transverse highway girders in the disconnected bays are temporarily connected using temporary horse plates that allow longitudinal sliding.

[0007] Furthermore, the continuous bays and disconnected bays form a periodic structure of n continuous and 1 disconnected.

[0008] Furthermore, in step B during the incremental launching construction stage, the temporary connection structure does not restrict the longitudinal relative displacement, and the specific process is as follows: First, perform the overall incremental launching operation of the steel truss girder; Then, during the incremental launching operation, the temporary horse plates do not restrict the longitudinal relative displacement between the longitudinal highway girders and the transverse highway girders.

[0009] Furthermore, in step C during the deformation coordination stage, perform the deformation coordination between the longitudinal highway girders and the upper chords of the main trusses, and the specific process is as follows: First, after the operation is in place, use a bridging machine to lay precast highway bridge decks in the continuous bays; Then, utilize the self-weight of the precast highway bridge decks to promote the deformation coordination between the longitudinal highway girders and the upper chords of the main trusses.

[0010] Furthermore, in step D during the structure consolidation stage, remove the temporary connection and convert it to a permanent connection, and the specific process is as follows: First, after the deformation in step C is stable, remove the temporary horse plates in the disconnected bays; Then, complete the permanent connection of the disconnected bays.

[0011] Furthermore, in step E during the bridge deck patching stage, patch the precast highway bridge decks to complete the construction of the highway bridge deck system, and the specific process is as follows: Use a bridging machine to patch the precast highway bridge decks at the positions of the consolidated disconnected bays to complete the construction of the highway bridge deck system.

[0012] The beneficial effects of the present invention are as follows: The present invention divides the steel truss girder into a structure of n continuous and 1 disconnected, and uses the precast highway bridge decks laid first in the continuous bays to coordinate the deformation of the longitudinal highway girders and the upper chords of the main trusses, avoiding the investment in temporary ballast devices, and solving the problem of over-limit stress in the cross girders caused by the construction of the bridge deck, the secondary dead load, and the live load.

[0013] The present invention does not require increasing the cross-sectional size of components or setting up strengthening structures to meet the design requirements, saves materials, has high economy, and improves the construction efficiency and ensures the project progress through detachable temporary horse plates. Brief Description of the Drawings

[0014] Figure 1 is a schematic diagram of step A in the present invention; Figure 2It is a schematic diagram of step B in the present invention; Figure 3 It is a schematic diagram of step C in the present invention; Figure 4 It is a schematic diagram of step D in the present invention; Figure 5 It is a schematic diagram of step E in the present invention; Figure 6 It is a detailed construction drawing of a connection node of a temporary horse plate in the present invention; Figure 7 It is another detailed construction drawing of a connection node of a temporary horse plate in the present invention; Figure 8 It is a schematic diagram of using the upper chord as a temporary transportation passage for precast highway bridge decks in the present invention; Wherein: 10 - steel truss girder; 11 - upper chord of the main truss; 12 - lower chord of the main truss; 13 - web member of the main truss; 14 - railway bridge deck system; 15 - highway longitudinal beam; 16 - highway cross beam; 20 - standard bay; 21 - continuous bay; 22 - discontinuous bay; 30 - temporary horse plate; 31 - temporary splicing plate; 32 - ordinary bolt; 33 - oblong hole; 34 - vertical support plate; 35 - horizontal limit clamping plate; 40 - precast highway bridge deck; 50 - girder erecting machine. Specific embodiments

[0015] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and embodiments: As Figures 1 to 8 shown, a construction method for optimizing the initial stress of the upper highway cross beam of a steel truss girder includes the following steps: A. In the segment prefabrication stage, perform permanent connection and temporary connection of the upper highway longitudinal beam 15 and highway cross beam 16 of the steel truss girder 10; B. In the jacking construction stage, the temporary connection structure does not restrict the longitudinal relative displacement; C. In the deformation coordination stage, perform deformation coordination between the highway longitudinal beam 15 and the upper chord 11 of the main truss; D. In the structure consolidation stage, remove the temporary connection and convert it into a permanent connection; E. In the bridge deck patching stage, patch the precast highway bridge deck 40 to complete the construction of the highway bridge deck system.

[0016] The permanent connection in step A is specifically as follows: First, when the steel truss girder 10 is assembled in segments, n + 1 continuous standard bays 20 are formed; Then, the first n standard bays 20 form a continuous bay 21; Finally, the highway longitudinal girders 15 and highway cross girders 16 in the continuous bay 21 are permanently connected.

[0017] The temporary connection in Step A is as follows: First, when the steel truss girder 10 is assembled in segments, n + 1 consecutive standard bays 20 are formed; Then, the (n + 1)-th standard bay 20 is a discontinuous bay 22; Finally, the highway longitudinal girders 15 and highway cross girders 16 in the discontinuous bay 22 are temporarily connected by temporary cleats 30 that allow longitudinal sliding.

[0018] The continuous bays 21 and discontinuous bays 22 form a periodic structure of n continuous and 1 discontinuous.

[0019] In Step B during the incremental launching construction stage, the temporary connection structure does not restrict the longitudinal relative displacement, which is as follows: First, the overall incremental launching operation of the steel truss girder 10 is carried out; Then, during the incremental launching operation, the temporary cleats 30 do not restrict the longitudinal relative displacement between the highway longitudinal girders 15 and highway cross girders 16.

[0020] In Step C during the deformation coordination stage, the deformation coordination between the highway longitudinal girders 15 and the upper chord members 11 of the main truss is carried out, which is as follows: First, after the operation is in place, the precast highway bridge deck 40 is laid in the continuous bay 21 using a bridging machine 50; Then, the self-weight of the precast highway bridge deck 40 is used to promote the deformation coordination between the highway longitudinal girders 15 and the upper chord members 11 of the main truss.

[0021] In Step D during the structural consolidation stage, the temporary connection is removed and converted into a permanent connection, which is as follows: First, after the deformation in Step C is stable, the temporary cleats 30 in the discontinuous bay 22 are removed; Then, the permanent connection of the discontinuous bay 22 is completed.

[0022] In Step E during the bridge deck patching stage, the precast highway bridge deck 40 is patched to complete the construction of the highway bridge deck system, which is as follows: The precast highway bridge deck 40 is patched at the position of the consolidated discontinuous bay 22 using a bridging machine 50 to complete the construction of the highway bridge deck system.

[0023] Specifically, for the permanent connection of the n continuous bays 21 in Step A, according to the stress level of the highway cross girders 16 of the steel truss girder 10 meeting the specification requirements in the final operating state, n = 1, 2, 3, 4... is determined.

[0024] Specifically, the temporary connection by the temporary cleats 30 in Step A is as follows: First, the temporary bridging plate 30 is made of steel structure and is applied in the connection between the highway longitudinal beam 15 and the highway cross beam 16; Then, the temporary bridging plate 30 temporarily connects the longitudinal free end of the highway longitudinal beam 15 with the highway cross beam 16; Subsequently, the temporary bridging plate 30 allows the longitudinal free end of the highway longitudinal beam 15 to generate relative displacement with the highway cross beam 16 only along the longitudinal bridge direction, and only restricts the vertical and lateral displacements of the highway longitudinal beam 15; Subsequently, at the temporary connection between the longitudinal free end of the highway longitudinal beam 15 and the highway cross beam 16 by the temporary bridging plate 30, during the incremental launching construction process, the internal force generated by the inconsistent deformation between the highway longitudinal beam 15 and the upper chord member 11 of the main truss will not be transmitted to the highway cross beam 16; Finally, the temporary bridging plate 30 can be conveniently and quickly converted into a permanent connection in the subsequent incremental launching construction stage.

[0025] As an implementation method, as Figure 6 shown, the temporary bridging plate 30 includes a temporary splicing plate 31 and ordinary bolts 32. The temporary splicing plate 31 is connected to the web of the highway longitudinal beam 15. Long oval holes 33 are arranged along the longitudinal bridge direction in the bolt holes of the temporary splicing plate 31 and the web of the highway longitudinal beam 15, and the aperture allows a longitudinal displacement of ±100 mm.

[0026] As an implementation method, as Figure 7 shown, the temporary bridging plate 30 includes a vertical supporting plate 34. At the temporary connection between the highway longitudinal beam 15 and the highway cross beam 16, the vertical supporting plate 34 is welded to the highway cross beam 16, and the top surface of the vertical supporting plate 34 is flush with the bottom surface of the highway longitudinal beam 15 to be installed; the longitudinal free end of the highway longitudinal beam 15 is placed on the vertical supporting plate 34.

[0027] Meanwhile, the horizontal limit clamping plate 35 of the temporary bridging plate 30 is welded. The horizontal limit clamping plate 35 is arranged on both sides of the web of the highway longitudinal beam 15 and is welded to the highway cross beam 16, but not welded to the highway longitudinal beam 15.

[0028] Specifically, when using the bridging machine 50 to lay the precast highway bridge deck 40 of the continuous panel 21 in step C, a temporary passage 50 for transporting the precast highway bridge deck 40 is set up by using the upper chord member 11 of the main truss.

[0029] Specifically, after laying the precast highway bridge deck 40 of the continuous panel 21 in step C, the precast highway bridge deck 40 at the disconnected panel 22 is temporarily placed on the precast highway bridge deck 40 of the already laid continuous panel 21.

[0030] Specifically, in the n - in - one - cut structure of step A, the disconnection between the highway longitudinal beam 15 and the highway cross beam 16 at the disconnected panel 22 is at the process connection weld in the original design.

[0031] Specifically, in step A, the permanent connection is achieved by welding or bolting.

[0032] Specifically, as Figure 8 shown, the steel truss girder 10 includes the main truss upper chord 11, the main truss lower chord 12, the main truss web members 13, the railway deck system 14 located below, and the highway longitudinal beams 15 and highway cross beams 16 located above.

[0033] Specifically, after the jacking erection of the steel truss girder 10 is completed, the in-situ precast highway bridge deck 40 is used for counterweight to make the upper highway longitudinal beams 15 and the main truss upper chords 11 deform coordinately, avoiding the investment of a large number of temporary counterweight facilities.

[0034] The present invention divides the steel truss girder into a combination of n continuous segments and one discontinuous segment, and uses the precast highway bridge deck laid first at the continuous joints to make the highway longitudinal beams and the main truss upper chords deform coordinately, avoiding the investment of temporary counterweight devices, and solving the problems of over-limit stress of the cross beams caused by the construction of the bridge deck, the secondary dead load and the live load.

[0035] The present invention does not need to increase the cross-sectional size of components or set up strengthening structures to meet the design requirements, saves materials, has high economy, improves the construction efficiency through detachable temporary gusset plates, and ensures the project progress.

Claims

1. A construction method for optimizing the initial stress of the upper highway cross beam of a steel truss girder, characterized in that: It includes the following steps: A. In the prefabrication stage of segments, permanent connections and temporary connections are made for the upper highway longitudinal girders (15) and highway cross girders (16) of the steel truss girder (10). B. In the incremental launching construction stage, the temporary connection structure does not restrict the longitudinal relative displacement. C. In the deformation coordination stage, deformation coordination is carried out between the highway longitudinal girders (15) and the upper chord members (11) of the main truss. D. In the structural consolidation stage, the temporary connections are removed and converted into permanent connections. E. In the bridge deck paving supplement stage, precast highway bridge decks (40) are paved to complete the construction of the highway bridge deck system.

2. The construction method for optimizing the initial stress of the upper-layer highway cross beam of a steel truss girder according to claim 1, characterized in that: The permanent connection in step A is as follows: First, when the steel truss girder (10) is assembled in segments, (n + 1) continuous standard bays (20) are formed. Then, the first n standard bays (20) form a continuous bay (21). Finally, the highway longitudinal girders (15) and highway cross girders (16) in the continuous bay (21) are permanently connected.

3. The construction method for optimizing the initial stress of the upper highway cross beam of a steel truss girder according to claim 2, characterized in that: The temporary connection in step A is as follows: First, when the steel truss girder (10) is assembled in segments, (n + 1) continuous standard bays (20) are formed. Then, the (n + 1)-th standard bay (20) is a discontinuous bay (22). Finally, the highway longitudinal girders (15) and highway cross girders (16) in the discontinuous bay (22) are temporarily connected by temporary cleats (30) that allow longitudinal sliding.

4. The construction method for optimizing the initial stress of the upper-layer highway cross beam of the steel truss girder according to claim 3, characterized in that: The continuous bay (21) and the discontinuous bay (22) form a periodic n-connected and 1-disconnected structure.

5. The construction method for optimizing the initial stress of the upper highway cross beam of a steel truss girder according to claim 1, characterized in that: In step B during the incremental launching construction stage, the temporary connection structure does not restrict the longitudinal relative displacement, which is as follows: First, the overall incremental launching operation of the steel truss girder (10) is carried out. Then, during the incremental launching operation, the temporary cleats (30) do not restrict the longitudinal relative displacement between the highway longitudinal girders (15) and the highway cross girders (16).

6. The construction method for optimizing the initial stress of the upper highway cross beam of a steel truss girder according to claim 1, characterized in that: In step C during the deformation coordination stage, deformation coordination is carried out between the highway longitudinal girders (15) and the upper chord members (11) of the main truss, which is as follows: First, after the operation is in place, precast highway bridge decks (40) are laid in the continuous bay (21) using a bridging machine (50). Then, the self-weight of the precast highway bridge decks (40) is used to promote the deformation coordination between the highway longitudinal girders (15) and the upper chord members (11) of the main truss.

7. A construction method for optimizing the initial stress of the upper highway cross beam of a steel truss girder according to claim 1, characterized in that: In step D during the structural consolidation stage, the temporary connections are removed and converted into permanent connections, which is as follows: First, after the deformation in step C is stable, the temporary cleats (30) in the discontinuous bay (22) are removed. Then, the permanent connection of the discontinuous bay (22) is completed.

8. A construction method for optimizing the initial stress of the upper highway cross beam of a steel truss girder according to claim 1, characterized in that: In step E during the bridge deck paving supplement stage, precast highway bridge decks (40) are paved to complete the construction of the highway bridge deck system, which is as follows: Precast highway bridge decks (40) are paved at the position of the consolidated discontinuous bay (22) using a bridging machine (50) to complete the construction of the highway bridge deck system.

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