Suspension construction method across viaduct girder

Abstract

The present application provides a kind of across viaduct girder cantilever construction method, builds temporary load-bearing body in the two sides of existing viaduct, hoists second girder, first girder in succession, makes second girder install on the temporary load-bearing body of one side, one end of first girder is installed on the second cantilever section of second girder by prefabricated cantilever mounting frame, the other end of first girder is installed on the temporary load-bearing body of other side, and a certain distance is left with the side of existing viaduct when hoisting, to avoid the interference of hoisting equipment and existing viaduct, the length of second cantilever section is greater than the width of existing viaduct by adding the length of first girder, to solve the problem of insufficient girder length, since the end of first girder extending to the deck of existing viaduct can be fixed to second cantilever section by cantilever mounting frame, and the design of construction platform, side widening section construction platform by cross beam, to avoid setting temporary support on viaduct deck, avoid the influence on traffic.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge construction, in particular to a method for constructing a main beam of a bridge spanning over an existing bridge. BACKGROUND

[0002] With the development of cities, the existing roads have been difficult to meet the increasing traffic flow, and erecting viaducts on the existing roads is an effective method to relieve traffic pressure; the steel box girder used in the construction of the existing viaducts is a common structure form of long-span bridges, and the steel box girder has the advantages of small weight, high strength, and convenient construction.

[0003] As shown in Figure 1 The existing viaduct A is a viaduct that has been put into use, and according to the city planning, a new viaduct B needs to be erected across the existing viaduct A; the viaduct B is assembled by a plurality of steel box girders, and when the width of the existing viaduct A is greater than the length of the steel box girder, the steel box girder above the road surface of the existing viaduct A is difficult to assemble, and the construction difficulty is specifically as follows: since the existing viaduct A has been put into use, if a temporary support for supporting the steel box girder is erected on the road surface of the existing viaduct A, and the steel box girder is assembled on the temporary support, the use of the road A will be affected, and the construction and removal of the temporary support will consume manpower and resources; if a hoisting device is used to hoist the steel box girder above the existing viaduct A for assembly, the hoisting arm of the hoisting device will be interfered by the two side walls of the existing viaduct A, so that the hoisting device is difficult to hoist the steel box girder into place.

[0004] How to use the steel box girder to complete the construction of the new viaduct without affecting the use of the existing viaduct when the width of the existing viaduct is greater than the length of the steel box girder is a problem that needs to be solved by the bridge construction department. SUMMARY

[0005] The present application solves the problem of providing a construction method for using the steel box girder to complete the construction of the new viaduct without affecting the use of the existing viaduct when the width of the existing viaduct is greater than the length of the steel box girder.

[0006] The technical scheme adopted by the present application to solve the above problem is: a method for constructing a main beam of a bridge spanning over an existing bridge, comprising the following steps:

[0007] S1: constructing a temporary load-bearing body for supporting the main beam on both sides of the existing bridge;

[0008] S2: using a steel box girder to precast a first main beam and a second main beam for spanning over the existing bridge, a suspension assembly mounting frame, and a code plate; the rear section of the suspension assembly mounting frame is fixed to the main beam top plate at one end of the first main beam, and the front section extends from one end of the first main beam;

[0009] S3: hoist the second main beam to be fixed on the temporary load-bearing body on one side of the viaduct, and make one end of the second main beam extend above the existing viaduct deck to form a second cantilevered segment;

[0010] S4: hoist the first main beam, and make one end of the first main beam be erected on the second cantilevered segment through the front segment of the cantilevered erection frame, and the other end be erected on the temporary load-bearing body on the other side of the viaduct; fix and connect the front segment of the cantilevered erection frame and the second cantilevered segment; fix and connect the other end of the first main beam and the temporary load-bearing body on the other side of the viaduct;

[0011] S5: fix and connect the code plate at the joint between the main beam top plate of the first main beam and the main beam top plate of the second main beam; fix and connect the code plate at the joint between the main beam web plate of the first main beam and the main beam web plate of the second main beam;

[0012] S6: repeat steps S1-S5 along the length direction of the existing viaduct to make multiple main beams be arranged on the viaduct at intervals;

[0013] S7: multiple cross beams are arranged at intervals along the length direction of the main beam between every two main beams;

[0014] S8: a cross beam reinforced construction platform is arranged below the two main beams; the construction personnel stand on the cross beam reinforced construction platform to reinforce the connection between the main beam and the cross beam from below;

[0015] S9: a side widening segment construction platform is erected on the main beam side plate of the outermost main beam;

[0016] S10: hoist the widening segments to be arranged on both sides of the main beam side plate of the outermost main beam, and make the widening inner side plate of the widening segment be attached to the main beam side plate;

[0017] S11: the construction personnel stand on the main beam top plate to fix the upper edge of the widening inner side plate and the main beam top plate; the construction personnel stand on the widening segment construction platform to fix the lower edge of the widening inner side plate and the main beam side plate.

[0018] Compared with the prior art, the present application builds temporary bearing bodies on both sides of the existing viaduct, and hoists the second main beam and the first main beam in sequence through hoisting equipment, so that the second main beam is installed on the temporary bearing body on one side, one end of the first main beam is installed on the second cantilever section of the second main beam through the prefabricated cantilever installation frame, and the other end of the first main beam is installed on the temporary bearing body on the other side. Since the second main beam and the first main beam are hoisted on the outside of the existing viaduct, a certain distance is left from the side of the existing viaduct, thereby avoiding the interference of the hoisting equipment with the existing viaduct. Since one end of the second main beam extends above the bridge deck of the existing viaduct to form the second cantilever section, the length of the second cantilever section plus the length of the first main beam is greater than the width of the existing viaduct, thereby solving the problem of insufficient length of the main beam. Since the end of the first main beam extending to the bridge deck of the existing viaduct can be fixed to the second cantilever section through the cantilever installation frame, the temporary support on the viaduct deck is avoided, and the impact on traffic is avoided.

[0019] The present application fixes the connecting plate at the joint of the first main beam and the second main beam, cooperates with the cantilever installation frame, and provides temporary support force for the first main beam and the second main beam together, so as to prevent the cantilever installation frame from falling to the existing viaduct deck due to insufficient support force, and to ensure the safety of subsequent construction. The present application sets the cross beam reinforcing construction platform below the two main beams, so that the construction personnel can stand on the cross beam reinforcing construction platform to perform the construction of the cross beam, thereby avoiding the temporary support for the cross beam construction on the existing viaduct, and avoiding the impact on traffic. The present application is provided with the side widening section construction platform, so that the construction personnel can stand on the side widening section construction platform to perform the construction of the lower edge of the widening section, thereby avoiding the temporary support for the widening section construction on the existing viaduct, and avoiding the impact on traffic.

[0020] In the present application, the number of the cantilever installation frames is two, and the two cantilever installation frames are arranged on both sides of the main beam top plate of the first main beam. Through the design of the two cantilever installation frames, the gravity of the first main beam is shared together, and the two cantilever installation frames are arranged on both sides of the main beam top plate of the first main beam, so that the force balance on both sides is achieved, and the first main beam is not easy to overturn.

[0021] In the present application, the cantilever installation frame comprises a T-shaped plate. The T-shaped plate comprises a horizontal plate and a vertical plate arranged perpendicularly to the horizontal plate. The lower end surface of the vertical plate is fixedly connected to the main beam top plate. The two sides of the vertical plate are each provided with a plurality of muscle plates. The upper end surface of the muscle plate is fixedly connected to the lower end surface of the horizontal plate.

[0022] In the present application, step S4 comprises the following sub-steps:

[0023] S41: hoist the first main beam by using the crane, and the crane is unloaded gradually but not released;

[0024] S42: unload the suspension assembly mounting frame arranged on the main beam top plate of the first main beam on the main beam top plate of the second main beam gradually;

[0025] S43: unload the other end of the first main beam on the temporary load-bearing body on the other side of the viaduct gradually;

[0026] S44: after the crane is completely unloaded, weld the suspension assembly mounting frame on the main beam top plate of the second main beam, and fix the other end of the first main beam and the temporary load-bearing body on the other side of the viaduct;

[0027] S45: release the hook of the crane.

[0028] Through the step S4 construction, the crane is unloaded gradually but not released, the safety of the first main beam is ensured, and the situation that the first main beam is caused to fall off due to insufficient support force of the suspension assembly mounting frame or the temporary load-bearing body on the other side of the viaduct is prevented; after the crane is completely unloaded, welding construction is carried out again, so that the position of the welding seam is ensured to be in a stress-free state; after all the fastening measures are completely installed, the hook is released, so that the reliability of the temporary reinforcement is ensured.

[0029] The suspension assembly construction method for crossing the main beam of the viaduct of the application, in step S5: the code plate comprises a plurality of reinforced code plates; a plurality of ordinary code plates are arranged between every two reinforced code plates; the reinforced code plates and the ordinary code plates are fixed by welding; through the arrangement of the two different code plates, the splicing of the second main beam and the first main beam is further strengthened in cooperation with the suspension assembly mounting frame.

[0030] The suspension assembly construction method for crossing the main beam of the viaduct of the application, in step S8: the cross beam reinforcement construction platform comprises a plurality of profile steel strips, and one fastener is arranged at the two ends of each profile steel strip; the profile steel strips are fixedly connected to the lower end surfaces of the main beams on the two sides of the cross beam to be reinforced through the fasteners arranged at the two ends; a profiled steel plate is arranged on the upper end surfaces of the plurality of profile steel strips; through the design that the profiled steel plate is arranged on the plurality of profile steel strips, the cross beam reinforcement construction platform has the advantages of simple disassembly and assembly, light weight and high strength.

[0031] The cross-bridge main beam suspension construction method of the application, in step S9: the widening section construction platform comprises a lateral bracing, one end of the lateral bracing is fixedly connected to the main beam side plate; the other end of the lateral bracing is provided with a protective strip; the protective strip is vertically arranged with the lateral bracing; a support strip is arranged below the lateral bracing in an inclined manner; one end of the support strip is fixedly connected to the end of the lateral bracing away from the main beam side plate, and the other end is fixedly connected to the main beam side plate; a groove is arranged on the side of the lateral bracing close to the main beam side plate; a plurality of the lateral bracings are provided with profiled steel plates; the lower section of a plurality of the protective strips is provided with a profiled steel plate, and the upper section is provided with a protective net; through the design of the profiled steel plates arranged on the plurality of lateral bracings, the widening section construction platform has the advantages of simple disassembly and assembly, light weight and high strength; through the design of the protective strip, the outer side of the widening section construction platform has safety guarantee; through the design of the support strip, the connection between the widening section construction platform and the main beam side plate is more firm, and has better load bearing performance; through the design of the groove, the operator has more operation space, so as to facilitate the fixation of the lower edge and the main beam side plate.

[0032] The cross-bridge main beam suspension construction method of the application, wherein the profiled steel plate comprises a plurality of upward protruding support parts; a groove is arranged between every two support parts; the profiled steel plate is bent or curled through the groove; through the shape design of the profiled steel plate, the profiled steel plate has the advantages of light weight, high strength and easy transportation. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a construction road condition schematic diagram of the application;

[0034] Figure 2 It is an end view of the newly-built elevated bridge;

[0035] Figure 3 It is a sectional view of the main beam;

[0036] Figure 4 It is an enlarged view of the widening section construction platform;

[0037] Figure 5 It is an enlarged view of the cross beam reinforcing construction platform;

[0038] Figure 6 It is an enlarged view of the connection structure of the first main beam and the second main beam;

[0039] Figure 7 It is a side view of the suspension installation frame;

[0040] Figure 8 It is a structure schematic diagram of the profiled steel plate;

[0041] Figure 9 It is a structure schematic diagram of the temporary load bearing body;

[0042] Figure 10 Fig. 1 is a structural schematic diagram of a concrete deck foundation. DETAILED DESCRIPTION

[0043] Before any embodiments of the application are explained in detail, it is to be understood that the application is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The application is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings.

[0044] Also, in the disclosure of the present application, the terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore the above terms cannot be understood as limiting the present application. In the second aspect, the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of one element can be one, and in another embodiment, the number of the element can be multiple, and the term "one" cannot be understood as limiting the number.

[0045] It should be understood by those skilled in the art that the embodiments of the present application described above and shown in the drawings are only examples and do not limit the present application. The purpose of the present application has been fully and effectively achieved. The function and structural principle of the present application has been shown and described in the embodiments, and the embodiments of the present application can have any modification or modification without departing from the said principle.

[0046] The embodiments of the present application will be further described below with reference to the accompanying drawings.

[0047] Please refer to Figures 1-8 A method for constructing a main beam of an elevated bridge by cantilevering, comprising the following steps:

[0048] S1: Build a temporary load-bearing body 2 for supporting the main beam 1 on both sides of the existing elevated bridge;

[0049] S2: using steel box girder prefabricated for the first main beam 1a, the second main beam 1b, the prefabricated cantilever erection frame 3 and the code plate 8 for crossing the existing viaduct; the rear section of the cantilever erection frame 3 is fixed on the main beam top plate 11 at one end of the first main beam 1a, and the front section extends from one end of the first main beam 1a;

[0050] S3: hoisting the second main beam 1b to be fixed on the temporary load-bearing body 2 on one side of the viaduct, and making one end of the second main beam 1b extend above the existing viaduct deck to form a second cantilever section;

[0051] S4: hoisting the first main beam 1a, making one end of the first main beam 1a erected on the second cantilever section through the front section of the cantilever erection frame 3, and the other end erected on the temporary load-bearing body 2 on the other side of the viaduct; fixing and connecting the front section of the cantilever erection frame 3 with the second cantilever section; fixing and connecting the other end of the first main beam 1a with the temporary load-bearing body 2 on the other side of the viaduct;

[0052] S5: fixing and connecting the code plate 8 at the joint between the main beam top plate 11 of the first main beam 1a and the main beam top plate 11 of the second main beam 1b; fixing and connecting the code plate 8 at the joint between the main beam web plate 13 of the first main beam 1a and the main beam web plate 13 of the second main beam 1b;

[0053] S6: repeating steps S1-S5 along the length direction of the existing viaduct to arrange multiple main beams 1 on the viaduct at intervals;

[0054] S7: arranging multiple cross beams 4 at intervals along the length direction of the main beam 1 between every two main beams 1;

[0055] S8: arranging a cross beam reinforcing construction platform 5 below the two main beams 1; construction workers stand on the cross beam reinforcing construction platform 5 to reinforce the connection between the main beam 1 and the cross beam 4 from below;

[0056] S9: erecting a side widening section construction platform 6 on the main beam side plate 12 of the outermost main beam 1;

[0057] S10: hoisting the widening section 7 respectively to the two sides of the main beam side plate 12 of the outermost main beam 1, and making the widening inner side plate 71 of the widening section 7 fit with the main beam side plate 12;

[0058] S11: construction workers stand on the main beam top plate 11 to fix the upper edge 711 of the widening inner side plate 71 with the main beam top plate 11; construction workers stand on the widening section construction platform 6 to fix the lower edge 712 of the widening inner side plate 71 with the main beam side plate 12.

[0059] In actual construction, the temporary load-bearing body 2 is built on both sides of the existing viaduct, and the second main beam 1b and the first main beam 1a are hoisted in sequence by hoisting equipment, so that the second main beam 1b is installed on the temporary load-bearing body 2 on one side, one end of the first main beam 1a is installed on the second cantilever section of the second main beam 1b through the prefabricated cantilever installation frame 3, and the other end of the first main beam 1a is installed on the temporary load-bearing body 2 on the other side. Please refer to Figure 1 Since the second main beam 1b and the first main beam 1a are hoisted on the outside of the existing viaduct, a certain distance is left from the side of the existing viaduct, the hoisting equipment does not need to hoist the main beam 1 to the center of the existing viaduct, and therefore the hoisting arm of the hoisting equipment can be pulled away from the side of the existing viaduct, thereby avoiding the interference between the hoisting equipment and the existing viaduct. Since one end of the second main beam 1b extends to above the bridge deck of the existing viaduct to form the second cantilever section, the length of the second cantilever section plus the length of the first main beam 1a is greater than the width of the existing viaduct, thereby solving the problem of insufficient length of the main beam. Since one end of the first main beam 1a extending to the bridge deck of the existing viaduct can be fixed to the second cantilever section through the cantilever installation frame 3, the temporary support on the bridge deck of the existing viaduct is avoided, and the impact on traffic is avoided.

[0060] After the splicing of the second main beam 1b and the first main beam 1a is completed, the connecting code plate 8 is fixed and connected at the joint of the first main beam 1a and the second main beam 1b, and cooperates with the cantilever installation frame 3 to provide temporary support force for the first main beam 1a and the second main beam 1b, so as to prevent the first main beam 1a and the second main beam 1b from falling to the existing viaduct due to insufficient support force of the cantilever installation frame 3, and to facilitate the safe construction of subsequent construction. The cross beam reinforcing construction platform 5 is arranged below the two main beams 1, so that the construction personnel can stand on the cross beam reinforcing construction platform 5 to perform the construction of the cross beam 4, the temporary support for the construction of the cross beam 4 on the existing viaduct is avoided, and the impact on traffic is avoided. The side widening section construction platform 6 is arranged, so that the construction personnel can stand on the side widening section construction platform 6 to perform the construction of the lower edge 712 of the widening section 7, the temporary support for the construction of the widening section 7 on the existing viaduct is avoided, and the impact on traffic is avoided.

[0061] It is worth mentioning that, as shown in Figure 9 In some embodiments, the temporary load-bearing body 2 is composed of four lattice columns, and a distribution beam for bearing the main beam 1 is fixed and connected to the upper end surface of the plurality of lattice columns. A concrete pier foundation is arranged below each lattice column to ensure stable support of the main beam 1.

[0062] As shown in Figure 10As shown, specifically, the lattice column is composed of 4 vertical column steel pipes, and the 4 vertical column steel pipes are provided with web members for increasing stability and strength; the concrete strength of the concrete pile cap foundation is not less than C30, the concrete pile cap foundation is provided with a steel mesh, and the upper portion of the concrete pile cap foundation is provided with a pre-embedded part, and the column foot of the vertical column steel pipe is welded with the pre-embedded part, so as to ensure the strength of the temporary load-bearing body 2.

[0063] Please continue to refer to Figure 2 In step S2, the number of the cantilever assembly frame 3 is two, and the cantilever assembly frame 3 is arranged on both sides of the girder top plate 11 of the first main girder 1a; through the design of the two cantilever assembly frames 3, the gravity of the first main girder 1a is shared, and the two cantilever assembly frames 3 are arranged on both sides of the girder top plate 11 of the first main girder 1a, so that the first main girder 1a is balanced on both sides and is not easy to overturn.

[0064] Please continue to refer to Figure 7 The cantilever assembly frame 3 comprises a T-shaped plate 31; the T-shaped plate 31 comprises a horizontal plate 311 and a vertical plate 312 arranged perpendicularly to the horizontal plate 311; the lower end surface of the vertical plate 312 is fixedly connected to the girder top plate 11; the two sides of the vertical plate 312 are provided with a plurality of rib plates 313; the upper end surface of the rib plate 313 is fixedly connected to the lower end surface of the horizontal plate 311.

[0065] When the prefabricated cantilever assembly frame 3 is assembled, the cantilever assembly frame 3 is welded by the horizontal plate 311, the vertical plate 312 and the plurality of rib plates 313 distributed along the two sides of the vertical plate 312, so that the cantilever assembly frame 3 has the advantages of saving materials and light weight.

[0066] Please further refer to Figure 7 Specifically, the shape of the rib plate 313 is trapezoidal, the rib plate 313 comprises an upper base and a lower base, and the length of the upper base is less than the length of the lower base; the upper base is welded with the lower base of the horizontal plate 311, and the lower base is welded with the girder top plate 11; since the contact area of the lower base is larger, the stability of the cantilever assembly frame 3 relative to the girder top plate 11 is better.

[0067] Please continue to refer to Figure 1 , Figure 7 The step S4 comprises the following sub-steps:

[0068] S41: using a crane to hoist the first main girder 1a, and the crane gradually unloads but does not loosen the hook;

[0069] S42: gradually unloading the cantilever assembly frame 3 arranged on the girder top plate 11 of the first main girder 1a on the girder top plate 11 of the second main girder 1b;

[0070] S43: gradually unloading the other end of the first main girder 1a on the temporary load-bearing body 2 on the other side of the viaduct;

[0071] S44: After the crane is completely unloaded, the suspension installation frame 3 on the top plate 11 of the second main beam 1b is welded, and the other end of the first main beam 1a is fixed to the temporary load-bearing body 2 on the other side of the viaduct;

[0072] S45: The crane is loosened.

[0073] Through the construction of step S4, the crane is gradually unloaded but not loosened, which ensures the safety of the unloading of the first main beam 1a and prevents the first main beam 1a from falling off due to insufficient support force of the suspension installation frame 3 or the temporary load-bearing body 2 on the other side of the viaduct; after the crane is completely unloaded, welding construction is carried out again to ensure that the welding position is in a stress-free state; after all the fastening measures are completely installed, the loosening is carried out to ensure the reliability of the temporary reinforcement.

[0074] It is worth mentioning that the material of the suspension installation frame 3 is preferably Q345B, and the suspension installation frame 3 and the top plate 11 of the main beam are welded by full welding of the fillet weld, and preferably, the height of the welding angle is 18mm.

[0075] Please continue to refer to Figure 3 , Figure 6 , wherein in step S5: the code plate 8 includes a plurality of reinforced code plates 81; a plurality of ordinary code plates 82 are arranged between every two reinforced code plates 81; and the reinforced code plates 81 and the ordinary code plates 82 are fixed by welding.

[0076] Specifically, the reinforced code plates 81 and the ordinary code plates 82 are rectangular steel plates of different specifications; the material of the reinforced code plates 81 is preferably Q345B, and the reinforced code plates 81 are arranged uniformly on the top plate 11 and the web plate 13 of the main beam, and preferably, 2-4 reinforced code plates 81 are arranged on one surface; and the welding mode of the reinforced code plates 81 and the top plate 11 or the web plate 13 of the main beam is preferably open groove welding; the specification of the ordinary code plates 82 is smaller than that of the reinforced code plates 81, and the ordinary code plates 82 are arranged at intervals between the reinforced code plates 81; and the welding mode of the ordinary code plates 82 is preferably single-sided fillet weld welding; through the arrangement of the two different code plates 8, the splicing of the second main beam 1b and the first main beam 1a is further strengthened in cooperation with the suspension installation frame 3.

[0077] Please refer to Figure 2 , Figure 5 , in step S8: the cross beam reinforcement construction platform 5 includes a plurality of steel bars 51, each end of each steel bar 51 is provided with a fastener 52; the steel bar 51 is fixedly connected to the lower end surface of the main beam 1 on both sides of the cross beam 4 to be reinforced through the fastener 52 arranged at both ends; the upper end surface of the plurality of steel bars 51 is paved with a pressure steel plate 9; through the design of paving the pressure steel plate 9 on the plurality of steel bars 51, the cross beam reinforcement construction platform 5 has the advantages of simple disassembly and assembly, light weight and high strength.

[0078] It is worth mentioning that when the prefabricated main beam 1, the connecting structure can be prefabricated at the position where the fastener 52 needs to be connected; when the main beam 1 is erected, the construction personnel can set the fastener 52 on the connecting structure mechanism, and then set the profiled steel strip 51 and the profiled steel plate 9.

[0079] Please continue to refer to Figure 2 、 Figure 4 In step S9: the widening section construction platform 6 includes a lateral bracing 61, one end of which is fixedly connected to the main beam side plate 12; the other end of the lateral bracing 61 is provided with a protective strip 62; the protective strip 62 is vertically arranged with the lateral bracing 61; the lateral bracing 61 is provided with a support strip 63 below and is inclined; one end of the support strip 63 is fixedly connected to the end of the lateral bracing 61 away from the main beam side plate 12, and the other end is fixedly connected to the main beam side plate 12; the side of the lateral bracing 61 close to the main beam side plate 12 is provided with a groove 611; a plurality of lateral bracings 61 are laid with profiled steel plates 9; the lower section of a plurality of protective strips 62 is laid with profiled steel plates 9, and the upper section is laid with protective nets; through the design of laying profiled steel plates 9 on a plurality of lateral bracings 61, the widening section construction platform 6 has the advantages of simple disassembly and assembly, light weight and high strength; through the design of the protective strip 62, the outer side of the widening section construction platform 6 has safety protection; through the design of the support strip 63, the connection between the widening section construction platform 6 and the main beam side plate 12 is more firm, and has better load bearing performance; through the design of the groove 611, the construction personnel have more operating space for the fixation of the lower edge 712 and the main beam side plate 12.

[0080] It is worth mentioning that in combination with the actual working conditions, such as the convenience of prefabrication, transportation and hoisting, and the size of the main beam 1 and the existing elevated bridge surface, the widening section construction platform 6 can also be prefabricated on the outermost main beam 1 in step S2; if the prefabrication conditions are met and the widening section construction platform 6 is prefabricated in advance, it is not necessary to repeatedly erect after the main beam 1 is erected, which is conducive to reducing the construction difficulty.

[0081] The cross-elevated bridge main beam cantilever construction method of the application, wherein the profiled steel plate 9 includes a plurality of upward protruding support portions 91; a groove 92 is arranged between every two support portions 91; the profiled steel plate 9 is bent or curled through the groove 92; through the shape design of the profiled steel plate 9, it has the advantages of light weight, high strength and easy transportation.

[0082] The above only describes the best embodiments of the application, but cannot be understood as a limitation on the claims. The application is not limited to the above embodiments, and the specific structure can be changed. Any changes made within the protection scope of the independent claims of the application are within the protection scope of the application.

Claims

1. A method for constructing a bridge deck over a main beam of a viaduct, characterized in that The method comprises the following steps: S1: constructing temporary load-bearing bodies (2) on both sides of the existing viaduct for supporting the main beams (1); S2: prefabricating the first main beam (1a) and the second main beam (1b) for crossing the existing viaduct, the prefabricated cantilever erection frame (3) and the code plate (8) by using steel box beams; the rear section of the cantilever erection frame (3) is fixed on the main beam top plate (11) at one end of the first main beam (1a), and the front section extends from one end of the first main beam (1a); S3: hoisting the second main beam (1b) to be fixed on the temporary load-bearing body (2) at one side of the viaduct, and extending one end of the second main beam (1b) above the existing viaduct deck to form a second cantilever section; S4: hoisting the first main beam (1a) to be erected on the second cantilever section through the front section of the cantilever erection frame (3) at one end, and on the temporary load-bearing body (2) at the other side of the viaduct at the other end; fixing and connecting the front section of the cantilever erection frame (3) with the second cantilever section; fixing and connecting the other end of the first main beam (1a) with the temporary load-bearing body (2) at the other side of the viaduct; S5: fixing and connecting the code plate (8) at the joint between the main beam top plate (11) of the first main beam (1a) and the main beam top plate (11) of the second main beam (1b); fixing and connecting the code plate (8) at the joint between the main beam web (13) of the first main beam (1a) and the main beam web (13) of the second main beam (1b); S6: repeating steps S1-S5 along the length direction of the existing viaduct to arrange multiple main beams (1) on the viaduct at intervals; S7: arranging multiple cross beams (4) at intervals along the length direction of the main beam (1) between every two main beams (1); S8: arranging the cross beam reinforcing construction platform (5) below the two main beams (1); the construction personnel stand on the cross beam reinforcing construction platform (5) to reinforce the connection between the main beam (1) and the cross beam (4) from below; S9: erecting the side widening section construction platform (6) on the main beam side plate (12) of the outermost main beam (1); S10: hoisting the widening section (7) to be arranged on both sides of the main beam side plate (12) of the outermost main beam (1), and making the widening inner side plate (71) of the widening section (7) fit the main beam side plate (12); In step S8: the cross beam reinforcing construction platform (5) comprises multiple steel bars (51), and each steel bar (51) is provided with a fastener (52) at both ends; the steel bar (51) is fixed and connected to the lower end surface of the main beam (1) on both sides of the cross beam (4) to be reinforced through the fasteners (52) arranged at both ends; the upper end surface of the multiple steel bars (51) is paved with a profiled steel plate (9). ​ In step S9: the widening section construction platform (6) comprises a lateral bracing (61), one end of which is fixedly connected to the side plate (12) of the main beam; the other end of the lateral bracing (61) is provided with a protective strip (62); the protective strip (62) is arranged vertically to the lateral bracing (61); a support strip (63) is arranged obliquely below the lateral bracing (61); one end of the support strip (63) is fixedly connected to the end of the lateral bracing (61) away from the side plate (12) of the main beam, and the other end is fixedly connected to the side plate (12) of the main beam; a groove (611) is arranged on the side of the lateral bracing (61) close to the side plate (12) of the main beam; a plurality of the lateral bracings (61) are laid with profiled steel plates (9); the lower sections of a plurality of the protective strips (62) are laid with profiled steel plates (9), and the upper sections are laid with protective nets.

2. The method according to claim 1, wherein, In step S2: the number of the cantilever installation frames (3) is two, and they are arranged on both sides of the main beam top plate (11) of the first main beam (1a).

3. The method according to claim 2, wherein: The cantilever installation frame (3) comprises a T-shaped plate (31); the T-shaped plate (31) comprises a horizontal plate (311) and a vertical plate (312) arranged vertically to the horizontal plate (311); the lower end surface of the vertical plate (312) is fixedly connected to the main beam top plate (11); a plurality of rib plates (313) are arranged on both sides of the vertical plate (312); the upper end surface of the rib plate (313) is fixedly connected to the lower end surface of the horizontal plate (311).

4. The method of claim 3, wherein Step S4 comprises the following sub-steps: S41: use the crane to hoist the first main beam (1a), and the crane gradually unloads but does not release the hook; S42: gradually unload the cantilever installation frame (3) arranged on the main beam top plate (11) of the first main beam (1a) on the main beam top plate (11) of the second main beam (1b); S43: gradually unload the other end of the first main beam (1a) on the temporary load-bearing body (2) on the other side of the viaduct; S44: after the crane is completely unloaded, weld the cantilever installation frame (3) on the main beam top plate (11) of the second main beam (1b), and fix the other end of the first main beam (1a) and the temporary load-bearing body (2) on the other side of the viaduct; S45: release the hook of the crane.

5. The method of cantilever construction across a viaduct girder as claimed in claim 1, wherein, In step S5: the code plate (8) comprises a plurality of reinforced code plates (81); a plurality of ordinary code plates (82) are arranged between every two reinforced code plates (81); the reinforced code plates (81) and the ordinary code plates (82) are fixed by welding.

6. The method of cantilever construction across viaduct girder according to claim 1, characterized in that: The profiled steel plate (9) comprises a plurality of upwardly protruding support portions (91); a groove (92) is arranged between every two support portions (91); the profiled steel plate (9) is bent or curled through the groove (92).

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