Construction method of large-span steel bent cap based on steel support

Abstract

The application discloses a kind of long-span steel bent cap construction methods based on steel support, add pier top steel support between portal pier column, first set corbel structure in construction, then install steel support on corbel structure, install steel bent cap after forming frame structure between steel support and pier column, steel bent cap is divided into blocks with steel bent cap stress reverse bending point as boundary to install steel bent cap, finally, pour concrete to consolidate pier top and steel bent cap, form integral force system, through the above structure and construction sequence improvement, superstructure load is borne by steel support and steel bent cap, improve the stress condition of steel bent cap structure, reinforce pier top using steel support, improve the bearing capacity at pier top position, steel support can be used as support to support and position the block structure of steel bent cap during construction process, reduce the construction difficulty and safety risk of pier and pier top when bent cap and bridge are consolidated in traditional construction scheme.

Description

Technical Field

[0001] This invention relates to the field of bridge structure construction technology. More specifically, this invention relates to a construction method for large-span steel cap beams based on steel supports. Background Technology

[0002] Currently, with the increase in traffic volume, more and more existing transportation facilities are unable to meet the traffic demand. Building new elevated bridges on top of existing transportation facilities has become an important solution for three-dimensional reconstruction and expansion. Portal frame structures are often used as the main structure of the new route, and then the superstructure is erected to form the new bridge. Existing urban roads generally have many lanes and are wide. In order to meet the stress requirements of large-span structures and improve construction efficiency, steel cap beams are recommended.

[0003] Large-span cap beams and piers can be connected by either fixed or hinged joints, forming a frame structure with the cap beams, piers, and pile foundations. Due to the large span of the cap beam structure, significant bending moments and rotations are easily generated at the pier connections, especially at the pier tops. Under load, this poses a significant safety risk to the piers. To address this challenge, the current solution is to adopt a construction scheme where the piers and beams are initially hinged, and then fixed after the second phase of paving is completed. This process releases the self-weight of the cap beam and superstructure, as well as the substantial load from the second phase of paving. During the operational period, the piers only need to bear live loads, thus effectively improving the stress conditions of the piers during construction.

[0004] While the construction method of hinged connection followed by consolidation can solve the stress problem of bridge piers to some extent, it also increases construction difficulties, especially in projects involving multiple cap beam structures. Returning to the construction site not only requires overcoming the difficulties of consolidation itself but also necessitates rebuilding the construction platform, resulting in low construction efficiency and increased disruption to existing traffic. Furthermore, during construction using a bridge erecting machine for the cap beam and superstructure, if there is eccentricity between the cap beam support and the hinged support connecting the pier beam, the cap beam carries a certain risk of overturning under the significant load exerted by the bridge erecting machine's outriggers.

[0005] Considering ease of construction and safety, direct consolidation can better meet the requirements. However, the large internal forces and rotation angles generated by direct consolidation pose safety risks to the structure. Therefore, a feasible technical solution is urgently needed to solve various complex problems in the construction of the cap beam. Summary of the Invention

[0006] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0007] Another objective of this invention is to provide a construction method for large-span steel cap beams based on steel supports, so as to solve the technical problems of high construction difficulty and failure to meet structural stress safety requirements of existing technologies for steel cap beams.

[0008] To achieve these objectives and other advantages according to the present invention, a construction method for a large-span steel cap beam based on steel bracing is provided, comprising the following steps:

[0009] S1. Each steel cap beam corresponds to a pair of piers. The upper part of the pier is a composite pier. Steel formwork is set outside the composite pier. Upper and lower corbels are fixed on the steel formwork on the opposite side of the two piers. A pair of upper corbels are set at intervals on each side of the steel formwork. The central axis of the lower corbel and the pair of upper corbels is aligned with the corresponding central axis of the pier.

[0010] S2. Install steel supports between the two piers. The bottom of each end of the steel support is placed on a lower corbel, and the top of each end of the steel support is located between a pair of upper corbels and abuts against the corresponding sides of the upper corbels. The top surface of the steel support is flush with the top surface of the steel formwork. The ends of the steel support are fixedly connected to the corresponding sides of the steel formwork, the lower corbels, and the pair of upper corbels.

[0011] S3. The steel cap beam is divided into multiple segmented structures along its length, with the point of inflection under stress as the boundary. Each segmented structure is hoisted onto the steel support in the installation direction from both ends to the middle. After being adjusted and aligned, it is fixedly connected to the corresponding steel support and upper bracket, and all segmented structures are fixedly connected as one.

[0012] S4. Pour concrete at the top of the steel cap beam to complete the pier-beam consolidation.

[0013] Preferably, in step S3, the steel cap beam is configured with two end blocks and one middle block along its length. First, the end blocks are hoisted to the top of the pier. After rotation, steel supports are used for auxiliary support and adjustment. After alignment, the bottom of the end blocks is welded to the top of the steel supports. Then, the middle block is hoisted between the pair of end blocks. After lowering and adjustment, the bottom of the middle block is welded to the top of the steel supports. The end blocks and the middle block are then welded together to form a complete steel cap beam. Finally, high-strength bolts are used to connect the bottom of the current steel cap beam to the top of the steel supports and the top of the upper bracket at corresponding positions.

[0014] Preferably, in step S2, the steel support is a rectangular box structure, with a top plate on the top surface, a bottom plate on the bottom surface, and web plates on the front and rear sides in the longitudinal direction of the bridge. The top plate and bottom plate extend horizontally outward on the front and rear sides in the longitudinal direction of the bridge to form side plates. The contact positions of the upper bracket, the lower bracket, the steel template, and the steel support are first welded. The bottom plate of the steel support is bolted to the top of the lower bracket. The web plate of the steel support is bolted to the corresponding side of the upper bracket. The side plates outside the top plate of the steel support are fixedly connected to the top surface of the upper bracket by high-strength bolts.

[0015] Preferably, the top surface of the upper bracket is flush with the top surface of the steel template, and a limiting groove is provided downward on the opposite side of the top of the pair of upper brackets. When installing the steel support, the end of the side plate is inserted downward into the limiting groove on the corresponding side, and after installation, the top surface of the side plate is flush with the top surface of the steel template.

[0016] Preferably, anchor bolts are installed on the inner side of the steel formwork of each pier, corresponding to the upper and lower corbels. One end of the anchor bolt passes through the steel formwork and is bolted to the corresponding upper and lower corbels with anchor bolt nuts. The other end of all anchor bolts is bolted to a pre-embedded steel plate. Concrete is poured on the inner side of the steel formwork to anchor the upper corbels to the steel formwork. PBL connectors are used between the inner side of the steel formwork and the concrete. After all welding and bolting between the upper corbels, lower corbels, and steel supports are completed, the anchor bolt nuts are tightened.

[0017] Preferably, the rotation and repositioning of the end blocks is performed through the following steps:

[0018] A1. Determine the final placement of the end blocks and the middle blocks on the steel support and draw the longitudinal bridge boundary line, then hoist the end blocks along the longitudinal bridge direction.

[0019] A2. A rear guide is provided on the side plate of the steel support located in front of the hoisting direction. The rear guide includes a first C-shaped clamp. The upper and lower sides of the first C-shaped clamp are parallel upper and lower plates. The upper and lower plates are provided with mounting holes corresponding to the bolt holes. The inner side of the first C-shaped clamp is a slot. An extension frame is connected to the outer side of the web plate in a direction away from the steel support. The first C-shaped clamp is clamped on the side plate through the slot outside the boundary line of the end segment and is fixed by screwing temporary bolts into the two mounting holes and one bolt hole. The outer end of the extension frame is connected to a first upright in the transverse direction of the side where the end segment is located. The upper end of the first upright is connected to a first rotating sleeve through a vertical bearing. The side boundary of the first rotating sleeve facing the steel support matches the side position of the end segment after it is adjusted in the transverse direction.

[0020] A3. Corresponding to the current installation position of the end segment, a front guide is set at the upper bracket in the diagonal direction of the rear guide. The front guide includes a vertically arranged second C-shaped clamp. The second C-shaped clamp is used to clamp and bolt to the web plate on the outside of the upper bracket. A second upright is connected to the second C-shaped clamp on the outside of the upper bracket in a direction away from the steel support. The upper end of the second upright is connected to a second rotating sleeve through a vertical bearing. The side boundary of the second rotating sleeve facing the steel support matches the side position of the end segment after adjustment along the transverse bridge direction.

[0021] A4. When the rotating body is divided into sections, the first rotating sleeve and the second rotating sleeve are used as the diagonal boundaries of the rotating body for adjustment;

[0022] A5. After the two sides of the end block abut against the first rotating sleeve and the second rotating sleeve respectively, a second rear guide is set on the side opposite to the rear guide in step A2 to complete the limiting of the end block in the longitudinal direction of the bridge. At this time, the hoisting direction is set to the transverse direction of the bridge, and the end block is moved laterally towards the top of the pier until the position meets the boundary line requirements.

[0023] Preferably, the lower plate of the first C-shaped clamp is set as a semi-circular arc plate on the side facing the steel support. In step A5, when installing the second rear guide, the temporary bolt is not screwed in first. The first C-shaped clamp is rotated so that the second rotating sleeve adapts to the corresponding side of the end block in the rotating body and rotates synchronously with the end block rotating body. After the end block completes the coarse adjustment of its position, the mounting hole and the bolt hole on the first C-shaped clamp are aligned, and the temporary bolt is screwed in so that the position of the end block is finely adjusted.

[0024] The present invention has at least the following beneficial effects:

[0025] (1) The construction method of large-span steel cap beam based on steel support of the present invention divides the steel cap beam into sections for construction, which greatly reduces the hoisting tonnage, improves the hoisting difficulty of large-span cap beams, and reduces the construction difficulty.

[0026] (2) The construction method of large-span steel cap beam based on steel support of the present invention sets up steel support. After the steel support and the pier column form a frame structure, the steel support can serve as a support platform for the subsequent construction of steel cap beam, supporting the entire process of block construction, hoisting and positioning of steel cap beam, avoiding the need to build temporary supports under the bridge and affecting existing traffic.

[0027] (3) The construction method of large-span steel cap beam based on steel support of the present invention anchors the upper and lower corbels on the steel formwork at the top of the pier, and integrates them with the steel support and steel cap beam by welding, bolting and other means. This increases the height of the bending members in the structure and improves the bending bearing capacity of the structure. The load of the upper structure is borne by the steel support and the steel cap beam, which improves the stress condition of the cap beam structure.

[0028] (4) The construction method of large-span steel cap beam based on steel support of the present invention significantly reduces the stress on the steel cap beam and increases the bearing capacity at the top of the pier compared with the traditional construction method of large-span cap beam. Therefore, the structural form of steel cap beam and steel support can be further optimized through structural optimization for different practical applications, reducing the consumption of components and improving economy.

[0029] (5) The construction method of large-span steel cap beam based on steel support of the present invention meets the mechanical and construction ease requirements of direct consolidation. By using steel support to reinforce the pier top, the bearing capacity at the pier top position is improved, and the adverse factors such as the rotation angle and displacement of the pier top are reduced. This allows the large-span cap beam structure to still meet the structural bearing capacity requirements under the direct consolidation method, thereby avoiding the construction difficulties and safety risks caused by hinged joints and subsequent consolidation.

[0030] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0031] Figure 1 This is a front view of the steel cap beam installed on the top of the pier according to the present invention;

[0032] Figure 2 This is a three-dimensional structural diagram of the present invention when the steel support is installed;

[0033] Figure 3 This is a side view of the steel support structure of the present invention.

[0034] Figure 4 A side view of the structure of the present invention with the front guide and the rear guide installed;

[0035] Figure 5 This is a top view of the rear guide component of the present invention;

[0036] Figure 6 This is a top view of the front guide component of the present invention;

[0037] The following are the reference numerals in the accompanying drawings: 1. Pier column, 2. Steel formwork, 3. Upper corbel, 4. Lower corbel, 5. Steel support, 6. End segment, 7. Middle segment, 8. Side plate, 9. Limiting groove, 10. Anchor bolt, 11. PBL connector, 12. Rear guide, 13. Front guide, 14. First C-shaped clamp, 15. Extension frame, 16. First upright, 17. First rotating sleeve, 18. Second C-shaped clamp, 19. Second upright, 20. Second rotating sleeve, 21. Temporary bolt, 30. Steel cap beam. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0039] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] like Figure 1-3 As shown, the present invention provides a construction method for large-span steel cap beams based on steel supports, comprising the following steps:

[0041] S1. Each steel cap beam 30 corresponds to a pair of piers 1. The upper part of the pier 1 is a composite pier. A steel formwork 2 is set outside the composite pier. Upper brackets 3 and lower brackets 4 are fixed on the steel formwork 2 on opposite sides of the two piers 1. A pair of upper brackets 3 are set at intervals on each side of the steel formwork 2. The central axis of the lower brackets 4 and the pair of upper brackets 3 are aligned with the corresponding side central axis of the pier 1.

[0042] Pier 1 is a concrete pier at the lower part and a composite pier at the upper part, with the stress inflection point as the boundary. After the concrete pier is constructed, the formwork is erected and the concrete is poured. The composite pier is constructed using an outer steel plate as the formwork. A lower corbel 4 of a certain length is welded to the bottom position of the steel support 5 on the outside of the steel formwork 2. The vertical center line of the side of the steel support 5 is aligned with the vertical center line of the pier 1. Corbels 3 are welded to the front and rear sides of the longitudinal bridge corresponding to the steel support 5. PBL connectors 11 are used between the inside of the steel plate and the concrete. The steel plate of the connector at the steel support 5 is lengthened and the number of steel bars in the connector is increased. A steel plate and anchor rod 10 are pre-embedded on the side of the pier top facing away from the steel support 5. The anchor rod 10 connects the upper corbel 3 and the lower corbel 4 at the steel support 5, so that the upper corbel 3 and the lower corbel 4 are respectively anchored to the outside of the steel formwork 2 of the composite pier.

[0043] S2. Install steel supports 5 between the two pier columns 1. The two ends of the steel supports 5 are supported on the two lower brackets 4. The lower brackets 4 provide vertical support for the steel supports 5. The top of each end of the steel supports 5 is located between a pair of upper brackets 3 and the web of the steel supports 5 is in contact with the corresponding side of the upper brackets 3. The top surface of the steel supports 5 is flush with the top surface of the steel formwork 2. The ends of the steel supports 5 are fixedly connected to the corresponding side of the steel formwork 2, the lower brackets 4, and the pair of upper brackets 3.

[0044] S3. The steel cap beam 30 is divided into multiple segments along its length, with the point of inflection as the boundary. Following the installation direction from both ends to the middle, each segment is hoisted onto the steel support 5 using a bridge erecting machine. After alignment, it is fixedly connected to the corresponding steel support 5 and upper bracket 3, and all segments are fixedly connected as one unit.

[0045] S4. Pour the steel cap beam 30 and the concrete at the top of the pier to complete the pier-beam connection, and then carry out the construction of the superstructure.

[0046] The construction method of the large-span steel cap beam 30 based on steel support 5 of the present invention adds a pier top steel support 5 between the portal pier columns 1. In the construction process, a corbel structure is first set up, and then the steel support 5 is installed on the corbel structure. After the steel support 5 and the pier column 1 form a frame structure, the steel cap beam 30 is installed. Finally, concrete is poured to consolidate the pier top and the steel cap beam 30. The steel support 5 can limit the internal force and rotation angle of the pier top during construction and operation. At the same time, the steel cap beam 30 is installed in sections with the stress inflection point of the steel cap beam 30 as the boundary. The steel support 5 can act as a bracket to support and adjust the section structure of the steel cap beam 30. Through the above structural and construction sequence improvements, the load of the superstructure is jointly borne by the steel support 5 and the steel cap beam 30, which improves the stress condition of the steel cap beam 30 structure. The steel support 5 is used to reinforce the pier top, which improves the bearing capacity at the pier top position and reduces the construction difficulties and safety risks of the pier and pier top when the cap beam is consolidated with the bridge in the traditional construction scheme.

[0047] In another technical solution, such as Figure 1-3 As shown, in step S3, the steel cap beam 30 is configured with two end blocks 6 and one middle block 7 along its length. First, the end blocks 6 are hoisted to the top of the pier. After rotation, steel supports 5 are used for auxiliary support and adjustment. After alignment, the bottom of the end blocks 6 is welded to the top of the steel supports 5. Then, the middle block 7 is hoisted between the pair of end blocks 6. After lowering and adjustment, the bottom of the middle block 7 is welded to the top of the steel supports 5. The end blocks 6 and the middle block 7 are then welded together to form a complete steel cap beam 30. High-strength bolts are then used to connect the bottom of the current steel cap beam 30 to the top of the steel supports 5 and the top of the upper bracket 3 at corresponding positions.

[0048] The segmented steel cap beams 30 are hoisted to the top of the pier using a bridge erecting machine. The steel support 5 serves as a support platform to facilitate the support and adjustment of the segmented structure. First, the end segments 6 of the steel cap beams 30 at the top of the pier are installed, and then the middle segments 7 of the steel cap beams 30 at the mid-span are installed. The bottom plate of the steel cap beams 30 and the top plate of the steel support 5 are welded together first. After the end segments 6 and the middle segments 7 are all installed and welded into a whole, the bottom plate of the steel cap beams 30 and the top plate of the steel support 5 are connected using high-strength bolts. The weight of large-span cap beams is mostly over 200 tons, or even over 300 tons, making hoisting difficult and construction challenging. Segmenting the steel cap beams 30 for construction greatly reduces the hoisting tonnage, improves the hoisting difficulty of large-span cap beams, and also reduces the construction difficulty. The steel support 5 and the steel cap beam 30 are connected in sequence by welding, bolting and other methods to form an integral whole. This increases the height of the bending member and improves the bending bearing capacity of the structure. The load of the upper structure is borne by the steel support 5 and the cap beam, which improves the stress condition of the steel cap beam 30.

[0049] In another technical solution, such as Figure 1-3 As shown, in step S2, the steel support 5 is a rectangular box structure. A top plate is provided on the top surface of the steel support 5, a bottom plate is provided on the bottom surface, and web plates are provided on the front and rear sides in the longitudinal direction of the bridge. The top plate and bottom plate extend horizontally outwards on the front and rear sides in the longitudinal direction to form side plates 8. First, the contact points of the upper bracket 3, the lower bracket 4, the steel template 2, and the steel support 5 are welded together. The bottom plate of the steel support 5 is bolted to the top of the lower bracket 4, and the web plates of the steel support 5 are bolted to the corresponding sides of the upper bracket 3. The side plates 8 outside the top plate of the steel support 5 are fixedly connected to the top surface of the upper bracket 3 using high-strength bolts. The structure of the side plates 8 facilitates welding and bolting between adjacent structures, increases the support area to a certain extent, and expands the operational and adjustment space of the steel cap beam 30.

[0050] In another technical solution, such as Figure 1-3 As shown, the top surface of the upper bracket 3 is flush with the top surface of the steel template 2. A limiting groove 9 is provided downward on the opposite side of the top of the pair of upper brackets 3. When installing the steel support 5, the end of the side plate 8 is inserted downward into the limiting groove 9 on the corresponding side. After installation, the top surface of the side plate 8 is flush with the top surface of the steel template 2.

[0051] By setting the matching structure between the limiting groove 9 and the side plate 8, on the one hand, the steel support 5 can be quickly aligned when it is installed on the upper bracket 3 and the lower bracket 4. On the other hand, the upper bracket 3 can also provide vertical support for the steel support 5, strengthen the structural connection between the steel support 5 and the upper bracket 3 and the lower bracket 4, and enhance the overall structural strength and load-bearing capacity of the connection.

[0052] In another technical solution, such as Figure 1-2As shown, anchor rods 10 are respectively installed on the inner side of the steel formwork 2 of each pier column 1, corresponding to the upper bracket 3 and the lower bracket 4. One end of the anchor rod 10 passes through the steel formwork 2 and is bolted to the corresponding upper bracket 3 and lower bracket 4 with anchor rod 10 nuts. The other end of all anchor rods 10 is bolted to a pre-embedded steel plate. Concrete is poured on the inner side of the steel formwork 2 to anchor the upper bracket 3 to the steel formwork 2. PBL connectors 11 are used between the inner side of the steel formwork 2 and the concrete. After all welding and bolting between the upper bracket 3, the lower bracket 4 and the steel support 5 are completed, the anchor rod 10 nuts are tightened.

[0053] Similarly, welding is used for pre-fixation first. After the steel support 5 is welded and bolted to the corbel structure, the anchor rod 10 nuts are tightened. After the concrete is poured, the anchor rod 10 is internally anchored to the pre-embedded steel plate at the top of the composite pier and externally anchored to the corbel component.

[0054] In another technical solution, such as Figure 1-6 As shown, the rotation and repositioning of the end block 6 is performed through the following steps:

[0055] A1. Determine the final placement of the end block 6 and the middle block 7 on the steel support 5 and draw the longitudinal boundary line of the bridge. Hoist the end block 6 along the longitudinal direction of the bridge.

[0056] End segment 6 is basically moved and hoisted along the longitudinal direction of the bridge, that is, perpendicular to the length direction. Figure 1 The direction is determined, and then the steel support 5 is used as a support platform for temporary placement. The crane lifts the end block 6 and rotates the end block 6 to the transverse direction. At this time, the center of gravity of the end block 6 is still set close to the middle of the steel support 5 to ensure the safety of the rotation. After the end block 6 is finely adjusted to the transverse direction, the crane can be used in conjunction with the jack set in the middle of the steel support 5 to push the end block 6 to the installation position for welding.

[0057] A2. A rear guide 12 is provided on the side plate 8 located in front of the steel support 5 in the hoisting direction. The rear guide 12 includes a first C-shaped clamp 14. The upper and lower sides of the first C-shaped clamp 14 are parallel upper and lower plates. The upper and lower plates are provided with mounting holes corresponding to the bolt holes. The inner side of the first C-shaped clamp 14 is a slot. An extension frame 15 is connected to the outer side of the web plate in a direction away from the steel support 5. The first C-shaped clamp 14 is clamped on the side plate 8 through the slot and located outside the boundary line of the end block 6. It is fixed by screwing temporary bolts 21 into the two mounting holes and one bolt hole. The outer end of the extension frame 15 is connected to a first upright 16 in the transverse direction facing the side of the end block 6. The upper end of the first upright 16 is connected to a first rotating sleeve 17 through a vertical bearing. The side boundary of the first rotating sleeve 17 facing the steel support 5 matches the side position of the end block 6 after adjustment in the transverse direction.

[0058] For ease of explanation, let's use Figure 4 For example, what is being hoisted at this time is... Figure 1 Left end segment 6, end segment 6 longitudinal bridge moves forward in the direction of Figure 4 The direction is from right to left, and end block 6 rotates counterclockwise in the horizontal plane. The front side of end block 6 is... Figure 4 On the left side, the end block 6 is rotated at the front end in the length direction until it contacts the front guide 13 and at the rear end until it contacts the rear guide 12.

[0059] A3. Corresponding to the installation position of the current end block 6, a front guide 13 is provided at the upper bracket 3 diagonally opposite to the rear guide 12. The front guide 13 includes a vertically arranged second C-shaped clamp 18, which is used to clamp and bolt to the web plate on the outer side of the upper bracket 3, i.e. Figure 4 At the position of the right side plate 8 of the upper bracket 3 shown, the second C-shaped clamp 18 is connected to the second upright 19 on the outside of the upper bracket 3 in a direction away from the steel support 5. The upper end of the second upright 19 is connected to the second rotating sleeve 20 through a vertical bearing. The side boundary of the second rotating sleeve 20 facing the steel support 5 matches the side position of the end block 6 after adjustment along the transverse bridge direction.

[0060] A4. When rotating the end segment 6, adjust the rotation using the first rotating sleeve 17 and the second rotating sleeve 20 as the diagonal boundaries of the rotation. Control the rotation speed until the end segment 6 is... Figure 4 The left side of the end block 6 abuts against the first rotating sleeve 17 of the rear guide 12, and the right side of the end block 6 abuts against the second rotating sleeve 20 of the front guide 13.

[0061] A5. After the two sides of the end block 6 abut against the first rotating sleeve 17 and the second rotating sleeve 20 respectively, a second rear guide 12 is set on the side opposite to the rear guide 12 in step A2 to complete the limiting of the end block 6 in the longitudinal direction of the bridge. At this time, the hoisting direction is set to the transverse direction of the bridge, and the end block 6 is moved laterally towards the top of the pier 1 until the position meets the boundary line requirements.

[0062] By using the steel support 5 as the installation platform and setting up front and rear guide components, boundary limiting is performed during the rotation and adjustment of the end block 6. Unlike the traditional method, there is no need to set up platforms on both sides of the steel cap beam 30 to install jacks for pushing and adjusting. This reduces the space required and improves the installation efficiency of the steel cap beam 30.

[0063] In another technical solution, such as Figure 1-6 As shown, the lower plate of the first C-shaped clamp 14 is set as a semi-circular arc plate on the side facing the steel support 5. In step A5, when installing the second rear guide 12, the temporary bolt 21 is not screwed in first. The first C-shaped clamp 14 is rotated so that the second rotating sleeve 20 adapts to the corresponding side of the end block 6 in the rotating body and rotates synchronously with the end block 6. After guiding the end block 6 to complete the coarse adjustment of its position, the mounting hole and the bolt hole on the first C-shaped clamp 14 are aligned, and the temporary bolt 21 is screwed in so that the position of the end block 6 is finely adjusted.

[0064] The front guide 13 and rear guide 12, located diagonally opposite each other, serve as boundary limits for coarse position adjustment during the rotation process. When the long axis of the end block 6 is offset from the central axis of the steel support 5 by a small angle, another rear guide 12 is set up to push the end block 6 according to the fine angle change of the end block 6 until the position is locked and then fixed. After that, the end block 6 only needs to move along the transverse bridge direction. During the movement, the first rotating sleeve 17 and the second rotating sleeve 20 rotate under the action of the vertical bearing to continue to guide the movement of the end block 6.

[0065] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A construction method for large-span steel cap beams based on steel supports, characterized in that, Includes the following steps: S1. Each steel cap beam corresponds to a pair of piers. The upper part of the pier is a composite pier. Steel formwork is installed outside the composite pier. Upper and lower corbels are fixed on the steel formwork on opposite sides of the two piers. A pair of upper corbels are spaced apart on each side of the steel formwork. The central axis of the lower corbel and the pair of upper corbels is aligned with the corresponding side central axis of the pier. The top surface of the upper corbel is flush with the top surface of the steel formwork. A limiting groove is provided downward on the opposite side of the top of the pair of upper corbels. S2. The steel support is a rectangular box structure. A top plate is provided on the top surface of the steel support, a bottom plate is provided on the bottom surface, and web plates are provided on the front and rear sides in the longitudinal direction of the bridge. The top plate and bottom plate extend horizontally outwards on the front and rear sides in the longitudinal direction to form side plates. The steel support is installed between two piers. When installing the steel support, the bottom ends of both ends of the steel support are placed on a lower bracket. The ends of the side plates corresponding to the top plate are inserted downwards into the corresponding limiting grooves. The top ends of both ends of the steel support are located between a pair of upper brackets and abut against the corresponding sides of the upper brackets. The top surface of the support is flush with the top surface of the steel formwork, and the top surface of the side plate corresponding to the top plate is flush with the top surface of the steel formwork. The end of the steel support is fixedly connected to the corresponding side of the steel formwork, the lower bracket, and a pair of upper brackets. First, the contact positions of the upper bracket, the lower bracket, the steel formwork, and the steel support are welded. The bottom plate of the steel support is bolted to the top of the lower bracket. The web plate of the steel support is bolted to the corresponding side of the upper bracket. The side plate outside the top plate of the steel support is fixedly connected to the top surface of the upper bracket with high-strength bolts. S3. The steel cap beam is divided into multiple segmented structures along its length, with the point of inflection as the boundary. Each segmented structure is hoisted onto the steel support in the installation direction from both ends to the middle. A rear guide is installed on the side plate of the steel support in front of the hoisting direction. A front guide is installed at the upper bracket diagonally opposite the rear guide at the installation position of the corresponding end segment. After adjustment and alignment, the segmented structure is fixedly connected to the corresponding steel support and upper bracket, and all segmented structures are fixedly connected as one. S4. Pour concrete at the top of the steel cap beam to complete the pier-beam consolidation.

2. The construction method for large-span steel cap beams based on steel supports as described in claim 1, characterized in that, In step S3, the steel cap beam is divided into two end blocks and one middle block along its length. First, the end blocks are hoisted to the top of the pier. After rotation, steel supports are used for auxiliary support and adjustment. After alignment, the bottom of the end blocks is welded to the top of the steel supports. Then, the middle block is hoisted between the pair of end blocks. After lowering and adjustment, the bottom of the middle block is welded to the top of the steel supports. The end blocks and the middle block are then welded together to form a complete steel cap beam. Finally, high-strength bolts are used to connect the bottom of the current steel cap beam to the top of the steel supports and the top of the upper bracket at corresponding positions.

3. The construction method for large-span steel cap beams based on steel supports as described in claim 2, characterized in that, Anchor bolts are installed on the inner side of the steel formwork of each pier, corresponding to the upper and lower corbels. One end of the anchor bolt passes through the steel formwork and is bolted to the corresponding upper and lower corbels with anchor bolt nuts. The other end of all anchor bolts is bolted to a pre-embedded steel plate. Concrete is poured inside the steel formwork to anchor the upper corbels to the steel formwork. PBL connectors are used between the inner side of the steel formwork and the concrete. After all welding and bolting between the upper corbels, lower corbels, and steel supports are completed, the anchor bolt nuts are tightened.

4. The construction method for large-span steel cap beams based on steel supports as described in claim 2, characterized in that, When rotating and adjusting the end blocks, the following steps are performed: A1. Determine the final placement of the end blocks and the middle blocks on the steel support and draw the longitudinal bridge boundary line, then hoist the end blocks along the longitudinal bridge direction. A2. A rear guide is provided on the side plate of the steel support located in front of the hoisting direction. The rear guide includes a first C-shaped clamp. The upper and lower sides of the first C-shaped clamp are parallel upper and lower plates. Mounting holes are opened on the upper and lower plates corresponding to bolt holes. The inner side of the first C-shaped clamp is a slot. An extension frame is connected to the outer side of the web plate in a direction away from the steel support. The first C-shaped clamp is clamped on the side plate through the slot outside the boundary line of the end block and fixed by screwing temporary bolts into two mounting holes and one bolt hole. The outer end of the extension frame is connected to a first upright in the transverse bridge direction on the side where the end block is located. The upper end of the first upright is connected to a first rotating sleeve through a vertical bearing. The side boundary of the first rotating sleeve facing the steel support matches the side position of the end block after adjustment in the transverse bridge direction. A3. Corresponding to the current installation position of the end segment, a front guide is set at the upper bracket in the diagonal direction of the rear guide. The front guide includes a vertically arranged second C-shaped clamp. The second C-shaped clamp is used to clamp and bolt to the web plate on the outside of the upper bracket. A second upright is connected to the second C-shaped clamp on the outside of the upper bracket in a direction away from the steel support. The upper end of the second upright is connected to a second rotating sleeve through a vertical bearing. The side boundary of the second rotating sleeve facing the steel support matches the side position of the end segment after adjustment along the transverse bridge direction. A4. When the rotating body is divided into sections, the first rotating sleeve and the second rotating sleeve are used as the diagonal boundaries of the rotating body for adjustment; A5. After the two sides of the end block abut against the first rotating sleeve and the second rotating sleeve respectively, a second rear guide is set on the side opposite to the rear guide in step A2 to complete the limiting of the end block in the longitudinal direction of the bridge. At this time, the hoisting direction is set to the transverse direction of the bridge, and the end block is moved laterally towards the top of the pier until the position meets the boundary line requirements.

5. The construction method for large-span steel cap beams based on steel supports as described in claim 4, characterized in that, The lower plate of the first C-shaped clamp is set as a semi-circular arc plate on the side facing the steel support. In step A5, when installing the second rear guide, the temporary bolt is not screwed in first. The first C-shaped clamp is rotated so that the second rotating sleeve adapts to the corresponding side of the end block in the rotating body and rotates synchronously with the end block rotating body. After the end block completes the coarse adjustment of its position, the mounting hole and the bolt hole on the first C-shaped clamp are aligned, and the temporary bolt is screwed in so that the position of the end block is finely adjusted.

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