A new and old viaduct widening structure and a construction method thereof

Abstract

The application discloses a new and old elevated bridge widening structure, which comprises two groups of steel cover plates, the two groups of steel cover plates are horizontally and symmetrically arranged between flange plates of an old bridge and a new bridge, longitudinal pull shafts for supporting rotation of the two groups of steel cover plates are arranged between the two groups of steel cover plates, and steel bottom dies longitudinally extending at bottom sides of the two groups of steel cover plates are arranged, the steel bottom dies are vertically and penetratingly provided with holding frames extending between the two groups of steel cover plates to connect the steel bottom dies and the steel cover plates. The application has the beneficial effects that the steel bottom dies can be pushed along the length direction of the bridge to drive the holding frames and the closing dies to move, continuous formwork supporting is realized during the widening process of the bridge along the length direction of the bridge, and the widening efficiency of the bridge is improved; meanwhile, the closing dies as grouting dies can be synchronously moved with the steel bottom dies to realize position replacement, the closing dies can be rotated to realize upward turning and downward placing through the holding frames, and the demolding convenience is improved.

Description

Technical Field

[0001] This invention belongs to the field of bridge widening construction technology, specifically relating to a new and old viaduct widening structure and its construction method. Background Technology

[0002] With the continuous development of my country's economy, transportation infrastructure is constantly being improved. Bridges, as a crucial part of transportation infrastructure, are seeing a gradual expansion in both number and scale. In recent years, road surfaces, including bridge decks, have been continuously widened to meet the increasing demands of my country's transportation volume. Bridge widening and splicing are primarily aimed at improving traffic capacity. Existing bridges have become bottlenecks on highways and urgently need widening. Scientific, applicable, and economically sound bridge widening and reconstruction are of great significance for saving investment and creating good social and economic benefits. Currently, there is no reliable and efficient connection model in China for handling the joint problems in the widening and reconstruction of large bridges. Successfully solving these problems has significant scientific and engineering application value for the widespread widening and reconstruction of existing bridges.

[0003] Currently, bridge widening joints mostly use hinged joints, forming hinges by connecting steel bars at the joint. The connection is only at the bridge deck, which can transfer shear force and ensures continuous bridge deck widening. This can solve cracking and misalignment caused by uneven settlement. However, during construction, it is necessary to keep the two sets of steel cover plates, which serve as the hinged structure on both sides, in a hinged state. It is also necessary to separately support and grout the two sets of steel cover plates to the gap between the new and old bridges, which makes formwork difficult. In addition, there are problems with the limited space and high operational difficulty in planting steel bars between the steel cover plates and the bridge body at the joint. Summary of the Invention

[0004] The purpose of this invention is to provide a new structure and construction method for widening an old viaduct in order to solve the above problems. A movable steel bottom formwork is placed along the length of the bridge to move the retaining frame and the composite formwork. Continuous formwork is achieved during the widening process along the length of the bridge, thereby improving the efficiency of bridge widening. Details are described below.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The present invention provides a widening structure for a new and old viaduct, comprising two sets of steel cover plates between the old bridge and the new bridge. The two sets of steel cover plates are symmetrically arranged laterally between the flange plates of the old bridge and the new bridge. A longitudinal tension shaft is provided between the two sets of steel cover plates to support the rotation of the two sets of steel cover plates. A longitudinally extending steel bottom mold is provided on the bottom side of the two sets of steel cover plates. A retainer is vertically inserted on the bottom side of the steel bottom mold and extends between the two sets of steel cover plates to connect the steel bottom mold and the steel cover plates.

[0007] Between the two sets of steel cover plates, there are vertically staggered fixing ears corresponding to the retainer. The retainer vertically penetrates the two sets of fixing ears. A locking block is fixed at the top of the fixing ear. A through hole is vertically penetrating the middle of the fixing ear to accommodate the locking block. A locking groove is provided on the top side of the fixing ear to lock the locking block. The through hole and the locking groove are arranged in a cross shape.

[0008] Preferably, a knob is fixed at the bottom of the retainer, the retainer extends vertically through the steel bottom mold and is fitted with the steel bottom mold with a gap, and a spring is sleeved on the outer side of the bottom of the retainer, with the two ends of the spring abutting against the bottom side of the steel bottom mold and the top side of the knob, respectively, so as to pull the top locking block of the retainer to abut against the inside of the locking groove.

[0009] Preferably, the top side of the steel cover plate extends horizontally to form a horizontal plate, and a vertical plate extending vertically between the old bridge and the new bridge is fixed on one side of the horizontal plate. A receiving groove for accommodating the fixing lugs is longitudinally penetrated on the inner side of the vertical plate. The bottom edge of the receiving groove is bent inward to form a side edge supporting the steel bottom mold. Lateral reinforcing bars extending outward are provided on the inner side of the steel cover plate.

[0010] Preferably, the steel bottom mold includes a bottom plate that abuts against the bottom edge of the steel cover plate. A top frame is provided above the bottom plate, extending longitudinally into the receiving groove between the two sets of steel cover plates. Multiple sets of support rollers are evenly arranged longitudinally on both outer sides of the top frame. The side edge can support the support rollers to drive the steel bottom mold to slide longitudinally. A reinforcing plate supporting the top frame is fixed on the top side of the bottom plate. A grouting mold cavity is formed between the bottom plate and the steel cover plate. A closing template for closing the grouting mold cavity can be opened on both the front and rear sides of the bottom plate.

[0011] Preferably, the base plate has a mold opening seat fixed on both the front and rear sides to support the rotation of the mold assembly formwork. The bottom side of the mold assembly formwork has a support ear that cooperates with the mold opening seat to form a hinge frame. A drum is coaxially fixed on the outside of the retainer below the fixed ear. A mounting groove cavity runs longitudinally through the bottom side of the mold assembly formwork. A traction frame is horizontally fixed inside the mounting groove cavity. A steel cable is wound and fixed on the outside of the drum to pull and drag the traction frame to drive the mold assembly formwork to rotate and open and close as a whole.

[0012] Preferably, the lateral rebar includes a long rebar arranged laterally inside the grouting mold cavity, and a plurality of short rebars arranged vertically and evenly below the long rebar. Each of the long and short rebars is fixed with a connecting shaft at one end near the steel cover plate. The outer side of the steel cover plate is provided with a rebar connecting lug that is hinged to the connecting shaft to support the rotation of the long and short rebars.

[0013] Preferably, both the long and short reinforcing bars are fixed with lifting lugs on their outer sides, and a suspension bar is vertically connected between two adjacent sets of lifting lugs. The suspension bar is a steel cable structure. The length of the long reinforcing bar is less than the transverse length of the top side of the steel cover plate. The number of lateral reinforcing bars is multiple sets and they are evenly hinged longitudinally to the inner side of the steel cover plate.

[0014] Preferably, both the old bridge and the new bridge have longitudinally arranged hinged grooves on the top side of their flange plates to accommodate steel cover plates. On the outer side of the steel cover plates, there are multiple sets of vertically penetrating grouting holes evenly arranged corresponding to the lateral reinforcement. On the inner side of the hinged grooves of both the old bridge and the new bridge, there are vertically extending consolidation holes. On the opposite sides of the old bridge and the new bridge below the two sets of hinged grooves, there are side grooves to accommodate the lateral rotation and insertion of short reinforcement bars. The side grooves are connected to the consolidation holes on the inner side of the hinged grooves.

[0015] Preferably, the inner side of the hinged groove above the multiple sets of side grooves is provided with a top groove to accommodate the long ribs. The depth of the top groove is equal to the diameter of the long ribs. Multiple sets of hinge ears are provided on the opposite sides of the top of the two sets of steel cover plates. The hinge ears of the two sets of steel cover plates are longitudinally staggered to form a zipper-like distribution structure. The longitudinal pull shaft passes through the multiple sets of hinge ears of the two sets of steel cover plates in sequence to support the hinged engagement of the two sets of steel cover plates.

[0016] The construction method for widening the old and new viaducts includes the following steps:

[0017] a. Cut and remove the guardrail at the cantilever position of the old bridge. Chisel away 25cm from the top side of the flange plates of the old and new bridges to form a hinged groove, exposing the transverse steel reinforcement of the bridge deck. Then, press two sets of steel cover plates, which are hinged together by longitudinal tension shafts, onto the old and new bridges. Drill holes on the new and old bridges to create side grooves, top grooves, and consolidation holes, ensuring that the consolidation holes at the corresponding positions are connected to the side grooves. Beforehand, ram wooden strips into the grouting holes and insert them into the consolidation holes to temporarily fix the steel cover plates between the old and new bridges.

[0018] b. The steel bottom formwork, together with two sets of templates and a retainer, forms a disassembly and replacement structure. When this disassembly and replacement structure needs to be installed between the two sets of steel cover plates, the top frame of the steel bottom formwork is inserted into the receiving groove of the two sets of steel cover plates. The steel bottom formwork is supported by rollers, which drive the retainer to slide between the two sets of steel cover plates along the length of the bridge. Then, the knob is turned to align the locking block with the through hole of the fixing ear, and the retainer is pushed upward to push the locking block above the fixing ear of the two sets of steel cover plates, ensuring that the locking block is separated from the through hole. At this time, the knob is rotated to drive the retainer and the drum to rotate. The rotation of the drum is used to wind up the steel cable. The steel cable is used to pull the drooping template upward to flip it over and cover the opening at the outer end of the two sets of steel cover plates, thereby closing the grouting cavity.

[0019] c. Then, pull down the retainer to rotate the locking block into the slot of the fixing ear, and use the spring to keep the locking block in a locked position in the slot, thereby achieving the locking action of the steel bottom mold and the two side mold plates in the position of the steel cover plate. During the process of the two sets of steel cover plates being placed into the gap between the old bridge and the new bridge, the long and short bars of the lateral reinforcement are inclined downward around the reinforcement connecting ear under their own weight to ensure that the lateral reinforcement can be in a folded-down state. When the steel cover plate is pressed into the hinge groove, the outer end of the long bar extends into the top groove and is blocked by the top groove. Under the downward pressure of the steel cover plate, the long bar rotates outward to a horizontal state and extends horizontally into the top groove. The suspension bar connected downward by the long bar pulls multiple sets of short bars to a horizontal state simultaneously, so as to extend the short bars into the side grooves on both sides, thereby realizing the automatic reinforcement action of the grouting mold cavity.

[0020] d. Lay plastic sheeting on the top side of the bottom plate of the steel bottom formwork, use lateral reinforcement to support the steel cover plate and the bridge body on both sides, and use the steel bottom formwork in conjunction with the steel cover plate and the composite formwork to seal the grouting cavity. Remove the wooden strips in the grouting holes and the consolidation holes, and inject ultra-fast hard steel fiber cement mortar into the grouting holes. After the cement mortar is injected into the grouting cavity along the grouting holes, consolidation holes and side grooves, the cement mortar overflows through multiple sets of grouting holes to fill the gaps in the joint grooves and the channels of the consolidation holes and grouting holes.

[0021] e. After the concrete inside the two sets of steel cover plates at this position has cured, rotate the knob to release the locking block downwards along the through hole. At the same time, rotate the knob to drive the drum to loosen the tension of the steel cable on the formwork. At this time, rotate the formwork downwards around the formwork base to a vertical position. The steel bottom formwork is moved down to the position where the support roller is pressed against the top side of the side. At this time, the disassembly and replacement structure composed of the steel bottom formwork, the two sets of formwork, and the retainer is moved longitudinally. That is, the disassembly and replacement structure is slid along the bridge splicing length to the bottom side of the other two sets of steel cover plates to achieve continuous fixation of the bridge splicing position in the length direction.

[0022] The beneficial effects are as follows: This invention achieves bridge widening by installing two sets of hinged steel cover plates between the old and new bridges, and sets up quick-removable steel bottom molds on the bottom side of the two sets of steel cover plates. The steel bottom molds can be pushed along the length of the bridge to move the retaining frame and the composite formwork, thereby using the steel bottom molds and composite formwork as reusable support structures. This enables continuous support during the widening of the bridge along its length, solving the problem of cumbersome and difficult support between the two sides of the bridge and improving the efficiency of bridge widening.

[0023] Meanwhile, the grouting mold can move synchronously with the steel bottom mold to achieve position replacement. The grouting mold can be flipped up and lowered by rotating the retainer, which improves the convenience of demolding.

[0024] In addition, lateral anchor bars that can rotate downwards are installed on the outer side of both sets of steel cover plates. When the steel cover plates are placed in the gap between the two bridge bodies, the lateral anchor bars can be bent down and folded up. After the steel cover plates are placed in place and fit the hinged groove, the long bars are inserted into the top groove and the suspension bars are used to pull multiple sets of short bars to rotate and extend into the side groove, so as to realize the automatic layout of the lateral anchor bars.

[0025] The grouting cavity between the steel cover plate and the outer bridge body is connected to the consolidation hole and grouting hole above through the side groove. While grouting and fixing the steel cover plate, mortar is injected into the side groove, consolidation hole and grouting hole to realize the lateral reinforcement and the integrated curing of the top side of the steel cover plate, thereby improving the structural connection strength of the joint between the two bridge bodies. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a front view structural diagram of the present invention;

[0028] Figure 2 This is a three-dimensional structural schematic diagram of the present invention;

[0029] Figure 3 This is a structural breakdown diagram of the present invention;

[0030] Figure 4 This is a three-dimensional structural schematic diagram of the hinged groove of the present invention;

[0031] Figure 5 This is a structural breakdown diagram of the template of the present invention;

[0032] Figure 6 This is a partial structural breakdown diagram of the present invention;

[0033] Figure 7 This is a partial structural schematic diagram of the steel cover plate of the present invention;

[0034] Figure 8 yes Figure 7 Enlarged view of the structure at point A;

[0035] Figure 9 This is a three-dimensional structural schematic diagram of the steel bottom mold of the present invention;

[0036] Figure 10 This is a partial structural schematic diagram of the steel bottom mold of the present invention;

[0037] Figure 11This is a three-dimensional structural schematic diagram of another aspect of the present invention;

[0038] Figure 12 This is a three-dimensional structural schematic diagram of the new bridge of the present invention.

[0039] The annotations in the attached figures are explained as follows:

[0040] 1. Old bridge; 2. New bridge; 3. Steel cover plate; 301. Hinge lug; 302. Receiving groove; 302a. Side edge; 303. Fixing lug; 303a. Through hole; 303b. Slot; 304. Rebar connection lug; 305. Grouting hole; 4. Steel bottom formwork; 401. Base plate; 402. Top frame; 403. Support roller; 404. Formwork opening base; 405. Reinforcing plate; 5. Cage; 501. Locking block; 502. Knob ; 502a, Holding groove; 503, Spring; 504, Drum; 505, Steel cable; 6, Longitudinal tension shaft; 7, Lateral reinforcement; 701, Long reinforcement; 702, Short reinforcement; 703, Connecting shaft; 704, Lifting lug; 705, Suspension reinforcement; 8, Formwork assembly; 801, Support lug; 802, Installation cavity; 803, Traction frame; 9, Bridge cap beam; 10, Connecting groove; 11, Side groove; 12, Top groove; 13, Consolidation hole. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0042] See Figures 1-12 As shown, the present invention provides a structure for widening an old and new elevated bridge, including an old bridge 1, a new bridge 2, and two sets of steel cover plates 3. The two sets of steel cover plates 3 are symmetrically arranged laterally between the flange plates of the old bridge 1 and the new bridge 2. A longitudinal tension shaft 6 is provided between the two sets of steel cover plates 3 to support the rotation of the two sets of steel cover plates 3. The longitudinal tension shaft 6 supports the two sets of steel cover plates 3 to maintain a hinged state. A longitudinally extending steel bottom mold 4 is provided on the bottom side of the two sets of steel cover plates 3. A retainer 5 is vertically inserted on the bottom side of the steel bottom mold 4 and extends between the two sets of steel cover plates 3 to connect the steel bottom mold 4 and the steel cover plates 3. The steel bottom mold 4 is fixed to the bottom side of the two sets of steel cover plates 3 by the retainer 5.

[0043] Between the two sets of steel cover plates 3, there are vertically staggered fixing ears 303 corresponding to the retainer 5. The retainer 5 vertically penetrates the two sets of fixing ears 303. The top of the fixing ear 303 is fixed with a horizontally extending strip-shaped locking block 501. The middle of the fixing ear 303 has a vertical through hole 303a to accommodate the locking block 501. The top side of the fixing ear 303 is provided with a locking groove 303b to engage and lock the locking block 501. The through hole 303a and the locking groove 303b are arranged in a cross shape so that after the locking block 501 is dislodged from the locking groove 303b, it can be rotated to the position of the corresponding through hole 303a, which can separate the retainer 5 from the fixing ears 303 of the two sets of steel cover plates 3, thereby realizing the demolding action of the steel bottom mold 4 on the steel cover plate 3.

[0044] As an optional implementation, a knob 502 is fixed at the bottom of the retainer 5. The retainer 5 vertically penetrates the steel bottom mold 4 and is in clearance fit with the steel bottom mold 4. A spring 503 is sleeved on the outer side of the bottom of the retainer 5. The two ends of the spring 503 are respectively pressed against the bottom side of the steel bottom mold 4 and the top side of the knob 502 to pull the top end of the retainer 5 to press against the inside of the slot 303b.

[0045] A horizontal plate extends horizontally from the top side of the steel cover plate 3 to form a transverse plate. A vertical plate extending vertically between the old bridge 1 and the new bridge 2 is fixed to one side of the transverse plate. A receiving groove 302 for accommodating the fixing lug 303 runs longitudinally through the inner side of the vertical plate. The bottom edge of the receiving groove 302 is bent inward to form a side edge 302a supporting the steel bottom mold 4. Lateral reinforcing bars 7 extending outward are provided on the inner side of the steel cover plate 3. The steel bottom mold 4 includes a bottom plate 401 that abuts against the bottom edge of the steel cover plate 3. A spring 503 abuts against the bottom plate 401 on its top side to improve the pressing state between the bottom plate 401 and the bottom edge of the steel cover plate 3. A spring 503 is provided above the bottom plate 401. A top frame 402 is placed in the receiving groove 302 between two sets of steel cover plates 3. Multiple sets of one-way wheel structures are evenly arranged on both sides of the top frame 402. The side edge 302a can support the support wheel 403 to drive the steel bottom mold 4 to slide longitudinally, so that the steel bottom mold 4 can move inside the steel cover plates 3 arranged in the length direction of the bridge. A reinforcing plate 405 supporting the top frame 402 is fixed on the top side of the bottom plate 401. A grouting cavity is formed between the bottom plate 401 and the steel cover plate 3. The bottom plate 401 can be opened on both the front and rear sides and is equipped with a closing mold plate 8 for the grouting cavity.

[0046] Both the front and rear sides of the base plate 401 are fixed with mold opening seats 404 to support the rotation of the mold assembly form 8. The bottom side of the mold assembly form 8 is fixed with support ears 801 that cooperate with the mold opening seats 404 to form a hinge frame, ensuring that the base plate 401 can support the mold assembly form 8 to close the front and rear openings of the grouting mold cavity upwards. A drum 504 is coaxially fixed to the outside of the retainer 5 below the fixed ears 303. The bottom side of the mold assembly form 8 has a longitudinally penetrating mounting groove 802. A traction frame 803 is transversely fixed inside the mounting groove 802. The outside of the drum 504 is wound. The steel cable 505, which is fixed to the traction frame 803, drives the overall rotation and opening and closing of the formwork 8. The lateral reinforcement 7 includes long reinforcements 701 arranged horizontally inside the grouting mold cavity. Below the long reinforcements 701, multiple sets of short reinforcements 702 are evenly arranged vertically and parallel to each other. The long reinforcements 701 and short reinforcements 702 are all fixed with a connecting shaft 703 near the steel cover plate 3. The outside of the steel cover plate 3 is provided with a reinforcement connecting ear 304 that is hinged to the connecting shaft 703 to support the rotation of the long reinforcements 701 and short reinforcements 702.

[0047] Specifically, both the long reinforcing bars 701 and the short reinforcing bars 702 are fixed with lifting lugs 704 on their outer sides. A suspension bar 705 is vertically connected between adjacent sets of lifting lugs 704. The suspension bar 705 is a steel cable structure, used to connect the long reinforcing bars 701 and multiple short reinforcing bars 702. The length of the long reinforcing bar 701 is less than the transverse length of the top side of the steel cover plate 3. Multiple sets of lateral reinforcing bars 7 are longitudinally and evenly hinged to the inner side of the steel cover plate 3. Both the old bridge 1 and the new bridge 2 have longitudinally arranged hinged grooves 10 on the top side of their flanges to accommodate the steel cover plate 3. The outer side of the steel cover plate 3... Multiple sets of vertically penetrating grouting holes 305 are evenly arranged on the corresponding lateral anchoring bars 7. Vertically extending consolidation holes 13 are provided on the old bridge 1 and new bridge 2 inside the mandrel groove 10. Side grooves 11 are provided on the opposite sides of the old bridge 1 and new bridge 2 below the two sets of mandrel grooves 10 to accommodate the lateral rotation of short reinforcing bars 702. The side grooves 11 are connected to the consolidation holes 13 inside the mandrel groove 10 so that the concrete mortar poured into the grouting mold cavity can be solidified in the consolidation holes 13 and grouting holes 305, thereby realizing the fixed connection of the steel cover plate 3 on the outside of the bridge flange plate.

[0048] The inner side of the hinged groove 10 above the multiple sets of side grooves 11 is provided with a top groove 12 to accommodate the long bar 701. The depth of the top groove 12 is equal to the diameter of the long bar 701, ensuring that the outer end of the long bar 701 can be completely pressed into the top groove 12, so that the long bar 701 can be fixed to the hinged groove 10 by embedding it with concrete mortar. Multiple sets of hinge ears 301 are provided on the opposite sides of the top of the two sets of steel cover plates 3. The hinge ears 301 of the two sets of steel cover plates 3 are longitudinally staggered to form a zipper-like distribution structure. The longitudinal pull shaft 6 passes through the multiple sets of hinge ears 301 of the two sets of steel cover plates 3 in sequence to support the hinged engagement of the two sets of steel cover plates 3.

[0049] The construction method for widening the old and new viaducts includes the following steps:

[0050] a. Construct a new bridge 2 outside the new bridge 2. Support the old bridge 1 and the new bridge 2 with the bridge cap beam 9 to keep them parallel. Cut and remove the guardrail at the cantilever position of the old bridge 1. Chisel out a 25cm wide groove 10 on the top side of the flange plate of the old bridge 1 and the new bridge 2. The depth of the groove 10 is not less than the thickness of the top side of the steel cover plate 3, exposing the transverse steel reinforcement of the bridge deck. Then, press two sets of steel cover plates 3, which are hinged together by the longitudinal tension shaft 6, onto the old bridge 1 and the new bridge 2. Drill holes on the new bridge 2 and the old bridge 1 to create side grooves 11, top grooves 12 and consolidation holes 13. Ensure that the consolidation holes 13 at the corresponding positions are connected to the side grooves 11. Beforehand, ram wooden strips into the grouting holes 305 so that they can pass into the consolidation holes 13 to temporarily fix the steel cover plates 3 between the old bridge 1 and the new bridge 2.

[0051] b. The steel bottom mold 4, together with two sets of templates 8 and retainer 5, forms a disassembly and replacement structure. When this disassembly and replacement structure needs to be installed between the two sets of steel cover plates 3, the top frame 402 of the steel bottom mold 4 is inserted into the receiving groove 302 of the two sets of steel cover plates 3. The steel bottom mold 4 is supported by the roller 403, which drives the retainer 5 to slide into the two sets of steel cover plates 3 along the length of the bridge. Then, the knob 502 is rotated to align the locking block 501 with the through hole 303a of the fixing ear 303, and the retainer 5 is pushed upward to push the locking block 501 above the fixing ear 303 of the two sets of steel cover plates 3, ensuring that the locking block 501 is separated from the through hole 303a. At this time, the knob 502 is rotated to drive the retainer 5 and the drum 504 to rotate. The rotation of the drum 504 is used to wind up the steel cable 505. The steel cable 505 is used to pull the drooping template 8 upward to flip and cover the opening at the outer end of the two sets of steel cover plates 3, thereby closing the grouting cavity.

[0052] c. Then, pull down the retainer 5 to rotate and engage the locking block 501 into the slot 303b of the fixing ear 303. The spring 503 keeps the locking block 501 in a downward-facing, locked state within the slot 303b, thereby achieving the locking action of the steel bottom mold 4 and the two side mold plates 8 at the position of the steel cover plate 3. During the process of inserting the two sets of steel cover plates 3 into the gap between the old bridge 1 and the new bridge 2, the long bars 701 and short bars 702 of the lateral reinforcement 7 tilt downward around the reinforcement connecting ear 304 under their own weight, ensuring the lateral reinforcement 7 It can be in a folded-down state. When the steel cover plate 3 is pressed tightly into the hinge groove 10, the outer end of the long rib 701 extends into the top groove 12 and is blocked by the top groove 12. Under the pressure of the steel cover plate 3, the long rib 701 rotates outward to a horizontal state. The long rib 701 extends horizontally into the top groove 12. The suspension rib 705 connected downward to the long rib 701 pulls multiple sets of short ribs 702 to be simultaneously supported to a horizontal state, so that the short ribs 702 can be extended into the side grooves 11 on both sides, realizing the automatic rebar installation action of the grouting mold cavity.

[0053] d. A plastic sheet is laid on the top side of the bottom plate 401 of the steel bottom formwork 4. Lateral reinforcement bars 7 are used to support the steel cover plate 3 and the bridge body on both sides. After the steel bottom formwork 4, together with the steel cover plate 3 and the composite formwork 8, is used to seal the grouting cavity, the wooden strips in the grouting hole 305 and the consolidation hole 13 are removed. Ultra-fast hard steel fiber cement mortar is injected into the grouting hole 305. After the cement mortar is injected into the grouting cavity along the grouting hole 305, the consolidation hole 13 and the side groove 11, the cement mortar overflows through multiple sets of grouting holes 305 to fill the gaps in the hinge groove 10 and the channels of the consolidation hole 13 and the grouting hole 305.

[0054] e. After the concrete inside the two sets of steel cover plates 3 at this position has cured, rotate the knob 502 to release the locking block 501 downward along the through hole 303a. At the same time, rotate the knob 502 to drive the drum 504 to rotate to loosen the tension of the steel cable 505 on the template 8. At this time, rotate the template 8 downward around the mold base 404 to a vertical position. The steel bottom mold 4 is moved down as a whole until the support roller 403 abuts against the top side of the side edge 302a. At this time, the disassembly and replacement structure composed of the steel bottom mold 4, the two sets of templates 8 and the retainer 5 is moved longitudinally. That is, the disassembly and replacement structure is slid along the bridge splicing length direction to the bottom side of the other two sets of steel cover plates 3, so as to achieve continuous fixation of the bridge splicing position in the length direction.

[0055] By installing two sets of hinged steel cover plates 3 between the old bridge 1 and the new bridge 2, the bridge body is widened and connected. A quick-removable steel bottom formwork 4 is set on the bottom side of the two sets of steel cover plates 3. The steel bottom formwork 4 can be pushed along the length of the bridge to move the retaining frame 5 and the composite formwork 8. Thus, the steel bottom formwork 4 and the composite formwork 8 are used as reusable formwork structures, and continuous formwork is achieved during the widening of the bridge along its length. This solves the problem of cumbersome and difficult formwork between the two bridge bodies and improves the efficiency of bridge widening.

[0056] Meanwhile, the formwork 8, which serves as the grouting mold, can move synchronously with the steel bottom mold 4 to achieve position replacement. The formwork 8 can be flipped up and lowered by rotating the retainer 5, which improves the convenience of demolding.

[0057] In addition, lateral anchor bars 7 that can rotate downwards are provided on the outer side of both sets of steel cover plates 3. When the steel cover plate 3 is placed in the gap between the two bridge bodies, the lateral anchor bars 7 can be bent downwards and folded up. After the steel cover plate 3 is placed in place and fits the hinge groove 10, the long bar 701 is inserted into the top groove 12 and the suspension bar 705 pulls multiple sets of short bars 702 to rotate and extend into the side groove 11, so as to realize the automatic layout of the lateral anchor bars 7.

[0058] The grouting cavity between the steel cover plate 3 and the outer bridge body is connected to the consolidation hole 13 and the grouting hole above through the side groove 11. While grouting and fixing the steel cover plate 3, mortar is injected into the side groove 11, the consolidation hole 13 and the grouting hole to achieve the integrated curing of the lateral reinforcement 7 and the top side of the steel cover plate 3, thereby improving the structural connection strength at the joint of the two bridge bodies.

[0059] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A new structure for widening old and new viaducts, characterized in that: It includes two sets of steel cover plates (3), which are symmetrically arranged laterally between the flange plates of the old bridge (1) and the new bridge (2). A longitudinal tension shaft (6) is provided between the two sets of steel cover plates (3) to support the rotation of the two sets of steel cover plates (3). A longitudinally extending steel bottom mold (4) is provided on the bottom side of the two sets of steel cover plates (3). A retainer (5) is vertically inserted on the bottom side of the steel bottom mold (4) and extends between the two sets of steel cover plates (3) to connect the steel bottom mold (4) and the steel cover plate (3). Between the two sets of steel cover plates (3), there are vertically staggered fixing ears (303) corresponding to the retainer (5). The retainer (5) vertically penetrates the two sets of fixing ears (303), and a locking block (501) is fixed at the top of the retainer (5). The middle of the fixing ear (303) has a through hole (303a) that accommodates the locking block (501) to pass through vertically. The top side of the fixing ear (303) is provided with a locking groove (303b) for locking the locking block (501). The through hole (303a) and the locking groove (303b) are arranged in a cross shape. The steel cover plate (3) extends horizontally on the top side to form a horizontal plate. A vertical plate is fixed on one side of the horizontal plate, extending vertically between the old bridge (1) and the new bridge (2). A receiving groove (302) for accommodating the fixing lug (303) is longitudinally penetrating the inner side of the vertical plate. The bottom edge of the receiving groove (302) is bent inward to form a side edge (302a) supporting the steel bottom mold (4). Lateral reinforcing bars (7) extending outward are provided on the inner side of the steel cover plate (3). The steel bottom mold (4) includes a bottom plate (401) that abuts against the bottom edge of the steel cover plate (3). A top frame (402) is provided above the bottom plate (401) and extends longitudinally into the receiving groove (302) between the two sets of steel cover plates (3). Multiple sets of support rollers (403) are evenly arranged longitudinally on both sides of the top frame (402). The side edge (302a) can support the support rollers (403) to drive the steel bottom mold (4) to slide longitudinally. A reinforcing plate (405) supporting the top frame (402) is fixed on the top side of the bottom plate (401). A grouting cavity is formed between the bottom plate (401) and the steel cover plate (3). A closing template (8) for closing the grouting cavity can be opened on both the front and rear sides of the bottom plate (401).

2. The new and old viaduct widening structure according to claim 1, characterized in that: A knob (502) is fixed at the bottom of the retainer (5). The retainer (5) extends vertically through the steel bottom mold (4) and is in clearance fit with the steel bottom mold (4). A spring (503) is sleeved on the outer side of the bottom of the retainer (5). The two ends of the spring (503) abut against the bottom side of the steel bottom mold (4) and the top side of the knob (502) respectively, so as to pull the top end of the retainer (5) to abut against the inside of the slot (303b).

3. The new and old viaduct widening structure according to claim 1, characterized in that: The base plate (401) has a mold opening seat (404) fixed on both the front and rear sides to support the rotation of the mold assembly template (8). The bottom side of the mold assembly template (8) has a support ear (801) that cooperates with the mold opening seat (404) to form a hinge frame. The retainer (5) below the fixed ear (303) has a drum (504) coaxially fixed on the outside. The bottom side of the mold assembly template (8) has a longitudinally penetrating mounting groove (802). The mounting groove (802) has a traction frame (803) fixed laterally inside. The outside of the drum (504) has a steel cable (505) that pulls and drags the traction frame (803) to drive the mold assembly template (8) to rotate and open and close as a whole.

4. The new and old viaduct widening structure according to claim 3, characterized in that: The lateral anchoring (7) includes a long rib (701) arranged laterally inside the grouting mold cavity. Below the long rib (701), there are multiple sets of short ribs (702) arranged vertically and evenly. The long rib (701) and the short rib (702) are all fixed with a connecting shaft (703) near the end of the steel cover plate (3). The outer side of the steel cover plate (3) is provided with anchoring connecting ears (304) that are hinged to the connecting shaft (703) to support the rotation of the long rib (701) and the short rib (702).

5. The new and old viaduct widening structure according to claim 4, characterized in that: The long reinforcing bar (701) and the short reinforcing bar (702) are both fixed with lifting lugs (704) on the outside. A suspension reinforcing bar (705) is vertically connected between two adjacent sets of lifting lugs (704). The suspension reinforcing bar (705) is a steel cable structure. The length of the long reinforcing bar (701) is less than the transverse length of the top side of the steel cover plate (3). The number of lateral anchoring bars (7) is multiple sets and they are evenly hinged to the inner side of the steel cover plate (3) in the longitudinal direction.

6. The new and old viaduct widening structure according to claim 5, characterized in that: Both the old bridge (1) and the new bridge (2) have longitudinally arranged hinged grooves (10) on the top side of their flange plates to accommodate steel cover plates (3). The outer side of the steel cover plates (3) is uniformly provided with multiple sets of vertically penetrating grouting holes (305) corresponding to the lateral reinforcement (7). The old bridge (1) and the new bridge (2) on the inner side of the hinged grooves (10) are provided with vertically extending consolidation holes (13). The old bridge (1) and the new bridge (2) on the opposite side below the two sets of hinged grooves (10) are provided with side grooves (11) to accommodate short reinforcement bars (702) that rotate laterally and extend into them. The side grooves (11) are connected to the consolidation holes (13) on the inner side of the hinged grooves (10).

7. The new and old viaduct widening structure according to claim 6, characterized in that: The inner side of the hinged groove (10) above the multiple sets of side grooves (11) is provided with a top groove (12) to accommodate the long rib (701). The depth of the top groove (12) is equal to the diameter of the long rib (701). Multiple sets of hinge ears (301) are provided on the opposite sides of the top of the two adjacent sets of steel cover plates (3). The hinge ears (301) of the two sets of steel cover plates (3) are longitudinally staggered to form a zipper-like distribution structure. The longitudinal pull shaft (6) passes through the multiple sets of hinge ears (301) of the two sets of steel cover plates (3) in sequence to support the hinged engagement of the two sets of steel cover plates (3).

8. The construction method for widening the old and new viaducts according to any one of claims 1-7, characterized in that, Includes the following steps: a. Cut and remove the guardrail at the cantilever position of the old bridge (1), chisel 25cm off the top side of the flange plate of the old bridge (1) and the new bridge (2) to form a hinge groove (10) to expose the transverse steel bars of the bridge deck, and then press two sets of steel cover plates (3) that are hinged together by the longitudinal tension shaft (6) onto the old bridge (1) and the new bridge (2), and drill holes on the new bridge (2) and the old bridge (1) to chisel out the side groove (11), the top groove (12) and the consolidation hole (13), to ensure that the consolidation hole (13) at the corresponding position is connected to the side groove (11), and ram wooden strips into the grouting hole (305) in advance so that they can pass into the consolidation hole (13) to temporarily fix the steel cover plate (3) between the old bridge (1) and the new bridge (2); b. The steel bottom mold (4) is combined with two sets of templates (8) and a retainer (5) to form a disassembly and replacement structure. When the disassembly and replacement structure needs to be installed between the two sets of steel cover plates (3), the top frame (402) of the steel bottom mold (4) is inserted into the receiving groove (302) of the two sets of steel cover plates (3). The steel bottom mold (4) is supported by the roller (403) and the retainer (5) is slid into the two sets of steel cover plates (3) along the length of the bridge. Then, the knob (502) is turned to align the locking block (501) with the through hole (303) of the fixing ear (303). 03a), and push the retainer (5) upward to push the locking block (501) above the fixing ears (303) of the two sets of steel cover plates (3), ensuring that the locking block (501) is separated from the through hole (303a). At this time, rotate the knob (502) to drive the retainer (5) and the drum (504) to rotate. Use the rotation of the drum (504) to wind up the steel cable (505). Use the steel cable (505) to pull the drooping template (8) upward to flip and cover the opening at the outer end of the two sets of steel cover plates (3), thereby closing the grouting mold cavity; c. Then pull down the retainer (5) to rotate the locking block (501) into the slot (303b) of the fixing ear (303), and keep the locking block (501) in the slot (303b) by the spring (503), thereby realizing the locking action of the steel bottom mold (4) and the two side mold plates (8) in the position of the steel cover plate (3). During the process of the two sets of steel cover plates (3) being placed into the gap between the old bridge (1) and the new bridge (2), the long bar (701) and short bar (702) of the lateral reinforcement (7) are inclined downward around the reinforcement connecting ear (304) under their own weight to ensure the lateral reinforcement. The rib (7) can be in a folded-down state. When the steel cover plate (3) is pressed into the hinge groove (10), the outer end of the long rib (701) extends into the top groove (12) and is blocked by the top groove (12). Under the pressure of the steel cover plate (3), the long rib (701) rotates outward to a horizontal state. The long rib (701) extends horizontally into the top groove (12). The suspension rib (705) connected downward by the long rib (701) pulls multiple sets of short ribs (702) to a horizontal state simultaneously, so as to extend the short ribs (702) into the side grooves (11) on both sides, thereby realizing the automatic rib planting action of the grouting mold cavity. d. Lay plastic cloth on the top side of the bottom plate (401) of the steel bottom formwork (4), use lateral reinforcement (7) to support the steel cover plate (3) and the bridge body on both sides, and use the steel bottom formwork (4) in conjunction with the steel cover plate (3) and the formwork (8) to seal the grouting mold cavity. Remove the wooden strips in the grouting hole (305) and the consolidation hole (13), and inject ultra-fast hard steel fiber cement mortar into the grouting hole (305). After the cement mortar is injected into the grouting mold cavity along the grouting hole (305), the consolidation hole (13) and the side groove (11), after the grouting mold cavity is filled, the cement mortar overflows through multiple sets of grouting holes (305) to fill the gaps in the hinge groove (10) and the channels of the consolidation hole (13) and the grouting hole (305). e. After the concrete inside the two sets of steel cover plates (3) at this position is cured, rotate the knob (502) to release the clip (501) downward along the through hole (303a). At the same time, rotate the knob (502) to drive the drum (504) to rotate to loosen the tension of the steel cable (505) on the template (8). At this time, rotate the template (8) downward around the mold base (404) to the vertical position. The steel bottom mold (4) is moved down as a whole to the support roller (403) and pressed against the top side of the side edge (302a). At this time, the steel bottom mold (4) is moved longitudinally along the disassembly and replacement structure composed of the two sets of templates (8) and the retainer (5). That is, the disassembly and replacement structure is slid along the bridge splicing length direction to the bottom side of the other two sets of steel cover plates (3) to realize the continuous fixation of the bridge splicing position in the length direction.

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