Concrete hollow slab girder bridge reinforcing method and system based on bridge deck truss prestress

Abstract

The invention belongs to the technical field of bridge maintenance and reinforcement, and discloses a concrete hollow slab girder bridge reinforcement method and system based on bridge deck truss prestress. The method comprises the steps that an existing concrete guardrail is dismantled, and cantilever sections on the outer sides of side plates are exposed; bridge deck counter-force trusses are installed on the two sides of the bridge deck; a lower transverse bearing component is arranged at the bottom of the bridge; a tensioning piece is arranged in the vertical cable penetrating pipe in a penetrating mode, and the lower end of the tensioning piece is connected with the lower transverse bearing component; tensioning force is applied to the tensioning piece through the upper end tensioning anchoring assembly, and the tensioning piece is locked, so that the lower transverse bearing component upwards abuts against the bottoms of the multiple hollow slab beams in a pressing mode; and the bridge deck counter-force truss is reserved and forms a bridge side protection boundary. The transverse overall stress state of the bridge can be improved, middle sinking of the bridge floor is relieved, inter-plate cracking and single-plate crack development are restrained, main construction procedures are completed on the bridge floor, and the method is suitable for the bridge difficult to construct under the bridge.

Description

Technical Field

[0001] This invention relates to the field of bridge maintenance and reinforcement technology, specifically to a method and system for reinforcing concrete hollow slab beam bridges based on prestressed bridge deck trusses. Background Technology

[0002] Hollow concrete slab girder bridges are widely used in highway and municipal bridges due to their relatively simple structure, convenient prefabrication and installation, high construction efficiency, and moderate project cost. Especially in small and medium-span bridges, precast reinforced concrete hollow slab girder bridges and prestressed concrete hollow slab girder bridges have long been common bridge types. These bridges typically consist of multiple hollow slab girders arranged side-by-side along the transverse direction of the bridge deck to form the superstructure. Adjacent hollow slab girders share loads through hinge joints, the bridge deck pavement, and related connections, forming a certain overall transverse load-bearing capacity.

[0003] As bridges age, they are susceptible to various structural defects due to repeated vehicle loads, overloading, environmental erosion, structural aging, and the degradation of original lateral connection performance. Common defects include mid-deck settlement, cracking between adjacent hollow slab beams, cracking of the pavement layer along the joints, cracking of the bottom or web of a single hollow slab beam, and crack propagation caused by abnormal stress in local components. These defects interact, weakening the lateral load-bearing capacity of the bridge superstructure, further reducing the bridge's overall integrity, durability, and driving comfort, and in severe cases, even affecting the bridge's normal operational safety.

[0004] Current treatment methods for defects in hollow concrete slab girder bridges mainly involve crack sealing, pressure grouting, pavement repair, steel plate bonding, fiber composite bonding, adding substructure supports, or partial component replacement. While these techniques can repair localized cracks or damaged areas under certain conditions, they often fall short in addressing issues such as mid-deck subsidence, inter-slab cracking, and reduced collaborative capacity among multiple hollow slab girders caused by insufficient overall lateral load-bearing capacity. In particular, simply sealing or grouting the cracks themselves can improve the appearance of the defects to some extent, but it fails to restore or enhance the lateral load-bearing capacity and collaborative working capacity of the hollow slab girder bridge from an overall load-bearing perspective, thus making it difficult to effectively prevent the recurrence or continued development of defects.

[0005] Furthermore, some existing reinforcement methods require construction work at the bottom of the bridge, such as setting up support systems and installing reinforcement components under the beams. For high-pier bridges, bridges spanning valleys, or bridges with limited construction conditions under the bridge, organizing construction from below the bridge usually presents challenges such as difficulties in setting up work areas, high risks of working at heights, long construction periods, complex traffic management, and high construction costs. In some existing bridges, the terrain under the bridge is complex, or the clearance under the bridge is high, making traditional substructure construction methods difficult to implement and requiring high safety standards, thus hindering the widespread application of relevant reinforcement technologies.

[0006] Therefore, how to provide a reinforcement method and system that can be mainly implemented on the bridge deck, can provide lateral overall support for concrete hollow slab beam bridges, and is applicable to high piers or difficult construction conditions under the bridge has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] This invention provides a method and system for strengthening concrete hollow slab beam bridges based on bridge deck truss prestressing, in order to overcome the problems of insufficient overall strengthening effect of existing technologies for defects such as mid-slab settlement, inter-slab cracking and single-slab cracking of concrete hollow slab beam bridges, and the fact that strengthening construction relies heavily on under-bridge operations, is difficult to implement and has high risks.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] In a first aspect, the present invention provides a method for strengthening a concrete hollow slab beam bridge based on prestressed bridge deck trusses, comprising the following steps:

[0010] Remove the existing concrete guardrail to expose the outermost cantilever section of the outermost hollow slab beam.

[0011] Bridge deck reaction trusses are installed on both sides of the bridge deck. The bridge deck reaction trusses include an upper chord, a lower chord, diagonal web members, and vertical cable-passing tubes. The bridge deck reaction trusses are fixed to the cantilever section on the outer side of the side plate by means of bridge deck anchoring components.

[0012] A lower transverse support member is installed at the bottom of the bridge. The lower transverse support member extends laterally along the bridge and is located below the bottom of multiple hollow slab beams.

[0013] The tensioning member is inserted into the vertical cable-passing tube from top to bottom. After the lower end of the tensioning member passes through the connecting hole on the lower transverse support member, the lower anchor head and the lower anti-detachment plate are installed on the lower side of the lower transverse support member. The upper end of the tensioning member passes through the top of the vertical cable-passing tube.

[0014] Install an upper tensioning and anchoring assembly at the top of the vertical cable-passing pipe. Use a jack to apply tension force to the upper end of the tensioning member. After the predetermined tension force is reached, use the upper tensioning and anchoring assembly to lock the tensioning member.

[0015] Once locked, the tensioning member remains in tension, while the lower transverse support member moves upward and presses against the bottom of multiple hollow slab beams.

[0016] The bridge deck reaction trusses are retained along both sides of the bridge deck, with the top of the bridge deck reaction trusses higher than the surface of the bridge deck pavement, forming a protective boundary on the bridge side.

[0017] Furthermore, the existing concrete guardrails are removed along the entire longitudinal section of the bridge, or removed in sections along the longitudinal section of the bridge; the bridge deck reaction trusses and lower transverse support components are set in the corresponding middle subsidence area of ​​the bridge deck, the inter-slab joint cracking area, or the crack area of ​​a single hollow slab beam; one or more sets of bridge deck reaction trusses and lower transverse support components are provided along the longitudinal section of the bridge within the same bridge span.

[0018] Furthermore, the upper chord, lower chord, and diagonal web members form a continuous truss unit, and the vertical cable-passing tubes are located at or near the truss nodes; the bridge deck reaction truss is a welded integral structure or a segmented structure prefabricated in the factory and assembled on site; stiffening or limiting components are provided at local nodes of the bridge deck reaction truss.

[0019] Furthermore, the bridge deck anchoring assembly includes a connecting base plate, anchor bolts, and stiffening plates; the connecting base plate is located at the bottom of the bridge deck reaction truss, the anchor bolts pass through the connecting base plate and are anchored into the outer cantilever section of the side plate, and the stiffening plates are connected between the bridge deck reaction truss and the connecting base plate.

[0020] Furthermore, the tensioning member is a steel cable, steel strand, or high-strength tie rod; the upper tensioning and anchoring assembly includes an upper bearing plate and an upper anchor, the upper bearing plate is located at the top of the vertical cable-passing pipe, and the upper anchor is located above the upper bearing plate; the lower anchor head and the lower anti-detachment plate are located on the lower side of the lower transverse support member; a gasket or pad is provided between the lower anchor head and the lower anti-detachment plate.

[0021] Furthermore, the lower transverse support member is a square tube, box beam, I-beam, channel beam, or composite support beam; steel pads, rubber pads, or metal pads are provided between the lower transverse support member and the bottom of several hollow slab beams; one or more lower transverse support members are provided in the same bridge span.

[0022] Secondly, the present invention provides a reinforcement system for a concrete hollow slab beam bridge based on prestressed bridge deck trusses, comprising bridge deck reaction trusses arranged longitudinally on both sides of the bridge deck, a bridge deck anchorage assembly that fixes the bridge deck reaction trusses to the cantilever section on the outer side of the side slab, a tensioning member inserted in a vertical cable-passing tube, a lower transverse support member at the bottom of the bridge, and an upper tensioning anchorage assembly at the top of the vertical cable-passing tube.

[0023] The bridge deck reaction truss includes an upper chord, a lower chord, diagonal web members, and vertical cable-passing tubes;

[0024] The lower transverse support member extends laterally along the bridge and is located below the bottom of at least two adjacent hollow slab beams.

[0025] After the lower end of the tension member passes through the connecting hole on the lower transverse support member, a lower anchor head and a lower anti-detachment plate are provided on the lower side of the lower transverse support member. After the upper end of the tension member passes through the upper tension anchor assembly, it is locked. After being locked, the tension member remains in a tensile state, and the lower transverse support member presses against the bottom of at least two adjacent hollow slab beams.

[0026] The bridge deck reaction truss is retained along both sides of the bridge deck, with the top of the bridge deck reaction truss higher than the surface of the bridge deck pavement.

[0027] Furthermore, the vertical cable-passing tube is a hollow round tube, a hollow square tube, or a hollow rectangular tube; the bridge deck reaction truss is a steel structure truss; and the surface of the bridge deck reaction truss is provided with an anti-corrosion coating or a protective layer.

[0028] Furthermore, the bridge deck anchoring assembly includes a connecting base plate, anchor bolts, and stiffening plates; the upper tension anchoring assembly includes an upper bearing plate and an upper anchor; and a gasket or pad is provided between the lower anchoring head and the lower anti-detachment plate.

[0029] Furthermore, the bridge deck reaction truss is set in the middle of the bridge deck subsidence area, the inter-slab joint cracking area, or the crack area of ​​a single hollow slab beam; one or more sets of bridge deck reaction trusses are provided along the longitudinal direction of the bridge within the same span; corresponding to each set of bridge deck reaction trusses, one or more lower transverse support members are provided at the bottom of the bridge; the outer side of the bridge deck reaction truss is provided with a protective panel, protective net, or auxiliary railing structure.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention applies prestress to the lower transverse support members at the bottom of the bridge by setting bridge deck reaction trusses on both sides of the bridge deck and using tensioning members inserted in vertical cable tubes. This causes the lower transverse support members to form an upward transverse overall support effect on the bottom of the adjacent hollow slab beams. Therefore, this invention does not only repair or fill local cracks, but can strengthen existing hollow slab beam bridges from the perspective of the overall transverse stress of the bridge. This is beneficial to improving the cooperative working state between adjacent hollow slab beams, reducing the subsidence of the middle of the bridge deck, and inhibiting the further development of inter-slab cracks and single-slab cracks.

[0032] The main tensioning and anchoring processes of this invention are completed on the bridge deck, which can make full use of the bridge deck's easy accessibility and facilitate equipment placement and construction organization, reducing reliance on construction platforms, large-scale support systems, and high-altitude work surfaces under the bridge. For high-pier bridges, bridges spanning valleys, and existing bridges with complex terrain and limited working space under the bridge, this invention can significantly reduce construction difficulty and risks, improve construction organization conditions, and has good engineering applicability.

[0033] This invention constructs a reinforcement system consisting of a bridge deck reaction truss, vertical cable-through pipes, tensioning components, upper tensioning and anchoring components, and lower transverse support components. The structural relationships are clear, the force path is clear, and the prestress is directly transferred. This system can ensure the overall stability during the tensioning process and improve the support reliability and structural durability after reinforcement, which is beneficial to improving the integrity and service performance of existing concrete hollow slab beam bridges.

[0034] Furthermore, this invention can be deployed locally or continuously according to the distribution of bridge defects, offering flexibility in its arrangement. It is suitable for targeted reinforcement of areas with concentrated defects, as well as for overall reinforcement of the entire span or bridge. After reinforcement, the bridge deck reaction truss can be retained along the outer side of the bridge deck to form a bridge side protection boundary, which helps reduce repeated construction, improves structural utilization, and meets subsequent operational needs. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall structure of an existing hollow concrete slab beam bridge in an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the cross-sectional structure of an existing hollow concrete slab beam bridge in an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the bridge structure after the existing concrete guardrails have been removed, as described in an embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram of the structure after the bridge deck reaction truss is installed on both sides of the bridge deck in an embodiment of the present invention.

[0039] Figure 5 This is a partially enlarged structural schematic diagram of the bridge deck reaction truss in an embodiment of the present invention.

[0040] Figure 6 This is a schematic diagram of the bridge bottom structure after the tensioning member and the lower transverse support member are installed in an embodiment of the present invention.

[0041] Figure 7 This is a partially enlarged structural diagram of the coordination between the tensioning member, the lower transverse support member, and the upper tensioning anchoring assembly in an embodiment of the present invention.

[0042] Figure 8 This is a schematic diagram of the structure of the concrete hollow slab beam bridge reinforcement system based on bridge deck truss prestressing in an embodiment of the present invention.

[0043] Figure 9 This is a flowchart illustrating the reinforcement method for concrete hollow slab beam bridges based on prestressed bridge deck trusses, according to an embodiment of the present invention.

[0044] In the diagram, 1 is a concrete hollow slab beam bridge, 11 is a hollow slab beam, 12 is a joint between slabs, 13 is the bridge deck pavement layer, 14 is the existing concrete guardrail, 15 is the cantilever section on the outer side of the edge slab, 16 is the cap beam, and 17 is the pier; 2 is the bridge deck reaction truss, 21 is the upper chord, 22 is the lower chord, 23 is the diagonal web member, and 24 is the vertical cable-passing tube; 3 is the bridge deck anchorage assembly; 4 is the tensioning member; 5 is the lower transverse support member; 6 is the upper tensioning anchorage assembly, 61 is the upper bearing plate, and 62 is the upper anchor; 7 is the lower anchorage head; and 8 is the lower anti-detachment plate. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0046] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0047] Example 1

[0048] This embodiment provides a reinforcement method for concrete hollow slab beam bridges based on bridge deck truss prestressing, applicable to the reinforcement construction of existing concrete hollow slab beam bridge 1.

[0049] like Figure 1 and Figure 2As shown, the existing hollow concrete slab beam bridge 1 consists of multiple hollow slab beams 11 arranged side by side along the transverse direction of the bridge. Joints 12 are formed between adjacent hollow slab beams 11. A bridge deck pavement layer 13 is laid on top of the hollow slab beams 11. Existing concrete guardrails 14 are installed on both sides of the bridge. An outer cantilever section 15 is formed on the outer side of the outermost hollow slab beam 11. The superstructure of the bridge is supported by a cap beam 16, which connects to piers 17. Under the combined effects of long-term vehicle loads, environmental erosion, and aging of the bridge deck's ancillary structures, this type of bridge is prone to defects such as mid-deck subsidence, cracking of the joints 12 between slab beams, and cracking of individual hollow slab beams 11. For bridges with significant height, complex terrain beneath the bridge, or limited construction conditions, the construction method of erecting a platform under the bridge and implementing underpinning, support, or reinforcement typically presents significant challenges, high risks, and long construction periods.

[0050] The reinforcement method in this embodiment establishes a prestressed reaction system on the bridge deck and a transverse support system at the bridge bottom. The reaction force on the bridge deck is transferred to the bridge bottom through vertical tensioning members, so that the bridge cross section obtains an overall upward support effect. This method can be implemented locally in areas with concentrated defects, or multiple sets of reinforcement units can be set along the longitudinal direction of the same bridge span. If necessary, it can also be continuously arranged along the entire span or multiple spans.

[0051] See Figure 9 During the actual construction, the existing concrete guardrails 14 on both sides of the bridge will be removed first, such as... Figure 3 As shown. The existing concrete guardrail 14 can be removed along the entire longitudinal direction of the bridge, or it can be removed in sections at intervals depending on traffic organization conditions and construction pace. After removal, the outer cantilever section 15 of the outermost hollow slab beam 11 will be exposed, thus forming the installation work area on both sides of the bridge deck. For cases where there are local defects, honeycomb pitting, loose layers, or surface contamination on the surface of the outer cantilever section 15, cleaning, repair, and necessary local repairs can be carried out first to ensure the connection quality of the subsequent anchorage parts.

[0052] like Figure 4 and Figure 5As shown, bridge deck reaction trusses 2 are installed on both sides of the bridge deck. The bridge deck reaction trusses 2 are arranged longitudinally along the bridge and include an upper chord 21, a lower chord 22, diagonal web members 23, and vertical cable-stayed tubes 24. The upper chord 21 and lower chord 22 constitute the upper and lower main members of the bridge deck reaction trusses 2, respectively. Multiple diagonal web members 23 are arranged between the upper chord 21 and lower chord 22, forming a continuous truss unit. The vertical cable-stayed tubes 24 are preferably arranged at or near the truss nodes to improve the local stiffness and overall stability when the tension load is transferred to the bridge deck reaction trusses 2. The bridge deck reaction trusses 2 can be a welded integral structure or a segmented structure prefabricated in the factory and assembled on site. When the bridge width is large, transportation conditions are limited, or the construction site is narrow, a segmented structure can be used; when it is necessary to improve the overall stiffness and reduce on-site connection nodes, a welded integral structure can be used.

[0053] The bridge deck reaction truss 2 is connected to the original bridge via a bridge deck anchoring assembly. The bridge deck anchoring assembly includes a connecting base plate, anchor bolts, and stiffening plates. The connecting base plate is located at the bottom of the bridge deck reaction truss 2. The anchor bolts pass through the connecting base plate and are anchored into the outer cantilever section 15 of the side plate and its inner concrete structure. The stiffening plates are connected between the bridge deck reaction truss 2 and the connecting base plate. Through the bridge deck anchoring assembly, the bridge deck reaction truss 2 is stably fixed to the original bridge structure. The bridge deck reaction truss 2 is fixed to the outer cantilever section 15 of the side plate and its inner bridge deck structure via the bridge deck anchoring assembly, and forms a stable truss system through the upper chord 21, lower chord 22, and diagonal web members 23 to ensure overall stiffness and lateral stability during tensioning. If necessary, stiffening or limiting components can be added at local nodes of the bridge deck reaction truss 2 on one side to improve the local stability of the bridge deck reaction truss 2 during tensioning.

[0054] like Figures 6-8 As shown, a lower transverse support member 5 is installed at the bottom of the bridge. The lower transverse support member 5 extends transversely along the bridge and is located below the bottom of multiple hollow slab beams 11 to provide transverse overall support for the hollow slab beams 11. In this embodiment, the lower transverse support member 5 is a square tube; in other embodiments, the lower transverse support member 5 can also be a box girder, I-beam, channel beam, or composite support beam. The placement of the lower transverse support member 5 corresponds to the location of bridge defects, with priority given to areas such as the mid-slope subsidence zone, the cracked area of ​​the inter-slab joint 12, and areas with concentrated single-slab cracks. When the defect area is small, it can be installed locally; when the defect area is large, multiple lower transverse support members 5 can be installed longitudinally along the same bridge span. To improve the contact condition, steel pads, rubber pads, or metal pads can be installed between the lower transverse support member 5 and the bottom of the hollow slab beam 11.

[0055] The tensioning member 4 is vertically arranged and passes through the vertical cable-passing tube 24. The tensioning member 4 can be made of steel cable, steel strand, or high-strength tie rod. In this embodiment, the tensioning member 4 is preferably made of steel strand. After the lower end of the tensioning member 4 passes downward through the connecting hole on the lower transverse support member 5, a lower anchoring head 7 is installed on the lower side of the lower transverse support member 5, and a lower anti-detachment plate 8 is provided on the lower anchoring head 7. The outer dimensions of the lower anti-detachment plate 8 are larger than the size of the connecting hole. After the lower anchoring head 7 and the lower anti-detachment plate 8 are engaged, the tensioning member 4 is anchored to the lower side of the lower transverse support member 5. Depending on the local stress conditions and the component processing method, a shim or pad can also be provided between the lower anchoring head 7 and the lower anti-detachment plate 8 to improve the local pressure state.

[0056] The upper end of the tensioning member 4 protrudes from the top of the vertical cable-passing tube 24 and connects to the upper tensioning anchoring assembly 6. The upper tensioning anchoring assembly 6 includes an upper bearing plate 61 located at the top of the vertical cable-passing tube 24 and an upper anchor 62 located above the upper bearing plate 61. During construction, a tension force is applied to the upper end of the tensioning member 4 using jacks. After reaching the predetermined tension force, the tensioning member 4 is locked by the upper anchor 62, and the tension force is transferred to the bridge deck reaction truss 2 by means of the upper bearing plate 61. The tensioning method can be point-by-point graded tensioning or left-right symmetrical synchronous tensioning; when the transverse defects of the bridge deck are unevenly distributed, zoned and staged tensioning can also be used to more finely adjust the bearing force distribution of each tensioning point.

[0057] Once the tensioning member 4 reaches its design tension and locks in place, the lower transverse support member 5 moves upward under the action of the tensioning member 4 and presses against the bottom of the hollow slab beam 11, providing continuous upward transverse support to the multiple hollow slab beams 11. As a result, the overall stress state of the bridge cross-section is improved, the tendency for the bridge deck to sink in the middle is reduced, the uneven stress and deformation differences at the joints 12 between the slabs are alleviated, and the degree of local stress concentration in a single hollow slab beam 11 is correspondingly reduced. For bridges with existing cracks, before and after the completion of the overall reinforcement, crack sealing, grouting, or local repairs can be carried out based on the crack width and severity.

[0058] After reinforcement, the bridge deck reaction truss 2 is permanently retained along both sides of the bridge deck. Since the top of the bridge deck reaction truss 2 is higher than the surface of the bridge deck pavement layer 13, and it is continuously or segmented along the longitudinal direction of the bridge, the bridge deck reaction truss 2 forms a protective boundary on the bridge side after reinforcement, replacing the protective function of the original existing concrete guardrail 14. For bridges with higher protection levels or additional landscape requirements, protective panels, protective nets, or auxiliary railing structures can also be added to the outside of the bridge deck reaction truss 2.

[0059] In this embodiment, the quantity, specifications, spacing, and cross-sectional dimensions of the bridge deck reaction truss 2, bridge deck anchorage components, tensioning members 4, lower transverse support components 5, and upper tensioning and anchoring components 6 can be determined according to the bridge span, bridge width, degree of damage, and design load-bearing requirements. The bridge deck reaction truss 2 can be arranged only in the area of ​​concentrated damage or continuously along the entire span; the lower transverse support components 5 can be provided in one or multiple places; the quantity and spacing of the tensioning members 4 can be determined according to the support range and stress requirements.

[0060] Example 2

[0061] This embodiment provides a reinforcement device for a concrete hollow slab beam bridge based on prestressed bridge deck trusses. The reinforcement device is installed on an existing concrete hollow slab beam bridge 1, forming a reaction system on both sides of the bridge deck and a support system at the bottom of the bridge. The two are connected as one unit by tensioning members 4 to form a permanent reinforcement structure.

[0062] like Figure 1 , Figure 4 , Figure 6 and Figure 7 As shown, the reinforcement device includes a bridge deck reaction truss 2, a bridge deck anchoring assembly, tension members 4, a lower transverse support member 5, and an upper tensioning and anchoring assembly 6. The bridge deck reaction truss 2 is located longitudinally along both sides of the bridge deck, and its main body includes an upper chord 21, a lower chord 22, diagonal web members 23, and vertical cable-passing tubes 24. The upper chord 21, lower chord 22, and diagonal web members 23 together form a continuous truss load-bearing unit. The vertical cable-passing tubes 24 are located at or near the truss nodes, forming a guide channel for the tension members 4. The bridge deck reaction truss 2 can be a steel structure, taking into account component stiffness, self-weight control, and ease of on-site installation. If necessary, an anti-corrosion coating or protective layer can be applied to the surface of the bridge deck reaction truss 2 to improve its durability under long-term service conditions.

[0063] The bridge deck anchorage assembly is located at the connection point between the bridge deck reaction truss 2 and the original bridge. It may include a connecting base plate, anchor bolts, and stiffening plates. The connecting base plate is located at the bottom node area of ​​the bridge deck reaction truss 2. The anchor bolts pass through the connecting base plate and are anchored into the outer cantilever section 15 of the side plate and its inner concrete structure. The stiffening plate is located between the bridge deck reaction truss 2 and the connecting base plate to improve the overall stiffness of the connection node. Through this connection system, the bridge deck reaction truss 2 can stably bear the reaction force after the tensioning member 4 is locked, and is less prone to slippage, warping, or lateral instability.

[0064] The tensioning member 4 is inserted into the vertical cable-passing tube 24, with its upper end connected to the upper tensioning anchor assembly 6 and its lower end connected to the lower transverse support member 5. The upper tensioning anchor assembly 6 includes an upper pressure plate 61 and an upper anchor 62. The upper pressure plate 61 is located at the top of the vertical cable-passing tube 24, and the upper anchor 62 is positioned above the upper pressure plate 61. After the upper end of the tensioning member 4 passes through the upper pressure plate 61 and the upper anchor 62, it is locked. The upper pressure plate 61 bears the local pressure after tensioning and locking, and transfers the load to the bridge deck reaction truss 2. If necessary, a protective cover, rain cover, or anti-loosening component can also be installed on the outside of the upper tensioning anchor assembly 6 to improve reliability under long-term service conditions.

[0065] The lower transverse support member 5 is located at the bottom of the bridge, extending laterally along the bridge and situated below the bottom of at least two adjacent hollow slab beams 11. In this embodiment, the lower transverse support member 5 is a square tube; in other embodiments, box girders, I-beams, channel beams, or combined support beams may be used depending on the bridge width, support length, and stress requirements. The lower transverse support member 5 is provided with connecting holes. After the lower end of the tension member 4 passes through the connecting holes, a lower anchor head 7 and a lower anti-detachment plate 8 are provided on the lower side of the lower transverse support member 5. The lower anchor head 7 and the lower anti-detachment plate 8 together constitute the lower end anchoring structure, enabling the tension member 4 to stably transmit the tension to the lower transverse support member 5 in the locked state. Depending on the component cross-sectional dimensions, orifice shape, and local bearing pressure requirements, a gasket or pad may also be configured between the lower anchor head 7 and the lower anti-detachment plate 8.

[0066] The lower transverse support member 5 can form line contact or surface contact with the bottom of the hollow slab beam 11. To obtain a more uniform stress state, steel pads, rubber pads, or metal pads can be installed between the lower transverse support member 5 and the bottom of the hollow slab beam 11. When there are local unevenness at the bottom of the bridge or slight differences in the bottom elevation of different slab beams, the above-mentioned pad structure can also take into account local leveling and stress dispersion. For areas with minor damage, the lower transverse support member 5 can use a smaller cross section and reduce the number of support members; for areas with severe damage, the overall bearing capacity can be improved by increasing the number of lower transverse support members 5, increasing the specifications of the tensioning members 4, or reducing the spacing between tensioning points.

[0067] In this embodiment, the reinforcement device forms a clear force transmission path: the bridge deck reaction truss 2 bears the side reaction force of the bridge deck, the upper tensioning anchor component 6 locks the tensioning member 4, the tensioning member 4 vertically transmits the reaction force to the lower transverse support member 5, and the lower transverse support member 5 then applies the support force to the bottom of the adjacent hollow slab beam 11. Through this force transmission path, the bridge deck structure and the bridge bottom support member form an integrated linkage, which can not only improve the overall stress state in the cross-sectional direction of the bridge, but also reduce the need for a large-scale construction platform under the bridge, which is especially suitable for high-pier bridges, deep-ditch bridges, and existing bridges with limited construction conditions under the bridge.

[0068] After the reinforcement device is installed, the bridge deck reaction truss 2 is permanently retained along the outer side of the bridge deck, with its top exceeding the bridge deck pavement layer 13 and forming a bridge side protection boundary. The bridge deck reaction truss 2 serves both to bear reaction forces and maintain the permanent reinforcement state, while also providing bridge side protection. Depending on the collision protection level, aesthetic effects, and maintenance needs of different bridges, protective panels, protective netting, auxiliary railings, or maintenance accessories can also be attached to the outer side of the bridge deck reaction truss 2.

[0069] In this embodiment, the materials of each newly added component can be determined according to the engineering environment. The bridge deck reaction truss 2, the bridge deck anchorage assembly, and the lower transverse support component 5 can be made of ordinary structural steel, weathering steel, or steel components treated with anti-corrosion; the tensioning member 4 can be made of steel cable, steel strand, or high-strength tie rod; the upper tensioning anchorage assembly 6 and the lower anchorage structure should be protected against corrosion, loosening, and water damage. For hollow slab beam bridges with different bridge widths, different spans, and different levels of damage, the reinforcement device parameter configuration adapted to the original bridge structure can be formed by adjusting the height of the bridge deck reaction truss 2, the length of the truss section, the spacing of the vertical cable-passing pipes 24, the specifications of the tensioning member 4, and the cross-sectional dimensions of the lower transverse support component 5.

[0070] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A method for strengthening concrete hollow slab beam bridges based on prestressed bridge deck trusses, characterized in that, Includes the following steps: Remove the existing concrete guardrail to expose the outermost cantilever section of the outermost hollow slab beam. Bridge deck reaction trusses are installed on both sides of the bridge deck. The bridge deck reaction trusses include an upper chord, a lower chord, diagonal web members, and vertical cable-passing tubes. The bridge deck reaction trusses are fixed to the cantilever section on the outer side of the side plate by means of bridge deck anchoring components. A lower transverse support member is installed at the bottom of the bridge. The lower transverse support member extends laterally along the bridge and is located below the bottom of multiple hollow slab beams. The tensioning member is inserted into the vertical cable-passing tube from top to bottom. After the lower end of the tensioning member passes through the connecting hole on the lower transverse support member, the lower anchor head and the lower anti-detachment plate are installed on the lower side of the lower transverse support member. The upper end of the tensioning member passes through the top of the vertical cable-passing tube. Install the upper tensioning anchor component at the top of the vertical cable-passing pipe, apply tension force to the upper end of the tensioning member using a jack, and lock the tensioning member using the upper tensioning anchor component after the predetermined tension force is reached. Once locked, the tensioning member remains under tension, while the lower transverse support member moves upward and presses against the bottom of the multiple hollow slab beams. The bridge deck reaction trusses are retained along both sides of the bridge deck, with the top of the bridge deck reaction trusses higher than the surface of the bridge deck pavement, forming a protective boundary on the bridge side.

2. The method for strengthening concrete hollow slab beam bridges based on prestressed bridge deck trusses according to claim 1, characterized in that, The existing concrete guardrails are removed along the entire longitudinal section of the bridge, or removed in sections along the longitudinal section of the bridge; the bridge deck reaction trusses and lower transverse support components are set in the corresponding middle subsidence area of ​​the bridge deck, the joint cracking area between slabs, or the cracking area of ​​a single hollow slab beam; one or more sets of bridge deck reaction trusses and lower transverse support components are provided along the longitudinal section of the bridge within the same bridge span.

3. The method for strengthening concrete hollow slab beam bridges based on prestressed bridge deck trusses according to claim 1, characterized in that, The upper chord, lower chord, and diagonal web members form a continuous truss unit. The vertical cable-passing tubes are located at or near the truss nodes. The bridge deck reaction truss is a welded integral structure or a segmented structure prefabricated in the factory and assembled on site. Stiffening or limiting components are provided at some nodes of the bridge deck reaction truss.

4. The method for strengthening concrete hollow slab beam bridges based on prestressed bridge deck trusses according to claim 1, characterized in that, The bridge deck anchoring assembly includes a connecting base plate, anchor bolts, and stiffening plates; the connecting base plate is located at the bottom of the bridge deck reaction truss, the anchor bolts pass through the connecting base plate and are anchored into the outer cantilever section of the side plate, and the stiffening plates connect the bridge deck reaction truss and the connecting base plate.

5. The method for strengthening concrete hollow slab beam bridges based on prestressed bridge deck trusses according to claim 1, characterized in that, The tensioning member is a steel cable, steel strand, or high-strength tie rod; the upper tensioning and anchoring assembly includes an upper pressure plate and an upper anchor, the upper pressure plate is located at the top of the vertical cable-passing pipe, and the upper anchor is located above the upper pressure plate; the lower anchor head and the lower anti-detachment plate are located on the lower side of the lower transverse support member; a gasket or pad is provided between the lower anchor head and the lower anti-detachment plate.

6. The method for strengthening concrete hollow slab beam bridges based on prestressed bridge deck trusses according to claim 1, characterized in that, The lower transverse support member is a square tube, box beam, I-beam, channel beam or composite support beam; steel pads, rubber pads or metal pads are provided between the lower transverse support member and the bottom of several hollow slab beams; one or more lower transverse support members are provided in the same bridge span.

7. A reinforcement system for concrete hollow slab beam bridges based on prestressed bridge deck trusses, characterized in that, Including concrete hollow slab beam bridges, bridge deck reaction trusses, bridge deck anchorage components, tensioning components, lower transverse support components, upper tensioning and anchoring components, and lower anchorage heads; The concrete hollow slab beam bridge includes multiple hollow slab beams arranged side by side along the transverse direction of the bridge, with joints formed between adjacent hollow slab beams, and an outer cantilever section formed on the outer side of the outermost hollow slab beam. The bridge deck reaction truss is provided in at least two sets, and the two sets of bridge deck reaction trusses are respectively provided on both sides of the bridge deck. The bridge deck reaction truss is fixed to the cantilever section on the outer side of the side plate by the bridge deck anchoring assembly. The lower transverse support member extends laterally along the bridge and is located below the bottom of the multiple hollow slab beams; The tensioning member is vertically inserted into the bridge deck reaction truss, and the lower end of the tensioning member passes through the lower transverse support member and is connected to the lower anchor head. After the upper end of the tensioning member passes through the upper part of the bridge deck reaction truss, it is connected to the upper tensioning anchoring assembly. When the tensioning member is in the tensioning locked state, the lower transverse support member presses against the bottom of the multiple hollow slab beams.

8. The reinforcement system for concrete hollow slab beam bridges based on prestressed bridge deck trusses according to claim 7, characterized in that, The bridge deck reaction truss includes an upper chord, a lower chord, diagonal web members, and vertical cable-stayed tubes. The upper chord, lower chord, and diagonal web members of the bridge deck reaction truss together form a continuous truss unit. The vertical cable-stayed tubes are located at or near the truss nodes. The tensioning members are installed inside the vertical cable-stayed tubes.

9. The reinforcement system for concrete hollow slab beam bridges based on prestressed bridge deck trusses according to claim 7, characterized in that, The bridge deck anchoring assembly includes a connecting base plate, anchor bolts, and stiffening plates; the upper tension anchoring assembly includes an upper bearing plate and an upper anchor; and a lower anti-detachment plate is provided between the lower anchor head and the lower transverse support member.

10. The reinforcement system for concrete hollow slab beam bridges based on prestressed bridge deck trusses according to claim 7, characterized in that, The bridge deck reaction truss is set in the middle of the bridge deck sinking area, the inter-slab joint cracking area, or the cracking area of ​​a single hollow slab beam; one or more sets of bridge deck reaction trusses are set along the longitudinal direction of the bridge within the same span; corresponding to each set of bridge deck reaction trusses, one or more lower transverse support members are set at the bottom of the bridge; the outer side of the bridge deck reaction truss is provided with a protective panel, protective net, or auxiliary railing structure.

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