Bridge self-stress hollow slab structure and construction method thereof

Abstract

The self-stress hollow slab structure of the bridge comprises a hollow slab and a self-stress rigid connection beam, the hollow slab is composed of a self-stress bottom plate, two thin rib plates and a top plate, and the self-stress rigid connection beam is poured above the extending parts of the two adjacent bottom plates; the self-stress rigid connection beam is composed of micro-expansion concrete, a rigid connection beam longitudinal rib, a rigid connection beam stirrup, a left single-limb rib, a right single-limb rib, two adjacent lower inclined steel bar extending parts and two adjacent upper inclined steel bar extending parts. The construction method comprises the following steps: a) welding the expansion plates and the longitudinal self-stress ribs; b) pouring high-expansion concrete; c) supporting an inner template of the hollow slab; d) pouring common concrete; e) binding a steel reinforcement framework of the self-stress rigid connection beam; and (f) micro-expansive concrete is poured. According to the bridge self-stress hollow slab structure and the construction method thereof, rigid connection between the hollow slab and the self-stress rigid connection beam is achieved, the situation that a single hollow slab is stressed is avoided, and the service life of the hollow slab is prolonged.

Description

Technical Field

[0001] The invention relates to a bridge self-stressed hollow slab structure and a construction method thereof, and more specifically, to a bridge self-stressed hollow slab structure in which adjacent hollow slabs are rigidly connected via a self-stressed rigid beam and a construction method thereof. Background Art

[0002] With the rapid development of my country's economy, the mileage of highways supporting economic development is getting longer and longer. In the process of road construction, in order to protect the ecological environment along the road as much as possible, bridges that are convenient for water, humans and animals to cross will be built when passing through rivers, mountain streams or areas where animals migrate frequently. At present, the commonly used road bridges are hollow slab bridges within 20 meters. Hollow slab bridges are formed by pile foundations, cap beams and hollow slabs laid on the cap beams. Because the hollow slabs are prefabricated, hollow slab bridges have the advantages of standardized production, high quality, and low cost of large-scale production.

[0003] Since the adjacent hollow slabs laid on the cap beam are connected by hinged joints, the hinged joints are easily damaged during the service life of the hollow slab bridge. Once the hinged joints are damaged, the hollow slab will be subjected to stress on a single slab. The stress on a single slab will shorten the life of the hollow slab bridge and fail to reach the designed service life. At the same time, affected by the stress characteristics of the hollow slab bridge, the hollow slab is pulled near the lower surface, which makes cracks at the bottom of the hollow slab easy to appear. Once cracks appear at the bottom of the hollow slab, it is very difficult to maintain, which further aggravates the damage of the hollow slab. Summary of the invention

[0004] In order to overcome the disadvantages of the above technical problems, the present invention provides a bridge self-stressed hollow slab structure and a construction method thereof.

[0005] The self-stressed hollow slab structure of the bridge of the present invention comprises a hollow slab and a self-stressed rigid beam for connecting two adjacent hollow slabs, the two ends of the hollow slab are laid on the cap beam of the bridge, the hollow slab is composed of a self-stressed bottom slab, two thin ribs and a top slab, the two sides of the top slab are connected to the self-stressed bottom slab via the two thin ribs, and a hollow cavity is formed between the bottom slab, the two thin ribs and the top slab; the characteristic is that: the two sides of the self-stressed bottom slab are bottom slab extensions extending out of the outer side surfaces of the thin ribs, and the bottom slab extensions are pre-embedded with vertical single-limb anchor bars exposed on their upper surfaces; the self-stressed bottom slab is evenly provided with bottom slab transverse connecting steel bars extending out of the outer side surfaces of the thin ribs, and the extending parts of the bottom slab transverse connecting steel bars form upward oblique steel bar extensions, and the top slab is evenly provided with top slab transverse connecting steel bars extending out of its outer side surfaces, and the extending parts of the top slab transverse connecting steel bars form downward oblique steel bar extensions; the self-stressed rigid beam is cast above the two adjacent bottom slab extensions; The self-stressed rigid beam is composed of micro-expansive concrete and the longitudinal reinforcement of the rigid beam, the stirrups of the rigid beam, the left single-leg reinforcement, the right single-leg reinforcement, the two adjacent downward inclined steel bar extensions and the two adjacent upward inclined steel bar extensions cast therein. The stirrups of the rigid beam are rectangular and evenly distributed along the length direction of the self-stressed rigid beam. The stirrups of the rigid beam are tied to the longitudinal reinforcement of the rigid beam; the lower ends of the left single-leg reinforcement and the right single-leg reinforcement are welded to the single-leg reinforcement anchoring reinforcement, and the upper ends are tied to the longitudinal reinforcement of the rigid beam; the two adjacent downward inclined steel bar extensions and the two adjacent upward inclined steel bar extensions are welded.

[0006] The self-stressed hollow slab structure of the bridge of the present invention comprises a self-stressed bottom slab composed of high-expansion concrete, longitudinal self-stressed tendons, self-stressed tendon stirrups, bottom slab transverse connecting steel bars and expansion plates, the self-stressed tendon stirrups are rectangular, the self-stressed tendon stirrups and the bottom slab transverse connecting steel bars are evenly arranged in the length direction of the self-stressed bottom slab, the self-stressed tendon stirrups are tied to the longitudinal self-stressed tendons, the expansion plates are arranged at both ends of the self-stressed bottom slab, and the two ends of the longitudinal self-stressed tendons are welded to the expansion plates.

[0007] The self-stressed hollow slab structure of the bridge of the present invention comprises a top slab composed of ordinary concrete and top slab transverse ribs, top slab longitudinal ribs and top slab transverse connecting steel bars cast therein, the top slab longitudinal ribs are evenly arranged in the width direction of the top slab, and the top slab transverse ribs and top slab transverse connecting steel bars are evenly arranged in the length direction of the top slab.

[0008] The bridge self-stressed hollow slab structure of the present invention comprises a thin ribbed slab composed of ordinary concrete and thin ribbed slab longitudinal reinforcement and shear steel bars cast therein, the length direction of the thin ribbed slab longitudinal reinforcement is consistent with the length direction of the thin ribbed slab, and the shear steel bars are gradually denser from the middle to both ends in the length direction of the thin ribbed slab; the lower end of the shear steel bars is tied to the longitudinal self-stressed reinforcement, the upper end of the shear steel bars is tied to the longitudinal reinforcement of the top plate, and the thin ribbed slab longitudinal reinforcement is tied to the shear steel bars.

[0009] The self-stressed hollow slab structure of the bridge of the present invention is characterized in that the self-stressed rigid beam is provided with upper, middle and lower rows of rigid beam longitudinal reinforcements, the outward extension parts of two adjacent lower oblique reinforcements are passed through the longitudinal reinforcements of the upper row of rigid beams and then welded and connected, and the outward extension parts of two adjacent upper oblique reinforcements are passed through the longitudinal reinforcements of the lower row of rigid beams and then welded and connected; the self-stressed bottom plate is provided with upper and lower rows of longitudinal self-stressed reinforcements, the lower ends of the single-limb reinforcement anchor reinforcements are tied and connected to the longitudinal self-stressed reinforcements in the lower row, the lower ends of the shear reinforcements are tied and connected to the longitudinal self-stressed reinforcements in the lower row, and the transverse connecting reinforcements of the bottom plate are located between the upper row of longitudinal self-stressed reinforcements and the lower row of self-stressed reinforcements; the left single branch reinforcement and the right single branch reinforcement are gradually denser from the middle to the two ends in the length direction of the self-stressed rigid beam, and the stirrups of the rigid beam are evenly distributed in the length direction of the self-stressed rigid beam.

[0010] The bridge self-stressed hollow slab structure of the present invention has a slab bottom joint between the bottom slab extensions of two adjacent hollow slabs, the width of the slab bottom joint is 2 cm, and slightly expanded fine stone concrete is poured in the slab bottom joint, and the grade of the slightly expanded fine stone concrete is 40MPa~45MPa; hollow slab heads formed by concrete pouring are arranged at both ends of the hollow cavity of the hollow slab.

[0011] The self-stressed hollow slab structure of the bridge of the present invention has a length of 10m-13m, a width of 98cm-123cm, and a height of 60cm-80cm; a width of the self-stressed bottom plate of 98cm-123cm, a thickness of 12cm-15cm, and a length of 10m-13m; a thickness of the thin rib plate of 8cm-9cm, a thickness of the top plate of 10cm-12cm, a width of the self-stressed rigid beam of 26cm-30cm, and a thickness of the expansion plate of 1.5cm-2.0cm; The spacing between adjacent top plate transverse connecting steel bars and adjacent bottom plate transverse connecting steel bars is 15cm~25cm, and the spacing between adjacent rigid beam stirrups is 15cm~25cm.

[0012] The bridge self-stressed hollow slab structure of the present invention, the longitudinal self-stressed reinforcement adopts HRB400 steel bars with a diameter of 16mm-25mm, the bottom plate transverse connecting reinforcement and the top plate transverse connecting reinforcement both adopt HRB335 steel bars with a diameter of 16mm-22mm, and the single-limb reinforcement anchoring reinforcement, shear reinforcement, thin ribbed longitudinal reinforcement, and top plate longitudinal reinforcement all adopt HRB335 steel bars with a diameter of 12mm-14mm; After high-expansion concrete solidifies, the self-stress value generated in the longitudinal direction of the self-stress base plate is 5MPa~7MPa, while that of ordinary concrete and micro-expansion concrete is 40MPa~45MPa.

[0013] The construction method of the bridge self-stressed hollow slab structure of the present invention is characterized by being achieved through the following steps: a). First, weld the expansion plate and longitudinal self-stressing reinforcement on the precast bottom form of the hollow slab, and then tie the self-stressing reinforcement stirrups, shear reinforcement, bottom slab transverse connecting reinforcement, single-leg reinforcement anchoring reinforcement and thin ribbed longitudinal reinforcement; b). Then, support the outer formwork of the hollow slab, and then pour high expansion concrete to form a self-stressed bottom slab, and water cure for 7 days; c). Then, support the inner formwork of the hollow slab and tie the top slab transverse reinforcement, top slab longitudinal reinforcement and top slab transverse connecting reinforcement; d). Then, ordinary concrete is poured to form thin ribbed slabs and top slabs in sequence. After the outer and inner formworks of the hollow slab are removed, the entire hollow slab is watered and cured for 7 days; e). Then, install the hollow slab on the bridge cap beam, and pour the micro-expansion fine stone concrete in the slab bottom joint between the bottom slab extensions of two adjacent hollow slabs; then, weld the lower ends of the left and right single-leg reinforcements to the upper ends of the single-leg reinforcement anchoring reinforcements, weld the two top slab transverse connecting steel bars and the two bottom slab transverse connecting steel bars, and then tie the rigid beam longitudinal reinforcement to the rigid beam stirrups to form a steel skeleton of the self-stressed rigid beam; f). Finally, pour micro-expansive concrete on the top of the extended part of the bottom plate of the two adjacent hollow slabs, sprinkle water and cure for 7 days, and finally form the self-stressed hollow slab structure of the bridge.

[0014] In the construction method of the bridge self-stressed hollow slab structure of the present invention, the dosage of the expansion agent in the micro-expansion concrete is 5%-8%.

[0015] The beneficial effects of the present invention are as follows: the self-stressed hollow slab structure of the bridge and the construction method thereof of the present invention, two adjacent hollow slabs on the bridge cap beam are connected via a self-stressed rigid beam, the hollow slab is composed of a self-stressed bottom plate, a thin rib plate and a top plate, the two sides of the self-stressed bottom plate are bottom plate extensions, the self-stressed rigid beam is cast above the bottom plate extensions of the two adjacent hollow slabs, the extensions of the bottom plate transverse connecting steel bars (i.e., the upper inclined steel bar extensions) in the two adjacent self-stressed bottom plates are welded and cast in the self-stressed steel beam, the extensions of the top plate transverse connecting steel bars (i.e., the lower inclined steel bar extensions) in the two adjacent top plates are welded and cast in the self-stressed rigid beam; the self-stressed rigid beam is provided with rigid beam longitudinal bars, rigid beam stirrups and left and right single-limb bars, and the lower ends of the left and right single-limb bars are welded to the upper ends of the single-limb bar anchor bars. In this way, by casting a self-stressed rigid beam with built-in longitudinal reinforcement, stirrups and left and right single-leg reinforcement above the overhanging part of the adjacent bottom plates, the upper structure of the hollow slab bridge has good rigidity in the transverse direction, and the shear area of ​​the self-stressed hollow slab structure of the bridge is increased; at the same time, the overhanging parts of the adjacent top plate transverse connecting steel bars and the bottom plate transverse connecting bars are welded and cast in the self-stressed rigid beam, and the single-leg reinforcement anchoring bars welded with the left and right single-leg reinforcements are cast in the self-stressed bottom plate, thereby realizing a rigid connection between the hollow plate and the self-stressed rigid beam, so that the adjacent hollow plates and the self-stressed rigid beams between them are subjected to the same force, and a single hollow plate will not be subjected to force, thereby extending the service life of the hollow plate.

[0016] Furthermore, the bottom plate constituting the hollow slab adopts a self-stressed bottom plate, and no tensioning or grouting is required for on-site construction. The process is simple and the cost is low. Therefore, it is also suitable for use in projects with inconvenient transportation and narrow construction sites.

[0017] Furthermore, the side plates constituting the hollow slabs are thin rib plates, which, compared with the existing prestressed hollow slabs, do not increase the weight of the bridge superstructure while ensuring the bearing capacity.

[0018] Furthermore, for the existing hollow slabs connected by hinged joints, the bridge deck pavement layer above it often needs to be made 15 cm thick. However, after adopting the bridge self-stressed hollow slab structure of the present invention, the pavement layer can be made 10 cm thick, which reduces the weight of the bridge and saves the project cost.

[0019] Furthermore, the self-stressed base plate that constitutes the hollow slab is cast with high-expansion concrete. If cracks appear on the bottom of the hollow slab, water can be sprinkled so that the moisture will react chemically with the expansion agent in the self-stressed base plate that has not yet reacted chemically, and the cracks on the bottom of the slab can heal automatically, solving the national problem of the difficulty in maintaining cracks on the bottom of bridge slabs.

[0020] Furthermore, the high expansion concrete has few dense pores after solidification, making the longitudinal self-stress reinforcement, self-stress reinforcement stirrups and bottom plate transverse connecting steel bars inside it less likely to rust, further extending the service life of the hollow slab. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 , Figure 2 They are all structural schematic diagrams of the bridge self-stressed hollow slab structure of the present invention; Figure 3 It is a structural schematic diagram of the hollow slab in the bridge self-stressed hollow slab structure of the present invention.

[0022] In the figure: 1 self-stressed bottom plate, 2 thin ribbed plate, 3 top plate, 4 self-stressed rigid beam, 5 expansion plate, 6 longitudinal self-stressed reinforcement, 7 self-stressed reinforcement stirrups, 8 high expansion concrete, 9 top plate transverse connecting reinforcement, 10 bottom plate transverse connecting reinforcement, 11 single-leg reinforcement anchoring reinforcement, 12 shear reinforcement, 13 thin ribbed plate longitudinal reinforcement, 14 ordinary concrete, 15 top plate transverse reinforcement, 16 top plate longitudinal reinforcement, 17 hollow plate capping, 18 left single-leg reinforcement, 19 right single-leg reinforcement, 20 rigid beam longitudinal reinforcement, 21 rigid beam stirrups, 22 slightly expansive concrete, 23 plate bottom joint, 24 bottom plate extension, 25 hollow cavity, 26 lower inclined reinforcement extension, 27 upper inclined reinforcement extension. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] like Figure 1 and Figure 2 As shown in the figure, the structural schematic diagrams of the bridge self-stressed hollow slab structure of the present invention are given. Figure 3A structural schematic diagram of a hollow slab is given. The self-stressed hollow slab structure of the bridge shown is composed of a hollow slab and a self-stressed rigid beam 4 arranged between two adjacent hollow slabs. The two ends of the hollow slab are arranged on the cap beam of the bridge. The self-stressed rigid beam 4 is cast between the two adjacent hollow slabs to achieve a rigid connection between the two adjacent hollow beams. The hollow slab shown is composed of a self-stressed bottom plate 1, two thin ribs 2 and a top plate 3. Both sides of the top plate 3 are connected to the self-stressed bottom plate 1 through the thin ribs 2 to form an integrated hollow slab structure. A hollow cavity 25 is formed between the self-stressed bottom plate 1, the two thin ribs 2 and the top plate 3. The setting of the hollow cavity 25 can effectively reduce the weight of the hollow slab and increase its bearing capacity. The cross section of the hollow cavity 25 is usually designed to be an unequally symmetrical hexagonal shape.

[0025] The two sides of the self-stressed bottom plate 1 extend out of the outer side of the thin ribbed plate 2, and the extended part of the self-stressed bottom plate 1 forms a bottom plate extended part 24, and the self-stressed rigid beam 4 is cast above the two adjacent bottom plate extended parts 24. Vertical single-leg anchor bars 11 are cast in the bottom plate extended parts 24, and the upper ends of the single-leg anchor bars 11 extend out of the upper surface of the bottom plate extended parts 24 so as to be welded with the left single-leg bars 18 and the right single-leg bars 19 in the self-stressed rigid beam 4. Bottom plate transverse connecting steel bars 10 are cast in the self-stressed bottom plate 1, and the bottom plate transverse connecting steel bars 10 are evenly arranged in the length direction of the self-stressed bottom plate 1. The ends of the bottom plate transverse connecting steel bars 10 extend out through the outer side of the thin ribbed plate 2, and the extended parts form an upward inclined steel bar extended part 27.

[0026] The top plate transverse connecting steel bars 9 are cast in the top plate 3, and the top plate transverse connecting steel bars 9 are evenly arranged in the length direction of the top plate 3 (i.e., the driving direction of the road). The two ends of the top plate transverse connecting steel bars 9 extend out of the outer side surface of the top plate 3, and the extended parts form downward inclined steel bar extensions 26. For two adjacent hollow slabs, the downward inclined steel bar extensions 26 of the top plate transverse connecting steel bars 9 in the top plate 3 are welded and cast in the self-stressed rigid beam 4. Correspondingly, the upward inclined steel bar extensions 27 of the two adjacent bottom plate transverse connecting steel bars 10 in the self-stressed bottom plate 1 are also welded together and cast in the self-stressed rigid beam 4.

[0027] The self-stressed rigid beam 4 shown is composed of micro-expansive concrete 22 and left single-leg reinforcement 18, right single-leg reinforcement 19, rigid beam longitudinal reinforcement 20, rigid beam stirrups 21, two adjacent welded downward inclined steel bar extensions 26, and two adjacent welded upward inclined steel bar extensions 27. The length direction of the rigid beam longitudinal reinforcement 20 is consistent with the length direction of the self-stressed rigid beam 4. The rigid beam stirrups 21 are rectangular. The rigid beam stirrups 21 are evenly arranged in the length direction of the self-stressed rigid beam 4. The rigid beam longitudinal reinforcement 20 is tied and connected with the rigid beam stirrups 21. The left single-leg reinforcement 18 and the right single-leg reinforcement 19 are both arranged vertically and tied with the rigid beam longitudinal reinforcement 20. The lower ends of the left single-leg reinforcement 18 and the right single-leg reinforcement 19 are welded to the upper ends of the single-leg reinforcement anchor bars 11.

[0028] It can be seen that the two welded lower oblique steel bar extensions 26, two upper oblique steel bar extensions 27, and the left single-limb tendon 18 and the right single-limb tendon 19 are all cast in the self-stressed rigid beam 4. The lower oblique steel bar extensions 26 and the upper oblique steel bar extensions 27 are equivalent to realizing the connection between the self-stressed rigid beam 4 and the hollow slab in the transverse direction, and the left single-limb tendon 18 and the right single-limb tendon 19 are equivalent to realizing the connection between the self-stressed rigid beam 4 and the hollow slab in the vertical direction. In this way, the rigid connection between the self-stressed rigid beam 4 and the hollow slabs on the left and right sides is realized, and the connection between two adjacent hollow slabs is also realized, so that the adjacent hollow slabs and the self-stressed rigid beam 4 therebetween are subjected to the same force and jointly bear the vehicle load above. Compared with the existing hinged joint connection method of the hollow slab, there will be no situation where a single hollow slab is subjected to force, thereby extending the service life of the hollow slab and the bridge structure formed by it.

[0029] The self-stressed base plate 1 shown is composed of high expansion concrete 8 and longitudinal self-stressed tendons 6, self-stressed tendon stirrups 7, base plate transverse connecting steel bars 10, single-limb tendon anchor bars 11 and expansion plates 5 cast in the high expansion concrete. The longitudinal self-stressed tendons 6 are evenly arranged in the self-stressed base plate 1, and their length direction is consistent with the length direction of the self-stressed base plate 1. The self-stressed tendon stirrups 7 are rectangular, and the self-stressed tendon stirrups 7 are evenly arranged in the length direction of the self-stressed base plate 1. The longitudinal self-stressed tendons 6 are tied and connected with the self-stressed tendon stirrups 7. Multiple expansion plates 5 are arranged at both ends of the self-stressed base plate 1, and the two ends of the longitudinal self-stressed tendons 6 are welded to the expansion plates 5. The lower end of the single-limb tendon anchor bar 11 is tied to the longitudinal self-stressed tendons 6, and the lower end of the shear reinforcement 12 in the thin rib plate 2 is also tied to the longitudinal self-stressed tendons 6.

[0030] In this way, after the high-expansion concrete 8 is poured and solidified, the expansion of the high-expansion concrete 8 will drive the expansion plates 5 on both sides to move slightly outward, and the expansion plates 5 that move slightly outward will pull the longitudinal self-stressing tendons 6 to stretch slightly. At the same time, the longitudinal self-stressing tendons 6 that have undergone elongation deformation will apply pressure in the longitudinal direction to the high-expansion concrete 8 through the expansion plates 5, so that the self-stressing bottom plate 1 has a longitudinal compressive stress. Since the hollow slab is in use, its lower side (i.e., the self-stressing plate 1) is in a tensile state and the upper side (i.e., the top plate 3) is in a compressive state, therefore, the self-stressing bottom plate 1 that has a longitudinal compressive stress itself can well bear the tensile force, ensuring that the hollow slab has sufficient bearing capacity.

[0031] At the same time, due to the use of high expansion concrete 8, when cracks appear at the bottom of the hollow slab, water is sprinkled, and the moisture reacts chemically with the expansion agent in the self-stress bottom slab 1 that has not yet reacted chemically, and the cracks at the bottom of the slab can be automatically healed, solving the national problem of difficult maintenance of cracks at the bottom of bridge slabs. Moreover, after solidification, the high expansion concrete 8 is dense and has few pores, making the longitudinal self-stress reinforcement 6, self-stress reinforcement stirrups 7 and bottom slab transverse connecting steel bars 10 inside it not easy to rust, further extending the service life of the hollow slab.

[0032] The thin ribbed plate 2 shown is cast above the self-stressed plate 1. The thin ribbed plate 2 is composed of ordinary concrete 14 and thin ribbed longitudinal reinforcement 13 and shear steel bars 12 cast therein. The length direction of the thin ribbed longitudinal reinforcement 13 is consistent with the length direction of the thin ribbed plate 2. The shear steel bars 12 are vertically arranged and evenly arranged in the length direction of the thin ribbed plate 2. The lower end of the shear steel bar 12 is tied and connected to the longitudinal self-stressed reinforcement 6 in the self-stressed bottom plate 1, and the upper end is tied to the top plate longitudinal reinforcement 16 in the top plate 3.

[0033] The top plate 3 shown is composed of ordinary concrete 14 and top plate longitudinal ribs 15, top plate transverse ribs 15 and top plate transverse connecting steel bars 9 cast therein. During construction, the high expansion concrete 8 forming the self-stressed bottom plate 1 is cast first, and then the ordinary concrete 14 forming the thin rib plate 2 and the top plate 3 is cast in sequence after curing 7. The length direction of the top plate longitudinal ribs 16 shown is consistent with the length direction of the top plate 3, the top plate transverse ribs 15 and the top plate transverse connecting steel bars 9 are evenly arranged in the length direction of the top plate 3, and the top plate transverse ribs 15 are tied and connected with the top plate longitudinal ribs 16.

[0034] During construction, two adjacent hollow slabs are spaced apart so that a slab bottom joint 23 is formed between the bottom slab extensions 24 of the two adjacent hollow slabs. For example, the width of the slab bottom joint 23 can be 2 cm, and micro-expanded fine stone concrete is poured in the slab bottom joint 23. The micro-expanded fine stone concrete is graded 40MPa-45MPa. The hollow slab ends 17 formed by concrete pouring are provided at both ends of the hollow cavity 25 of the hollow slab to ensure that the ends of the hollow slab have sufficient bearing capacity.

[0035] Specifically, the longitudinal reinforcement 20 of the self-stressed rigid beam 4 is provided with three rows of upper, middle and lower bars. Two adjacent lower inclined steel bar extensions 26 pass through the lower part of the upper row of the longitudinal reinforcement 20 of the rigid beam and are welded to each other. Two adjacent upper inclined steel bar extensions 27 pass through the upper part of the lower row of the longitudinal reinforcement 20 of the rigid beam and are welded to each other. In this way, the rigid connection between the self-stressed rigid beam 4 and the hollow slab is further ensured, that is, the rigid connection between the adjacent hollow slabs is ensured.

[0036] The longitudinal self-stressing tendons 6 in the self-stressing base plate 1 shown are arranged in two rows, upper and lower. The transverse connecting steel bars 10 of the base plate pass between the upper row of longitudinal self-stressing tendons 6 and the lower row of longitudinal self-stressing tendons 6. The lower ends of the single-leg anchor bars 11 are tied and connected to the longitudinal self-stressing tendons 6 at the ends of the lower row, and the lower ends of the shear steel bars 12 are also tied to the longitudinal self-stressing tendons 6 in the lower row.

[0037] In order to make the formed bridge self-stressed hollow slab structure have good shear resistance, the shear steel bars 12 are gradually denser from the middle to both ends in the length direction of the thin rib 2, and the left single branch bar 18 and the right single branch bar 19 are gradually denser from the middle to both ends in the length direction of the self-stressed rigid beam 4, that is, they are arranged in the form of "sparse in the middle and dense at both ends".

[0038] The construction method of the bridge self-stressed hollow slab structure of the present invention is achieved by the following steps: a). First, the expansion plate 5 and the longitudinal self-stressing reinforcement 6 are welded on the prefabricated bottom mold of the hollow slab, and then the self-stressing reinforcement stirrups 7, shear reinforcement 12, bottom plate transverse connecting reinforcement 10, single-leg reinforcement anchoring reinforcement 11 and thin ribbed longitudinal reinforcement 13 are tied; b). Next, support the outer formwork of the hollow slab, and then pour the high expansion concrete 8 to form the self-stressed bottom plate 1, and water cure for 7 days to form the self-stressed bottom plate; c). Then, support the inner formwork of the hollow slab and tie the longitudinal reinforcement 16 of the top slab and the transverse connecting reinforcement 9 of the top slab; d). Then, ordinary concrete is poured to form the thin rib plate 2 and the top plate 3 in sequence. After the outer and inner formworks of the hollow plate are removed, the entire hollow plate is sprinkled with water for curing for 7 days; e). Then, a hollow slab is installed on the bridge cap beam, and slightly expanded fine stone concrete is poured in the slab bottom joint 23 between the bottom slab extension 24 of two adjacent hollow slabs; then, the lower ends of the left single-leg reinforcement 18 and the right single-leg reinforcement 19 are welded to the upper ends of the single-leg reinforcement anchoring reinforcement 11, and the two top slab transverse connecting steel bars 9 and the two bottom slab transverse connecting steel bars 10 are welded, and then, the rigid beam longitudinal reinforcement 20 is tied to the rigid beam stirrup 21 to form a steel skeleton of the self-stressed rigid beam 4; f). Finally, pour micro-expansion concrete above the bottom plate extension 24 of the two adjacent hollow plates, sprinkle water and cure for 7 days, and finally form a bridge self-stressed hollow plate structure.

[0039] The dosage of the expansion agent in the micro-expansive concrete 22 is 5% to 8%, preferably 5%, 6%, 7%, and 8%.

[0040] The hollow plate has a length of 10m to 13m, preferably 10m or 13m, a width of 98cm to 123cm, preferably 98cm or 123cm, and a height of 60cm to 80cm, preferably 60cm, 70cm or 80cm. The self-stressed bottom plate 1 has a width of 98cm to 123cm, preferably 98cm or 123cm, a thickness of 12cm to 15cm, preferably 12cm or 15cm, and a length of 10m to 13m, preferably 10m or 13m.

[0041] The thickness of the thin rib plate 2 is 8cm~9cm, preferably 8cm, 9cm, the thickness of the top plate 3 is 10cm~12cm, preferably 10cm or 12cm; the width of the self-stressed rigid beam 4 is 26cm~30cm, preferably 26cm, 28cm or 30cm, and the thickness of the expansion plate 5 is 1.5cm~2.0cm, preferably 1.5cm or 2.0cm. The spacing between adjacent top plate transverse connecting steel bars 9 and adjacent bottom plate transverse connecting steel bars 10 is 15cm~25cm, preferably 15cm, 20cm or 25cm. The spacing between adjacent rigid beam stirrups 21 is 15cm~25cm, preferably 15cm, 20cm or 25cm.

[0042] The longitudinal self-stressing reinforcement 6 shown is made of HRB400 steel bars with a diameter of 16mm~25mm, preferably 16mm, 18mm, 22mm or 25mm; the bottom plate transverse connecting reinforcement 10 and the top plate transverse connecting reinforcement 9 are both made of HRB335 steel bars with a diameter of 16mm~22mm, preferably 16mm, 18mm, 20mm or 22mm; the single-limb reinforcement anchor bar 11, the shear reinforcement 12, the thin ribbed longitudinal reinforcement 13, and the top plate longitudinal reinforcement 16 are all made of HRB335 steel bars with a diameter of 12mm~14mm, preferably 12mm or 14mm; the self-stress value generated by the high expansion concrete 8 in the longitudinal direction of the self-stressing bottom plate 1 after solidification is 5MPa~7MPa, preferably 5MPa, 6MPa or 7MPa; the ordinary concrete 14 and the micro-expansion concrete 22 are marked with 40MPa~45MPa, preferably 40MPa or 45MPa.

Claims

1. A self-stressed hollow slab structure for a bridge, comprising a hollow slab and a self-stressed rigid beam (4) for connecting two adjacent hollow slabs, wherein both ends of the hollow slab are laid on a cap beam of the bridge, the hollow slab is composed of a self-stressed bottom slab (1), two thin ribs (2) and a top slab (3), the two sides of the top slab are connected to the self-stressed bottom slab via the two thin ribs, and a hollow cavity (25) is formed between the bottom slab, the two thin ribs and the top slab; the characteristics are: The two sides of the self-stressed bottom plate are bottom plate extensions (24) extending outward from the outer side of the thin rib plate, and the bottom plate extensions are pre-buried with vertical single-leg anchor bars (11) exposed on their upper surfaces; the self-stressed bottom plate (1) is evenly distributed with bottom plate transverse connecting steel bars (10) extending outward from the outer side of the thin rib plate, and the extended parts of the bottom plate transverse connecting steel bars form upward inclined steel bar extensions (27); the top plate is evenly distributed with top plate transverse connecting steel bars (9) extending outward from the outer side, and the extended parts of the top plate transverse connecting steel bars form downward inclined steel bar extensions (26); the self-stressed rigid beam is cast above the two adjacent bottom plate extensions; The self-stressed rigid beam is composed of micro-expansive concrete (22) and rigid beam longitudinal reinforcement (20) cast therein, rigid beam stirrups (21), left single-leg reinforcement (18), right single-leg reinforcement (19), two adjacent downward inclined reinforcement extensions (26) and two adjacent upward inclined reinforcement extensions (27). The stirrups of the rigid beam are rectangular and evenly distributed along the length direction of the self-stressed rigid beam. The stirrups of the rigid beam are tied to the rigid beam longitudinal reinforcement. The lower ends of the left single-leg reinforcement and the right single-leg reinforcement are welded to the single-leg reinforcement anchoring reinforcement, and the upper ends are tied to the rigid beam longitudinal reinforcement. The two adjacent downward inclined reinforcement extensions and the two adjacent upward inclined reinforcement extensions are welded.

2. The self-stressed hollow slab structure of a bridge according to claim 1, characterized in that: The self-stressed bottom plate (1) is composed of high expansion concrete (8), longitudinal self-stressed tendons (6), self-stressed tendon stirrups (7), bottom plate transverse connecting steel bars (10) and expansion plates (5), the self-stressed tendon stirrups are rectangular, the self-stressed tendon stirrups and the bottom plate transverse connecting steel bars are evenly arranged in the length direction of the self-stressed bottom plate, the self-stressed tendon stirrups are tied to the longitudinal self-stressed tendons, the expansion plates are arranged at both ends of the self-stressed bottom plate, and the two ends of the longitudinal self-stressed tendons are welded to the expansion plates.

3. The self-stressed hollow slab structure of the bridge according to claim 2 is characterized in that: The top plate (3) is composed of ordinary concrete (14) and top plate transverse reinforcements (15), top plate longitudinal reinforcements (16) and top plate transverse connecting reinforcements (9) cast therein, the top plate longitudinal reinforcements are evenly arranged in the width direction of the top plate, and the top plate transverse reinforcements and top plate transverse connecting reinforcements are evenly arranged in the length direction of the top plate.

4. The self-stressed hollow slab structure of the bridge according to claim 3 is characterized in that: The thin ribbed plate (2) is composed of ordinary concrete (14) and thin ribbed plate longitudinal reinforcement (13) and shear reinforcement (12) cast therein, the length direction of the thin ribbed plate longitudinal reinforcement is consistent with the length direction of the thin ribbed plate, and the shear reinforcement is gradually increased from the middle to the two ends in the length direction of the thin ribbed plate; the lower end of the shear reinforcement is tied to the longitudinal self-stressing reinforcement (6), the upper end of the shear reinforcement is tied to the top plate longitudinal reinforcement (16), and the thin ribbed plate longitudinal reinforcement is tied to the shear reinforcement.

5. The self-stressed hollow slab structure of the bridge according to claim 4 is characterized in that: The self-stressed rigid beam (4) is provided with upper, middle and lower rows of rigid beam longitudinal bars (20); two adjacent lower oblique steel bar extensions (26) are passed through the upper row of rigid beam longitudinal bars and then welded together; two adjacent upper oblique steel bar extensions (27) are passed through the lower row of rigid beam longitudinal bars and then welded together; the self-stressed bottom plate (1) is provided with upper and lower rows of longitudinal self-stressed bars (6); the lower ends of the single-leg anchor bars (11) are tied and connected to the lower row of longitudinal self-stressed bars; the lower ends of the shear steel bars (12) are tied and connected to the lower row of longitudinal self-stressed bars; the bottom plate transverse connecting steel bars (10) are located between the upper row of longitudinal self-stressed bars and the lower row of self-stressed bars; the left single-branch bars (18) and the right single-branch bars (19) are gradually denser from the middle to the two ends in the length direction of the self-stressed rigid beam; the rigid beam stirrups (21) are evenly distributed in the length direction of the self-stressed rigid beam.

6. The self-stressed hollow slab structure of a bridge according to claim 4 or 5, characterized in that: A slab bottom joint (23) is provided between the bottom slab extensions (24) of two adjacent hollow slabs. The width of the slab bottom joint is 2 cm. Micro-expanded fine stone concrete is poured in the slab bottom joint. The micro-expanded fine stone concrete has a grade of 40 MPa to 45 MPa. Hollow slab heads (17) formed by pouring concrete are provided at both ends of the hollow cavity (25) of the hollow slab.

7. The self-stressed hollow slab structure of a bridge according to claim 4 or 5, characterized in that: The hollow plate has a length of 10m to 13m, a width of 98cm to 123cm, and a height of 60cm to 80cm; the width of the self-stressed bottom plate (1) is 98cm to 123cm, the thickness is 12cm to 15cm, and the length is 10m to 13m; the thickness of the thin rib plate (2) is 8cm to 9cm, the thickness of the top plate (3) is 10cm to 12cm, the width of the self-stressed rigid beam (4) is 26cm to 30cm, and the thickness of the expansion plate (5) is 1.5cm to 2.0cm; The spacing between adjacent top plate transverse connecting steel bars (9) and adjacent bottom plate transverse connecting steel bars (10) is 15 cm to 25 cm, and the spacing between adjacent rigid beam stirrups (21) is 15 cm to 25 cm.

8. The self-stressed hollow slab structure of a bridge according to claim 4 or 5, characterized in that: The longitudinal self-stressing reinforcement (6) is made of HRB400 steel bars with a diameter of 16 mm to 25 mm, the bottom plate transverse connecting reinforcement (10) and the top plate transverse connecting reinforcement (9) are made of HRB335 steel bars with a diameter of 16 mm to 22 mm, and the single-leg reinforcement anchoring reinforcement (11), shear reinforcement (12), thin ribbed longitudinal reinforcement (13), and top plate longitudinal reinforcement (16) are made of HRB335 steel bars with a diameter of 12 mm to 14 mm; After solidification, the self-stress value generated by the high-expansion concrete (8) in the longitudinal direction of the self-stress base plate (1) is 5MPa~7MPa, while the values ​​of the ordinary concrete (14) and the micro-expansion concrete (22) are 40MPa~45MPa.

9. A construction method for the bridge self-stressed hollow slab structure according to claim 4 or 5, characterized in that: This is accomplished by following these steps: a). First, the expansion plate (5) and the longitudinal self-stressing reinforcement (6) are welded on the precast bottom form of the hollow slab, and then the self-stressing reinforcement stirrups (7), shear reinforcement (12), bottom slab transverse connecting reinforcement (10), single-leg reinforcement anchoring reinforcement (11) and thin ribbed longitudinal reinforcement (13) are tied; b). Then, the outer formwork of the hollow slab is supported, and then high expansion concrete (8) is poured to form a self-stressed bottom slab (1), and water-cured for 7 days; c). Then, support the inner formwork of the hollow slab and tie the top slab transverse reinforcement (15), top slab longitudinal reinforcement (16) and top slab transverse connecting reinforcement (9); d). Then, ordinary concrete is poured to form the thin rib plate (2) and the top plate (3) in sequence, and after the outer and inner formworks of the hollow plate are removed, the entire hollow plate is sprinkled with water for curing for 7 days; e). Then, a hollow slab is installed on the bridge cap beam, and slightly expanded fine stone concrete is poured in the slab bottom joint (23) between the bottom slab extensions (24) of two adjacent hollow slabs; then, the lower ends of the left single-leg reinforcement (18) and the right single-leg reinforcement (19) are welded to the upper ends of the single-leg reinforcement anchoring reinforcement (11), and the two top slab transverse connecting steel bars (9) and the two bottom slab transverse connecting steel bars (10) are welded together, and then, the rigid beam longitudinal reinforcement (20) and the rigid beam stirrups (21) are tied together to form a steel skeleton of the self-stressed rigid beam (4); f). Finally, pour micro-expansion concrete on the top of the bottom plate extension (24) of the two adjacent hollow plates, sprinkle water and cure for 7 days, and finally form a bridge self-stressed hollow plate structure.

10. The construction method of the bridge self-stressed hollow slab structure according to claim 9, characterized in that: The amount of the expansion agent in the micro-expansive concrete (22) is 5% to 8%.

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