CN112779852A - Hollow continuous beam bridge V-shaped stay segment and construction method adapting to soft soil foundation area - Google Patents
Hollow continuous beam bridge V-shaped stay segment and construction method adapting to soft soil foundation area Download PDFInfo
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- CN112779852A CN112779852A CN202110295484.7A CN202110295484A CN112779852A CN 112779852 A CN112779852 A CN 112779852A CN 202110295484 A CN202110295484 A CN 202110295484A CN 112779852 A CN112779852 A CN 112779852A
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D19/00—Structural or constructional details of bridges
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D19/00—Structural or constructional details of bridges
- E01D19/04—Bearings; Hinges
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D2/00—Bridges characterised by the cross-section of their bearing spanning structure
- E01D2/04—Bridges characterised by the cross-section of their bearing spanning structure of the box-girder type
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01D—CONSTRUCTION OF BRIDGES, ELEVATED ROADWAYS OR VIADUCTS; ASSEMBLY OF BRIDGES
- E01D21/00—Methods or apparatus specially adapted for erecting or assembling bridges
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Abstract
The invention discloses a V-shaped support section of a hollow continuous beam bridge and a construction method suitable for a soft soil foundation area, wherein the construction method comprises a lower chord beam, an upper chord beam and an upper and lower chord converging section; the lower chord beam comprises a root beam at the support and a V-shaped lower chord arranged symmetrically to the root beam at the support; two ends of the two V-shaped lower chords are connected with the first pouring sections of the beam at the converging section of the upper chord and the lower chord on the outer side; an upper chord beam is arranged between the second pouring sections of the two upper chord member and lower chord member converging section beams, and the upper chord member and the lower chord member are connected with the corresponding second pouring sections through the upper chord member; and a third batch pouring section is arranged at the position of each outer side upper chord member and lower chord member converging section beam corresponding to the outer sides of two ends of the corresponding upper chord member beam. During construction, the lower chord beam and the first batch of pouring sections are poured firstly, the upper chord beam and the second batch of pouring sections are poured, and the third batch of pouring sections are poured finally. The structure permeability and the tensile property of the top area of the root beam at the lower chord support are obviously improved, the landscape effect is improved, and the problem of stress concentration is solved; the construction period and cost are reduced.
Description
Technical Field
The invention relates to the technical field of bridge construction, in particular to a V-shaped stay section of an open-web continuous beam bridge and a construction method suitable for a soft soil foundation area.
Background
The hollow continuous beam bridge system has the advantages that the height of the root of the traditional continuous box beam support is increased, the web plate of the corresponding box beam is hollowed to form the separation of the upper chord and the lower chord of the hollow section, the dead weight is reduced, the hollow continuous beam bridge system is essentially different from the traditional box beam, and the root area forms a reasonable beam-arch combined stress mechanism.
The height of the pier body is reduced through the arrangement of the V-shaped support, the structural rigidity is increased, and meanwhile, the stress span of the box girder except the V-shaped support is reduced, so that the spanning capacity of the traditional continuous box girder bridge is expanded. And the inverted image of the arched arc line close to the arc at the bottom of the box girder moves with the wave in water, the structure is novel, the line shape is simple and smooth, and the aesthetic appearance of modern bridges is more fully embodied.
The traditional hollow continuous beam bridge generally performs local hollowing on a corresponding box girder web (the web of a box girder at the root of a support is reserved and is not hollowed, and a hollowed area forms two right-angled triangles which are symmetrically arranged) so as to solve the problem of stress concentration generated by the top surface of the root girder at the support of a lower chord member, but the whole landscape effect of the bridge is influenced due to the poor permeability of the structure under the bridge.
Meanwhile, the V-shaped support structure of the hollow continuous beam is a statically indeterminate structure, and is combined after the upper chord and the lower chord are separated to form a closed annular structure, and the structure and the stress of the closed annular structure are complex. The construction process is influenced by construction technology, concrete shrinkage, environment temperature and the like, the probability of cracks generated by a concrete structure is very high, the built bridge with the similar structure has cracks in different degrees, and the durability and the service life of the structure are greatly influenced. Therefore, the selection of a proper construction process is particularly critical to the final stress of the structure and the operability and the economy of construction.
The construction of the V-shaped support by a full-support method, a hanging basket and support method, a support and buckling rope method and the like is generally carried out, and some construction technical schemes of the established projects are listed below.
Wherein, the construction of the full-support method is to set up a support on land or in water as a support structure. The steel pipe pile upright is used as a foundation, the section steel is used as a main beam, a Bailey beam and a section steel distribution beam structure, and the upper part of the steel pipe pile upright is used as a height adjusting section by adopting a coil buckle scaffold. And after the construction of the V-shaped support lower chord, erecting a support on the lower chord to construct an upper chord, and tensioning permanent prestress after the V-shaped support closure is completed.
The construction of the full-support method adopts the full-support method, the stress of the whole structure is clear, and the control of each construction stage is facilitated. The construction speed is fast, and the construction period is short. The inelastic deformation and the foundation settlement of the bracket can be eliminated through prepressing, and the elastic deformation of the bracket is obtained.
The whole support method foundation needs to bear all loads of the lower chord and the upper chord, so the support engineering quantity is large. The height of the support is limited, and the support is not suitable for areas such as deep valleys and deep rivers.
The cradle and support construction method is characterized in that a pier-side support or a tripod construction lower chord 0# section is erected, a cradle is installed to symmetrically suspend and cast a lower chord section in sequence, the internal force and the line shape of the lower chord are adjusted through buckling rope opposite pulling in the construction process, a support construction upper chord is erected on the lower chord, and finally V-shaped support closure is completed by a cradle construction closure section.
The upper chord box girder and the lower chord inclined leg are constructed asynchronously, namely, the lower chord inclined leg is constructed firstly, then the upper chord box girder is constructed, and the lower chord inclined leg is ahead of the upper chord box girder in three construction sections. The lower chord inclined leg adopts an inclined hanging basket to cast in place, the upper hanging box girder adopts a steel pipe support to cast in place, and the upper chord and the lower chord are converted into the horizontal hanging basket construction residual sections after meeting.
The construction of the cradle and support method adopts the cradle suspension casting lower chord, firstly a 0# block triangular support needs to be erected, after the 0# block is cast in place, the cradle is installed and pre-pressed, then the lower chord is constructed section by section, and the total construction period is longer.
During construction, the lower chord line shape and the internal force are ensured by tensioning the buckling rope, and the control difficulty is high when the rope force is adjusted for many times to reach the final construction stage.
In construction, only the starting segment needs bracket investment, and the bracket investment amount is small. Is not limited by terrain, and is suitable for construction of various complex terrains. All the operations are suspended operations, so that the safety risk is high.
The construction of the bracket and the buckle cable method is to erect the bracket in a bearing platform and water to be used as a supporting structure. The steel pipe pile is used as a foundation, the flange steel pipe is used as a stand column, the section steel main beam and the section steel distribution beam are of a structure, and the flange at the upper part adopts a coil buckle scaffold as a height adjusting section. After the construction of the V-shaped support lower chord, tensioning the temporary prestress for the first time, arranging a support on the lower chord for constructing an upper chord (pouring for 2 times and reserving a post-pouring belt), and tensioning the temporary prestress for the second time after the first pouring of the upper chord is finished. And pouring a post-cast strip and an upper chord top plate to complete the tension permanent prestress after the V-shaped stay closure.
The construction of the bracket and buckle cable method adopts the construction of the bracket and buckle cable method, the stress of the whole structure is definite, and the control in the construction stage is facilitated. The construction speed is fast, and the period of the practics is short. The inelastic deformation and the foundation settlement of the bracket can be eliminated through prepressing, and the elastic deformation of the bracket is obtained.
Because the temporary buckle cable support does not bear all loads of the lower chord and the upper chord, the engineering quantity of the support is small.
The height of the support is limited, and the support is not suitable for areas such as deep valleys and deep rivers.
When the main span of the bridge is less than 100m and the requirement on the navigation clearance under the bridge during construction is not high, the construction method is generally preferred to adopt a full-support construction method because the construction measures and the construction cost of the construction process of the cradle plus support method or the support plus buckle cable method are high, the construction period is long, and the feasibility of the scheme is low.
When the V-shaped support structure is located in a soft soil foundation area, if a full-support construction method is adopted, because a lower chord needs to be constructed firstly, and then a support is erected on the lower chord for constructing an upper chord, when concrete at the junction section of the upper chord and the lower chord is poured at the later stage, the support structure under the lower chord and the template at the junction section of the upper chord and the lower chord is subjected to elastic-plastic deformation and settlement to cause adverse effects on a root beam at the support position of the lower chord poured at the earlier stage, and the lower chord is generally provided with a temporary pull rod during construction, so that the construction process is complex, and the measure cost is high.
However, if the construction is carried out by adopting the hanging basket and support method or the support and buckle cable method, the total construction period is longer, the construction process is complex, and the construction cost and the construction temporary measure cost are higher.
Therefore, how to overcome the defects of poor landscape effect and complex structure and stress of the V-shaped support structure in the prior art, the final stress performance and durability of the structure are improved, the construction operation process is simplified to increase the economic benefit, and the technical problem which needs to be solved by technical personnel in the field is provided.
Disclosure of Invention
In view of the defects in the prior art, the invention provides the V-shaped support section of the hollow continuous beam bridge and the construction method suitable for the soft soil foundation area, and the purpose of improving the overall landscape effect of the bridge by improving the permeability of the structure under the bridge deck is achieved; the problem of structural stress concentration is solved by improving the tensile property of the top area of the root beam at the lower chord support; by horizontally layering and vertically casting the V-shaped support section hollow structure and tensioning permanent prestressed steel bundles in the structure in batches, the construction period, the cost and the complexity are minimized on the premise of ensuring the safety and the durability of the structure, so that the economic benefit and the structural durability are improved.
In order to achieve the purpose, the invention discloses a V-shaped stay section of a hollow continuous beam bridge, which comprises a lower chord beam, an upper chord beam and an outer upper chord and lower chord converging section beam.
The upper chord beam and the lower chord beam are closed to form an inverted trapezoidal hollowed annular structure, and a vertical connecting tie rod is not arranged between the upper chord beam and the lower chord beam;
the lower chord beam comprises a support root beam made of common concrete and a top surface layer of ultra-high performance concrete surface layer, a combined cross section structural form is formed by adopting a combined structural technology of integral through arrangement of common steel bars and upper and lower superposition pouring of concrete, and two V-shaped lower chords which are respectively connected with two sides of the support root beam and are upwards tilted to form a V shape;
a plurality of lower chord prestressed steel bundles are arranged in the root beam at the support and the V-shaped lower chord;
two ends of each lower chord prestressed steel beam extend and are anchored at the inner tensioning notch of the V-shaped lower chord close to the lower end of the corresponding side;
two ends of the two V-shaped lower chords are connected with a first pouring section of the outer upper and lower chord converging section beam close to the lower end, and the outer upper and lower chord converging sections at the two ends of the two V-shaped lower chords are symmetrically arranged;
the upper chord beam is arranged between the two symmetrical upper chord member and lower chord member converging section beams;
two ends of the upper chord member beam are respectively and fixedly connected with a second batch of pouring sections at the middle part and the top part of the beam of the outer side upper chord member and lower chord member converging section after synchronous pouring;
a third pouring section is arranged at the position, corresponding to the outer side of the second pouring section at the two ends of the upper chord beam, of each outer side upper chord member and lower chord member converging section beam;
a first batch of tensioned upper chord prestressed steel bundles and a second batch of tensioned upper chord prestressed steel bundles are arranged in the upper chord beam;
two ends of each first group of tensioned upper chord prestressed steel bundles extend and are anchored in the corresponding second group of pouring sections respectively;
and two ends of each second batch of tensioned upper chord prestressed steel bundles extend and are anchored in the corresponding third batch of pouring sections respectively.
Preferably, the upper chord beam and the second batch of pouring sections are in an Jiong shape, both ends of the upper chord beam are provided with downwards extending prestressed steel bundle tensioning and anchoring tooth block structures, and the upper chord beam and the second batch of pouring sections are synchronously poured and consolidated with the corresponding prestressed steel bundle tensioning and anchoring tooth block structures and the corresponding second batch of pouring sections;
the first pouring section of each outer upper chord member and lower chord member converging section beam is provided with an upper chord member and lower chord member semicircular transition section which extends upwards and is matched with the corresponding prestressed steel bundle tensioning and anchoring tooth block structure respectively at the position corresponding to the inner side of the prestressed steel bundle tensioning and anchoring tooth block structure;
the prestressed steel beam tension anchoring tooth block structures at two ends of each upper chord member beam are clamped with the upper chord member semicircular transition section and the lower chord member semicircular transition section which are matched on the corresponding pair of outer upper chord member and outer lower chord member converging section beams;
and each upper chord rod semicircular transition section and each lower chord rod semicircular transition section are integrally cast with the corresponding first batch of casting sections and the corresponding second batch of casting sections.
More preferably, a first group of tensioned upper chord prestressed steel bundles and a second group of tensioned upper chord prestressed steel bundles are arranged in the upper chord beam and the prestressed steel bundle tensioning and anchoring tooth block structures at the two ends of the upper chord beam.
Preferably, the outer upper chord member and the outer lower chord member converging section beam are of a box girder structure.
Preferably, the lower chord beam is provided with a support, a pier body/upright post and a pier bearing platform in sequence below the root beam at the support.
The invention also provides a construction method for adapting the V-shaped stay segment of the hollow continuous beam bridge to a soft soil foundation area, which comprises the following steps:
and 10, tensioning the upper chord and the second batch of upper chord prestress steel bundles in the outer side upper chord and lower chord converging section beam.
Preferably, in the step 2, when the first batch of casting sections are cast, the bottom plate concrete of the beam of the outer side upper chord member and lower chord member converging section is cast.
The invention has the beneficial effects that:
1. according to the invention, the webs corresponding to the box girder support seat are synchronously hollowed, the vertical connecting tie bar between the upper chord and the lower chord at the support seat in the prior art is eliminated, and the two hollowed right-angled triangles are combined to form an inverted trapezoidal hollowed annular structure, so that the permeability of the lower structure of the bridge deck is obviously improved, and the overall landscape effect of the bridge is optimized.
2. According to the invention, by adopting a combined structure technology of integral through arrangement of common steel bars and upper and lower superposition pouring of concrete, the common concrete of the root beam at the lower chord support and a layer of ultra high performance concrete (UHPC for short) surface layer with the thickness of 10cm on the top surface are combined to form a combined cross-section structure form, and the prestressed steel beam is arranged in the combined cross-section structure form, so that the tensile property of the top area of the root beam at the lower chord support is improved, and the problem of structural stress concentration is solved.
3. The invention adopts the technology of horizontal layering and longitudinal segmental casting forming of the hollow structure of the V-stay section, and tensions permanent prestressed steel beams in the upper chord beam and the lower chord beam in batches according to the structural stress requirements in each construction process and also serves as temporary pull rods during construction, so that the adverse effects on the root beam at the cast lower chord support in the early stages, such as elastic-plastic deformation, foundation settlement and the like of the template support structure of the lower chord beam and the upper chord convergent section beam and the lower chord section beam caused by weak foundation reinforcement below the lower chord beam and the upper chord convergent section beam and the lower chord section beam in the later casting of the second casting section and the third casting section are reduced on the premise of not additionally increasing the temporary pull rods during construction, and the construction period, the cost and the complexity are minimized on the premise of ensuring the safety and the durability of the structure.
The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.
Drawings
Fig. 1 is a schematic diagram showing a state of completing concrete pouring of a first pouring section of a lower chord beam, a UHPC layer with the thickness of 10cm on the top surface and an outer upper chord member and lower chord member converging section beam in one embodiment of the invention.
Fig. 2 is a schematic view showing a state that concrete pouring of the second pouring section of the upper chord beam and the outer upper chord member and outer lower chord member converging section beam is completed in one embodiment of the invention.
Fig. 3 is a schematic view illustrating a state of completing concrete pouring of a third pouring section of the outer side upper chord member and lower chord member converging section beam according to an embodiment of the invention.
Detailed Description
Examples
As shown in FIG. 3, the V-shaped strut section of the hollow continuous beam bridge comprises a lower chord beam 1, an upper chord beam 2 and an outer upper chord and lower chord confluence section beam 3.
The upper chord beam 2 and the lower chord beam 1 are closed to form an inverted trapezoidal hollowed annular structure, and a vertical connecting tie rod is not arranged between the upper chord beam 2 and the lower chord beam 1;
the lower chord beam 1 comprises a support root beam 11 made of common concrete and a top surface layer 14 made of ultra-high performance concrete, a combined cross section structural form is formed by adopting a combined structural technology of integral through arrangement of common steel bars and upper and lower superposition pouring of concrete, and two V-shaped lower chords 12 which are respectively connected with two sides of the support root beam 11 and are upwards tilted to form a V shape;
a plurality of lower chord prestressed steel bundles 13 are arranged in the root beam 11 at the support and the V-shaped lower chord 12;
two ends of each lower chord prestress steel beam 13 extend and are anchored at the inner tensioning notch of the V-shaped lower chord 12 close to the lower end of the corresponding side;
two ends of each of the two V-shaped lower chords 12 are connected with a first pouring section 31, close to the lower end, of the outer upper chord member and lower chord member converging section beam 3, and the outer upper chord member and lower chord member converging sections 3 at the two ends of each of the two V-shaped lower chords 12 are symmetrically arranged;
an upper chord beam 2 is arranged between the two symmetrical upper chord member and lower chord member converging section beams 3;
two ends of the upper chord member beam 2 are respectively and fixedly connected with the second pouring sections 32 at the middle part and the top part of the corresponding outer upper chord member and lower chord member converging section beam 3 after synchronous pouring;
a third pouring section 33 is arranged at the position, corresponding to the outer side of the second pouring section 32, of the two ends of the corresponding upper chord beam 2, of each outer upper chord member and lower chord member converging section beam 3;
a first batch of tensioned upper chord pre-stress steel bundles 23 and a second batch of tensioned upper chord pre-stress steel bundles 21 are arranged in the upper chord beam 2;
two ends of each first tensioned upper chord prestressed steel bundle 23 respectively extend and are anchored in the corresponding second pouring section 32;
two ends of each second group of tensioned upper chord prestressed steel bundles 21 respectively extend and are anchored in the corresponding third group of pouring sections 33.
The principle of the invention is as follows:
synchronously hollowing the web plate at the position corresponding to the box girder support, canceling a vertical connecting tie rod between the upper chord girder 2 and the lower chord girder 1 in the prior art, combining two hollowed right-angled triangles to form an inverted trapezoid hollowed annular structure, obviously improving the permeability of the lower structure of the bridge deck, and optimizing the overall landscape effect of the bridge;
the lower chord beam 1 comprises a support root beam 11 made of common concrete and a top surface layer 14 made of ultra-high performance concrete, namely UHPC material, a combined structural form is formed by adopting a combined structural technology of integral through arrangement of common steel bars and upper and lower superposition pouring of concrete, and a lower chord prestressed steel beam 13 is arranged in the lower chord beam 1 to improve the tensile property of the concrete at the top area of the support root beam of the lower chord beam 1 and solve the problem of structural stress concentration;
pouring the beam 3 at the converging section of the upper chord member and the lower chord member at the outer side in three batches: firstly, synchronously pouring the first batch of pouring sections 31, common concrete and ultrahigh-performance concrete of the lower chord beam 1, and when the strength and the elastic modulus of the concrete reach the design strength, tensioning part of the lower chord prestress steel beams 13 to reduce the adverse effects on the root beam at the support of the lower chord beam 1 poured in the early stage caused by elastic-plastic deformation, foundation settlement and the like of the supporting structure 8 due to the equal weight of the upper chord template support 9, the upper chord beam 2 and the second batch of pouring sections 32;
the second batch of pouring sections 32 and the concrete of the upper chord beam 2 are poured synchronously, the second batch of pouring sections and the first batch of pouring sections 31 and the lower chord beam 1 are combined to form an inverted trapezoid hollowed closed ring structure, when the concrete strength and the elastic modulus reach the design strength, the residual tensioned lower chord pre-stress steel bundles 13 and the corresponding first batch of tensioned upper chord pre-stress steel bundles 23 in the upper chord beam are used as temporary pull rods during construction, and therefore adverse effects on the root beam at the support of the lower chord beam 1, such as elastic-plastic deformation and foundation settlement of the supporting structure 8 caused by the weight of the concrete of the third batch of pouring sections 33, are reduced.
According to the invention, the vertical connecting tie bars between the upper chord member and the lower chord member in the prior art are cancelled, and the technology of combining the sections of the ultra-high performance concrete at the root part beam of the support is adopted, so that the problem of poor overall landscape effect of the bridge caused by the fact that the vertical tie bars are arranged between the upper chord member and the lower chord member in order to avoid structural stress concentration in the prior art is solved; the V-shaped support section hollow structure adopts a horizontal layering and longitudinal segmentation pouring forming technology, and permanent prestressed steel bundles in a batch tensioning structure are also used as temporary pull rods during construction, so that the construction period and cost are reduced on the premise of ensuring the safety and durability of the structure;
firstly, through the vertical tie rod of connecting between the upper and lower chord of cancellation support department among the prior art in order to increase the structure fretwork area in the cyclic annular enclosure space of upper and lower chord, showing the penetrating rate that improves the bridge floor lower structure, realize the whole view effect optimization of bridge, specifically as follows:
1. the integral cross section of the root beam 11 at the support is common concrete 11 and ultrahigh-performance concrete 14, and a combined structural form of integral through arrangement of common steel bars and concrete up-down superposition pouring is adopted to form a combined cross section structural form;
2. in order to increase the effective pre-stress of the prestressed steel bundles, the pipeline arrangement position of the prestressed steel bundles 13 at the support is as close as possible to the top edge of the combined section of the support 11 and the support 14;
3. because the thickness of the ultra-high performance concrete 14 is only 10cm, the structural requirement of the prestressed steel beam 13 pipeline arrangement cannot be met;
4. to facilitate the joining of the pre-stressed steel strand pipes to the concrete, the pre-stressed steel strands 13 are only arranged in the ordinary concrete 11 and as close to 14 as possible;
secondly, by adopting a combined structure technology of integral through arrangement of common steel bars and upper-lower superposition pouring of concrete, an ultrahigh-performance concrete surface layer 14 is combined and arranged on the top surface of the root beam at the support of the lower chord beam 1, namely a combined cross-sectional structure form with extremely high tensile strength in the top area is formed by combining an UHPC material and the common concrete, and meanwhile, a lower chord prestressed steel beam 13 is arranged, so that the effective pre-stress of the top surface of the root beam 11 at the support of the lower chord beam 1 and the ultrahigh-performance concrete surface layer 14 is further increased to strengthen the tensile performance of the concrete, and the problem of structural stress concentration is solved;
thirdly, the upper chord beam 2 and a first temporary pull rod used for tensioning the upper chord prestressed steel bundle 23 during construction are fixed with a second pouring section 32 of the two outer upper and lower chord converging section beams 3 to form a closed annular structure, so that the adverse effect of the weight of concrete of the third pouring section transmitted to the root beam at the support of the lower chord beam 1 is reduced;
and finally, a third pouring section 33 is arranged at the outer side of a second pouring section at the two ends of the upper chord beam 2 and at the upper end of a first pouring section of the beam 3 at the upper chord and the lower chord converging section at the outer side, and the connection between the third pouring section 33 and the upper chord beam 2 is strengthened through a second tensioning upper chord prestress steel beam 21 arranged in the upper chord beam 2, so that the adverse effect that the weight of concrete of the third pouring section 33 is transmitted to root beams at the support positions of the upper chord beam 2 and the lower chord beam 1 is reduced.
In some embodiments, the upper chord beam 2 and the second pouring section are in the shape of Jiong, both ends of the upper chord beam are provided with the prestressed steel-bundle tensioning anchoring tooth block structures 22 extending downwards, and the upper chord beam and the second pouring section are synchronously poured and solidified with the corresponding prestressed steel-bundle tensioning anchoring tooth block structures 22 and the corresponding second pouring section 32;
the first pouring section 31 of each outer upper chord member and lower chord member converging section beam 3 is provided with upper chord member and lower chord member semicircular transition sections 34 which extend upwards and are respectively matched with the corresponding prestressed steel bundle tensioning anchoring tooth block structures 22 corresponding to the positions of the inner sides of the corresponding prestressed steel bundle tensioning anchoring tooth block structures 22;
the prestressed steel beam tension anchoring tooth block structures 22 at two ends of each upper chord member beam 2 are clamped with the matched upper and lower chord member semicircular transition sections 34 on the corresponding pair of outer upper and lower chord member converging section beams 3;
each upper and lower chord semi-circular transition section 34 is integrally cast with a respective first plurality of casting sections 31 and a respective second plurality of casting sections 32.
In some embodiments, the first and second tensioned upper chord pre-stressing tendons 23 and 21 are provided in the upper chord 2 and the pre-stressing tendon tensioned anchoring tooth block structures 22 at both ends thereof.
In certain embodiments, the outboard upper and lower chord convergent section beams 3 are box beam structures.
In some embodiments, the lower chord beam 1 is provided with a support 4, a pier body/upright post 5 and a pier bearing platform 6 in sequence below the root beam 11 at the support.
As shown in fig. 1 to 3, the invention also provides a construction method for adapting the V-stay segment of the hollow continuous beam bridge to a soft soil foundation area, which comprises the following steps:
and 10, tensioning the upper chord 2 and a second batch of upper chord prestress steel bundles 21 in the corresponding outer upper chord and lower chord converging section beam 3.
In some embodiments, in step 2, casting the first plurality of cast sections 31 includes casting the floor concrete of the outer upper and lower chord confluence section beams 3.
In practical application, the web plates corresponding to the box girder support are synchronously hollowed, the vertical connecting tie bar between the upper chord and the lower chord of the support in the prior art is eliminated, the two hollowed right-angled triangles are combined to form an inverted trapezoidal hollowed annular structure, the permeability of the bridge floor lower structure is obviously improved, and the overall landscape effect of the bridge is optimized.
According to the invention, by adopting a combined structure technology of integral through arrangement of common steel bars and upper and lower superposition pouring of concrete, the common concrete at the lower chord beam support is combined with a surface layer of Ultra High Performance Concrete (UHPC) with a thickness of 10cm, which is arranged on the top surface of the common concrete, to form a combined cross-section structure form, and the prestressed steel bundles are arranged inside the combined cross-section structure form, so that the tensile property of the concrete at the top area of the root beam at the lower chord support is improved, and the problem of structural stress concentration is solved. The V-shaped stay segment hollow structure adopts the horizontal layering and longitudinal segmentation casting forming technology, and the permanent prestressed steel beams in the tension structure in batches are also used as temporary pull rods during construction, so that the construction period, the cost and the complexity are minimized on the premise of ensuring the safety and the durability of the structure, namely:
firstly, a lower chord beam 1 and a first batch of pouring section 31 of a beam of an upper chord and a lower chord confluence section are poured by a support, and when the strength and the elastic modulus of the concrete meet the design requirements, a part of a lower chord prestress steel beam 13 is tensioned;
then, erecting a support on the lower chord beam 1, pouring concrete of an upper chord beam 2 and a second pouring section 32 of the upper chord converging section beam and the lower chord converging section beam, closing and connecting the upper chord beam and the lower chord beam 1 into a whole, and tensioning the rest of lower chord prestressed steel bundles 13 and the first batch of upper chord prestressed steel bundles 23;
and finally, pouring 33 concrete of the third pouring section of the beam of the outer side upper chord member and outer side lower chord member converging section.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.
Claims (7)
1. The V-shaped stay section of the hollow continuous beam bridge is characterized by comprising a lower chord beam (1), an upper chord beam (2) and an outer upper chord and lower chord converging section beam (3), wherein the upper chord beam (2) and the lower chord beam (1) are closed to form an inverted trapezoidal hollowed annular structure, and a vertical connecting tie rod is not arranged between the upper chord beam (2) and the lower chord beam (1);
the lower chord beam (1) comprises a support root beam (11) made of common concrete and a top surface layer (14) made of ultra-high performance concrete, a combined structural form formed by the combination of integral through arrangement of common steel bars and the upper and lower superposition pouring of the concrete, and two V-shaped lower chords (12) which are respectively connected with two sides of the support root beam (11) and are upwards tilted to form a V shape;
a plurality of lower chord prestress steel beams (13) are arranged in the root beam (11) at the support and the V-shaped lower chord (12);
two ends of each lower chord prestress steel beam (13) extend and are anchored at an inner tension notch, close to the lower end, of the V-shaped lower chord (12) on the corresponding side;
two ends of the two V-shaped lower chords (12) are connected with a first pouring section (31) of the outer side upper chord member and lower chord member converging section beam (3) close to the lower end, and the outer side upper chord member and lower chord member converging sections (3) at the two ends of the two V-shaped lower chord members (12) are symmetrically arranged;
the upper chord beam (2) is arranged between the two symmetrical upper chord member and lower chord member converging section beams (3);
two ends of the upper chord member beam (2) are respectively and fixedly connected with a second pouring section (32) at the middle part and the top part of the outer side upper chord member and lower chord member converging section beam (3) after synchronous pouring;
a third pouring section (33) is arranged at the position, corresponding to the outer side of the second pouring section (32) at the two ends of the upper chord beam (2), of each outer side upper chord member and lower chord member converging section beam (3);
a first batch of tensioned upper chord prestressed steel bundles (23) and a second batch of tensioned upper chord prestressed steel bundles (21) are arranged in the upper chord beam (2);
two ends of each first tensioned upper chord prestressed steel bundle (23) respectively extend and are anchored in the corresponding second pouring section (32);
and two ends of each second group of tensioned upper chord prestressed steel bundles (21) respectively extend and are anchored in the corresponding third group of pouring sections (33).
2. The V-stay section of a hollow continuous girder bridge according to claim 1, wherein the upper chord girder (2) and the second pouring section are in the shape of Jiong, and both ends of the upper chord girder and the second pouring section are provided with prestressed tendon tensioning and anchoring tooth block structures (22) extending downwards, and are poured and fixed synchronously with the corresponding prestressed tendon tensioning and anchoring tooth block structures (22) and the corresponding second pouring section (32);
the first pouring section (31) of each outer upper chord member and lower chord member converging section beam (3) is provided with an upper chord member and lower chord member semicircular transition section (34) which extends upwards and is matched with the corresponding prestressed steel bundle tensioning and anchoring tooth block structure (22) at a position corresponding to the inner side of the corresponding prestressed steel bundle tensioning and anchoring tooth block structure (22);
the prestressed steel beam tensioning and anchoring tooth block structures (22) at the two ends of each upper chord beam (2) are clamped with the upper and lower chord semicircular transition sections (34) matched on the corresponding pair of outer upper and lower chord converging section beams (3);
each upper chord semicircular transition section (34) and each lower chord semicircular transition section (34) are integrally cast with the corresponding first batch of casting sections (31) and the corresponding second batch of casting sections (32).
3. The V-stay segment of a hollow continuous beam bridge according to claim 2, characterized in that the upper chord beam (2) and the pre-stressing tendon tensioning and anchoring tooth block structures (22) at both ends thereof are provided with a first set of tensioned upper chord pre-stressing tendons (23) and a second set of tensioned upper chord pre-stressing tendons (21).
4. The V-stay section of a hollow continuous girder bridge according to claim 1, wherein the outer upper and lower chord confluence section girders (3) are of box girder construction.
5. The V-stay section of the hollow continuous girder bridge according to claim 1, wherein a support (4), a pier body/column (5) and a pier abutment (6) are sequentially arranged below the root beam (11) at the support of the lower chord beam (1).
6. The construction method of adapting the V-stay segment of the hollow continuous beam bridge to the soft soil foundation area according to claim 1, comprising the following steps:
step 1, installing a temporary locking tension-compression column (7), and erecting a lower chord, an upper chord and a lower chord converging section template support (8);
step 2, pouring root beams (11) and top surface ultrahigh-performance concrete (14) of the lower chord beams (1) at the support positions, which are made of common concrete, and pouring the first batch of pouring sections (31) at the positions, corresponding to the two ends of the upper chord beam (2), of the upper ends of the two V-shaped lower chords (12);
step 3, tensioning the lower chord pre-stress steel bundle (13) of the lower chord beam (1);
step 4, erecting a template bracket (9) of the upper chord beam (2);
step 5, pouring the second pouring section (32) of the upper chord beam (2) and the outer side upper and lower chord converging section beam (3);
step 6, tensioning the residual lower chord prestress steel bundles (13) in the lower chord beam (1);
step 7, tensioning the upper chord beam (2) and tensioning the first batch of upper chord prestress steel bundles (23) in the anchoring gear block structure (22) by prestress steel bundles at two ends of the upper chord beam;
step 8, dismantling the template bracket (9) of the upper chord beam (2);
9, pouring a third pouring section (33) of the outer side upper chord member and lower chord member converging section beam (3);
and 10, tensioning the upper chord (2) and the second batch of upper chord pre-stress steel bundles (21) in the outer side upper chord and lower chord converging section beam (3).
7. The construction method for adapting the V-stay section of the open-web continuous girder bridge to the soft soil foundation area according to claim 1, wherein in the step 2, the first pouring section (31) is poured, and the bottom plate concrete of the outer upper and lower chord member junction section girder (3) is poured.
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