CN115679794B - Large-cantilever ultra-wide UHPC box girder unit, large-cantilever ultra-wide UHPC box girder bridge and construction method thereof - Google Patents

Abstract

The invention discloses a large cantilever ultra-wide UHPC box girder unit which comprises an UHPC box girder body, wherein UHPC flanges extending outwards are arranged on two sides of a transverse bridge on the upper surface of the UHPC box girder body, a plurality of UHPC outriggers arranged at intervals are arranged between the side surface of the UHPC box girder body and the bottom surface of each UHPC flange, a plurality of UHPC longitudinal ribs arranged at intervals are arranged below each UHPC flange, the UHPC outriggers are arranged along the transverse bridge direction, and the UHPC longitudinal ribs are arranged along the longitudinal bridge direction. The invention also provides a large cantilever ultra-wide UHPC box girder bridge and a construction method. The box girder bridge constructed by the large cantilever ultra-wide UHPC box girder unit can greatly improve the width of the bridge deck and the rigidity of the flange plate of the box girder under the condition that the transverse distance of the support is limited, can effectively avoid the cracking of the bridge deck and is convenient for assembly construction.

Description

Large-cantilever ultra-wide UHPC box girder unit, large-cantilever ultra-wide UHPC box girder bridge and construction method thereof

Technical Field

The invention belongs to the field of bridges, and particularly relates to a UHPC box girder unit, a UHPC box girder bridge and a construction method thereof.

Background

With the construction of the majored bridge and the development of urban traffic, more and more bridges need to be built in the sea and the cities, and with the increase of traffic flow and the improvement of road grade, part of newly built bridges require to build six bidirectional lanes or even eight bidirectional lanes, so that the width of the bridge reaches 35m or more. However, for the traditional wide box girder bridge, because the width of the bridge is greatly increased, the position of a bridge pier is limited by objective conditions (urban land shortage or severe offshore geological conditions and the like), the transverse distance of a bridge support is smaller, so that the cantilever arm of a box girder flange plate is longer, the transverse effect of the box girder structure of the bridge in the service process is obvious, obvious transverse shear deformation occurs, the vertical deformation of the end part of the transverse cantilever arm of the box girder is larger, the local rigidity is insufficient, and the bridge deck is easy to crack.

In order to solve the above technical problems, the prior art adopts a steel box girder structure and a combined box girder structure (steel-concrete combined girder), but the bridge structure not only increases the initial construction cost and the construction process (more details of welding lines) due to the adoption of steel, but also greatly increases the operation and maintenance cost due to the problems of steel fatigue and corrosion. In addition, the general steel box girder structure comprises a thick and heavy common concrete layer, so that on one hand, the self weight of the structure and the construction process are increased, and the assembly construction is not facilitated; on the other hand, the deck slab concrete will inevitably crack due to the repeated action of wheel loads and the lateral effect of the ultra-wide box girder. Therefore, the problem of cracking of the bridge deck of the ultra-wide box girder cannot be perfectly solved in the prior art.

Disclosure of Invention

The invention aims to solve the technical problems of overcoming the defects and shortcomings in the background technology and providing a large-cantilever ultra-wide UHPC box girder unit, a large-cantilever ultra-wide UHPC box girder bridge and a construction method thereof. In order to solve the technical problems, the technical scheme provided by the invention is as follows:

the utility model provides a big cantilever super wide UHPC case roof beam unit, includes UHPC case roof beam body, the cross bridge both sides of UHPC case roof beam body upper surface are equipped with the UHPC flange of outside extension, be equipped with multichannel interval arrangement's UHPC outrigger between the side of UHPC case roof beam body and the bottom surface on UHPC flange, UHPC flange below has arranged the UHPC of multichannel interval arrangement and has indulged the rib, the UHPC outrigger sets up along the cross bridge direction, UHPC indulges the rib and sets up along the longitudinal bridge direction.

In the above large-cantilever ultra-wide UHPC box girder unit, preferably, the UHPC box girder body includes a UHPC top plate, a UHPC bottom plate, a UHPC cross-slab, and a UHPC web arranged along a longitudinal bridge direction, the UHPC web is arranged between the UHPC top plate and the UHPC bottom plate and forms a box-type structure, the UHPC cross-slab includes at least one of a UHPC top plate stiffener, a UHPC web stiffener, and a UHPC bottom plate stiffener, the UHPC top plate stiffener is vertically arranged at the bottom of the UHPC top plate, the UHPC web stiffener is vertically arranged at a side wall of the UHPC web, and the UHPC bottom plate stiffener is vertically arranged at an upper portion of the UHPC bottom plate.

In the above large cantilever ultra-wide UHPC box girder unit, preferably, the UHPC web plate includes an UHPC inner web plate and an UHPC outer web plate, the UHPC outer web plate is disposed on both sides of the transverse direction of the box-type structure, the UHPC inner web plate is disposed at the center of the longitudinal direction of the box-type structure, the thickness of each of the UHPC inner web plate and the UHPC outer web plate is 0.15-0.50m, the thickness of the UHPC base plate is 0.15-1.20m, the thickness of the UHPC cross partition plate is 0.15-0.40m, the UHPC cross partition plate is disposed one by one along the longitudinal direction at intervals of 2-6m, and the height of the UHPC cross partition plate is 0.50-1.50m. The setting of the process parameters is determined based on the span and the bridge width of the engineering background bridge, so that the material can be saved, the high-strength characteristic of the UHPC is fully utilized, the local rigidity is enhanced, and the bridge manufacturing cost is reduced.

The large cantilever ultra-wide UHPC box girder unit can be of a single-box multi-chamber structure, when the single-box multi-chamber structure is adopted, the UHPC web plates comprise UHPC outer web plates positioned on two sides and UHPC inner web plates positioned in the box-type structure, the torsional rigidity of the box girder is greatly improved due to the existence of the UHPC inner web plates, and at the moment, part of UHPC transverse partition plates only need to stiffen the top plate and the bottom plate.

In the above large cantilever ultra-wide UHPC box girder unit, preferably, the UHPC flange and the UHPC box girder body are integrally formed, a tensile steel bar extending into the UHPC box girder body is pre-embedded in the UHPC outrigger, the UHPC diaphragm plate includes a UHPC top plate stiffener having a height not less than that of the UHPC outrigger, one end of the tensile steel bar is embedded in the UHPC outrigger, and the other end of the tensile steel bar penetrates through the UHPC web plate and extends into the UHPC top plate stiffener.

In the above-mentioned super wide UHPC case roof beam unit of big cantilever, it is preferred, same UHPC outrigger department is pre-buried to be equipped with many tensile reinforcement along the equidistant setting of co-altitude not, tensile reinforcement includes first main muscle and locates the first end hook at first main muscle both ends, it is same first end hook at first main muscle both ends is along the mid point symmetry of first main muscle sets up, and is adjacent from top to bottom the first main muscle dislocation set of tensile reinforcement. The staggered arrangement means that the first main ribs which are adjacent up and down are located at different longitudinal bridge directions, and more preferably, the longitudinal bridge directions of the first main ribs which are spaced are kept the same.

Because the UHPC box girder is mostly of a thin-wall structure, the transverse prestress is adopted, the process is complex, and proper position arrangement is lacked, the large cantilever ultra-wide UHPC box girder unit only needs to be provided with tensile reinforcements without being provided with transverse prestress bundles, the connection between the UHPC flange and the UHPC transverse clapboard is strengthened, the transverse rigidity of the ultra-wide box girder unit is improved, and the transverse rigidity is enough to resist the cantilever effect of the flange plate. The tensile steel bar is in a staggered steel bar structure with equal distribution, the end part of the tensile steel bar is reinforced by adopting a first end hook (such as a 180-degree hook), a first main steel bar with the first end hook does not need a complex processing mode, the structure is simple, the end part adopts a hook form, the end part pull-out resistance can be greatly improved, the end part anchoring force is strong, the staggered arrangement can more effectively utilize the contact surface of the steel bar and a UHPC matrix, the bonding force is improved, the stress is more uniform, and the box girder structure is particularly suitable for the assembly type construction. The UHPC cantilever beam is integrally reinforced by the first main rib with the first end hook and the UHPC diaphragm plate which are arranged in a staggered manner, and the main load transfer path of the UHPC flange is as follows: flange → outrigger → reinforcing bar → diaphragm → box girder main part, the power transmission route is reliable and stable, and the atress is simple, can effectively avoid the decking fracture.

In the above large cantilever ultra-wide UHPC box girder unit, preferably, the UHPC flange, the UHPC outrigger and the UHPC box girder body are connected by a cast-in-place UHPC wet joint, upper oblique notches corresponding to the UHPC flange and lower grooves corresponding to the UHPC outrigger are provided at upper portions of two lateral sides of the UHPC box girder body, and the cast-in-place UHPC wet joint is formed by casting the UHPC in the upper oblique notches and the lower grooves.

In the above large cantilever ultra-wide UHPC box girder unit, preferably, the UHPC box girder body is pre-embedded with second reserved steel bars at both upper bevel and lower groove, the second reserved steel bars at the upper bevel are uniformly provided with a plurality of second reserved steel bars, one end of each second reserved steel bar is arranged in the UHPC top plate, the other end of each second reserved steel bar extends into the cast-in-situ UHPC wet joint, the UHPC cross slab comprises UHPC top plate stiffening ribs with the height not less than that of the UHPC cantilever beam, the second reserved steel bars at the lower groove are arranged at equal intervals along different heights, one end of each second reserved steel bar is arranged in the UHPC top plate stiffening ribs, and the other end of each second reserved steel bar extends into the cast-in-situ UHPC wet joint; and a third reserved steel bar is arranged at the position, corresponding to the second reserved steel bar at the upper bevel, of the UHPC flange, one end of the third reserved steel bar in the UHPC flange is arranged in the UHPC flange, the other end of the third reserved steel bar extends into the cast-in-place UHPC wet joint, a third reserved steel bar is also arranged at the position, corresponding to the second reserved steel bar at the lower groove, of the UHPC cantilever beam, one end of the third reserved steel bar in the UHPC cantilever beam is arranged in the UHPC cantilever beam, and the other end of the third reserved steel bar extends into the cast-in-place UHPC wet joint.

In the above-mentioned big cantilever super wide UHPC box girder unit, preferably, the second reserved steel bar includes second main muscle, the one end that the second main muscle is close to the wet seam of cast-in-place UHPC is equipped with the second end hook, the third reserved steel bar includes the third main muscle, the one end that the third main muscle is close to the wet seam of cast-in-place UHPC is equipped with the third end hook, the horizontal bridge is adjacent second main muscle and third main muscle dislocation arrangement from top to bottom, and the second end hook and the third end hook all cross the vertical bridge of the wet seam of cast-in-place UHPC to the central line.

In the above large cantilever ultra-wide UHPC box girder unit, preferably, a pre-stressed tendon arranged in the through length direction of the cross bridge is further provided between the UHPC outrigger and the UHPC box girder body, the UHPC diaphragm includes a UHPC top plate stiffener having a height not less than that of the UHPC outrigger, both ends of the pre-stressed tendon are respectively anchored to the end portions of the UHPC outrigger (respectively located in the UHPC outriggers on the lateral side of the cross bridge, and located at the end portion on the lateral outermost side of the UHPC outrigger), and the middle portion of the pre-stressed tendon passes through the UHPC top plate stiffener.

Because the UHPC box girder is mostly of a thin-wall structure, the transverse prestress is adopted, the process is complex, and proper position arrangement is lacked. The reserved steel bars are of a vertically staggered steel bar structure, the end parts of the reserved steel bars are reinforced by end hooks (such as 180-degree hooks), a main steel bar with the end hooks does not need a complex processing mode, the structure is simple, the end parts can greatly improve the end part pull-out resistance by adopting the hook mode, the end part anchoring force is strong, the staggered arrangement can more effectively utilize the contact surface of the steel bars and a UHPC matrix, the bonding force is improved, the stress is more uniform, the force transmission path is stable and reliable, the stress is simple, the bridge deck can be effectively prevented from cracking, and the box girder structure is particularly suitable for the assembly type construction.

In the above large cantilever ultra-wide UHPC box girder unit, preferably, the width of the UHPC box girder body in the transverse bridge direction is 15 to 40m, the width of the UHPC flange in the transverse bridge direction is 5 to 10m, and the UHPC flanges are arranged symmetrically along the longitudinal bridge direction of the UHPC box girder body. The transverse bridge width of the UHPC box girder body is 15-40m, the transverse bridge width of the UHPC flange is 5-10m, the width of the whole box girder can reach 20-50m, and the width of the bridge is wider.

In the above large-cantilever ultra-wide UHPC box girder unit, preferably, the UHPC outriggers are symmetrically arranged along a longitudinal bridge direction to a center, the thickness of the UHPC outriggers is 0.1 to 0.8m, the transverse bridge direction width of the UHPC outriggers is 5 to 10m, the height of the UHPC outriggers is higher as the UHPC outriggers get closer to the UHPC box girder body, the height of a higher side is 2 to 5m, the height of a lower side is 0.1 to 0.6m, and a longitudinal bridge direction interval between centers of the adjacent UHPC outriggers is 2 to 6m.

In the above large cantilever ultra-wide UHPC box girder unit, preferably, the UHPC longitudinal ribs are inverted trapezoids with a wide top and a narrow bottom, the height of the UHPC longitudinal ribs is 0.2 to 0.8m, the width of the upper edges of the UHPC longitudinal ribs is 0.3 to 0.8m, the width of the lower edges of the UHPC longitudinal ribs is 0.2 to 0.6m, and the transverse bridge distance between the centers of the adjacent UHPC longitudinal ribs is 0.3 to 1.5m.

The technical parameters of the UHPC outriggers and the UHPC longitudinal ribs are set to be beneficial to the UHPC outriggers and the UHPC longitudinal ribs to be matched with the UHPC box girder body to play a role, so that the width of a bridge deck is greatly increased, the rigidity of a flange plate of the box girder is improved, and the cracking of a bridge deck is effectively avoided.

As a general technical concept, the invention also provides a large-cantilever ultra-wide UHPC box girder bridge which comprises a bridge pier and a plurality of large-cantilever ultra-wide UHPC box girder units, wherein the large-cantilever ultra-wide UHPC box girder units are assembled and combined into a whole along the longitudinal bridge direction through a prestress system.

In the large cantilever ultra-wide UHPC box girder bridge, preferably, the prestressed system includes an internal prestressed tendon and an external prestressed tendon, the internal prestressed tendon is embedded in the UHPC longitudinal rib along the longitudinal direction of the bridge, the external prestressed tendon passes through the UHPC diaphragm along the longitudinal direction of the bridge, the external prestressed tendon is anchored by an integrated external tendon block and turns by an integrated external tendon turning block, and the external tendon block and the external tendon turning block are both embedded and fixed on the UHPC diaphragm and fixed to the inner side wall of the UHPC web. The internal prestressed bundles are embedded in the UHPC longitudinal ribs, so that the local bending resistance bearing capacity of the UHPC flange can be greatly improved, the rigidity of the UHPC flange is improved to a certain extent, the deformation of the box girder is reduced, and the bridge deck is prevented from cracking.

As a general technical concept, the invention also provides a construction method of the large cantilever ultra-wide UHPC box girder bridge, which comprises the following steps:

s1: constructing a pile foundation and a pier;

s2: installing a 0# large cantilever ultra-wide UHPC box girder unit segment on a bridge pier, symmetrically assembling other large cantilever ultra-wide UHPC box girder unit segments on two sides of the installed large cantilever ultra-wide UHPC box girder unit segment according to the tensioning sequence of a prestress system, and completing the tensioning of the corresponding prestress system;

s3: firstly, folding a side span, then removing the temporary consolidation of the 0# large cantilever ultra-wide UHPC box girder unit section, finally folding a mid-span, and tensioning a prestressed system in the full-bridge span;

s4: and (4) completing the auxiliary engineering of the large cantilever ultra-wide UHPC box girder bridge and the bridge deck pavement, namely completing the construction.

In the prior art, the problem of bridge deck cracking cannot be well solved by adopting a steel box girder or a combined box girder structure (steel-concrete combined girder), and the problems in the aspects of construction and the like are also brought. Due to the excellent mechanical property and the super-strong durability of the ultra-high performance concrete (UHPC), the existing engineering practice shows that the UHPC is applied to bridge engineering, can greatly reduce the structure size and improve the local rigidity of a bridge, and is beneficial to the assembly construction. Therefore, the ultra-wide box girder bridge based on the UHPC material is expected to solve the technical problems of the traditional ultra-wide girder bridge.

The UHPC adopted by the invention has high strength and high toughness, and can avoid the local cracking of the bridge deck. In addition, in the longitudinal direction of the bridge, the bottom surface of the UHPC flange is stiffened by adopting UHPC longitudinal ribs and prestressed bundles embedded in the longitudinal ribs, so that the bending strength is greatly improved; in the transverse bridge direction, the UHPC cantilever beams are connected with the UHPC box girder body, and then the connection between the UHPC cantilever beams and the UHPC transverse partition plates is enhanced through the tensile reinforcing steel bars arranged in a staggered manner, so that the integral stability is enhanced; or in the transverse bridge direction, the flange of the UHPC, the UHPC cantilever beam and the UHPC box girder body are connected into a whole through a UHPC wet joint containing reserved staggered reinforcing steel bars, and then the connection between the UHPC cantilever beam and the UHPC box girder body is enhanced through the transverse bridge direction prestressed reinforcing steel bars, so that the integral stability is enhanced; and, the whole torsional rigidity can be enhanced by arranging the UHPC inner web plate. The load on the bridge deck can be well transferred to the UHPC box girder body from the UHPC flange under the synergistic effect of a plurality of factors, and the possibility of cracking of the bridge deck is favorably reduced.

Compared with the prior art, the invention has the advantages that:

1. the large-cantilever ultra-wide UHPC box girder unit provided by the invention is based on the excellent mechanical property of UHPC, and provides a structure of the large-cantilever ultra-wide UHPC box girder unit, which comprises a UHPC box girder body, UHPC outriggers and UHPC longitudinal ribs, so that a thin-wall structure can be adopted, the rigidity of a box girder flange plate can be greatly increased due to the mutual matching of the components, the total width of the box girder can reach 50m, and the requirements of ultra-large traffic flow and high road grade are met.

2. The large cantilever ultra-wide UHPC box girder unit has wider UHPC flanges, and is suitable for pier abutments with smaller transverse intervals, in particular to viaducts with tight urban land and sea-crossing bridges with poor offshore geological conditions.

3. The large cantilever ultra-wide UHPC box girder unit provided by the invention is a prefabricated structure made of UHPC materials, can realize the lightening of the prefabricated structure, enables the prefabrication, assembly and transportation of the structure to be easier, basically realizes the full-assembly construction, does not need to weld a steel box girder structure on site, greatly reduces the on-site workload and reduces the construction risk. In addition, compared with the traditional concrete beam bridge, the bridge based on UHPC as the main material can adopt lighter and thinner plate thickness and structural height, can be widely applied to the bridge with requirements on structural clearance (under-bridge clearance and navigation clearance), and has wide applicability. In addition, the axial tensile strength of the adopted UHPC material can reach more than 10MPa, the structural size of the bridge can be greatly reduced, the weight of the upper structure is reduced, the structural load resistance efficiency and the structural durability are improved, compared with a steel box girder bridge type scheme, the later-stage rust removal and cracking of a box girder main body are avoided, the later-stage operation and maintenance cost is reduced, and the economy is good.

Drawings

In order to more clearly illustrate the embodiments or technical solutions of the present invention, the drawings used in the embodiments or technical solutions in the prior art are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a large-cantilever ultra-wide UHPC box beam unit in embodiment 1.

Fig. 2 is a schematic structural diagram of another angle of the large cantilever ultra-wide UHPC box girder unit in fig. 1.

Fig. 3 is a schematic diagram of the arrangement of the prestressing force of the large cantilever ultra-wide UHPC box girder unit in embodiment 1.

Fig. 4 is a schematic cross-sectional structural view of a large-cantilever ultra-wide UHPC box girder unit including UHPC outriggers and UHPC diaphragms in embodiment 1.

Fig. 5 is a schematic cross-sectional structural view of a large-cantilever ultra-wide UHPC box girder unit in example 1 without UHPC outriggers and UHPC diaphragms.

Fig. 6 is a schematic cross-sectional structure view of a large cantilever ultra-wide UHPC box girder unit comprising UHPC outriggers and another type of UHPC diaphragm plate (only comprising UHPC top plate stiffener plates) in example 1.

Fig. 7 is a schematic view of arrangement of tensile steel bars of a large cantilever ultra-wide UHPC box girder unit in embodiment 1.

Fig. 8 is a schematic view showing the arrangement of the tension bars in example 1.

Fig. 9 is a schematic structural diagram of a large cantilever ultra-wide UHPC box girder bridge in embodiment 1.

Fig. 10 is a schematic structural diagram of a large cantilever ultra-wide UHPC box beam unit in embodiment 2.

Fig. 11 is a schematic layout view of the second and third pre-stressed steel bars and the pre-stressed steel bars in embodiment 2.

Fig. 12 is a schematic structural view of a transverse bridge of a UHPC box girder body in embodiment 2.

Fig. 13 is a schematic view of the structure of the UHPC outriggers and the side surfaces at the UHPC flange in example 2.

Fig. 14 is a schematic view of the structure of fig. 12 and 13 combined together.

Fig. 15 is a partially enlarged view of a in fig. 14.

Illustration of the drawings:

1. a bridge pier; 21. a UHPC box girder body; 211. a UHPC ceiling panel; 212. an UHPC inner web; 213. an UHPC outer web; 214. a UHPC backplane; 215. a UHPC diaphragm plate; 22. UHPC outrigger; 23. UHPC longitudinal ribs; 24. a UHPC flange; 3. a pre-stress system; 31. an external prestressing tendon; 32. an in-vivo prestressed tendon; 33. an external binding tooth block; 34. an in vitro beam steering block; 4. tensile steel bars; 41. a first main rib; 42. a first end hook; 5. casting UHPC wet joint in situ; 51. an upper bevel opening; 52. a lower groove; 6. second reserved steel bars; 61. a second main rib; 62. a second end hook; 7. thirdly, reserving reinforcing steel bars; 71. a third main rib; 72. a third end hook; 8. and (4) prestressed tendons.

Detailed Description

In order to facilitate an understanding of the invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Example 1:

as shown in fig. 1-2 and 4-6, the large cantilever ultra-wide UHPC box girder unit of this embodiment is a prefabricated structure, and includes a UHPC box girder body 21, UHPC flanges 24 extending outward are provided on both sides of a cross bridge on the upper surface of the UHPC box girder body 21, a plurality of UHPC outriggers 22 arranged at intervals are provided between the side surface of the UHPC box girder body 21 and the bottom surface of the UHPC flanges 24, a plurality of UHPC longitudinal ribs 23 arranged at intervals are arranged below the UHPC flanges 24, the UHPC outriggers 22 are arranged along the cross bridge direction, and the UHPC longitudinal ribs 23 are arranged along the longitudinal bridge direction.

In this embodiment, the UHPC box girder body 21 includes a UHPC top plate 211, a UHPC bottom plate 214, a UHPC cross-partition plate 215, and a UHPC web plate disposed along a longitudinal bridge direction, which are all flat plate members, the UHPC web plate is disposed between the UHPC top plate 211 and the UHPC bottom plate 214 to form a box-type structure (illustrated as a single-box double-chamber structure in this embodiment), the UHPC cross-partition plate 215 includes UHPC top plate stiffeners, UHPC web plate stiffeners, and UHPC bottom plate stiffeners, the UHPC top plate stiffeners are vertically disposed at the bottom of the UHPC top plate 211, the UHPC web stiffeners are vertically disposed on side walls of the pc UHPC web plate, and the pc bottom plate stiffeners are vertically disposed on the upper portion of the UHPC bottom plate 214.

Specifically, in this embodiment, the UHPC web plates include an UHPC inner web plate 212 and an UHPC outer web plate 213, the UHPC outer web plates 213 are disposed on both sides of the horizontal direction of the box-shaped structure, the UHPC inner web plate 212 is disposed in the center of the vertical direction of the box-shaped structure, the thicknesses of the UHPC inner web plate 212 and the UHPC outer web plate 213 are both 0.15 to 0.50m (both the above ranges, for example, 0.2 m), the thickness of the UHPC bottom plate 214 is 0.15 to 1.20m (both the above ranges, for example, 0.2 m), the thickness of the UHPC cross partition plate 215 is 0.15 to 0.40m (both the above ranges, for example, 0.2 m), the UHPC cross partition plate 215 is disposed at intervals of 2 to 6m (both the above ranges, for example, 3 m) along the vertical direction, and the height of the UHPC cross partition plate 215 is 0.50 to 1.50m (both the above ranges, for example, 1 m).

Of course, as shown in FIG. 6, in this embodiment, the UHPC bulkhead 215 may include only UHPC roof stiffeners, as the case may require.

As shown in fig. 8 and 9, in this embodiment, a tensile steel bar 4 extending into the UHPC box girder body 21 is pre-embedded in the UHPC outrigger 22, the UHPC diaphragm 215 includes a UHPC top plate stiffener having a height not less than that of the UHPC outrigger 22, one end of the tensile steel bar 4 is embedded in the UHPC outrigger 22, and the other end of the tensile steel bar passes through the UHPC web and extends into the UHPC top plate stiffener. Specifically, as shown in fig. 9, in this embodiment, a plurality of tensile steel bars 4 arranged at equal intervals along different heights are embedded in the same UHPC outrigger 22, each tensile steel bar 4 includes a first main bar 41 and first end hooks 42 arranged at two ends of the first main bar 41, the first end hooks 42 at two ends of the same first main bar 41 are symmetrically arranged along the middle point of the first main bar 41, and the first main bars 41 of the upper and lower adjacent tensile steel bars 4 are arranged in a staggered manner.

In this embodiment, the width of the UHPC box girder body 21 in the transverse direction is 15 to 40m, the width of the UHPC flange 24 in the transverse direction is 5 to 10m, the UHPC flanges 24 are symmetrically arranged along the longitudinal bridge direction of the UHPC box girder body 21, and the UHPC flanges 24 are integrally formed with the UHPC box girder body 21.

In this embodiment, the UHPC outriggers 22 are symmetrically arranged along the longitudinal bridge direction, the size is fixed, the thickness of the UHPC outriggers 22 is 0.1 to 0.8m (any range, such as 0.3m is adopted), the transverse bridge direction width of the UHPC outriggers 22 is 5 to 10m (any range, such as 8m is adopted), the height of the UHPC outriggers 22 is higher as they approach the UHPC box girder body 21, the height of the higher side is 2 to 5m (any range, such as 3m is adopted), the height of the lower side is 0.1 to 0.6m (any range, such as 0.1m is adopted), and the longitudinal bridge direction distance between the centers of adjacent UHPC outriggers 22 is 2 to 6m (any range, such as 4m is adopted).

In this embodiment, the UHPC longitudinal ribs 23 are inverted trapezoids having a wide top and a narrow bottom, the height of the UHPC longitudinal ribs 23 is 0.2-0.8m (any range can be used, for example, 0.4 m), the width of the upper edge of the UHPC longitudinal ribs 23 is 0.3-0.8m (any range can be used, for example, 0.5 m), the width of the lower edge of the UHPC longitudinal ribs 23 is 0.2-0.6m (any range can be used, for example, 0.4 m), and the transverse bridging distance between the centers of adjacent UHPC longitudinal ribs 23 is 0.3-1.5m (any range can be used, for example, 1.5 m).

As shown in fig. 10, the large-cantilever ultra-wide UHPC box girder bridge of this embodiment includes a pier 1 and a plurality of the above-mentioned large-cantilever ultra-wide UHPC box girder units, and the plurality of large-cantilever ultra-wide UHPC box girder units are assembled and combined into a whole along a longitudinal bridge direction by a prestressed system 3.

Specifically, the large cantilever ultra-wide UHPC box girder bridge is a continuous girder bridge type, the span arrangement can be 75m +130m +75m, a large cantilever ultra-wide UHPC box girder unit is adopted in a full-bridge upper structure, and a prestress system 3 adopts a mixed stress system of an external prestress beam 31 and an internal prestress beam 32 in the longitudinal direction of the box girder. In this example, the axial tensile strength of UHPC was 10MPa or more and the compressive strength was 120MPa or more.

As shown in fig. 3, in the present embodiment, the prestressed system 3 includes an internal prestressed tendon 32 and an external prestressed tendon 31, the internal prestressed tendon 32 is embedded in the UHPC longitudinal rib 23 along the longitudinal direction, the external prestressed tendon 31 passes through the UHPC bulkhead 215 along the longitudinal direction, the external prestressed tendon 31 is anchored by an external tendon block 33 and is turned by an external tendon turning block 34, which can resist the radial force generated by the turning of the external prestressed tendon 31, and both the external tendon block 33 and the external tendon turning block 34 are embedded in the UHPC bulkhead 215 and are fixed to the inner sidewall of the UHPC web. Specifically, in this embodiment, the external prestressing tendons 31 pass through the UHPC top plate stiffener of the UHPC diaphragm 215 along the longitudinal direction, the external tendon steering block 34 is fixed on the UHPC top plate stiffener and the side surface thereof is fixedly connected with the UHPC external web 213, and the external tendon tooth block 33 is fixed on the UHPC bottom plate stiffener and the side surface thereof is fixedly connected with the UHPC external web 213.

The construction method of the large cantilever ultra-wide UHPC box girder bridge comprises the following steps:

s1: constructing a pile foundation and a pier 1; prefabricating a large cantilever ultra-wide UHPC box girder unit in a factory;

s2: installing a 0# large cantilever ultra-wide UHPC box girder unit segment on a pier 1, assembling other large cantilever ultra-wide UHPC box girder unit segments on two sides of the installed large cantilever ultra-wide UHPC box girder unit segment symmetrically according to the tensioning sequence of a prestress system 3, and completing the tensioning of the corresponding prestress system 3;

s3: folding the side span, then removing the temporary consolidation of the 0# large cantilever ultra-wide UHPC box girder unit section, folding the middle span, and tensioning the prestress system 3 in the full-bridge span;

s4: and (4) completing the auxiliary engineering of the large cantilever ultra-wide UHPC box girder bridge and the bridge deck pavement, namely completing the construction.

The big cantilever super-wide UHPC box girder unit and the big cantilever super-wide UHPC box girder bridge provided by the embodiment have the advantages of light weight, high strength, simplicity and convenience in construction, reasonable stress, capability of greatly improving the local rigidity of the flange of the box girder, super-wide bridge deck, good economical efficiency and wide applicability, and are particularly suitable for urban viaducts or river-crossing and sea-crossing bridges with navigation clearance requirements.

Example 2:

the large cantilever ultra-wide UHPC box girder unit is of a prefabricated structure and comprises an UHPC box girder body 21, UHPC flanges 24 extending outwards are arranged on two sides of a transverse bridge on the upper surface of the UHPC box girder body 21, a plurality of UHPC outriggers 22 arranged at intervals are arranged between the side surface of the UHPC box girder body 21 and the bottom surface of the UHPC flange 24, a plurality of UHPC longitudinal ribs 23 arranged at intervals are arranged below the UHPC flanges 24, the UHPC outriggers 22 are arranged along the transverse bridge direction, and the UHPC longitudinal ribs 23 are arranged along the longitudinal bridge direction.

The structure of the UHPC box girder body 21, the UHPC flange 24, the UHPC outrigger 22 and the UHPC longitudinal rib 23 in this embodiment are similar to those in embodiment 1, and the difference is that: as shown in fig. 10-15, the UHPC flange 24, the UHPC outrigger 22 and the UHPC box girder body 21 are connected by a cast-in-situ UHPC wet joint 5, the upper parts of the two lateral sides of the UHPC box girder body 21 are provided with an upper bevel 51 corresponding to the UHPC flange 24 and a lower groove 52 corresponding to the UHPC outrigger 22, and the UHPC is cast in situ in the upper bevel 51 and the lower groove 52 to form the cast-in-situ UHPC wet joint 5.

In this embodiment, the UHPC box girder body 21 is pre-buried with second reserved steel bars 6 at the upper bevel 51 and the lower groove 52, the second reserved steel bars 6 at the upper bevel 51 are uniformly provided with a plurality of steel bars, one end of each steel bar is arranged in the UHPC top plate 211, the other end of each steel bar extends into the cast-in-situ UHPC wet joint 5, the UHPC cross slab 215 comprises UHPC top plate stiffening ribs with the height not less than that of the UHPC outriggers 22, the second reserved steel bars 6 at the lower groove 52 are arranged at equal intervals along different heights, one end of each steel bar is arranged in the UHPC top plate stiffening ribs, and the other end of each steel bar extends into the cast-in-situ UHPC wet joint 5; a third reserved steel bar 7 is arranged at the position, corresponding to the second reserved steel bar 6, of the upper bevel opening 51 of the UHPC flange 24, one end of the third reserved steel bar 7 in the UHPC flange 24 is arranged in the UHPC flange 24, the other end of the third reserved steel bar 7 extends into the cast-in-place UHPC wet joint 5, a third reserved steel bar 7 is also arranged at the position, corresponding to the second reserved steel bar 6, of the lower groove 52 of the UHPC cantilever beam 22, one end of the third reserved steel bar 7 in the UHPC cantilever beam 22 is arranged in the UHPC cantilever beam 22, and the other end of the third reserved steel bar 7 extends into the cast-in-place UHPC wet joint 5.

In this embodiment, the second reserved steel bar 6 includes the second main bar 61, the one end that the second main bar 61 is close to the wet seam 5 of cast-in-place UHPC is equipped with the second end hook 62, the third reserved steel bar 7 includes the third main bar 71, the one end that the third main bar 71 is close to the wet seam 5 of cast-in-place UHPC is equipped with the third end hook 72, horizontal bridge is to adjacent second main bar 61 and third main bar 71 dislocation arrangement from top to bottom, and the second end hook 62 and the third end hook 72 all cross the vertical bridge of the wet seam 5 of cast-in-place UHPC to the central line.

In this embodiment, a prestressed tendon 8 arranged along the axial length of the cross bridge is further arranged between the UHPC outrigger 22 and the UHPC box girder body 21, the UHPC diaphragm 215 includes a UHPC top plate stiffener having a height not less than that of the UHPC outrigger 22, two ends of the prestressed tendon 8 are respectively anchored to the end of the UHPC outrigger 22, and the middle of the prestressed tendon 8 penetrates through the UHPC top plate stiffener.

The large-cantilever ultra-wide UHPC box girder bridge comprises a bridge pier 1 and the large-cantilever ultra-wide UHPC box girder units, wherein the large-cantilever ultra-wide UHPC box girder units are assembled and combined into a whole along the longitudinal bridge direction through a prestress system 3. The prestressing system 3 and the like of this embodiment may be similar to those of embodiment 1.

The construction method of the large cantilever ultra-wide UHPC box girder bridge comprises the following steps:

s1: constructing a pile foundation and a pier 1; respectively prefabricating a UHPC box girder body 21 and a UHPC cantilever girder (wherein a UHPC flange 24 and the UHPC cantilever girder 22 are integrally formed) in a factory;

s2: installing a No. 0 UHPC box girder body 21 section on a pier 1, symmetrically assembling other UHPC box girder body 21 sections on two sides of the installed UHPC box girder body 21 section according to the tensioning sequence of a prestress system 3, completing the assembly of the UHPC box girder body 21 section according to the sequence of side span folding and mid-span folding, and completing the tensioning of the corresponding prestress system 3;

s3: then, installing all UHPC cantilever beams at the appointed positions on two sides of the UHPC box girder body 21 through temporary constraint, pouring early-strength UHPC to form a cast-in-place UHPC wet joint 5, stretching a prestressed tendon 8 in the transverse bridge direction to ensure the connection of the UHPC box girder body 21 and the UHPC cantilever beams 22 after the cast-in-place UHPC wet joint 5 reaches a certain strength, and removing the temporary constraint;

s4: dismantling the temporary consolidation of the 0# large cantilever ultra-wide UHPC box girder unit section, and tensioning a prestressed system 3 in the full-bridge span;

s5: and (4) completing the auxiliary engineering of the large cantilever ultra-wide UHPC box girder bridge and the bridge deck pavement, namely completing the construction.

Claims (7)

1. The large cantilever ultra-wide UHPC box girder unit is characterized by comprising an UHPC box girder body (21), wherein UHPC flanges (24) extending outwards are arranged on two sides of a transverse bridge on the upper surface of the UHPC box girder body (21), a plurality of UHPC outriggers (22) arranged at intervals are arranged between the side surface of the UHPC box girder body (21) and the bottom surface of the UHPC flange (24), a plurality of UHPC longitudinal ribs (23) arranged at intervals are arranged below the UHPC flange (24), the UHPC outriggers (22) are arranged along the transverse bridge direction, and the UHPC longitudinal ribs (23) are arranged along the longitudinal bridge direction;

the UHPC box girder body (21) comprises an UHPC top plate (211), an UHPC bottom plate (214), an UHPC transverse clapboard (215) and UHPC webs arranged along a longitudinal bridge direction, wherein the UHPC webs are arranged between the UHPC top plate (211) and the UHPC bottom plate (214) to form a box-type structure, the UHPC transverse clapboard (215) comprises at least one of UHPC top plate stiffening ribs, UHPC web stiffening ribs and UHPC bottom plate stiffening ribs, the UHPC top plate stiffening ribs are vertically arranged at the bottom of the UHPC top plate (211), the UHPC web stiffening ribs are vertically arranged at the side walls of the UHPC webs, and the UHPC bottom plate stiffening ribs are vertically arranged at the upper part of the UHPC bottom plate (214);

the UHPC flange (24) and the UHPC box girder body (21) are integrally formed, or the UHPC flange (24), the UHPC cantilever beam (22) and the UHPC box girder body (21) are connected through a cast-in-place UHPC wet joint (5);

when the UHPC flange (24) and the UHPC box girder body (21) are integrally formed, a tensile steel bar (4) extending into the UHPC box girder body (21) is pre-buried in the UHPC outrigger (22), the UHPC transverse diaphragm plate (215) comprises UHPC top plate stiffening ribs with the height not less than that of the UHPC outrigger (22), one end of the tensile steel bar (4) is buried in the UHPC outrigger (22), and the other end of the tensile steel bar penetrates through the UHPC web plate and extends into the UHPC top plate stiffening ribs;

when the UHPC flange (24), the UHPC cantilever beam (22) and the UHPC box girder body (21) are connected through a cast-in-place UHPC wet joint (5), the upper parts of two sides of the transverse bridge of the UHPC box girder body (21) are provided with an upper bevel connection (51) corresponding to the UHPC flange (24) and a lower groove (52) corresponding to the UHPC cantilever beam (22), and the UHPC is cast in place in the upper bevel connection (51) and the lower groove (52) to form the cast-in-place UHPC wet joint (5); and prestressed tendons (8) arranged along the transverse bridge direction to the full length are further arranged between the UHPC outriggers (22) and the UHPC box girder body (21), each UHPC diaphragm plate (215) comprises UHPC top plate stiffening ribs with the height not less than that of each UHPC outrigger (22), two ends of each prestressed tendon (8) are respectively anchored at the end parts of each UHPC outrigger (22), and the middle part of each prestressed tendon (8) penetrates through each UHPC top plate stiffening rib.

2. The large cantilever ultra-wide UHPC box girder unit according to claim 1, wherein the UHPC web plates comprise an UHPC inner web plate (212) and an UHPC outer web plate (213), the UHPC outer web plates (213) are arranged at two sides of the box structure in the transverse direction of the box structure, the UHPC inner web plate (212) is arranged at the center of the box structure in the longitudinal direction of the box structure, the thickness of the UHPC inner web plate (212) and the thickness of the UHPC outer web plate (213) are both 0.15-0.50m, the thickness of the UHPC bottom plate (214) is 0.15-1.20m, the thickness of the UHPC transverse partition plate (215) is 0.15-0.40m, the UHPC transverse partition plates (215) are arranged at intervals of 2-6m in the longitudinal direction, and the height of the UHPC transverse partition plate (215) is 0.50-1.50m.

3. The large-cantilever ultra-wide UHPC box girder unit is characterized in that a plurality of tensile steel bars (4) which are arranged at equal intervals along different heights are pre-buried at the same UHPC cantilever beam (22), each tensile steel bar (4) comprises a first main bar (41) and first end hooks (42) which are arranged at two ends of the first main bar (41), the first end hooks (42) at two ends of the same first main bar (41) are symmetrically arranged along the middle point of the first main bar (41), and the first main bars (41) of the tensile steel bars (4) are vertically adjacent and staggered.

4. The large-cantilever ultra-wide UHPC box girder unit according to claim 1, wherein a plurality of second reserved steel bars (6) are embedded in an upper bevel opening (51) and a lower groove (52) of the UHPC box girder body (21), one end of each of the plurality of second reserved steel bars (6) is arranged in the UHPC top plate (211), the other end of each of the plurality of second reserved steel bars extends into the cast-in-place UHPC wet joint (5), the UHPC transverse partition plate (215) comprises UHPC top plate stiffening ribs with the height not less than that of the cantilever beam (22), the plurality of second reserved steel bars (6) in the lower groove (52) are arranged at equal intervals along different heights, one end of each of the plurality of second reserved steel bars is arranged in the UHPC top plate stiffening ribs, and the other end of each of the plurality of second reserved steel bars extends into the cast-in-place UHPC wet joint (5); a third reserved steel bar (7) is arranged at the position, corresponding to the second reserved steel bar (6) at the upper bevel opening (51), of the UHPC flange (24), one end of the third reserved steel bar (7) in the UHPC flange (24) is arranged in the UHPC flange (24), the other end of the third reserved steel bar extends into the cast-in-situ UHPC wet joint (5), a third reserved steel bar (7) is also arranged at the position, corresponding to the second reserved steel bar (6) at the lower groove (52), of the UHPC cantilever beam (22), one end of the third reserved steel bar (7) in the UHPC cantilever beam (22) is arranged in the UHPC cantilever beam (22), and the other end of the third reserved steel bar extends into the cast-in-situ UHPC wet joint (5);

the second reserved steel bar (6) comprises a second main bar (61), a second end hook (62) is arranged at one end, close to the cast-in-situ UHPC wet joint (5), of the second main bar (61), the third reserved steel bar (7) comprises a third main bar (71), a third end hook (72) is arranged at one end, close to the cast-in-situ UHPC wet joint (5), of the third main bar (71), the second main bar (61) and the third main bar (71) are arranged in a transverse bridge mode in a vertically staggered mode, and the second end hook (62) and the third end hook (72) cross the longitudinal bridge direction center line of the cast-in-situ UHPC wet joint (5).

5. The large cantilever ultra-wide UHPC box girder unit according to any one of claims 1-4, wherein the transverse bridge width of the UHPC box girder body (21) is 15-40m, the transverse bridge width of the UHPC flange (24) is 5-10m, and the UHPC flanges (24) are arranged symmetrically along the longitudinal bridge direction of the UHPC box girder body (21);

the UHPC outriggers (22) are symmetrically arranged along the longitudinal bridge direction, the thickness of the UHPC outriggers (22) is 0.1-0.8m, the transverse bridge direction width of the UHPC outriggers (22) is 5-10m, the height of the UHPC outriggers (22) is higher when being closer to the UHPC box girder body (21), the height of the higher side is 2-5m, the height of the lower side is 0.1-0.6m, and the longitudinal bridge direction distance between the centers of the adjacent UHPC outriggers (22) is 2-6m;

the UHPC longitudinal ribs (23) are inverted trapezoids with wide upper parts and narrow lower parts, the height of the UHPC longitudinal ribs (23) is 0.2-0.8m, the width of the upper edge of each UHPC longitudinal rib (23) is 0.3-0.8m, the width of the lower edge of each UHPC longitudinal rib (23) is 0.2-0.6m, and the transverse bridge distance between the centers of the adjacent UHPC longitudinal ribs (23) is 0.3-1.5m.

6. A large cantilever ultra-wide UHPC box girder bridge is characterized by comprising a bridge pier (1) and large cantilever ultra-wide UHPC box girder units according to any one of claims 1 to 5, wherein a plurality of the large cantilever ultra-wide UHPC box girder units are assembled and combined into a whole along the longitudinal bridge direction through a prestress system (3);

the prestress system (3) comprises internal prestress tendons (32) and external prestress tendons (31), the internal prestress tendons (32) are embedded in the UHPC longitudinal ribs (23) along the longitudinal bridge direction, the external prestress tendons (31) penetrate through the UHPC transverse partition plate (215) along the longitudinal bridge direction, the external prestress tendons (31) are anchored through an integrated external tendon tooth block (33) and turned through an integrated external tendon turning block (34), and the integrated external tendon tooth block (33) and the external tendon turning block (34) are both embedded on the UHPC transverse partition plate (215) and are fixedly connected with the inner side wall of the UHPC web plate.

7. The construction method of the large-cantilever ultra-wide UHPC box girder bridge of claim 6, characterized by comprising the following steps:

s1: constructing a pile foundation and a pier (1);

s2: installing a 0# large cantilever ultra-wide UHPC box girder unit segment on a pier (1), symmetrically assembling other large cantilever ultra-wide UHPC box girder unit segments on two sides of the installed large cantilever ultra-wide UHPC box girder unit segment according to the tensioning sequence of a prestress system (3), and completing the tensioning of the corresponding prestress system (3);

s3: firstly, folding a side span, then removing the temporary consolidation of the 0# large cantilever ultra-wide UHPC box girder unit section, finally folding a mid-span, and tensioning a prestressed system (3) in the full-bridge span;

s4: and (4) completing the auxiliary engineering of the large cantilever ultra-wide UHPC box girder bridge and the bridge deck pavement, namely completing the construction.

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