阅读说明：本技术 一种磁悬浮uhpc箱梁 (Magnetic suspension UHPC case roof beam ) 是由 曾敏 文望青 周天喜 严爱国 胡方杰 王志平 曹文杰 夏正春 张玲 杨光 杨朝龙 于 2020-12-24 设计创作，主要内容包括：本发明公开了一种磁悬浮UHPC箱梁,包括箱梁顶板、箱梁底板以及设于两者之间的箱梁腹板；所述箱梁腹板横向之间间隔设有箱梁横肋,各箱梁横肋顶部与所述箱梁顶板固结,横向两端分别与所述箱梁腹板内侧固结,所述箱梁横肋位于箱梁顶板受压区域以防止薄板翘曲失稳；所述箱梁顶板、箱梁底板以及箱梁腹板均采用UHPC材料,以减少梁高以及箱梁顶板、底板、腹板的厚度。本发明适用于磁浮交通,箱梁顶板、底板、腹板采用UHPC材料,同时减少箱梁顶板、底板、腹板的厚度,在提高了刚度,满足高速磁浮对于桥梁结构严苛的变形要求的同时减小了截面方量,便于施工且减小了下部结构的用量,并且横肋及横隔板采用普通混凝土,降低结构了造价。(The invention discloses a magnetic suspension UHPC box girder, which comprises a box girder top plate, a box girder bottom plate and a box girder web plate arranged between the box girder top plate and the box girder bottom plate; box girder transverse ribs are arranged between the box girder web plates in the transverse direction at intervals, the top of each box girder transverse rib is fixedly connected with the box girder top plate, the two transverse ends of each box girder transverse rib are respectively fixedly connected with the inner sides of the box girder web plates, and the box girder transverse ribs are positioned in the compression areas of the box girder top plates to prevent the thin plates from warping and destabilizing; and the box girder top plate, the box girder bottom plate and the box girder web plate are all made of UHPC materials so as to reduce the height of the girder and the thickness of the box girder top plate, the box girder bottom plate and the box girder web plate. The invention is suitable for magnetic suspension traffic, the top plate, the bottom plate and the web plate of the box girder are made of UHPC materials, the thickness of the top plate, the bottom plate and the web plate of the box girder is reduced, the rigidity is improved, the severe deformation requirement of high-speed magnetic suspension on a bridge structure is met, the section square quantity is reduced, the construction is convenient, the consumption of a lower structure is reduced, and the cross ribs and the cross clapboards are made of common concrete, so that the construction cost is reduced.)

1. A magnetic suspension UHPC box girder is characterized by comprising a box girder top plate (1), a box girder bottom plate (2) and a box girder web plate (3) arranged between the box girder top plate and the box girder bottom plate;

box girder transverse ribs (6) are arranged between the box girder web plates (3) at intervals in the transverse direction, the top of each box girder transverse rib (6) is fixedly connected with the box girder top plate (1), the two transverse ends of each box girder transverse rib are fixedly connected with the inner sides of the box girder web plates (3) respectively, and the box girder transverse ribs (6) are positioned in the pressed areas of the box girder top plates to prevent thin plates from buckling and instability;

and the box girder top plate (1), the box girder bottom plate (2) and the box girder web plate (3) are all made of UHPC materials so as to reduce the height of the girder and the thickness of the box girder top plate, the box girder bottom plate and the box girder web plate.

2. The magnetic suspension UHPC box girder according to claim 1, characterized in that the bridge beam supports are provided with diaphragms (7), each diaphragm (7) is transversely fixed with the inner side of the box girder web plate (3), the top of the diaphragm is fixed with the inner side of the box girder top plate (1), and the bottom of the diaphragm is fixed with the box girder bottom plate (2).

3. The UHPC box girder according to claim 1 or 2, characterized in that two rail bearing girders (5) are arranged on the top of the box girder top plate (1) in a transverse symmetry manner according to the center line position of a double-line, and are used as running rails of a magnetic suspension train.

4. A magnetically suspended UHPC box girder according to claim 3, characterised in that the box girder top plate (1) has a thickness in the range of 0.15-0.25m and the box girder bottom plate (2) has a thickness in the range of 0.2-0.3 m.

5. The magnetically suspended UHPC box girder according to claim 1 or 4, characterised in that the box girder top plate (1) is extended on both lateral sides to form cantilever plates (4), the width of the cantilever plates (4) being 1-1.5m, respectively.

6. The magnetically suspended UHPC box girder according to claim 5, characterized in that the distance between the tops of the box girder webs (3) is 5-6m and the width of the box girder top plate (1) is 7-9 m.

7. The magnetically suspended UHPC box girder according to claim 1 or 6, characterised in that the box girder cross ribs (6) and the diaphragms (7) are of plain concrete.

8. The magnetically suspended UHPC box girder according to claim 7, characterised in that the box girder cross ribs (6) have a vertical height in the range of 1.5-2.5m and a longitudinal length in the range of 0.2-0.4m and are laterally matched to the two sides of the box girder web.

Technical Field

The invention belongs to the technical field of magnetic suspension rail transit, and particularly relates to a magnetic suspension UHPC box girder.

Background

The magnetic suspension traffic is a ground passenger traffic, and is obviously different from the traditional wheel-rail traffic system in that a vehicle body is suspended above a track by virtue of suspension force, and a walking part of the vehicle body is not in contact with the track. The propulsion generated by the linear induction motor travels on the track. The electrified suspension electromagnet on the suspension frame of the normally-conducting high-speed maglev train and the long stator coil on the track mutually attract each other to provide suspension force for the train, suck the train upwards, and ensure a stable suspension gap by controlling suspension exciting current. The levitation gap between the electromagnet and the rail is generally controlled to be about 10 mm.

The electrified guide electromagnet on the suspension frame interacts with the guide plate on the side surface of the track to provide a guide force, so that a certain lateral distance is kept between the vehicle body and the track, and the non-contact guide in the horizontal direction is realized. The high-speed maglev train is driven by a non-vehicle-mounted power device, namely a long stator Linear Synchronous Motor (LSM), a suspension electromagnet coil is arranged at the lower part of a vehicle suspension frame, a long stator coil is arranged on a track, and when the long stator coil arranged along the line direction provides three-phase frequency modulation and amplitude modulation power, the train is pushed to advance under the action of electromagnetic induction, so that the complete non-contact traction and braking of the train in a suspension state are realized.

At present, in magnetic levitation tests and business lines carried out by magnetic levitation in Germany, Japan, England, China and the like, a reinforced concrete structure is mainly used, and a steel structure form is adopted with a small amount of span and large span. When the span is increased, the conventional concrete structure is difficult to meet the severe deformation requirement of high-speed magnetic levitation on the bridge structure due to the characteristics of self shrinkage and creep and the like, the steel structure is high in manufacturing cost, the natural vibration frequency is difficult to meet the requirement, and meanwhile, a damper may need to be additionally arranged.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides the magnetic suspension UHPC box girder, wherein a top plate, a bottom plate and a web plate of the box girder are made of UHPC materials, and the thicknesses of the top plate, the bottom plate and the web plate of the box girder are reduced, so that the rigidity is improved, the severe deformation requirement of high-speed magnetic suspension on a bridge structure is met, the section square is reduced, the construction is convenient, and the using amount of a lower structure is reduced.

In order to achieve the aim, the invention provides a magnetic suspension UHPC box girder, which comprises a box girder top plate, a box girder bottom plate and a box girder web plate arranged between the box girder top plate and the box girder bottom plate;

box girder transverse ribs are arranged between the box girder web plates in the transverse direction at intervals, the top of each box girder transverse rib is fixedly connected with the box girder top plate, the two transverse ends of each box girder transverse rib are respectively fixedly connected with the inner sides of the box girder web plates, and the box girder transverse ribs are positioned in the compression areas of the box girder top plates to prevent the thin plates from warping and destabilizing;

and the box girder top plate, the box girder bottom plate and the box girder web plate are all made of UHPC materials so as to reduce the height of the girder and the thickness of the box girder top plate, the box girder bottom plate and the box girder web plate.

As a further improvement of the invention, the bridge support is provided with the transverse clapboards, each transverse clapboard is transversely fixedly connected with the inner side of the box girder web plate, the top of each transverse clapboard is fixedly connected with the inner side of the box girder top plate, and the bottom of each transverse clapboard is fixedly connected with the box girder bottom plate.

As a further improvement of the invention, two rail bearing beams are transversely and symmetrically arranged on the top of the box girder top plate according to the central line position of the double-line and are used as running tracks of the magnetic suspension train.

As a further improvement of the invention, the thickness of the box girder top plate ranges from 0.15m to 0.25m, and the thickness of the box girder bottom plate ranges from 0.2m to 0.3 m.

As a further improvement of the invention, the two lateral sides of the box girder top plate extend out to form cantilever plates, and the widths of the cantilever plates are respectively 1-1.5 m.

As a further improvement of the invention, the distance between the tops of the box girder web plates is 5-6m, and the width of the box girder top plate is 7-9 m.

As a further improvement of the invention, the box girder transverse ribs and the transverse clapboards are made of common concrete.

As a further improvement of the invention, the box girder transverse rib has a vertical height ranging from 1.5 to 2.5m and a longitudinal length ranging from 0.2 to 0.4m, and is matched with two sides of the box girder web plate in the transverse direction.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

(1) the magnetic suspension UHPC box girder is suitable for magnetic suspension traffic, the top plate, the bottom plate and the web plate of the box girder are made of UHPC materials, and meanwhile, the height of the box girder and the thickness of the top plate, the bottom plate and the web plate are reduced, so that the rigidity is improved, the severe deformation requirement of high-speed magnetic suspension on a bridge structure is met, the cross section square quantity is reduced, the construction is facilitated, and the using amount of a lower structure is reduced; and the transverse stiffening ribs are arranged at intervals in the pressed area of the top plate of the box girder, so that the buckling instability of the thin plate is prevented.

(2) According to the magnetic suspension UHPC box girder, the transverse ribs and the transverse partition plates of the box girder are preferably made of common concrete, and the UHPC material and the common concrete material are matched for use, so that the construction cost can be saved while the harsh running conditions of magnetic suspension traffic are met.

(3) The magnetic suspension UHPC box girder has larger fundamental frequency, smaller live load deformation and larger fundamental frequency, and can better meet the fundamental frequency requirement of the magnetic suspension girder.

(4) The cross section of the magnetic suspension UHPC box girder is smaller and is about 70-80% of that of common concrete, the beam part structure is lighter due to the smaller cross section, the lower foundation consumption is saved, the compressive strength of the UHPC material can reach about 100MPa, the tensile strength can reach about 10MPa and is far higher than that of the common concrete, the cross section of the magnetic suspension UHPC box girder is smaller, the girder is lighter, and meanwhile, a large amount of prestressed reinforcements can be arranged less.

(5) The magnetic suspension UHPC box girder has the advantages that the self-shrinkage of a UHPC material after curing is basically 0, the creep coefficient is smaller, and the magnetic suspension UHPC box girder is applied to high-speed magnetic suspension, so that the post-construction shrinkage and creep of the UHPC box girder are very small, the problem of shrinkage and creep of common concrete is effectively solved, the problem of later-stage deformation of a large-span bridge is solved, and the severe requirements of high-speed magnetic suspension on deformation can be met.

(6) According to the magnetic suspension UHPC box girder, the heat conductivity coefficient of a UHPC material is higher than that of common concrete, meanwhile, the top plate of the UHPC box girder is thinner, the local temperature difference inside and outside the box is smaller than that of the common concrete, and the temperature deformation is smaller.

Drawings

FIG. 1 is a schematic diagram of a general cross-section of a magnetically levitated UHPC box beam of an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a beam cross-rib of a magnetic levitation UHPC box of an embodiment of the invention;

FIG. 3 is a schematic cross-sectional view of a beam diaphragm of a magnetic suspension UHPC box according to an embodiment of the invention;

in all the figures, the same reference numerals denote the same features, in particular: 1-box girder top plate, 2-box girder bottom plate, 3-box girder web plate, 4-cantilever plate, 5-rail bearing beam, 6-box girder transverse rib and 7-transverse clapboard.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

The UHPC box girder provided by the invention is suitable for a high-speed magnetic levitation large-span bridge, and has the advantages of high rigidity, light structure, small later-stage deformation and convenience in construction. Fig. 1 to fig. 3 are schematic diagrams of a magnetic suspension UHPC box girder of an embodiment of the present invention in a general cross section, a cross section at a transverse rib, and a cross section at a transverse diaphragm, respectively. As shown in the figure, the magnetic suspension UHPC box girder comprises a box girder top plate 1, a box girder bottom plate 2 and a box girder web plate 3, wherein as shown in the common section of the box girder in figure 1, the box girder web plate 3 is arranged between the UHPC box girder top plate 1 and the box girder bottom plate 2, and the two transverse sides of the box girder top plate 1 extend out to form cantilever plates 4; as shown in the cross section of the cross rib of fig. 2, a box girder cross rib 6 is also arranged between the upper parts of the box girder webs 3; a diaphragm plate 7 is further arranged between web plates of the UHPC box girder, as shown in the cross section of the diaphragm plate in fig. 3, the outer part of the diaphragm plate 7 is connected with the inner cross section of the box girder to form a whole, and the arrangement position of the diaphragm plate 7 corresponds to the position of a bridge support.

The top of a box girder top plate 1 of the UHPC box girder is transversely provided with two rail bearing girders 5 according to the central line position of a double-line, and the two rail bearing girders are used as running rails of a magnetic suspension train to support the running of the magnetic suspension train; the UHPC box girder of the invention can adopt a single-box single-chamber section or a single-box double-chamber section, the section of the box girder can adopt a rectangular section (a straight web plate) or an inverted trapezoidal section (an inclined web plate). The UHPC box girder can be applied to conventional standard span simply supported girders, continuous girders, simply supported and then continuous girders, and also can be applied to large span continuous girders.

The beam height of the UHPC box girder and the plate thicknesses of a top plate, a bottom plate and a web plate are determined by calculation according to structural stress, structural requirements and a deformation control standard; wherein the beam height is determined according to the running speed of the magnetic-levitation train; the width of the top plate mainly depends on the line spacing between the two lines of the magnetic levitation, for example, the high-speed magnetic levitation at the speed of 600km/h is taken as an example, the line spacing is 5.6m, the spacing between the tops of the two webs is preferably 5-6m, the webs support the rail bearing beam, the stress performance is better, the widths of the two sides of the top plate (the width of the cantilever plate 4) are respectively 1-1.5m, namely the width of the top plate 1 of the box girder is preferably 7-9 m. For a straight web type box girder, the width of the box girder bottom plate 2 is the same as the interval between the box girder webs 3.

The thickness of the box girder top plate 1 is preferably 0.15-0.25m according to the stress requirement, and is not easy to be less than 0.15 m; the thickness of the box girder bottom plate 2 is preferably 0.2-0.3m according to the stress requirement, and is not easy to be less than 0.2 m. Because of the reduction of the thickness of the box girder, in order to prevent the buckling instability of the thin plate in the pressed area of the box girder top plate, transverse stiffening ribs (box girder transverse ribs 6) are arranged at intervals, the top of each box girder transverse rib 6 is fixedly connected with the box girder top plate 1, the transverse two ends of each box girder transverse rib are respectively fixedly connected with the inner sides of box girder web plates 3, transverse partition plates 7 are arranged at the supports, each transverse partition plate 7 is transversely fixedly connected with the inner side of each box girder web plate 3, the top of each transverse partition plate is fixedly connected with the inner side of the box girder top plate 1; the box girder transverse ribs 6 are preferably arranged at intervals of 2m, that is, the distance between two adjacent box girder transverse ribs 6 is preferably 2m, the vertical height of the box girder transverse ribs 6 is preferably 1.5-2.5m, the longitudinal length is preferably 0.2-0.4m, and the box girder transverse ribs 6 are matched with the shapes or angles of two inner sides of the box girder web transversely and can be adjusted according to the change of the web. Adopt box girder rib 6 and 7 interval collocation settings of cross slab to with the whole atress structure of box girder web consolidation position, can further promote whole rigidity and stability after the reduction of box girder thickness.

In the magnetic suspension UHPC box girder, a box girder top plate 1, a box girder bottom plate 2 and a box girder web plate 3 are made of UHPC materials, the magnetic suspension UHPC box girder can be constructed in a segmental prefabrication and assembly mode, also can be constructed in a cast-in-place mode, and when the segmental prefabrication and assembly mode is adopted, the splicing seam between two adjacent sections of UHPC box girders is preferably made of an early-strength UHPC material;

the early-strength UHPC material preferably comprises the following components of silica fume, limestone powder, cement, river sand, mixing water, a water reducing agent and steel fibers, wherein the addition ratio of the cement to the silica fume to the limestone powder to the river sand to the mixing water to the water reducing agent is (0.7-1.0): (0.1-0.2): (0.1-0.2): (0.8-1.1): (0.15-0.20): (0.02-0.05), additionally adding steel fibers, wherein the weight of the early-strength UHPC of each spliced seam is about 2300kg, and the weight of the steel fibers is 150-200 kg; the UHPC has high early strength, the compressive strength of 60MPa is achieved within 24 hours, the later strength is continuously increased, and the strength can reach more than 120MPa within 28 days; and early loading does not result in a strength collapse phenomenon.

Further preferably, the box girder transverse ribs 6 and the transverse clapboards 7 are preferably made of common concrete, and the UHPC material and the common concrete material are matched for use, so that the construction cost can be saved while the harsh running conditions of magnetic suspension traffic are met.

The UHPC box girder suitable for magnetic suspension can be applied to a large-span bridge, meets the requirement of later-stage deformation, improves the rigidity, reduces the square amount of a cross section, is light and attractive in structure, is convenient to construct and reduces the using amount of a lower structure; the prestress configuration is less, and the construction is more convenient.

Compared with the prior art, the UHPC box girder has the following advantages that:

the compressive strength, the tensile strength and the like of the UHPC box girder adopted by the invention are obviously higher than those of common concrete, the square amount of the section of the UHPC box girder is smaller and is about 70-80 percent of that of the common concrete, the beam part structure is lighter due to the smaller square amount of the section, the consumption of the foundation of the lower part is saved, the compressive strength of the UHPC material can reach about 100MPa, the tensile strength can reach about 10MPa and is far higher than that of the common concrete, the section of the UHPC box girder is smaller, the girder is lighter, and meanwhile, the configuration of a large amount of prestressed reinforcements can be reduced.

Because the UHPC elastic modulus is 1.2 times of that of common concrete, the elastic modulus/mass ratio is larger, the UHPC elastic modulus has higher rigidity under the same beam height, and the deformation requirement of high-speed magnetic levitation on the structure can be better met; meanwhile, the UHPC box girder has larger fundamental frequency, smaller live load deformation and larger fundamental frequency, and can better meet the fundamental frequency requirement of the magnetic floating girder. Compared with a steel structure, the later maintenance workload is greatly reduced, and compared with concrete, the corrosion resistance is stronger. The UHPC material has the self-shrinkage of 0 basically after curing and smaller creep coefficient, is applied to high-speed magnetic suspension, ensures that the UHPC box girder has very small post-construction shrinkage and creep, effectively solves the difficult problem of shrinkage and creep of common concrete, solves the problem of later deformation of a large-span bridge, and can meet the severe requirement of high-speed magnetic suspension on deformation. The UHPC material has higher heat conductivity coefficient than common concrete, and simultaneously, the UHPC box girder top plate is thinner, the local temperature difference inside and outside the box is smaller than the section of the common concrete, and the temperature deformation is smaller. The ultrahigh durability of the UHPC greatly saves the maintenance workload in the later period. The advantages enable the UHPC box girder to have stronger spanning capability than the common concrete girder, can be applied to large-span (60m and above) magnetic suspension bridges, and meet the severe deformation index.

To better illustrate the advantages of the invention in the application of the magnetic suspension UHPC box girder, taking a 60m high-speed magnetic suspension bridge as an example, the span of the bridge is (40+60+40) m, the side spans at two ends of the main span are 40m, and equal-height UHPC continuous box girders are adopted, the girder height of the box girder depends on the requirements of deformation and fundamental frequency; the deformation requirements comprise deformation requirements under live load and deformation requirements under temperature, the property parameters of the bridge are calculated when the height of the bridge is 5m and 4.4m respectively, the width of the top of the bridge is set to be 7.7m, the width of the bottom of the bridge is set to be 5.7m, the thickness of a bottom plate and a web plate is set to be 0.25m, the thickness of a top plate is set to be 0.15m, and a hogging moment area is thickened to be 0.25 m; a transverse stiffening rib is arranged at the interval of 2m and is 2m high. The top plate, the bottom plate, the web plate and the splicing seam of the box girder are made of UHPC materials, and the stiffening ribs and the transverse partition plate are made of common concrete.

The results for a 5m beam height are as follows:

the results for a 4.4m beam height are as follows:

the results show that: for UHPC continuous beams of 40+60+40m, the 4.4m and 5.0m beams can meet the requirements of magnetic suspension traffic on high stress, static and live load rigidity, temperature deformation, shrinkage creep and the like.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.