Patent Application
20250137207
This application claims priority to Chinese Patent Application Number 2023113880776, filed Oct. 25, 2023, the disclosure of which is incorporated herein by reference in its entirety.
The present disclosure belongs to the technical field of arch bridge structures, and particularly relates to a steel-concrete combined skewback structure and a construction method thereof.
Existing common arch bridges mainly structurally include skewbacks, arch rings, and main bridge bodies. The arch bridges may further be divided into deck bridges, midheight deck bridges, and through bridges according to relative height differences between the arch rings and the main bridge bodies.
On the other hand, auxiliary structures of the arch bridges further include arch ribs and bearing platforms. The arch ribs may reinforce the arch rings, that is, as frameworks of the arch rings. When soil conditions on construction sites of the arch bridges are relatively poor, the skewbacks cannot be directly arranged on primary soil layers, and otherwise harmful phenomena of instable and insufficient supporting effects of the skewbacks are likely to occur. At this moment, the bearing platforms may be built on the relatively weak primary soil layers firstly, followed by construction of the skewbacks on the bearing platforms.
Correspondingly, the skewbacks and the arch ribs may also be collectively referred to as skewbacks or skewback structures during actual construction of the arch bridges.
The most fundamental advantage of existing relatively advanced skewback structures, namely steel-concrete combined skewbacks is to be capable of combining tensile characteristics of steel structures and compression-resistant characteristics of concrete.
For example, A Chinese invention patent No. CN114250690A published on Mar. 29, 2022 has disclosed a steel-concrete combined skewback suitable for a concrete-filled steel tube arch bridge, structurally including a core steel skewback. Concrete is poured into the core steel skewback, and concrete is poured on an outer side of the core steel skewback; the core steel skewback includes a top plate and a bottom plate which are oppositely arranged, a plurality of webs are arranged between the top plate and the bottom plate, and two sides of the webs are blocked by side vertical plates and bearing plates; and the bearing plates are obliquely arranged, and force transmission plates are fixedly arranged on inner sides of the bearing plates.
The steel-concrete combined skewback in this invention patent mainly has the advantages that 1. advantageous performance of steel plates and concrete is fully exerted; 2. the skewback is filled with the concrete, so that the stability of the skewback can be improved, and meanwhile, the concrete is pressed in three directions under the action of hooping of the skewback on the concrete, so that the steel-concrete combined skewback has higher compressive strength and deformation resistance; and 3. the quantity, sizes and dip angles of the bearing plates of the skewback in a transverse bridge direction can be freely adjusted according to the number and positions of concrete-filled steel tubes in arch ribs.
However, the steel-concrete combined skewback at least further has the following shortcoming, that is, the technical problem to be solved by the present disclosure during actual construction and use:
When used in cooperation with a bearing platform, the steel-concrete combined skewback can only be vertically supported by the bearing platform simply, but cannot be combined with the bearing platform, resulting in inability to transmit transverse thrust to the bearing platform, which in turn hardly improves the structural strength of the whole arch bridge.
Therefore, in conclusion, there is an urgent need for a novel steel-concrete skewback that can be connected with an existing bearing platform at high strength.
The present disclosure provides a steel-concrete combined skewback structure. By arranging arch rib tubes, concrete sections in a main chord pipe, concrete blocks in a skewback, fixing steel tubes, a transverse diaphragm unit, and a vertical diaphragm unit, the steel-concrete combined skewback structure can achieve the following objectives that 1. the skewback structure can be fully connected with a bearing platform, so as to ensure a stable foundation for transverse and vertical support force of the skewback structure; and 2. the fixing steel tubes are fully filled with concrete, so as to further improve the structural strength of the above connection.
In addition, the present disclosure further provides a construction method of the above steel-concrete combined skewback structure. The construction method sequentially includes the steps: positioning fixing steel tubes, positioning a steel structure box unit, mounting arch rib tubes, pouring concrete, and performing concrete vibration and compaction curing. Finally, the skewback structure itself and its mounting manner both have sufficient structural stability.
A technical solution adopted by the present disclosure to solve the above problems is as follows: A steel-concrete combined skewback structure, includes arch rib tubes, concrete sections in a main chord pipe, and concrete blocks in a skewback, and further includes a steel structure box unit internally provided with the concrete blocks in the skewback and used for allowing the arc rib tubes to be inserted therein, fixing steel tubes inserted into the steel structure box unit and used for connecting a bearing platform, a transverse diaphragm unit arranged in the steel structure box unit and used for sleeving the fixing steel tubes, and a vertical diaphragm unit arranged on the transverse diaphragm unit and used for filling the fixing steel tubes with concrete by sleeving the arch rib tubes.
In a further preferred technical solution, the steel structure box unit includes a bottom plate, lower vertical plates, lower inclined plates, upper vertical plates, upper inclined plates, a top plate, and two sealed webs arranged on the bottom plate, wherein the lower vertical plates, the lower inclined plates, the upper vertical plates, the upper inclined plates, and the top plate are sequentially arranged on the bottom plate from bottom to top.
In a further preferred technical solution, the steel structure box unit further includes fixing holes formed in the bottom plate and used for allowing the fixing steel tubes to be inserted therein, mounting holes formed in the lower inclined plates and used for allowing the arc rib tubes to be inserted therein and adding concrete into the fixing steel tubes, and communicating holes formed in the upper inclined plates and used for pouring the concrete blocks in the skewback.
In a further preferred technical solution, the steel structure box unit further includes a pouring hole formed in the top plate.
In a further preferred technical solution, the transverse diaphragm unit includes a lower cross plate arranged on the two lower vertical plates, an upper cross plate arranged on the two upper vertical plates, reinforcing holes formed in the lower cross plate and used for allowing the fixing steel tubes to be inserted therein, and concrete falling holes formed in the lower cross plate and the upper cross plate.
In a further preferred technical solution, the vertical diaphragm unit includes lower vertical plates arranged on the bottom plate and the lower cross plate, middle vertical plates arranged on the lower cross plate and the upper cross plate, and upper vertical plates arranged on the upper cross plate and the top plate.
In a further preferred technical solution, the vertical diaphragm unit further includes positioning vertical plates arranged on an upper surface of the lower cross plate and used for blocking insertion ends of the arch rib tubes, and vertical hole plates for limiting arranged on the upper surface of the lower cross plate and used for sleeving the arch rib tubes.
In a further preferred technical solution, stiffening ribs are respectively arranged on the lower cross plate, the upper cross plate, the lower vertical plates, the middle vertical plates, the upper vertical plates, the positioning vertical plates, and the vertical hole plates for limiting.
A construction method of a steel-concrete combined skewback structure, sequentially includes the following steps:
In a further preferred technical solution, in S4 of pouring concrete, the concrete is also added to the steel structure box unit.
In the drawings, the meanings of reference signs are as follows:
The following descriptions are only preferred embodiments of the present disclosure, but are not construed as limiting the scope of the present disclosure.
As shown in
In this embodiment, the arch rib tubes 11 are main frameworks of arch rings, the “steel-concrete combination” characteristic of the skewback structure is reflected both in the arch rib tubes 11 and the steel structure box unit 1, where the concrete sections 12 in the main chord pipe are formed by pouring concrete into the arch rib tubes 11, and the concrete blocks 13 in the skewback are formed by pouring the concrete into the steel structure box unit 1.
Then, the steel structure box unit 1 is closed, which aims at hooping and covering a concrete structure, so as to finally improve the structural strength and structural long-term stability of the steel-concrete combined structure.
In addition, the steel structure box unit 1 is prefabricated in a factory and then transported to a construction site, where concrete is poured finally. When the steel structure box unit 1 is prefabricated, the transverse diaphragm unit 3 and the vertical diaphragm unit 4 are also fully welded and fixed into the steel structure box unit. While the arch rib tubes 11 are welded to the steel structure box unit 1 on the construction site.
On the other hand, before the steel structure box unit 1 is lowered by a crane, the fixing steel tubes 2 have been kept in a stable vertical state due to the sufficient curing effect of the bearing platform a. However, at this moment, only lower portions of the fixing steel tubes 2 are filled with the concrete, and a height of the concrete inside the fixing steel tubes is a height of an upper surface of the bearing platform.
Therefore, upper concrete sections in the fixing steel tubes 2, the concrete blocks 13 in the skewback and the concrete sections 12 in the main chord pipe need to be obtained together by continuously adding and pouring the concrete. However, if the upper concrete sections in the fixing steel tubes 2 are obtained in a manner that the concrete at the concrete blocks 13 in the skewback overflows inward and falls in occasionally, time needed for filling is long, and the following situation is likely to happen:
Due to the hollow structure, the strength of the fixing steel tubes 2, connecting structures of the steel structure box unit 1 and the bearing platform a, as well as the steel structure box unit 1 itself will be finally reduced, which need to be prevented.
Therefore, finally, a part of the arch rib tubes 11 are inserted into the steel structure box unit 1, the concrete can be ejected massively, rapidly and centrally to be used for fully filling the fixing steel tubes 2 and then can be slowly accumulated to form the concrete blocks 13 in the skewback. The purpose of the specific structure and the specific manner for adding the concrete is to prevent the hollow sections of the fixing steel tubes 2.
The steel structure box unit 1 includes a bottom plate 101, lower vertical plates 102, lower inclined plates 103, upper vertical plates 104, upper inclined plates 105, a top plate 106, and two sealed webs 107 arranged on the bottom plate 101, wherein the lower vertical plates, the lower inclined plates, the upper vertical plates, the upper inclined plates, and the top plate are sequentially arranged on the bottom plate 101 from bottom to top.
In this embodiment, the steel structure box unit 1 is of an all-steel structure, and all gaps among the above twelve plates are fully welded to ensure that the concrete structure is fully limited and protected in a steel structure for the reason that the steel structure is not prone to weathering and peeling compared with the concrete structure.
Only the two sealed webs 107 in the above twelve plates are in composite shapes, the other plates are all rectangular, and specific shapes of the sealed webs 107 vary as smaller trapezoids, smaller rectangles, larger trapezoids and larger rectangles from top to bottom.
The steel structure box unit 1 further includes fixing holes 108 formed in the bottom plate 101 and used for allowing the fixing steel tubes 2 to be inserted therein, mounting holes 109 formed in the lower inclined plates 103 and used for allowing the arc rib tubes 11 to be inserted therein and adding concrete into the fixing steel tubes 2, and communicating holes 110 formed in the upper inclined plates 105 and used for pouring the concrete blocks 13 in the skewback.
In this embodiment, the single steel structure box unit 1 corresponds to four rows of arch rib tubes 11, so that a row of open holes needs to be formed in each of the two lower inclined plates 103 and the two upper inclined plates 105.
In addition, connecting rods 6 are in cross shapes or X shapes and are steel rods that are welded integrally, which are formed by welding the two arch rib tubes 11 on upper and lower portions on the same side together, thereby improving the integrity of the skewback structure.
As for the two rows of arch rib tubes 11 on a lower portion, the concrete is priorly added into the fixing steel tubes 2 pertinently, while the arch rib tubes 11 on an upper portion do not need this. Therefore, dimensions of the mounting holes 109 are greater than those of the communicating holes 110. The mounting holes at least need to penetrate through the arch rib tubes 11, while the communicating holes can allow falling concrete slurry to be added therein.
Finally, the fixing steel tubes 2 that have been fixed priorly are inserted into the fixing holes 108, thereby ensuring that a lowering position of the steel structure box unit 1 is a preset position.
The steel structure box unit 1 further includes a pouring hole 111 formed in the top plate 106.
In this embodiment, if all the concrete needed for the skewback is only added into the arch rib tubes 11, long time consumed may exist. Therefore, the pouring hole 111 is formed, so as to further shorten time needed for adding the concrete on the premise of fully filling the fixing steel tubes 2 with the concrete similarly.
On the other hand, openings for concrete adding may be formed in the arch rib tubes 11, followed by welding of filling steel plates. Alternately, the concrete may be directly added to exposed ends of the arch rib tubes 11 with relatively small lengths, and subsequent complete arch rib steel tube structures may be obtained by sleeving the arch rib tubes 11 with new and arc-shaped steel tubes.
The transverse diaphragm unit 3 includes a lower cross plate 301 arranged on the two lower vertical plates 102, an upper cross plate 302 arranged on the two upper vertical plates 104, reinforcing holes 303 formed in the lower cross plate 301 and used for allowing the fixing steel tubes 2 to be inserted therein, and concrete falling holes 304 formed in the lower cross plate 301 and the upper cross plate 302.
In this embodiment, the transverse diaphragm unit 3 and the vertical diaphragm unit 4 are also made of steel plates, both of which have nearly the same effects, mainly including the following two:
The reinforcing holes 303 vertically align with the fixing holes 108, so as to achieve reinforced connection between the steel structure box unit 1 and the fixing steel tubes 2.
In addition, four sides of each of the lower cross plate 301 and the upper cross plate 302 are fully welded, so that positions in the steel structure box unit 1 and below the upper cross plate 302 are completely unable to be filled with the concrete if there are no concrete falling holes 304, which is the purpose of forming the concrete falling holes 304.
The vertical diaphragm unit 4 includes lower vertical plates 401 arranged on the bottom plate 101 and the lower cross plate 301, middle vertical plates 402 arranged on the lower cross plate 301 and the upper cross plate 302, and upper vertical plates 403 arranged on the upper cross plate 302 and the top plate 106.
In this embodiment, the lower vertical plates 401, the middle vertical plates 402 and the upper vertical plates 403 are all rectangular, however, respective lengths and widths should be set as required, so as to ensure the sufficient vertical supporting effect.
Specifically, the two upper vertical plates 403, the four middle vertical plates 402 and the six to ten lower vertical plates 401 are arranged.
Finally, left and right vertical sides of the above three kinds of vertical plates cannot be welded and sealed, and gaps allowing the concrete to pass should be reserved between these vertical sides and the two sealed webs 107. In other words, widths of the above three kinds of vertical plates are less than widths of the upper and lower cross plates.
The vertical diaphragm unit 4 further includes positioning vertical plates 404 arranged on an upper surface of the lower cross plate 301 and used for blocking insertion ends of the arch rib tubes 11, and vertical hole plates 405 for limiting arranged on the upper surface of the lower cross plate 301 and used for sleeving the arch rib tubes 11.
In this embodiment, the positioning vertical plates 404 are terminal indicating positions of insertion actions of the arch rib tubes 11, and open holes in the vertical hole plates 405 for limiting align with the mounting holes 109, so as to finally ensure that inner tube orifices of the arch rib tubes 11 close to lower portions are close to upper tube orifices of the fixing steel tubes 2 as much as possible.
Due to such positional and structural relationship, it can be ensured that the fixing steel tubes 2 are fully filled with the concrete, thereby achieving higher structural strength of the fixing steel tubes themselves.
The positioning vertical plates 404 are rectangular, the vertical hole plates 405 for limiting are configured as a style that inclined holes are formed in rectangular plates, or straight holes are formed in upper portions of two-section type bent plates, and the latter is shown in
Stiffening ribs 5 are arranged on the lower cross plate 301, the upper cross plate 302, the lower vertical plates 401, the middle vertical plates 402, the upper vertical plates 403, the positioning vertical plates 404, and the vertical hole plates 405 for limiting.
In this embodiment, the stiffening ribs 5 are used for reinforcing the self-stability of the above cross plate and vertical plate structures and upgrading “plate structures” into “frame structures”, and therefore the above cross plates and vertical plates are not prone to bending deformation.
The stiffening ribs 5 may be arranged as transverse, vertical or inclined, which also has the effect of the shear keys in the concrete blocks 13 in the skewback.
A construction method of a steel-concrete combined skewback structure, sequentially includes the following steps:
In this embodiment, after the fixing steel tubes 2 have been fully filled with the concrete, the arch rib tubes 11 on lower portions that have been inserted already may be pulled out properly, at a result, concrete shear keys may be formed at the open holes in the vertical hole plates 405, for limiting and similarly the concrete and the vertical diaphragm unit 4 can be reinforced.
In S4 of pouring concrete, the concrete is also added to the steel structure box unit 1.
In this embodiment, the concrete adding action at the pouring hole 111 has neither harm nor benefit to the requirements of priorly filling the fixing steel tubes 2 with the concrete. The pouring hole 111 is mainly used for rapidly and fully filling up the whole concrete blocks 13 in the skewback.
The implementations of the present disclosure are described in detail above with reference to the drawings, however, the present disclosure is not limited to these. Those of ordinary skill in the art can also make various modifications within their knowledge range without departing from the purpose of the present disclosure. These modifications are not inventive, and are protected by patent laws as long as they fall within the scope of the claims of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023113880776 | Oct 2023 | CN | national |
