Pipe construction and bridge for ensuring the compaction of the concrete cast in pipe

Abstract

The application relates to the technical field of bridge engineering, and provides a pipeline structure for guaranteeing the pouring density of in-pipe concrete and a bridge, wherein the pipeline structure for guaranteeing the pouring density of in-pipe concrete comprises a main pipeline; one end of the main pipeline is provided with a pouring structure, and the other end is provided with a spouting structure; concrete can enter the inside of the main pipeline from the pouring structure and flow out of the main pipeline from the spouting structure; the upper surface of the main pipeline is further provided with gas spouting through holes; the gas spouting through holes are distributed at intervals along the length direction of the main pipeline, and the gas spouting through holes are used for discharging the gas in the inside of the main pipeline. The application can solve the problems that the pouring density of concrete is difficult to be guaranteed when the concrete pouring is carried out on the steel pipe concrete combined component in a high-altitude low-pressure environment, and the problems that the concrete pipe is blocked, and the concrete is debonded and empty from the main pipeline.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge engineering, and particularly relates to a pipeline structure for guaranteeing the pouring density of in-pipe concrete and a bridge. BACKGROUND

[0002] The plateau mountainous area highway construction project is located in a high-elevation area with a low average annual temperature, an atmospheric pressure value of 550-650 mmHg (60 KPa), an oxygen content of about 206 g / m3, an average high temperature of 11℃, and an average low temperature of -4℃. The longest winter season lasts more than 310 days. In the Chengdu plain area, the atmospheric pressure value is about 718 mmHg (95.8 KPa), the oxygen content is about 260 g / m3, the average high temperature is 22℃, and the average low temperature is 14℃. Compared with the Chengdu plain area, the plateau mountainous area highway construction has the following characteristics: a long winter season, a short effective construction time throughout the year, a large construction difficulty and a difficult quality control due to the extremely low temperature and repeated temperature difference during the outdoor construction, a large labor intensity of workers due to the thin air and low oxygen content, and low concrete air content and poor working performance.

[0003] The standard span bridge in the plateau mountainous area generally adopts a steel pipe concrete truss girder bridge, and 80% of the overall workload is completed in a factory, so that the amount of on-site work is small, the quality is controllable, and the construction is fast. Meanwhile, in the plateau high-elevation area, sand and stone materials are scarce, the ecological environment is sensitive and fragile, and the environmental protection requirement is high. The steel pipe concrete bridge has a small amount of concrete, saves sand and stone materials, the steel can be recycled and remelted to build a new bridge after the design service life, is a typical low-carbon and environmentally friendly bridge, and therefore, the bridge type becomes the best choice for the standard span bridge in the plateau mountainous area.

[0004] One of the prerequisites for ensuring the bending and tensile bearing capacity of the steel pipe concrete combined component used as the bending and tensile stress structure of the lower chord pipe of the steel pipe concrete truss girder bridge is to ensure the pouring density of the in-pipe concrete, to form a stable combined structure, and to enable the two materials to bear the load cooperatively. Meanwhile, the web pipe of the steel pipe concrete truss girder bridge is directly supported on the lower chord pipe through a penetrating welding joint, the out-of-plane stress of the lower chord pipe is large, the pouring density of the in-pipe concrete of the lower chord pipe is an important guarantee for meeting the overall rigidity of the structure and the local rigidity of the joint, so as to ensure that the local bulging and depression and other out-of-plane deformations do not occur under the action of the large concentrated force of the web pipe. The higher the pouring density of the in-pipe concrete of the lower chord pipe, especially the in-pipe top surface concrete, the greater the local rigidity of the joint, the smaller the amplitude of the hot spot stress of the joint, and the higher the fatigue strength of the joint of the pouring dense lower chord pipe, so that the overall fatigue life of the bridge structure is improved.

[0005] However, when the bridge site is located in a high-altitude and low-pressure environment, the work performance of the concrete will be lost, the pumpability will be reduced, and the length of the main pipe is often long. In the actual construction process, the concrete often cannot be filled and compacted in the main pipe, and in severe cases, the concrete and the main pipe may even be debonded and empty. And the concrete pouring is prone to pipe blockage. SUMMARY

[0006] The purpose of the present application is to solve the problem of difficulty in ensuring the compaction degree of concrete pouring in a high-altitude and low-pressure environment, and to provide a pipe structure and a bridge for ensuring the compaction degree of concrete pouring in a pipe.

[0007] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0008] A pipe structure for ensuring the compaction degree of concrete pouring in a pipe, comprising a main pipe; the main pipe is provided with a pouring structure at one end and a spouting structure at the other end, and the concrete can enter the inside of the main pipe from the pouring structure and flow out of the main pipe from the spouting structure; the upper surface of the main pipe is also provided with a gas spouting hole; the gas spouting hole is distributed along the length direction of the main pipe, and the gas spouting hole is used to discharge the gas inside the main pipe.

[0009] The specific design of the main pipe refers to the steel pipe in the existing steel pipe concrete composite member; the main pipe includes but is not limited to a circular cross-section steel pipe, a rectangular cross-section steel pipe, and a steel box structure of a steel box concrete cover beam; the pouring structure can be various forms capable of pouring concrete into the main pipe, such as a pouring hole or a pouring pipe; the spouting structure can be various forms capable of making concrete flow out of the main pipe, such as a spouting hole or a spouting pipe; the pouring structure and the spouting structure can be provided with one or more according to the flow of the concrete.

[0010] The distribution interval of the gas spouting hole is determined according to the specific cross-sectional area of the main pipe, the loss of concrete air content, and the main pipe structure.

[0011] The inventor of the present application found that when pouring concrete into the steel pipe of the steel pipe concrete composite member in a high-altitude and low-pressure environment, the compaction degree of the concrete is difficult to guarantee and the pipe is prone to blockage, which is mainly due to the poor stability of the internal bubbles of the concrete, the rapid loss of air content, the large loss of work performance, and the poor pumpability in the high-altitude and low-pressure environment, thereby easily causing pipe blockage; at the same time, due to the excessive length of the main pipe, the pumping pressure and the low-pressure environment cause the bubbles to break and escape, and it is difficult to exhaust after the bubbles break and escape, especially the large air sacs are easily formed on the top of the main pipe, thereby affecting the close combination of the steel pipe and the concrete in the pipe, and causing the debonding and emptying phenomenon;

[0012] Meanwhile, the inventors conduct experiments on the pouring process of concrete in the main pipeline under high-altitude low-pressure environment. During the experiment, the concrete is collected from the pouring structure and the spouting structure respectively, and the air content of the concrete is tested. It is found that the air content of the concrete collected from the spouting structure is less than 60% of the pouring structure. It is judged that the gas is removed during the transportation of the concrete and before the setting. The gas removal hole is needed to be arranged in the transportation path to remove the gas smoothly. According to the engineering practice experience, the path of the concrete in the pipeline is piston type. Therefore, it is considered that the air in the main pipeline is squeezed forward by the concrete. Correspondingly, the gas removal hole is arranged on the upper surface of the main pipeline and is distributed along the length direction of the main pipeline. The position of the gas removal hole is close to the atmosphere bag. The length of the gas removal path is reduced. The gas in the main pipeline is removed efficiently. The pouring density of the concrete in the main pipeline is ensured. The structure of the scheme is simple. The manufacturing cost is low. The scheme can be obtained by directly drilling holes on the existing main pipeline. The scheme has good popularization prospect.

[0013] As a preferred scheme of the present application, the distribution interval of the gas removal hole along the length direction of the main pipeline is d, and d satisfies the following formula:

[0014]

[0015] In the formula, L 主 is the length of the main pipeline; S 主 is the cross-sectional area of the main pipeline; V 砼 is the flow rate of the concrete; V 气 is the flow rate of the gas; Δ 气 is the air content loss rate of the concrete; S 冒 is the cross-sectional area of the gas removal hole.

[0016] The scheme gives an empirical formula of the distribution interval of the gas removal hole according to the experimental data. The formula is used to guide the arrangement of the gas removal hole. The situation that the exhaust capacity cannot meet the exhaust demand due to the too small distribution density of the gas removal hole or the situation that the exhaust capacity is too large due to the too large distribution density of the gas removal hole, which causes negative impact on the strength of the main pipeline, can be avoided.

[0017] As a preferred scheme of the present application, the gas removal hole is circular. The diameter of the gas removal hole is D1, and 5mm≤D1≤10mm.

[0018] The scheme gives a recommended value of the diameter of the gas removal hole according to the experimental data.

[0019] As a preferred scheme of the present application, the spouting structure is a tubular structure connected to the main pipeline. The end of the spouting structure away from the main pipeline is located outside the projection of the main pipeline on the horizontal plane.

[0020] The grouting structure can be made in various forms so that its end extends beyond the projection of the main pipe onto the horizontal plane, for example, by using a grouting structure with a bend, or by making the grouting structure deviate from one side of the main pipe along the transverse direction.

[0021] This solution uses a tubular grout outlet structure, with the end of the grout outlet structure extending beyond the projection of the main pipe on the horizontal plane. This prevents concrete from flowing out of the grout outlet structure and falling onto the main pipe, thus avoiding contamination of the main pipe. It also makes it easier to collect the outflowing concrete from the outlet of the grout outlet structure for subsequent use or centralized treatment.

[0022] As a preferred embodiment of the present invention, the axis of the slurry discharge structure has an angle α with the vertical plane passing through the axis of the main pipe; α > 0°.

[0023] The size of the included angle α depends on the specific dimensions of the grouting structure, the main pipe, and the relative positions of the grouting structure and the main pipe. As long as the end of the grouting structure extends beyond the projection of the main pipe onto the horizontal plane, it is acceptable.

[0024] This solution recommends one of the structural forms that allows the end of the grout outlet structure to extend beyond the projection of the main pipe on the horizontal plane. Using this structural form can reduce the shape complexity of the grout outlet structure, for example, by directly using a straight pipe, thereby reducing the manufacturing cost and installation difficulty of the grout outlet structure, and at the same time, it is also conducive to making the return of concrete smoother.

[0025] As a preferred embodiment of the present invention, the grouting structure is a tubular structure connected to the main pipeline; the inner diameter of the grouting structure is D2, the diameter of the concrete coarse aggregate is D3, and D2≥5*D3.

[0026] This scheme recommends a range of values ​​for the inner diameter of the tubular grout outlet structure, which can ensure that concrete flows out smoothly from the grout outlet structure and avoids concrete blockage inside the grout outlet structure.

[0027] As a preferred embodiment of the present invention, the slurry venting structure is a tubular structure connected to the main pipe; the end of the slurry venting structure away from the main pipe is higher than the top of the main pipe.

[0028] The distance between the end of the grout overflow structure and the top of the main pipe is determined according to the specific concrete return requirements.

[0029] This plan recommends that the end of the grout overflow structure be higher than the top of the main pipe. This allows some concrete to flow back into the main pipe after the venting is completed, thereby further ensuring the compactness of the concrete pouring in the main pipe.

[0030] As a preferred embodiment of the present invention, a reinforcing structure is further provided inside the main pipe; at least one of the air venting holes is provided at the connection between the main pipe and the reinforcing structure.

[0031] The stiffening structure can take various forms, such as a stiffening ring with its axis parallel to the main pipe or a stiffening rib plate set along the length of the main pipe; one or more vent holes can be set at each stiffening structure according to the actual exhaust requirements.

[0032] This solution recommends that vent holes be installed at all stiffening structures to avoid dead zones in the exhaust channel caused by the stiffening structure, which could affect the exhaust performance.

[0033] A steel-concrete composite bridge includes a steel-concrete composite component; the steel pipe of the steel-concrete composite component adopts a pipe structure of the present invention for ensuring the compactness of the concrete pouring inside the pipe.

[0034] Steel-concrete composite components, such as steel-concrete main beams and steel-concrete crossbeams; the steel box of the steel box concrete cap beam can also adopt the pipe structure of the present invention for ensuring the compactness of the concrete pouring inside the pipe.

[0035] The steel-concrete composite bridge of this solution adopts a pipe structure of the present invention to ensure the compactness of the concrete pouring inside the pipe. Therefore, it can ensure the compactness of the concrete pouring inside the steel-concrete composite component during the concrete pouring operation, thereby ensuring that the steel pipe and concrete are subjected to stress together, and thus ensuring the overall fatigue life of the steel-concrete composite bridge.

[0036] As a preferred embodiment of the present invention, the main pipeline is filled with concrete; the concrete is self-compacting shrinkage-compensating concrete.

[0037] This plan recommends using self-compacting shrinkage-compensating concrete to fill the main pipeline, which can utilize the good fluidity of self-compacting shrinkage-compensating concrete to further ensure the compactness of the concrete filling in the main pipeline.

[0038] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0039] 1. The pipe structure of this solution, used to ensure the compactness of the concrete pouring inside the pipe, can efficiently remove air from all parts of the main pipe along its length when the main pipe is being poured with concrete, thereby ensuring the compactness of the concrete pouring inside the main pipe; moreover, this solution has a simple structure, low manufacturing cost, and can be obtained by drilling directly on the existing main pipe, and has good prospects for promotion.

[0040] 2. The steel-concrete composite bridge of this solution adopts a pipe structure of the present invention to ensure the compactness of the concrete pouring inside the pipe. Therefore, it can ensure the compactness of the concrete pouring inside the steel-concrete composite component during the concrete pouring operation, thereby ensuring that the steel pipe and concrete are subjected to stress together, and thus ensuring the overall fatigue life of the steel-concrete composite bridge. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the axial structure of a pipe structure for ensuring the compactness of concrete pouring inside the pipe, according to the present invention. Figure 1 ;

[0042] Figure 2 This is a schematic diagram of the axial structure of a pipe structure for ensuring the compactness of concrete pouring inside the pipe, according to the present invention. Figure 2 ;

[0043] Figure 3 This is a partial schematic diagram of the grout overflow structure;

[0044] Figure 4 This is a schematic diagram of the circumferential structure of a pipe structure for ensuring the compactness of concrete pouring inside the pipe, according to the present invention.

[0045] Figure 5 This is a partial cross-sectional schematic diagram of a pipe structure used to ensure the compactness of concrete pouring inside the pipe, as shown in Example 2.

[0046] Icons: 1-Main pipe; 2-Injection structure; 3-Grouting structure; 4-Gas outlet; 5-Reinforcing structure. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings.

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0049] Example 1

[0050] like Figures 1 to 5 As shown, the present invention employs a pipe structure for ensuring the compactness of concrete pouring inside the pipe, comprising a main pipe 1; a pouring structure 2 is provided at one end of the main pipe 1, and a grout outlet structure 3 is provided at the other end, allowing concrete to enter the main pipe 1 from the pouring structure 2 and flow out of the main pipe 1 from the grout outlet structure 3; an air vent 4 is also provided on the upper surface of the main pipe 1; the air vent 4 is spaced along the length of the main pipe 1, and is used to expel gas from inside the main pipe 1.

[0051] The vent holes 4 are distributed at intervals d along the length of the main pipe 1, where d satisfies the following formula:

[0052]

[0053] In the formula, L 主 The length of main pipe 1; S 主The cross-sectional area of ​​main pipeline 1; V 砼 V is the concrete flow velocity. 气 Δ represents the gas flow rate. 气 S represents the air content loss rate of concrete. 冒 The cross-sectional area of ​​the vent hole 4 is given.

[0054] Specifically, in this embodiment, the main pipe 1 is a horizontally placed circular pipe with a diameter of D. 主 = 670mm, length L 主 =30m; therefore, the cross-sectional area S of main pipe 1 主 The calculation formula is as follows:

[0055]

[0056] In this embodiment, the venting hole 4 is circular; the diameter of the venting hole 4 is D1, 5mm≤D1≤10mm; therefore, the cross-sectional area S of the venting hole 4 is... 冒 The calculation formula is as follows:

[0057]

[0058] Therefore, the specific formula for calculating the distribution spacing d is as follows:

[0059]

[0060] Specifically, in this embodiment, D1 is 10mm, V 砼 Take 0.58 m / s, V 气 Take 10 m / s, Δ 气 Take 2.5%, L 主 =30m, D 主 =670mm, so d can be calculated to be 4608mm, that is, the vent holes 4 are evenly distributed on the main pipe 1 at intervals of about 4000mm.

[0061] According to the calculation formula of d, the workability of the concrete in the main pipeline 1 needs to meet the following requirements: air content ≤ 2.5%, slump ≥ 20cm, spread 50~65cm, and V-shaped funnel passage time 10~25s. If the workability is less than this requirement, the density of the air vent 4 can be appropriately increased.

[0062] like Figures 1 to 4 As shown, the grouting structure 3 is a tubular structure connected to the main pipe 1. The end of the grouting structure 3 away from the main pipe 1 is located outside the projection of the main pipe 1 on the horizontal plane. The inner diameter of the grouting structure 3 is D2, and the diameter of the concrete coarse aggregate is D3, where D2≥5*D3.

[0063] Specifically, the grout overflow structure 3 is a straight tubular structure connected to the upper surface of the corresponding end of the main pipe 1, and as shown in the figure...Figure 3 and Figure 4 As shown, the axis of the slurry venting structure 3 has an angle α with the vertical plane passing through the axis of the main pipe 1, where α > 0°; the end of the slurry venting structure 3 away from the main pipe 1 is higher than the top of the main pipe 1, and the height difference is H; for this embodiment, 15° ≤ α ≤ 30°, 50cm ≤ H ≤ 150cm.

[0064] The grouting structure 2 is also a tubular structure connected to the main pipe 1, specifically a tubular structure connected to the end face of the corresponding end of the main pipe 1.

[0065] Example 2

[0066] Based on Example 1, a stiffening structure 5 is also provided inside the main pipe 1; at least one venting hole 4 is provided at the connection between the main pipe 1 and the stiffening structure 5.

[0067] Depending on the length of the main pipeline 1, the stiffening structure 5 should be installed at least at the mid-span. The longer the main pipeline 1, the more stiffening structures 5 need to be installed. The stiffening structures 5 can be installed at equal intervals or at varying intervals.

[0068] like Figure 5 As shown, a number of reinforcing rings are arranged at intervals inside the main pipe 1 as a reinforcing structure 5. Therefore, in addition to the venting holes 4 arranged at equal intervals along the length of the main pipe 1, this embodiment also provides an additional venting hole 4 at each reinforcing ring, thereby avoiding dead corners in the exhaust channel.

[0069] Example 3

[0070] A steel-concrete composite bridge includes steel-concrete composite members; the steel pipes of the steel-concrete composite members adopt any one of the pipe structures in Embodiment 1 or 2 to ensure the compactness of the concrete pouring inside the pipe.

[0071] The main pipeline 1 is filled with concrete; the concrete is self-compacting shrinkage-compensating concrete, and in this embodiment, C30 self-compacting shrinkage-compensating concrete is specifically used.

[0072] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pipe structure for ensuring the compactness of concrete pouring inside the pipe, comprising a main pipe (1), characterized in that, The main pipe (1) is provided with a grouting structure (2) at one end and a slurry outlet structure (3) at the other end. Concrete can enter the main pipe (1) from the grouting structure (2) and flow out of the main pipe (1) from the slurry outlet structure (3). The upper surface of the main pipe (1) is also provided with a gas outlet hole (4). The gas outlet hole (4) is distributed at intervals along the length of the main pipe (1). The gas outlet hole (4) is used to remove gas from the inside of the main pipe (1). The spacing between the venting holes (4) along the length of the main pipe (1) is: , Satisfy the following formula: In the formula, The length of the main pipe (1); The cross-sectional area of ​​the main pipeline (1); The concrete flow rate; This refers to the gas flow rate; This refers to the air loss rate of concrete. The cross-sectional area of ​​the venting through-hole (4) is; The slurry outlet structure (3) is a tubular structure connected to the main pipe (1); the end of the slurry outlet structure (3) away from the main pipe (1) is located outside the projection of the main pipe (1) on the horizontal plane; the inner diameter of the slurry outlet structure (3) is The diameter of the coarse aggregate in the concrete is , The end of the slurry structure (3) away from the main pipe (1) is higher than the top of the main pipe (1).

2. The pipe structure for ensuring the compactness of concrete pouring inside the pipe according to claim 1, characterized in that, The venting hole (4) is circular; the diameter of the venting hole (4) is D1, 5mm≤D1≤10mm.

3. A pipe structure for ensuring the compactness of concrete pouring inside the pipe according to any one of claims 1, characterized in that, The axis of the slurry structure (3) has an angle α with the vertical plane passing through the axis of the main pipe (1); α > 0°.

4. A pipe structure for ensuring the compactness of concrete pouring inside the pipe according to any one of claims 1 to 2, characterized in that, The main pipe (1) is also provided with a stiffening structure (5); at least one of the air vents (4) is provided at the connection between the main pipe (1) and the stiffening structure (5).

5. A steel-concrete composite bridge, comprising steel-concrete composite components; characterized in that, The steel pipe of the steel-concrete composite member adopts a pipe structure as described in any one of claims 1 to 4 to ensure the compactness of the concrete pouring inside the pipe.

6. A steel-concrete composite bridge according to claim 5, characterized in that, The main pipeline is filled with concrete; the concrete is self-compacting shrinkage-compensating concrete.

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