A prestressed continuous beam 0# block mass concrete temperature control device

Abstract

The utility model discloses a kind of prestressed continuous beam 0# block mass concrete temperature control device, including sequentially embedding in mass concrete from top to bottom several steel pipes, the outside of steel pipe is evenly distributed with several cooling fins, the inner chamber of steel pipe constitutes prestressed hole, several steel pipes are connected by connecting pipe head-to-tail and constitute cooling water flow channel, the water inlet end of cooling water flow channel is connected with water delivery pipe, flow valve and flowmeter are equipped on water delivery pipe, the surface and interior of mass concrete are evenly equipped with temperature sensor, the temperature sensor, flow valve and flowmeter are connected with controller. The device is improved by prestressed hole on mass concrete, directly using prestressed hole to act as cooling water flow channel, to effectively overcome the problem that traditional cooling water pipe may conflict with prestressed hole position when crossing web area.

Description

Technical Field

[0001] This utility model belongs to the field of bridge engineering technology, and in particular relates to a temperature control device for large-volume concrete of prestressed continuous beam 0# block. Background Technology

[0002] Currently, with the continuous increase in bridge spans, the dimensions of continuous box girder structures are also constantly increasing. The 0# block of the box girder, as the first segment of the continuous beam, generally has local dimensions exceeding 3m in its bottom plate, web, and diaphragms, reaching the category of large-volume concrete. Measures should be taken to avoid temperature cracks caused by excessive hydration heat. To address this, patent CN2023214318601 discloses a hydration heat control device for the 0# block of a continuous beam, which uses cooling water pipes installed inside the concrete to circulate cold water and absorb the internal hydration heat. However, in actual construction, the 0# block concrete has numerous prestressed ducts and dense reinforcement, leading to the following problems when arranging the cooling water pipes: the cooling water pipe routing often conflicts with the prestressed ducts, especially near the web area; to avoid conflicts, it is necessary to increase the detour path of the cooling water pipes, resulting in material waste and reduced water cooling efficiency. Summary of the Invention

[0003] The main purpose of this utility model is to provide a temperature control device for large-volume concrete of prestressed continuous beam 0# block. This device improves the prestressed ducts on the large-volume concrete and directly uses the prestressed ducts as cooling water channels, thereby effectively overcoming the problem that the traditional cooling water pipes may conflict with the position of the prestressed ducts when passing through the web area.

[0004] Therefore, the main objective of this utility model is to provide a temperature control device for a prestressed continuous beam 0# block of large-volume concrete, comprising several steel pipes embedded sequentially from top to bottom in the large-volume concrete. Several cooling fins are evenly distributed on the outside of the steel pipes, and the inner cavity of the steel pipes forms a prestressed channel. Several steel pipes are connected end to end by connecting pipes to form a cooling water channel. The inlet end of the cooling water channel is connected to a water supply pipe. A flow valve and a flow meter are provided on the water supply pipe. Temperature sensors are evenly distributed on the surface and inside of the large-volume concrete. The temperature sensors, flow valve, and flow meter are all connected to a controller.

[0005] Specifically, the steel pipe is provided with connecting flanges at both ends, and the connecting pipe is provided with mating flanges at both ends that mate with the connecting flanges. The connecting flanges and the mating flanges are connected by connecting bolts.

[0006] Specifically, multiple cooling water channels are arranged in the large-volume concrete, and each cooling water channel is connected to the main water pipe through a water supply pipe, and a water pump is installed on the main water pipe.

[0007] Specifically, it also includes a circulating water tank, and the outlet end of each of the cooling water flow channels is connected to the return main pipe through a return branch pipe. The return main pipe is connected to the circulating water tank, and the main water pipe is connected to the circulating water tank.

[0008] Compared with the prior art, the present invention has the following beneficial effects: by pre-embedding steel pipes in large-volume concrete, the inner cavity of the steel pipes forms the prestressing channels for subsequent prestressing tendons to pass through. Several steel pipes are connected end to end by connecting pipes to form a cooling water channel. Cooling water is introduced into the cooling water channel to cool the large-volume concrete. The cooling fins evenly distributed on the outside of the steel pipes can increase the heat dissipation area and improve the heat dissipation efficiency, effectively controlling the temperature rise of the concrete hydration heat and the temperature difference between the inside and outside, so as to prevent the generation of temperature cracks. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the temperature control device for the prestressed continuous beam 0# block large-volume concrete provided in this embodiment of the utility model. Figure 2 This is a partial schematic diagram of the large-volume concrete in the web region involved in an embodiment of this utility model; The components are: 1. Steel pipe; 2. Cooling fins; 3. Prestressed ducts; 4. Connecting pipe; 5. Water supply pipe; 6. Flow valve; 7. Flow meter; 8. Temperature sensor; 9. Controller; 10. Connecting flange; 11. Butt flange; 12. Connecting bolts; 13. Main water pipe; 14. Water pump; 15. Circulating water tank; 16. Return branch pipe; 17. Return main pipe. Detailed Implementation

[0011] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0012] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model.

[0013] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, the meaning of "plural" is two or more, unless otherwise specifically and clearly defined.

[0014] See Figure 1 and Figure 2 , a temperature control device for mass concrete of the 0# block of a prestressed continuous beam, comprising a plurality of steel pipes 1预埋 in the mass concrete of the web area in sequence from top to bottom. A plurality of cooling fins 2 are evenly distributed on the outer part of the steel pipes 1. The inner cavity of the steel pipes 1 forms a prestressed duct 3. A plurality of steel pipes 1 are connected end to end through connecting pipes 4 to form a cooling water flow path. The water inlet end of the cooling water flow path is connected to a water delivery pipe 5. A flow valve 6 and a flowmeter 7 are provided on the water delivery pipe 5. Temperature sensors 8 are evenly arranged on the surface and inside of the mass concrete. The temperature sensors 8, the flow valve 6 and the flowmeter 7 are all connected to a controller 9.

[0015] The specific construction and temperature control process of the above-mentioned mass concrete of the 0# block of the prestressed continuous beam are as follows: a. Construction preparation stage: Bind steel bars, install templates and the steel pipes 1 of the prestressed duct 3. Connect the steel pipes 1 in each vertical row end to end through the connecting pipes 4 to form a cooling water flow path, and connect the water inlet end of the cooling water flow path to the water delivery pipe 5. After the installation and positioning of the prestressed duct 3 are completed, conduct a water pressure test. The test pressure should preferably be 1.5 times the design operating pressure, and continuously pressurize for 10 - 15 minutes. The qualified standard is that there is no leakage and no interface loosening in the system. After the test is qualified, the water inlet and outlet joints should be promptly sealed and protected. Use a flexible plug to seal the mouth, and add a sealing washer and a plastic protection cap to prevent pollution, deformation or collision during the construction process, and create a safe condition for the subsequent concrete pouring.

[0016] b. Temperature sensor 8 installation: Temperature measuring points are arranged in the web area according to the design requirements. The temperature measuring points are arranged in the middle section of the transverse diaphragm, with a total of 11 measuring points. There are eight surface temperature measuring points, three at the top, two in the middle, three at the bottom, and three inside measuring points. The vertical spacing of each temperature measuring point is 2.7m, and the horizontal spacing is 3.9m. The surface temperature measuring points are 5cm away from the concrete surface.

[0017] c. Concrete pouring: Pour concrete into the project area and vibrate it. The temperature of the concrete at a depth of 50mm to 100mm after vibration should not exceed 28℃.

[0018] d. Temperature Control and Curing: During concrete pouring, the water flow rate in the cooling water channels is adjusted to control the temperature difference between the concrete core and surface to not exceed 20℃, and the cooling rate of the core area concrete to not exceed 2℃ / day. After concrete pouring is completed, geotextile fabric should be immediately used for insulation. During the temperature rise phase, the temperature difference between the concrete core and surface should not exceed 20℃. This is mainly determined by comparing the readings of the temperature sensors in the core area and the surface. If the difference is close to exceeding 20℃, the water flow rate and frequency should be immediately increased to control the temperature difference between the core and surface at 20℃. When the temperature in the core area begins to drop, the cooling rate should be controlled to not exceed 2℃ / day.

[0019] e. Tensioning Prestressing Tendons: After the cooling stage of the upper concrete, the prestressing ducts 3 should be promptly flushed with high-pressure air and clean water to ensure no blockage or residual water, guaranteeing safe and unimpeded prestressing tensioning. Once the concrete reaches its strength grade, the prestressing tendons should be tensioned. Prestressing is completed in a single tensioning operation. The tensioning sequence is: first the web tendons, then the top slab tendons, proceeding symmetrically from the outside in, with timely grouting. A dual-control measure is used for prestressing; the prestress value is based on the oil pressure gauge reading and checked against the prestress elongation. The tensioning sequence is: 0 → initial stress (10%~20% of the final tension control stress) → design tonnage → holding load (static stop for 5 minutes) → anchorage.

[0020] In this embodiment, steel pipes 1 are pre-embedded in the large-volume concrete. The inner cavity of the steel pipes 1 forms the prestressing ducts 3 for subsequent prestressing tendons to pass through. Several steel pipes 1 are connected end to end by connecting pipes 4 to form a cooling water channel. By passing cooling water through the cooling water channel, some of the prestressing ducts 3 in the upper web area of ​​block #0 are set as water cooling channels to cool the large-volume concrete. The cooling fins 2 evenly distributed on the outside of the steel pipes 1 can increase the heat dissipation area and improve the heat dissipation efficiency, effectively control the temperature rise of the concrete hydration heat and the temperature difference between the inside and outside, so as to prevent the generation of temperature cracks. This effectively overcomes the problem that the traditional cooling water pipes may conflict with the position of the prestressing ducts 3 when passing through the web area.

[0021] See Figure 2 In some embodiments, the steel pipe 1 is provided with connecting flanges 10 at both ends, and the connecting pipe 4 is provided with mating flanges 11 that cooperate with the connecting flanges 10 at both ends. The connecting flanges 10 and the mating flanges 11 are connected by connecting bolts 12, thereby realizing the end-to-end connection of adjacent steel pipes 1. The connecting pipe 4 can be a soft corrugated water pipe.

[0022] See Figure 1 Understandably, in the actual design, multiple cooling water channels are arranged within the large-volume concrete. Each cooling water channel is connected to the main water pipe 13 via a water supply pipe 5, and a water pump 14 is installed on the main water pipe 13. To achieve water conservation, the device also includes a circulating water tank 15. The outlet of each cooling water channel is connected to the return main pipe 17 via a return branch pipe 16. The return main pipe 17 is connected to the circulating water tank 15, and the main water pipe 13 is connected to the circulating water tank 15. Alternatively, the water outlet of the return main pipe 17 can be directly guided to the inner cavity of the continuous beam, using the water from the outlet of the return main pipe 17 for water storage and curing. However, attention must be paid to ventilation of the inner cavity, with hot air being exhausted outwards through the manhole in the partition.

[0023] Unless otherwise stated, if any of the technical solutions disclosed in this utility model discloses a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this utility model discloses only some numerical values ​​to illustrate the technical solutions of the invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0024] Meanwhile, if the present invention discloses or relates to mutually fixedly connected parts or structural components, then unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured by casting) (except where it is obviously impossible to use an integral forming process).

[0025] Furthermore, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in this utility model include states or shapes that are similar to, analogous to, or close to those states or shapes. Any component provided by this utility model can be assembled from multiple individual components or can be a single component manufactured using a one-piece molding process.

[0026] The above embodiments are merely illustrative examples to clearly illustrate the present invention, and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A temperature control device for large-volume concrete of prestressed continuous beam 0# block, characterized in that: The system includes several steel pipes (1) embedded in a large volume of concrete from top to bottom. Several cooling fins (2) are evenly distributed on the outside of the steel pipes (1). The inner cavity of the steel pipes (1) forms a prestressed channel (3). Several steel pipes (1) are connected end to end through connecting pipes (4) to form a cooling water channel. The inlet end of the cooling water channel is connected to a water supply pipe (5). A flow valve (6) and a flow meter (7) are provided on the water supply pipe (5). Temperature sensors (8) are evenly distributed on the surface and inside of the large volume of concrete. The temperature sensors (8), flow valves (6) and flow meters (7) are all connected to a controller (9).

2. The temperature control device for large-volume concrete of prestressed continuous beam 0# block according to claim 1, characterized in that: The steel pipe (1) is provided with connecting flanges (10) at both ends, and the connecting pipe (4) is provided with mating flanges (11) at both ends that cooperate with the connecting flanges (10). The connecting flanges (10) and the mating flanges (11) are connected by connecting bolts (12).

3. The temperature control device for large-volume concrete of prestressed continuous beam 0# block according to claim 1 or 2, characterized in that: Multiple cooling water channels are arranged in the large volume concrete. Each cooling water channel is connected to the main water pipe (13) through a water supply pipe (5). A water pump (14) is installed on the main water pipe (13).

4. The temperature control device for large-volume concrete of prestressed continuous beam 0# block according to claim 3, characterized in that: It also includes a circulating water tank (15), and the outlet end of each of the cooling water channels is connected to the return main pipe (17) through a return branch pipe (16). The return main pipe (17) is connected to the circulating water tank (15), and the main water pipe (13) is connected to the circulating water tank (15).

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