Fire prevention method for fireproof prestressed tendon

Abstract

The invention relates to a fire prevention method for a fireproof prestressed tendon, which comprises the following steps: 1, when a fire occurs, a fire sensor detects a fire signal, and a water injection device injects water into a heat insulation fire-resistant cavity between an inner sleeve and an outer sleeve through a water injection port on a middle connector and / or an end connector; secondly, water in the heat insulation fire-resistant cavity absorbs heat and boils, and steam generated by boiling is exhausted from corresponding steam exhaust ports in the middle connector and / or the end connectors; thirdly, after steam in the heat-insulation fire-resistant cavity is exhausted through a steam exhaust port, a vacuum area is formed in the heat-insulation fire-resistant cavity, and heat insulation is achieved; fourthly, heat is transmitted to the fireproof material sleeve through the inner sleeve, and the fireproof material sleeve plays a heat insulation role; and fifthly, heat is transmitted to a fireproof coating layer on the periphery of the center rib through the fireproof material sleeve, and the fireproof coating layer plays a heat insulation role. The invention provides the fire prevention method for the fireproof prestressed tendon, which can realize multi-layer fire prevention when a fire occurs.

Description

Technical Field

[0001] The invention relates to the technical field of fire prevention in building construction, and in particular to a method for preventing fire from occurring when fire-proof prestressed reinforcement bars are in contact with fire. Background Art

[0002] Carbon Fiber Reinforced Polymer (CFRP) bars are a new type of composite material that uses carbon fiber as a reinforcing material, synthetic resin as a matrix material, and an appropriate amount of auxiliary agents. They are combined in a certain proportion and formed through a composite process such as pulling, pressing, extruding, and special surface treatment. Its main forms include plain round bars, deformed bars (notched, ribbed, single helix, double helix, etc.) and stranded wires. In the prestressed CFRP bars used in civil engineering, the glass transition temperature of the resin matrix is ​​low, and the resin burns when exposed to fire, causing its mechanical properties to deteriorate rapidly. With the application of prestressed CFRP bars in public construction projects such as gymnasiums, theaters, and shopping malls, they are required to have fireproof functions to ensure the safety of the structure. Summary of the invention

[0003] The object of the present invention is to provide a fire protection method for fire-proof prestressed tendons which can achieve multi-level fire protection when a fire occurs.

[0004] In order to solve the above technical problems, the technical solution of a fire-proof method for fire-proofing prestressed tendons in the present invention is as follows: A fireproof method for fireproof prestressed tendons, the fireproof method comprising the following steps: a first step, when a fire occurs, a fire sensor detects a fire signal, and a water injection device injects water into the heat-insulating fire-resistant cavity between an inner sleeve and an outer sleeve through a water injection port on an intermediate connector and / or an end connector; In the second step, the water in the heat-insulating refractory cavity absorbs heat and boils, and the steam generated by boiling is discharged from the corresponding exhaust ports on the intermediate connector and / or the end connector; In the third step, after the steam in the heat-insulating refractory cavity is discharged from the exhaust port, a vacuum area is formed in the heat-insulating refractory cavity to achieve heat insulation; In the fourth step, the heat is transferred to the fireproof material casing through the inner casing, and the fireproof material casing plays a role of heat insulation; In the fifth step, the heat is transmitted to the fire-retardant coating layer around the central rib through the fire-retardant material casing, and the fire-retardant coating layer plays a heat-insulating role.

[0005] Furthermore, the fireproof prestressed tendon includes a central tendon, the outer periphery of the central tendon is coated with a fireproof coating layer, the outer periphery of the fireproof coating layer is connected with a fireproof material sleeve, the outer periphery of the protective material sleeve is connected with an inner sleeve, and the fireproof prestressed tendon also includes an outer sleeve coaxially sleeved on the outer periphery of the inner sleeve, and a heat-insulating and fire-resistant cavity is formed between the inner sleeve and the outer sleeve and is ring-shaped around the outer periphery of the fireproof material sleeve.

[0006] Furthermore, both the inner sleeve and the outer sleeve are multi-section structures arranged in sequence along the axial direction of the central rib. The two adjacent sections of the inner sleeve are called the first inner sleeve and the second inner sleeve, and the two adjacent sections of the outer sleeve are called the first outer sleeve and the second outer sleeve. The fire-proof prestressed tendon also includes an intermediate connector for connecting the two adjacent sections of the inner sleeve and the two adjacent sections of the outer sleeve. The center of the intermediate connector has a connector center hole for the fire-proof material sleeve to pass through. The upper end of the hole wall of the connector center hole is threadedly connected to the outer periphery of the first inner sleeve, and the lower end of the hole wall of the connector center hole is threadedly connected to the outer periphery of the second inner sleeve; the outer periphery upper end of the intermediate connector is threadedly connected to the inner periphery of the first outer sleeve, and the outer periphery lower end of the intermediate connector is threadedly connected to the inner periphery of the upper end of the second outer sleeve.

[0007] Furthermore, the intermediate connector is provided with an intermediate connector water injection port and an intermediate connector steam exhaust port, and the intermediate connector steam exhaust port is provided with an intermediate connector steam exhaust valve.

[0008] Furthermore, the insulating refractory cavity includes an upper insulating refractory cavity surrounded by a first outer sleeve and a first inner sleeve and a lower insulating refractory cavity surrounded by a second outer sleeve and a second inner sleeve, and a plurality of connector perforations are circumferentially spaced on the intermediate connector, and the connector perforations penetrate the intermediate connector in the up-and-down directions to realize the connection between the upper insulating refractory cavity and the lower insulating refractory cavity.

[0009] Furthermore, the fire-proof prestressed tendon also includes an end connector, which includes a connector end and an end connector inner tube and an end connector outer tube fixed on the connector end plate, the inner periphery of the end connector inner tube is threadedly connected to the end of the inner sleeve, and the outer periphery of the end connector outer tube is threadedly connected to the end of the outer sleeve.

[0010] Furthermore, the end connector is provided with an end connector water injection port and an end connector steam exhaust port, and the end connector steam exhaust port is provided with an end connector steam exhaust valve.

[0011] Furthermore, the water injection device includes a water tank and a water pump, the water pump is connected to the corresponding connector water injection port through a water pipe, and the fire sensor is at least one of a smoke sensor, a temperature sensor or a visual fire detection sensor.

[0012] The beneficial effects of the present invention are as follows: in the present invention, a heat-insulating refractory cavity is formed between the inner sleeve and the outer sleeve. When no fire occurs, there is no water in the heat-insulating refractory cavity, which is filled with air, so that the weight of the water will not act on the central rib and affect the normal use of the central rib, and there will be no corresponding waterproofing problem; when a fire occurs, the water injection device fills the heat-insulating refractory cavity with water, and the heat is first absorbed by the water, and the water plays the first layer of heat-insulating and fire-proofing role; when the water becomes steam and is discharged from the corresponding exhaust port, the steam takes away the air in the heat-insulating refractory cavity, so that the heat-insulating refractory cavity is in a vacuum state to achieve secondary insulation; as the fire continues, the fire-proof material sleeve and the fire-proof coating layer provide insulation protection for the central rib.

[0013] Furthermore, the fireproof material sleeve, inner sleeve and outer sleeve are independent of the central rib and can be prefabricated in a factory and assembled on site. Fireproof reliability can be guaranteed. At the same time, since it is relatively easy to manufacture and replace, when damage occurs, as long as the central rib itself is not obstructed, other parts can be replaced.

[0014] Furthermore, by changing the inner diameter of the outer sleeve, and thus the inner diameter of the fireproof and heat-insulating cavity, the requirements of various fire resistance levels can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein: Figure 1 It is a structural schematic diagram of an embodiment of the fireproof prestressed tendons in the present invention; Figure 2 yes Figure 1 A top view of Figure 3 is a schematic diagram of the cooperation between the intermediate connector and the first inner sleeve, the first outer sleeve, the second inner sleeve, and the second outer sleeve in this embodiment; Figure 4 Schematic diagram of the cooperation between the end connector, the inner sleeve and the outer sleeve in this embodiment; Figure 5 yes Figure 4 A schematic diagram of the structure of the middle end connector; Figure 6 yes Figure 4 Schematic diagram of cooperation with the water tank of the water injection device; Figure 7 is a schematic structural diagram of an intermediate connector in this embodiment; Figure 8 yes Figure 7 AA section view; Fig. 9 It is a schematic diagram of the distribution of end connectors when multiple center ribs are arranged to form a prestressed tendon bundle in the present invention; 1. Central rib; 2a. Fire-retardant coating layer; 2b. Fire-retardant material sleeve; 3. Inner sleeve; 4. Outer sleeve; 5. Insulating refractory cavity; 6. Intermediate connector; 7. Connector perforation; 8. First inner sleeve; 9. First outer sleeve; 10. Upper insulating refractory cavity; 11. Second inner sleeve; 12. Second outer sleeve; 13. Lower insulating refractory cavity; 14. End connector; 15. Connector end plate; 16. End connector inner tube; 17. End connector outer tube; 18. Connector center hole; 19. Water inlet; 20. End connector exhaust port; 21. End connector exhaust valve; 22. Water pipe solenoid valve; 23. Water pipe; 24. Water tank; 25. Water pump. DETAILED DESCRIPTION

[0016] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are provided in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0017] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0018] The fire protection method of a fire-proof prestressed reinforcement in the present invention is implemented as follows: Figures 1 to 9 As shown: The fire prevention method comprises the following steps: first, when a fire occurs, a fire sensor detects a fire signal, and a water injection device injects water into the heat-insulating fire-resistant cavity between the inner sleeve and the outer sleeve through a water injection port on the middle connector and / or the end connector; In the second step, as the fire continues, the water in the heat-insulating refractory cavity absorbs heat and boils, and the steam generated by the boiling is discharged from the corresponding exhaust ports on the intermediate connector and / or the end connector; In the third step, after the steam in the heat-insulating refractory cavity is discharged from the exhaust port, a vacuum area is formed in the heat-insulating refractory cavity to achieve heat insulation; Step 4: As the fire continues, the heat is transferred to the fireproof material casing through the inner casing, and the fireproof material casing plays a role of heat insulation; In the fifth step, the heat is transmitted to the fire-retardant coating layer around the central rib through the fire-retardant material casing, and the fire-retardant coating layer plays a heat-insulating role.

[0019] In this embodiment, there are multiple fire-proof prestressed tendons, and the multiple fire-proof prestressed tendons form a prestressed tendon bundle.

[0020] The fireproof prestressed tendon includes a central tendon 1, which is a CFRP tendon. The outer periphery of the central tendon 1 is coated with a fireproof coating layer 2a, the outer periphery of the fireproof coating layer 2a is connected with a fireproof material sleeve 2b, and the outer periphery of the fireproof material sleeve 2b is connected with an inner sleeve 3. The fireproof prestressed tendon also includes an outer sleeve 4 coaxially sleeved on the outer periphery of the inner sleeve, and a heat-insulating and fire-resistant cavity 5 is formed between the inner sleeve 3 and the outer sleeve 4 and is arranged around the outer periphery of the fireproof material sleeve.

[0021] In this embodiment, the fireproof material sleeve 2b is a prefabricated filled fireproof material sleeve; the inner sleeve 3 and the outer sleeve 4 are both steel sleeves.

[0022] The inner sleeve 3 and the outer sleeve 4 are both multi-section structures arranged in sequence along the axial direction of the central rib. The two adjacent sections of the inner sleeve are called the first inner sleeve 8 and the second inner sleeve 11, and the two adjacent sections of the outer sleeve are called the first outer sleeve 9 and the second outer sleeve 12. The fire-resistant prestressed tendons also include an intermediate connector 6 for connecting the two adjacent sections of the inner sleeve and the two adjacent sections of the outer sleeve. The intermediate connector 6 plays the role of connecting the first outer sleeve 9 and the first inner sleeve 8, and connecting the second outer sleeve 12 and the second inner sleeve 11. At the same time, the intermediate connector also plays the role of controlling the distance between the inner sleeve and the outer sleeve and maintaining the coaxiality of the inner sleeve and the outer sleeve. The intermediate connector is made of light fireproof materials, such as rock wool board, slag wool board, glass wool board and calcium silicate board.

[0023] The center of the intermediate connector has a connector center hole 18 for the fireproof material sleeve to pass through, the upper end of the hole wall of the connector center hole 18 is threadedly connected to the outer periphery of the first inner sleeve, and the lower end of the hole wall of the connector center hole 18 is threadedly connected to the outer periphery of the second inner sleeve; the upper end of the outer periphery of the intermediate connector 6 is threadedly connected to the inner periphery of the first outer sleeve 8, and the lower end of the outer periphery of the intermediate connector 6 is threadedly connected to the inner periphery of the upper end of the second outer sleeve 12. In other words, the hole wall of the connector center hole 18 of the intermediate connector has a connecting thread, the outer periphery of the intermediate connector has a connecting thread, and the adjacent ends of the first inner sleeve and the second inner sleeve and the adjacent ends of the second inner sleeve and the second outer sleeve all have connecting threads.

[0024] The thickness of the ends of the outer sleeve and the inner sleeve with connecting threads at both ends is 3mm, which is convenient for setting the connecting threads. The thickness of the inner sleeve and the outer sleeve between the connecting threads at both ends is 0.5mm.

[0025] The insulating refractory cavity includes an upper insulating refractory cavity 10 surrounded by a first outer sleeve and a first inner sleeve, and a lower insulating refractory cavity 13 surrounded by a second outer sleeve and a second inner sleeve. A plurality of connector through holes 7 are arranged at circumferential intervals on the intermediate connector. The connector through holes 7 penetrate the intermediate connector in the up-down direction to realize the connection between the upper insulating refractory cavity 10 and the lower insulating refractory cavity 13.

[0026] The fireproof prestressed tendons also include an end connector 14, which includes a connector end plate 15 and an end connector inner tube 16 and an end connector outer tube 17 fixed on the connector end plate 15. The inner periphery of the end connector inner tube 16 is threadedly connected to the end of the inner sleeve, and the outer periphery of the end connector outer tube 17 is threadedly connected to the end of the outer sleeve. In this embodiment, the end of the center rib is fixed to the end connector 14. When in use, the center rib can be tensioned by tensioning the end connector. The end connector can directly apply the resilience of the center rib to other carriers. Of course, in other embodiments of the present invention, the center rib can also be completely passed through the connector end plate of the end connector. There is no force transmission relationship between the center rib and the end connector. The end connector only plays the role of positioning the inner sleeve and the outer sleeve. The end connector does not affect the tensioning process of the center rib.

[0027] The end connector is provided with an end connector water injection port 19 and an end connector exhaust port 20, and an end connector exhaust valve 21 is provided on the end connector exhaust port. The water injection device includes a water tank 24 and a water pump 25, and the water pump 25 is connected to the corresponding end connector water injection port 19 through a water pipe 23. The fire sensor is at least one of a smoke sensor, a temperature sensor or a visual fire detection sensor. The smoke sensor can be an ion smoke detector, a photoelectric smoke detector, an infrared beam smoke detector and an air sampling smoke detector, etc. The visual fire detection sensor obtains fire information by photographing the flame. The above sensors belong to the prior art and will not be described in detail here. Item 22 in the figure represents a solenoid valve. In other embodiments of the present invention, the intermediate connector may also be provided with an intermediate connector water injection port and an intermediate connector exhaust port, and an intermediate connector exhaust valve is provided on the intermediate connector exhaust port, and the water pipe is connected to the intermediate connector water injection port.

[0028] In this embodiment, the water injection port of the end connector and the steam exhaust port of the end connector are distributed at 180° along the circumference of the end connector. Fig. 9As shown, the six end connectors constitute three groups of end connectors arranged sequentially along the left-right direction, each group of end connectors includes two end connectors arranged sequentially along the front-back direction, the water pipes connected to each end connector are arranged in parallel, and the angles between the water pipes and the left-right direction and the front-back direction are acute angles, and the end connector exhaust valve connected to the end connector at the front position is located between the water pipes of the two adjacent end connectors at the rear position in the left-right direction, which can save space.

[0029] In the above description of this specification, unless otherwise clearly specified and limited, the terms "fixed", "installed", "connected" or "connected" should be understood in a broad sense. For example, with regard to the term "connection", it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. Therefore, unless otherwise clearly defined in this specification, those skilled in the art can understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0030] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "length", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", "center", "longitudinal", "lateral", "clockwise" or "counterclockwise", etc., which indicate the orientation or position relationship, are based on the orientation or position relationship shown in the drawings of this specification, and are only for the purpose of facilitating the explanation of the scheme of the present invention and simplifying the description, rather than explicitly or implicitly indicating that the device or element involved must have the specific orientation, be constructed and operate in a specific orientation. Therefore, the above-mentioned orientation or position relationship terms cannot be understood or interpreted as limitations on the scheme of the present invention.

[0031] In addition, the terms "first" or "second" used in this specification to refer to numbers or ordinals are only used for descriptive purposes and cannot be understood as explicitly or implicitly indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this specification, the meaning of "plurality" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically defined.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preventing fire from occurring when fire-resistant prestressed tendons is characterized by: The fire prevention method comprises the following steps: first, when a fire occurs, a fire sensor detects a fire signal, and a water injection device injects water into the heat-insulating fire-resistant cavity between the inner sleeve and the outer sleeve through a water injection port on the middle connector and / or the end connector; In the second step, the water in the heat-insulating refractory cavity absorbs heat and boils, and the steam generated by boiling is discharged from the corresponding exhaust ports on the intermediate connector and / or the end connector; In the third step, after the steam in the heat-insulating refractory cavity is discharged from the exhaust port, a vacuum area is formed in the heat-insulating refractory cavity to achieve heat insulation; In the fourth step, the heat is transferred to the fireproof material casing through the inner casing, and the fireproof material casing plays a role of heat insulation; In the fifth step, the heat is transmitted to the fire-retardant coating layer around the central rib through the fire-retardant material casing, and the fire-retardant coating layer plays a heat-insulating role.

2. The fire prevention method according to claim 1, characterized in that: The fireproof prestressed tendon includes a central tendon, the outer periphery of the central tendon is coated with a fireproof coating layer, the outer periphery of the fireproof coating layer is connected with a fireproof material sleeve, the outer periphery of the protective material sleeve is connected with an inner sleeve, and the fireproof prestressed tendon also includes an outer sleeve coaxially sleeved on the outer periphery of the inner sleeve, and a heat-insulating and fire-resistant cavity is formed between the inner sleeve and the outer sleeve and is arranged around the outer periphery of the fireproof material sleeve.

3. The fire prevention method according to claim 2, characterized in that: Both the inner sleeve and the outer sleeve are multi-section structures arranged in sequence along the axial direction of the central rib. The two adjacent sections of the inner sleeve are called the first inner sleeve and the second inner sleeve, and the two adjacent sections of the outer sleeve are called the first outer sleeve and the second outer sleeve. The fire-proof prestressed tendon also includes an intermediate connector for connecting the two adjacent sections of the inner sleeve and the two adjacent sections of the outer sleeve. The center of the intermediate connector has a connector center hole for the fire-proof material sleeve to pass through. The upper end of the hole wall of the connector center hole is threadedly connected to the outer circumference of the first inner sleeve, and the lower end of the hole wall of the connector center hole is threadedly connected to the outer circumference of the second inner sleeve; the outer circumference upper end of the intermediate connector is threadedly connected to the inner circumference of the first outer sleeve, and the outer circumference lower end of the intermediate connector is threadedly connected to the inner circumference of the upper end of the second outer sleeve.

4. The fire prevention method according to claim 3, characterized in that: The intermediate connector is provided with an intermediate connector water injection port and an intermediate connector steam exhaust port, and the intermediate connector steam exhaust port is provided with an intermediate connector steam exhaust valve.

5. The fire prevention method according to claim 3, characterized in that: The heat-insulating refractory cavity includes an upper heat-insulating refractory cavity surrounded by a first outer sleeve and a first inner sleeve and a lower heat-insulating refractory cavity surrounded by a second outer sleeve and a second inner sleeve. A plurality of connector perforations are arranged at circumferential intervals on the intermediate connector. The connector perforations penetrate the intermediate connector in the up-and-down directions to realize the connection between the upper heat-insulating refractory cavity and the lower heat-insulating refractory cavity.

6. The fire prevention method according to claim 2, characterized in that: The fireproof prestressed tendons also include an end connector, which includes a connector end and an end connector inner tube and an end connector outer tube fixed on a connector end plate, the inner circumference of the end connector inner tube being threadedly connected to the end of the inner sleeve, and the outer circumference of the end connector outer tube being threadedly connected to the end of the outer sleeve.

7. The fire prevention method according to claim 6, characterized in that: The end connector is provided with an end connector water injection port and an end connector steam exhaust port, and the end connector steam exhaust port is provided with an end connector steam exhaust valve.

8. The fire prevention method according to any one of claims 3 to 7, characterized in that: The water injection device includes a water tank and a water pump, the water pump is connected to the corresponding connector water injection port through a water pipe, and the fire sensor is at least one of a smoke sensor, a temperature sensor or a visual fire detection sensor.

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