Connecting structure for improving stability of membrane surface node of gas membrane structure in fire hazard

Abstract

The invention discloses a connecting structure for improving the membrane surface node stability of a gas membrane structure in a fire disaster, relates to the technical field of membrane structure building fire prevention, and solves the problem that node connection of an existing gas membrane structure is prone to failure under the high-temperature condition of the fire disaster. The structure comprises an outer film structure, a plurality of heat insulation structures and a structure foundation, the outer film structure is arranged on the structure foundation, the outer film structure is formed by sequentially overlapping a plurality of outer films, and outer film nodes are formed at the overlapping positions; a heat insulation structure is arranged at the outer film joint and comprises an inner film, the two ends of the inner film are connected with the outer films on the left side and the right side of the outer film joint respectively, and the outer film joint is wrapped in the inner film. And a thermal insulation material is arranged in the inner film. The heat insulation structure is arranged at the outer membrane node position, so that the structural integrity and sealing reliability of the membrane surface node area under the action of extreme temperature are remarkably improved, the weld joint disengagement damage is delayed or avoided, and the fire-resistant safety performance of the whole structure is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fire protection technology for membrane structures, and particularly to a connection structure for improving the stability of membrane surface nodes of air-supported membrane structures under fire conditions. Background Technique

[0002] In recent years, due to advantages such as short construction period, economical cost, light self-weight, and strong construction adaptability, air-supported membrane structures have been widely used in various fields such as stadiums, logistics warehouses, commercial exhibition halls, and large temporary buildings. This structural form relies on maintaining the internal air pressure higher than the external atmospheric pressure, so that the membrane surface is under tension to form a stable spatial curved surface. Since the width of the membrane material itself is limited, multiple connection nodes are inevitably formed during the membrane surface assembly process. Therefore, the membrane surface node connection structure not only directly affects the mechanical properties of the air-supported membrane structure, but also becomes a key factor determining its safety and reliability under extreme loads such as fire.

[0003] In existing engineering practices, the most common node connection method is the hot fusion welding process, that is, by heating and pressurizing the end of the membrane material at high temperature to make it melt and then weld into a whole. This method can provide good airtightness and certain tensile strength under normal temperature conditions, and has convenient construction and controllable cost, so it has been widely used. However, in a fire environment, this type of connection method exposes obvious defects: Fire tests show that when the air temperature rises to about 120°C, the hot fusion weld area will undergo debonding, warping, or even tearing failure, becoming the earliest failed part in the air-supported membrane structure. And this temperature is significantly lower than the thermal decomposition starting temperature of common membrane material bodies (such as PVC membrane materials) (about 250°C - 400°C), indicating that the membrane surface connection part has become a weak link and "short board" in the fire resistance performance of the overall structure. Although some air-supported membrane structures adopt a double-layer membrane design due to heat preservation requirements, however, due to considerations of construction simplification and node force transfer efficiency, the inner layer membrane nodes often directly correspond to the outer layer membrane surface nodes, and no independent thermal stability protection design is introduced in the node area, which makes the structure still likely to be quickly damaged due to local node failure in a fire. In addition, sewing connection is also a way of membrane material node connection. Although it has good thermal stability and can maintain certain mechanical properties without relying on hot melt materials, due to its inherent defects such as perforation, low tensile strength of the sewing thread, and poor joint sealing performance, it is also difficult to meet the airtightness and load-bearing requirements of the structure under fire, especially more likely to fail under the impact of high-temperature air flow or internal pressure disturbance.

[0004] In summary, the existing connection methods for membrane structure nodes perform well under normal working conditions, but there are common technical drawbacks such as high thermal sensitivity and single failure mode in high-temperature fire environments. In order to effectively improve the safety of air-supported membrane structures under extreme fire conditions, delay the structural damage process, and ensure personnel evacuation and emergency response, there is an urgent need to develop a new type of fire-resistant node connection structure with high-temperature resistance to achieve high-reliability operation of air-supported membrane structures in fire scenarios. Summary of the Invention

[0005] In order to solve the problem that the node connection of the existing air-supported membrane structure is prone to failure under fire high-temperature conditions mentioned above, the present invention hereby proposes a connection structure for improving the stability of the membrane surface nodes of the air-supported membrane structure under fire. By setting a heat insulation structure at the outer membrane node position, the present invention significantly improves the structural integrity and sealing reliability of the membrane surface node area under extreme temperature effects, delays or avoids the disconnection failure of the weld, thereby enhancing the fire resistance safety performance of the entire structure.

[0006] The present invention proposes a connection structure for improving the stability of the membrane surface nodes of the air-supported membrane structure under fire, which specifically includes an outer membrane structure, a plurality of heat insulation structures, and a structural foundation. The outer membrane structure is arranged on the structural foundation and is composed of a plurality of outer membranes overlapping in sequence, and the overlapping position forms an outer membrane node; a heat insulation structure is arranged at the outer membrane node, and the heat insulation structure includes an inner membrane, and both ends of the inner membrane are respectively connected to the outer membranes on the left and right sides of the outer membrane node, covering the outer membrane node inside the inner membrane.

[0007] Furthermore, heat insulation materials are arranged inside the inner membrane.

[0008] Furthermore, the heat resistance temperature of the heat insulation materials is not lower than the thermal decomposition temperature of the outer membrane and the inner membrane.

[0009] Furthermore, the heat insulation materials are glass fiber composite cotton, flame retardant foam board, or heat insulation air layer.

[0010] Furthermore, the cross-section of the inner membrane is a semi-circular structure.

[0011] Furthermore, bending structures are arranged at both ends of the inner membrane and are connected to the outer membrane through the bending structures.

[0012] Furthermore, the bending structures are arranged inside the inner membrane.

[0013] The beneficial effects of the connection structure for improving the stability of the membrane surface nodes of the air-supported membrane structure under fire described in the present invention are as follows: (1) The connection structure for improving the stability of the membrane surface nodes of the air-supported membrane structure under fire described in the present invention adopts a sandwich structure composed of an inner membrane, an outer membrane, and heat insulation materials, effectively delaying the heat conduction to the outer membrane weld, thereby significantly enhancing the overall fire resistance of the node, and significantly improving the fire protection performance of the node.

[0014] (2) The connection structure for improving the stability of the membrane surface nodes of the air-supported structure in case of fire according to the present invention can effectively control the overall material consumption by adopting the method of local inner membrane and heat insulation belt compared with the method of improving the fire resistance performance by widening the weld seam as a whole or thickening the membrane material, achieving the goals of light structure and high construction efficiency, and being beneficial to saving materials and construction costs.

[0015] (3) The connection structure for improving the stability of the membrane surface nodes of the air-supported structure in case of fire according to the present invention is applicable to the existing heat sealing process and membrane splicing technology, has good modular manufacturing and on-site rapid assembly capabilities, can meet the requirements of industrial production and large-scale construction, and has strong construction adaptability. Brief Description of the Drawings

[0016] The drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0017] In the drawings: Figure 1 is a top view of the membrane surface node distribution of the connection structure for improving the stability of the membrane surface nodes of the air-supported structure in case of fire according to the present invention; Figure 2 is a schematic diagram of the node connection structure and heat insulation structure of the connection structure for improving the stability of the membrane surface nodes of the air-supported structure in case of fire according to the present invention; Figure 3 is a distribution diagram of the cross-section in the long axis direction of the air-supported structure of the connection structure for improving the stability of the membrane surface nodes of the air-supported structure in case of fire according to the present invention; Among them: 1 - outer membrane; 2 - outer membrane node; 3 - inner membrane; 4 - inner membrane fixed weld seam; 5 - heat insulation material; 6 - internal space of the air-supported structure; 7 - structural foundation. Detailed Embodiments

[0018] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present invention 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 invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0020] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Specific Embodiment 1: Refer to Figures 1 - 3 Specifically illustrate this embodiment. A connection structure for improving the stability of the membrane surface nodes of the air film structure under fire described in this embodiment specifically includes an outer membrane structure, a plurality of heat insulation structures, and a structure foundation 7. The outer membrane structure is arranged on the structure foundation 7. The outer membrane structure is composed of a plurality of outer membranes 1 lapped in sequence, and the lapping position forms an outer membrane node 2. The outer membrane structure is the main load-bearing layer of the structure, directly bearing the internal air pressure, external wind load, and part of the temperature load, and is the core carrier of the structural stability. The outer membranes 1 are spliced by heat-sealing welding process to achieve continuity and airtightness. Its welds are extremely easy to fail due to heat softening under fire, so key protection is required.

[0023] The heat insulation structure is arranged at the position corresponding to the outer membrane node 2 on the inner side of the internal space 6 of the air film. The heat insulation structure includes an inner membrane 3. The two ends of the inner membrane 3 are respectively connected to the outer membranes 1 on the left and right sides of the outer membrane node 2, and the outer membrane node 2 is wrapped inside the inner membrane 3. The main function of the inner membrane 3 is to construct a heat barrier shielding layer. The inner membrane 3 is only locally arranged in the area of the outer membrane node 2 and does not cover the entire membrane surface. Its geometric range needs to cover at least the width of the heat-sealing weld of the outer membrane 1 and the fixed welds on both sides of the inner membrane 3 itself. The fixed welds of the inner membrane 3 significantly reduce the contact area with the high-temperature air in the fire, and most of the fixed welds do not bear the main load, so they can have good integrity under high-temperature fire.

[0024] The inner membrane 3 is provided with a heat-insulating material 5, forming a sandwich structure composed of the inner membrane 3, the outer membrane 1 and the heat-insulating material 5; the heat-insulating material 5 is the core protection component, which needs to have excellent high-temperature resistance and thermal inertia, and can effectively inhibit the inward conduction of heat generated by external fire sources, reducing the temperature rise rate in the weld area of the outer membrane 1; the heat-resistant temperature of the heat-insulating material 5 is not lower than the thermal decomposition temperature of the outer membrane 1 and the inner membrane 3 to ensure that its heat-insulating function can still be maintained in the initial or intermediate stage of a fire, significantly delaying the time window for the heat-sealed weld area to reach the failure temperature; the heat-insulating material 5 is made of glass fiber composite cotton, flame-retardant foam board, etc.

[0025] The cross-section of the inner membrane 3 is a semi-circular structure, with bending structures provided at both ends, and is welded and connected to the outer membrane 1 through the bending structures to form an inner membrane fixed weld 4. The bending structures are arranged inside the inner membrane 3 to protect the inner membrane fixed weld 4 and prevent the occurrence of heat-affected connection failure.

[0026] In terms of construction technology, a method of combining local pre-laying of the inner membrane 3 with synchronous heat-sealing of the outer membrane 1 is adopted, that is, the inner membrane 3 and the heat-insulating material 5 are pre-arranged in the main process stage of heat-sealing welding, so that they are simultaneously closed with the outer membrane 1 to form a multi-layer composite structure. This method avoids problems such as material waste and complex welding control caused by traditional full-film surface multi-layer coating, and realizes an effective balance between fire protection performance and construction economy.

[0027] Specific Embodiment 2: For a connection structure for improving the stability of the membrane surface nodes of an air-supported membrane structure in a fire described in this embodiment, the inner membrane 3 is hollow inside and encloses a heat-insulating air layer with the outer membrane 1, and the air with a small heat conduction coefficient is used to protect the outer membrane node 2. The other components and connection relationships of this embodiment are the same as those of Specific Embodiment 1.

[0028] Summarizing the above embodiments, for a connection structure for improving the stability of the membrane surface nodes of an air-supported membrane structure in a fire described in the present invention, a sandwich structure composed of the inner membrane 3, the outer membrane 1 and the heat-insulating material 5 is adopted, which effectively delays the heat conduction to the outer membrane weld, thus significantly enhancing the overall fire resistance of the nodes and significantly improving the fire protection performance of the nodes. For a connection structure for improving the stability of the membrane surface nodes of an air-supported membrane structure in a fire described in the present invention, compared with the method of improving the fire protection performance by widening the weld as a whole or thickening the membrane material, the method of using the local inner membrane 3 and the heat-insulating belt can effectively control the overall material consumption, achieve the goals of a light structure and high construction efficiency, and is beneficial to saving materials and construction costs. For a connection structure for improving the stability of the membrane surface nodes of an air-supported membrane structure in a fire described in the present invention, the structure is applicable to the existing heat-sealing process and membrane material splicing technology, has good modular manufacturing and on-site rapid assembly capabilities, can meet the needs of industrial production and large-scale construction, and has strong construction adaptability.

[0029] The specific embodiments described above further elaborate on the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the invention. It can also be a reasonable combination of the features described in the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A connection structure for improving the stability of the membrane surface nodes of the air-supported structure under fire, characterized in that: It includes an outer membrane structure, several heat insulation structures and a structural foundation (7). The outer membrane structure is arranged on the structural foundation (7) and is composed of several outer membranes (1) lapped in sequence, and the lapping positions form outer membrane nodes (2). Heat insulation structures are arranged at the outer membrane nodes (2). Each heat insulation structure includes an inner membrane (3). The two ends of the inner membrane (3) are respectively connected to the outer membranes (1) on the left and right sides of the outer membrane node (2), and the outer membrane node (2) is wrapped inside the inner membrane (3).

2. The connection structure for improving the stability of the membrane surface nodes of the air-supported structure under fire according to claim 1, wherein: Heat insulation material (5) is arranged inside the inner membrane (3).

3. The connection structure for improving the stability of the membrane surface nodes of the air-supported structure under fire according to claim 2, characterized in that: The heat resistant temperature of the heat insulation material (5) is not lower than the thermal decomposition temperatures of the outer membrane (1) and the inner membrane (3).

4. The connection structure for improving the stability of the membrane surface nodes of the air-supported structure under fire according to claim 3, characterized in that: The heat insulation material (5) is glass fiber composite cotton or a flame retardant foam board.

5. The connection structure for improving the stability of the membrane surface nodes of the air-supported structure under fire according to claim 1, characterized in that: The cross-section of the inner membrane (3) is a semi-circular structure.

6. The connection structure for improving the stability of the membrane surface nodes of the air-supported structure under fire according to claim 5, characterized in that: Both ends of the inner membrane (3) are provided with bending structures and are connected to the outer membrane (1) through the bending structures.

7. The connection structure for improving the stability of the membrane surface nodes of the air-supported structure under fire according to claim 6, characterized in that: The bending structures are arranged inside the inner membrane (3).

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