Automatic shedding device for large-span roof membrane structure under strong wind

Abstract

The application discloses a kind of automatic shedding devices of large-span roof membrane structure under strong wind action, comprising: clamping plate and clamping core;The clamping plate is provided with the recess of opening upward, the cross section of the recess is trapezoidal, the opening of the recess is arranged on the top side of trapezoidal, the opening width is same with the length of top side, the end of the clamping plate far from the opening is provided with the mounting portion of fixed connection with roof steel structure;The clamping core is the block body of outer contour and recess adaptation, the clamping core is embedded in recess, the end of the clamping core close to opening is provided with the connecting portion of fixed connection with roof membrane material;When the tension in the vertical direction of the clamping core is greater than the set value, the clamping plate and clamping core occur plastic deformation and separate.When the force in the vertical direction of the clamping core exceeds the set value, the clamping core is pulled out from the recess, and the clamping plate fixed on the steel structure is separated, so that the membrane material is timely shed, the effect of unloading is achieved, and the safety and reliability of the large-span steel structure for installing membrane material under extreme gale weather is ensured.

Description

Technical Field

[0001] This invention relates to the field of building structures, and more particularly to an automatic detachment device for large-span roof membrane structures under strong wind conditions. Background Technology

[0002] Membrane materials, with their advantages of being lightweight, self-cleaning, easy to install, and aesthetically pleasing, are widely used in steel structure roofs. On large-span steel structure roofs, the membrane material is typically fixed to the main structure using clamps. When the membrane material is subjected to wind loads, the load is transferred to the steel structure roof members through the clamps. Under extreme wind loads, the steel structure roof members deform, leading to damage to the roof members or even the overall collapse of the structure, which can easily cause casualties and huge economic losses.

[0003] In recent years, accidents involving the destruction of steel roof structures caused by extreme natural disasters such as typhoons and storms have been frequent, resulting in significant economic losses and seriously threatening personal safety. Ensuring the safety and reliability of large-span steel structures with membrane structures under extreme wind conditions is a pressing issue that needs to be addressed. Summary of the Invention

[0004] This invention provides an automatic detachment device for large-span roof membrane structures under strong winds, to ensure the safety and reliability of large-span steel structures with installed membrane materials in extreme windy weather.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] An automatic detachment device for a large-span roof membrane structure under strong wind conditions, comprising: a clamping plate and a core;

[0007] The clamping plate has an upward-opening groove with a trapezoidal cross-section. The opening of the groove is located on the top edge of the trapezoid, and the width of the opening is the same as the length of the top edge. The end of the clamping plate away from the opening is provided with an installation part that is fixedly connected to the roof steel structure.

[0008] The core is a block-shaped body whose outer contour is adapted to the groove. The core is embedded in the groove, and the end of the core near the opening is provided with a connecting part that is fixedly connected to the roof membrane material.

[0009] When the tension in the vertical direction of the core exceeds a set value, the clamping plate and the core undergo plastic deformation and separate.

[0010] Furthermore, the trapezoid is an isosceles trapezoid, and the angle between the leg and the height of the isosceles trapezoid is a first acute angle. The opening of the first acute angle faces the base of the isosceles trapezoid, and the tangent of the first acute angle ranges from 0.02 to 0.25.

[0011] Furthermore, the height of the isosceles trapezoid is 20-60mm, and the length of the top side of the isosceles trapezoid is 20mm.

[0012] Furthermore, the length of the groove is 4-10 mm.

[0013] Furthermore, the length of the groove is 4mm.

[0014] Furthermore, it also includes end baffles, which are fixed to the clamping plate by threaded fasteners; the groove extends through the clamping plate along its thickness direction, and the end baffles are disposed on both sides of the clamping plate to prevent the clamping core from coming out of the groove along the thickness direction of the clamping plate.

[0015] Furthermore, the mounting part is a connecting bolt, and the end of the clamp away from the opening is fixedly connected to the head of the connecting bolt.

[0016] Furthermore, the connecting part is a connecting ring, and the end of the clamp near the opening is fixedly connected to the connecting ring.

[0017] The beneficial effects of this invention are:

[0018] This invention provides an automatic detachment device for large-span roof membrane structures under strong winds, comprising: a clamping plate fixed to a steel structure and a core fixed to the membrane material. The clamping plate holds the core tightly through a groove with a trapezoidal cross-section that is narrower at the top and wider at the bottom, thereby fixing the membrane material to the steel structure. When the tension in the vertical direction of the core exceeds a set value, the core is pulled out from the groove and separated from the clamping plate, allowing the membrane material to detach in time. This interrupts the force transmission path and achieves the effect of unloading, ensuring the safety and reliability of the large-span steel structure with the membrane material installed under extreme wind conditions. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0021] Figure 2a This is a schematic diagram of the structure for removing the connecting parts and the installation parts of an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0022] Figure 2bThis is a schematic diagram of the connection ring and the membrane material connection ring of an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0023] Figure 3 This is a schematic diagram of the clamping plate of an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0024] Figure 4a This is a schematic diagram of the core structure of an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0025] Figure 4b This is a front view of the core of an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0026] Figure 5 This is a schematic diagram of the fixing component of an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0027] Figure 5a The bearing capacity curves of the H20 and H30 devices with different first acute angles for an automatic detachment device for a large-span roof membrane structure under strong wind conditions disclosed in this invention are shown.

[0028] Figure 5b The bearing capacity curves of the automatic detachment device for a large-span roof membrane structure under strong wind action, disclosed in this invention, are shown for devices with different acute angles H40 and H50.

[0029] Figure 5c The bearing capacity curves of H60 devices with different first acute angles for an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention;

[0030] Figure 6a The bearing capacity curves of devices with different pull-out depths when the first acute angle tangent value is 1 / 4 for an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0031] Figure 6b The bearing capacity curves of devices with different pull-out depths when the first acute angle tangent value is 1 / 5 for an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0032] Figure 6c The bearing capacity curves of the automatic detachment device for a large-span roof membrane structure under strong wind action disclosed in this invention are shown when the first acute angle tangent is 1 / 10 and the pull-out depth is different.

[0033] Figure 6dThe bearing capacity curves of devices with different pull-out depths when the first acute angle tangent value of the automatic detachment device for a large-span roof membrane structure under strong wind is 1 / 20, as disclosed in this invention.

[0034] Figure 7a This is a Mises stress cloud diagram of the H20A4 structure when an automatic detachment device for a large-span roof membrane structure under strong winds, as disclosed in this invention, fails.

[0035] Figure 7b This is a Mises stress cloud diagram of the H20A5 of the automatic detachment device for a large-span roof membrane structure under strong wind conditions disclosed in this invention.

[0036] Figure 8a This is a lateral deformation cloud diagram of H20A4 when the automatic detachment device for a large-span roof membrane structure under strong winds, as disclosed in this invention, fails.

[0037] Figure 8b This is a longitudinal deformation cloud diagram of H20A4 when the automatic detachment device for a large-span roof membrane structure under strong winds, as disclosed in this invention, fails.

[0038] Figure 8c This is a lateral deformation cloud diagram of the H20A5 of the automatic detachment device for a large-span roof membrane structure under strong winds disclosed in this invention when it fails.

[0039] Figure 8d This is a longitudinal deformation cloud diagram of H20A5 when the automatic detachment device for a large-span roof membrane structure under strong winds, as disclosed in this invention, fails.

[0040] Figure 9 This is a curve showing the peak bearing capacity variation of an automatic detachment device for a large-span roof membrane structure under strong wind conditions, as disclosed in this invention.

[0041] Figure 10 This is a wind suction envelope diagram of a simulated roof structure under strong wind conditions for an automatic detachment device for a large-span roof membrane structure disclosed in this invention;

[0042] Figure 11a This invention discloses an automatic detachment device for a large-span roof membrane structure under strong wind conditions, showing the axial force cloud diagram of the roof members when the membrane does not detach.

[0043] Figure 11b This invention discloses an automatic detachment device for a large-span roof membrane structure under strong wind conditions, showing the displacement cloud diagram of the roof members when the membrane does not detach.

[0044] Figure 11c This invention discloses a statistical chart showing the stress ratio of roof members when the membrane of an automatic detachment device for a large-span roof membrane structure under strong wind conditions does not detach.

[0045] Figure 12 This is a schematic diagram of the roof when the membrane of the automatic detachment device for a large-span roof membrane structure under strong winds occurs partially (detachment rate 25%).

[0046] Figure 13a This is a cloud diagram of the axial force of the roof members when the membrane of an automatic detachment device for a large-span roof membrane structure under strong winds occurs (detachment rate 25%).

[0047] Figure 13b This invention discloses an automatic detachment device for a large-span roof membrane structure under strong winds. When the membrane partially detaches (detachment rate 25%), the displacement cloud diagram of the roof members is shown.

[0048] Figure 13c This invention discloses a statistical chart showing the stress ratio of roof members when the membrane of an automatic detachment device for a large-span roof membrane structure experiences partial detachment (detachment rate of 25%) under strong wind conditions.

[0049] Figure 14 This is a schematic diagram of the roof when the membrane of the automatic detachment device for a large-span roof membrane structure under strong winds occurs partially (detachment rate 50%).

[0050] Figure 15a This invention discloses an automatic detachment device for a large-span roof membrane structure under strong winds. The axial force cloud diagram of the roof members is shown when the membrane partially detaches (detachment rate 50%).

[0051] Figure 15b This is a displacement cloud diagram of the roof members when the membrane of an automatic detachment device for a large-span roof membrane structure under strong winds occurs (detachment rate 50%).

[0052] Figure 15c This is a statistical chart showing the stress ratio of roof members when the membrane of an automatic detachment device for a large-span roof membrane structure under strong wind conditions occurs (detachment rate 50%).

[0053] Figure 16 This is a schematic diagram of the roof when the membrane of the automatic detachment device for a large-span roof membrane structure under strong winds occurs partially (detachment rate 75%).

[0054] Figure 17a This is a cloud diagram of the axial force of the roof members when the membrane of an automatic detachment device for a large-span roof membrane structure under strong winds occurs (detachment rate 75%).

[0055] Figure 17bThis invention discloses an automatic detachment device for a large-span roof membrane structure under strong winds. The device is shown in the image below. The detachment rate is 75%. The displacement cloud diagram of the roof members is shown below.

[0056] Figure 17c This invention discloses a statistical chart showing the stress ratio of roof members when the membrane of an automatic detachment device for a large-span roof membrane structure experiences partial detachment (detachment rate of 75%) under strong wind conditions.

[0057] Figure 18a This invention discloses an automatic detachment device for a large-span roof membrane structure under strong wind conditions. The axial force cloud diagram of the roof members is shown when the membrane completely detaches.

[0058] Figure 18b This invention discloses an automatic detachment device for a large-span roof membrane structure under strong wind conditions. The device is shown in the image below, which illustrates the displacement cloud diagram of the roof members when the membrane completely detaches.

[0059] Figure 18c This is a statistical chart showing the stress ratio of roof members when the membrane of an automatic detachment device for a large-span roof membrane structure under strong wind conditions is completely detached, as disclosed in this invention.

[0060] In the picture:

[0061] 1. Clamping plate; 11. Groove; 12. Fixing bolt mounting holes;

[0062] 2. Sandwich core;

[0063] 3. End baffles;

[0064] 4. Connecting ring;

[0065] 5. Connecting bolts;

[0066] 6. Fixing bolts;

[0067] α, First acute angle; E, Support side; F, Cantilever side; h, Height of the sandwich core; G, Membrane material; G1, Membrane material connecting ring. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0069] This embodiment provides an automatic detachment device for large-span roof membrane structures under strong winds, such as... Figure 1 and Figure 2a As shown, it includes: a clamping plate 1 and a core 2;

[0070] like Figure 3 As shown, the clamping plate 1 has an upward-opening groove 11. The cross-section of the groove 11 is trapezoidal. The opening of the groove 11 is located on the top edge of the trapezoid. The width of the opening is the same as the length of the top edge. The end of the clamping plate 1 away from the opening is provided with an installation part that is fixedly connected to the roof steel structure.

[0071] like Figure 4a As shown, the core 2 is a block-shaped body whose outer contour is adapted to the groove 11. The core 2 is embedded in the groove 11. The end of the core 2 near the opening is provided with a connecting part that is fixedly connected to the roof membrane material.

[0072] When the vertical tensile force on the core 2 is greater than a set value (the set value is less than the maximum load that the roof steel structure can withstand before failure, ensuring that the core 2 can separate from the clamping plate 1 in time before the steel structure fails, thus avoiding the failure of the steel structure), the clamping plate 1 and the core 2 undergo plastic deformation and separate.

[0073] When the membrane material is subjected to external loads, the connecting part transfers the load to the core 2. The core 2 is in a tensile state. The clamping plate 1 hugs the core 2 through the groove 11 with a trapezoidal cross-section that is narrow at the top and wide at the bottom, and friction is generated at the interface between the two. When the tension in the vertical direction of the core 2 exceeds the set value, the core 2 is completely pulled out, the membrane material separates from the roof steel structure, the force transmission path is interrupted, and the unloading effect is achieved.

[0074] In a specific embodiment, the trapezoid is an isosceles trapezoid, such as... Figure 4b As shown, the angle between the leg and the height of the isosceles trapezoid is the first acute angle α. The opening of the first acute angle α faces the base of the isosceles trapezoid, and the tangent of the first acute angle α ranges from 0.02 to 0.25.

[0075] In a specific embodiment, such as Figure 4b As shown, the height of the isosceles trapezoid (the height h of the core 2) is 20-60mm, and the length of the top side of the isosceles trapezoid is 20mm.

[0076] Preferably, the height of the isosceles trapezoid is 20-40 mm.

[0077] In a specific embodiment, the length of the groove 11 is 4-10 mm.

[0078] In a specific embodiment, the length of the groove 11 is 4mm.

[0079] In a specific embodiment, such as Figure 1 and Figure 2a As shown, it also includes an end baffle 3, which is fixed to the clamping plate 1 by threaded fasteners;

[0080] The groove 11 extends through the clamping plate 1 along the thickness direction, and the end baffle 3 is provided on both sides of the clamping plate 1 to prevent the core 2 from coming out of the groove 11 along the thickness direction of the clamping plate 1.

[0081] In this embodiment, as Figure 2a As shown, the two end baffles 3 are fixed to both sides of the clamping plate 1 by nuts and fixing bolts 6. The end baffles 3 are provided with through holes through which the fixing bolts 6 can pass, such as... Figure 3 As shown, the clamping plate 1 is provided with fixing bolt mounting holes 12 corresponding to the through holes.

[0082] In a specific embodiment, the mounting part is a connecting bolt 5, and the end of the clamping plate 1 away from the opening is welded to the head of the connecting bolt 5. The connecting bolt 5 is connected to the steel structure rod by a thread.

[0083] In a specific embodiment, the connecting part is a connecting ring 4, and the end of the core 2 near the opening is welded to the connecting ring 4, and the membrane material is fixedly connected to the connecting ring 4;

[0084] In practical applications, such as Figure 2b As shown, the membrane material G is provided with a membrane material connecting ring G1. After the connecting ring 4 passes through the membrane material connecting ring G1, the connecting ring 4 is welded to the end of the core 2 near the opening. The membrane material G and the connecting ring 4 are fixedly connected through the membrane material connecting ring G1.

[0085] To better illustrate the automatic detachment device for a large-span roof membrane structure under strong wind conditions (hereinafter referred to as the automatic detachment device) invented in this application, an ideal model is established to analyze the load-bearing capacity of the automatic detachment device. Specifically, it is assumed that the clamping plate 1, the core 2, and the fixing component 3 are all made of 4mm thick Q460 steel, the size of the clamping plate 1 is 100×100mm, the top edge width of the core 2 is 20mm, and the bottom edge width is determined according to the height h of the core 2 and the first acute angle α.

[0086] For ease of description, the naming convention for the automatic detachment device is specified. The pull-out bearing capacity of the device is mainly related to the pull-out depth (height h of the core 2) and the size of the included angle (first acute angle α) of the embedded clamping plate 1 in the core 2. Therefore, the model of the device is represented by the tangent value of the height h of the core 2 and the first acute angle α. For example, the device model H40A30 indicates that the height h of the core 2 is 40mm and the tangent value of the first acute angle α, tanα, is 1 / 30.

[0087] In the calculations, the following assumptions were made based on the structure of the automatic detachment device: the function of the fixing component 3 in the automatic detachment device is to prevent out-of-plane displacement of the core 2, and it does not participate in bearing the load; therefore, it is not considered in the modeling and calculation. During the numerical analysis, surface-to-surface contact was used to simulate the contact relationship between the clamping plate 1 and the core 2. The tangential behavior was set as penalized friction behavior with a friction coefficient of 0.15, and the normal behavior was hard contact. Thirty-five calculation models with different first acute angle α and pull-out depths were established using ABAQUS, as shown in Table 1.

[0088] Table 1. Model Correspondence of Automatic Membrane Material Removal Devices

[0089]

[0090]

[0091] During the calculation and analysis, the bottom of clamping plate 1 is completely fixed (simulating the case where clamping plate 1 is fixed to the steel structure members). A reference point is added at the center of the top edge of clamping core 2, and coupled with clamping core 2, a linearly increasing vertical displacement is applied (simulating the case where clamping core 2 is fixed to the membrane material and subjected to wind load), until clamping core 2 is pulled out and separated from clamping plate 1. The set value is equivalent to the maximum bearing capacity, and the maximum bearing capacity of different models of devices is shown in Table 2.

[0092] Table 2 Maximum load-bearing capacity of different models of equipment (unit: N)

[0093]

[0094] Since the load-bearing capacity of the device is significantly reduced when the tangent value tanα of the first acute angle α is greater than 1 / 20, the attached figure only shows the load-bearing capacity curve when the tangent value tanα is not greater than 1 / 20. Figures 5a to 5c For different device load-bearing capacity curves at the first acute angle α, Figures 6a to 6d The bearing capacity curves are for devices with different pull-out depths (height h of core 2). When the automatic detachment device fails (clamp 1 and core 2 separate due to plastic deformation), taking H20A4 and H20A5 as examples, the stress cloud diagrams are as follows: Figures 7a to 7b As shown, the deformation is as follows Figures 8a to 8d As shown.

[0095] From Table 2, Figures 5a to 8dIt can be seen that the load-displacement curve exhibits a parabolic shape. In the initial stage of the external load, as the displacement of the apex of the core 2 increases, the corresponding pull-out force also increases sharply, and the lateral deformation perpendicular to the pull-out direction of the clamping plate 1 also continuously increases, resulting in a flat segment on the load-displacement curve. Subsequently, as the load continues to increase, the lateral deformation continues to increase, and the stress also continuously increases. The stress in a large area around the groove 11 approaches the yield strength, and the load reaches its peak value. Afterward, as the core 2 continues to be pulled away, the compressive force gradually decreases, and the friction between the core 2 and the clamping plate 1 also decreases as the compressive force decreases. The load decreases as the displacement increases, and the curve shows a descending segment. In addition, the larger the tangent value of the first acute angle α (tanα), the greater the peak bearing capacity of the device. When the first acute angle α is the same, the pull-out depth has a relatively small impact on the peak bearing capacity of the automatic detachment device; when the pull-out depth is the same, the change in the first acute angle α has a significant impact on the peak bearing capacity of the device.

[0096] According to Table 2, the peak load-bearing capacity of the automatic detachment device is plotted on... Figure 9 .Depend on Figure 9 It can be seen that, under the same pull-out depth, the change of the first acute angle α has a significant impact on the peak bearing capacity, and the overall trend is upward. When the first acute angle α is 14.036° (tanα=1 / 4), the bearing capacity of different models of devices is about 20 times that of the corresponding devices when it is 1.46° (tanα=1 / 50).

[0097] As the first acute angle α increases, the ultimate bearing capacity of the H30 device is the greatest. This is mainly because the H30 device can more fully utilize the pull-out depth to enhance the bearing capacity. However, for the H40, H50, and H60 devices, the larger the pull-out depth and the first acute angle α, the longer the bottom edge of the core 2, and the shorter the reserved space on both sides of the clamping plate 1. During the calculation process, the weak parts on both sides of the clamping plate 1 fail rapidly, resulting in a lower bearing capacity than the H30 device. Therefore, the height of the core 2 is preferably 20mm-40mm, and the peak bearing capacity of the automatic detachment device can be controlled by changing the first acute angle α.

[0098] Through data fitting, the relationship between peak bearing capacity and the first acute angle α and pull-out depth is as follows:

[0099] f = 2116α 1.14112 β -0.14342

[0100] (Where: f is the peak load-bearing capacity of the automatic membrane detachment device, in Newtons; α is the first acute angle, in degrees; β is the ratio of the width of the top edge of the core 2 to the height of the core 2.)

[0101] To further illustrate the effectiveness of the automatic detachment device in practical applications, a specific project is used as an example to provide the basis for determining the model of the automatic detachment device. Through comparative analysis of the selected project case, the changes in the stress on the main roof components before and after the membrane material detaches are demonstrated. The project selected for numerical simulation is a steel structure roof of an entertainment plaza. The overall shape is an ellipsoidal shell with a left-right projection axis dimension of 114m, a front-back projection axis dimension of 104m, and a front cantilever span of 38.5m. The steel structure roof is completely detached from the underlying concrete structure and designed separately. The roof has no enclosing structure on all four sides, and the top height is 31.5m.

[0102] To ensure the membrane material does not detach during normal use and avoid unnecessary economic losses, the wind load is appropriately amplified. The basic wind pressure is considered based on a 100-year return period, the ground roughness is classified as Class B, and considering the unusual shape of the roof structure, a wind load sensitivity amplification factor of 1.1 is taken as 0.385 kN / m. 2 .

[0103] According to the "Code for Design of Building Structures" (GB50009-2012), the surface pressure of the building envelope is calculated using the following formula:

[0104] ω k =β gz μ z μ st ω0

[0105] (where: ω) k —Standard value of wind load, ω0—Basic wind pressure, β gz Let μ be the gust coefficient at height z. z μ is the coefficient of wind pressure height variation. st (This represents the local wind pressure shape coefficient.)

[0106] Based on the definitions of the standard values ​​of wind pressure for the building envelope and the main structure, the average wind pressure coefficient, root mean square coefficient, maximum wind pressure coefficient, and minimum wind pressure coefficient obtained from the wind tunnel test are converted to a height of 10m to obtain the wind suction β of the roof structure in all wind directions. gz μ z μ st Envelope diagram, such as Figure 10 As shown.

[0107] Depend on Figure 10 The distribution of wind load on the steel roof can be determined. Combined with the lateral spacing of the devices and the width of a single longitudinal frame of the roof, the standard load on the automatic detachment device connected to the membrane at any point can be obtained. This standard load is then converted to a design value and multiplied by an amplification factor (temporarily taken as 2.0 in this paper; however, the ratio of the strong wind load during roof collapse to the design value can also be used) to determine the device model. Specifically, the device model can be determined using β... gz μz μ st The load capacity is divided into different ranges, and device models with peak load capacity greater than the maximum value of the range are selected to ensure that the membrane material can work normally. In the event of extreme weather, the automatic detachment device can ensure that the membrane material can detach. Table 3 lists the device models selected for different load ranges.

[0108] Table 3. Correspondence Table for Device Model Selection

[0109]

[0110] When a membrane structure is subjected to wind loads exceeding a certain critical level, its automatic detachment mechanism will activate, causing the roof membrane to detach. The degree of unloading of the main load-bearing components varies depending on the area of ​​detachment. The detachment rate is defined as the ratio of the area of ​​the steel structure roof not subjected to wind loads to the total area of ​​the roof, expressed as:

[0111] ρ=(A-Aw) / A

[0112] (Where: ρ is the roof membrane shedding rate; A is the total area of ​​the roof surface; Aw is the area of ​​the roof surface subjected to wind load.)

[0113] To address the load conditions on the steel structure, five roof models with different detachment rates were established by varying the area of ​​the roof affected by wind loads. These models simulated roof structures with complete, partial, and no membrane detachment. For the sake of simplicity, the effects of different membrane detachment areas and changes in wind pressure on the roof surface after local membrane detachment were not considered.

[0114] Under design load conditions, the allowable stress of the roof members shall be 0.85 of the full stress, that is, the maximum value of the ratio of actual stress to allowable stress shall be 0.85. The deflection shall meet the requirements of the following deflection calculation formula:

[0115] [L1]≤L1 / 250=456mm

[0116] [L2]≤L2 / 125=308mm

[0117] (Where: [L1] is the mid-span deflection limit of the roof; L1 is the span of the left and right projected axes; [L2] is the deflection limit of the cantilever end of the roof; L2 is the span of the cantilever end of the roof.)

[0118] When the membrane does not detach (ρ = 0%), wind load is applied to the entire roof surface to simulate the state where the membrane material does not detach. The relevant parameters for wind load on the roof surface are calculated based on wind tunnel test results. Under the combined action of 1.3 times the dead load and 1.5 times the wind load, the axial force, stress ratio, and displacement of the members are as follows: Figures 11a to 11cAs shown, the maximum axial force of the roof members is 2613 kN (compression), the stress ratio of the members is 0.741, and the stress of the members under design conditions is less than the limit of 0.85. The maximum displacement of the roof occurs at the cantilevered position at the front end of the roof, and its value is 280.338 mm, which is less than the deflection limit calculated according to the aforementioned deflection calculation formula. Under design conditions, all indicators meet the design requirements.

[0119] When a partial membrane detachment occurs (ρ = 25%), wind load acts on most of the roof surface, simulating a partial membrane detachment. The area affected by the wind load is as follows: Figure 12 As shown, the area where the membrane material detached is located on one side of the support (one side of the support is...). Figure 12 The support side shown is E), that is, the non-cantilever side (the cantilever side is...). Figure 12 For the cantilever side (F), the partial factors for dead load and wind load remain unchanged. The calculation results for the internal forces, stress ratios, and deflections of the roof members are as follows: Figures 13a to 13c As shown, the maximum internal force of the members is 2588 kN (compression), the maximum stress ratio of the members is 0.741, and the maximum deflection of the roof is 270.701 mm. Compared with the case where the membrane does not detach, the maximum internal force and displacement are reduced to some extent. The maximum member stress is not significantly reduced, but the number of members with a stress ratio greater than 0.45 decreases, and the number of members with a stress ratio less than 0.15 increases, thus improving the structural stress performance.

[0120] When the detachment rate remains constant, and the detachment area is located on the other side of the cantilever, under this condition, the maximum internal force of the members decreases to 1936kN, the maximum roof deflection is 196.425mm, the maximum stress ratio of the members is 0.687, and the number of members with a stress ratio greater than 0.45 decreases to 2.73%. It can be seen that the effect of membrane material detachment in different areas on the load effect of the structure is different. In practical applications, automatic detachment devices can be installed in stress-sensitive areas.

[0121] When the membrane experiences partial detachment (ρ = 50%), wind load is applied to half of the roof surface, simulating half of the membrane detaching. The area affected by the wind load is as follows: Figure 14 As shown, the load combination is the same as described above, and the calculation results are as follows. Figures 15a to 15c As shown, the maximum internal force of the roof members is 2505 kN (compression), the maximum stress ratio is 0.708, and the maximum deflection of the roof is 258.848 mm. When the actual detachment area is half, the maximum internal force, displacement, and stress of the members decrease significantly compared to the condition where the membrane does not detach. The number of members with a stress ratio greater than 0.45 decreases to 3.86%, which is basically equivalent to 50% of the condition where the membrane does not detach. The larger the detachment area, the more obvious the unloading.

[0122] When the detachment rate remains constant and the detachment area is on the other side, the maximum stress of the member is 0.571. The number of members with a stress ratio greater than 0.6 decreases to 0%, the number of members with a stress ratio between 0.45 and 0.6 decreases to 0.44%, and the number of members with a stress ratio less than 0.15 increases to 60.94%. Figure 15c Compared to the previous method, the improvement in load-bearing performance is more obvious, indicating that finding the sensitive unloading area of ​​the structure is the key to installing an automatic detachment device.

[0123] When a partial membrane detachment occurs (ρ = 75%), wind load is applied to the local roof surface, simulating a partial membrane detachment. The detachment area further increases towards the cantilever end, and the area affected by the wind load on the roof is as follows: Figure 16 As shown, the partial factors are selected in the same way as before, and the calculation results are as follows. Figures 17a to 17c As shown, the maximum internal force of the roof members is 2165 kN (compression), the maximum stress ratio of the members is 0.670, and the maximum deflection of the roof occurs at the cantilever end, with a maximum value of 248.109 mm. It can be seen that as the detachment area increases, the internal force of the roof members further decreases, and the number of members with high stress ratios also further decreases.

[0124] When the membrane has completely detached (ρ = 100%), the wind load has been unloaded and has little impact on the main roof structure. Therefore, the wind load effect is not considered in the calculation; only the roof dead load is taken into account. The calculation results are as follows: Figures 18a to 18c As shown, the maximum internal force of the roof members is 1565 kN (compression), the maximum stress ratio is 0.442, and the maximum deflection is 167.300 mm. Compared with the case where the membrane material does not detach, the maximum internal force, stress ratio, and deflection of the members when the membrane material completely detaches are 59.9%, 59.7%, and 59.6% of those when the membrane material does not detach, respectively, indicating a significant improvement in the safety redundancy of the members.

[0125] In practical applications, designers can determine the stress-sensitive areas based on the roof shape to identify the installation areas for the automatic detachment device. The simulation results clearly show that membrane detachment is an effective measure to ensure the safety and reliability of the roof structure under extreme wind conditions. Therefore, for steel structure roofs using automatic detachment devices, the automatic detachment of the membrane under strong winds effectively reduces the load effect on the structural members, preventing damage to the roof members or overall structural collapse caused by deformation of the steel structure members, thus ensuring the safety and reliability of large-span steel structures with membrane installations under extreme wind conditions.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automatic detachment device for a large-span roof membrane structure under strong wind conditions, characterized in that, include: The sandwich panel (1) and the core (2); The clamp (1) is provided with an upward-opening groove (11), the cross-section of the groove (11) is trapezoidal, the opening of the groove (11) is located on the top edge of the trapezoid, the width of the opening is the same as the length of the top edge, and the end of the clamp (1) away from the opening is provided with an installation part that is fixedly connected to the roof steel structure. The core (2) is a block-shaped body whose outer contour is adapted to the groove (11). The core (2) is embedded in the groove (11). The end of the core (2) near the opening is provided with a connecting part that is fixedly connected to the roof membrane material. When the tension in the vertical direction of the core (2) is greater than the set value, the clamping plate (1) and the core (2) undergo plastic deformation and separate.

2. The automatic detachment device for a large-span roof membrane structure under strong winds as described in claim 1, characterized in that, The trapezoid is an isosceles trapezoid, and the angle between the leg and the height of the isosceles trapezoid is a first acute angle. The opening of the first acute angle faces the base of the isosceles trapezoid, and the tangent of the first acute angle ranges from 0.02 to 0.

25.

3. The automatic detachment device for a large-span roof membrane structure under strong winds according to claim 2, characterized in that, The height of the isosceles trapezoid is 20-60mm, and the length of the top side of the isosceles trapezoid is 20mm.

4. The automatic detachment device for a large-span roof membrane structure under strong winds according to claim 3, characterized in that, The length of the groove (11) is 4-10 mm.

5. The automatic detachment device for a large-span roof membrane structure under strong winds according to claim 4, characterized in that, The length of the groove (11) is 4 mm.

6. The automatic detachment device for a large-span roof membrane structure under strong winds according to claim 1, characterized in that, It also includes an end baffle (3), which is fixed to the clamp (1) by threaded fasteners; The groove (11) extends through the clamping plate (1) along the thickness direction, and the end baffle (3) is provided on both sides of the clamping plate (1) to prevent the core (2) from coming out of the groove (11) along the thickness direction of the clamping plate (1).

7. The automatic detachment device for a large-span roof membrane structure under strong winds according to claim 1, characterized in that, The mounting part is a connecting bolt (5), and the end of the clamp (1) away from the opening is fixedly connected to the head of the connecting bolt (5).

8. The automatic detachment device for a large-span roof membrane structure under strong winds according to claim 1, characterized in that, The connecting part is a connecting ring (4), and the end of the core (2) near the opening is fixedly connected to the connecting ring (4).

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