A method and system for judging continuous collapse risk of a cable dome structure

Abstract

The application discloses a kind of cable dome structure continuous collapse risk judgment method and system.The method includes (1) load initial cable dome structure model, calculate the importance coefficient of bar, judge the continuous collapse risk category of removing the bar;(2) bar is sorted after importance coefficient normalization, search adjacent and continuous collapse risk category different bar;(3) adjust the cable dome structure model, so that the importance coefficient of bar changes in the value range of bar classification critical point, and judge the continuous collapse risk category of the bar, search the bar importance coefficient value that just can make bar classification result different as bar classification critical point;(4) judge continuous collapse risk category.The application determines the importance coefficient of each component in the process of resisting continuous collapse as the decisive factor of continuous collapse risk, to reduce its continuous collapse risk as far as possible with smaller calculation cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of civil engineering, and more particularly, relates to a method and system for judging the progressive collapse risk of a cable dome structure. BACKGROUND

[0002] A cable dome structure is a flexible structural system formed by cables and compression bars as basic units through tensioning. Due to the full use of the high strength of the cables and the optimization of the structural stiffness distribution by adjusting the structural prestress distribution, the structure has good bearing performance, strong spanning capacity, light structure and many other advantages, and is widely used in practical engineering.

[0003] At the same time, due to the low redundancy of such structures, when subjected to sudden conditions such as wind overload, explosion impact and other unexpected disturbances, continuous collapse is easy to occur. Therefore, it is of great significance to further analyze the anti-continuous collapse performance of such structures and improve the ability of the structure to resist continuous collapse and not to cause disproportionate damage for further application.

[0004] The current research object of structural progressive collapse mainly focuses on frame structure system, and the research on spatial large-span structure is relatively less. The main reason is that based on the general understanding that the traditional spatial large-span structure such as net rack and shell has a high number of static indeterminacy, it is believed that the failure of a single rod is not enough to significantly weaken the bearing capacity reserve of the overall structure. However, the cable dome structure is different from the traditional large-span structure with high-order statically indeterminate components such as net rack and shell. It has low redundancy and is sensitive to construction errors and other unexpected disturbances, and is easy to collapse under overload or unexpected disturbance. Therefore, it is necessary to further carry out the analysis of the progressive collapse mechanism in accordance with the characteristics of the cable dome structure, evaluate the role of various rods in resisting the continuous collapse of the structure, and carry out the optimization design research based on the anti-continuous collapse of the structure. Scholars such as Fan Feng at home and abroad use techniques such as life and death unit, instantaneous removal of components, and instantaneous loading method to simulate broken cables and analyze the changes of structural rod internal forces and node displacement responses after local failure and cable breakage of various cable dome structures. Based on ANSYS / LS-DYNA software, Lu Jinyu, Jiang Xiaofeng and others analyzed the dynamic response and collapse process of structures such as cable-strut tension structure and beam string structure after local failure or cable breakage. In general, the analysis of internal force, displacement and other responses and the study of collapse phenomenon caused by local failure and cable breakage of tension structure have gradually developed, but more based on the qualitative description of cable slackness, local large deformation and large displacement, and the collapse development mechanism has not been analyzed in depth. SUMMARY

[0005] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a method for judging the progressive collapse risk of cable dome structures. The purpose is to determine the progressive collapse risk category of various members in the cable dome structure model by using the member importance coefficient, so as to quickly and accurately optimize the cable dome structure and minimize its progressive collapse risk. This solves the technical problem that the existing technology cannot quickly and accurately judge the progressive collapse risk of cable dome structures.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for assessing the risk of progressive collapse of a cable-stayed dome structure is provided, comprising the following steps:

[0007] (1) Load the initial cable dome structure model, calculate the importance coefficient of each type of member, and determine the continuous collapse risk category of removing the member according to the continuous collapse area and vertical node displacement after removing a member.

[0008] (2) After normalizing the importance coefficient of the members obtained in step (1), sort them and search for one or more groups of adjacent members with different collapse risk categories.

[0009] (3) For at least one group of adjacent members with different continuous collapse risk categories obtained in step (2), the values ​​of their member importance coefficients are respectively used as the upper and lower limits of the value range of the member classification critical point; the cable dome structure model is adjusted so that the member importance coefficient of at least one member in the group changes within the value range of the member classification critical point, and the continuous collapse risk category of the member is determined according to the continuous collapse area and vertical node displacement after removing the member, and the member importance coefficient value that makes the member classification results different is searched as the member classification critical point;

[0010] (4) For the cable dome structure model, calculate the importance coefficient of the target members. According to the principle that the more important the member is, the greater its risk of continuous collapse, the member classification critical point obtained in step (3) is used to determine its continuous collapse risk category.

[0011] Preferably, in the method for judging the risk of progressive collapse of the cable dome structure, step (1) of the cable dome structure model includes the topology of each member of the cable dome, the cross-sectional area parameters of each member, and the prestress parameters of each member.

[0012] Preferably, in the method for assessing the progressive collapse risk of the cable dome structure, the member importance coefficient γ of member j is... j Calculate as follows:

[0013] γ j =δ j / d j

[0014] wherein δ j is the sum of squares of displacement differences of all nodes of the cable dome structure before and after removal of a certain bar j, d j is the cumulative displacement of all nodes of the cable dome structure before removal of a certain bar j, and is calculated as follows:

[0015]

[0016] wherein, are displacement differences of the i-th node in x, y, z directions before and after removal of a certain bar j, and are calculated as follows:

[0017]

[0018]

[0019]

[0020] n is the total number of nodes of the structure;(u j ) ix ,(u j ) iy ,(u j ) iz and (u j )'(u ix )'(u j )'(u iy )'(u j )'(u iz ) are displacement components of the i-th node of the structure in x, y, z directions before and after removal of a certain bar j.

[0021] Preferably, the cable dome structure progressive collapse risk judgment method normalizes the bar importance coefficient, and the normalized bar importance coefficient γ j′ is calculated as follows:

[0022] γ j′ = γ j / ∑ j＝1 γ j .

[0023] Preferably, the cable dome structure progressive collapse risk judgment method divides the progressive collapse risk category according to the following standards:

[0024] When the progressive collapse area of the cable dome structure satisfies the first condition, it is determined that the cable dome has progressive collapse failure, and the bar is judged as the key component with the highest progressive collapse risk; the first condition is preferably that the maximum vertical node displacement of the cable dome is greater than 1 / 50 of the span and the failure area reaches 30% of the total plane area of the structure;

[0025] When the continuous collapse area of the cable dome structure satisfies the second condition, it is determined that the cable dome has local continuous collapse failure, and the rod member is determined to be an important component with high continuous collapse risk; the second condition is preferably that the maximum vertical node displacement of the cable dome is greater than 1 / 50 of the span, but the failure area does not reach 30% of the total plane area of the structure,

[0026] When the maximum vertical node displacement of the cable dome is less than 1 / 50 of the span, or when the maximum node displacement of the cable dome is greater than 1 / 50 of the span, but the failure area does not reach 15% of the total plane area of the structure, it is determined that the cable dome has not occurred continuous collapse failure, and the rod member is determined to be a common component with low continuous collapse risk.

[0027] Preferably, the continuous collapse risk judgment method of the cable dome structure, step (2) is specifically:

[0028] Take the common rod member with the largest rod member importance coefficient and the important component with the smallest rod member importance coefficient as the first group of adjacent rod members with different continuous collapse risk categories; take the important rod member with the largest rod member importance coefficient and the key component with the smallest rod member importance coefficient as the second group of adjacent rod members with different continuous collapse risk categories.

[0029] Preferably, the continuous collapse risk judgment method of the cable dome structure, step (3) adjusts the cable dome structure model, including adjusting the cross-sectional area of the rod member, adjusting the length of the rod member, adjusting the prestress level of the cable dome structure, and adjusting the radius of the ring cable of the cable dome structure.

[0030] Preferably, the continuous collapse risk judgment method of the cable dome structure, step (3) adjusts the cable dome structure model, which is specifically:

[0031] Calculate the influence law of each design parameter of the cable dome structure model on each rod member importance coefficient, and adjust each design parameter according to the influence law of the rod member importance coefficient in the order of increasing or decreasing influence degree; the design parameters of the cable dome structure model include rod member cross-sectional area, rod member length, prestress level, and ring cable radius.

[0032] Preferably, the continuous collapse risk judgment method of the cable dome structure, step (3) searches for the rod member importance coefficient value that can make the rod member classification results different as the rod member classification critical point, which is specifically:

[0033] selecting one of the one or more groups of adjacent and different progressive collapse risk category bars as a reference bar, adjusting the cable dome structure model according to the ascending or descending order of the bar importance coefficients, and changing the bar importance coefficient of the reference bar within the bar classification critical point value range, and judging the progressive collapse risk category of the reference bar according to the continuous collapse area and vertical joint displacement after removing the reference bar, and reducing the adjustment range and reversely adjusting the bar importance coefficient of the reference bar whenever the risk category of the reference bar changes, and determining the bar classification critical point value range when the difference between the bar importance coefficients of the reference bar at the time of two adjacent changes of the progressive collapse risk category of the reference bar is less than a preset difference threshold.

[0034] According to another aspect of the present application, a progressive collapse risk judgment system for a cable dome structure is provided, which comprises a model loading module, a bar searching module, a bar classification critical point searching module, and a progressive collapse risk judgment module.

[0035] The model loading module is configured to load an initial cable dome structure model, calculate the bar importance coefficient of each type of bar, and judge the progressive collapse risk category of a bar after removing the bar according to the continuous collapse area and vertical joint displacement after removing the bar, and submit the bar importance coefficient and the progressive collapse risk category of the bar to the bar searching module.

[0036] The bar searching module is configured to sort the bars according to the normalized bar importance coefficients, search one or more groups of adjacent and different progressive collapse risk category bars, and submit the one or more groups of bars and their importance coefficients to the bar classification critical point searching module.

[0037] The bar classification critical point searching module is configured to take the values of the bar importance coefficients of the at least one group of adjacent and different progressive collapse risk category bars obtained in step (2) as the upper and lower limits of the bar classification critical point value range, adjust the cable dome structure model so that the bar importance coefficient of at least one bar in the group changes within the bar classification critical point value range, and judge the progressive collapse risk category of the bar according to the continuous collapse area and vertical joint displacement after removing the bar, search for a bar importance coefficient value that can change the bar classification result and serve as a bar classification critical point, and submit the bar classification critical point to the progressive collapse risk judgment module.

[0038] The continuous collapse risk judgment module is configured to calculate a bar importance coefficient of the target bar of the cable dome structure model, and judge a continuous collapse risk category of the target bar according to the principle that the more important the bar importance is, the greater the continuous collapse risk is.

[0039] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0040] The present application determines the failure mode and collapse mechanism, determines the importance coefficient of various components in the process of resisting continuous collapse as a decisive factor of the continuous collapse risk, and determines the influence law of the bar section, structure shape and other design parameters on the importance coefficient, thereby determining the influence law of the bar section, structure shape and other design parameters on the structure resisting continuous collapse, improving the ability of the cable dome structure to resist continuous collapse, and assisting in optimizing the cable dome structure design model. On the one hand, the present application determines the influence law of the bar section, structure shape and other design parameters on the structure resisting continuous collapse, thereby providing an optimization direction for the cable dome structure design model, thereby reducing the calculation amount, and on the other hand, it is not necessary to repeatedly simulate the continuous collapse process of the cable dome structure to calculate the continuous collapse area after removing the bar in the optimization process, so as to judge the continuous collapse type. Therefore, in general, the present application realizes optimization for the continuous collapse risk with a small calculation cost, and reduces the continuous collapse risk of the cable dome structure as much as possible. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a schematic diagram of the initial cable dome structure model topology of the embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0043] The present application finds that the bar importance coefficient is a decisive factor of the continuous collapse risk of the cable dome structure, and the continuous collapse risk of the cable dome structure caused by removing various components can be judged by evaluating the importance coefficient of various bars.

[0044] The cable dome structure continuous collapse risk judgment method provided by the present application comprises the following steps:

[0045] (1) loading an initial cable dome structure model, calculating a bar importance coefficient of each type of bar, and judging a continuous collapse risk category of removing a bar according to a continuous collapse area and a vertical node displacement after removing the bar;

[0046] The cable dome structure model comprises a cable dome bar topology structure, a cross-sectional area parameter of each component, and a prestress parameter of each component.

[0047] The bar importance coefficient γ of the bar j j is calculated according to the following method:

[0048] γ j = δ j / d j

[0049] Wherein, δ j is the sum of squares of displacement differences of all nodes of the cable dome structure before and after removing a bar j, and d j is the displacement of all nodes of the cable dome structure before removing a bar j, which is calculated according to the following method:

[0050]

[0051] Wherein, are displacement differences of the i-th node in x, y and z directions before and after removing a bar j, which are calculated according to the following method:

[0052]

[0053]

[0054]

[0055] n is the total number of structure nodes;(u j ) ix , (u j ) iy , (u j ) iz and (u j )'' ix , (u j )'' iy , (u j )'' iz are displacement components of the i-th node of the structure in x, y and z directions before and after removing a bar j.

[0056] Preferably, the bar importance coefficient is normalized, and the normalized bar importance coefficient γ j′ is calculated according to the following method:

[0057] γj′ = γ j / ∑ j＝1 γ j .

[0058] The continuous collapse area is the horizontal projection area of the area surrounded by the failed rod; the vertical node displacement is the vertical displacement of each node under the action of the load, which can be calculated by finite element analysis.

[0059] The continuous collapse risk category is divided according to the following standards:

[0060] When the continuous collapse area of the cable dome structure satisfies the first condition, it is determined that the cable dome has continuous collapse failure, and the rod is judged to be the key component with the highest continuous collapse risk; the first condition is preferably that the maximum vertical node displacement of the cable dome is greater than 1 / 50 of the span and the failure area reaches 30% of the total plane area of the structure;

[0061] When the continuous collapse area of the cable dome structure satisfies the second condition, it is determined that the cable dome has local continuous collapse failure, and the rod is judged to be an important component with a relatively high continuous collapse risk; the second condition is preferably that the maximum vertical node displacement of the cable dome is greater than 1 / 50 of the span, but the failure area does not reach 30% of the total plane area of the structure,

[0062] When the maximum vertical node displacement of the cable dome is less than 1 / 50 of the span, or when the maximum node displacement of the cable dome is greater than 1 / 50 of the span, but the failure area does not reach 15% of the total plane area of the structure, it is determined that the cable dome does not have continuous collapse failure, and the rod is judged to be a common component with a relatively low continuous collapse risk.

[0063] (2) The rod is sorted after normalizing the rod importance coefficient obtained in step (1), and one or more groups of adjacent and continuous collapse risk category different rods are searched; specifically:

[0064] Take the common rod with the largest rod importance coefficient and the important component with the smallest rod importance coefficient as the first group of adjacent and continuous collapse risk category different rods; take the important rod with the largest rod importance coefficient and the key component with the smallest rod importance coefficient as the second group of adjacent and continuous collapse risk category different rods.

[0065] (3) for at least one group of adjacent and continuous bar members with different collapse risk categories obtained in step (2), taking the value of the bar member importance coefficient of each bar member in the group as the upper and lower limits of the value range of the bar member classification critical point; adjusting the cable dome structure model so that the bar member importance coefficient of at least one bar member in the group changes within the value range of the bar member classification critical point, and judging the continuous collapse risk category of the bar member according to the continuous collapse area and vertical node displacement after removing the bar member, searching for the bar member importance coefficient value that can just make the bar member classification result different as the bar member classification critical point;

[0066] The adjustment of the cable dome structure model preferably includes adjusting the cross-sectional area of the bar member, adjusting the length of the bar member, adjusting the prestress level of the cable dome structure, and adjusting the radius of the ring cable of the cable dome structure. Specifically:

[0067] The influence of each design parameter of the cable dome structure model on the bar member importance coefficient is calculated and analyzed, and each design parameter is adjusted according to its influence on the bar member importance coefficient in ascending or descending order. The design parameters of the cable dome structure model include the cross-sectional area of the bar member, the length of the bar member, the prestress level, and the radius of the ring cable.

[0068] The cross-sectional area of the bar member, the length of the bar member, the prestress level of the cable dome structure, and the radius of the ring cable of the cable dome structure model, etc. The influence of the parameters of the model on the importance coefficient of a specific category of bar members can be determined, which may be positively correlated, negatively correlated, or positively correlated within a certain range and negatively correlated within a certain range. Therefore, for a specific model, the importance coefficient of a specific bar member can be reduced by following the influence of the parameters of the cable dome structure model on the specific bar member, thereby optimizing the cable dome structure and reducing the risk of continuous collapse.

[0069] The search for the bar member importance coefficient value that can just make the bar member classification result different as the bar member classification critical point is specifically:

[0070] selecting one of the group of adjacent and continuous collapse risk category different bars as a reference bar, so that the bar importance coefficient adjusts the cable dome structure model in ascending or descending order, and the bar importance coefficient of the reference bar changes within the range of the bar classification critical point, and the continuous collapse risk category of the reference bar is judged according to the continuous collapse area and the vertical node displacement after removing the bar, and the bar importance coefficient of the reference bar is adjusted in the opposite direction when the risk category of the bar changes, and the adjustment range is reduced, until the difference between the bar importance coefficients of the reference bar at the time of the adjacent continuous collapse risk category change of the reference bar is less than the preset difference threshold, and the bar classification critical point of the risk category change is determined between the bar importance coefficients of the reference bar at the time of the adjacent continuous collapse risk category change of the reference bar.

[0071] (4) For the cable dome structure model, the bar importance coefficient of the target bar is calculated, and the bar classification critical point obtained in step (3) is used to judge the continuous collapse risk category according to the principle that the more important the bar importance, the greater the continuous collapse risk.

[0072] The following is an example:

[0073] A cable dome structure continuous collapse risk judgment method, taking the roof of the Inner Mongolia Yiqi National Fitness Sports Center as the judgment object, comprising the following steps:

[0074] (1) Load the initial cable dome structure model, calculate the bar importance coefficient of each type of bar, and judge the continuous collapse risk category of the bar according to the continuous collapse area and the vertical node displacement after removing a certain bar;

[0075] The cable dome structure model includes the topology of each bar of the cable dome, the cross-sectional area parameters of each component, and the prestress parameters of each component. Specifically:

[0076] The roof of the Inner Mongolia Yiqi National Fitness Sports Center adopts a flexible cable-strut tension structure, a rib-ring type cable dome structure, with a span of 71.2 meters, a rise of 5.5 meters, a rise-span ratio of about 1 / 13, 20 equal divisions in the ring direction, and a design load of 0.4 kN / m2. The structure is provided with two ring cables, a tension ring in the center, and the entire structure is fixed and hinged on the peripheral rigid compression ring beam. The structure model, plane and section are shown in Figure 1 , wherein Figure 1 (a) is a structure model, Figure 1 (b) is a structure plane, Figure 1 (c) is a structure section and size diagram, and the cross-sectional parameters and initial prestress of each component are shown in Table 1, wherein the elastic modulus of the cable and the compression bar is 160 GPa and 206 GPa respectively.

[0077] Table 1 Parameters and initial pre-stress ofinitial model elements

[0078] Table 1 Parameters and initial pre-stress ofinitial model elements

[0079]

[0080] Analysis method:

[0081] Selection and modeling of elements: LINK167 and LINK160 elements are selected respectively based on the stress characteristics of cable and bar elements in cable-strut pre-tensioned structures, and pre-stress is applied by defining offset. The specific formula is as follows:

[0082] F = K x max{AL, 0.0}

[0083] K = EA / (L0-offset)

[0084] Wherein AL and L0 are the length change and initial length of the bar, E and A are the elastic modulus and cross-sectional area of the bar, and offset is the offset. For LINK160 element, a bilinear dynamic material model is adopted, and the failure strain of the element is defined as 0.01, that is, if the strain of the compression bar exceeds 0.01 during the analysis process, the bar is automatically removed from the structure.

[0085] Replacement and unloading of equivalent force: In order to consider the influence of the initial state and eliminate the dynamic influence of the growth of static load on the structure, this paper adopts the full dynamic equivalent load instantaneous unloading method for analysis, that is, first remove a component in the structure, replace the component with equivalent force, and then unload the equivalent force, and then explore the dynamic response of the structure in the whole process of failure of the component. When the structure is replaced by equivalent force to remove the component, unload the equivalent force, etc. The replacement time, duration and unloading time of the equivalent force are generally taken as 2 times, 20 times and 1 / 10 times the natural period of the residual structure, respectively. The whole process of equivalent force action in this paper is shown in Table 2.

[0086] Table 2 Equivalent force schedule

[0087] Table 2 Equivalent force schedule

[0088]

[0089] For the 13 types of bars in the initial model, the bar importance coefficient of bar j is calculated as follows: j ​

[0090] γ j =δ j / d j

[0091] Where, δ j Let d be the sum of the squares of the displacement differences of all nodes of the cable dome structure before and after the removal of a certain member j. j The displacements of all nodes of the cable dome structure before the removal of a certain member j are calculated as follows:

[0092]

[0093] in, The displacement differences along the x, y, and z directions of the i-th node before and after removing a certain member j are calculated as follows:

[0094]

[0095]

[0096]

[0097] n is the total number of structural nodes; (u j ) ix 、(u j ) iy 、(u j ) iz and(u j )′ ix 、(u j )′ uy 、(u j )′ iz These are the displacement components of the i-th node along the x, y, and z directions before and after the removal of a certain member j.

[0098] Preferably, the importance coefficient of the member is normalized, and the normalized member importance coefficient γ j′ Calculate using the following method:

[0099] γ j′ =γ j / ∑ j＝1 γ j .

[0100] Analysis of the structural dynamic response and collapse mode after the removal of the member, taking the displacement response and collapse mode of the structure after the removal of the representative member—the external ridge cable—as an example (as shown in Table 3):

[0101] The categories of progressive collapse risks are classified according to standards:

[0102] The importance coefficients of various members are related to the member importance types and the structure collapse mode according to the progressive collapse criteria of the cable dome structure in the UFC4-023-03 standard. The results show that the member importance coefficient determines the structure collapse mode. (1) When the maximum vertical node displacement of the cable dome is greater than 1 / 50 of the span and the failure area reaches 30% of the total plane area of the structure, it is considered that the cable dome has occurred progressive collapse damage. (2) When the maximum vertical node displacement of the cable dome is greater than 1 / 50 of the span, but the failure area does not reach 30% of the total plane area of the structure, it is considered that the cable dome has occurred local progressive collapse damage. (3) When the maximum vertical node displacement of the cable dome is less than 1 / 50 of the span, or when the maximum node displacement of the cable dome is greater than 1 / 50 of the span, but the failure area does not reach 15% of the total plane area of the structure, it is considered that the cable dome has not occurred progressive collapse damage.

[0103] According to the standard, the collapse mode of the cable dome after removing the member is divided into three modes: progressive collapse, local progressive collapse, and non-progressive collapse. The corresponding removed members are defined as key members, important members, and ordinary members. The results are shown in Table 3.

[0104] Table 3 Analysis of collapse mode and member importance caused by removing different members

[0105] Table 3 Analysis of collapse mode and member importance caused by removing different members

[0106]

[0107]

[0108] (2) The members are sorted according to the member importance coefficients obtained in step (1), as shown in Table 3, and a group or multiple groups of adjacent and different progressive collapse risk category members are searched. Specifically:

[0109] The ordinary member with the largest member importance coefficient and the important member with the smallest member importance coefficient are taken as the first group of adjacent and different progressive collapse risk category members. The important member with the largest member importance coefficient and the key member with the smallest member importance coefficient are taken as the second group of adjacent and different progressive collapse risk category members.

[0110] This embodiment selects two groups of adjacent and different progressive collapse risk category members, namely:

[0111] The first group: the lower chord of the tension ring and the upper chord of the tension ring; the member importance sorting is adjacent, which is 10 and 11 respectively; the progressive collapse risk category is different, which is ordinary member and important member respectively;

[0112] The second group: the tension ring upper chord and the inner ring cable; the importance of the bars in the group is adjacent, and the importance of the bars is 11 and 12 respectively; the risk categories of continuous collapse are different, and the risk categories of continuous collapse are important components and key components respectively.

[0113] (3) for at least one group of bars obtained in step (2) adjacent and different in risk category of continuous collapse, the bar importance coefficient value of the group is respectively taken as the upper and lower limits of the bar classification critical point value range; adjust the cable dome structure model, so that the bar importance coefficient of at least one bar in the group changes in the bar classification critical point value range, and judge the risk category of continuous collapse of the bar according to the continuous collapse area and vertical node displacement after removing the bar, and search for the bar importance coefficient value which can make the bar classification result different as the bar classification critical point;

[0114] The adjustment of the cable dome structure model comprises adjusting the cross-sectional area of the bar, adjusting the length of the bar, adjusting the prestress level of the cable dome structure, and adjusting the radius of the ring cable of the cable dome structure.

[0115] In order to explore the influence of different parameters on the bar importance coefficient and the anti-continuous collapse performance of the structure, the present application further analyzes the structural response and collapse mode under the action of different prestress levels, component cross section, ring cable radius and compression rod length and other parameters.

[0116] 1, prestress level

[0117] Keeping other parameters of the structure unchanged, the prestress level is taken as 0.8 times, 1.2 times and 1.5 times of the initial prestress level respectively, the importance coefficient of each bar is calculated, and it can be found that: (1) different prestress levels have different influences on the importance coefficient of each bar, and the influence on the inner ring cable is the largest. When the prestress level increases from 0.8 times to 1.5 times of the initial prestress, the importance coefficient of the inner ring cable decreases from 0.24 to 0.1, which decreases by 13%, and the change range of the importance coefficient of other bars is not more than 10%. (2) Generally, the size of the prestress level has little effect on the anti-continuous collapse capacity of the structure.

[0118] 2, component cross section

[0119] Keeping other parameters of the structure unchanged, the sectional area of the component is taken as 0.8 times, 1.2 times and 1.5 times the initial sectional area respectively, and the importance coefficients of each rod are calculated, which can find that: (1) Different sectional areas of components have different influences on the importance coefficients of rods, among which the influence on the inner ring cable is the largest, and when the sectional area of the component increases from 0.8 times to 1.5 times the initial sectional area, the importance coefficient increases from 0.22 to 0.24, which increases by 9%, and the change range of the importance coefficients of other rods does not exceed 3%. (2) In general, the sectional area of the rod has little influence on the continuous collapse resistance of the structure.

[0120] 3, radius of the ring cable

[0121] Keeping other parameters of the structure unchanged, the radius of the outer ring cable is taken as 0.8 times and 1.2 times the initial radius of the outer ring cable respectively, and the importance coefficients of each rod are calculated, which can find that: (1) The change of the radius of the outer ring cable has different influences on the importance coefficients of various rods, among which the influence on the upper chord of the tension ring is the largest, and when the radius of the outer ring cable increases from 0.8 times to 1.2 times, the importance coefficient of the upper chord of the tension ring increases from 0.13 to 0.16, which increases by 23%, and the importance coefficient of the inner ring cable decreases from 0.25 to 0.22, which decreases by 12%. The change range of the importance coefficients of other rods does not exceed 4%. (2) In general, the size of the radius of the outer ring cable has little influence on the continuous collapse resistance of the structure. (3) At the same time, it is found that the radius of the inner ring cable has little influence on the continuous collapse resistance of the structure.

[0122] 4, length of the compression rod

[0123] Keeping other parameters of the structure unchanged, the length of the outer compression rod is adjusted to be 0.8 times and 1.2 times the initial length by adjusting the coordinates of the lower node of the outer compression rod, and the importance coefficients of each rod are calculated, which can find that: (1) The change of the length of the outer compression rod has different influences on the importance coefficients of various rods, and when the length increases from 0.8 times to 1.2 times, the importance coefficient of the outer ring cable increases from 0.48 to 0.55, which increases by 15%, and the importance coefficient of the lower chord of the tension ring decreases significantly from 0.058 to 0.035, which decreases by 40%. (2) In general, although the length of the outer compression rod has a great influence on the importance coefficients of some rods, it has little influence on the collapse resistance of the whole structure. (3) At the same time, it is found that the length of the middle compression rod has little influence on the continuous collapse resistance of the structure.

[0124] The search can make the rod importance value of the rod classification result different as the rod classification critical point, specifically: for the first group: the lower chord of the tension ring and the upper chord of the tension ring; the rod importance coefficients are 0.033 and 0.15 respectively, and the classification critical point of the ordinary rod and the important rod is determined to be in the range of [0.033, 0.15].

[0125] The importance coefficient of the chord member below the tension ring and the chord member above the tension ring is analyzed with respect to the prestress level, the cross-sectional area of the member, the radius of the outer ring cable, the radius of the inner ring cable, the length of the outer pressure rod, and the length of the middle pressure rod. It is found that the importance coefficient of the chord member below the tension ring increases with the increase of the prestress level, the decrease of the cross-sectional area of the member, the increase of the radius of the outer ring cable, the increase of the radius of the inner ring cable, the decrease of the length of the outer pressure rod, and the decrease of the length of the middle pressure rod, while the importance coefficient of the chord member above the tension ring increases with the decrease of the prestress level, the increase of the cross-sectional area of the member, the increase of the radius of the outer ring cable, the increase of the radius of the inner ring cable, the decrease of the length of the outer pressure rod, and the increase of the length of the middle pressure rod.

[0126] Through the optimization calculation of various parameters, it is determined that the classification critical point of the ordinary member and the important member is 0.08.

[0127] For the second group: the chord above the tension ring and the inner ring cable; the importance of the members is 0.15 and 0.23 respectively, and the classification critical point of the important member and the key member is determined to be in the range of [0.15, 0.23].

[0128] The importance coefficient of the chord member above the tension ring and the inner ring cable is analyzed with respect to the prestress level, the cross-sectional area of the member, the radius of the outer ring cable, the radius of the inner ring cable, the length of the outer pressure rod, and the length of the middle pressure rod. It is found that the importance coefficient of the chord member above the tension ring increases with the decrease of the prestress level, the increase of the cross-sectional area of the member, the increase of the radius of the outer ring cable, the increase of the radius of the inner ring cable, the decrease of the length of the outer pressure rod, and the increase of the length of the middle pressure rod, while the importance coefficient of the inner ring cable increases with the decrease of the prestress level, the increase of the cross-sectional area of the member, the decrease of the radius of the outer ring cable, the increase of the radius of the inner ring cable, the decrease of the length of the outer pressure rod, and the decrease of the length of the middle pressure rod.

[0129] Through the optimization calculation of various parameters, it is determined that the classification critical point of the important member and the key member is 0.19.

[0130] (4) For the cable dome structure model, the importance coefficient of the target member is calculated, and according to the principle that the more important the member is, the greater the risk of progressive collapse is, the classification critical point obtained in step (3) is used to judge the risk category of the progressive collapse.

[0131] The importance coefficients of the members of the outer ring cable and the inner ring cable are all greater than 0.19, and the dynamic response of the structure after the removal of the members is very large, which belongs to the key member. The importance coefficient of the chord member above the tension ring is between 0.19 and 0.08, and the removal of this type of member will lead to local collapse of the structure, which has a greater impact on the structure, and belongs to the important member. The importance coefficients of the other types of members are all below 0.08, and the removal of this type of member has a smaller impact on the structure and will not cause progressive collapse, which belongs to the ordinary member.

[0132] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining the progressive collapse risk of a cable dome structure, characterized by, The method comprises the following steps: (1) loading an initial cable dome structure model, calculating the bar importance coefficient of each type of bar, and judging the continuous collapse risk category of removing a bar according to the continuous collapse area and vertical node displacement after removing the bar; (2) sorting the bars after normalizing the bar importance coefficients obtained in step (1), searching for one or more groups of adjacent and continuous collapse risk category different bars; taking the ordinary bar with the largest bar importance coefficient and the important component with the smallest bar importance coefficient as the first group of adjacent and continuous collapse risk category different bars; taking the important bar with the largest bar importance coefficient and the key component with the smallest bar importance coefficient as the second group of adjacent and continuous collapse risk category different bars; (3) taking the value of the bar importance coefficient of at least one group of adjacent and continuous collapse risk category different bars obtained in step (2) as the upper and lower limits of the bar classification critical point value range; adjusting the cable dome structure model so that the bar importance coefficient of at least one bar in the group changes within the bar classification critical point value range, and judging the continuous collapse risk category of the bar according to the continuous collapse area and vertical node displacement after removing the bar, and searching for the bar importance coefficient value that can make the bar classification result different as the bar classification critical point; the adjustment of the cable dome structure model comprises adjusting the cross-sectional area of the bar, adjusting the length of the bar, adjusting the prestress level of the cable dome structure, and adjusting the radius of the ring cable of the cable dome structure; (4) calculating the bar importance coefficient of the target bar of the cable dome structure model, and judging the continuous collapse risk category of the target bar according to the principle that the more important the bar importance is, the greater the continuous collapse risk is, and using the bar classification critical point obtained in step (3).

2. The method for assessing the risk of progressive collapse of a cable-stayed dome structure as described in claim 1, characterized in that, The cable dome structure model in step (1) comprises the topological structure of each bar of the cable dome, the cross-sectional area parameters of each component, and the prestress parameters of each component.

3. The method for assessing the risk of progressive collapse of a cable-stayed dome structure as described in claim 1, characterized in that, member a member importance coefficient is calculated as follows: ， wherein, is the accumulated displacement of all nodes of the cable dome structure before removing a certain bar is the square sum of the displacement difference between the front and back displacements, is the accumulated displacement of all nodes of the cable dome structure before removing a certain bar is calculated by the following method: ， in, , , Remove a certain member respectively Before and after node along , , The displacement difference in the direction is calculated as follows: ， is the total number of structural nodes; , , , , are the displacement components of the nodes along the three directions respectively before and after the removal of a certain member of the structure. , , , , ​ 4. The method of claim 3, wherein the continuous collapse risk of the cable dome structure is determined by the following equation: ###0001### where, A: the area of the cable dome structure, W: the weight of the cable dome structure, and K: the continuous collapse risk of the cable dome structure. The bar importance coefficient is normalized, and the normalized bar importance coefficient The calculation is as follows: 。 5. The method for assessing the risk of progressive collapse of a cable-stayed dome structure as described in claim 1, characterized in that, The continuous collapse risk category is divided according to the following standards: when the continuous collapse area of the cable dome structure meets the first condition, it is determined that the cable dome has continuous collapse failure, and the bar is judged to be a key component with the highest continuous collapse risk; the first condition is that the maximum vertical node displacement of the cable dome is greater than 1 / 50 of the span and the failure area reaches 30% of the total plane area of the structure; when the continuous collapse area of the cable dome structure meets the second condition, it is determined that the cable dome has local continuous collapse failure, and the bar is judged to be an important component with a higher continuous collapse risk; the second condition is that the maximum vertical node displacement of the cable dome is greater than 1 / 50 of the span, but the failure area does not reach 30% of the total plane area of the structure, when the maximum vertical node displacement of the cable dome is less than 1 / 50 of the span, or when the maximum node displacement of the cable dome is greater than 1 / 50 of the span, but the failure area does not reach 15% of the total plane area of the structure, it is determined that the cable dome does not have continuous collapse failure, and the bar is judged to be an ordinary component with a lower continuous collapse risk.

6. The method for assessing the risk of progressive collapse of a cable-stayed dome structure as described in claim 1, characterized in that, The adjustment of the cable dome structure model in step (3) is specifically: The influence law of each design parameter of the cable dome structure model on the importance coefficient of each bar is calculated and analyzed, and each design parameter is adjusted according to the influence law of the importance coefficient of each bar in the order of increasing or decreasing degree; the design parameters of the cable dome structure model include the cross-sectional area of the bar, the length of the bar, the prestress level and the radius of the ring cable.

7. The method for assessing the risk of progressive collapse of a cable-stayed dome structure as described in claim 1, characterized in that, The search in step (3) is specifically to search for the bar importance coefficient value that can make the bar classification results different as the bar classification critical point: One of the one or more groups of adjacent and continuous collapse risk category different bars is selected as a reference bar, so that the bar importance coefficient adjusts the cable dome structure model in the order of increasing or decreasing, and the bar importance coefficient of the reference bar changes in the range of the bar classification critical point value, and the continuous collapse risk category of the reference bar is judged according to the continuous collapse area and the vertical node displacement after the bar is removed; whenever the risk category of the bar changes, the adjustment range is reduced to adjust the bar importance coefficient of the reference bar in the reverse direction, until the difference between the bar importance coefficients of the reference bars in the two adjacent continuous collapse risk category changes of the reference bar is less than a preset difference threshold, and then the bar classification critical point of the risk category change is determined between the bar importance coefficient values of the reference bars in the two adjacent continuous collapse risk category changes of the reference bar.

8. A cable dome structure continuous collapse risk judgment system characterized by comprising: a cable dome structure continuous collapse risk judgment device according to any one of claims 1 to 7. The model loading module, the bar searching module, the bar classification critical point searching module, and the continuous collapse risk judgment module are included; The model loading module is used to load an initial cable dome structure model, calculate the bar importance coefficient of each type of bar, judge the continuous collapse risk category of the bar removed according to the continuous collapse area and the vertical node displacement after the bar is removed, and submit the bar importance coefficient and the continuous collapse risk category of the bar to the bar searching module; The bar searching module is used to sort the bars according to the normalized bar importance coefficients, search one or more groups of adjacent and continuous collapse risk category different bars, and submit the one or more groups of bars and their importance coefficients to the bar classification critical point searching module; The ordinary bar with the largest bar importance coefficient and the important component with the smallest bar importance coefficient are taken as the first group of adjacent and continuous collapse risk category different bars; The important bar with the largest bar importance coefficient and the key component with the smallest bar importance coefficient are taken as the second group of adjacent and continuous collapse risk category different bars; The bar classification critical point searching module is configured to, for the at least one group of adjacent and continuous bars with different collapse risk categories, take the value of the bar importance coefficient of each bar as the upper and lower limits of the bar classification critical point value range; adjust the cable dome structure model so that the bar importance coefficient of at least one bar in the group changes within the bar classification critical point value range, and judge the collapse risk category of the bar according to the continuous collapse area and the vertical node displacement after the bar is removed, search for the bar importance coefficient value that can just make the bar classification result different as the bar classification critical point, and submit the bar classification zero critical point to the continuous collapse risk judgment module; The adjustment of the cable dome structure model comprises adjustment of the cross-sectional area of the bar, adjustment of the length of the bar, adjustment of the prestress level of the cable dome structure, and adjustment of the radius of the ring cable of the cable dome structure; The continuous collapse risk judgment module is configured to calculate the bar importance coefficient of the target bar of the cable dome structure model, and judge the collapse risk category of the bar according to the principle that the more important the bar importance is, the greater the collapse risk of the bar is, and adopt the bar classification critical point.

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