Method for calculating reliability of cable replacement scheme

Abstract

The invention relates to a method for calculating the reliability of a cable replacement scheme, and the method comprises the following steps: S1, determining random change parameters and sampling modes under different construction conditions in combination with actual conditions; s2, sampling the random change parameters in the step S1, taking a sampling result as input, and calculating a structural response under each sample; and S3, carrying out statistical comparison on the structure response results obtained under all the samples in the S2 and a control target to obtain a reliability calculation result. By using the method, enough sample results can be obtained, the sample results are compared with the control targets, the relationship between the samples and the control targets can be visually seen, and reliability results among different control targets under different construction precision and environmental influence can be obtained after statistics. And after a reliability result is obtained, the relationship between the construction condition and the control target can be quantified and becomes an index capable of intuitively comparing and judging, so that site construction can be guided, and the final construction effect of the cable replacement scheme can be evaluated.

Description

Technical Field

[0001] The invention relates to the technical field of cable-stayed bridge cable replacement engineering construction, and in particular to a method for calculating the reliability of a cable replacement scheme. Background Art

[0002] To verify the feasibility of the cable-replacement scheme and ensure the structure remains safe during the cable-replacement process, a simulation of the cable-replacement process is necessary. If only the cable-replacement construction and the most unfavorable combination are simulated in the finite element analysis model, the calculation results will only reflect the changes in the structural response during the cable-replacement process. To specifically calculate the actual state of the structure during construction, it is necessary to simulate the construction phases and the passage of time from the beginning of the construction phase to the present, and superimpose the structural changes during the cable-replacement construction to reflect the true state of the structure. Furthermore, the most unfavorable state of the structure varies under different cable-replacement schemes. However, cable-replacement schemes are often related to construction efficiency. Considering both efficiency and safety, different cable-replacement schemes have different advantages and disadvantages.

[0003] Ideally, the structural state remains consistent before and after cable replacement. However, actual construction results are influenced by a variety of factors, such as materials and construction techniques. However, in cable replacement construction, the most significant factor affecting the performance is the change in the final cable tension of the new cable. This final tension is also affected by various factors, such as tensioning errors, measurement errors, and changes in the structural state. These factors inevitably alter the structural state, and the goal of construction control is to keep these changes within a reasonable range.

[0004] There is no research on reliability analysis of cable replacement construction in the prior art. Summary of the Invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for calculating the reliability of a cable replacement scheme, which can perform reliability analysis on the structural response under the cable replacement scheme and evaluate the final construction effect of the cable replacement scheme.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for calculating the reliability of a cable replacement scheme includes the following steps:

[0008] S1. Determine the random variation parameters and sampling methods under different construction conditions based on actual conditions;

[0009] S2, samples the randomly changing parameters in S1, uses the sampling results as input, and calculates the structural response under each sample;

[0010] S3. Statistically compare the structural response results obtained under all samples in S2 with the control targets to obtain the reliability calculation results.

[0011] Furthermore, the operation process of step S1 is as follows: based on the actual construction conditions, the structural random parameters that affect the structural response are selected. The structural random parameters include material properties, cable forces, temperature effects and live loads, which are denoted as X i (i=1,2,…,n), and determine X according to the actual situation i Sampling method and distribution type.

[0012] Furthermore, the operation process of step S2 is as follows: random sampling is performed: [X1, X2, X3, ..., X n ] T Perform N sampling to generate N vector samples and will As input, the calculation is performed based on the finite element analysis method. Each vector sample corresponds to a structural response structure, and N structural response values R are calculated. j .

[0013] Furthermore, the operation process of step S3 is as follows: control targets are defined for different structural response parameters. Combined with the probability analysis method, when the structural response results exceed the control targets, it is defined as construction control failure. Otherwise, it is construction control success. The failure probability can be expressed as:

[0014]

[0015] Where: R(X) is the structural response value of the structure under random sampling parameter input;

[0016] R μ The structural response when the material parameters, load parameters, etc. are taken as the average value;

[0017] Ω e Sets the target tolerance for structural response control.

[0018] Furthermore, the control targets include a cable tension change of 1% to 3% and a deformation of 1 to 3 mm.

[0019] In general, the present invention has the following advantages:

[0020] This method can generate a sufficient number of sample results. Comparing these results with the control target allows for a clearer understanding of the relationship between the samples and the control target. Statistical analysis can then yield reliability results for different control targets under varying construction accuracy and environmental influences. This reliability result quantifies the relationship between construction conditions and the control target, creating an intuitive metric for comparison and evaluation. This allows for the selection of appropriate construction conditions and rational adjustment of the control target, ultimately guiding on-site construction and evaluating the effectiveness of cable replacement schemes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1(a) is the general layout diagram of Yamen Bridge.

[0022] Figure 1(b) is a cross-sectional view of a standard segment of the main beam of Yamen Bridge.

[0023] Figure 2 This is the cross-section of the standard segment of the main tower of the cable-stayed bridge.

[0024] Figure 3 This is the cross-section of the main pier of the cable-stayed bridge.

[0025] Figure 4 This is a cross-sectional view of the auxiliary pier of a cable-stayed bridge.

[0026] Figure 5 This is a cross-sectional view of the side pier of a cable-stayed bridge.

[0027] Figure 6 Schematic diagram of the bridge finite element model.

[0028] Figure 7 Schematic diagram of cable force difference results (1% control accuracy).

[0029] Figure 8 Schematic diagram of deformation response results (1% control accuracy).

[0030] Figure 9 Schematic diagram of cable force difference results (3% control accuracy).

[0031] Figure 10 Schematic diagram of deformation response results (3% control accuracy).

[0032] Figure 11 Schematic diagram of cable force difference results (diurnal temperature changes).

[0033] Figure 12 Schematic diagram of deformation response results (daytime temperature changes).

[0034] Figure 13 Schematic diagram of cable force difference results (nighttime temperature changes).

[0035] Figure 14 Schematic diagram of deformation response results (temperature changes at night).

[0036] Figure 15 Schematic diagram of cable force difference results (1% control accuracy + daytime temperature change).

[0037] Figure 16 Schematic diagram of deformation response results (1% control accuracy + daytime temperature change).

[0038] Figure 17 Schematic diagram of cable force difference results (3% control accuracy + diurnal temperature variation).

[0039] Figure 18 Schematic diagram of deformation response results (3% control accuracy + daytime temperature change).

[0040] Figure 19 Schematic diagram of cable force difference results (1% control accuracy + night temperature change).

[0041] Figure 20 Schematic diagram of deformation response results (1% control accuracy + night temperature change).

[0042] Figure 21 Schematic diagram of cable force difference results (3% control accuracy + night temperature change).

[0043] Figure 22 Schematic diagram of deformation response results (3% control accuracy + night temperature change).

[0044] Figure 23 Schematic diagram of the force response results of S25# cable (a).

[0045] Figure 24 Schematic diagram of the force response results of S25# cable (b).

[0046] Figure 25 Schematic diagram of the force response results of S1# cable (a).

[0047] Figure 26 Schematic diagram of the force response results of S1# cable (b).

[0048] Figure 27 Schematic diagram of the force response results of M1# cable (a).

[0049] Figure 28 Schematic diagram of the force response results of M1# cable (b).

[0050] Figure 29 Schematic diagram of the force response results of M25# cable (a).

[0051] Figure 30 Schematic diagram of the force response results of M25# cable (b).

[0052] Figure 31 Schematic diagram of the vertical deflection response results at the mid-span (a).

[0053] Figure 32 Schematic diagram of the vertical deflection response results at the mid-span (b).

[0054] Figure 33 Schematic diagram of the main tower top displacement response results (a).

[0055] Figure 34 Schematic diagram of the displacement response results of the main tower top (b).

[0056] Figure 35 Schematic diagram of construction reliability of cable tension parameters (without temperature influence).

[0057] Figure 36 Schematic diagram of construction reliability of cable tension parameters (influence of daytime temperature).

[0058] Figure 37 Schematic diagram of construction reliability of cable tension parameters (influence of nighttime temperature).

[0059] Figure 38 Schematic diagram of construction reliability of main beam vertical deflection parameters (without temperature influence).

[0060] Figure 39 Schematic diagram of construction reliability of main beam vertical deflection parameters (influence of daytime temperature).

[0061] Figure 40 Schematic diagram of construction reliability of main beam vertical deflection parameters (influence of nighttime temperature).

[0062] Figure 41 Schematic diagram of construction reliability of tower top displacement parameters (without temperature influence).

[0063] Figure 42 Schematic diagram of construction reliability of tower top deviation parameters (influence of daytime temperature).

[0064] Figure 43 Schematic diagram of construction reliability of tower top deviation parameters (influence of nighttime temperature).

[0065] Figure 44 Schematic diagram of the flow of the method for calculating the reliability of the cable replacement scheme according to the present invention. DETAILED DESCRIPTION

[0066] The present invention will be described in further detail below.

[0067] like Figure 44 As shown, a method for calculating the reliability of a cable replacement scheme includes the following steps:

[0068] S1. Determine the random variation parameters and sampling methods under different construction conditions based on actual conditions;

[0069] S2, samples the randomly changing parameters in S1, uses the sampling results as input, and calculates the structural response under each sample;

[0070] S3. Statistically compare the structural response results obtained under all samples in S2 with the construction targets to obtain the reliability calculation results.

[0071] For step S1, the specific operation process is as follows:

[0072] Combined with the actual construction conditions, the random structural parameters that affect the structural response, such as material properties, cable tension, temperature effect and live load, are selected and denoted as X i (i=1,2,…,n), and determine X according to the actual situation i Sampling method and distribution type.

[0073] For step S2, the specific operation process is as follows:

[0074] Perform random sampling: [X1, Z2, Z3, ..., Z n ] T Perform N sampling to generate N vector samples and will As input, the calculation is performed based on the original finite element analysis method. Each vector sample corresponds to a structural response structure, and N structural response values E can be calculated. j .

[0075] For the S3 step, the specific operation process is as follows:

[0076] Combined with the probability analysis method, when the structural response cannot meet the control target requirements, it can be considered that the construction control has failed, and the failure probability can be expressed as:

[0077]

[0078] Where: R(X) is the structural response value of the structure under random sampling parameter input;

[0079] R μ —Structural response when material parameters, load parameters, etc. are taken as average values;

[0080] Ω e ——Permissible range of structural response control target.

[0081] The proposed method for calculating the reliability of cable replacement schemes reveals that structures will respond differently under the influence of different random structural parameter combinations. Reliability analysis of the structural responses under these cable replacement schemes can be used to evaluate the ultimate construction effectiveness of these schemes. Reliability calculations and evaluations based on different construction conditions and control objectives can help better select appropriate construction accuracy as a construction termination condition and more reasonable control objectives.

[0082] As shown in Figure 1(a), Figure 1(b), Figure 2-Figure 5As shown, the cable-stayed bridge cable replacement project of Yamen Bridge is taken as an example. The total width of the cable-stayed bridge is 26.8m, the total length is 1289.22m, the main bridge length is 668m, and the span combination is 50m+115m+338m+115m+50m. Each side span is equipped with an auxiliary pier. The main pier tower and beam are consolidated, and the main beam is a single-box five-chamber section. The main pier adopts a double-walled flexible pier; the auxiliary pier adopts a flexible thin-walled hollow pier; the side pier is a cantilever cap beam with a double-column pier body. The main tower adopts a single-column bridge tower, and the tower top is 73.5m away from the bridge deck. There are 200 cable-stayed cables in the entire bridge. The finite element analysis model is as follows Figure 6 shown.

[0083] Here, only the cable replacement scheme for replacing a single stay cable in a single construction step is demonstrated.

[0084] According to the finite element analysis model, m structural responses under unit change of the cable force of n cables can be obtained, thereby obtaining an m×n influence matrix M1.

[0085] Considering the site environment and construction conditions, cable force variations and temperature variations were selected as structural random parameters, and the distribution types were determined as shown in Table 1. The initial state is the nighttime temperature; the diurnal temperature difference indicates that the initial measurement is at night, but cable adjustment construction is carried out during the day, when the temperature is likely to rise. A truncated normal distribution is used for simulation; the nighttime temperature difference indicates that the initial measurement is at night, and cable adjustment construction is also carried out at night, simulating temperature variations at different times of the day and at different times of the night.

[0086] Table 1 Structural random parameter distribution types

[0087]

[0088] Note: T i is the initial state force of the i-th cable;

[0089] p is the control accuracy of cable tension adjustment construction (e.g., the cable tension can be adjusted to within the range of target cable tension ±p during construction).

[0090] During cable replacement, temperature changes can cause changes in the internal forces of the entire bridge. However, as long as the external conditions remain consistent, the internal forces of the bridge structure will remain consistent. Therefore, temperature changes only affect measurements during construction, causing construction errors. Therefore, when calculating the impact of temperature changes, temperature changes are converted into temperature-dependent cable force changes as input. Using a finite element analysis model, the temperature-dependent cable force changes of n cables can be determined, resulting in a 1×n influence matrix M2.

[0091] According to the random parameter distribution type of the structure shown in Table 1, sampling is performed N times. The temperature change sampling results are converted into cable force changes and superimposed on the cable force changes to obtain three n×N sampling results M3, M4, and M5 (no temperature difference, daytime temperature difference, and nighttime temperature difference, respectively).

[0092] By multiplying the influence matrix M1 with the three sampling results respectively, three m×N sample results can be obtained. Each line of the sample results is the N response results of a certain structural response.

[0093] Control targets can be defined for different structural response parameters. When the structural response exceeds the control target, it is defined as failure, and vice versa. Here, the reliability analysis is conducted with control targets for cable force changes within 1% to 3% and deformations within 1 to 3 mm.

[0094] Table 2 Probability of cable failure (%) (no temperature effect)

[0095]

[0096] Table 3 Deformation failure probability (%) (no temperature effect)

[0097]

[0098]

[0099] Table 4 Probability of cable failure (%) (influenced by random temperature at night)

[0100]

[0101] Table 5 Probability of cable failure (%) (influenced by random temperature at night)

[0102]

[0103]

[0104] Table 6 Deformation failure probability (%) (influenced by random temperature at night)

[0105]

[0106] Table 7 Deformation failure probability (%) (influenced by random temperature at night)

[0107]

[0108]

[0109] Table 8 Probability of cable failure (%) (influenced by random temperature during the day)

[0110]

[0111] Table 9 Probability of cable failure (%) (influenced by random temperature during the day)

[0112]

[0113] Table 10 Deformation failure probability (%) (influenced by random temperature during the day)

[0114]

[0115]

[0116] Table 11 Deformation failure probability (%) (influenced by random temperature during the day)

[0117]

[0118] (1) Pass Figures 7 to 22 The cable force and deformation results under the conditions of no temperature, daytime temperature difference, and nighttime temperature difference can intuitively show the relationship between the sample results and the control objectives;

[0119] (2) Pass Figures 23 to 34 The sample results of partial structural responses can intuitively compare the differences under different construction accuracy and temperature difference conditions.

[0120] (3) According to Tables 2 to 11 and Figures 35 to 43 The reliability results of some parameters can be used to compare the relationships between different construction progress, construction temperature differences and control objectives.

[0121] (4) Based on the above charts, the following conclusions can be drawn: ① Temperature has a significant impact on construction results. ② When there is no temperature difference, under the selected control target, the deformation parameter reliability is higher than 90% only when the cable adjustment accuracy is higher than 1%. The reliability in other cases is as low as 27.6%. When there is a daytime temperature difference, the reliability of the mid-span vertical deflection is the highest, only 39.2%. It can be seen that when there is a temperature influence, the success rate of controlling the final deformation within the target is low.

[0122] In summary, this method can obtain enough sample results. By comparing them with the control targets, the relationship between the samples and the control targets can be intuitively seen. After statistics, the reliability results between different control targets under different construction accuracies and environmental influences can be obtained.

[0123] Once the reliability results are obtained, the relationship between construction conditions and control objectives can be quantified, becoming an indicator that can be intuitively compared and evaluated. This allows for the selection of appropriate construction conditions and the rational adjustment of control objectives, ultimately guiding on-site construction.

[0124] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for calculating the reliability of a cable replacement scheme, characterized by: The following steps are included: S1. Determine the random variation parameters and sampling methods under different construction conditions based on actual conditions; S2, samples the randomly changing parameters in S1, uses the sampling results as input, and calculates the structural response under each sample; S3. Statistically compare the structural response results obtained under all samples in S2 with the control targets to obtain the reliability calculation results.

2. The method for calculating the reliability of a cable replacement scheme according to claim 1, characterized in that: The operation process of step S1 is as follows: Based on the actual construction conditions, the structural random parameters that affect the structural response are selected. The structural random parameters include material properties, cable forces, temperature effects and live loads, which are denoted as X i (i=1,2,…,n), and determine X according to the actual situation i Sampling method and distribution type.

3. The method for calculating the reliability of a cable replacement scheme according to claim 2, characterized in that: The operation process of step S2 is as follows: random sampling: [X1, X2, X3, ..., X n ] T Perform N sampling to generate N vector samples and will As input, the calculation is performed based on the finite element analysis method. Each vector sample corresponds to a structural response structure, and N structural response values R are calculated. j .

4. The method for calculating the reliability of a cable replacement scheme according to claim 3, characterized in that: The operation process of step S3 is as follows: control targets are defined for different structural response parameters. Combined with the probability analysis method, when the structural response results exceed the control targets, it is defined as construction control failure. Otherwise, it is construction control success. The failure probability can be expressed as: Where: R(X) is the structural response value of the structure under random sampling parameter input; R μ The structural response when the material parameters, load parameters, etc. are taken as the average value; Ω e Sets the target tolerance for structural response control.

5. The method for calculating the reliability of a cable replacement scheme according to claim 1, characterized in that: The control targets include cable tension change of 1% to 3% and deformation of 1 to 3 mm.

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