A method for evaluating the technical condition of the main load-bearing components of beam bridges

Abstract

The invention relates to the technical field of bridge assessment and maintenance, and discloses a method for evaluating the technical condition of main load-bearing components of a beam bridge, comprising the following steps: step 1: determining the weight of each component in a bridge system by using an improved hierarchical analysis method; step 2: calculating the technical condition of the component according to bridge appearance detection data; step 3: evaluating the overall technical condition PCCI of the upper component based on MAHP; and solving the problem that when using specifications to evaluate the technical condition of the main load-bearing components of a beam bridge, the relative importance of each main beam component cannot be considered, resulting in the evaluation result not being consistent with the actual situation.

Description

Technical Field

[0001] The invention relates to the technical field of bridge assessment and maintenance, and in particular to a method for assessing the technical status of a main load-bearing component of a beam bridge. Background Art

[0002] As the hub of the transportation network, bridges are important infrastructure in the transportation industry. According to incomplete statistics, the total number of highway bridges in my country has exceeded 900,000. According to the structural importance level of the bridge, the design reference period of the bridge structure is generally 100 years. During its service life, bridges need to withstand the coupling of multiple factors, such as environmental corrosion, deterioration of material properties, repeated vehicle action and vehicle overloading, which will cause diseases that affect the safety of the bridge structure and attenuation of its bearing capacity, and even catastrophic accidents such as bridge collapse. Faced with a large number of bridge clusters, in order to ensure that the bridge structure can be used normally and operate safely during its service life, the bridge management and maintenance department needs to manage and maintain the bridge throughout its life cycle. Among them, bridge inspection is an important part of bridge maintenance and can provide a basis for bridge maintenance decisions.

[0003] The assessment of the technical condition of bridges is currently a widely used means of bridge inspection. Bridge components, parts and the whole correspond to the lowest, middle and highest levels in the assessment system respectively. There is a logical progressive relationship between different levels. The main standard is the "Standard for the Assessment of the Technical Condition of Highway Bridges" (JTG / TH21-2011) (hereinafter referred to as the standard). For the main load-bearing components of a beam-type bridge composed of multiple beams, the object of the bridge component assessment is a certain beam. Through on-site inspection of the defects of the bridge components, comprehensive deductions are made for different types of defects according to the standard, and then the score of the technical condition of the bridge components is obtained. The upper load-bearing components refer to the upper structure system including all the main beam components. The standard obtains the technical condition score of the upper load-bearing components by taking the average of the scores of each component. Finally, the overall technical condition of the bridge is obtained by combining the scores of each bridge component according to the weight method. However, for the upper main load-bearing components of beam-type bridges, the traditional bridge technical condition assessment method still has certain problems:

[0004] (1) In the specification, the method for assessing the technical condition of upper load-bearing components considers the importance of each component to be the same.

[0005] (2) In fact, the contributions made by each main beam component to the normal use of the upper load-bearing components are different, and the average value method does not conform to the actual situation.

[0006] Therefore, when using the standard method to evaluate the technical condition of the main load-bearing components of a beam bridge, there is a possibility that the relative importance of each main beam component cannot be considered, resulting in the possibility that the evaluation result is inconsistent with the actual situation. In order to solve this problem, this patent proposes a method for evaluating the technical condition of the main load-bearing components of a beam bridge. Summary of the invention

[0007] The purpose of the present invention is to provide a method for evaluating the technical condition of the main load-bearing components of a beam bridge, so as to solve the problem that when using the specification to evaluate the technical condition of the main load-bearing components of a beam bridge, the relative importance of each main beam component cannot be considered, resulting in the evaluation result not being consistent with the actual situation.

[0008] The present invention provides the following technical solution: a method for evaluating the technical condition of the main load-bearing components of a beam bridge, comprising the following steps:

[0009] Step 1: Use the improved analytic hierarchy process to determine the weights of each component in the bridge system;

[0010] Step 2: Calculate the technical condition of components based on the bridge appearance inspection data;

[0011]

[0012] When x=1, U1=Dp i1 When x ≥ 2

[0013] When (j=i)

[0014]

[0015] Where: PMCI i represents the score of the i-th type of component of the upper structure, with a value range of 0 to 100 points; k represents the number of types of indicators that have deductions for the i-th type of component; x and y are introduced intermediate variables; i represents the component category; j represents the j-th type of inspection indicator for the i-th type of component; Dp ij Indicates the deduction value of the jth inspection index of the ith type of component; calculated based on the deduction values ​​of various inspection indicators of the component;

[0016] Step 3: Assess the overall technical condition PCCI of the upper structure based on MAHP;

[0017] PCCI=PMCI1×ω1+PMCI2×ω2+…+PMCI n ×ω n

[0018] Where: n represents the number of components in the bridge system, (AW) i express

[0019] The weight value of the i-th component.

[0020] Preferably, a judgment matrix is ​​constructed, and an improved hierarchical analysis method is used. The improved hierarchical analysis method judges the element a in the matrix ij It is expressed by reliability index as shown in the following formula:

[0021]

[0022] Where: m i and m j They represent the masses of plate i and plate j respectively.

[0023] Preferably, the weight of each component in the bridge system is calculated, and the weight of each component is obtained according to the constructed judgment matrix, as shown in the following formula:

[0024]

[0025] Preferably, the consistency check of the judgment matrix is ​​performed, because the element a in the judgment matrix A ij It is easy to have inconsistent judgments or contradictory results when judging the relative importance of each indicator. Therefore, it is necessary to conduct a consistency test on the judgment matrix A;

[0026] It is necessary to calculate the maximum characteristic root λ of the judgment matrix A max , calculate the consistency index CI and consistency ratio CR. If CR<0.1, the judgment matrix satisfies the consistency test.

[0027]

[0028] Where: n represents the number of components in the bridge system, (AW) i

[0029] Represents the weight value of the i-th component.

[0030] The invention has the following beneficial effects:

[0031] 1. This invention uses a weight method to calculate the overall score of the upper components. According to the different contributions of each component to the normal use of the upper load-bearing parts, the weight of each component is calculated, and the score of each component is multiplied by the weight of the component to calculate the overall score of the upper components, and the technical status of the main load-bearing components of the beam bridge is evaluated. It is no longer considered that the importance of each component is the same, and the average value of the score of each component is taken as the overall score of the upper component, which is more in line with the actual situation.

[0032] 2. Compared with the previous standard assessment methods, this invention solves the problem that when using standards to assess the technical conditions of the main load-bearing components of beam bridges, the relative importance of each main beam component cannot be taken into account, resulting in the evaluation results not being consistent with the actual situation.

[0033] 3. This invention can be applied to the technical condition assessment of the main load-bearing components of various beam-type bridges, and has simple structural calculations, convenient operation, high accuracy, and is more in line with actual conditions, thus having high promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of the present invention;

[0035] Figure 2 is a table of lateral distribution coefficients in the present invention;

[0036] Figure 3 is the element a in the judgment matrix in the present invention ij surface;

[0037] Figure 4 is the weight ω of each component in the present invention i surface;

[0038] Figure 5 The PMCI score of the 11 simply supported hollow slabs of the bridge superstructure in the present invention i surface;

[0039] Figure 6 It is the random consistency index RI table in the present invention. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention will be described clearly and completely below.

[0041] like Figure 1-6 As shown, a method for assessing the technical condition of the main load-bearing components of a beam-type bridge is used. A bridge is selected as an engineering example. The superstructure of the bridge is composed of 11 simply supported hollow slabs. The technical condition of the main load-bearing components of the superstructure of the engineering example bridge is assessed by using the method for assessing the technical condition of the main load-bearing components of a beam-type bridge proposed in the present invention, and the technical condition is compared with the assessment results in the specification.

[0042] First, the improved analytic hierarchy process (AHP) is used to determine the weights of each component in a more objective bridge system. Then, the scores of each component are calculated based on the component disease, etc. Then, the overall score of the upper component is calculated using the weight method based on the component scores. The specific calculation formula is shown in the following formula:

[0043] PCCI i =PMCI1×ω1+PMCI2×ω2+…+PMCI n ×ω n

[0044] Where: n represents the number of components in the bridge system.

[0045] The specific steps of the above-mentioned arch bridge hanger condition assessment method are as follows:

[0046] Step 1: Determine the weights of each component of the bridge superstructure using the analytic hierarchy process (AHP) method;

[0047] First, the hinged plate method is used to calculate the lateral distribution coefficient of the bridge superstructure of the engineering example. The lateral distribution coefficient can represent the load proportion distributed to each component under the load. The specific results are as follows: Figure 2 shown.

[0048] Then, according to the formula Calculate the element a in the judgment matrix ij , and construct the judgment matrix, m i and m j They represent the mass of plate i and plate j respectively. The specific results are as follows Figure 3 shown.

[0049] Finally, according to the formula Calculate the various components in the bridge superstructure system

[0050] The weight of the item ω i , according to the formula The judgment matrix is ​​checked for consistency, and the weight results are as follows: Figure 4 As shown in the formula, n represents the number of components in the bridge system, (AW) i represents the weight value of the i-th component, where the random consistency index RI is as follows Figure 6 shown.

[0051] Step 2: Calculate the technical condition of components based on the bridge appearance inspection data;

[0052] First, the appearance of each component of the superstructure of the engineering example bridge was inspected on site. The main defects of the components were transverse cracks, longitudinal cracks and concrete peeling and exposed reinforcement. According to the severity and size of the defects, the evaluation scale corresponding to the defects was determined according to the specifications. According to the formula and And calculate the technical condition score of the component, where PMCI i represents the score of the i-th type of component of the upper structure, with a value range of 0 to 100 points; k represents the number of types of indicators that have deductions for the i-th type of component; x and y are introduced intermediate variables; i represents the component category; j represents the j-th type of inspection indicator for the i-th type of component; Dp ij It represents the deduction value of the jth inspection index of the i-th component. The deduction value is calculated based on the deduction value of various inspection indicators of the component. The result is as follows: Figure 5 shown.

[0053] Step 3: Evaluate the overall technical condition PCCI of the superstructure based on MAHP; First, the overall technical condition score PCCI1 of the superstructure of the engineering example bridge is calculated using the method proposed in this patent.

[0054] PCCI1=PMCI1×ω1+PMCI2×ω2+…+PMCI n×ω n

[0055] =59×0.0767+60×0.0861+62×0.0886+60

[0056] ×0.0941+63×0.1019+62×0.1054+64×0.1019+61×

[0057] 0.0941+62×0.0886+61×0.0861+60

[0058] ×0.0767=61.394

[0059] Then, the overall technical condition PCCI2 of the bridge superstructure of the engineering example is calculated according to the standard method for comparative analysis.

[0060] PCCI2=PMCI-(100-PMCI min ) / t

[0061] Where: t is the correction factor that depends on the number of components. The superstructure of the engineering example bridge has 11 hollow slab beams, and according to the specification, t is taken as 7.9. Figure 5 PMCCCI, PMCI can be obtained min They are 61.273 and 59 respectively.

[0062] PCCI i =PMCI-(100-PMCI min ) / t=61.273-(100-

[0063] 59) / 7.9=56.083.

Claims

1. A method for evaluating the technical condition of the main load-bearing components of a beam bridge, characterized by: The following steps are involved: Step 1: Use the improved analytic hierarchy process to determine the weights of each component in the bridge system; Step 2: Calculate the technical condition of the components based on the bridge appearance inspection data; When x=1, U1=Dpi1When x≥2, (j=i) Where: PMCI i represents the score of the i-th type of component of the upper structure, with a value range of 0 to 100 points; k represents the number of types of indicators that have deductions for the i-th type of component; x and y are introduced intermediate variables; i represents the component category; j represents the j-th type of inspection indicator for the i-th type of component; Dp ij It represents the deduction value of the j-th inspection index of the i-th component; Calculate the deduction points based on various inspection indicators of components; Step 3: Assess the overall technical condition PCCI of the upper structure based on MAHP; PCCI=PMCI1×ω1+PMCI2×ω2+…+PMCI n ×ω n Where: n represents the number of components in the bridge system; Construct a judgment matrix and use the improved analytic hierarchy process to determine the element a in the matrix. ij It is expressed by reliability index as shown in the following formula: Where: mi and mj represent the mass of plate i and plate j respectively; Calculate the weight of each component in the bridge system and obtain the weight of each component according to the constructed judgment matrix, as shown in the following formula: Consistency test of judgment matrix. Since the elements aij in judgment matrix A are prone to inconsistent judgments or contradictory results when judging the relative importance of each indicator, it is necessary to perform consistency test on judgment matrix A. It is necessary to calculate the maximum characteristic root λ of the judgment matrix A max , calculate the consistency index CI and consistency ratio CR. If CR<0.1, the judgment matrix satisfies the consistency test. Where n represents the number of components in the bridge system, and (AW)i represents the weight value of the i-th component.

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