Bridge crossing feasibility evaluation method for large-piece transportation

Abstract

The invention mainly relates to the technical field of bridge engineering, in order to quickly judge the feasibility of large-piece transportation bridge crossing in the feasibility stage, the invention provides a large-piece transportation bridge crossing feasibility evaluation method, and the feasibility of large-piece transportation bridge crossing can be evaluated only by obtaining the number of bridge lanes of a to-be-adopted line for large-piece transportation and the road grade of a whole road. A total load effect method is adopted to calculate the ratio of the large piece transportation special load effect envelope value under all spans in the bridge span library corresponding to the bridges in the different bridge groups to the load effect envelope value of the design load, and meanwhile, according to the road grade and the number of lanes of the to-be-adopted line, the bridge is planned to be designed; carrying out load arrangement according to the most disadvantageous arrangement of the space, calculating the ratio of the special load effect envelope value of the trial design bridge large piece transportation corresponding to all spans in the bridge span library to the design load effect envelope value, and judging whether the large piece transportation can pass or not according to the calculated maximum ratio; and all bridges on the route to be adopted do not need to be detected and evaluated one by one.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of bridge engineering, and in particular to a method for evaluating the feasibility of transporting large components across bridges. Background Art

[0002] Large-scale projects involve various large-scale mechanical equipment. Such equipment generally needs to be manufactured in a factory and then transported to the project area for installation. The transportation plan of the equipment needs to be basically analyzed in the feasibility study report of the project, and a conceptual judgment on the feasibility needs to be made. If the transportation route is long, there are many alternative routes. The road design parameters of each route are different, the number of bridges is huge, and the boundary conditions such as the structural type of each bridge are different. At the same time, because the bridge design documents on each route cannot be completely collected in the early stage of engineering design work. The general approach is to only evaluate the linear indexes such as the width and turning radius of the road, and the load influence is not considered; the other is to detect and evaluate the existing bridges, and then check the bearing capacity of each bridge one by one. The problems existing in the above two methods are as follows: If the load influence is directly not considered, the final evaluation result may not conform to the actual situation and be invalid. The method of directly evaluating in the implementation stage often involves multiple route comparisons, resulting in a long time cycle and a large workload. Summary of the Invention

[0003] Technical Problem to be Solved by the Invention

[0004] Provide a method for evaluating the feasibility of transporting large components across bridges, and quickly judge the feasibility of transporting large components across bridges in the feasibility study stage.

[0005] Technical Solution Adopted by the Invention to Solve the Above Technical Problem

[0006] A method for evaluating the feasibility of transporting large components across bridges includes:

[0007] Establish a bridge span database, which includes all span values of conventional bridges;

[0008] Collect the road grade and the number of bridge lanes of the route proposed for large-component transportation, determine the road design load according to the road grade in accordance with the current specifications, and divide the bridges into different bridge groups according to the number of lanes of the bridges;

[0009] Based on the total load effect method, under the conditions that the design load travels in the middle of each lane and the special load for large-component transportation travels in the middle of the bridge width, calculate the ratio of the envelope value of the special load effect for large-component transportation and the envelope value of the load effect of the design load for all spans of the bridges corresponding to different bridge groups in the bridge span database respectively, and record the maximum value as M;

[0010] For all bridge spans in the bridge span library, select all applicable bridge types corresponding to the respective spans for trial design. Respectively, perform bridge cross-section layout according to the road class and number of lanes of the proposed route by taking values in accordance with the current specifications. Calculate the ratio of the envelope value of the special load effect for large-piece transportation and the envelope value of the design load effect for the trial-designed bridge by arranging loads according to the most unfavorable spatial layout, and record the maximum value as N;

[0011] Select the maximum value between N and M and record it as Kmax. If Kmax <= A, large-piece transportation can pass through the corresponding bridge. If A < Kmax <= B, large-piece transportation can pass through the corresponding bridge, but the bridge needs to be strengthened. If Kmax > B, then a special study needs to be conducted on the corresponding bridge to determine whether it can pass, where A and B are set values and A is less than B.

[0012] Furthermore, the calculation of the ratio of the envelope value of the load effect of the large-piece transportation load and the envelope value of the design load effect for all spans in the bridge span library corresponding to the bridges in different bridge groups respectively includes:

[0013] Respectively calculate the envelope value of the load effect S ud1 under the ultimate limit state of bearing capacity corresponding to the design load of bridges with different calculated spans in different bridge groups according to the total load effect method, and the envelope value of the load effect S d1 under the serviceability limit state, as well as the envelope value of the load effect S ud2 under the ultimate limit state of bearing capacity corresponding to the special load for large-piece transportation and the envelope value of the load effect S d2 under the serviceability limit state;

[0014] Calculate Record the maximum value as K1, calculate Record the maximum value as K2, and the maximum value between K1 and K2 is M.

[0015] Furthermore, the specific calculation of the ratio of the envelope value of the special load effect for large-piece transportation and the envelope value of the design load effect for the trial-designed bridge by arranging loads according to the most unfavorable spatial layout includes:

[0016] For the trial-designed bridge, arrange loads according to the most unfavorable spatial layout respectively, and calculate the envelope value of the load effect S ud1i under the ultimate limit state of bearing capacity corresponding to the design load and the envelope value of the load effect S d1i under the serviceability limit state, as well as the envelope value of the load effect S ud2i under the ultimate limit state of bearing capacity corresponding to the special load for large-piece transportation and the envelope value of the load effect S d2i under the serviceability limit state;

[0017] Calculate Denote the maximum value as K3 and calculate Denote the maximum value as K4, and the maximum value between K3 and K4 is N.

[0018] Furthermore, the method for determining the type of special load for large-piece transportation is as follows: evaluate the maximum vehicle width and maximum vehicle length allowed for the proposed route based on the total weight of large-piece transportation and the design parameters of the proposed route, and use the uniform load formed by evenly distributing the total weight of the large-piece transport vehicle and cargo within the rectangle enclosed by the maximum vehicle width and maximum vehicle length as the type of special load for large-piece transportation.

[0019] Furthermore, the method further includes: fitting the construction age, bridge type, and operation and maintenance status of the bridge on the proposed route into a boundary condition coefficient w. When the construction age, bridge type, and operation and maintenance status are beneficial to the bridge bearing capacity, the boundary condition coefficient w is less than 1; otherwise, the boundary condition coefficient w is equal to 1. If w*Kmax <= A, large-piece transportation can pass; if A < w*Kmax <= B, large-piece transportation can pass, but the bridge needs to be strengthened; if w*Kmax > B, a special study on the bridge is required.

[0020] Furthermore, the specific process of fitting the construction age, bridge type, and operation and maintenance status of the bridge on the proposed route into a boundary condition coefficient w includes:

[0021] Denote the construction age of the bridge on the proposed route as w1, the bridge type as w2, and the bridge operation and maintenance status as w3, and w = w1*w2*w3.

[0022] Furthermore, when the construction age of the bridge is greater than or equal to 5 years from now, w1 is 1; when the construction age is within 1 year from now, w is 0.95, and for other years, linear interpolation is used;

[0023] When the bridge type is a hollow slab bridge, the value of w2 is 1; when the bridge type is a prestressed concrete small box girder, T beam, or integral box girder, the value of w2 is 0.95;

[0024] When the operation and maintenance status of the bridge is inspected according to the inspection frequency specified in the code and there are corresponding inspection records, the value of w3 is 0.95; otherwise, the value is 1.

[0025] Furthermore, A is 0.95 and B is 1.2.

[0026] Furthermore, the specific rules for the transverse layout of the bridge specifically include: the distance between two precast units of the prefabricated structure takes the maximum value within the applicable range; the transverse layout of the cantilever slab of the box girder and solid slab structure takes the maximum value within the applicable range, and the web spacing of the box girder takes the maximum value within the applicable range.

[0027] Advantages of the present invention

[0028] (1) A feasibility evaluation method for large-piece transportation across bridges provided by the present invention. When the basic information such as the bridge health condition, reinforcement configuration, and structural dimensions is unknown and the true bearing capacity of the bridge cannot be determined, only the number of bridge lanes on the route proposed for large-piece transportation and the road grade of the entire highway need to be obtained. The ratio of the special load effect envelope value of large-piece transportation to the load effect envelope value of the design load for all spans in the bridge span library corresponding to the bridges in different bridge groups is calculated respectively using the total load effect method. At the same time, the bridge is designed according to the road grade and lane number of the proposed route, and the load is arranged according to the most unfavorable spatial layout to calculate the ratio of the special load effect envelope value of large-piece transportation to the design load effect envelope value for all spans corresponding to the bridges in the bridge span library. Whether large-piece transportation can pass is judged according to the range where the maximum value among all the calculated ratios of the special load effect of large-piece transportation to the design load effect is located. It is not necessary to detect and evaluate each bridge on the proposed route one by one, which can effectively improve the efficiency of judging whether large-piece transportation can cross the bridge in the project feasibility study stage.

[0029] (2) Integrate information such as road maintenance conditions, construction age, and structural type into a boundary condition coefficient, and adjust the maximum value of the ratio of the special load effect of large-piece transportation to the design load effect based on the boundary condition coefficient. When the bridge information such as the construction age, structural type, and maintenance conditions of the bridge is clearer and is beneficial to the bridge bearing capacity, the boundary coefficient condition is smaller, and the feasibility evaluation result of large-piece transportation across the bridge is more accurate.

[0030] (3) In the case where the special load loading pattern of large-piece transportation is not clear, considering the flexibility of the axle arrangement of the special vehicle for large-piece transportation and the usage condition that the special load of large-piece transportation generally travels in the middle, the load pattern of the special load of large-piece transportation is optimized, which provides the possibility for structural calculation of the unclear special load of large-piece transportation; in the case where the transverse layout of the bridge structure is not clear and the transverse distribution coefficient cannot be used for structural calculation, the total load effect method is used to calculate the structural effect, providing a new calculation method.

[0031] (4) Extract the most easily obtained basic information for the route to be evaluated, and establish a conventional bridge database in combination with experience. Use the evaluation of the special load passability of the bridges in the conventional bridge database to replace the evaluation of the bridges on the route to be evaluated. Detailed implementation mode

[0032] According to the locations of the large-scale mechanical equipment plant site and work area, initially screen out the routes available for transporting large-scale mechanical equipment; collect the relevant design parameters of the proposed route, including road grade, construction age, design documents, and descriptions of operation and maintenance and reinforcement treatment, etc.

[0033] Conduct a simple survey of the proposed transportation route (which can use a driving recorder, etc.), identify special bridge structures, such as cable-stayed bridges, suspension bridges, bridges with a single-span span exceeding 50 meters, and bridge load limits, etc. Collect road parameters, including road grade, number of lanes, lane width, construction year, bridge diseases, etc.

[0034] The design load is determined according to the road grade of the proposed transportation route in accordance with the current specifications.

[0035] Based on the total weight of the heavy haul transportation equipment and the inspection results, evaluate the maximum vehicle width and maximum vehicle length allowed for the transportation route. The uniform load formed by evenly distributing the total weight of the heavy haul vehicle and cargo within the rectangle enclosed by the maximum vehicle width and maximum vehicle length is used as the type of special load for heavy haul transportation.

[0036] Basic assumptions that the proposed evaluation route should meet: 1. Highway bridges are designed and constructed normally and managed according to modern operation and maintenance concepts; 2. The number of lanes is less than or equal to 4; 3. The bridge spans in each route meet the requirements of the bridge span library; 4. The special load vehicle for heavy haul transportation drives in the middle of the lane.

[0037] Determine the calculation span library of typical conventional bridges, establish a bridge span library, and the bridge span library includes at least bridge spans of 5.0, 6.0, 8.0, 10, 13, 16, 20, 25, 30, 35, 40, 45, 50m.

[0038] According to the basic assumption conditions, divide multiple bridge groups according to the number of bridge lanes. Each lane group contains all the spans in the bridge span library. Based on the total load effect method, under the conditions of the design load driving in the middle of its respective lane and the special load for heavy haul transportation driving in the middle of the bridge width, calculate the load effects under the ultimate limit state of bearing capacity and the serviceability limit state. Calculate the load effects under the ultimate limit state of bearing capacity and the serviceability limit state of the bridge according to the design load in accordance with the current specifications, and their values are S ud1 and S d1 . S ud1 =γ 01 γ Q1 Q 1k ,Q 1k =(1 + μ)*ξ*m*(q k *ω + P k *y) where γ 01 is the structural importance coefficient, which is taken according to the road grade of the proposed evaluation road in accordance with the current specifications; γ Q1 is the partial coefficient of vehicle load, which is taken according to the current specifications; Q 1kis the standard value of the vehicle load effect, calculated using the total load effect method; 1+μ is the impact factor of the vehicle load, taking 1.05; ξ is the lateral lane loading coefficient, obtained according to the road class and number of lanes of the road to be evaluated in accordance with the current code; m is the number of lanes, the same as the survey result; q k is the magnitude of the uniformly distributed load in the lane load, obtained according to the road class of the road to be evaluated in accordance with the current code; ω is the area of the internal force influence line at the application point of the uniformly distributed load; P k is the magnitude of the concentrated load in the lane load, obtained according to the road class of the road to be evaluated in accordance with the current code; y is the vertical coordinate value of the internal force influence line at the application point of the concentrated load. The effect S of the design value of the vehicle load under the normal use state d1 =Q 1k .

[0039] Calculate the load effects S of the bearing capacity limit state of the same-span bridge under special loads respectively ud2 =ηγ 02 γ Q2 Q 2k , Q 2k =q 2k *ω2, γ 02 structural importance coefficient, taking 1.0; γ Q2 partial coefficient of special load, taking 1.1; Q 2k standard value of special load, η load effect amplification coefficient of special load, calculated according to the road class by combining the specified lane width in the code with the surveyed driving lane width, η=(ratio of the total driving lane width to the maximum width of the special load vehicle allowed multiplied by the lateral loading coefficient - 0.5)> = 1; q 2k magnitude of the uniformly distributed load of special load; ω2 area of the internal force influence line at the application point of the uniformly distributed load. The load effect S under the normal use limit state d2 =Q 2k .

[0040] Calculate the envelope value of the load effect S corresponding to the design load of bridges with different spans in the bridge group under the bearing capacity limit state and the envelope value of the load effect S corresponding to the special load of large-scale transportation under the bearing capacity limit state respectively according to the above methods, and calculate the ratio of the special load of large-scale transportation and the design load at the same position and the same load effect under the bearing capacity limit state ud1 Take the maximum value as K1, and the envelope value of the load effect S corresponding to the design load of bridges with different spans in the corresponding bridge group under the normal use limit state and the load effect S corresponding to the special load of large-scale transportation under the normal use limit state respectively ud2 Take the maximum value as K1, and the envelope value of the load effect S corresponding to the design load of bridges with different spans in the corresponding bridge group under the normal use limit state and the load effect S corresponding to the special load of large-scale transportation under the normal use limit state respectively Take the maximum value among them as K1, and the envelope value of the load effect S corresponding to the design load of bridges with different spans in the corresponding bridge group under the normal use limit state and the load effect S corresponding to the special load of large-scale transportation under the normal use limit state respectively d1 Take the maximum value among them as K1, and the envelope value of the load effect S corresponding to the design load of bridges with different spans in the corresponding bridge group under the normal use limit state and the load effect S corresponding to the special load of large-scale transportation under the normal use limit state respectively d2The envelope value, and calculate the ratio of the special load for large-piece transportation and the design load at the same location and the same load effect under the serviceability limit state. Take the maximum value among them as K2.

[0041] According to the number of lanes and the road class of the proposed route, trial design the bridges on the proposed route respectively.

[0042] Span determination: Assume that any proposed route contains bridges with spans of 5.0, 6.0, 8.0, 10, 13, 16, 20, 25, 30, 35, 40, 45, 50m.

[0043] Bridge type determination: In the bridge type library, for bridges with spans of 5 - 20m, the hollow slab and solid slab bridge structures are adopted; for 20 - 40m, prestressed concrete small box girders and T-girders are adopted; for 40 - 50m, prestressed concrete T-girders and steel box girders are adopted, and for continuous beams, prestressed concrete continuous box girders are used for bridge layout; when multiple bridge types are applicable for the same span, trial design of the bridges shall be carried out separately.

[0044] Bridge transverse layout rules: The number of lanes is the same as the surveyed number of the proposed route. For the trial design of the bridge width, the cross-section layout of the bridge is determined according to the road class and the number of lanes of the proposed route by referring to the current code. For the precast structure, the distance between two precast units takes the maximum value within the applicable range; for the cantilever slab of the box girder and solid slab structure, it takes the maximum value within the applicable range; for the web spacing of the box girder, it takes the maximum value within the applicable range.

[0045] Select the bridge type according to the bridge span. The bridge type selection is carried out by the exhaustive method. Select all the applicable bridge types under the corresponding span, and carry out the trial design of the bridge according to the corresponding bridge transverse layout rules. Calculate the load effect S under the ultimate limit state corresponding to the design load of the bridge with different calculated spans according to the spatial most unfavorable layout. ud1i The envelope value of S and the load effect S under the serviceability limit state. d1i The envelope value, and the load effect S under the ultimate limit state corresponding to the special load for large-piece transportation. ud2i The envelope value of S and the load effect S under the serviceability limit state. d2i The envelope value, where i represents a certain beam or web; the calculation of the load effect envelope value can be carried out by using finite element software according to the current code, and the parameters are taken as follows:

[0046] Design load: The numerical value of the design load is taken according to the road class of the proposed road to be evaluated by referring to the current code; the number of traffic lanes is the same as the survey conclusion of the proposed route, and the traffic lane layout is carried out evenly within the bridge width range; γ 01 is the structural importance coefficient, which is taken according to the road class of the proposed road to be evaluated by referring to the current code; γ Q1is the partial coefficient of vehicle load, which is taken according to the current code; Q 1k is the standard value of vehicle load effect, which is calculated by arranging the design load according to the most unfavorable layout in space; 1+μ is the impact coefficient of vehicle load, which is taken according to the calculation structure according to the code; ξ is the transverse lane loading coefficient, which is taken according to the road grade and the number of lanes of the road to be evaluated according to the current code.

[0047] Special load for heavy haul transportation: According to the total weight of the heavy haul transportation equipment provided by the relevant engineering specialties and the inspection results, the maximum vehicle width and maximum vehicle length allowed for the transportation route are evaluated. The uniform load formed by evenly distributing the total weight of the vehicle and cargo of the heavy haul transport vehicle within the rectangle enclosed by the maximum vehicle width and maximum vehicle length is used as the form of the special load for heavy haul transportation; it is considered to travel in the center of the bridge cross-section; γ 02 Structural importance coefficient, taking 1.0; γ Q2 Partial coefficient of special load, taking 1.1; Q 2k Standard value of special load, the load is arranged according to the most unfavorable layout in the longitudinal bridge direction, and the load effect amplification coefficient η of special load is not considered.

[0048] Calculate the ratios of the special load for heavy haul transportation corresponding to all positions to the load effects under the ultimate limit state of bearing capacity corresponding to the design load respectively Record the maximum value as K3, and calculate the ratios of the special load for heavy haul transportation corresponding to all positions to the load effects under the serviceability limit state corresponding to the design load respectively Record the maximum value as K4.

[0049] In this embodiment, the proposed route includes several bridges (and it is found through investigation that there are no special structures such as suspension bridges and cable-stayed bridges), the highway grade is Class I highway, and there are two lanes.

[0050] According to the two known conditions of double lanes and the highway grade being Class I, it can be known that the bridge design load is Highway-I. Draw the bridge drawings with spans of 5.0, 6.0, 8.0, 10, 13, 16, 20, 25, 30, 35, 40, 45, and 50 m respectively (including the transverse layout. For bridges with spans of 5 - 20 m, the hollow slab and solid slab bridge structures are adopted; for 20 - 40 m, prestressed concrete small box girders and T-girders are adopted; for 40 - 50 m, prestressed concrete T-girders and steel box girders are adopted; for continuous beams, prestressed concrete continuous box girders are used for bridge layout); now taking the 30-m span as an example, prestressed concrete small box girders and T-girders can be adopted, and the bridge trial design is carried out according to prestressed concrete small box girders and T-girders respectively; now taking the small box girder as an example, for a 30-m double-lane prestressed concrete small box girder, 4 small box girders need to be arranged transversely, and the spacing between the small box girders is 2.5 m. According to this transverse layout, the structural calculations are carried out according to Highway-I and special loads respectively. Taking the mid-span moment as an example, the moment of the side beam corresponding to Highway-I under the ultimate bearing capacity state is 100 kn.m, and the moment of the side beam corresponding to the special load under the ultimate bearing capacity state is 80 kn.m, then the ratio K3 is 0.8.

[0051] Take the maximum value among K1, K2, K3, and K4 as Kmax. If Kmax <= A, heavy haul transportation can pass; if A < Kmax <= B, heavy haul transportation can pass, but the bridge needs to be strengthened; if Kmax > B, a special study on the bridge is required.

[0052] Preferably, the bridge construction age, bridge type, and operation and maintenance status of the proposed route are synthesized into the boundary condition coefficient w. When the bridge construction age, bridge type, and operation and maintenance status are favorable to the bridge bearing capacity, the boundary condition coefficient w is less than 1; otherwise, the boundary condition coefficient w is equal to 1. If w * Kmax <= A, heavy haul transportation can pass; if A < w * Kmax <= B, heavy haul transportation can pass, but the bridge needs to be strengthened; if w * Kmax > B, a special study on the bridge is required, where A is 0.95 and B is 1.2.

[0053] The calculation method of the boundary condition coefficient w is as follows: obtain the boundary condition coefficient w1 of the bridge construction age, the boundary condition coefficient w2 of the bridge type, and the boundary condition coefficient w3 of the operation and maintenance status respectively, and finally multiply w1, w2, and w3 to obtain the final value of the boundary condition coefficient w; specifically, in this embodiment, when the bridge construction age is greater than or equal to 5 years from now, the corresponding boundary condition coefficient w1 is 1, when the bridge construction age is 1 year from now, w1 is 0.95, and for other years, linear interpolation is used; the boundary condition coefficient w2 of the bridge type is specifically: the boundary condition coefficient w2 of the hollow slab bridge takes the value of 1, and the boundary adjustment coefficient w2 of the prestressed concrete small box girder, T beam, and integral box girder is 0.95; operation and maintenance status: when the inspection is carried out according to the inspection frequency specified in the specification and there are corresponding inspection records, w3 takes the value of 0.95, and in other cases, it takes 1.

Claims

1. A feasibility assessment method for transporting large items across a bridge, characterized in that: Including: Establishing a bridge span library, which includes all span values in conventional bridges; Collecting the road grade and the number of bridge lanes of the route proposed for heavy haul transportation, determining the road design load according to the road grade in accordance with the current specifications, and classifying bridges into different bridge groups according to the number of lanes of the bridges; Based on the total load effect method, under the conditions that the design load travels in the middle of each lane and the special load for heavy haul transportation travels in the middle of the bridge width, calculating the ratios of the envelope values of the special load effects for heavy haul transportation and the envelope values of the load effects of the design load for all spans in the bridge span library corresponding to the bridges in different bridge groups respectively, and recording the maximum value as M; For all spans in the bridge span library, selecting all suitable bridge types corresponding to the respective spans for trial design, respectively arranging the bridge cross-section according to the road grade and the number of lanes of the proposed route by taking values in accordance with the current specifications, and calculating the ratios of the envelope value of the special load effect for heavy haul transportation and the envelope value of the load effect of the design load for the trial-designed bridge according to the most unfavorable spatial layout, and recording the maximum value as N; Selecting the maximum value between N and M and recording it as Kmax. If Kmax <= A, heavy haul transportation can pass through the corresponding bridge. If A < Kmax <= B, heavy haul transportation can pass through the corresponding bridge, but the bridge needs to be strengthened. If Kmax > B, a special study needs to be conducted on the corresponding bridge to determine whether it can be passed, where A and B are set values, and A is less than B.

2. The feasibility assessment method for transporting large items across a bridge according to claim 1 is characterized in that: The step of respectively calculating the ratios of the envelope values of the load effects of the special heavy haul transportation loads and the envelope values of the load effects of the design loads for all spans in the bridge span library corresponding to the bridges in different bridge groups includes: According to the total load effect method, the load effect S corresponding to the design load of bridges with different calculation spans in different bridge groups under the ultimate bearing capacity state is calculated respectively. ud1 The envelope value and load effect S under the normal serviceability limit state d1 The envelope value of and the load effect S under the ultimate load capacity state corresponding to the special load of large-scale transportation ud2 The envelope value and load effect S under the normal serviceability limit state d2 The envelope value of calculate Let the maximum value be K1, and calculate The maximum value is recorded as K2, and the maximum value between K1 and K2 is M.

3. The feasibility assessment method for transporting large items across a bridge according to claim 1 is characterized in that: The step of specifically calculating the ratios of the envelope value of the special load effect for heavy haul transportation and the envelope value of the load effect of the design load for the trial-designed bridge according to the most unfavorable spatial layout for load arrangement includes: The loads of the trial designed bridges are arranged according to the most unfavorable spatial arrangement, and the load effect S corresponding to the design load under the ultimate bearing capacity state is calculated. ud1i The envelope value and load effect S under the normal serviceability limit state d1i The envelope value of and the load effect S under the ultimate load capacity state corresponding to the special load of large-scale transportation ud2i The envelope value and load effect S under the normal serviceability limit state d2i The envelope value of calculate Let the maximum value be K3, and calculate The maximum value is recorded as K4, and the maximum value of K3 and K4 is recorded as N.

4. The feasibility assessment method for transporting large items across a bridge according to claim 1 is characterized in that: The method for determining the type of the special heavy haul transportation load is: evaluating the maximum vehicle width and the maximum vehicle length allowed for the proposed route based on the total weight of the heavy haul transportation and the design parameters of the proposed route, and taking the uniform load formed by evenly distributing the total weight of the vehicle and cargo of the heavy haul transport vehicle within the rectangle enclosed by the maximum vehicle width and the maximum vehicle length as the type of the special heavy haul transportation load.

5. The feasibility assessment method for transporting large items across a bridge according to claim 1 is characterized in that: The method further includes: fitting the bridge construction year, bridge type, and operation and maintenance status of the proposed route into a boundary condition coefficient w. When the bridge construction year, bridge type, and operation and maintenance status are favorable to the bridge bearing capacity, the boundary condition coefficient w is less than 1, otherwise the boundary condition coefficient w is equal to 1; if w * Kmax <= A, heavy haul transportation can pass through. If A < w * Kmax <= B, heavy haul transportation can pass through, but the bridge needs to be strengthened. If w * Kmax > B, a special study is conducted on the bridge.

6. The feasibility assessment method for transporting large items across a bridge according to claim 5 is characterized in that: The step of specifically fitting the bridge construction year, bridge type, and operation and maintenance status of the proposed route into a boundary condition coefficient w includes: Recording the bridge construction year of the proposed route as w1, the bridge type as w2, and the bridge operation and maintenance status as w3, and w = w1 * w2 * w3.

7. The feasibility assessment method for transporting large items across a bridge according to claim 6 is characterized in that: When the bridge construction year is greater than or equal to 5 years from now, w1 is 1. When the bridge construction year is within 1 year from now, w is 0.

95. For other years, it is interpolated linearly. When the bridge type is a hollow slab bridge, the value of w2 is 1; when the bridge type is a stressed concrete small box girder, T-beam, or integral box girder, the value of w2 is 0.95; When the operation and maintenance status of the bridge is inspected according to the inspection frequency specified in the specification and has corresponding inspection records, the value of w3 is 0.95, otherwise it is 1.

8. The feasibility assessment method for transporting large items across a bridge according to claim 1 is characterized in that: A is 0.95 and B is 1.

2.

9. The feasibility assessment method for transporting large items across a bridge according to claim 1 is characterized in that: The transverse layout rules of the bridge specifically include: the spacing between two prefabricated units of the prefabricated structure takes the maximum value of the applicable range; the transverse layout of the cantilever plate of the box girder and solid plate structure takes the maximum value of the applicable range, and the spacing between the webs of the box girder takes the maximum value of the applicable range.

Images