A temporary pier setting position optimization method based on beam body assembly cumulative error

Abstract

The application discloses a temporary pier setting position optimization method based on beam body assembling cumulative error, which establishes a balance equation matrix through a force method and a displacement method, establishes a corner calculation model of a jacking multi-span, adjusts and optimizes the position of the initially drafted temporary pier through the corner calculation model, so that the corner theta 1 at the starting position of the first span is minimum, and then the cumulative error in the beam body assembling process is minimum. The application has high operation convenience, can automatically adjust and optimize the position of the temporary pier through the constructed corner calculation model, provides a basis for the beam body assembling construction, and has good economic practicality after optimization, can reasonably set the temporary pier position and quantity, avoids the waste of financial and material resources, effectively reduces the beam body assembling error and deformation, avoids the secondary stress of the beam body, makes the whole beam body bear stress well, has a long service life, high safety, good practicality and wide application prospect.

Description

Technical Field

[0001] This invention relates to a method for optimizing the location of temporary piers based on the cumulative error of beam assembly, belonging to the field of bridge construction technology. Background Technology

[0002] During the incremental launching construction, the negative bending moment of the beam at each support point is proportional to the square of the span. If the bridge span increases, the internal forces of the bridge will increase sharply. Given the limited cross-section of the steel beam, it is necessary to study the reasonable segment length for incremental launching. Setting temporary piers is an effective method to increase the applicable span of the incremental launching method. Therefore, the reasonable segment length for incremental launching is closely related to the setting of temporary piers. Temporary piers are placed between two permanent piers of the bridge, dividing one span of a large-span bridge into two or more spans, which can reduce the span of the bridge, thereby correspondingly reducing the internal forces of the main beam. For steel beam bridges constructed by incremental launching, a segmented assembly and incremental launching method is generally adopted. Due to the uncertainty of construction influencing factors, during the assembly of steel beam segments, the actual joints of successively assembled segments and the pre-set joints of successively assembled segments will continuously have the same deflection angle. This results in a difference in the length of the upper and lower edges of the beam after each subsequent segment assembly, and this difference increases with the number of assembled segments. Once all segments are assembled, the difference in length between the upper and lower edges of the beam accumulates to a relatively large value. This causes deformation in the vertical plane. After the beam is jacked into place, it is leveled according to design requirements. At this point, the deformation caused by assembly errors generates secondary stresses in the beam. These secondary stresses, resulting from the accumulation of assembly errors, negatively impact the overall load-bearing capacity of the beam. To minimize these accumulated assembly errors, and considering the significant cost and resources required for constructing temporary piers, the proper design of temporary piers becomes crucial. Summary of the Invention

[0003] Therefore, the purpose of this invention is to provide a method for optimizing the location of temporary piers based on the cumulative error of beam assembly, which can solve the problem that the cumulative error of beam assembly during the jacking construction process is unfavorable to the beam and overcome the shortcomings of the prior art.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A method for optimizing the location of temporary piers based on the cumulative error of beam assembly is proposed. By establishing a rotation angle calculation model for multi-span jacking, the location of the initially proposed temporary piers is adjusted and optimized to minimize the rotation angle θ1 at the starting position of the first span, thereby minimizing the cumulative error during beam assembly.

[0006] The aforementioned optimization method specifically includes the following steps:

[0007] Step 1: Establish the equilibrium equation matrix using the force method and displacement method;

[0008] Step 2: Establish corner calculation models for jacking two-span, three-span, and multi-span structures, and adjust and optimize the positions of the initially proposed temporary piers.

[0009] In step 1 above, the equilibrium equation matrix of the temporary piers at each support point is established, as follows:

[0010]

[0011] in the formula EI is the main beam stiffness; θ j Let be the rotation angle of the beam section at temporary pier j (j = 1, 2, ..., n); q is the weight per unit length of the main beam.

[0012] In step 2, a rotation angle calculation model is established based on the equilibrium equation matrix:

[0013] Two spans:

[0014] Three spans:

[0015] ...

[0016] n spans time:

[0017] In the formula, q is the weight per unit length of the main beam; θ1 is the rotation angle at the starting position of the first span of the jacking; EI is the stiffness of the main beam; l k (k = 1, 2, ..., n-1) is the pushing length.

[0018] In step 2 above, the specific steps for adjusting and optimizing the initially proposed location of the temporary pier are as follows:

[0019] a. Based on engineering data, site survey, and bridge span layout, a preliminary jacking scheme for the placement of temporary piers is determined.

[0020] This includes preset values ​​for the number of jacking spans and the jacking length;

[0021] b. Calculate the preset rotation angle θ1 at the starting position of the first span when jacking two spans using the rotation angle calculation model based on the preset value of the jacking length. When the preset rotation angle θ1 of the two spans is large, adjust and optimize the preset value of jacking to minimize the rotation angle θ1 at the starting position of the first span, and obtain the corrected jacking lengths L1 and L2.

[0022] c. Calculate the rotation angle θ1 at the starting position of the first span when jacking three spans using the rotation angle calculation model based on the jacking correction lengths l1 and l2. When the rotation angle θ1 of the three spans is large, adjust the jacking lengths again and perform secondary adjustment and optimization correction. Select the jacking lengths L1, L2, and L3 for secondary correction.

[0023] d. Continuing in this manner, the optimal values ​​of θ1 are obtained when jacking four spans, five spans, ..., n-1 spans, until a pre-defined reasonable jacking length L1, L2, L3, ... L is selected. n-1 ;

[0024] e. Replace the initially determined jacking scheme with the selected reasonable jacking length.

[0025] In the corner calculation model, set the corner optimization range value θ'1 at the starting position of the first span when pushing two, three, four, ... n-1 spans. Compare the calculated values ​​of θ1 for the two, three, ... n-1 spans. If the calculated value of θ1 is greater than the optimization range value θ'1, adjust the pushing length and calculate again until the calculated value of θ1 is less than or equal to the optimization range value θ'1.

[0026] For the two spans mentioned above, the optimal range value θ'1 of the turning angle at the starting position of the first span is 0; for the three spans, four spans, ... n-1 spans, the corresponding optimal range value θ'1 of the turning angle is determined based on engineering data, on-site survey, and the preset number of launching spans and launching length.

[0027] The specific steps in the aforementioned step bd include:

[0028] In step b, based on the preset values ​​of the jacking lengths for the two spans, θ1 and the ratio of the jacking lengths l1 / l2 for the two spans are calculated using the rotation calculation model. The preset jacking values ​​are then adjusted and optimized until the rotation angle θ1 at the starting position of the first span is 0, yielding the corrected jacking lengths L1 and L2. Finally, the corrected jacking length L3 for the third span is calculated using the following formula:

[0029] L3 = Sum of the preset lengths of the three spans - Sum of the corrected lengths of the two spans.

[0030] In step c, based on the corrected lengths L1, L2, and L3 obtained in step b, θ1 is calculated again using the angle calculation model. θ1 is then compared with the corresponding optimization range value θ'1, and the corrected lengths L1, L2, and L3 are adjusted and optimized a second time until the angle θ1 at the starting position of the first span is no greater than the optimization range value. Finally, the corrected length for pushing the fourth span L4 is calculated using the following formula:

[0031] L4 = Sum of the preset lengths of the four spans - Sum of the corrected lengths of the three spans.

[0032] In step d, the optimized values ​​of θ1 for jacking four spans, five spans, ..., n-1 spans are obtained sequentially. Preset reasonable jacking lengths L1, L2, L3, ..., Ln-2 are selected, and the jacking length L for the (n-1)th span is calculated. n-1 The correction length is calculated using the following formula:

[0033] L n-1= (n-1) sum of lengths across preset values ​​- (n-2) sum of lengths across modified values.

[0034] Compared with existing technologies, this invention discloses a method for optimizing the location of temporary piers based on the cumulative error of beam assembly. It establishes an equilibrium equation matrix using force and displacement methods, and builds a rotation angle calculation model for multi-span jacking. This model adjusts and optimizes the initially proposed temporary pier locations, minimizing the rotation angle θ1 at the starting position of the first span, thereby minimizing the cumulative error during beam assembly. Compared with conventional empirical design methods, this invention, through its constructed rotation angle calculation model, can automatically adjust and optimize the location of temporary piers, providing a basis for beam assembly work. It can adjust and optimize the initially proposed temporary pier locations to obtain a reasonable number of jacking spans and jacking length, significantly reducing the cumulative error of beam assembly.

[0035] The beneficial effects of this invention are:

[0036] This invention is highly convenient to operate. The corner calculation model can automatically adjust and optimize the position of temporary piers. It can not only reasonably set the position and number of temporary piers, avoiding too many or too few temporary piers and avoiding waste of financial and material resources, but also effectively reduce beam assembly errors and deformation, thereby avoiding secondary stress in the beam, making the entire beam have good stress distribution, long service life, and high safety. It has good practicality and promotion prospects.

[0037] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will now be described in further detail with reference to the accompanying drawings, wherein:

[0039] Figure 1 This is a schematic diagram of the arrangement of temporary piers according to the present invention;

[0040] Figure 2 for Figure 1 A simplified model;

[0041] Figure 3 A simplified model for pushing two spans;

[0042] Figure 4 This is a simplified model of a three-span top-pushing system. Detailed Implementation

[0043] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the preferred embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0044] like Figures 1-2 As shown, a method for optimizing the location of temporary piers based on the cumulative error of beam assembly is proposed. This method establishes a rotation angle calculation model for multi-span jacking and optimizes the initially proposed location of temporary piers to minimize the rotation angle θ1 at the starting position of the first span, thereby minimizing the cumulative error during beam assembly.

[0045] Specifically, it includes the following steps:

[0046] Step 1: Establish the equilibrium equation matrix using the force method and displacement method;

[0047] Step 2: Establish corner calculation models for jacking two-span, three-span, and multi-span structures, and adjust and optimize the positions of the initially proposed temporary piers.

[0048] In step 1, the schematic diagram of the temporary pier layout is shown below. Figure 1 and Figure 2 According to the displacement method in structural mechanics, the equilibrium equations at temporary piers 1 and n are:

[0049] Temporary pier 1:

[0050] Temporary pier n:

[0051] In the formula, l0 is the cantilever of the front section of temporary pier 1, l x For the cantilever of the rear section of the temporary pier n, since l0 is very small relative to l1, l x relative to l n-1 It is also very small, so equations (1) and (2) can be simplified as follows:

[0052]

[0053]

[0054] The equilibrium equations for the remaining points are as follows:

[0055] Temporary pier 2:

[0056] Temporary pier 3:

[0057] ...

[0058] Temporary pier n-1:

[0059] The equilibrium equation matrix can be constructed using the equilibrium equations at the above points, and is expressed as follows:

[0060]

[0061] in the formula EI is the main beam stiffness; θ j q is the rotation angle of the beam section at support j (j = 1, 2, ..., n); q is the weight per unit length of the main beam.

[0062] In step 2, a rotation angle calculation model is established based on the equilibrium equation matrix:

[0063] Two spans:

[0064] Three spans:

[0065] ...

[0066] n spans time:

[0067] In the formula, q is the weight per unit length of the main beam; θ1 is the rotation angle at the starting position of the first span of the jacking; EI is the stiffness of the main beam; l k (k = 1, 2, ..., n-1) represents the pushing length.

[0068] Step 2 involves adjusting and optimizing the initially proposed location of the temporary piers as follows:

[0069] a. Based on engineering data, site survey, and bridge span layout, a preliminary jacking scheme for the placement of temporary piers is determined.

[0070] This includes preset values ​​for the number of jacking spans and the jacking length;

[0071] b. Calculate the preset rotation angle θ1 at the starting position of the first span when jacking two spans using the rotation angle calculation model based on the preset value of the jacking length. When the preset rotation angle θ1 of the two spans is large, adjust and optimize the preset value of jacking to minimize the rotation angle θ1 at the starting position of the first span, and obtain the corrected jacking lengths L1 and L2.

[0072] c. Calculate the rotation angle θ1 at the starting position of the first span when jacking three spans using the rotation angle calculation model based on the jacking correction lengths l1 and l2. When the rotation angle θ1 of the three spans is large, adjust the jacking lengths again and perform secondary adjustment and optimization correction. Select the jacking lengths L1, L2, and L3 for secondary correction.

[0073] d. Continuing in this manner, the optimal values ​​of θ1 are obtained when jacking four spans, five spans, ... n spans, until a pre-defined reasonable jacking length L1, L2, L3, ... L is selected. n-1 ;

[0074] e. Replace the initially determined jacking scheme with the selected reasonable jacking length.

[0075] Preferably, in the corner calculation model, an optimized corner range value θ'1 is set at the starting position of the first span corresponding to the jacking of two spans, three spans, four spans...n-1 spans. The calculated values ​​of θ1 corresponding to two spans, three spans,...n-1 spans are compared. If the calculated value of θ1 is greater than the optimized range value θ'1, the jacking length is adjusted and the calculation is performed again until the calculated value of θ1 is less than or equal to the optimized range value θ'1.

[0076] The optimal range value θ'1 of the turning angle at the starting position of the first span when there are two spans is 0; the corresponding optimal range value θ'1 of the turning angle when there are three spans, four spans, ... n-1 spans is determined according to engineering data, on-site survey and preset number of jacking spans and jacking length.

[0077] In step bd, the specific steps include:

[0078] In step b, based on the preset values ​​of the jacking lengths for the two spans, θ1 and the ratio of the jacking lengths l1 / l2 for the two spans are calculated using the rotation calculation model. The preset jacking values ​​are then adjusted and optimized until the rotation angle θ1 at the starting position of the first span is 0, yielding the corrected jacking lengths L1 and L2. Finally, the corrected jacking length L3 for the third span is calculated using the following formula:

[0079] L3 = Sum of the preset lengths of the three spans - Sum of the corrected lengths of the two spans.

[0080] In step c, based on the corrected lengths L1, L2, and L3 obtained in step b, θ1 is calculated again using the angle calculation model. θ1 is then compared with the corresponding optimization range value θ'1, and the corrected lengths L1, L2, and L3 are adjusted and optimized a second time until the angle θ1 at the starting position of the first span is no greater than the optimization range value. Finally, the corrected length for pushing the fourth span L4 is calculated using the following formula:

[0081] L4 = Sum of the preset lengths of the four spans - Sum of the corrected lengths of the three spans.

[0082] In step d, the optimized values ​​of θ1 for jacking four spans, five spans, ... n spans are obtained sequentially, and the preset reasonable jacking lengths L1, L2, L3, ... L are selected. n-2 And calculate the (n-1)th span L of the push. n-1 The correction length is calculated using the following formula:

[0083] L n-1 = (n-1) sum of lengths across preset values ​​- (n-2) sum of lengths across modified values.

[0084] The jacking construction scheme adopts a jacking length of 40m+28.5m+28.5m+36m+40m+40m+40m.

[0085] When n=3, this is the case of pushing the two spans together, such as... Figure 3 As shown.

[0086] Let θ1 = 0 in equation (9), we get l1 / l2 = 0.618, while in reality l1 / l2 = 1.404 and θ1 = 1606q / EI, which is relatively large, indicating that the actual jacking length is unreasonable. After multiple corrections through the angle calculation model, l1 = 20m, we get l2 = 32.36m, which makes θ1 = 0. At this time, l3 = 20m + 20m + 57m - 20m - 32.36m = 44.64m.

[0087] When n=4, this is the top-push three-span configuration, such as... Figure 4 As shown.

[0088] Substituting the actual jacking length into equation (10), we get θ1 = 1697q / EI, which is relatively large. Substituting l1 = 20m, l2 = 32.36m, l3 = 44.64m into equation (10), we get θ1 = 1796q / EI, which is also relatively large. The jacking length at this time is also unreasonable. After multiple corrections through the angle calculation model, we selected L1 = 20m, L2 = 38m, L3 = 39m. Substituting them into equation (9), we get θ1 = -118.3q / EI. Substituting them into equation (10), we get θ1 = 62.2q / EI.

[0089] Similarly, the optimized values ​​of θ1 for the four, five, six, and seven spans can be obtained, which will not be elaborated further. If the jacking is carried out according to 20m+38m+39m+36m+40m+40m+40m, the comparison between the calculated θ1 and the θ1 of the actual jacking situation is shown in Table 1.

[0090] Table 1 Comparison of θ1 between the optimized jacking length and the actual jacking length

[0091]

[0092] Comparing θ1 under the two jacking lengths, the optimized θ1 is reduced to 7.4% of the original value for two spans, and at most to 1.1%. Therefore, only the construction sequence of piers #1 and #2 needs to be changed, and the position of temporary pier L1 needs to be rearranged. The positions of temporary piers L2, L3, and L4 can remain unchanged. Thus, through the reasonable arrangement of the temporary pier positions, the reasonable jacking segment length is obtained as 20m+38m+39m+36m+40m+40m+40m.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments without departing from the technical solution of the present invention and based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for optimizing the location of temporary piers based on cumulative errors in beam assembly, characterized in that, By establishing a rotation angle calculation model for multi-span jacking, the positions of the initially planned temporary piers are adjusted and optimized to minimize the rotation angle θ1 at the starting position of the first span, thereby minimizing the cumulative error during beam assembly. The specific steps include: Step 1: Establish the equilibrium equation matrix using the force method and displacement method; Step 2: Establish corner calculation models for jacking two-span, three-span, and multi-span structures, and adjust and optimize the positions of the initially proposed temporary piers; In step 1, the equilibrium equation matrix of the temporary piers at each support point is established, as follows: (8) In step 2, a rotation angle calculation model is established based on the equilibrium equation matrix: Two spans: (9) Three spans: (10) …… n spans time: (11) In the formula, (k=1, 2, ..., n-1), EI is the main beam stiffness; l k (k=1, 2, ..., n-1) is the pushing length; θ j θ is the rotation angle of the beam section at temporary pier j (j=1,2,…,n); θ1 is the rotation angle at the starting position of the first span of the jacking; q is the weight per unit length of the main beam.

2. The method for optimizing the location of temporary piers based on the cumulative error of beam assembly according to claim 1, characterized in that, Step 2 involves adjusting and optimizing the initially proposed location of the temporary piers as follows: a. Based on engineering data, site surveys, and bridge span layout, a preliminary jacking scheme for the placement of temporary piers is determined. This includes preset values ​​for the number of jacking spans and the jacking length; b. Based on the preset jacking length, the preset rotation angle θ1 at the starting position of the first span is calculated using the rotation angle calculation model when jacking two spans. When the preset rotation angle θ1 for both spans is large, the preset jacking value is adjusted and optimized to minimize the rotation angle θ1 at the starting position of the first span, thus obtaining the corrected jacking length. L 1. L 2; c. Adjust the length according to the jacking length l 1. l 2. Calculate the rotation angle θ1 at the starting position of the first span when jacking three spans using the rotation angle calculation model. When the rotation angle θ1 of the three spans is large, adjust the jacking length again and perform a second adjustment and optimization correction. Select the jacking lengths L1, L2, and L3 for the second correction. d.By analogy, the optimized value of θ1 for the jacking four-span, five-span, … n-1 span is obtained in turn until the preset reasonable jacking lengths L1, L2, L3, … Ln are selected n-1 ; e. Replace the initially determined jacking scheme with the selected reasonable jacking length.

3. The method for optimizing the location of temporary piers based on the cumulative error of beam assembly according to claim 2, characterized in that, In the corner calculation model, the corner optimization range value at the starting position of the first span is set when jacking two, three, four...n-1 spans. The calculated θ1 values ​​for two spans, three spans, ..., n-1 spans are compared. If the calculated θ1 value is greater than the optimization range value... If the jacking length is adjusted, the calculation is repeated until the calculated value of θ1 is less than or equal to the optimized range value. .

4. The method for optimizing the location of temporary piers based on the cumulative error of beam assembly according to claim 3, characterized in that, The optimized range of the turning angle at the starting position of the first span of the two spans. The value is 0; the corresponding corner optimization range value for three-span, four-span, ... n-1-span spans. The number of jacking spans and the jacking length are determined based on engineering data, on-site surveys, and pre-set jacking data.

5. The method for optimizing the location of temporary piers based on the cumulative error of beam assembly according to claim 4, characterized in that, In step bd, the specific steps include: In step b, based on the preset values ​​of the jacking lengths of the two spans, θ1 and the jacking lengths of the two spans are calculated using the rotation calculation model. l 1 / l The ratio is 2, and the jacking preset value is adjusted and optimized until the turning angle θ1 at the starting position of the first span is 0, thus obtaining the corrected jacking length. L 1. L 2. Calculate the corrected length of the third span L3 during the jacking operation. The calculation formula is as follows: L3 = Sum of the preset lengths of the three spans - Sum of the corrected lengths of the two spans; In step c, the corrected length obtained in step b is used. L 1. L 2. L3, calculate θ1 again using the angle calculation model, and compare θ1 with the corresponding optimization range value. Comparison, for the corrected length L 1. L 2. L3 is adjusted and optimized a second time until the turning angle θ1 at the starting position of the first span is no greater than the optimization range value. And calculate the corrected length of the fourth span L4 of the pusher, the calculation formula is: L4 = Sum of the preset lengths of the four spans - Sum of the corrected lengths of the three spans; In step d, the optimized values ​​of θ1 for jacking four spans, five spans, ..., n-1 spans are obtained sequentially. Preset reasonable jacking lengths L1, L2, L3, ..., Ln-2 are selected, and the jacking length L for the (n-1)th span is calculated. n-1 The correction length is calculated using the following formula: L n-1 = (n-1) Sum of lengths across preset values ​​- (n-2) Sum of lengths across modified values.

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