Methods for controlling the transverse deformation of the bridge deck during the installation of steel-concrete composite girder cable-stayed bridges

Abstract

This invention discloses a method for controlling the transverse deformation of the bridge deck during the installation of a steel-concrete composite girder cable-stayed bridge. The method includes: S1, calculating the lifting posture of the girder segment using the finite element method; S2, lifting the newly lifted girder segment; S3, calculating the web misalignment based on the lifting posture; S4, correcting the web misalignment; S5, tensioning the cables of the newly lifted girder segment to convert its support system; and S6, applying a counterweight load to the newly lifted girder segment until there is no height difference between the newly lifted girder segment and the segment occupied by the bridge crane, and then performing a matching connection of the bridge deck. This invention effectively solves the problem of secondary stress in the bridge deck and steel side box girder web caused by forced deformation in existing technologies, eliminates the risk of bridge deck cracking during matching and connection, improves bridge deck durability, and enhances bridge deck flatness.

Description

Technical Field

[0001] This invention belongs to the technical field of civil engineering, specifically relating to a method for controlling the transverse deformation of the bridge deck during the installation of a steel-concrete composite beam cable-stayed bridge. Background Technology

[0002] The installation of composite beam cable-stayed bridges mainly involves two methods: component assembly and whole-segment hoisting. Component assembly involves dividing the composite beam into steel main beams, diaphragms, bridge decks, etc., which are hoisted separately and then assembled into a complete composite beam. Component assembly is lightweight and easy to transport, making it suitable for bridges in mountainous areas; however, on-site assembly at the bridge site takes a long time. Figure 1 The integral segmental hoisting method involves assembling the individual components of a steel-concrete composite beam into segments in a factory, transporting the segments as a whole to the bridge site, and then hoisting them into place. Integral segmental hoisting is highly efficient, and the primary dead load is borne by the steel-concrete composite section, resulting in lower steel consumption.

[0003] However, due to the heavy weight of the steel-concrete composite beam segments, and the significant weight of the bridge crane used to lift them, the steel-concrete composite beam experiences transverse stress similar to a simply supported beam. Under the combined weight of the bridge crane and the lifting weight of each composite beam segment, the bridge deck and diaphragms of the section occupied by the crane will undergo downward concave deformation, and the steel side box will twist inward. The newly lifted beam segment's support point is at the lifting point, where the stress is similar to that of a cantilever beam, resulting in upward convex deformation under its own weight, and outward twisting of the steel side box. This leads to misalignment in the web of the steel side box of both the newly lifted beam segment and the section occupied by the crane, as well as misalignment in the bridge deck, preventing a smooth fit and connection between the two.

[0004] Existing technologies generally use a combination of jacks and jacks to gradually apply forced displacement to the steel side box web and bridge deck to eliminate misalignment. Although this method can geometrically ensure the matching and connection between the newly lifted beam segment and the beam segment occupied by the bridge deck crane, the forced deformation creates strong secondary stress at the connection between the steel side box and the bridge deck of the two beam segments. In severe cases, this can lead to cracking of the bridge deck and loss of flatness. The secondary stress at the weld W of the steel side box may also impair fatigue life. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned shortcomings in the prior art by providing a method for controlling the transverse deformation of the bridge deck during the installation of a steel-concrete composite beam cable-stayed bridge. This method aims to solve the problem that misalignment exists in the steel side box web of newly lifted beam segments and beam segments occupied by bridge cranes, and that misalignment also exists in the bridge deck, preventing the two from being smoothly matched and connected.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for controlling the transverse deformation of the bridge deck during the installation of a steel-concrete composite beam cable-stayed bridge includes the following steps:

[0008] S1. The lifting posture of the beam segment is calculated using the finite element method.

[0009] S2. Lifting the newly lifted beam segment;

[0010] S3. Calculate the web misalignment based on the lifting posture of the beam segment;

[0011] S4. Correct the web misalignment.

[0012] S5. Tension the cables of the newly lifted beam segment and change the support system of the newly lifted beam segment;

[0013] S6. Apply a counterweight load to the newly lifted beam segment until there is no height difference between the newly lifted beam segment and the beam segment occupied by the bridge deck crane, and then perform bridge deck matching connection.

[0014] Furthermore, step S1 specifically includes:

[0015] S1.1 Using the finite element method with plate and shell elements or solid elements, calculate the attitude of the bridge deck at the front end of the bridge section occupied by the bridge crane under the action of the self-weight P1 of the bridge crane. This attitude includes: the web torsion angle θ. c1 and maximum downward deflection d c1 ;

[0016] S1.2. Using the finite element method with plate and shell elements or solid elements, calculate the attitude of the bridge deck at the front end of the bridge segment occupied by the bridge crane under the combined action of the bridge crane's own weight and the weight of the newly lifted beam segment P2. This attitude includes: the web torsion angle θ. c2 and maximum downward deflection d c2 ;

[0017] S1.3. Using the finite element method with plate and shell elements or solid elements, calculate the attitude of the newly lifted beam segment under its own weight. This attitude includes: the web torsion angle θ. c3 and maximum upward convexity d c3 .

[0018] Further, step S3 calculates the web misalignment as follows:

[0019] d w3 =θ c h1

[0020] θ c =θ c2 +θ c3

[0021] Where, d w3 θ is the maximum misalignment of the web, h1 is the distance from the lower edge of the side box to the torsion center C1, and θ is the maximum misalignment of the web. cThis refers to the relative torsional angle between the side box web of the bridge deck crane-occupied beam segment and the newly lifted beam segment.

[0022] Furthermore, step S4 specifically includes:

[0023] S4.1. Brackets are installed on both sides of the bottom plate of the bridge deck crane occupies the beam segment, and steel strands are threaded through the brackets;

[0024] S4.2 Calculate the tension T of the steel strand in step S4.1;

[0025] S4.3 If the tensile force T is greater than the threshold, then d w3 =1~5mm, recalculate θ c Then return to step S4.2; if the tension T is less than or equal to the threshold, proceed to step S4.4.

[0026] S4.4 Calculate the arching of the bridge deck under the action of tension T of the steel strand;

[0027] S4.5. Adjust the steel strands according to the value of T, correct the web misalignment, and reduce the deformation difference between the newly lifted beam segment and the beam segment occupied by the bridge crane for the first time. At this time, the deflection of the bridge deck of the beam segment occupied by the bridge crane is d. c2 -d c4 , where d c4 This refers to the arching of the bridge deck under tensile force T.

[0028] S4.6 Weld the steel side boxes to complete the matching connection of the steel side boxes.

[0029] Furthermore, in step S4.2, the tensile force T of the steel strand is calculated as follows:

[0030]

[0031] Where L is the span of the diaphragm, L z G is the spacing between the transverse diaphragms, G is the shear modulus of the steel, and E is the shear modulus of the steel. s I is the elastic modulus of steel. 0s For the conversion of the bending moment of inertia of the diaphragm, I d Let be the torsional moment of inertia of the box girder.

[0032] Further, step S4.4 calculates the bridge deck camber under the tension T of the steel strands, including:

[0033] Calculate the deflection equation of the bridge deck arch:

[0034]

[0035] Calculate the maximum deflection of the bridge deck arch:

[0036]

[0037] Where f4(y) is the equation for the anti-arch deflection of the bridge deck, M T2 Let y be the bending moment generated in the transverse diaphragm where the bridge crane occupies the space, and d be the lateral distance from the bridge deck end of the bridge crane occupying beam to the cable anchor point. c4 This refers to the arching of the bridge deck under tensile force T.

[0038] Furthermore, step S5 specifically includes:

[0039] S5.1 Calculate the bending moment M of the weld W between the newly lifted beam segment and the beam segment occupied by the bridge crane, caused by the self-weight of the newly lifted beam segment. b1 :

[0040]

[0041] Where l is the length of the newly hoisted beam segment, and q is the intensity of the beam segment's self-weight load;

[0042] S5.2 After one cable is laid, based on the fact that the weld W between the newly lifted beam segment and the beam segment occupied by the bridge crane is under axial compression, calculate the tension T of one cable. c ;

[0043] S5.3, with T c As a tension cable, the lifting rope Cb of the bridge crane releases the lifting force, transferring the weight of the beam segment from the bridge crane to the cable. This transforms the structural system of the newly lifted beam segment from a cantilever beam to a simply supported beam, and changes the bridge deck curve of the newly lifted beam segment from an upward convexity d. c3 , converted to concave d c5 The support force of the bridge crane is reduced from P2 to P1, and the deflection of the bridge crane-occupied beam segment is reduced from d. c2 -d c4 Reduce to d c1 -d c4 At this time, the deflection difference d between the newly lifted beam segment and the beam segment occupied by the bridge crane is d = d c1 -d c4 -d c5 .

[0044] Further, in step S5.2, the tension T of the cable is calculated. c for:

[0045]

[0046] Where α is the inclination angle of the cable plane, h2 is the distance from the cable anchor point to the centroid of the composite beam, and z1 is the distance from the cable anchor point to the weld W.

[0047] Furthermore, in step S6, a concentrated load Pc is applied using the bridge axis:

[0048]

[0049] Where L1 is the transverse spacing of the cable anchor points.

[0050] Furthermore, in step S6, the weight P of the lifting device is used. c1 Add weight P to the lifting sling c2 The method of applying a compressive load P c Among them, the additional weight P c2 for:

[0051]

[0052] Where 'a' is the distance from the lifting device to the cable anchor point.

[0053] The method for controlling the transverse deformation of the bridge deck during the installation of a steel-concrete composite beam cable-stayed bridge provided by this invention has the following beneficial effects:

[0054] The control method of this invention can be applied to the application of double-sided box girder and PK box girder; specifically, it can adopt a smooth connection between the steel side box and the bridge deck, eliminate the forced deformation of the bridge deck and the steel side box, and avoid the additional stress caused by the forced matching of the bridge deck and cracking caused by the forced matching of the bridge deck.

[0055] The bridge deck of the present invention has no additional deformation of the bridge deck section occupied by the bridge crane and the newly lifted bridge deck section, the bridge deck connection is smooth and the flatness is improved; and the weld is always under pressure during construction, without additional tensile stress, which improves the stress state of the weld and improves fatigue resistance; in addition, the tie rods and tie steel strands of the present invention can be recycled, and the amount of temporary facility materials used is small. Attached Figure Description

[0056] Figure 1 The entire segment is hoisted.

[0057] Figure 2 This describes the stress pattern of the beam segment occupied by the bridge deck crane.

[0058] Figure 3 This refers to the deformation mode of the beam segment occupied by the bridge deck crane.

[0059] Figure 4 This describes the stress pattern of the newly hoisted beam segment.

[0060] Figure 5 This refers to the deformation mode of the newly lifted beam segment.

[0061] Figure 6 The deformation of the beam segment occupied by the front bridge deck crane was caused by the tensioning.

[0062] Figure 7 To achieve basic elimination of torsion in the side box after tension correction, the deflection under the bridge deck is alleviated.

[0063] Figure 8This is a schematic diagram of the welded side of the side box.

[0064] Figure 9 This is a schematic diagram of the front side of the side box welding.

[0065] Figure 10 A schematic elevation view of the cable and support system conversion.

[0066] Figure 11 This involves the transformation of the support system, stress patterns, and deformation of the newly lifted beam segment.

[0067] Figure 12 The stress patterns and deformations of the bridge deck crane's occupancy beam segment support system before and after the conversion.

[0068] Figure 13 The bridge axle ballast scheme.

[0069] Figure 14 For lifting gear and additional counterweight scheme.

[0070] Figure 15 This is a flowchart of the present invention. Detailed Implementation

[0071] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0072] Example 1: The method for controlling the transverse deformation of the bridge deck during the installation of the steel-concrete composite girder cable-stayed bridge in this example is based on... Figure 15 Specifically, it includes the following steps:

[0073] Step S1: Calculate the lifting posture of the beam segment using the finite element method. For details, refer to... Figures 2-5 This step includes the following:

[0074] Step S1.1: Using the finite element method with plate and shell elements or solid elements, calculate the attitude of the bridge deck at the front end of the bridge segment occupied by the bridge crane under the action of the self-weight P1 of the bridge crane. This attitude mainly includes: web torsion angle θ. c1 and maximum downward deflection d c1 ;

[0075] Step S1.2: Using the finite element method with plate and shell elements or solid elements, calculate the attitude of the bridge deck at the front end of the bridge segment occupied by the bridge crane under the combined action of the bridge crane's own weight and the weight of the newly lifted beam segment P2. This attitude mainly includes: the web torsion angle θ. c2 and maximum downward deflection d c2;

[0076] Step S1.3: Using the finite element method with plate and shell elements or solid elements, calculate the attitude of the newly lifted beam segment under its own weight. This attitude mainly includes: the web torsion angle θ. c3 and maximum downward deflection d c3 .

[0077] Step S2: Lift the newly lifted beam segment. Since the web misalignment has been corrected by tie rods, the side box can be welded directly.

[0078] Step S3: Calculate the web misalignment based on the lifting posture of the beam segment. For details, refer to [reference needed]. Figures 2-5 This step includes the following:

[0079] The web misalignment is calculated as follows:

[0080] d w3 =θ c h1

[0081] θ c =θ c2 +θ c3

[0082] Where h1 is the distance from the lower edge of the side box to the torsion center C1.

[0083] Step S4: Correct the web misalignment. For details, refer to [link / reference]. Figure 6 and Figure 7 This step includes the following:

[0084] Step S4.1: Install corbels on both sides of the bottom plate of the bridge deck crane positioning beam segment, and thread steel strands through the corbels;

[0085] Step S4.2: Calculate the tension T of the steel strand in step S4.1:

[0086]

[0087] Where L is the span of the diaphragm, L z G is the spacing between the transverse diaphragms, G is the shear modulus of the steel, and E is the shear modulus of the steel. s I is the elastic modulus of steel. 0s For the conversion of the bending moment of inertia of the diaphragm, I d The torsional moment of inertia of the box girder;

[0088] Step S4.3: If the tensile force T is greater than the threshold, then d w3 =1~5mm, recalculate θ c Then return to step S4.2; if the tension T is less than or equal to the threshold, proceed to step S4.4.

[0089] Step S4.4: Calculate the bridge deck arch under the action of tension T of the steel strand;

[0090] Calculate the deflection equation of the bridge deck arch:

[0091]

[0092] Calculate the maximum deflection of the bridge deck arch:

[0093]

[0094] Step S4.5: Adjust the steel strands according to the value of T, correct the web misalignment, and reduce the deformation difference between the newly lifted beam segment and the beam segment occupied by the bridge crane for the first time. At this time, the deflection of the bridge deck of the beam segment occupied by the bridge crane is d. c2 -d c4 ;

[0095] Step S4.6, Reference Figure 8 and Figure 9 Weld the steel side boxes to complete the matching connection of the steel side boxes.

[0096] Step S5: Tension the cables of the newly lifted beam segment and convert the support system of the new beam segment. For details, refer to [link / reference needed]. Figure 10 and Figure 11 This step includes the following:

[0097] Step S5.1: Calculate the bending moment M of the weld W between the newly lifted beam segment and the beam segment occupied by the bridge crane, caused by the self-weight of the newly lifted beam segment. b1 :

[0098]

[0099] Where l is the length of the newly hoisted beam segment, and q is the intensity of the beam segment's self-weight load;

[0100] Step S5.2: After laying one cable, calculate the cable tension T based on the axial compression state of the weld W between the newly lifted beam segment and the beam segment occupied by the bridge crane. c :

[0101]

[0102] Where α is the inclination angle of the cable plane, h2 is the distance from the cable anchor point to the centroid of the composite beam, and z1 is the distance from the cable anchor point to the weld W;

[0103] Step S5.3, with T c As a tension cable, the lifting rope Cb of the bridge crane releases the lifting force, transferring the weight of the beam segment from the bridge crane to the cable. This transforms the structural system of the newly lifted beam segment from a cantilever beam to a simply supported beam, and changes the bridge deck curve of the newly lifted beam segment from an upwardly convex shape to a maximum downward deflection d. c3, converted to concave d c5 The support force of the bridge crane is reduced from P2 to P1, and the deflection of the bridge crane-occupied beam segment is reduced from d. c2 -d c4 Reduce to d c1 -d c4 At this time, the deflection difference d between the newly lifted beam segment and the beam segment occupied by the bridge crane is d = d c1 -d c4 -d c5 .

[0104] Step S6: Apply a counterweight load to the newly lifted beam segment until there is no height difference between the newly lifted beam segment and the beam segment occupied by the bridge deck crane, and then perform bridge deck matching connection.

[0105] In this embodiment, after the matching and connection of the newly lifted beam segment and the beam segment occupied by the bridge crane are completed, the tie rods and tie steel strands can be removed and transferred to the next beam segment for matching.

[0106] Specifically, the counterweight load Pc in this embodiment has two application schemes;

[0107] Option 1:

[0108] refer to Figure 12 A concentrated load Pc is applied using the bridge axis:

[0109]

[0110] Where L1 is the transverse spacing of the cable anchor points.

[0111] Option 2:

[0112] refer to Figure 13 The weight P of the lifting device is used. c1 Add weight P to the lifting sling c2 The method of applying a compressive load P c Among them, the additional weight P c2 for:

[0113]

[0114] Where 'a' is the distance from the lifting device to the cable anchor point.

[0115] refer to Figures 2-15This invention uses the finite element method to calculate and determine the posture of the bridge deck crane-positioned beam segment under the action of the bridge deck crane's self-weight P1, the bridge deck crane's self-weight, and the weight of the newly lifted beam segment P2. The posture of the newly lifted beam segment under its own weight is calculated; the new beam segment is lifted; the web misalignment is calculated, and the web misalignment is corrected by applying tensile force to achieve the welded connection of the steel side box. Simultaneously, the deformation difference between the newly lifted beam segment and the bridge deck crane-positioned beam segment is reduced for the first time; one cable is laid for the newly lifted beam segment, the support system is changed, and the second... The invention reduces the deformation difference between the newly lifted beam segment and the beam segment occupied by the bridge crane; it applies weight to the newly lifted beam segment to increase its concave deformation and eliminate the deformation of the bridge deck of the newly lifted beam segment and the beam segment occupied by the bridge crane; it completes the matching and connection of the bridge deck of the newly lifted beam segment and the beam segment occupied by the bridge crane; it removes the tie rods and tie steel strands for reuse in the next beam segment; the invention uses the above methods to solve the secondary stress in the bridge deck and steel side box web caused by forced deformation in the prior art, eliminates the risk of bridge deck cracking during matching and connection, improves bridge deck durability, and enhances bridge deck flatness.

[0116] Although specific embodiments of the invention have been described in detail with reference to the accompanying drawings, this should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by a person skilled in the art without inventive effort within the scope described in the claims still fall within the scope of protection of this patent.

Claims

1. A method for controlling the transverse deformation of the bridge deck during the installation of a steel-concrete composite beam cable-stayed bridge, characterized in that, Includes the following steps: S1. The lifting posture of the beam segment is calculated using the finite element method. S2. Lifting the newly lifted beam segment; S3. Calculate the web misalignment based on the lifting posture of the beam segment; S4. Correct the web misalignment. S5. Tension the cables of the newly lifted beam segment and change the support system of the newly lifted beam segment; S6. Apply a counterweight load to the newly lifted beam segment until there is no height difference between the newly lifted beam segment and the beam segment occupied by the bridge deck crane, and then perform bridge deck matching connection. Step S1 specifically includes: S1.1 Using the finite element method with plate and shell elements or solid elements, calculate the attitude of the bridge deck at the front end of the bridge section occupied by the bridge crane under the action of the self-weight P1 of the bridge crane. This attitude includes: web torsion angle. θ c1 and maximum deflection d c1 ; S1.

2. Using the finite element method with plate and shell elements or solid elements, calculate the attitude of the bridge deck at the front end of the bridge segment occupied by the bridge crane under the combined action of the bridge crane's own weight and the weight of the newly lifted beam segment, P2. This attitude includes: web torsion angle. θ c2 and maximum deflection d c2 ; S1.

3. Using the finite element method with plate and shell elements or solid elements, calculate the attitude of the newly lifted beam segment under its own weight. This attitude includes: web torsion angle. θ c3 and maximum convexity d c3 ; The web misalignment is calculated in step S3 as follows: in, This represents the maximum misalignment of the web. h 1 represents the distance from the lower edge of the side box to the center of torsion C1. The relative torsional angle between the side box web of the bridge deck crane-occupied beam segment and the newly lifted beam segment; Step S4 specifically includes: S4.

1. Brackets are installed on both sides of the bottom plate of the bridge deck crane occupies the beam segment, and steel strands are threaded through the brackets; S4.2 Calculate the tension T of the steel strand in step S4.1; S4.3 If the tensile force T is greater than the threshold, then d w3 =1~5mm, recalculate θ c Then return to step S4.2; if the tension T is less than or equal to the threshold, proceed to step S4.

4. S4.4 Calculation of bridge deck arching under tension T of steel strands d c4 ; S4.

5. Adjust the steel strands according to the value of T, correct the web misalignment, and reduce the deformation difference between the newly lifted beam segment and the bridge deck section occupied by the bridge crane for the first time. At this time, the deflection of the bridge deck section occupied by the bridge crane is... d c2 - d c4 ,in, d c4 This refers to the arching of the bridge deck under tensile force T. S4.6 Weld the steel side boxes to complete the matching connection of the steel side boxes; In step S4.2, the tensile force T of the steel strand is calculated as follows: in, L For the span of the diaphragm, L z The spacing between the horizontal diaphragms. G Shear modulus of steel E s The elastic modulus of steel, I 0s To calculate the bending moment of inertia of the diaphragm, I d The torsional moment of inertia of the box girder; In step S4.4, the tension in the steel strand is calculated. T Bridge deck arching under action includes: Calculate the deflection equation of the bridge deck arch: Calculate the maximum deflection of the bridge deck arch: in, The equation for the inverted arch deflection of the bridge deck is given. The bending moment generated in the diaphragm where the bridge crane occupies space. This refers to the lateral distance between the bridge deck panel at the beam end where the bridge crane is positioned and the anchor point of the cable. This refers to the arching of the bridge deck under tensile force T. Step S5 specifically includes: S5.1 Calculate the bending moment W of the weld between the newly lifted beam segment and the beam segment occupied by the bridge crane, caused by the self-weight of the newly lifted beam segment. M b1 : in, l The length of the newly hoisted beam segment. q The intensity of the beam segment's self-weight load; S5.2 After one cable is laid, calculate the tension of one cable based on the fact that the weld W between the newly lifted beam segment and the beam segment occupied by the bridge crane is under axial compression. ; S5.3, with As a tension cable, the lifting rope Cb of the bridge crane releases the lifting force, transferring the weight of the beam segment from the bridge crane to the cable. This transforms the structural system of the newly lifted beam segment from a cantilever beam to a simply supported beam, and changes the bridge deck curve of the newly lifted beam segment from an upward convex shape. d c3 Converted to concave d c5 The support force of the bridge crane was reduced from P2 to P1, and the deflection of the bridge crane's occupied beam segment was reduced from... d c2 - d c4 Reduce to d c1 - d c4 At this time, the deflection difference d between the newly lifted beam segment and the beam segment occupied by the bridge crane is d= d c1 - d c4 - d c5 ; In step S5.2, the tension of the cable is calculated. for: in, α The inclination angle of the cable face. h 2 represents the distance from the cable anchor point to the centroid of the composite beam. z 1 represents the distance from the cable anchor point to the weld W; In step S6, a concentrated force along the bridge axis is used to apply a compressive load Pc. in, L 1 represents the transverse spacing of the cable anchor points; In step S6, the weight P of the lifting device is used. c1 Add weight P to the lifting sling c2 The method of applying a compressive load P c Among them, the additional weight P c2 for: Where 'a' is the distance from the lifting device to the cable anchor point.

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