General construction procedure of cable-stayed-cable suspension cooperative system bridge

Abstract

This invention discloses an overall construction procedure for a cable-stayed-suspension bridge system, relating to the field of bridge construction technology, and aims to solve the technical problem of long construction periods caused by the existing construction procedures used in cable-stayed-suspension bridge systems. The invention includes the following steps: Step 1: Construction of bridge towers and anchorages; Step 2: Cantilever assembly of steel beams in the cable-stayed zone and simultaneous construction of the main cable; Step 3: Erection of stiffening beams in the suspension zone, with n stiffening beam segments erected in the main span, followed by cross-erection of beam segments in the side and middle spans; Step 4: Tensioning of limiting cables; Step 5: Erection of the main beams in the cross-suspension zone, with temporary ties for cable tensioning; Step 6: Erection of the closure section; Step 7: Welding of steel beams in the suspension zone and secondary construction. This invention has advantages such as shortening the construction period and reducing costs.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction technology, specifically relating to the overall construction procedures of a cable-stayed-suspension bridge system. Background Technology

[0002] There are three main types of cable-stayed bridges: cable-stayed bridges, suspension bridges, and cable-stayed-suspension combined systems. Among them, cable-stayed bridges have high stiffness and are suitable for heavy loads, but their span is limited due to the influence of the strength of the main girder and towers. Suspension bridges have large spans, but their stiffness is relatively low. In suspension bridges, the anchorage is a key load-bearing component, resulting in a large amount of anchorage engineering and high costs. Cable-stayed-suspension combined systems effectively integrate the stiffness advantages of cable-stayed bridges and the span potential of suspension bridges through structural complementarity and synergy, achieving larger spans, higher stiffness, and economy.

[0003] Currently, cable-stayed bridges with coordinated cable-stayed systems that are already open to traffic or have completed their main construction, both domestically and internationally, such as the Bosphorus Strait Bridge No. 3, the Tongling Yangtze River Highway-Railway Bridge, and the Tengzhou Xunjiang Bridge, typically follow a construction sequence of: foundation construction, simultaneous construction of anchorages and bridge towers, simultaneous construction of main cables and main beams in the cable-stayed zone, steel beam hoisting in the suspension zone, steel beam closure, welding construction in the suspension zone, and secondary ancillary construction. The sequence of foundation construction followed by simultaneous construction of anchorages and bridge towers is undisputed. The main cables and cable-stayed sections can be constructed either simultaneously or asynchronously. Asynchronous construction can involve either erecting the main cables first and then installing the main beams in the cable-stayed zone, or vice versa. Furthermore, the steel beam hoisting in the suspension zone, the steel beam construction in the intersection area, and the steel beam closure all occupy significant portion of the main construction period and are key areas for scheme optimization and adjustment. A reasonable arrangement of these procedures can effectively save resources and time. Summary of the Invention

[0004] In view of this, the present invention discloses an overall construction procedure for a cable-stayed-suspension bridge system, which aims to solve the technical problem that the construction procedure used in existing cable-stayed-suspension bridge systems results in a long construction period.

[0005] To solve the aforementioned technical problems, the present invention adopts the following technical solution:

[0006] The overall construction procedure for a cable-stayed-suspension bridge system includes the following steps:

[0007] Step 1: Construction of bridge towers and anchorages;

[0008] Step 2: Simultaneous construction of the cantilevered steel beams and main cables in the cable-stayed zone;

[0009] Step 3: Construction of stiffening girder hoisting in the suspension zone. After hoisting n stiffening girder segments in the main span, the side span and middle span girder segments are hoisted in a cross manner.

[0010] Step 4: Tensioning of the limiting slings;

[0011] Step 5: Hoist the main beam in the intersection area and set up temporary ties for sling tensioning;

[0012] Step 6: Hoisting of the closure section;

[0013] Step 7: Welding of steel beams in the suspension zone and second-phase construction.

[0014] In this invention, two bridge towers are provided. The construction of the bridge towers and anchorages is carried out first, following the same procedures as existing bridge construction. For the construction of the cable-stayed section and main cable, synchronous or asynchronous construction can be adopted. Asynchronous construction can involve erecting the main cable first, followed by the main beam of the cable-stayed section, or vice versa. Obviously, synchronous construction will save time, and this invention adopts synchronous construction. As the beam segment is hoisted, the pressure on the saddle increases, and the friction and jacking force also increase accordingly. In the empty cable state, the saddle deflects towards the side span, and during the beam segment erection stage... The earlier the main span is jacked up and reset, the better. Therefore, in this invention, the main span stiffening girder is hoisted first, so that the saddle is jacked up towards the main span to release the longitudinal shear force transmitted by the saddle to the bridge tower. This shear force is generated due to the imbalance of cable force between the main cable in the middle span and the main cable in the side span. Therefore, by cross-hoisting the girder segments in the side span and the middle span, the stiffening girder segments hoisted in the main span can be balanced. For the suspension area of ​​the side span, it can be hoisted from the anchorage side to the bridge tower side, or it can be installed from the bridge tower side to the anchorage side. There is not much difference between the two methods, only the jacking amount of the saddle is determined differently. In actual implementation, it can be selected according to the site conditions.

[0015] Preferably, in step 3, n is 24.

[0016] Furthermore, step 3 specifically includes the following steps:

[0017] Step 3.1: The stiffening girders in the suspension zone are hoisted using a cable-stayed crane, with the main span's 24 stiffening girder sections being hoisted first;

[0018] Step 3.2: After the 24 main span stiffening beams are hoisted, a side span beam segment is hoisted first, followed by a middle span beam segment. The alternating hoisting of side span beam segments and middle span beam segments is repeated until the non-closure segment of the suspension zone stiffening beam is hoisted.

[0019] In this invention, the installation of the stiffening girder in the suspension zone can adopt a hoisting method that combines multiple segments into a large segment, which can significantly save the main line construction period. The cable-mounted crane can be designed to have the hoisting capacity of multiple segments into a large segment.

[0020] Furthermore, in step 4, the tensioning direction of the limiting cable is from the bridge tower towards the anchor span.

[0021] Furthermore, step 5 specifically includes the following steps:

[0022] Step 5.1: Use a cable-mounted crane to hoist the main beam in the intersection area;

[0023] Step 5.2: Set temporary slings on the rear connecting beam of the section to be lifted, and advance by cyclically tensioning multiple pairs of temporary slings. During the lifting of the steel beam, gradually install permanent slings in the intersection area.

[0024] In this invention, the hoisting of the main girder in the cross-section area can currently be carried out using either a bridge deck crane or a cable-stayed crane. When using a bridge deck crane to install the main girder in the cross-section area, it can be considered an extension of the main girder in the cable-stayed section, and the same installation method is used as for the cable-stayed section, allowing the bridge deck crane to be removed in advance. Therefore, the installation of the main girder in the cross-section area using this method occurs before the installation of the stiffening girder in the suspension section. However, in this invention, the main girder in the cross-section area is longer and heavier, forcing the use of a bridge deck crane with higher performance, leading to construction... Increased investment is required. If a cable-mounted crane is used for installation, given the large span of the suspension zone of this bridge, reaching the kilometer level, if the main beam of the cross zone is hoisted before the stiffening girder of the suspension zone is installed, the suspension zone will not have formed gravity stiffness. Under the influence of wind load and temperature, the static and dynamic displacement of the stiffening girder of the suspension zone will be large, which will increase the burden on the long cantilever of the main beam of the cable-stayed zone. At the same time, some temporary slings pulled on the main cable may collide with the cable stays. Therefore, if a cable-mounted crane is used to hoist the main beam of the cross zone, it must be done after the stiffening girder of the suspension zone is installed.

[0025] Preferably, the closure in step 6 adopts one of the following schemes: mid-span closure, suspension zone end closure, intersection zone closure, or cable-stayed zone cantilever end closure.

[0026] Preferably, the closure segment in step 6 is located at the end of the suspension zone.

[0027] In this invention, the suspension zone end closure is adopted, and the stiffening girder is hoisted from the mid-span to the bridge tower. The closure joint has a height difference of 0.1m and a path difference of 0.02m under the longitudinal unconstrained design temperature. The closure joint is hinged. The hinge point of the closure joint is subjected to a vertical shear force of 254.5kN. The interference between the cable-stayed and suspension systems is small, and the error identification is easy. The closure joint is connected after the tensioning is completed and the cross-section is hoisted. Therefore, the closure section is set at the end of the suspension zone.

[0028] If the mid-span closure scheme is adopted, the cable force of the cross-section cable is relatively large near the cable section H9 during the suspension zone hoisting process. Before the hoisting of the mid-span suspension zone beam segment begins, the maximum cable force of H9 reaches 4624.6kN, which decreases sharply after the hoisting of the mid-span suspension zone beam segment. Therefore, it is necessary to determine the timing of tensioning the cross-section cable according to the cable force during construction, which requires high precision.

[0029] If the cross-section closure scheme is adopted, the stiffening beam in the cross-section will exhibit a larger local deformation error closer to the cable-stayed closure area. After closure, the relative rotation angle of the steel beam connection line will be large. Therefore, in order to ensure the smoothness of the alignment after welding, the cross-section needs to be adjusted to make the alignment of the steel beam in the cross-section smooth.

[0030] If the cantilever end closure scheme of the cable-stayed zone is adopted, the height difference at the closure point is 6.8m. After the forced connection, the relative angle of the copper beam in the intersection area is large at the temporary hinge connection point. To achieve smooth installation of the steel beams, it is necessary to adjust the alignment of the steel beams in the intersection area before welding. The main way to adjust the alignment is to change the length of the slings or use temporary slings, which is difficult and costly to construct.

[0031] In summary, due to the adoption of the above technical solutions, the beneficial effects of this invention are: the overall construction process of the cable-stayed suspension bridge has been optimized, and by using a cable-mounted crane, resources and construction time can be effectively saved. Attached Figure Description

[0032] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0033] Figure 1 This is a schematic diagram of step 1 of the present invention;

[0034] Figure 2 This is a schematic diagram of step 2 of the present invention;

[0035] Figure 3 This is a schematic diagram of step 3 of the present invention;

[0036] Figure 4 This is a schematic diagram of another state in step 3 of the present invention;

[0037] Figure 5 This is a schematic diagram of step 4 of the present invention;

[0038] Figure 6 This is a schematic diagram of step 5 of the present invention;

[0039] Figure 7 This is a schematic diagram of step 6 of the present invention;

[0040] Figure 8 This is a schematic diagram of step 7 of the present invention;

[0041] Figure 9 This is a graph showing the relationship between the number of stiffening beam pairs used in the hoisting of this invention and the distance of the cable saddle from the theoretical IP point;

[0042] Figure 10 This is a schematic diagram of the closure position of the intersection area in this invention;

[0043] Figure 11 This is a deformation diagram of the stiffening beam at the intersection closure zone of the present invention;

[0044] Figure 12 This is a schematic diagram of the closure position of the cantilever end in the cable-stayed section of the present invention;

[0045] Figure 13 This is a diagram showing the deformation state of the cantilever end of the cable-stayed section during closure in this invention.

[0046] Figure 14 This is an overall deformation diagram of the mid-span closure scheme 1 of the present invention;

[0047] Figure 15 This is an overall deformation diagram of the mid-span closure scheme 2 of the present invention;

[0048] Figure 16 This is an overall deformation diagram of the mid-span closure scheme 3 of the present invention;

[0049] Figure 17 This is a schematic diagram showing the logarithm of the hoisting beam segments and the height difference between the intersection zone and the suspension zone in this invention;

[0050] Figure 18 This is a diagram showing the force relationship between the stiffening beam in the mid-span suspension zone and the hinged steel beam in the intersection zone of this invention.

[0051] Figure 19 This is an axial force diagram of the joint between the steel beam in the suspension zone and the beam segment in the intersection zone of the present invention;

[0052] Figure 20 This is a diagram showing the cable force changes during the construction of the sling H9 of this invention;

[0053] Figure 21 This is a schematic diagram of the closure of the suspension section end of the present invention;

[0054] Figure 22 This is a diagram showing the overall deformation after the suspension cable closure segment of the present invention has been hoisted and the suspension cables in the intersection area have been tensioned.

[0055] Figure 23a This is a schematic diagram showing the deformation before the hinged connection at the closure joint;

[0056] Figure 23b This is a schematic diagram showing the deformation after the closure joint is connected.

[0057] Figure label:

[0058] 1-Main tower, 2-Auxiliary tower, 3-Mid-span main cable, 4-Side-span main cable, 5-Pull cable, 6-Mid-span main beam, 7-Side-span main beam. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of the embodiments of this application described and marked in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0060] In the description of the embodiments of this application, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship conventionally placed when the invention is used. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0061] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0062] Example 1

[0063] The overall construction sequence of a cable-stayed-suspension bridge system, such as... Figures 1-8 As shown, it includes the following steps:

[0064] Step 1: Construction of bridge towers and anchorages;

[0065] Step 2: Simultaneous construction of the cantilevered steel beams and main cables in the cable-stayed zone;

[0066] Step 3: Construction of stiffening girder hoisting in the suspension zone. After hoisting n stiffening girder segments in the main span, the side span and middle span girder segments are hoisted in a cross manner.

[0067] Step 4: Tensioning of the limiting slings;

[0068] Step 5: Hoist the main beam in the intersection area and set up temporary ties for sling tensioning;

[0069] Step 6: Hoisting of the closure section;

[0070] Step 7: Welding of steel beams in the suspension zone and second-phase construction.

[0071] In this embodiment, two bridge towers are provided. The construction of the bridge towers and anchorages is carried out first, following the same procedures as existing bridge construction. For the construction of the cable-stayed section and main cable, synchronous or asynchronous construction can be adopted. Asynchronous construction can involve erecting the main cable first, followed by the main beam of the cable-stayed section, or vice versa. Obviously, synchronous construction will save time, and this invention adopts synchronous construction. As the beam segment is hoisted, the pressure on the saddle increases, and the friction and jacking force also increase accordingly. In the empty cable state, the saddle of the cable saddle deflects and flares towards the side span. During the beam segment erection stage... The earlier the jacking and repositioning of the main span segments are carried out, the better. Therefore, in this invention, the main span stiffening girder is hoisted first, so that the saddle is jacked towards the main span to release the longitudinal shear force transmitted from the saddle to the bridge tower. This shear force is generated due to the imbalance of cable forces between the main cable in the middle span and the main cable in the side span. Therefore, by carrying out cross-hoisting of the girder segments in the side span and the middle span, the stiffening girder segments hoisted in the main span can be balanced. For the suspension area of ​​the side span, it can be hoisted from the anchorage side to the bridge tower side, or it can be installed from the bridge tower side to the anchorage side. There is not much difference between the two methods, only the jacking amount of the saddle is determined differently. In actual implementation, it can be selected according to the site conditions.

[0072] In step 3, n is 24, such as... Figure 9 As shown in the diagram, the relationship between the number of stiffening girder pairs being hoisted and the distance of the cable saddle from the theoretical IP point is as follows: It can be seen that when the 12th pair of stiffening girder segments are hoisted, the main cable saddle is close to the theoretical IP point. Without considering tower deflection, the cable saddle automatically returns to the center of the tower and locks, completing the early reset of the cable saddle. In the later stages, the focus is on controlling the tower deflection, and no further cable saddle jacking construction is required. This reduces the risk of cable saddle jacking construction caused by increased pressure from the upper structure in the later stages, and also reduces the need for temporary equipment.

[0073] Step 3 specifically includes the following steps:

[0074] Step 3.1: The stiffening girders in the suspension zone are hoisted using a cable-stayed crane, with the main span's 24 stiffening girder sections being hoisted first;

[0075] Step 3.2: After the 24 main span stiffening beams are hoisted, a side span beam segment is hoisted first, followed by a middle span beam segment. The alternating hoisting of side span beam segments and middle span beam segments is repeated until the non-closure segment of the suspension zone stiffening beam is hoisted.

[0076] In this embodiment, the installation of the stiffening beam in the suspension zone can adopt a hoisting method that combines multiple segments into a large segment, so as to significantly save the main line construction period. The cable-mounted crane can be planned to have the hoisting capacity of multiple segments into a large segment.

[0077] In step 4, the tensioning direction of the limiting cable is from the bridge tower towards the anchor span.

[0078] Step 5 specifically includes the following steps:

[0079] Step 5.1: Use a cable-mounted crane to hoist the main beam in the intersection area;

[0080] Step 5.2: Set temporary slings on the rear connecting beam of the section to be lifted, and advance by cyclically tensioning multiple pairs of temporary slings. During the lifting of the steel beam, gradually install permanent slings in the intersection area.

[0081] In this embodiment, the main girder in the cross section can currently be installed using a bridge deck crane or a cable-stayed crane. When a bridge deck crane is used to install the main girder in the cross section, it can be considered an extension of the main girder in the cable-stayed section, and the same installation method is used as for the cable-stayed section, so that the bridge deck crane can be removed in advance. Therefore, the installation of the main girder in the cross section using this method occurs before the installation of the stiffening girder in the suspension section. However, in this invention, the main girder in the cross section is longer and heavier, forcing the use of a bridge deck crane with higher performance, which leads to construction... Increased investment is required. If a cable-mounted crane is used for installation, given the large span of the suspension zone of this bridge, reaching the kilometer level, if the main beam of the cross zone is hoisted before the stiffening girder of the suspension zone is installed, the suspension zone will not have formed gravity stiffness. Under the influence of wind load and temperature, the static and dynamic displacement of the stiffening girder of the suspension zone will be large, which will increase the burden on the long cantilever of the main beam of the cable-stayed zone. At the same time, some temporary slings pulled on the main cable may collide with the cable stays. Therefore, if a cable-mounted crane is used to hoist the main beam of the cross zone, it must be done after the stiffening girder of the suspension zone is installed.

[0082] The closure in step 6 adopts one of the following schemes: mid-span closure, suspension zone end closure, intersection zone closure, or cable-stayed zone cantilever end closure.

[0083] Example 2

[0084] The difference between this embodiment and embodiment 1 is that the closure segment in step 6 is located at the end of the suspension zone.

[0085] In this embodiment, the suspension section is closed at the end, and the stiffening girder is hoisted from the mid-span to the bridge tower. The height difference at the closure joint is 0.1m and the path difference is 0.02m under the longitudinal unconstrained conditions at the design temperature. The closure joint is hinged, and the vertical shear force at the hinge point is 254.5kN. The interference between the cable-stayed and suspension systems is small, and the error identification is easy. The closure joint is connected after the tensioning is completed and the cross section is hoisted. Therefore, the closure section is located at the end of the suspension section.

[0086] If the intersection closure scheme is adopted, such as Figure 10 As shown, the closure segments are numbered 1-9 sequentially from the bridge tower towards the mid-span. The closure status of each segment (1-9) is checked after closure. The weld alignment of the stiffening beam is examined to ensure smoothness when closure is performed using the intersecting beam segments. Figure 11As shown, the closer to the cable-stayed section during closure, the larger the local deformation error of the stiffening girder in the intersection area. After closure, the relative rotation angle of the steel beam alignment is large. To ensure a smooth alignment after welding, the suspenders in the intersection area need to be adjusted to achieve tangential installation of the steel beam in the intersection area. Compared to closure in the suspension section, closure in the intersection area requires adjusting the length of the suspenders in the intersection area or using temporary suspenders to adjust the steel beam alignment, resulting in higher construction costs.

[0087] If a cantilever end closure scheme is adopted in the cable-stayed section, such as Figure 12 , Figure 13 As shown, the closure section has a height difference of 6.8m. After the forced connection, the relative angle of the copper beams in the intersection area at the temporary hinged connection point is large. To achieve a smooth connection and installation of the steel beams, it is necessary to adjust the alignment of the steel beams in the intersection area before welding. The main way to adjust the alignment is to change the length of the slings or use temporary slings, which is difficult and costly. Figure 12 In this context, NMC represents a cable and NMH represents a sling.

[0088] If the mid-span closure scheme is adopted, the stiffening girder is generally hoisted from the bridge tower towards the mid-span. Due to the construction issues in the intersection area, the mid-span closure can be divided into three schemes:

[0089] Option 1: The beam segment in the intersection area is constructed using a cable-stayed crane, with simultaneous tensioning of the suspenders and stay cables;

[0090] Option 2: The beam segments in the intersection area will be constructed using a bridge deck crane, and only the stay cables will be tensioned;

[0091] Option 3: The beam segments in the intersection area are constructed using a cable-stayed crane, with only the slings being tensioned.

[0092] In Option 2, such as Figure 15 As shown, since the cables in the cross section are not tensioned, the cross section and the suspension section cannot be connected. After the suspension section is closed at the mid-span, it is necessary to return to deal with the closure problem in the cross section, and finally return to the closure in the cross section, which increases the closure point and the difficulty of closure. Therefore, the solution is not advisable.

[0093] In Option 3, such as Figure 16 As shown, since the cables in the cross section are not tensioned, the cross section and the suspension section cannot be connected. Furthermore, the steel beams in the cross section are not welded, and the welded lines of the steel beams are not smooth. The length of the suspenders needs to be adjusted before the steel beams in the cross section can be welded. The construction measures are complicated, and there is also the problem of having to deal with both the mid-span closure joint and the cross section closure joint. Therefore, the solution is not advisable.

[0094] In Option 1, such as Figure 14 As shown, when both the stay cables and suspenders of the steel beams in the intersection area are installed, the height difference between the intersection area and the suspension area is not significant. The cables can be hoisted in sequence without addressing the closure issue, which is a relatively reasonable solution. However, the stress on the suspenders in the intersection area and the stress on the temporary connection between the steel beams in the intersection area and the suspension area need to be considered.

[0095] In Scheme 1, the beam segment in the intersection area is constructed using a cable-stayed crane, which simultaneously tensions the suspenders and stay cables. During the hoisting process from the bridge tower to the mid-span, the height difference between the joints of the beams in the intersection area and the suspended area is as follows: Figure 17 As shown, the initial height difference in the pure suspension zone was relatively large, with a maximum of 0.755m. It gradually decreased during the later construction process, and the height difference was close to 0 when the side and middle spans were hoisted together.

[0096] Secondly, in Scheme 1, a temporary hinged connection is made between the stiffening beam in the pure suspension zone at the initial hoisting stage and the steel beam in the intersection zone. The corresponding hinged point is subjected to the following forces: Figure 18 As shown, if a forced temporary connection is made with the cross section beam during the initial hoisting of the suspension zone steel beam, the connection force is relatively large, with a maximum connection force of 5265kN. As the steel beam is gradually hoisted towards the mid-span, the temporary connection force gradually decreases. After the side span steel beam is hoisted, the temporary connection force is the minimum of 1107kN. The appropriate connection timing can be selected according to the site conditions during the hoisting process.

[0097] Secondly, the axial force at the connection point between the steel beams in the suspension zone and the beam segments in the intersection zone during the hoisting process is as follows: Figure 19 As shown, with the increase of hoisting segments, the axial force increases. Before the mid-span closure of the steel beam in the suspension zone, the maximum axial force at the joint between the steel beam in the suspension zone and the cross beam segment is 2622kN. The axial force at the joint should also be considered during the construction process.

[0098] Furthermore, the changes in cable tension in the crossing area during the suspension hoisting process are shown in Tables 1 and 2 below. Figure 20 As shown, during the hoisting process in the suspension zone, the cable force of the cross-section cable is relatively large near the suspension zone cable H9. Before the hoisting of the mid-span suspension zone beam segment begins, the maximum cable force of H9 reaches 4624.6kN, which decreases sharply after the mid-span suspension zone beam segment is hoisted. Therefore, it is necessary to determine the timing of tensioning the cross-section cable according to the cable force condition during construction, which requires high precision.

[0099]

[0100]

[0101] In this embodiment, as Figure 21 As shown, the suspension zone end closure involves hoisting the mid-span suspension zone stiffening girder from mid-span towards the bridge tower. A closure section is set at the junction of the intersection and suspension zone. During the suspension zone end closure, all stay cables in the intersection zone are already tensioned. Figure 22 , Figure 23a , Figure 23bAs shown, when the closure joint is not connected, the height difference between the closure joints is 0.1m and the mileage difference is 0.02m under the longitudinal unconstrained design temperature. The closure joint is hinged, and the vertical shear force at the hinge point is 254.5kN. The closure is carried out at the end of the suspension zone. The stiffening beam is hoisted from the mid-span to the bridge tower. The interference between the cable-stayed and suspension systems is small, and the error identification is easy. After the tensioning is completed, the cross-section is hoisted and then the closure joint is connected. After the closure, the stiffening beam has a relatively smooth line and there are no obvious angles or slope errors between the welded beam segments.

[0102] Therefore, in this embodiment, the closure point is selected at the end of the suspension zone, which makes the closure point easier to control, the closure line is smooth, and no major adjustments are needed. The cable-stayed section in the intersection area can be constructed in advance, saving construction time.

[0103] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A general construction procedure for a cable-stayed-suspension bridge system, characterized in that, Includes the following steps: Step 1: Construction of bridge towers and anchorages; Step 2: Simultaneous construction of the cantilevered steel beams and main cables in the cable-stayed zone; Step 3: Construction of stiffening girder hoisting in the suspension zone. After hoisting n stiffening girder segments in the main span, the side span and middle span girder segments are hoisted in a cross manner. Step 4: Tensioning of the side span limiting cables; Step 5: Hoist the main beam in the intersection area and set up temporary ties for sling tensioning; Step 6: Hoisting of the closure section; Step 7: Welding of steel beams in the suspension zone and second-phase construction.

2. The overall construction procedure for a cable-stayed-suspension bridge according to claim 1, characterized in that, In step 3, n is 24.

3. The overall construction procedure for a cable-stayed-suspension bridge according to claim 1, characterized in that: Step 3 specifically includes the following steps: Step 3.1: The stiffening girders in the suspension zone are hoisted using a cable-stayed crane, with the main span's 24 stiffening girder sections being hoisted first; Step 3.2: After the 24 main span stiffening beams are hoisted, a side span beam segment is hoisted first, followed by a middle span beam segment. The alternating hoisting of side span beam segments and middle span beam segments is repeated until the non-closure segment of the suspension zone stiffening beam is hoisted.

4. The overall construction procedure for a cable-stayed-suspension bridge according to claim 1, characterized in that: In step 4, the tensioning direction of the limiting suspender cable is from the bridge tower toward the anchor span.

5. The overall construction procedure for a cable-stayed-suspension bridge according to claim 1, characterized in that: Step 5 specifically includes the following steps: Step 5.1: Use a cable-mounted crane to hoist the main beam in the intersection area; Step 5.2: Set temporary slings on the rear connecting beam of the section to be lifted, and advance by cyclically tensioning multiple pairs of temporary slings. During the lifting of the steel beam, gradually install permanent slings in the intersection area.

6. The overall construction procedure for a cable-stayed-suspension bridge according to any one of claims 1-5, characterized in that: In step 6, the closure segment is located at the end of the suspension zone.

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