Cable-stayed steel box girder bridge main bridge hoisting construction process

Abstract

The present application relates to a kind of cable-stayed steel box girder bridge main bridge hoisting construction process, the main bridge of the cable-stayed bridge uses steel box girder structure, main bridge is sequentially supported by first abutment, main pier, auxiliary pier and second abutment from left to right in longitudinal direction, the cable-stayed bridge tower lower end is located on the main bridge above main pier, the cable-stayed bridge construction process includes trestle construction, main bridge construction, tower construction and cable construction process;Main bridge is assisted construction using temporary support group in the construction process, the overall layout of temporary support group is more scientific by fully combining the laying sequence of main bridge, the parameter of tower position, the composition structure and erection position of temporary support group;Tower needs to be gradually used in the construction process Back cable tensioning, finally only permanent back cable is installed, guarantee the safety in the process of tower construction;In addition, bridge deck arch rib support group needs to be additionally increased when tower top segment construction, guarantee the safety and stability of tower whole when tower top segment installation.

Description

Technical Field

[0001] This invention relates to a bridge construction process, and more particularly to a construction process for hoisting the main bridge of a cable-stayed steel box girder bridge with an irregularly shaped single cable tower. Background Technology

[0002] Bridges are an important component of transportation infrastructure, providing vital support for national economic and social development. China has been a major bridge-building nation since ancient times, and bridge construction has greatly promoted the development of China's transportation industry.

[0003] Cable-stayed bridges are a common bridge structure, widely used in bridge construction in China. They mainly consist of pylons, main beams, and stay cables. Pylons, as a crucial component of cable-stayed bridges, are commonly categorized transversely as single-column, A-shaped, and inverted Y-shaped pylons; longitudinally as column-type, portal-type, A-shaped, and inverted Y-shaped pylons. However, with societal development, pylon design must not only meet load-bearing requirements but also achieve aesthetic appeal.

[0004] In the construction of irregular single-tower cable-stayed bridges, the main bridge involves not only the main bridge steel box girder itself, but also the construction of the pylons on it. When the pylons are teardrop-shaped and have an inclined curved structure in the longitudinal direction, the traditional construction process is time-consuming and poses certain construction safety hazards due to the offset of the center of gravity. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a construction process for the hoisting of the main bridge of a cable-stayed steel box girder bridge, which can solve the problems of long construction period and safety hazards of the main bridge and its teardrop-shaped cable towers.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: a construction process for the main bridge hoisting of a cable-stayed steel box girder bridge, wherein the main bridge adopts a steel box girder structure, and the main bridge is supported longitudinally from left to right by a first abutment, a main pier, an auxiliary pier, and a second abutment. The lower end of the cable-stayed bridge tower is located on the main bridge above the main pier. The construction process of the cable-stayed bridge includes the construction of a trestle bridge, the main bridge, the tower, and the cable installation. Its innovation lies in that the main bridge construction includes the construction of a segmented support group for the river channel, a segmented support group for the arch foot steel beam, and a segmented support group for the riverbank; the tower construction includes the construction of a bridge deck arch rib support group. The specific construction process is as follows:

[0007] Construction sequence of the trestle bridge: After the construction of the main pier, auxiliary pier and the first and second abutments is completed, trestle bridges are set up on both sides of the main bridge of the cable-stayed bridge, and the trestle bridges are parallel to the main bridge.

[0008] Main bridge construction sequence:

[0009] First, the construction of the temporary support group for the main bridge is carried out. The temporary support group for the main bridge includes several river channel segment support groups set at intervals between the first abutment and the main pier, arch foot steel beam segment support groups set on the main pier, and several riverbank segment support groups set between the main pier and the second abutment. There are at least two riverbank segment support groups.

[0010] Then, the steel box girder of the main bridge is divided into several steel box girder segments in the longitudinal and transverse directions, and each steel box girder segment is then hoisted and placed on the temporary support structure formed by the first abutment, the second abutment, and the temporary support group.

[0011] The specific installation sequence of the steel box girder segments is as follows: First, install one set of steel box girder segments between the first abutment and the nearest river channel segment support group; then install the steel box girder segments between adjacent river channel segment support groups; then install the steel box girder segments between the main pier and the adjacent river channel segment support group, and the steel box girder segments between the main pier and the adjacent riverbank segment support group; then install one set of steel box girder segments between the second abutment and the nearest riverbank segment support group; finally, install the steel box girder segments between adjacent riverbank segment support groups.

[0012] Cable tower construction procedures:

[0013] First, the construction of the bridge deck arch rib support group is carried out. The bridge deck arch rib support group includes the first arch rib support and the second arch rib support, which are set at the mid-span of the main bridge deck and spaced apart along the longitudinal direction of the bridge.

[0014] Then, the tower is divided into several main tower segments along the plumb line, specifically including a pair of paired tower bottom segments, at least two pairs of paired tower middle segments, and a common tower top segment.

[0015] The specific installation sequence of the main tower segments is as follows:

[0016] First, install a pair of tower base segments, then install the tower middle segments one by one on each of the two tower base segments. After each pair of tower middle segments is installed, temporary back cables are installed, tensioned, and adjusted. The temporary back cables are connected between the top of the tower middle segment and the main bridge, and are located on the back side of the tower in the direction of inclination. H200 steel is used for transverse connection between the top pair of tower middle segments. Finally, install the tower top segment. After installation, remove the first arch rib support and the second arch rib support, then install and tension the permanent back cables, and remove the temporary back cables.

[0017] Cable-stayed bridge construction procedure: After the permanent back cables are debugged, the stay cables are installed and initial tensioning is carried out. After the temporary support groups of the main bridge and the arch rib support groups of the bridge deck are removed, the stay cables are finally tensioned to complete the structural installation.

[0018] Furthermore, the river channel segment support group includes first steel pipe piles, first connecting supports, first distribution beams, and first regulating pipes. There are multiple first steel pipe piles arranged in a rectangular array. First connecting supports are set between the upper parts of the first steel pipe piles. The first connecting supports include upper horizontal supports and lower horizontal supports that are parallel to each other, as well as diagonal supports that connect the middle of the lower horizontal supports and the end of the upper horizontal supports. The first distribution beam is set at the top of the first steel pipe piles and connects each first steel pipe pile. Several vertically set first regulating pipes are set between the steel beam box of the main bridge and the first distribution beam.

[0019] The arch foot steel beam segmental support group includes a second steel pipe pile, a second distribution beam, and a second adjusting pipe. A pair of vertically arranged second steel pipe piles are distributed on the pier abutment along the transverse direction of the main bridge. A horizontal second distribution beam is set at the top of the two second steel pipe piles. Several second adjusting pipes are set between the steel beam box of the main bridge and the corresponding second distribution beam.

[0020] The riverbank segmental support group includes a third steel pipe pile, a third distribution beam, a third regulating pipe, and a third connecting support. There are multiple third steel pipe piles arranged in a rectangular array. A third connecting support is set between the upper parts of each third steel pipe pile. A horizontal third distribution beam is set between the tops of each third steel pipe pile. Several third regulating pipes for supporting the main bridge are connected to the upper end of the third distribution beam.

[0021] The bridge deck arch rib support structure has a first arch rib support and a second arch rib support. The first arch rib support and the second arch rib support have the same structure and are both vertically arranged. The first arch rib support and the second arch rib support are horizontally arranged and fixedly connected by several Z-shaped channel steels. Each includes a support base, a support frame, and a support top. The support base, support frame, and support top are arranged from bottom to top. The support base and support top both adopt a grid structure. The support base is set on the bridge deck of the main bridge, directly below the top segment of the tower. The support frame is a stacked rectangular frame structure, and the sides of the support frame are provided with several Z-shaped reinforcing steels.

[0022] Furthermore, the cable construction process specifically includes:

[0023] S3.1: Cable hoisting sequence: including temporary facility erection → cable deployment → cable hanging → tensioning → cable adjustment → cable protection;

[0024] S3.2: Preparatory work for cable hoisting: Preparation of temporary facilities for staff and workers' dormitories, offices, warehouses, kitchens and bathrooms, and water and electricity facilities; preparation of appropriate inner bushings and tension rods according to the cable specifications determined by the design and construction units, and selection of suitable tensioning equipment and hoisting equipment; requiring the cable manufacturer to transport the cables to the site in batches according to the usage plan, and checking the specifications and integrity of the cables upon arrival at the site; preparation of tensioning equipment, lifting equipment, and cable laying equipment;

[0025] S3.3: Construction of the stay cables:

[0026] Cable-stayed bridge cable hoisting and loading: After the cable-stayed bridge cable is transported to the bridge deck, it is loaded onto the cable tray using the existing crane on the bridge deck; the cable-stayed bridge cable must be placed in the center, and sleepers are added on the cable tray to prevent damage to the PE;

[0027] Tower end cable deployment: First, lift the anchor head with a truck crane, and at the same time rotate the cable laying machine to loosen the stay cable. After lifting the tower end anchor head to a certain height, slowly lower the hook to place the tower end anchor head and cable body on the anchor head trolley to meet the lifting range of the truck crane lifting system.

[0028] Tower end installation: The truck crane slowly lifts the cable stays, while the winch inside the tower slowly tightens the wire rope to lift the anchor head upwards;

[0029] Tower end traction: Continue to traction the stay cable to the pre-embedded pipe at the tower end, and adjust the angle of the anchor head entering the hole by coordinating the winch inside the tower and the hoisting winch at the top of the tower to ensure that the tower end anchor head enters the hole smoothly.

[0030] Cable deployment on the bridge deck: After the tower end is installed, there are still some stay cables in the cable reel. In order to fully deploy the stay cables, the cable reel is pulled and rotated by the bridge deck winch to fully deploy the stay cables in the cable reel. During the deployment process, a cable release trolley is placed under the stay cable body to prevent the cable body from directly contacting the ground.

[0031] Beam end traction: After the stay cables are fully extended, the clamp installation position is set according to the length of the pre-embedded pipe at the beam end. The lower anchor head is pulled towards the pre-embedded pipe opening by the beam surface traction winch. The closer the cable body is to the lower anchor point of the stay cable, the greater the traction force. During the traction process, the angle is adjusted with the help of a truck crane so that the anchor head can be smoothly put into the hole.

[0032] Beam end tensioning: After the traction is in place, remove the traction tools, install the tensioning support feet and jacks in sequence, connect the anchor head and tensioning rod with the connecting sleeve, and tighten the tie rod nut.

[0033] Furthermore, trial lifting is required before the main bridge construction and cable tower construction: Trial lifting preparation: lifting points are set up, auxiliary facilities are prepared, and all temporary supports are installed; the crane undergoes a comprehensive inspection to ensure it is in optimal condition and free from malfunctions during lifting; the integrity of the lifting tools, wire ropes, shackles, and hoists is checked; 100% integrity is ensured, otherwise replacements are made; the pier top elevation and support center deviation are re-measured, and a comprehensive inspection is conducted based on the measurement report provided by the project re-measurement; lifting can only proceed after the requirements are met; the stability of the temporary supports must be checked after they are set up. The quality of the structural components and the accuracy of the positioning must be verified; otherwise, adjustments must be made. Additionally, a comprehensive measurement and inspection must be conducted to ensure the correct elevation of the positioning blocks on the temporary support and the proper functioning of the safety facilities. Once confirmed, the beam segment can be hoisted. After the crane is in position, extend the crane boom to its maximum radius and lift the steel component 30-50cm slowly, carefully observing the crane's stability to prevent accidents. Once the crane is stable after lifting, the trial lift is complete. During the trial lift, a professional must be present to direct the operation, with on-site safety personnel and technical staff providing guidance and supervision throughout.

[0034] The advantages of this invention are as follows: In the construction of a non-standard single-tower double-cable-stayed bridge, the construction is carried out in the following order: trestle bridge construction, main bridge construction, tower construction, and cable installation. During the main bridge construction, temporary support groups are used for auxiliary construction. The composition and erection location of these temporary support groups fully integrate the two main factors of the main bridge's laying sequence and the tower's location, making the overall layout of the temporary support groups more scientific. In the tower construction process, because the tower structure is an inclined curved structure, the tower needs to be tensioned with back cables at each stage before finally installing permanent back cables, ensuring safety during tower construction. Furthermore, additional bridge deck arch rib support groups are needed during the construction of the tower's top segment to ensure the overall safety and stability of the tower during installation at the top segment. Attached Figure Description

[0035] Figure 1 This is an elevation layout diagram of a single-tower, double-cable-stayed bridge according to an embodiment of the present invention.

[0036] Figure 2 This is a plan view of a single-tower, double-cable-stayed bridge according to an embodiment of the present invention.

[0037] Figure 3 This is a plan view of the main bridge segment in an embodiment of the present invention.

[0038] Figure 4 This is a cross-sectional view of the main bridge segment in an embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the cable tower structure according to an embodiment of the present invention.

[0040] Figure 6This is a side view of a cable tower segment according to an embodiment of the present invention.

[0041] Figure 7 This is a frontal schematic diagram of a cable tower segment according to an embodiment of the present invention.

[0042] Figure 8 This is a front view of the river channel segment support group, arch foot steel beam segment support, riverbank segment support, and bridge deck arch rib support group in an embodiment of the present invention.

[0043] Figure 9 This is a plan view of the river channel segment support group, arch foot steel beam segment support, riverbank segment support, and bridge deck arch rib support group in an embodiment of the present invention.

[0044] Figure 10 This is a cross-sectional view of the river channel segment support assembly in the implementation of the present invention.

[0045] Figure 11 This is a cross-sectional view of the segmented support assembly of the arch foot steel beam in an embodiment of the present invention.

[0046] Figure 12 and Figure 13 The figures show a plan view and a side view of the bridge deck arch rib support assembly in an embodiment of the present invention.

[0047] Figure 14 This is a structural diagram of the two support bases of the bridge deck arch rib support assembly in an embodiment of the present invention.

[0048] Figure 15 This is a structural diagram of the two support top seats of the bridge deck arch rib support group in an embodiment of the present invention. Detailed Implementation

[0049] The present invention discloses a construction process for the main bridge hoisting of a cable-stayed steel box girder bridge. The main bridge adopts a steel box girder structure, and the main bridge is supported longitudinally from left to right by a first abutment, a main pier, an auxiliary pier, and a second abutment. The lower end of the cable-stayed bridge's pylon is located on the main bridge above the main pier. The construction process includes the following steps: trestle bridge construction, main bridge construction, pylon construction, and cable installation. In this invention, the main bridge construction includes the construction of river channel segmented support groups, arch foot steel beam segmented support groups, and riverbank segmented support groups. The pylon construction includes the construction of bridge deck arch rib support groups. The specific construction process is as follows:

[0050] Construction sequence of the trestle bridge: After the construction of the main pier, auxiliary pier and the first and second abutments is completed, trestle bridges are set up on both sides of the main bridge of the cable-stayed bridge, and the trestle bridges are parallel to the main bridge.

[0051] Main bridge construction sequence:

[0052] First, the construction of the temporary support group for the main bridge is carried out. The temporary support group for the main bridge includes several river channel segment support groups set at intervals between the first abutment and the main pier, arch foot steel beam segment support groups set on the main pier, and several riverbank segment support groups set between the main pier and the second abutment. There are at least two riverbank segment support groups.

[0053] Then, the steel box girder of the main bridge is divided into several steel box girder segments in the longitudinal and transverse directions, and each steel box girder segment is then hoisted and placed on the temporary support structure formed by the first abutment, the second abutment, and the temporary support group.

[0054] The specific installation sequence of the steel box girder segments is as follows: First, install one set of steel box girder segments between the first abutment and the nearest river channel segment support group; then install the steel box girder segments between adjacent river channel segment support groups; then install the steel box girder segments between the main pier and the adjacent river channel segment support group, and the steel box girder segments between the main pier and the adjacent riverbank segment support group; then install one set of steel box girder segments between the second abutment and the nearest riverbank segment support group; finally, install the steel box girder segments between adjacent riverbank segment support groups.

[0055] Cable tower construction procedures:

[0056] First, the construction of the bridge deck arch rib support group is carried out. The bridge deck arch rib support group includes the first arch rib support and the second arch rib support, which are set at the mid-span of the main bridge deck and spaced apart along the longitudinal direction of the bridge.

[0057] Then, the tower is divided into several main tower segments along the plumb line, specifically including a pair of paired tower bottom segments, at least two pairs of paired tower middle segments, and a common tower top segment.

[0058] The specific installation sequence of the main tower segments is as follows:

[0059] First, install a pair of tower base segments, then install the tower middle segments one by one on each of the two tower base segments. After each pair of tower middle segments is installed, temporary back cables are installed, tensioned, and adjusted. The temporary back cables are connected between the top of the tower middle segment and the main bridge, and are located on the back side of the tower in the direction of inclination. H200 steel is used for transverse connection between the top pair of tower middle segments. Finally, install the tower top segment. After installation, remove the first arch rib support and the second arch rib support, then install and tension the permanent back cables, and remove the temporary back cables.

[0060] Cable-stayed bridge construction procedure: After the permanent back cables are debugged, the stay cables are installed and initial tensioning is carried out. After the temporary support groups of the main bridge and the arch rib support groups of the bridge deck are removed, the stay cables are finally tensioned to complete the structural installation.

[0061] Example

[0062] This embodiment takes the construction of the cable-stayed bridge across the Qili River on Zhennanhe Road in Jiangbei New Area as an example. Located in the central business district of Jiangbei New Area, it starts at the intersection of Zhennanhe Road and Huoyaozhou Road in the west, crosses the Qili River, and ends at the intersection of Tianyi Avenue and Binjiang Avenue in the east, with a total length of approximately 0.67 km. Figure 1 , 2 As shown, the cable-stayed bridge mainly consists of the main bridge and the towers. The main bridge uses a steel box girder, with a total length of 130m, a width of 36.0m, and a beam height of 2.5m at the centerline. The top slab uses orthotropic steel decking. The towers have an octagonal cross-section, arranged in a "V" shape laterally, with varying cross-sections from top to bottom. The cable stays are 32 precast LPES5-55 cables, the backstays are 4 stranded steel cables of 15.2-43 specification, and the temporary cables are 4 stranded steel cables of 15.2-12 specification. The substructure includes one main pier, one auxiliary pier, and two abutments (the first and second abutments), all with foundations constructed from bored piles.

[0063] The main girder of the main bridge is a single-box, six-cell steel box girder, 36m wide, with a span of 88+22+20m and a total length of 130m. The main girder is horizontal to the bottom slab in the transverse direction, with a 2% bidirectional transverse slope on the top slab. The girder height at the centerline is 2.5m, and the web remains vertical. The material used is Q345qD steel. The top slab of the steel box girder is equipped with U-shaped and L-shaped stiffeners. The U-shaped stiffeners are spaced 600mm apart, 280mm high, 300mm wide, and 8mm thick; the L-shaped stiffeners are spaced 350mm apart and 200mm high, composed of 190*10mm + 120*10mm plates. The bottom slab of the steel box girder is also equipped with U-shaped and L-shaped stiffeners. The U-shaped stiffeners are spaced 600mm apart, 200mm high, 300mm wide, and 6mm thick; the L-shaped stiffeners are spaced 350mm apart and 200mm high, composed of 190*10mm + 120*10mm plates. The steel box girder has a total of 7 webs, 2 of which are cable-stayed anchored webs arranged at a 72° angle to the horizontal, and the rest are vertically arranged. The webs are generally 14mm thick at beam sections, 16mm thick at the tower-beam connection ends, and 20mm thick at the back-cable anchored sections. Each web has 5 longitudinal stiffeners, measuring 180*16mm. The standard spacing of the transverse diaphragms is 2m, with a thickness of 14mm, and the diaphragms at the supports are thickened to 24mm. The transverse diaphragms are either solid-web or semi-open, with solid-web diaphragms at the cable and support locations, and both longitudinal and transverse stiffeners are provided on the diaphragms. Each side of the steel box girder has a 6m long cantilever arm, with a lower flange measuring 480*16mm.

[0064] In this embodiment, the main bridge structure is divided as follows: Figure 3 , 4 As shown, the main bridge steel box girder is divided into 9 segments laterally and 7 segments longitudinally (the box girder corresponding to the arch foot is further divided into 2 segments due to excessive weight), for a total of 65 steel box girder segments. The table below is a list of the main bridge segments in this embodiment:

[0065]

[0066]

[0067] As Figure 5 shown, the overall shape of the cable tower is a water droplet shape, and the total height above the bridge deck is 38.88 m. It is "human"-shaped in the transverse direction of the bridge with a spacing of 19.387 m, and is an inclined curve in the longitudinal direction of the bridge (see Figure 1 ). At the bottom of the tower, it is固结 with the main girder. The cross-section of the cable tower is a symmetric octagonal cross-section, which is divided into 5 cable tower segments T1 to T5 along the vertical direction. Among them, the steel girders of segments T2 to T5 are provided with middle vertical plates in the transverse direction of the octagonal cross-section. The longitudinal width of the main tower cross-section is 2 m to 4.4 m, the transverse width is 0.75 m to 3.0 m, and the thickness of the wall plate and the middle vertical plate is 28 mm to 40 mm.

[0068] The tower end anchorage system of the cable tower adopts a steel anchor box, and the anchor is a cold cast anchor. The fixed end is on the tower and the tension end is on the beam. The steel plate directly welded to the stay cable anchor plate on the tower column adopts a Z-direction performance steel plate of grade Z35. The stay cable anchor plate is welded to the steel tower wall plate. The upper part of the anchor plate is provided with circular pin holes with a diameter of 150 - 180 mm and is stiffened with a circular steel plate, and the material is all Q345qD.

[0069] In this embodiment, the cross-section of the bridge tower arch rib is a symmetric octagonal cross-section, the tower height is 38.3 m, and the transverse spacing of the center line of the cable tower at the bridge deck is 19.387 m. Considering the structural form and hoisting working conditions comprehensively, as Figure 6 , 7 shown, the arch rib structure is divided into 7 segments, namely a pair of bottom tower segments T4-1 and T4-2 arranged in pairs, a pair of middle tower segments T3-1 and T3-2 arranged in pairs, a pair of middle tower segments T2-1 and T2-2 arranged in pairs, and a common top tower segment T1. The following table is the cable tower segment list of this embodiment:

[0070]

[0071]

[0072] After completing the construction of the main pier, auxiliary piers, and the first and second abutments, the trestle bridge construction is the first step. In this embodiment, the steel trestle bridge is a top-bearing truss bridge with a structure of 32 rows of single-layer Bailey trusses in the transverse direction. Reinforcing vertical members are added to the top of the Bailey bridge sections and load-bearing beam piles below the crawler crane tracks. The bridge deck uses a specially made bridge panel composed of 8mm thick checkered steel plates and I12.6 I-beams spaced 24cm apart. The transverse distribution beams are I22a, spaced 30cm apart. The longitudinal load-bearing beams are 3HN600×200 mm long (3m), and the transverse load-bearing beams are also 3HN600×200 mm long (15m). φ820×10mm steel pipe piles are used on the side closest to the piers, and φ710×10mm steel pipe piles are used on the other side. The main truss of the trestle bridge is assembled from 321-type standard steel trusses, with each Bailey section being 3m long and 1.5m high. The structural material is 16Mn, with each Bailey bridge beam weighing 270kg. There are 13 groups (32 rows) of Bailey bridges arranged transversely, with spacing of 95cm, 90cm, 45cm, and 22.5cm between groups. Within each group, the transverse spacing between the two rows of Bailey beams is also 90cm, 45cm, and 22.5cm. These are connected as a whole using 90-type and 45-type support frames. Vertical support frames are used at the ends of two adjacent truss beams, with one frame at each end. The support frames are connected to the truss beams using strut bolts and nuts. During connection, the hollow conical sleeves are inserted into the bolt holes of the support frame on the truss chord or end vertical member and secured with the support frame bolts. Their primary function is to ensure overall structural integrity. The Bailey beams are connected to the load-bearing beams using Bailey limit welding. The trestle bridge spans are arranged according to the standard 9m span.

[0073] During the construction of the main bridge, such as Figure 8 , 9 As shown, the temporary support group for the main bridge in this embodiment includes three spaced-apart river channel segment support groups ZC1, one arch foot steel beam segment support group ZC2, and three riverbank segment support groups ZC3. During the construction of the cable tower, the bridge deck arch rib support group ZC4 in this embodiment includes a first arch rib support and a second arch rib support. The first arch rib support and the second arch rib support are located at the mid-span of the main bridge deck and are spaced apart along the longitudinal direction of the bridge.

[0074] As a preferred structure in this embodiment: such as Figure 10 As shown, the river channel segment support group ZC1 includes several first steel pipe piles installed at intervals. Figure 10 The columns are marked as steel columns D630*10, with specifications of D630*8mm. There are 6 columns horizontally, spaced 6m apart, and 2 columns vertically, spaced 2m apart. A first connecting support is installed between the upper parts of each first steel pipe pile. The connecting support includes parallel upper and lower horizontal supports, as well as diagonal supports connecting the middle of the lower horizontal support and the end of the upper horizontal support. All of these are made of C14 double-channel steel. Figure 10The middle mark is designated as supporting double-span C14). The top of each first steel pipe pile is connected to a horizontally set first distribution beam, which is made of 40 double-span I-beams ( Figure 10 The middle mark is designated as double-span distribution beam (40). A first adjusting pipe is installed between the main bridge's steel box girder and the first distribution beam. The first adjusting pipe is made of D180*8mm steel pipe.

[0075] like Figure 11 As shown, the arch foot steel beam segmental support group ZC2 includes a pair of second steel pipe piles installed on the main pier abutment. The second steel pipe piles are D630*8 steel pipe piles. Figure 11 The middle section is marked as steel column D630*8), with a transverse spacing of 3.3m. A second distribution beam is installed at the top of each of the two second steel pipe piles. The second distribution beam uses 40 double-I-beams. Figure 11 The middle mark is designated as the second distribution beam (40). A second adjusting pipe is installed between the main bridge's steel box girder and the corresponding second distribution beam. The second adjusting pipe is made of D180*8mm steel pipe.

[0076] A steel plate with a specification of PL16*800*800mm is installed between the bottom end of the two steel pipe piles and the pile cap. The steel plate is connected to the pile cap with M16*160 expansion bolts, and the steel pipe piles are welded to the steel plate.

[0077] The ZC3 segmented support structure for the riverbank includes a third steel pipe pile, which is a D630*8 steel pipe pile, arranged in a horizontal spacing of 6m and a longitudinal spacing of 1.5m. A third connecting support is installed between the upper parts of each third steel pipe pile, providing horizontal support. A third distribution beam, with a double-jointed I40 specification, is installed at the upper end of the third steel pipe pile. The third regulating pipe is a D180*8 steel pipe. The bottom support consists of a 1.5*3.5m*1m enlarged foundation, on which 800*800 embedded parts are pre-installed, connecting to the lower end of the third steel pipe piles.

[0078] like Figure 12 and Figure 13 The bridge deck arch rib support group ZC4 includes a first arch rib support ZC4-1 and a second arch rib support ZC4-2. The first arch rib support ZC4-1 and the second arch rib support ZC4-2 are set at the mid-span of the main bridge deck and are spaced apart along the longitudinal direction of the bridge.

[0079] The first and second arch rib supports are basically the same in structure, but differ in height. The first arch rib support is higher than the second arch rib support. Both include a support base, a support frame, and a support top. The support base, support frame, and support top are arranged from bottom to top. Both the support base and support top adopt a grid structure. The support base is set on the bridge deck of the main bridge, directly below the top segment of the tower. The support frame is a stacked rectangular frame structure, and the sides of the support frame are provided with several Z-shaped reinforcing steel sections.

[0080] The ZC4 bridge deck arch rib support assembly uses standard sections of 1.5m, 3m, or 6m, employing single-piece assembly with an overall dimensions of 1.5m × 1.5m. It can be expanded to any combination using a 1.5m module. It consists of a support base (such as...) Figure 14 As shown), support frame and support top (as shown) Figure 15 The structure consists of three components (as shown), which can be freely combined and expanded as needed during construction. The support frame columns are made of D180*8 steel pipes, and the tie rod of component C is made of D89*5 steel pipes. The center dimensions of structure ZC4-1 are 1.5x3m, and the center dimensions of structure ZC4-2 are 1.5x3.6m. The first arch rib support ZC4-1 and the second arch rib support ZC4-2, as well as the first arch rib support ZC4-1 and the second arch rib support ZC4-2, are connected to the pylon using C14 channel steel to increase overall stability. The support base is connected to the outer perimeter of the bridge deck using clamps with a specification of PL10*200*300mm, with a clamp spacing of 0.5m. The top support is equipped with a D180*8 adjusting short pipe.

[0081] As a more specific implementation of this embodiment, the steel box girder segments of the main bridge are specifically installed as follows:

[0082] (1) A 350t crawler crane is stationed on one side of the trestle bridge. First, the steel box girder segments between the first abutment and the nearest river channel segment support group are installed from the mid-span to the cantilever end. Then, the steel box girder segments between adjacent river channel segment support groups are installed. That is, from the small mileage direction to the large mileage direction (P0#→P3#), the segments of the first, second, and third spans are installed sequentially from the mid-span to the cantilever end. The maximum lifting radius is 24m and the lifting weight is 44.3t. After the third cantilever segment on the north side is installed, the 350t crawler crane moves to the other side of the trestle bridge and installs the remaining segments of the first to third spans sequentially from the mid-span to the cantilever end from the small mileage direction to the large mileage direction (P0#→P3#). The maximum lifting radius is 21m and the lifting weight is 44.9t.

[0083] (2) Then, install the steel box girder segments between the main pier and the adjacent riverbank segment support group, and the steel box girder segments between the main pier and the adjacent riverbank segment support group. Then, install a set of steel box girder segments between the second abutment and the nearest riverbank segment support group. That is, after installing the third cantilever section on the south side, the 350t crawler crane continues from the small mileage direction to the large mileage direction (P0#→P3#), from the middle of the span to the cantilever end, to lift the segments of the fourth, fifth, and seventh spans, with a maximum lifting radius of 21m and a lifting weight of 48.7t. After installing the seventh cantilever section on the south side, the 350t crawler crane moves back to the temporary roadway on the north side and installs the remaining segments of the fourth, fifth, and seventh spans from the small mileage direction to the large mileage direction (P0#→P3#), with a maximum lifting radius of 23m and a lifting weight of 52t.

[0084] (3) Finally, install the steel box girder segments between the adjacent riverbank segment support groups; that is, after installing the 7th span cantilever segment on one side, the 350t crawler crane continues to stand on the temporary roadway on one side and installs the 6th span closure segment from the middle of the span towards the cantilever end, with a maximum lifting radius of 24m and a lifting weight of 14.3t. After installing the closure segment on the north side, the 350t crawler crane moves to the temporary roadway on the other side and installs the remaining closure segment from the middle of the span towards the cantilever end, with a maximum lifting radius of 21m and a lifting weight of 14.6t. The subsequent tower structure hoisting will only proceed after all segments have been welded and the welds have passed inspection.

[0085] The main tower segment is installed as follows:

[0086] First, a pair of tower base segments were installed: a 350t crawler crane was positioned on one side of the trestle to install tower base segment T4-1, with a lifting radius of 15m and a lifting weight of 48.6t. After installing tower base segment T4-1, the 350t crawler crane moved to the temporary driveway on the north side to install tower base segment T4-2, with a lifting radius of 15m and a lifting weight of 48.6t.

[0087] Next, the middle tower segments are installed sequentially on the two base segments. Temporary backstays are installed after each pair of middle tower segments is installed. Specifically, middle tower segments T3-1 and T3-2 are installed sequentially, with a lifting radius of 19m and a lifting weight of 46t. After middle tower segment T3-2 is installed, temporary backstays TS1 are installed and tensioned / tested simultaneously on both sides. After the temporary backstays TS1 are tested, middle tower segments T2-1 and T2-2 are installed using a 350t crawler crane, with a lifting radius of 22m and a lifting weight of 46t. After middle tower segment T2-2 is installed, H200 steel is used for lateral connection between the two middle tower segments to increase overall stability. Temporary backstays TS2 are installed and tensioned simultaneously on both sides.

[0088] Finally, the tower top segment is installed. After the temporary backstay TS2 is debugged, the tower top segment T1 is installed with a hoisting radius of 24m and a hoisting weight of 48t. After the tower top segment T1 is also installed and welded, the first arch rib support and the second arch rib support are removed, then the permanent backstay is installed and tensioned, and the temporary backstay is removed.

[0089] The cable-stayed bridge construction process of the present invention also includes the dismantling of the temporary support group of the main bridge: after the permanent back cable tensioning is completed, the temporary support group of the main bridge is dismantled.

[0090] In this embodiment, when dismantling the first, second, and third steel pipe piles in the temporary support group of the main bridge: due to the narrow space between the main bridge and the river surface, using a floating crane for pile extraction is risky and difficult. Therefore, this embodiment uses a winch for the extraction of the steel pipe piles. First, lifting lugs are welded to the bottom of the main bridge. The winch on the shore uses the lifting lugs and pulley system at the bottom of the main bridge to suspend a 90-type vibratory hammer for vibration, loosening the steel pipe piles. After the steel pipe piles are loosened, the vibratory hammer is removed, and the winch is started in conjunction with the pulley system to pull the steel pipe piles. When the upper end of the steel pipe pile is pulled to its highest point (at which point the upper end is lower than the lower surface of the main bridge), a floating box is used to cut off the steel pipe pile along the water surface. The above steps are repeated until all the steel pipe piles are pulled out.

Claims

1. A construction process for the main bridge hoisting of a cable-stayed steel box girder bridge, wherein the main bridge adopts a steel box girder structure, and the main bridge is supported longitudinally from left to right by a first abutment, a main pier, an auxiliary pier, and a second abutment. The lower end of the cable-stayed bridge's pylon is located on the main bridge above the main pier. The construction process includes the following steps: trestle bridge construction, main bridge construction, pylon construction, and cable installation; characterized in that: The main bridge construction includes the construction of segmented support assemblies for the river channel, segmented support assemblies for the arch foot steel beams, and segmented support assemblies for the riverbank. The pylon construction includes the construction of the bridge deck arch rib support assembly. The specific construction process is as follows: Construction sequence of the trestle bridge: After the construction of the main pier, auxiliary pier and the first and second abutments is completed, trestle bridges are set up on both sides of the main bridge of the cable-stayed bridge, and the trestle bridges are parallel to the main bridge. Main bridge construction sequence: First, the construction of the temporary support group for the main bridge is carried out. The temporary support group for the main bridge includes several river channel segment support groups set at intervals between the first abutment and the main pier, arch foot steel beam segment support groups set on the main pier, and several riverbank segment support groups set between the main pier and the second abutment. There are at least two riverbank segment support groups. Then, the steel box girder of the main bridge is divided into several steel box girder segments in the longitudinal and transverse directions, and each steel box girder segment is then hoisted and placed on the temporary support structure formed by the first abutment, the second abutment, and the temporary support group. The specific installation sequence of the steel box girder segments is as follows: First, install one set of steel box girder segments between the first abutment and the nearest river channel segment support group; then install the steel box girder segments between adjacent river channel segment support groups; then install the steel box girder segments between the main pier and the adjacent river channel segment support group, and the steel box girder segments between the main pier and the adjacent riverbank segment support group; then install one set of steel box girder segments between the second abutment and the nearest riverbank segment support group; finally, install the steel box girder segments between adjacent riverbank segment support groups. Cable tower construction procedures: First, the construction of the bridge deck arch rib support group is carried out. The bridge deck arch rib support group includes the first arch rib support and the second arch rib support, which are set at the mid-span of the main bridge deck and spaced apart along the longitudinal direction of the bridge. Then, the tower is divided into several main tower segments along the plumb line, specifically including a pair of paired tower bottom segments, at least two pairs of paired tower middle segments, and a common tower top segment. The specific installation sequence of the main tower segments is as follows: First, install a pair of tower base segments, then install the tower middle segments one by one on the two tower base segments. After each pair of tower middle segments is installed, temporary back cables are installed, tensioned, and adjusted. The temporary back cables are connected between the top of the tower middle segment and the main bridge, and are located on the back side of the tower in the direction of inclination. H200 steel is used for transverse connection between the top pair of tower middle segments. Finally, install the tower top segment. After installation, remove the first arch rib support and the second arch rib support, then install and tension the permanent back cables, and remove the temporary back cables. Cable-stayed bridge construction procedure: After the permanent back cables are debugged, the stay cables are installed and initial tensioning is carried out. After the temporary support groups of the main bridge and the arch rib support groups of the bridge deck are removed, the stay cables are finally tensioned to complete the structural installation.

2. The main bridge hoisting construction process of the cable-stayed steel box girder bridge according to claim 1, characterized in that: The river channel segment support group includes a first steel pipe pile, a first connecting support, a first distribution beam, and a first regulating pipe. There are multiple first steel pipe piles arranged in a rectangular array. A first connecting support is set between the upper parts of the first steel pipe piles. The first connecting support includes an upper horizontal support and a lower horizontal support that are parallel to each other, as well as an inclined support that connects the middle of the lower horizontal support and the end of the upper horizontal support. The first distribution beam is set at the top of the first steel pipe piles and connects each first steel pipe pile. Several vertically set first regulating pipes are set between the steel beam box of the main bridge and the first distribution beam. The arch foot steel beam segmental support group includes a second steel pipe pile, a second distribution beam, and a second adjusting pipe. A pair of vertically set second steel pipe piles are distributed on the pier abutment along the transverse direction of the main bridge. A horizontal second distribution beam is set at the top of the two second steel pipe piles. Several second adjusting pipes are set between the steel beam box of the main bridge and the corresponding second distribution beam. The riverbank segmental support group includes a third steel pipe pile, a third distribution beam, a third regulating pipe, and a third connecting support. There are multiple third steel pipe piles, which are distributed in a rectangular array. A third connecting support is set between the upper parts of each third steel pipe pile. A horizontal third distribution beam is set between the tops of each third steel pipe pile. Several third regulating pipes for supporting the main bridge are connected to the upper end of the third distribution beam. The bridge deck arch rib support structure has a first arch rib support and a second arch rib support. The first arch rib support and the second arch rib support have the same structure and are both vertically arranged. The first arch rib support and the second arch rib support are horizontally arranged and fixedly connected by several Z-shaped channel steels. Each includes a support base, a support frame, and a support top seat. The support base, support frame, and support top seat are arranged from bottom to top. The support base and support top seat both adopt a grid structure. The support base is set on the bridge deck of the main bridge, directly below the top segment of the tower. The support frame is a stacked rectangular frame structure, and the sides of the support frame are provided with several Z-shaped reinforcing steels.

3. The main bridge hoisting construction process of the cable-stayed steel box girder bridge according to claim 1, characterized in that: The specific procedures for cable construction are as follows: S3.1: Cable hoisting sequence: including temporary facility erection → cable deployment → cable hanging → tensioning → cable adjustment → cable protection; S3.2: Preparatory work for cable hoisting: Preparation of temporary facilities for staff and workers' dormitories, offices, warehouses, kitchens and bathrooms, and water and electricity facilities; preparation of appropriate inner bushings and tension rods according to the cable specifications determined by the design and construction units, and selection of suitable tensioning equipment and hoisting equipment; requiring the cable manufacturer to transport the cables to the site in batches according to the usage plan, and checking the specifications and integrity of the cables upon arrival at the site; preparation of tensioning equipment, lifting equipment, and cable laying equipment; S3.3: Construction of the stay cables: Cable-stayed bridge cable hoisting and loading: After the cable-stayed bridge cable is transported to the bridge deck, it is loaded onto the cable tray using the existing crane on the bridge deck; the cable-stayed bridge cable must be placed in the center, and sleepers are added on the cable tray to prevent damage to the PE; Tower end cable deployment: First, lift the anchor head with a truck crane, and at the same time rotate the cable laying machine to loosen the stay cable. After lifting the tower end anchor head to a certain height, slowly lower the hook to place the tower end anchor head and cable body on the anchor head trolley to meet the lifting range of the truck crane lifting system. Tower end installation: The truck crane slowly lifts the cable stays, while the winch inside the tower slowly tightens the wire rope to lift the anchor head upwards; Tower end traction: Continue to traction the stay cable to the pre-embedded pipe at the tower end, and adjust the angle of the anchor head entering the hole by coordinating the winch inside the tower and the hoisting winch at the top of the tower to ensure that the anchor head at the tower end enters the hole smoothly. Cable deployment on the bridge deck: After the tower end is installed, there are still some stay cables in the cable reel. In order to fully deploy the stay cables, the cable reel is pulled and rotated by the bridge deck winch to fully deploy the stay cables in the cable reel. During the deployment process, a cable release trolley is placed under the stay cable body to prevent the cable body from directly contacting the ground. Beam end traction: After the stay cables are fully extended, the clamp installation position is set according to the length of the pre-embedded pipe at the beam end. The lower anchor head is pulled towards the pre-embedded pipe opening by the beam surface traction winch. The closer the cable body is to the lower anchor point of the stay cable, the greater the traction force. During the traction process, the angle is adjusted with the help of a truck crane so that the anchor head can be smoothly put into the hole. Beam end tensioning: After the traction is in place, remove the traction tools, install the tensioning support feet and jacks in sequence, connect the anchor head and tensioning rod with the connecting sleeve, and tighten the tie rod nut.

4. The main bridge hoisting construction process of the cable-stayed steel box girder bridge according to claim 1, characterized in that: Before the construction of the main bridge and cable towers, a trial lift is required: Trial lift preparation includes: setting up lifting points, preparing auxiliary facilities, and installing all temporary supports; conducting a comprehensive inspection of the crane to ensure it is in optimal condition and free from malfunctions during lifting; checking the integrity of the lifting tools, wire ropes, shackles, and hoists; ensuring 100% integrity, otherwise replacing them; re-measuring the pier top elevation and support center deviation, and conducting a comprehensive inspection based on the measurement report provided by the project; lifting can only proceed after meeting the requirements; after the temporary supports are set up, their stability must be checked. Check whether the positioning is correct and whether it is in good condition. If not, adjustments must be made. In addition, conduct a comprehensive measurement and inspection to check whether the elevation of the positioning pads on the temporary support is correct and whether the safety facilities are in good condition. After confirming that everything is correct, the beam segment can be hoisted. After the crane is in position, extend the crane arm to the maximum radius and lift the steel component 30-50cm. Lift slowly and pay attention to the stability of the crane to prevent accidents. Once the crane is stable after lifting, the trial lifting is over. During the trial lifting, a professional person must be in charge, and the on-site safety officer and technical personnel must provide guidance and supervision throughout the process.

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