Tower crane elevator arrangement method and tower crane conversion mechanism for construction of main tower and main beam of cable-stayed bridge

Abstract

The application discloses a tower crane elevator arrangement method and a tower crane conversion mechanism for construction of a main tower and a main beam of a cable-stayed bridge, belongs to the technical field of bridge construction, and aims to solve the problems of space conflict of tower crane elevator arrangement of an ultra-wide main beam cable-stayed bridge, insufficient safety and stability caused by an overlong attachment system, and difficulty of traditional equipment in adapting to different construction stages. The arrangement method comprises the following steps: initially arranging a tower crane elevator for segmented main tower erection, arranging a bracket and an additional elevator for climbing form construction, converting the tower crane and capping the main tower, erecting a main beam by means of a pier-side support, connecting the main beam to a cable and closing the main beam, and the conversion mechanism comprises a support framework, a tower crane conversion connecting frame, an elevator conversion connecting frame and a leveling assembly. The application can avoid space conflict and safety risks, dynamically adapt to construction stages, has strong universality of the conversion mechanism, ensures equipment stability, reduces costs and improves efficiency.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction technology, specifically a method for arranging tower crane elevators and a conversion mechanism for the construction of the main tower and main beam of a cable-stayed bridge. Background Technology

[0002] As cable-stayed bridges in my country develop towards higher piers, longer spans, and heavier loads, their core structure construction relies on tower cranes (hereinafter referred to as tower cranes) for hoisting tasks and construction elevators (for transporting personnel and materials), and must comply with the "Design Specifications for Highway Cable-Stayed Bridges," "Technical Specifications for Highway Bridge and Culvert Construction," and relevant safety requirements for special equipment. Traditional tower crane elevator layout follows the principle of "foundation placement on the pier cap, avoiding the projection of the main beam," which is feasible in conventional cable-stayed bridges. However, due to upgraded traffic demands (such as eight-lane dual carriageways), cable-stayed bridges with ultra-wide main beams (width much larger than the lower pier cap) face numerous technical challenges. ① Due to the limited space of the foundation, the equipment tower or attachment system may easily intrude into the construction space of the main beam, interfering with the assembly of the hanging basket and the hoisting of the main beam segments, violating the standard that "temporary facilities shall not hinder the construction of the main structure", and posing risks of falling from height and equipment collision. ② If the equipment foundation is moved to the trestle bridge on the side of the bridge, the trestle bridge needs to be ten to tens of meters away from the pier, which will result in the equipment attachment system being too long, increasing its flexibility and deteriorating its stress, failing to meet the safety requirements of special equipment, and the unconventional attachment rods will greatly increase the cost. ③ The main tower adopts climbing formwork and is constructed in sections of "lower-middle-upper tower column". Traditional fixed equipment is difficult to adapt to the needs of different tower sections. Moreover, when the main tower is converted to the main beam, there is a lack of standardized equipment adjustment plan, which can easily delay the construction period and cause safety management loopholes.

[0003] In summary, the key challenges in the construction of ultra-wide main girder cable-stayed bridges are overcoming the dual bottlenecks of spatial conflict in equipment layout and balancing safety and economy, as well as solving the problem of dynamic and rational layout of tower cranes and elevators throughout their entire lifecycle. Summary of the Invention

[0004] In view of the problems of spatial conflict in the arrangement of tower cranes and elevators for ultra-wide main beam cable-stayed bridges and insufficient safety and stability caused by the excessive length of the attachment system, the present invention aims to provide a method and conversion mechanism for arranging tower cranes and elevators for the construction of main towers and main beams of cable-stayed bridges. Its core idea is to use the main tower structure as the carrier and the construction stage as the guide to realize the dynamic adaptation and arrangement of tower cranes and elevators throughout the entire life cycle.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On the one hand, a method for arranging tower crane elevators for the construction of the main tower and main girder of a cable-stayed bridge is proposed, including the following steps: S1. Installation of main tower sections and initial tower cranes and initial construction elevators; the initial tower cranes include tower crane #1 and tower crane #2; the initial construction elevator and tower crane #2 are directly installed on the foundation, while tower crane #1 is installed on the foundation through a tower crane conversion mechanism; S2. The main tower climbing formwork construction is synchronized with the initial tower crane and initial construction elevator; during the main tower climbing formwork construction process, bracket A is installed on the main tower, and elevator #2 is directly installed on bracket A, and elevator #3 is installed on bracket A through the tower crane conversion mechanism; S3, Tower Crane Conversion and Main Tower Capping; This includes: disassembling Elevator #3 from its corresponding tower crane conversion mechanism, disassembling Tower Crane #1 from its corresponding tower crane conversion mechanism, and using Tower Crane #2 to disassemble Tower Crane #1 and install it at the location corresponding to Elevator #3; S4. Pier-side scaffolding erection and initial construction of the main beam; S5. Main beam cable hanging and cantilever closure.

[0006] Furthermore, in step S4, the top height of the initial construction elevator is adjusted to be below the bottom surface of the main beam, and the No. 2 tower crane is dismantled by converting the tower crane.

[0007] Furthermore, the tower crane conversion mechanism includes: a support frame, the bottom of which is pre-embedded with bolts on the support platform or bracket A; a tower crane conversion connecting frame, which is sleeved on the outer periphery of the support frame and has a connecting plate one at the top that is adapted to connect with the bottom of the tower body of the No. 1 tower crane; and an elevator conversion connecting frame, which is sleeved inside the support frame and has a connecting plate two at the top that is adapted to connect with the bottom of the guide rail frame of the No. 3 elevator.

[0008] Furthermore, a leveling component is provided between the bottom of the support frame and the bottom of the tower crane conversion frame, and a level is also provided on the outer periphery of the tower crane conversion frame.

[0009] Furthermore, the leveling component includes: a fixed base, the bottom of which is detachably connected to the bottom of the support frame and has a through groove extending through the fixed base; a lifting platform, the bottom of which is inclined and one end is slidably disposed in the through groove of the fixed base, and the other end abuts against the bottom end face of the tower crane conversion connection frame; and a wedge block, the upper end face of which has a wedge-shaped surface structure adapted to the inclined surface and is slidably disposed in the through groove.

[0010] Furthermore, the leveling assembly also includes: a limiting block with a threaded through hole communicating with the through groove and detachably connected to the fixed base; and a movable rod threadedly connected to the threaded through hole, one end of which has a protrusion that is movably disposed in the cavity opened by the wedge block, and the other end passing through the threaded through hole.

[0011] On the other hand, a tower crane conversion mechanism for the construction of the main tower and main beam of a cable-stayed bridge is proposed, including the tower crane conversion mechanism used in the above method.

[0012] The beneficial effects of this invention are: 1. The arrangement method of the present invention utilizes the bracket A on the outer side of the first layer of the cross brace of the main tower column to expand the equipment installation space, and transfers the additional construction elevator and the converted tower crane to the outer area of ​​the main tower body. While avoiding the impact of arranging tower cranes, elevators and other attachment systems within the projection range of the ultra-wide main beam on its construction, it also avoids spatial interference between the tower crane body, elevator attachment system and key processes such as hanging basket assembly, bridge deck crane travel and main beam segment hoisting, effectively avoiding safety risks such as high-altitude falls and equipment collisions; 2. The arrangement method of this invention dynamically adjusts the position and number of tower cranes and elevators according to different stages of main tower construction, main tower capping, and main beam construction. During the main tower construction stage, climbing formwork drives the equipment to climb synchronously to meet the needs of segmented tower column construction. After the main tower is closed, the tower cranes are converted to form a modified tower crane adapted to the main beam construction, increasing the lifting coverage of the main beam segments. During the main beam construction stage, redundant equipment is removed to reduce space occupation. The entire process does not require additional equipment foundations and relies on existing equipment to complete the conversion, avoiding the delays and additional costs caused by equipment adjustments in traditional solutions. 3. The tower crane conversion connecting frame and elevator conversion connecting frame of the present invention are respectively sleeved on the outer periphery and the inner side of the support frame, forming a "one frame for dual use" adaptable structure. The connecting plate one at the top of the tower crane conversion connecting frame is precisely adapted to the tower crane body flange, and the connecting plate two at the top of the elevator conversion connecting frame is flexibly adapted to the elevator guide rail frame mounting plate, which can be compatible with different models of tower cranes and elevators; at the same time, it is compatible with two types of installation carriers, namely the support platform and the bracket A, without the need to design a conversion mechanism separately for different installation scenarios, which has strong versatility and reduces equipment adaptation costs; 4. The leveling component of the conversion mechanism of this invention adopts a mechanical transmission structure of movable rod-wedge block-lifting platform. With the help of the level on the outer periphery of the tower crane conversion connecting frame, the equipment level can be monitored and adjusted in real time. By turning the movable rod, the wedge block is pushed to slide. The inclined surface of the wedge block drives the lifting platform to move up and down for fine leveling. After leveling, the position of the movable rod is locked by the anti-loosening nut to avoid the failure of the leveling state due to vibration during construction, thus ensuring the installation accuracy and operational stability of the equipment. Attached Figure Description

[0013] Figure 1 This is a flowchart of the arrangement method of the present invention; Figure 2 This is a schematic diagram of the transverse segment division of the main tower of the present invention; Figure 3 This is a schematic diagram of the initial lateral arrangement of the tower crane and initial construction elevator of the present invention; Figure 4This is a schematic diagram of the initial tower crane and initial construction elevator layout of the present invention; Figure 5 This is a schematic diagram of the transverse bridge arrangement of the additional construction elevator and bracket A in this invention; Figure 6 This is a schematic diagram of the additional construction elevator layout for this invention; Figure 7 This is a schematic diagram of the transverse bridge layout of the elevator after the conversion according to the present invention; Figure 8 This is a floor plan of the elevator layout after the conversion according to the present invention; Figure 9 This is a schematic diagram of the transverse bridge section for the erection of the pier-side support and main beam of the present invention. Figure 10 This is a plan view of the demolition of tower crane #2 for this invention; Figure 11 This is a schematic diagram of the main beam closure and cable-stayed suspension along the bridge direction of the present invention; Figure 12 This is a schematic diagram of the tower crane conversion connecting frame-support skeleton assembly structure of the present invention; Figure 13 For the present invention Figure 12 Partial view at point N in the middle; Figure 14 This is a schematic diagram of the elevator transfer connection frame-support skeleton assembly structure of the present invention; Figure 15 For the present invention Figure 14 Partial view at point M in the middle; Figure 16 This is a schematic diagram of the supporting skeleton structure of the present invention; Figure 17 This is a schematic diagram of the tower crane conversion connection frame structure of the present invention; Figure 18 This is a schematic diagram of the elevator transfer connection frame structure of the present invention; Figure 19 This is a schematic diagram of the leveling component structure of the present invention; Figure 20 This is a cross-sectional view of the wedge block-moving rod of the leveling component of the present invention; Figure 21 This is a schematic diagram of the transition pad structure of the present invention.

[0014] in: 1. Support frame; 101. Reinforcing angle plate; 102. Reinforcing plate; 103. Transition pad; 104. Compensating pad one; 105. Reinforcing rib one; 106. Frame one; 2. Tower crane conversion connection frame; 201. Connecting plate one; 202. Level; 203. Reinforcing rib two; 204. Compensating pad two; 205. Frame two; 3. Elevator conversion connection frame; 301. Connecting plate two; 302. Reinforcing rib three; 303. Frame three; 4. Leveling assembly; 401. Fixed base; 402. Lifting platform; 403. Wedge block; 4 04. Limiting block; 405. Movable rod; 5. Main tower; 501. First segment of main tower; 6. Pier; 7. Initial tower crane; 701. Tower crane #1; 702. Tower crane #2; 8. Initial construction elevator; 9. Lower crossbeam support; 10. Main tower cross brace; 11. Bracket A; 12. Additional construction elevator; 1201. Elevator #2; 1202. Elevator #3; 13. Bracket C; 14. Tower crane after conversion; 15. Pier-side support; 16. Main beam; 17. Girder erecting crane; 18. Upper crossbeam bracket B; 19. Tower base; 20. Stay cable. Detailed Implementation

[0015] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0016] Example 1: This embodiment provides a method for arranging tower cranes for the construction of the main tower and main girder of a cable-stayed bridge, as shown in the attached diagram. Figures 1-11 The arrangement method specifically includes the following steps: S1. The main tower 5 is segmented and installed with the initial tower crane 7 and the initial construction elevator 8; the initial tower crane 7 includes tower crane #1 701 and tower crane #2 702; the initial construction elevator 8 and tower crane #2 702 are directly installed on the foundation 6, and tower crane #1 701 is installed on the foundation 6 through a tower crane conversion mechanism; S2. The climbing formwork construction of the main tower 5 is synchronized with the initial tower crane 7 and the initial construction elevator 8; during the climbing formwork construction of the main tower 5, bracket A11 is installed on the main tower 5, and elevator #2 120 is directly installed on bracket A11. 1. Install elevator #3 1202 on bracket A11 using the tower crane conversion mechanism; S3. Tower crane conversion and main tower 5 capping; including: disassembling elevator #3 1202 from the corresponding tower crane conversion mechanism, disassembling tower crane #1 701 from the corresponding tower crane conversion mechanism, disassembling tower crane #1 701 using tower crane #2 702, and installing it at the position corresponding to elevator #3 1202; S4. Erection of pier-side support 15 and initial construction of main beam 16; S5. Cable hanging and cantilever closure of main beam 16.

[0017] More specifically: Reference Figures 2-4The main tower is segmented into 5 sections and installed with the initial tower crane 7 and the initial construction elevator 8; the initial tower crane 7 includes tower crane #1 701 and tower crane #2 702; the initial construction elevator 8 and tower crane #2 702 are directly installed on the foundation 6, while tower crane #1 701 is installed on the foundation 6 via a tower crane conversion mechanism; specifically, the following sub-steps are included. S101: Based on the structural design characteristics of main tower 5 (segmented into lower, middle, and upper tower columns) and for ease of construction, main tower 5 is divided into several segments along the vertical direction, with adjacent segments maintaining the same height, as shown in the attached diagram. Figure 2 As shown, the main tower 5 is divided into 25 sections, which can be numbered sequentially from bottom to top as ①, ②, ③... This ensures that subsequent climbing formwork construction can proceed simultaneously. When dividing the structure into sections, the design locations of the cross braces and beams of main tower 5 must be avoided to prevent conflicts with subsequent structural construction.

[0018] S102: After the main tower is divided into sections 5, the foundation 6 is constructed and the tower crane conversion mechanism is pre-installed on the foundation 6. The foundation 6 adopts a large-volume concrete pouring process. First, the foundation pit of the foundation 6 is excavated, the foundation concrete is laid, the foundation reinforcement is tied, the formwork of the foundation 6 is installed, and the tower base 19 is poured on the foundation 6. Before pouring, the pre-embedded bolts for the tower crane conversion mechanism are pre-embedded on the foundation 6 and the tower base 19, and the upright connecting parts of the pier bracket 15 are pre-embedded on the top surface of the foundation 6. The upright connecting parts and the pre-embedded bolts need to be welded and fixed to the reinforcement of the foundation 6 and the tower base 19 to prevent displacement during pouring. The top of the pre-embedded bolts protrudes a certain length from the top surface of the tower base 19 for connecting the tower crane conversion mechanism. The tower crane conversion mechanism is used for the subsequent dismantling of tower crane 701 and its relocation to the position of the corresponding additional construction elevator 1201 (this step corresponds to sub-step S302). It should be noted that the tower base 19 of the main tower 5 is installed on the foundation 6, serving as the foundation of the entire main tower 5.

[0019] S103: Install the initial tower crane 7 and the initial construction elevator 8. After the concrete strength of the poured foundation 6 and tower base 19 reaches 80% of the design requirements, install the initial tower crane 7 on the foundation 6. The initial tower crane 7 includes tower crane #1 701 and tower crane #2 702, which are located on both sides of the main tower 5. Connect the bottom flange of tower crane #1 701 to the tower crane conversion mechanism, insert high-strength bolts, and tighten them. At the same time, install the initial construction elevator 8 on the top of the tower base 19 on the foundation 6, and install the bottom mounting plate of the guide rail frame of the initial construction elevator 8 on the tower base 19.

[0020] S104: Finally, tie the reinforcing bars of the first segment 501 of the main tower 5 to the top of the tower base 19, and install the main tower formwork.

[0021] Furthermore, refer to Figure 5 and Figure 6The main tower 5 climbing formwork construction is synchronized with the initial tower crane 7 and the initial construction elevator 8; during the main tower 5 climbing formwork construction process, bracket A11 is installed on the main tower 5, and elevator #2 1201 is directly installed on bracket A11, while elevator #3 1202 is installed on bracket A11 through the tower crane conversion mechanism; specifically including the following steps: S201: Before each ascent, clean the debris from the top surface of the main tower 5, tie the steel bars of the next segment, install the tower crane attachment frame connectors and elevator attachment frame connectors, adjust and fix the climbing formwork position; pour concrete, and after curing until the strength meets the standard, loosen the connection between the formwork and the climbing frame, start the hydraulic system to drive the climbing frame and formwork to the position of the previous segment, and repeat the above process.

[0022] S202: Connect tower crane #1 (701) and tower crane #2 (702) to the main tower 5 via tower body attachment frames. Install one attachment frame every 2-3 main tower segments. At the same time, the initial construction elevator 8 is connected to the main tower 5 via guide rail attachment frames, and the installation spacing of the attachment frames is adapted to the tower crane attachment frames.

[0023] S203: The lower crossbeam support 9 is erected using steel pipe scaffolding, with the bottom of the uprights resting on the tower base 19 or the foundation 6. A steel distribution beam is laid on top of the lower crossbeam support 9, and formwork (bamboo plywood or steel formwork) is laid on the distribution beam. The joints of the formwork are sealed to prevent grout leakage.

[0024] S204: Install the main tower cross brace 10, bracket A11, and additional construction elevator 12. When the main tower 5 is constructed to the designed position of the main tower cross brace 10 in the middle tower column, pre-install cross brace connectors on both sides of the main tower 5. Continue climbing the formwork to more than three segments above the main tower cross brace 10, then hoist the main tower cross brace 10 to the designed position. Bolt or weld the two ends of the main tower cross brace 10 to the tower body connectors to ensure that the main tower cross brace 10 and the main tower 5 form an integral load-bearing structure. Bracket A11 is a welded steel frame installed on the outer sides of the main tower 5 (corresponding to the height of the main tower cross brace 10). First, pre-embedded bolts for bracket A11 are pre-installed on the main tower 5 (pre-installed during the pouring of this segment). Hoist bracket A11 to the pre-embedded bolt position, adjust the levelness of bracket A11 (monitored by a level), and tighten bracket A11 to the pre-embedded bolts with high-strength bolts to ensure that the top surface of bracket A11 is flat and the load-bearing capacity meets the elevator installation requirements. Elevator #2 (1201) and elevator #3 (1202) are installed on brackets A11 on both sides, respectively. Elevator #2 (1201) is directly installed on bracket A11, and its installation process is the same as that of the initial construction elevator 8. A tower crane conversion mechanism is pre-installed on bracket A11 corresponding to elevator #3 (bolts for connecting the tower crane conversion mechanism are pre-embedded in bracket A11). The elevator guide rail of elevator #3 (1202) is connected to the tower crane conversion mechanism. The car, drive unit, and safety facilities are installed. The verticality of the guide rail is adjusted. Finally, a trial run is conducted to ensure normal elevator operation.

[0025] S205: Continue climbing formwork construction of main tower 5 to the designed position of the upper crossbeam, and erect the upper crossbeam bracket B18. The upper crossbeam bracket B18 is fixed to the tower body of main tower 5 by pre-embedded bolts. When main tower 5 is constructed to the designed position of the closure section, install the closure section bracket C13 (bracket C13 is a truss structure with a span suitable for the length of the closure section). The two ends of bracket C13 are fixed to the pre-embedded connectors on both sides of the tower body of main tower 5.

[0026] Furthermore, refer to Figure 7 and Figure 8 The tower crane conversion and main tower 5 capping process includes: disassembling elevator #3 1202 from its corresponding tower crane conversion mechanism, disassembling tower crane #1 701 from its corresponding tower crane conversion mechanism, and using tower crane #2 702 to disassemble tower crane #1 701 and install it at the corresponding position of elevator #3 1202; specifically, the following steps are included: S301: After the concrete strength of the main tower's fifth closure section reaches the design requirements, dismantle elevator #3 (1202). First, stop the operation of elevator #3 (1202), cut off the power, disconnect the car from the drive unit, and use a tower crane to lift the car to the ground; then dismantle the elevator guide rail frame in sections (from top to bottom, each section of the guide rail frame is lifted by a tower crane), and remove the guide rail frame attachment frame; finally, remove elevator #3 (1202) from the tower crane transfer mechanism.

[0027] S302: Use tower crane #2 (702) to dismantle tower crane #1 (701). First, remove the boom and counterweight boom of tower crane #1 (701). Then, dismantle the tower body of tower crane #1 (701) in sections (each section is hoisted to the ground and temporarily stored using tower crane #2 (702)). Next, use tower crane #2 (702) to hoist the dismantled tower body sections of tower crane #1 (701) to bracket A11 where elevator #3 (1202) was originally located. Connect tower crane #1 (701) to the tower crane conversion mechanism on bracket A11, converting tower crane #1 (701) into tower crane #14 (14).

[0028] S303: After the conversion of tower crane 14 is completed, the climbing formwork process will continue to be used to construct the remaining segments of the main tower 5 (until the capping segment). The construction process is the same as that of the main tower segments mentioned above. During this period, tower crane 702, tower crane 14, and elevator 1201 will climb synchronously (the tower crane will extend the tower body through the jacking system, and the elevator will extend the guide rail frame through the jacking device) to ensure that the height of tower crane 702, tower crane 14, and elevator 1201 is always higher than the current construction segment of the main tower 5 to meet the needs of hoisting and personnel transportation.

[0029] Furthermore, refer to Figure 9 and 10 Step S4, the erection of the pier-side support and the initial construction of the main beam 16, specifically includes the following steps: S401: Use steel pipe scaffolding or steel frame to erect the pier-side support 15. The bottom of the uprights is bolted to the pre-embedded connectors of the foundation 6. The spacing between the uprights and the step distance of the horizontal bars are determined according to the construction load calculation of the main beam 16.

[0030] S402: Remove the upper guide rail frame of the initial construction elevator 8 (remove from top to bottom) to lower the car of the initial construction elevator 8 below the bottom surface of the main beam 16. Retain the lower guide rail frame and car of the initial construction elevator 8 for subsequent personnel transportation. After adjustment, start the initial construction elevator 8 for trial operation to ensure that the car can move up and down normally. Use the converted tower crane 14 to assist in the dismantling of tower crane 702 #2. First, dismantle the boom and counterweight boom of tower crane 702 #2, then dismantle the tower body of tower crane 702 #2 in sections (dismantle from top to bottom, each section of the tower body is lifted to the ground by the converted tower crane 14). Clean up debris on the top surface of the foundation 6 and the tower base 19.

[0031] S403: The main beam 16 is erected on the platform of the support 15 on the top of the pier and beside the pier. In this embodiment, the main beam 16 adopts a steel beam structure.

[0032] Furthermore, refer to Figure 11 The specific operation of the main beam 16 cable hanging and cantilever closure in step S5 includes the following steps: S501: The stay cable 20 is hoisted to the cable guide position of the main beam 16 using the converted tower crane 14; one end of the stay cable 20 passes through the cable guide of the main beam 16, and the other end is connected to the cable saddle at the top of the main tower 5. Jacks are used to tension the stay cable 20. During tensioning, a total station is used to monitor the alignment and elevation of the main beam 16, and the tension is adjusted according to the monitoring data (tensioning is performed in stages according to the design tensioning sequence); after tensioning to the design control stress, the stay cable 20 is fixed to the anchor plate of the main beam 16 using anchorages, and the anchorages are protected (applied anti-corrosion grease, and a protective cover is installed).

[0033] S502: Two girder erection cranes 17 are installed on the main beam 16 of the support 15 on the pier top and side. The girder erection cranes 17 lift the main beam 16 segments of the steel beam structure from the prefabrication yard and hoist the segments to the cantilever end docking position. The segment docking is fixed by a combination of welding and high-strength bolts. After each main beam 16 segment is erected, the inclined cable 20 is hoisted and the cable is hung simultaneously by the converted tower crane 14 (the process is the same as the first cable hanging). The alignment of the main beam 16 is adjusted by tensioning the inclined cable 20 to avoid excessive deflection at the cantilever end of the main beam.

[0034] S503: When the cantilever ends on both sides of the main beam 16 are constructed to the designed position of the closure section, the cantilever erection is stopped, the steel joint surfaces on both sides of the closure section are cleaned and rust is removed, the positioning device for the closure section (such as steel tie rods and jacks) is installed, and after the steel beam closure section is hoisted into place, it is fixed by full penetration welding and high-strength bolts. The girder erecting crane 17, the converted tower crane 14, elevator #2 1201 and the initial construction elevator 8 are dismantled, debris on the top surface of the main beam 16 is cleaned, and the alignment and elevation of the main beam 16 are finally inspected. After acceptance, the subsequent bridge deck construction stage begins.

[0035] Example 2: Reference Figures 12-21 This embodiment provides a specific structural configuration of a tower crane conversion mechanism, which includes a support frame 1, a tower crane conversion connecting frame 2, an elevator conversion connecting frame 3, and a leveling component 4. The support frame 1 is a frame structure, and its bottom is fastened to the pre-embedded bolts of the support platform 6 by nuts. The tower crane conversion connecting frame 2 is sleeved on the outer periphery of the support frame 1, and its top connecting plate 201 (with bolt holes) is adapted to the flange at the bottom of the tower crane body and is connected by high-strength bolts. The elevator conversion connecting frame 3 is sleeved inside the support frame 1, and its top connecting plate 301 (with elongated holes for easy fine adjustment) is adapted to the mounting plate at the bottom of the elevator guide rail frame and is also fixed by bolts.

[0036] The supporting frame 1 includes frame 106, reinforcing angle plate 101, reinforcing plate 102, transition pad 103, compensating pad 104, and reinforcing rib 105. Frame 106 is the main frame of the supporting frame 1, made of Q355B steel spliced ​​into a rectangular frame. It is the core component of the supporting frame 1 that bears the load of the tower crane transfer connection frame 2 and the elevator transfer connection frame 3. Its dimensions are designed according to the installation space of the support platform 6 or bracket A11. The reinforcing angle plate 101 is a right-angled triangular steel component, made of the same material as frame 106 of the supporting frame 1. It is mainly set at the corners of frame 106. Two reinforcing angle plates 101 are symmetrically welded at each corner, and are located on the adjacent sides of the corner of frame 106. The two right-angled sides of the reinforcing angle plate 101 are respectively attached to the horizontal and vertical plates of frame 106, with the attachment length being 1.5 times the height of the steel section. Double-sided full welding process is used. The reinforcing angle plate 101 is used to enhance the torsional and bending resistance of the corner joints of the frame 106, preventing weld cracking or steel deformation at the corners due to stress concentration when the support frame 1 is subjected to the vertical loads of tower cranes and elevators. The reinforcing plate 102 is a rectangular steel plate, evenly distributed along the middle of the side wall of the vertical members of the frame 106. One reinforcing plate 102 is welded at intervals on each vertical member, and all are fully welded to form a "lateral support" structure. Its core function is to improve the lateral stiffness of the frame 106, preventing the support frame 1 from undergoing lateral bending deformation due to horizontal vibrations generated during tower crane operation (such as when lifting heavy objects and rotating) or in strong winds, thus ensuring the overall stability of the support frame 1. A transition pad 103 is placed between the top of frame 106 and frame 303 of the elevator transfer frame 3. By adjusting the thickness of the transition pad 103 to accommodate the deviation between frame 106 and frame 303, a tight fit between frame 106 and frame 303 is ensured, guaranteeing the stable placement of the elevator transfer frame 3. A compensation pad 104, a thin steel plate, is attached to the inner wall of frame 106 and directly abuts against the outer wall end face of the elevator transfer frame 3, preventing localized stress concentration. A reinforcing rib 105, a triangular steel rib, is welded longitudinally to the inner wall of frame 106 at intervals, with both ends welded and fixed to the upper and lower crossbars of frame 106. This enhances the vertical bending resistance of frame 106 and prevents deformation under elevator load.

[0037] The tower crane conversion frame 2 includes a connecting plate 201, a level 202, a reinforcing rib 203, a compensating pad 204, and a frame 205. The reinforcing rib 203 is a strip steel plate, mainly welded to the inner wall of the frame 205. It is evenly arranged along the axial direction of the frame 205, with 2-3 reinforcing ribs welded to each side. Its function is to strengthen the rigidity of the frame 205, preventing the concentrated load (including the weight of the hoisted object) of the initial tower crane 7 and the converted tower crane 14 from acting on the frame 205, thus avoiding deformation of the frame 205 and ensuring that the tower crane load is stably and evenly transferred to the frame 205. Frame 205 is a rectangular frame that fits the outer perimeter of Frame 106. It is made of the same type of steel as Frame 106. When it is fitted onto the outside of Frame 106, a 2-3mm fine-tuning gap is reserved to facilitate subsequent adjustment of the levelness using the leveling component 4. Compensation shim 204 is placed between the inner wall of Frame 205 and the outer wall of Frame 106. By adding or removing compensation shim 204, the fitting gap between Frame 205 and Frame 106 is eliminated, ensuring that the tower load of the initial tower crane 7 or the converted tower crane 14 is evenly transferred to Frame 106, and avoiding localized wear of connecting plate 201.

[0038] The elevator transfer frame 3 includes a second connecting plate 301, a third reinforcing rib 302, and a third frame 303. The third frame 303 is a rectangular steel frame and is the core load-bearing component of the elevator transfer frame 3. Its vertical height is consistent with the inner vertical height of the first frame 106 of the supporting frame 1, and its horizontal width and length are adapted to the inner horizontal dimensions of the first frame 106 (ensuring no significant swaying after nesting). The second connecting plate 301 is a rectangular steel plate, horizontally welded to the top of the third frame 303. Its top surface is parallel and aligned with the bottom mounting plate of the elevator guide rail frame, and the elongated holes on the second connecting plate 301 correspond one-to-one with the bolt holes on the mounting plate of the elevator guide rail frame. The third reinforcing rib 302 is a strip steel, evenly arranged along the axial direction of the third frame 303, with 2 to 3 reinforcing ribs 302 on each side, forming an overall "diagonal brace" shape.

[0039] The leveling assembly 4 is provided in four sets, located in the front, back, left and right directions of the support frame 1, and connected to the four sides of the bottom surface of the tower crane conversion frame 2. The leveling assembly 4 specifically includes a fixed base 401, a lifting platform 402, a wedge block 403, a limiting block 404, and a movable rod 405. The fixed base 401 is connected to the bottom of the support frame 1 by bolts. One end of the lifting platform 402 is embedded in the through groove of the fixed base 401, and the other end directly supports the bottom of the tower crane conversion frame 2. The wedge block 403 is located in the through groove of the fixed base 401 and fits against the inclined surface of the bottom of the lifting platform 402. The limiting block 404 is fixed to the end of the fixed base 401 by bolts. After the movable rod 405 passes through the threaded through hole of the limiting block 404, its end protrusion is embedded in the cavity of the wedge block 403.

[0040] In this embodiment, the tower crane conversion mechanism can be stably deployed in two key scenarios: the connection between tower crane #1 and the foundation 6, and the installation and transfer of the additional construction elevator 12 and bracket A11. In the initial installation scenario of tower crane #1 (701), the installation carrier is platform 6. The core is to achieve a stable connection between tower crane #1 (701) and platform 6 and initial leveling through the tower crane conversion mechanism, laying the foundation for subsequent synchronous climbing. During actual construction, the positions of tower crane #1 (701) and tower crane #2 (702) can be interchanged. This invention describes the situation as tower crane #1 (701) changing position while tower crane #2 (702) remains unchanged. Alternatively, tower crane #1 (701) can remain unchanged while tower crane #2 (702) changes position. In this case, tower crane #2 (702) is connected to the tower crane conversion mechanism, and tower crane #1 (701) can be directly installed on platform 6. First, align the bottom flange of tower crane #1 (701) with the connecting plate 201 at the top of the tower crane conversion frame 2 (connecting plate 201 has pre-set bolt holes matching the tower crane flange), and insert high-strength bolts (not tightened yet, leaving room for fine-tuning), achieving the initial connection between tower crane #1 (701) and the tower crane conversion mechanism.

[0041] When installing tower crane #1 701, the horizontal and longitudinal level deviations of the tower crane body are read using the level 202 on the outer periphery of the tower crane conversion connecting frame 2. If the tower body tilts towards the larger mileage side, the movable rod 405 of the larger mileage side leveling component 4 is turned clockwise. Because the movable rod 405 is threadedly connected to the limit block 404, when turned, the movable rod 405 pushes the wedge block 403 axially. The upper end face of the wedge block 403 is inclined and fits against the bottom inclined face of the lifting platform 402. When the wedge block 403 slides, it pushes the lifting platform 402 upward, causing the larger mileage side end of the tower crane conversion connecting frame 2 to rise until the level 202 shows that the deviation meets the standard. After leveling, let it stand for 5 minutes. After verifying that the level is correct, tighten the high-strength bolts between the tower crane body and the connecting plate 201, and at the same time tighten the anti-loosening nut of the movable rod 405 to lock the leveling state.

[0042] In the scenario of tower crane transfer and installation using bracket A11, the installation carrier is bracket A11 on the outer side of the tower body. The core is to adapt the tower crane conversion mechanism to the non-pillar installation environment, eliminate installation deviations caused by construction errors of bracket A11, and ensure the stability of tower crane 14 after conversion. First, use tower crane #2 (702) to disassemble tower crane #1 (701) into tower body segments, and then lift each segment to bracket A11. Align the flange of the bottom tower body segment with the connecting plate 201 of the tower crane conversion frame 2, insert high-strength bolts (do not tighten them yet), and then assemble the upper tower body segment by segment (each segment is secured with temporary guy ropes to prevent tipping). The outer circumferential sleeve design of the tower crane conversion frame 2 provides greater installation and operation space, facilitating the connection of tower body segments, while ensuring that the tower load can be transferred to the support frame 1 through the connection frame.

[0043] It should be noted that because bracket A11 is located on the outside of main tower 5, it is easily affected by the construction errors of main tower 5 and the welding deformation of bracket A11. The leveling component 4 needs to work together to correct the tilt of bracket A11 and the installation deviation of tower crane. The level of the top surface of bracket A11 and the level of the top surface of tower crane conversion frame 2 are monitored simultaneously using level instrument 202. If the top surface of bracket A11 tilts horizontally (the lower side is the small mileage side) and the tower crane body tilts synchronously, it is necessary to distinguish between the deviation of the bracket itself and the deviation of the equipment installation. In response to the tilt of the bracket and the deviation of the tower crane, operate the leveling components 4 on both sides. On the small mileage side (lower side), turn the movable rod 405 clockwise to push the wedge block 403 to lift the lifting platform 402 and raise the small mileage side of tower crane conversion frame 2. On the high mileage side (higher side), turn the movable rod 405 counterclockwise to pull the wedge block 403 backward. The lifting platform 402 descends under the weight of the tower body until the level instrument 202 shows that the level of tower crane conversion frame 2 meets the standard. After leveling, in addition to tightening the high-strength bolts of the tower, the torque of the connecting bolts between bracket A11 and the main tower 5 needs to be checked. After testing the jacking through the tower crane jacking system and observing that the reading of the level 202 has not changed, the tower crane attachment frame is installed and connected to the main tower 5.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method of arranging a tower crane elevator for construction of a main tower and a main girder of a cable-stayed bridge, characterized in that, Includes the following steps: S1. The main tower (5) is segmented and installed with the initial tower crane (7) and the initial construction elevator (8); the initial tower crane (7) includes tower crane #1 (701) and tower crane #2 (702); the initial construction elevator (8) and tower crane #2 (702) are directly installed on the pier (6), and tower crane #1 (701) is installed on the pier (6) through the tower crane conversion mechanism; S2. The climbing formwork construction of the main tower (5) is synchronized with the initial tower crane (7) and the initial construction elevator (8). During the climbing formwork construction of the main tower (5), bracket A (11) is installed on the main tower (5), and elevator #2 (1201) is directly installed on bracket A (11). Elevator #3 (1202) is installed on bracket A (11) through the tower crane conversion mechanism. S3, tower crane conversion and main tower (5) capping; including: disassembling elevator #3 (1202) from the corresponding tower crane conversion mechanism, disassembling tower crane #1 (701) from the corresponding tower crane conversion mechanism, disassembling tower crane #1 (701) through tower crane #2 (702) and installing it at the corresponding position of elevator #3 (1202); S4, pier-side support (15) erection and main beam (16) initial construction; S5, main beam (16) cable hanging and cantilever closure.

2. The method for arranging tower cranes for the construction of the main tower and main beam of a cable-stayed bridge according to claim 1, characterized in that, In step S4, the top height of the initial construction elevator (8) is adjusted to be below the bottom surface of the main beam (16), and the No. 2 tower crane (702) is dismantled by the tower crane (14) after conversion.

3. The method for arranging tower cranes for the construction of the main tower and main beam of a cable-stayed bridge according to claim 1, characterized in that, The tower crane conversion mechanism includes: The support frame (1) is connected at its bottom to the pre-embedded bolts on the support platform (6) or bracket A (11); The tower crane conversion connection frame (2) is sleeved on the outer periphery of the support frame (1), and the top is provided with a connection plate (201) that is adapted to connect with the bottom of the tower body of the No. 1 tower crane (701). The elevator conversion connecting frame (3) is sleeved inside the support frame (1), and the top is provided with a connecting plate 2 (301) that is adapted to connect with the bottom of the guide rail frame of the No. 3 elevator (1202).

4. The method for arranging tower cranes for the construction of the main tower and main beam of a cable-stayed bridge according to claim 3, characterized in that, A leveling component (4) is provided between the bottom of the support frame (1) and the bottom of the tower crane conversion frame (2), and a level (202) is also provided on the outer periphery of the tower crane conversion frame (2).

5. The method for arranging tower cranes for the construction of the main tower and main beam of a cable-stayed bridge according to claim 4, characterized in that, The leveling component (4) includes: The fixed base (401) is detachably connected to the bottom of the support frame (1) and has a through groove that passes through the fixed base (401). The lifting platform (402) has a sloping bottom and one end is slidably disposed in the through groove opened in the fixed base (401), while the other end abuts against the bottom end face of the tower crane conversion connection frame (2). The wedge block (403) has a wedge-shaped surface structure on its upper end that is adapted to the inclined surface, and is slidably disposed in the through groove.

6. The method for arranging tower cranes for the construction of the main tower and main beam of a cable-stayed bridge according to claim 5, characterized in that, The leveling component (4) also includes: The limiting block (404) has a threaded through hole communicating with the through groove and is detachably connected to the fixed base (401); The movable rod (405) is threadedly connected to the threaded through hole. One end is provided with a protrusion, which is movably disposed in the cavity opened by the wedge block (403). The other end passes through the threaded through hole.

7. A tower crane conversion mechanism for the construction of the main tower and main girder of a cable-stayed bridge, characterized in that, This includes the tower crane conversion mechanism used in the method as described in any one of claims 1 to 6.

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