A prestressing construction method of a bidirectional consolidation strut rod plus through-type inhaul cable beam string structure

Abstract

The application discloses a prestress construction method of a bidirectional fixed strut rod plus through-type inhaul cable beam string structure, which comprises the following steps: in the deepening design stage, the connecting joint of the strut rod and the upper steel beam is designed as a pin shaft hinged joint; in the processing and manufacturing stage, the upper end part of the strut rod is split into at least two separable parts, and a site splicing structure is reserved; in the construction stage, the upper end of the strut rod is kept in a hinged state, the installation of the through-type inhaul cable and the prestress tension are completed; after the tension is completed, the split parts are fixedly connected, so that the upper end of the strut rod is converted into a rigid joint state; and finally, the rigid joint tie rod is installed to complete the system conversion. The node conversion process of "hinged first and rigid later" is adopted, the problem that the prestress cannot be effectively conducted in the bidirectional fixed strut rod system is solved, the precise prestress introduction of each section can be realized without breaking the inhaul cable, and the additional internal force of the strut rod and the unbalanced force of the cable clamp are effectively reduced. The application has the advantages of convenient construction, good economy, beautiful building and the like.

Description

Technical Field

[0001] This invention relates to the field of steel structure construction, and in particular to a prestressed construction method for a bidirectional fixed strut and through-type cable tensioned beam structure. Background Technology

[0002] The tensioned beam structure consists of upper compression-bending members, lower tension members, and intermediate vertical struts. It is a self-balancing force system with advantages such as light weight and high load-bearing capacity, and is widely used in the field of large-span spatial structures.

[0003] In recent years, with the increasing demand for efficient building space utilization, the design span of tensioned beams has been continuously expanding. However, with the increase in span, the compression-bending-torsion coupling effect of tensioned beams under high stress conditions has been significantly aggravated, and the structure's sensitivity to the torsional stiffness of out-of-plane struts has increased dramatically. The traditional upper-end hinged strut design is no longer sufficient to meet the corresponding constraint requirements. Therefore, it is necessary to design the top of the strut as an out-of-plane rigid joint and to set rigid tie rods outside the plane of the upper chord to ensure the coordinated stability of the cable-stayed system and the upper chord through double constraints. At the same time, cable clamps are used to fix the continuous cables in sections, allowing for differentiated prestressing in different sections of the cables, thereby achieving the design goals of high safety, high aesthetics, and good economy.

[0004] However, in the aforementioned tensioned beam structure with bidirectional fixed struts and continuous cables, the prestress cannot be effectively transferred due to the limitation imposed by the bidirectional fixed struts. Furthermore, during tensioning, significant additional stress and unbalanced forces are generated inside the struts and at both ends of the cable clamp nodes. This problem has become a key engineering challenge restricting the widespread application of this type of structure. In existing technologies, the traditional approach is to adjust the design by breaking the cables along the struts, and then anchoring and tensioning them in sections. However, this approach not only results in high engineering costs and poor architectural aesthetics but also leads to low construction efficiency, failing to balance practicality and economy.

[0005] Therefore, designing a construction method that can conveniently and accurately apply prestress, reduce the additional internal forces generated by the struts during tensioning, and reduce the unbalanced forces on both sides of the cable clamp for this type of structural system is of great significance for engineering applications. Summary of the Invention

[0006] This invention aims to solve the common problem of prestress transmission failure in tensioned beam structures with bidirectional fixed struts and continuous cables during construction, and proposes a construction method suitable for this type of structural system. This method enables precise application of prestress in different cable sections, reduces additional internal forces generated by the struts during tensioning, and lowers the unbalanced forces on both sides of the cable clamps. It is highly feasible and convenient, and the completed construction conforms to the original design.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a prestressed construction method for a bidirectional fixed strut-and-through cable-stayed tensioned beam structure, comprising the following steps: During the detailed design phase, the connection node between the strut and the upper steel beam was designed as a pin hinge node. During the manufacturing process, the upper part of the support rod is disassembled into at least two separable components, with provisions made for on-site assembly. During the construction phase, the upper end of the strut is kept in a pin-hinged state to complete the installation and prestressing tensioning of the through cable; After the prestressing is completed, the disassembled components are fixedly connected by the on-site splicing structure, so that the upper end of the strut changes from a hinged state to a rigid state. Install out-of-plane rigid tie rods to complete the structural system conversion.

[0008] Furthermore, the separable component is a U-shaped assembly, the length of which is designed to be the actual required length minus the weld gap, and then minus the length deviation caused by the rotation angle that the strut may produce under unbalanced force. The rotation angle ranges from 1° to 3°.

[0009] Furthermore, the structure employs cable clamps to segmentally fix the continuous cable; the cable clamp includes an upper clamp plate and a lower clamp plate, wherein: The upper clamp plate of the cable clamp is fixedly connected to the lower end of the strut. The bottom of the upper clamp plate is provided with a continuous groove along the direction of the cable, and the two ends of the groove are open. The lower clamping plate of the cable clamp has a U-shaped structure with a tenon in the middle and flanges on both sides. The length of the tenon is less than the length of the groove in the upper clamping plate. The lower clamp plate of the cable clamp is inserted into the groove from bottom to top, lifted upwards, and then locked and fixed with high-strength bolts.

[0010] Furthermore, the cable is prestressed in the factory and the center point of the cable clamp, the installation line and the inspection line are marked on the cable body; during on-site installation, the cable is pulled through the full-length groove of the upper clamp plate of the cable clamp. When the marked position of the cable clamp reaches the position of the support rod, the lower clamp plate of the cable clamp is inserted into the groove from bottom to top and locked and fixed.

[0011] Furthermore, the pin hinge node includes a pin and an ear plate. Through full-process construction simulation calculation, the most unfavorable stress parameters of the pin and ear plate during tensioning are extracted, and the design and selection of the pin and ear plate are completed accordingly. At the same time, stiffening plates are set at the corresponding stress positions inside the strut and the upper steel beam.

[0012] Furthermore, a temporary support system is erected before construction. The temporary support system adopts a portal frame or a lattice support frame with a hollow top. The pin hinge nodes, struts, and cable clamps are assembled on the ground together with the upper steel beams and then hoisted into place as a whole.

[0013] Furthermore, the total deformation of the upper steel beam was calculated by simulating the entire construction process, and the support system was used for pre-cambering. The camber value was calculated as "the deformation value of the final construction step - the deformation value of the first forming + 20mm + the compression deformation value of the support frame".

[0014] Furthermore, before tensioning the cables, a leveling single tube is installed between the top of the support frame and the upper steel beam; before tensioning, ensure that the weld between the leveling single tube and the upper steel beam is cut open and the temporary support plate is removed so that the structural constraint state is consistent with the theoretical calculation; adopt the tensioning method of "force and shape dual control" to complete the cable tensioning operation step by step.

[0015] Furthermore, after the prestressing tensioning is completed and the test is passed, the temporary support system will be unloaded first, and then the disassembled components will be welded and fixed.

[0016] Compared with existing technologies, this invention has the following advantages: The invention employs a "hinged-then-rigid" node conversion process, successfully solving the prestressing application problem in bidirectional fixed strut-supported tensioned beam structures with continuous cables, ensuring the smooth implementation and widespread application of this type of structure. Compared to existing technologies that are limited by construction processes and require segmented cable installation, this method eliminates the need to break the cables, enabling convenient and precise prestressing application, effectively reducing the additional internal forces generated by the struts during tensioning, and significantly reducing the unbalanced forces on both sides of the cable clamps. It also boasts multiple advantages, including a fast and convenient construction process, significantly reduced project costs, and the ability to maintain an aesthetically pleasing architectural design without increasing the size of the cable clamps, thus balancing structural practicality, economy, and architectural aesthetics. Attached Figure Description

[0017] Figure 1 This is a three-dimensional schematic diagram of the bidirectional fixed strut and through-type cable tensioned beam structure according to an embodiment of the present invention; Figure 2 This is a schematic elevation view of the bidirectional fixed strut and through-type cable tensioned beam structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the construction process of the bidirectional fixed strut and through-type cable tensioned beam structure according to an embodiment of the present invention; Figure 4 This is a three-dimensional schematic diagram of the upper pin hinge node of the strut according to an embodiment of the present invention; Figure 5 This is a three-dimensional schematic diagram of the upper rigid connection node of the strut according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the upper pin hinge node of the strut according to an embodiment of the present invention (before the disassembled parts are installed). Figure 7 This is a schematic diagram of the upper rigid connection node of the strut according to an embodiment of the present invention (disassembled component installation state). Figure 8 This is a schematic diagram of the upper split component (U-shaped assembly) of the upper pin of the strut according to an embodiment of the present invention; Figure 9 This is a three-dimensional schematic diagram of the cable clamp described in an embodiment of the present invention; Figure 10 This is a schematic diagram of the cable clamp elevation structure according to an embodiment of the present invention; Figure 11 This is a schematic diagram of the cable clip in use according to an embodiment of the present invention.

[0018] Attached diagram labels: 1. Upper steel beam; 2. Support rod; 3. Through-type cable; 4. Structural column; 5. Support; 6. Temporary support system; 7. Leveling single pipe; 8. Ear plate; 9. Pin shaft; 10. Stiffening plate; 11. U-shaped component; 12. Upper clamp plate of cable clamp; 13. Lower clamp plate of cable clamp. Detailed Implementation

[0019] The following is in conjunction with the appendix Figures 1 to 11 The present invention provides a more detailed description of the specific implementation method of a prestressed construction method for a bidirectional fixed strut and through-type cable tensioned beam structure.

[0020] like Figure 1 , Figure 2 As shown, the present invention relates to a bidirectional fixed strut and through-type cable tensioned beam structural system, including an upper steel beam 1, struts 2, through-type cables 3, structural columns 4, and supports 5. The upper steel beam 1 forms a self-balancing force system through the struts 2 and the through-type cables 3, and is connected to the structural columns 4 and supports 5 to form a stable structure.

[0021] Node detailed design: such as Figure 4 , Figure 6 As shown, during the detailed design phase, the upper node of strut 2 is designed as a pin-hinged node, including ear plate 8 and pin 9. Through full-process construction simulation calculations, the most unfavorable stress parameters of pin 9 and ear plate 8 during tensioning are extracted, and the design and selection of pin and ear plate are completed accordingly. At the same time, cross stiffening plates 10 are installed at corresponding stress positions inside strut 2 and upper steel beam 1 for structural reinforcement. The stiffening plates and related stress-bearing components are designed with a safety margin of not less than 2 times.

[0022] Disassembled component processing: such as Figure 5 , Figure 7 , Figure 8 As shown, during the manufacturing stage, the upper part of the strut is disassembled into at least two separable components, with provisions for on-site assembly. In this embodiment, the separable components are in the form of U-shaped components 11, that is, components that divide the upper part into two U-shaped sections along the axial direction of the strut, with pre-designed butt welding bevels. After tensioning, the two U-shaped components are fixed by on-site welding, restoring the upper part of the strut to a continuous structure.

[0023] The length of the U-shaped component is calculated using the following formula: L_component = L_theoretical - Δ_weld - Δ_angle, where The Δ rotation angle is the length deviation corresponding to the possible rotation angle of the strut under unbalanced force. It is determined based on the construction simulation results and has a value range of 1° to 3°.

[0024] Cable clamp structure design: such as Figure 9 , Figure 10 , Figure 11 As shown, the cable clamp includes an upper clamp plate 12 and a lower clamp plate 13.

[0025] The upper clamp plate 12 of the cable clamp is connected to the lower end of the strut 2, and a continuous groove along the direction of the cable is provided at the bottom of the upper clamp plate. The groove has a rectangular or trapezoidal cross-section, is open at both ends, and has a depth greater than the radius of the cable.

[0026] The lower clamping plate 13 of the cable clamp has a U-shaped structure with a tenon in the middle and flanges on both sides. The cross-sectional shape of the tenon matches the cross-sectional shape of the groove in the upper clamping plate. The length of the tenon is less than the length of the groove in the upper clamping plate, with a difference range of 10-30mm, to reserve space for insertion from bottom to top.

[0027] Bolt holes are provided at corresponding positions on the two side flanges and the upper clamping plate, and high-strength bolts are used for locking and fixing.

[0028] Cable clip installation method: such as Figure 11 As shown, the installation of the lower clamp plate of the cable clamp includes the following steps: Step 1: Cable insertion. The cable is pulled through the full-length groove of the upper clamping plate 12. At this time, the lower clamping plate 13 is not installed, and the cable is placed freely in the groove.

[0029] Step 2: Alignment. When the cable clamp mark on the cable reaches the support rod position, align the tenon of the lower clamp plate with the opening at one end of the groove in the upper clamp plate.

[0030] Step 3: Insert from bottom to top. Insert the lower clamping plate tenon into the groove from bottom to top, covering the cable.

[0031] Step 4: Lift up. Lift the lower clamping plate up so that the tenon presses against the cable and presses the cable against the top of the groove on the upper clamping plate.

[0032] Step 5: Tighten the bolts. Insert high-strength bolts from both sides and tighten them to complete the cable clamp fixation.

[0033] The entire construction process includes the following steps: Step 1: Erect a temporary support system like Figure 3As shown, a temporary support system 6 is constructed to support the installation of the upper steel beam of the tensioned beam. The temporary support system adopts a portal frame or a lattice support frame with a hollowed-out top, reserving reasonable operating space for subsequent cable threading and installation operations.

[0034] Step 2: Ground assembly The pin-hinged joint, strut 2, and cable clamp plate 12 are assembled with the upper steel beam 1 on the ground. The total deformation of the upper steel beam during the entire construction process is calculated through simulation, and pre-cambering is performed using the temporary support system 6. The camber value is determined by the principle of "final construction step deformation value - one-time forming deformation value + 20mm + support frame compression deformation value". Among them, "final construction step deformation value" refers to the total deformation of the structure after construction, calculated according to the construction simulation; "one-time forming deformation value" refers to the structural deformation calculated according to the design state one-time forming; "20mm" is the construction adjustment allowance; and "support frame compression deformation value" refers to the compression deformation of the temporary support system under load.

[0035] During the ground assembly stage, the upper steel beams are also pre-cambered in sections. The camber value is fi = F × (Li / Di), where: fi is the camber value of the i-th steel beam section; F is the overall camber value of the corresponding support point of the section; Li is the length of the steel beam section; and Di is the distance from the end of the section to the support point.

[0036] Step 3: Overall hoisting The assembled upper steel beam 1, along with its connected struts 2, pin hinge joints, and cable clamp upper plate 12, were hoisted into place as a whole. The upper steel beam 1 was then spot-welded to the leveling single pipe 7 for fixation.

[0037] Step 4: Cable Installation Using construction machinery such as truck cranes, winches, and hydraulic jacks, and in conjunction with ground cable reel, the fixed end of the through cable 3 is first installed in place, and then the tensioning end is pulled to the design position.

[0038] During the traction process, the cable passes through the continuous groove of each upper clamp plate 12 in sequence. When the position of the cable clamp mark on the cable reaches the position of the corresponding support rod 2, the lower clamp plate 13 of the cable clamp is installed and locked in the manner described above.

[0039] Step 5: Prestressing tensioning Before formal tensioning, complete the preliminary acceptance and preparation work to ensure that all welds pass the acceptance test, the top leveling single pipe of the support system 6 is cut open, and the temporary clamps of the supports are removed, so that the constraint state of the main structure is consistent with the theoretical calculation state.

[0040] A dedicated tensioning fixture is installed at the tensioning end of the cable, and a tensioning method with both force and shape control is adopted to complete the cable tensioning operation step by step. At this time, the upper node of the strut 2 is in a hinged state and can rotate freely, effectively releasing the additional bending and torsional stress generated by tensioning.

[0041] Step 6: Support Uninstallation After the prestressing of the cables is completed and the test is passed, the unloading of the temporary support system 6 will be carried out.

[0042] Step 7: Node Conversion After unloading, the disassembled components are fixedly connected using the pre-reserved on-site splicing structure. In this embodiment, the two U-shaped components 11 reserved at the pin shaft are assembled on-site and firmly fixed by welding. At this point, the nodes on the strut smoothly transition from the hinged state during the tensioning stage to the out-of-plane rigid connection state during service.

[0043] Step 8: System fixation Finally, install the rigid tie rods outside the strut plane. Through the dual protection of rigid joints and tie rod constraints, the cable-stayed system and the upper chord work together to ensure the structure meets design requirements.

[0044] The realization of prestressed tuning: "Tuning" refers to the process of applying differentiated prestress to the cable sections to make the internal force distribution and deformation state of the tensioned beam structure reach the design optimal state.

[0045] During the prestressing tensioning stage, because the nodes on the struts are hinged, each strut can rotate freely with the deformation of the cables. At this time, by utilizing the initial length difference of the cables between the cable clamps (controlled during factory processing), the differentiated and precise introduction of prestress in each section can be achieved by tensioning only one end of the structure. After tensioning is completed, the cable forces on both sides of each cable clamp reach the equilibrium state required by the design, thus completing the "tuning" of the structure.

[0046] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A prestressed construction method for a bidirectional fixed strut-supported tensioned beam structure with continuous cable, characterized in that, Includes the following steps: During the detailed design phase, the connection node between the strut and the upper steel beam was designed as a pin hinge node. During the manufacturing process, the upper part of the support rod is disassembled into at least two separable components, with provisions made for on-site assembly. During the construction phase, the upper end of the strut is kept in a pin-hinged state to complete the installation and prestressing tensioning of the through cable; After the prestressing is completed, the disassembled components are fixedly connected by the on-site splicing structure, so that the upper end of the strut changes from a hinged state to a rigid state. Install out-of-plane rigid tie rods to complete the structural system conversion.

2. The prestressed construction method for a bidirectional fixed strut-and-through cable-stayed tensioned beam structure according to claim 1, characterized in that: The separable component is a U-shaped assembly. Its length is designed to be the actual required length minus the weld gap, and then minus the length deviation caused by the rotation angle that the strut may produce under unbalanced force. The rotation angle ranges from 1° to 3°.

3. The prestressed construction method for a bidirectional fixed strut-and-through cable-stayed tensioned beam structure according to claim 1, characterized in that: The structure uses cable clamps to fix the continuous cable in sections; the cable clamp includes an upper clamp plate and a lower clamp plate, wherein: The upper clamp plate of the cable clamp is fixedly connected to the lower end of the strut. The bottom of the upper clamp plate is provided with a continuous groove along the direction of the cable, and the two ends of the groove are open. The lower clamping plate of the cable clamp has a U-shaped structure with a tenon in the middle and flanges on both sides. The length of the tenon is less than the length of the groove in the upper clamping plate. The lower clamp plate of the cable clamp is inserted into the groove from bottom to top, covering the cable, and then lifted upwards and locked in place with high-strength bolts.

4. The prestressed construction method for a bidirectional fixed strut-and-through cable-stayed tensioned beam structure according to claim 3, characterized in that: The cable is prestressed in the factory and the center point of the cable clamp, the installation line and the inspection line are marked on the cable body. During on-site installation, the cable is pulled through the full-length groove of the upper clamp plate of the cable clamp. When the marked position of the cable clamp reaches the position of the support rod, the tenon of the lower clamp plate of the cable clamp is inserted into the groove from bottom to top and locked in place.

5. The prestressed construction method for a bidirectional fixed strut-and-through cable-stayed tensioned beam structure according to claim 1, characterized in that: The pin hinge node includes a pin and a lug plate. Through full-process construction simulation calculation, the most unfavorable stress parameters of the pin and lug plate during tensioning are extracted, and the design and selection of the pin and lug plate are completed accordingly. At the same time, stiffening plates are set at the corresponding stress positions inside the strut and the upper steel beam.

6. The prestressed construction method for a bidirectional fixed strut-and-through cable-stayed tensioned beam structure according to claim 1, characterized in that: Before construction, a temporary support system is erected, which adopts a portal frame or a lattice support frame with a hollow top. The pin hinge joint, struts, cable clamps and plates are assembled on the ground together with the upper steel beam and then hoisted into place as a whole.

7. The prestressed construction method for a bidirectional fixed strut-and-through cable-stayed tensioned beam structure according to claim 1, characterized in that: The total deformation of the upper steel beam was calculated by simulating the entire construction process, and the pre-camber was carried out using the support system. The camber value was calculated as "the deformation value of the final construction step - the deformation value of the first forming + 20mm + the compression deformation value of the support frame".

8. The prestressed construction method for a bidirectional fixed strut-and-through cable-stayed tensioned beam structure according to claim 1, characterized in that: Before tensioning the cables, a leveling tube is installed between the top of the support frame and the upper steel beam. Before tensioning, ensure that the weld between the leveling tube and the upper steel beam is cut and the temporary support plate is removed so that the structural constraint state is consistent with the theoretical calculation. The tensioning operation is completed step by step using a "force and shape dual control" tensioning method.

9. The prestressed construction method for a bidirectional fixed strut-and-through cable-stayed tensioned beam structure according to claim 1, characterized in that: After the prestressing tensioning is completed and the test is passed, the temporary support system is unloaded first, and then the disassembled components are welded and fixed.

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