Full-rigid-frame concrete segment girder bridge rapid construction method based on machine-girder cooperation

Abstract

The invention discloses a rapid construction method for a full-rigid frame concrete segment girder bridge based on machine-girder cooperation, which comprises the following steps: after setting a T-structure actual unbalanced load and establishing a rigid frame segment girder bridge finite element model, screening out a dangerous segment and a corrected segment which are caused by pier body cracking, and connecting the selected segment girder with a bridge girder erection machine by adopting finish rolling deformed steel bars; the asymmetric load is balanced through the finish rolling deformed steel bars, the stress safety of the pier column is guaranteed, compared with a traditional method for erecting a pier-side support, the construction time and the construction cost are greatly reduced, rapid construction is achieved, the influence of the surrounding road space environment is small, and the application range is wide.

Description

Technical Field

[0001] The present invention relates to the technical field of bridge structure construction. More specifically, the present invention relates to a rapid construction method for a full rigid-frame concrete segmental girder bridge based on the cooperation of machine and girder. Background Art

[0002] When the full rigid-frame concrete segmental girder bridge adopts the construction technology of cantilever erection by a bridge erecting machine, due to reasons such as segment prefabrication errors, asymmetry of the hook release of the bridge erecting machine, and the action of wind loads, unbalanced loads will appear at both ends of the T-structure. The longer the cantilever, the greater the adverse effect. To ensure construction safety and reduce adverse effects, brackets are often erected beside the piers to jointly resist this influence. However, the method of erecting brackets beside the piers takes a lot of man-hours, has a greater impact on the construction progress, and is limited by the existing road traffic environment, and the space that the pier columns can occupy is limited. Considering the structural force requirements and the requirements of construction safety and convenience, there is an urgent need for a rapid and feasible construction method to improve the mechanical properties of the rigid-frame pier columns and reduce the impact on the construction progress and the surrounding road environment. Summary of the Invention

[0003] An object of the present invention is to solve at least the above problems and provide at least the advantages described hereinafter.

[0004] Another object of the present invention is to provide a rapid construction method for a full rigid-frame concrete segmental girder bridge based on the cooperation of machine and girder, so as to solve the technical problem that the existing technology affects the construction efficiency when relying on erecting brackets beside the piers to resist the unbalanced loads during the construction at both ends of the T-structure.

[0005] To achieve these and other advantages in accordance with the present invention, there is provided a rapid construction method for a full rigid-frame concrete segmental girder bridge based on the cooperation of machine and girder, including the following steps: S1. Set up the actual unbalanced load of the current T-structure and establish a finite element model of the rigid-frame segmental girder bridge; S2. Simulate the construction process, take the data combination under the most unfavorable working conditions for the actual unbalanced load of the current T-structure, conduct construction stage analysis, and obtain the hoisting segment that causes the pier body to crack through calculation, which is recorded as the dangerous segment; S3. The legs of the bridge erecting machine are respectively supported on the constructed segmental girders directly above the pier top. Select the segmental girder before the dangerous segment to be erected as the correction segment. Use the bridge erecting machine to construct the segmental girders from the center of the pier top to both ends. When reaching the correction segment, use high-strength threaded steel to connect the correction segment and the bridge erecting machine vertically, and balance the asymmetric loads at both ends of the T-structure through the high-strength threaded steel; S4. Continue to complete the cantilever erection construction of the T-structure. After the construction of one T-structure is completed, disconnect the high-strength threaded steel from the correction segment, and move the bridge erecting machine forward to the next pier. Starting from step S1, repeat all the above operations in sequence.

[0006] Preferably, in step S1, in the extending direction of the T-structure, the unbalanced loads are set as follows: a. The self-unbalanced weight of the beam segment is calculated by reducing 2% on one side and increasing 2% on the other side; b. The unhooked unbalanced load of the beam segment is calculated as 100% of the beam segment weight on one side and 50% of the beam segment weight on the other side; c. The vertical wind load is calculated as 100% of the wind load on one side and 50% of the wind load on one side; After combining the data under the most unfavorable working conditions for the three set unbalanced loads, the construction stage analysis is carried out in step S2.

[0007] Preferably, for the correction segment, it is connected to the corresponding position of the bridge erecting machine through four groups of the above-mentioned high-strength steel bars arranged symmetrically.

[0008] Preferably, after connecting the correction segment and the bridge erecting machine vertically with the high-strength steel bars, the erection working conditions of the dangerous segment are reviewed, and the pier body is segmented vertically. If the tensile stress of each pier body segment is less than the standard value of the tensile strength of the corresponding concrete type, it is considered that the pier body is safe in force.

[0009] Preferably, the bridge erecting machine includes a truss main body. A plurality of legs are arranged at intervals along the longitudinal bridge direction at the bottom of the truss main body. Slide rail frames are symmetrically arranged along the longitudinal bridge direction on the front and rear sides of the legs at the center of the area of the beam segment to be constructed of the truss main body. A pair of support beams are slidably connected together on each side of the slide rail frame. The support beams extend along the transverse bridge direction. A row of tension holes are arranged at intervals along the transverse bridge direction on the support beams. The top of the high-strength steel bar passes upward through one of the tension holes and is successively sleeved with fastening nuts and connected to a tensioning device. The lower end of the high-strength steel bar is connected with a connecting piece for anchoring connection with the top of the beam segment. Between the two ends on the same side of a pair of support beams, a cylindrical hole is opened at one end, and a pin shaft is connected to the other end facing the cylindrical hole. A jacking hole is opened along the transverse bridge direction on the pin shaft, and a plurality of jacking holes are arranged axially on the pin shaft. A positioning card is inserted into one of the jacking holes to fix the distance between the pair of support beams. A distance measuring sensor is arranged between the pair of support beams, a distance measuring sensor is arranged downward at the bottom of the support beam, and the bottom of the support beam is provided with a distance measuring sensor facing the bridge erecting machine leg corresponding to the currently constructed T-structure; Set up a remote control terminal, communicate and connect all distance measuring sensors. Starting from the moment when the previous T-structure begins to hoist the correction segment until after the removal of the fine-threaded steel bars, it is regarded as a monitoring construction time period to monitor the data changes of all distance measuring sensors. During the same monitoring construction time period of the next T-structure, compare with the real-time data obtained by the distance measuring sensors at the corresponding positions to guide the position setting of the fine-threaded steel bars corresponding to the next T-structure, so that the support beam moves along the slide rail frame, determine the distance between a pair of support beams, select the tensioning holes, and position the installation position of the fine-threaded steel bars.

[0010] The present invention has at least the following beneficial effects: After setting the actual unbalanced load of the T-structure and establishing the finite element model of the rigid frame concrete segmental bridge in the rapid construction method of the full rigid frame concrete segmental bridge based on the cooperation of the machine and the beam of the present invention, the dangerous segments and correction segments are calculated by screening the factors causing the pier body to crack. The selected segmental beam is connected to the bridge erecting machine by fine-threaded steel bars. The fine-threaded steel bars are used to balance the asymmetric load, ensuring the safety of the pier column in terms of force. Compared with the traditional method of erecting the pier side support, the construction man-hours and construction costs are greatly reduced, rapid construction is realized, and it is less affected by the surrounding road space environment, with a wide range of applications.

[0011] Other advantages, objectives and features of the present invention will be partially reflected by the following description, and partially will also be understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic flow chart of the rapid construction method of the full rigid frame concrete segmental bridge based on the cooperation of the machine and the beam of the present invention; Figure 2 It is a schematic diagram of the T-structure of the present invention; Figure 3 It is a schematic diagram of the structure of connecting the correction segment to the bridge erecting machine by using fine-threaded steel bars of the present invention; Figure 4 It is a schematic diagram of the force condition of the pier body when the fine-threaded steel bars are not set under the most unfavorable working conditions in the embodiment of the present invention; Figure 5 It is a schematic diagram of the force condition of the upper edge of the pier body when the correction segment is connected to the bridge erecting machine by using fine-threaded steel bars and the 9# erection working condition is rechecked in the embodiment of the present invention; Figure 6 It is a schematic diagram of the force condition of the lower edge of the pier body when the correction segment is connected to the bridge erecting machine by using fine-threaded steel bars and the 9# erection working condition is rechecked in the embodiment of the present invention; Figure 7 It is a schematic diagram of the structure of setting the support beam and the distance measuring sensors in an embodiment of the present invention; Reference numerals in the drawings: 1, bridge erecting machine; 2, pier body; 3, segmental beam; 4, support leg; 5, high-strength threaded steel; 6, truss main body; 7, slide rail frame; 8, support beam; 9, tensioning hole; 10, fastening nut; 11, tensioning facility; 12, pin shaft; 13, jacking hole; 14, positioning fixture; 15, distance measuring sensor. Detailed implementation manners

[0013] The following further describes the present invention in detail with reference to the drawings, so that those skilled in the art can implement it according to the text of the specification.

[0014] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation manners are all conventional methods, and the reagents and materials, unless otherwise specified, can all be obtained from commercial channels; in the description of the present invention, the terms "transverse", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0015] As Figures 1-3 shown, the present invention provides a rapid construction method for a fully rigid-frame concrete segmental beam bridge based on the coordination of the machine and the beam, including the following steps: S1. Set up the actual unbalanced load of the current T-frame, and establish a finite element model of the rigid-frame segmental beam bridge 3. The upper side of the T-frame is divided according to the segmental beam 3, and the pier body 2 is divided at a vertical interval of about 1 m. Among them, the concrete type of the bridge pier is C40, and the concrete type of the pile column is C30. When constructing, the unbalanced loads to be considered for the T-frame include the self-unbalanced weight of the beam segment, the unbalanced load of the beam segment decoupling, and the vertical wind load, and the reaction forces of the tooth blocks, diaphragms, turning blocks, and the support legs 4 of the bridge erecting machine 1 are also considered.

[0016] S2. Simulate the construction process, take the data combination under the most unfavorable working condition for the actual unbalanced load of the current T-frame, conduct a construction stage analysis, and obtain the hoisting segment that causes the pier body 2 to crack through calculation, which is recorded as the dangerous segment.

[0017] S3. The support legs 4 of the bridge erecting machine 1 are respectively supported on the constructed segmental beam 3 directly above the pier top. Select the segmental beam 3 in the previous segment of the dangerous segment as the correction segment, and use the bridge erecting machine 1 to construct the segmental beam 3 from the center of the pier top to both ends. When reaching the correction segment, use the high-strength threaded steel 5 to connect the correction segment and the bridge erecting machine 1 vertically, and balance the asymmetric loads at both ends of the T-frame through the high-strength threaded steel 5.

[0018] S4. Continue to complete the cantilever erection construction of the T-structure. After the construction of one T-structure is completed, disconnect the high-strength threaded steel 5 from the modified segment. Move the bridge girder erecting machine 1 forward to the next pier, and repeat all the above operations in sequence starting from step S1 until the construction of the entire rigid frame bridge is completed.

[0019] The rapid construction method of the all-rigid frame concrete segmental beam 3 bridge based on "machine-beam coordination" proposed by the present invention screens the dangerous segments and modified segments obtained by calculating the cracking of the pier shaft 2 after setting the actual unbalanced load of the T-structure and establishing the finite element model of the rigid frame segmental beam 3 bridge. The selected segmental beam 3 is connected to the bridge girder erecting machine 1 by high-strength threaded steel 5. The high-strength threaded steel 5 is used to balance the asymmetric load, ensuring the safety of the pier column force. Compared with the traditional method of erecting the bracket beside the pier, the construction man-hours and construction costs are greatly reduced, rapid construction is achieved, and it is less affected by the surrounding road space environment, with a wide range of applications.

[0020] In another technical solution, as Figures 4-6 shown, in step S1, in the extending direction of the T-structure, the unbalanced load is set as follows: a. The self-unbalanced weight of the beam segment is calculated by reducing 2% on one side and increasing 2% on the other side. b. The unhooked unbalanced load of the beam segment is calculated as 100% of the beam segment weight on one side and 50% of the beam segment weight on the other side. c. The vertical wind load is calculated as 100% of the calculated wind load on one side and 50% of the calculated wind load on one side. The standard value of the wind load perpendicular to the building surface should be calculated according to the following formula: When calculating the main load-bearing structure, use the formula: wk = βzμsμzWo, where wk is the standard value of the wind load (kN / m 2 ), βz is the wind vibration coefficient at height z, μs is the wind load shape coefficient, μz is the wind pressure height change coefficient, and Wo is the basic wind pressure (kN / ㎡).

[0021] After combining the data under the most unfavorable working conditions of the three set unbalanced loads, perform the construction stage analysis in step S2.

[0022] In another technical solution, as Figures 3-6 shown, for the modified segment, it is connected to the corresponding position of the bridge girder erecting machine 1 through four groups of symmetrically arranged high-strength threaded steel 5.

[0023] In another technical solution, as Figures 3-6 shown, after connecting the modified segment and the bridge girder erecting machine 1 vertically with the high-strength threaded steel 5, review the erection working conditions of the dangerous segment, segment the pier shaft 2 vertically. If the tensile stress of each segment of the pier shaft 2 is less than the standard value of the tensile strength of the corresponding concrete type, it is considered that the pier shaft 2 is safe in force.

[0024] Example 1: In the reconstruction and expansion project of the Jihe Expressway, the beam-column cooperation method of the present invention is used to quickly construct the rigid-frame concrete segmental beam bridge. The corresponding most unfavorable working conditions are as follows: 102% of the self-weight on the left side of Pier 2 and 50% of the vertical wind load (upward); 98% of the self-weight on the right side of Pier 2, including 50% of the self-weight of the assembled segment and 100% of the vertical wind load (upward). A Midas model is established as Figure 2 shown. The concrete type of the bridge pier is C40, and the concrete type of the pile column is C30. Table 1 below shows the standard values and design value requirements for the two types of concrete.

[0025] Table 1 The calculation results are as Figure 4 shown. Through calculation, it is found that the maximum tensile stress of Pier 2 is 7.5 MPa, far greater than the standard tensile strength value of 2.4 MPa for C40; the maximum tensile stress of the pile column is 4.1 MPa, far greater than the standard tensile strength value of 2.01 MPa for C30. There is a risk of cracking in the bridge pier and pile column during the construction stage. Section 9# is the dangerous section, and Section 4# is the correction section. After connecting this section to the bridge erecting machine 1 with the high-strength threaded steel 5, the erection working condition of Section 9# is rechecked. The calculation results of the upper edge of Pier 2 are as Figure 5 shown, and the calculation results of the lower edge of Pier 2 are as Figure 6 shown. It is calculated that both the upper and lower edges of Pier 2 are in compression and the stress is safe, indicating that the present invention can ensure the safety of the pier column stress while realizing rapid construction by using threaded steel instead of the pier side support to balance the asymmetric load.

[0026] If the pier side support is erected according to the existing technology, the bridge erecting machine 1 first hoists the 1# blocks on both sides of the pier. The support can support the 1# block and the 2# block, and then the segments are hoisted in sequence to the maximum cantilever state. The position of the temporary support is determined according to the calculation results under the same most unfavorable load working conditions. The specific calculation results are shown in Table 2 below.

[0027] Table 2 When erecting the 4# block, a temporary support is erected, and the fulcrum is located at the center of the 4# segment. The key calculation results of the temporary support scheme and the tie rod scheme of the bridge erecting machine 1 are compared as shown in Table 3 below.

[0028] Table 3 Due to the relatively large vertical stiffness of the temporary support, each fulcrum will bear the self-weight of about 1200 kN of the segmental beam 3. The maximum compressive stress of Pier 2 is 5.3 MPa, and the maximum vertical deflection is 7.5 mm. The high-strength threaded steel 5 has a relatively small vertical stiffness, has little influence on the alignment of the segmental beam 3, and mainly bears the unbalanced load. The maximum compressive stress of Pier 2 is 7.0 MPa, and the maximum vertical deflection is 8.5 mm, with a relatively large compressive stress reserve.

[0029] In another technical solution, as Figure 3 , 7 shown, the girder erecting machine 1 includes a truss main body 6. A plurality of legs 4 are arranged at intervals along the longitudinal bridge direction at the bottom of the truss main body 6. Slide rail frames 7 are symmetrically arranged along the longitudinal bridge direction on the front and rear sides of the legs 4 where the truss main body 6 is located at the center of the area of the segmental girder 3 to be constructed. A pair of support beams 8 are slidably connected together on each side of the slide rail frame 7. The support beams 8 extend along the transverse bridge direction. A row of tension holes 9 are arranged at intervals along the transverse bridge direction on the support beams 8. The top of the high-strength threaded steel bar 5 passes upward through a tension hole 9 at one place and is successively sleeved with a fastening nut 10 and a connecting tensioning device 11. The lower end of the high-strength threaded steel bar 5 is connected with a connecting piece for anchoring and connecting with the top of the segmental girder 3. Between the two ends on the same side of a pair of support beams 8, a cylindrical hole is opened at one end, and a pin shaft 12 is connected towards the cylindrical hole at the other end. A jacking hole 13 is opened along the transverse bridge direction on the pin shaft 12. A plurality of jacking holes 13 are arranged axially on the pin shaft 12. A positioning clamping member 14 is inserted into one of the jacking holes 13 to fix the distance between a pair of support beams 8. A distance measuring sensor 15 is arranged between a pair of support beams 8, and a distance measuring sensor 15 is arranged downward at the bottom of the support beam 8. The bottom of the support beam 8 is provided with a distance measuring sensor 15 towards the leg 4 of the girder erecting machine 1 corresponding to the currently constructed T-shaped structure; A remote control terminal is set up, which is communicatively connected to all the distance measuring sensors 15. Starting from the hoisting of the correction segment of the previous T-shaped structure until the high-strength threaded steel bar 5 is removed is taken as a monitoring construction time period, and the data changes of all the distance measuring sensors 15 are monitored. During the same monitoring construction time period of the next T-shaped structure, a comparison is made with the real-time data obtained by the distance measuring sensors 15 at the corresponding positions to guide the position setting of the high-strength threaded steel bar 5 corresponding to the next T-shaped structure, so as to move the support beam 8 along the slide rail frame 7, determine the distance between a pair of support beams 8, select the tension hole 9, and position the installation position of the high-strength threaded steel bar 5.

[0030] When the bridge erecting machine 1 continuously performs the cantilever construction of the T-shaped structure in sequence, during the construction time range before and after connecting the correction section to the high-strength threaded steel 5 for the first T-shaped structure, the distance measuring sensor 15 is used for monitoring and transmitted to the remote control terminal for display. It is possible to obtain the changes in the states of the bridge erecting machine 1 and the support beam 8 under the action of the high-strength threaded steel 5 connecting the segment beam 3 during the construction process of the front and rear segment beams 3 of the T-shaped structure, and whether deformation occurs. Within the deformation safety range, by comparing the distance data monitored by the distance measuring sensor 15 within the same time period range for the next T-shaped structure, it is possible to quickly determine the position of the high-strength threaded steel 5 relative to the leg 4 of the bridge erecting machine 1 before connecting the high-strength threaded steel 5. Moreover, the support beam 8 can move along the slide rail frame 7, and multiple tension holes 9 are arranged in the transverse bridge direction. When adjusting the relative position of the high-strength threaded steel 5 and the correction section for the subsequent structural safety requirements, the position of the high-strength threaded steel 5 can also be adjusted in the in-plane space, improving the flexibility of the position adjustment of the high-strength threaded steel 5 and the installation and connection efficiency. Through the lock nut, the tensioning device 11, and the locking structure, the state of the high-strength threaded steel 5 in the vertical direction is adjusted, and the deformation state is continuously monitored during the subsequent cantilever construction process.

[0031] Although the embodiments of the present invention have been disclosed as above, they are not limited to only the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated and described examples here.

Claims

1. A rapid construction method for a full rigid frame concrete segmental beam bridge based on machine-beam collaboration, characterized in that: The steps include: S1. Establish the actual unbalanced load of the current T-structure and build a finite element model of the rigid frame segmental beam bridge; S2. Simulate the construction process, take the data combination under the most unfavorable working condition for the actual unbalanced load of the current T-structure, conduct construction stage analysis, and calculate the hoisting segment that causes the pier body to crack, which is recorded as the dangerous segment; S3. The legs of the bridge erecting machine are supported on the constructed segmental beams directly above the pier top. The segmental beam before the dangerous segment is selected as the correction segment. The bridge erecting machine is used to construct the segmental beams from the center of the pier top to both ends. At the correction segment, the fine-rolled threaded steel is used to vertically connect the correction segment and the bridge erecting machine. The fine-rolled threaded steel is used to balance the asymmetric loads at both ends of the T structure. S4. Continue to complete the T-structure cantilever assembly construction. After the construction of one T-structure is completed, release the connection between the fine-rolled threaded steel bar and the modified segment, and move the bridge-erecting machine forward to the next pier. Starting from step S1, repeat all the above operations in sequence.

2. The rapid construction method of a full rigid frame concrete segmental beam bridge based on machine-beam collaboration as claimed in claim 1 is characterized in that: In step S1, in the extension direction of the T-structure, the unbalanced load is established as follows: a. The unbalanced weight of the beam section itself is calculated by reducing 2% on one side and increasing 2% on the other side; b. Unbalanced load of beam section uncoupling: one side is calculated as 100% of the beam section weight, and the other side is calculated as 50% of the beam section weight; c. Vertical wind load: one side is calculated as 100% of the wind load, and the other side is calculated as 50% of the wind load; After combining the data under the most unfavorable working condition of the three established unbalanced loads, a construction phase analysis is performed in step S2.

3. The rapid construction method of a full rigid frame concrete segmental beam bridge based on machine-beam collaboration as claimed in claim 1 is characterized in that: The correction segment is connected to the corresponding position of the bridge erecting machine through four groups of symmetrically arranged finish-rolled threaded steel bars.

4. The rapid construction method of a full rigid frame concrete segmental beam bridge based on machine-beam collaboration as claimed in claim 1, characterized in that: After the modified section is vertically connected to the bridge-erecting machine using the fine-rolled threaded steel bar, the erection conditions of the dangerous section are checked and the pier body is vertically segmented. If the tensile stress of each section of the pier body is less than the standard value of the tensile strength of the corresponding concrete model, the pier body is considered to be safe.

5. The rapid construction method of a full rigid frame concrete segmental beam bridge based on machine-beam collaboration as claimed in claim 1, characterized in that: The bridge erection machine includes a truss main body, a plurality of legs are arranged at intervals along the longitudinal direction of the bridge at the bottom of the truss main body, and slide rail frames are symmetrically arranged along the longitudinal direction of the bridge on both sides of the legs located at the center of the segment beam area to be constructed of the truss main body, and a pair of support beams are slidably connected to the slide rail frames on each side, and the support beams extend along the transverse direction of the bridge, and a row of tensioning holes are arranged at intervals along the transverse direction of the bridge on the support beams, and the top of the fine-rolled threaded steel bar passes through a tensioning hole upward, and then a fastening nut is sequentially sleeved to connect the tensioning facility, and the lower end of the fine-rolled threaded steel bar is connected with a connecting piece for connecting with the segment beam. The top of the segment beam is anchored and connected. A cylindrical hole is provided at one end between the two ends on the same side of a pair of support beams. A pin is connected to the cylindrical hole at the other end. A plug hole is provided on the pin along the transverse direction of the bridge. Multiple plug holes are arranged axially on the pin. A positioning card is inserted into one of the plug holes to fix the spacing between the pair of support beams. A distance measuring sensor is provided between the pair of support beams. A distance measuring sensor is provided downward at the bottom of the support beam. A distance measuring sensor is provided at the bottom of the support beam toward the bridge erection machine leg corresponding to the T-structure currently under construction. A remote control terminal is set up to communicate with all distance measuring sensors, and the period from the beginning of hoisting of the correction segment to the removal of the high-quality rolled threaded steel of the previous T-structure is used as a monitoring construction time period to monitor the data changes of all distance measuring sensors. During the same monitoring construction time period of the next T-structure, the real-time data obtained by the distance measuring sensors at the corresponding positions are compared to guide the position setting of the high-quality rolled threaded steel corresponding to the next T-structure, so as to move the support beam along the slide rail frame, determine the spacing between a pair of support beams, select the tensioning holes, and locate the installation position of the high-quality rolled threaded steel.

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