Lightweight main cable saddle and mounting method thereof

Abstract

The invention relates to a lightweight main cable saddle and a mounting method thereof, and particularly discloses a lightweight main cable saddle which adopts a three-section design of a forge welding structure, and is connected by adopting high-strength bolts after being hoisted in sections on a construction site; and the junction surface of the front section and the middle section and the junction surface of the middle section and the rear section form an inverted trapezoidal wedge opening, so that each section is uniformly stressed when the main cable saddle bears the blocking acting force of a main cable. And in the hoisting process of the main cable saddle, the rear section, the middle section and the front section are sequentially lifted to the main tower, but after the middle section is lowered, the middle section is firstly supported at a higher height, after the front section is lifted and lowered, a proper wedge opening is formed in the combination surface of the rear section and the front section, the middle section is lowered in place, so that the rear section, the middle section and the front section are tightly attached, and then the rear section, the middle section and the front section are connected through high-strength bolts.

Description

Technical Field

[0001] The invention relates to a suspension bridge saddle structure and a lifting and hoisting installation method thereof, and in particular to a lightweight main saddle and an installation method relying on a disclosed lifting device to lift and install the main saddle. Background Art

[0002] The saddle is an important load-bearing component of a suspension bridge. The larger the span of the saddle, the heavier the weight of the saddle. In a 2,000-meter-class suspension bridge, the weight of the main saddle is basically in the 200-ton level, which poses a huge challenge to the transportation and installation of the saddle, especially in mountainous areas, where this problem is more obvious.

[0003] Castings have a wide range of applications and are not limited by the size, thickness, and complexity of shapes of castings, and their production methods are flexible. At present, cable saddles mainly adopt a fully cast or cast-welded structure design. The cast-welded combination is that the saddle head used for limiting and directly bearing the main cable is formed by a casting process, while the saddle head and the saddle body are combined by a welding process. However, the casting industry consumes a lot of energy and causes great pollution; therefore, casting companies with small scale, backward technology, serious pollution, and poor working conditions have been eliminated in recent years, resulting in a shortage of casting resources and a significant extension of the casting period of cast steel year-on-year; this has in turn lengthened the manufacturing cycle of cable saddles, increased capital investment, and increased the manufacturing cost of cable saddles.

[0004] In addition, steel castings have the characteristics of uneven organization, coarse internal grains and non-dense organization, which leads to low mechanical properties. As the span of bridges increases, oversized cable saddle structures are common. The tensile strength grade of the main cable wire has increased from 1670MPa to more than 2000MPa. As the strength of the main cable increases, the pressure on the saddle groove per unit cross section increases, and the contact stress at the bottom of the groove increases. Through the sliding test of cast steel cable saddles and high-strength steel wire strands, it was found that after the strands slipped, very obvious and dense main cable wire tensile indentations were formed on the side walls of the saddle groove and the bottom of the strand groove. The indentation depth was mostly between 0.5 and 1mm, and there were even cases where the indentation depth exceeded 1mm. Therefore, the molding quality and mechanical properties of the oversized casting saddle head face real challenges, and even the strength of its material is no longer compatible with the high-strength main cable wire. Summary of the invention

[0005] The purpose of the present invention is to provide a lightweight main cable saddle to solve the problem that the cable saddle is heavy and difficult to transport and install in mountainous areas.

[0006] Solution 1: A lightweight main cable saddle is composed of a front section, a middle section and a rear section connected by high-strength bolts. After the cable saddle is assembled, the joint surface of the front section and the middle section and the joint surface of the middle section and the rear section form an inverted trapezoidal wedge, and the inclination directions of the two joint surfaces relative to the horizontal plane are opposite; The front section, middle section and rear section all include a pommel and a saddle base. The pommel is formed by welding a bottom steel forging and a saddle groove side wall steel plate. The saddle base is formed by welding steel plates. The steel plates that make up the saddle base include a main rib plate, a transverse rib plate and a bottom plate.

[0007] The beneficial effects of scheme 1 are: (1) The main saddle is composed of three sections. After being lifted onto the main tower, they are connected to form a whole by high-strength bolts. This allows the saddle to be transported in sections from the factory to the construction site based on components, thereby reducing transportation costs. It is especially suitable for transportation in mountainous areas. Mountainous areas are affected by the terrain, with large bends and unstable foundations. Large transportation equipment is difficult to use and has high operating costs. After segmentation, small transportation equipment suitable for mountainous areas can be used to reduce transportation difficulties.

[0008] (2) The main cable saddle in this scheme adopts a forging and welding structure design, while the structural design of the traditional cable saddle is mainly based on the full casting structure and cast welding structure formed by the casting process; due to the internal organizational defects, the mechanical properties of the cast structure are far inferior to the forged structure, which is mainly reflected in poor strength and toughness; and as the span of the suspension bridge continues to increase, the steel wire of the main steel cable, which plays a major load-bearing role in the suspension bridge, has been significantly increased through technical optimization. The strength of the main cable saddle and the steel wire that still uses the casting process is no longer matched. In this scheme, the bottom of the saddle groove uses forged steel parts, which can significantly improve its strength, and there are more forging materials to choose from, which is more conducive to matching the strength of the steel rope with the strength of the cable saddle; and the increase in the selection of forging materials makes it possible to further match the strength of the cable saddle with the further development and improvement of the steel rope technology and strength in the later stage. In addition, due to the high strength of the forged parts, the precision of the forged billet is also higher than that of the cast billet, and the forged parts use less material, which is beneficial to reducing the weight of the cable saddle.

[0009] (3) Since the bottom of the saddle groove is in direct contact with the main steel cable and plays a load-bearing role, the main saddle is made of steel plates except for the bottom of the saddle groove, which is made of forged steel. This not only reflects the design principle of "using good steel on the blade", but also achieves the purpose of reducing costs and improving manufacturing efficiency.

[0010] (4) Compared with the casting industry, the forging industry has fewer industry restrictions and has more sufficient production capacity at the current stage. This makes the forging and welding combined saddle design have a shorter production cycle, which is conducive to shortening the bridge construction cycle.

[0011] (5) The forces exerted by the main cable on the front, middle and rear sections of the saddle groove are different. The forging mainly bears the downward pressure, while the front and rear sections bear the horizontal force while bearing the downward pressure. The three-section force is more conducive to the tight fit of the main saddle as a whole, and is conducive to distributing the main cable pressure to the saddle base, based on the opposite horizontal forces on the front and rear sections and the downward pressure on the middle section. Secondly, if the saddle adopts a two-section design, the front and rear sections of the main saddle will inevitably be disconnected from the middle, and the middle part of the saddle groove is the main load-bearing and force-decomposition part. In addition, the bottom of the saddle groove is made of forged steel, which has high strength. If there is an error in the middle joint surface to form a step surface, it will cause the steel wire to be stressed, which will have an adverse effect on the main cable wire.

[0012] Furthermore, the bottom forged steel part is forged by using 30CrMo forged steel, and the steel plates used for the saddle groove side walls and the saddle body base are Q420qE steel plates.

[0013] In terms of material selection, in the cast-weld saddle structure, in order to ensure good weldability with the saddle body steel plate, the cast saddle head generally chooses weldable cast steel; and the highest material strength grade of weldable cast steel is ZG340-550H, and its yield strength is not less than 340MPa. The main saddle at this strength is seriously mismatched with the high-strength cast steel wire. And there are only four types of casting materials that meet the requirements of the saddle and meet the standards: ZG230-450H, ZG270-480H, ZG300-500H, and ZG340-550H. After adopting the forging process, there are as many as 75 types of selectable materials that meet the requirements, including 15 carbon steel forgings and 60 alloy steel forgings. This provides more possibilities for designing and manufacturing high-strength and high-performance saddles.

[0014] Based on the current matching demand of increasing the tensile strength of the main cable steel wire to 2000MPa, based on the accumulated experience of engineers and the comparison of relevant experimental structure analysis, 30CrMo forged steel is the first choice for the bottom forged steel parts; based on the weldability of the steel plate and the forged steel parts, Q420qE grade steel plate is selected.

[0015] Furthermore, the angle between the joint surface and the vertical plane is 5-10°. If the angle is too large, it will not be conducive to evenly distributing the mass in the three-section structure, thus failing to achieve the purpose of facilitating transportation; secondly, it will also worsen the stress condition between the joint surfaces of the three-section structure, and will not be conducive to the saddle decomposing the force of the main cable on the saddle.

[0016] Solution 2: A method for installing a lightweight main cable saddle, used to install the lightweight main cable saddle as described in Solution 1, comprising the following steps: Step (1): Install the hoisting equipment on the top of the main tower; Step (2): Use hoisting equipment to lift and install the grid and reaction frame, and pour concrete; after the poured concrete reaches the construction conditions, lift and install the bearing plate; Step (3): lifting the main saddle in sections; (3-1): First, lift the rear section of the main saddle to the rear of the carrier plate, leaving space for the installation of the middle section and the front section; (3-2): Then lift the middle section so that the joint surface of the middle section contacts the rear section, and place a lifting frame under the middle section to support the bottom of the middle section at a higher position relative to the bottom of the rear section; (3-3): Finally, lift the front section so that the joint surface of the front section and the middle section are in contact, and then lower the front section onto the support plate; (3-4): Use lifting equipment to suspend the middle section to bear the load, remove the lifting frame under the middle section and lower the middle section to the bearing plate, adjust the positions of the front section, middle section and rear section, and use high-strength bolts to connect the front section, middle section and rear section; Step (4): Use the reaction frame to push the main cable saddle to adjust its position.

[0017] The beneficial effects of Option 2 are: (1) One of the main differences between the installation method disclosed in this scheme and the traditional cable saddle installation method is that the main cable saddle is lifted in sections. That is, in the traditional installation method, the fully cast or integrated cast-welded cable saddle needs to be lifted directly to the top of the main tower in one step. Due to its large mass, the lifting difficulty is also very large. The segmented lifting of this scheme reduces the mass of each lift, which reduces the difficulty of lifting. Especially when building bridges between mountains, it is extremely difficult to transport construction equipment, especially large equipment. If the main cable saddle is to be lifted to the main tower as a whole at one time, a large hoisting machine and other lifting equipment must be installed on the top of the main tower. The transportation and installation of the lifting equipment will incur a large cost and installation period. However, the mass of each lift in this scheme is less, so a smaller hoisting machine can be used, which will help reduce the investment cost of hoisting equipment and shorten the installation period.

[0018] (2) After the main cable saddle is lifted to the top of the main tower, it is necessary to use several high-strength bolts to connect them. High-strength bolts are usually tightened one by one, so it is difficult to make the joint surfaces of each segment fit tightly by tightening the bolts; therefore, it is necessary to make the joint surfaces fit tightly before tightening the bolts. However, the two joint surfaces form an inverted trapezoidal wedge, and after the cable saddle sections are lifted to the top of the main tower, in order to facilitate lateral movement, the cable saddle sections have a certain height from the ground from the supporting plate. In addition, it is difficult to control the lateral and vertical movements simultaneously during the movement. This makes it necessary to lower the cable saddle sections in the order of lifting the rear section, the middle section, and the front section, which will result in a large gap between the joint surfaces, especially between the joint surfaces of the middle section and the front section. This results in multiple pushes before bolt connection to make the joint surfaces fit tightly. In the present scheme, the middle section is first supported at a higher position, and after the front and rear sections are lowered, the middle end is lowered. Moreover, before the middle section is positioned by the jacking frame, the joint surfaces of the middle section and the rear section are in contact, and before the front section is lowered, the joint surfaces of the front and middle sections are in contact. Therefore, the width of the wedge formed by the joint surfaces of the rear and front sections after they are laid on the ground is slightly smaller than the width of the middle section. After the middle section is lowered, the front and rear sections slide slightly, and the gravity of the middle section opens the wedge, so that the joint surfaces fit tightly.

[0019] Furthermore, a polytetrafluoroethylene board is laid on the support plate, which has low friction and is convenient for pushing the cable saddle.

[0020] Furthermore, the lifting height of the middle section is controlled at 10-30 cm. If the lifting height of the middle section is too high, it will be inconvenient to position the middle section; secondly, as the lifting height increases, the installation height of the lifting equipment should also increase accordingly, which will increase the installation cost of the lifting equipment.

[0021] Furthermore, the hoisting equipment includes a gantry installed on the top of the main tower. The gantry adopts a truss structure. A cable saddle introduction port is reserved on the gantry toward the middle span side (i.e., the front side of the gantry). Parallel slide rails are set on the top of the left and right sides of the gantry along the direction of the bridge. A traction system is installed on the gantry toward the side span side (i.e., the end of the gantry). The traction system is a winch. A sliding platform is installed on the slide rail, and the sliding platform is slidably connected to the slide rail. A load-bearing shaft is fixed on the front side of the sliding platform, and a rotatable drum is arranged outside the load-bearing shaft. The cable of the traction system is wound around the drum. A cavity is provided in the bearing shaft, in which a control assembly is installed, a plurality of first positioning holes are provided on the side wall of the slide rail, and a plurality of second positioning holes are evenly distributed on the inner wall of the rotating drum along the circumferential direction; the control assembly includes a first positioning rod that can slide along the axial direction of the cavity, and the first positioning rod enters the first positioning hole to position the sliding platform; the control assembly also includes a positioning column that penetrates the side wall of the bearing shaft and can slide radially along the bearing shaft, and the positioning column enters the second positioning hole to position the rotating drum; A tension spring I is sleeved on the first positioning rod so that the first positioning rod is subjected to a force that pushes it toward the first positioning hole. A piston I is provided at the end of the first positioning rod that is away from the first positioning hole. The two sides of the piston I are respectively the first oil chamber where the first positioning rod is located and the second oil chamber where the positioning column is located. When the first oil chamber is pressurized, the piston I moves toward the second oil chamber, the first positioning rod is disengaged from the first positioning hole, and the second oil chamber pushes the positioning column into the second positioning hole, thereby switching the positioning state of the sliding platform to the rotating drum positioning state. A tension spring II is provided below the positioning column so that the positioning column is subjected to a force that pulls it away from the second positioning hole. When the pressure of the first oil chamber is relieved, the tension spring I pushes the first positioning rod toward the first positioning hole, the pressure of the second oil chamber is reduced, and the tension spring II pulls the positioning column out of the second positioning hole, thereby switching the rotating drum positioning state to the sliding platform positioning state.

[0022] In this preferred embodiment, the structure of the lifting equipment is optimized.

[0023] First, the structure of the hoisting equipment is optimized. In the process of lifting the saddle, the vertical and horizontal movements of the saddle are driven by the same traction system (such as a hoist); in the existing hoisting equipment, the lateral movement and vertical movement need to adopt independent driving mechanisms. Therefore, the hoisting equipment of this scheme is more streamlined in structure and more convenient to install. The specific hoisting process is that the sliding platform is positioned at the front end of the gantry through the cooperation of the first positioning rod and the first positioning hole. At this time, the drum is in a rotatable state. After the saddle is hung, the traction system reels the cable, and the friction between the cable and the drum causes the drum to rotate, so that the saddle can be lifted; when the saddle is lifted to a certain height, the first oil chamber is pressurized, and the pressure in the second oil chamber will also increase. In conjunction with the rotation of the drum, when the positioning column is opposite to the second positioning hole, the positioning column will enter the second positioning hole, and the drum will no longer be able to rotate. At this time, the first positioning rod will also be separated from the first positioning hole, and the traction force of the traction system will be converted into pulling the sliding platform to slide, realizing lateral movement. That is, the large power system of this solution only needs one set of winches. The control component is an extremely weak power device compared to the winch. The two are linked to achieve weak control of strong. By using fewer large devices and more small devices, the installability of the lifting equipment is improved. The lateral movement and vertical movement drive systems are independent of each other, which increases the difficulty of installation.

[0024] Secondly, it has more advantages in extending the controllability of the lifting equipment. The control component set in the cavity of the load-bearing shaft only plays a control role in switching the state, so it does not require excessive driving force and large power equipment; secondly, due to the incompressibility of hydraulic oil, the positioning state of the sliding platform and the positioning state of the drum are in a mutually restrained state, that is, when the sliding platform is in the positioning state, the drum will be in a rotatable state, and when the drum is in the positioning state, the sliding platform is in a slidable state; therefore, after the traction system is started, the state can be switched only by the control component. In the original lifting equipment, vertical movement and lateral movement are driven by different devices and need to be controlled independently, so the factors affecting its controllability have increased. In this scheme, the state can be switched through a single control, and the factors affecting its controllability are greatly reduced. With the development of intelligent control, automatic control is an inevitable trend of development. Since the lifting weight of the saddle is extremely large, its safety consideration must be placed in the first place. If there are many factors affecting its controllability when introducing automatic control, its safety risk will increase. Therefore, by reducing the factors affecting controllability, more favorable conditions are provided for the introduction of automatic control.

[0025] Furthermore, the slide rail is in an inclined state with a higher end, and the inclination angle is 5-8 degrees. A traction system is set at the end of the gantry, which can switch the saddle in three directions: rising, falling, and moving backward; when the track is in a horizontal state, the sliding platform needs to move forward, and a driving structure needs to be set; and by setting the slide rail at an angle, the sliding platform can be moved by its own gravity.

[0026] Furthermore, a buffer chamber is provided on the side of the second oil chamber away from the first oil chamber, a piston II and a compression spring abutting against the piston II are provided in the buffer chamber, a positioning screw is provided in the second oil chamber, and the compression spring presses the piston II toward the positioning screw; a positioning seat is provided below the positioning column, the positioning seat is threadedly connected to the side wall of the load-bearing shaft, a positioning surface is provided on the positioning seat, and the positioning surface forms a stepped surface with the outer side surface of the positioning column; the piston I contacts the outer side surface of the positioning column, the first positioning rod is still matched with the first positioning hole, the piston I contacts the positioning surface of the positioning seat, and the first positioning rod is disengaged from the first positioning hole.

[0027] Since hydraulic oil is incompressible, by setting a buffer chamber, during the change from the first positioning rod and the first positioning hole being in full cooperation to the piston I contacting the outer side of the positioning column, the first positioning rod and the first positioning hole are still in cooperation, and during this process, when the positioning column and the second positioning hole are not yet aligned, the buffer chamber provides conditions for the piston I to move to the outer side of the positioning column; if the piston I continues to move forward, the positioning column needs to be aligned with the second positioning hole, and the positioning column enters the second positioning hole, and the piston I can contact the positioning surface of the positioning seat. That is, by controlling the piston I to move in stages, the impact force on the positioning surface of the piston and the positioning seat can be reduced. On the contrary, when the pressure of the first oil chamber is removed, the positioning column and the second positioning hole are still in cooperation; after the first positioning hole is aligned with the first positioning column, the first positioning column enters the first positioning hole, and the positioning column can be separated from the second positioning hole.

[0028] Since there is a risk of hydraulic oil leakage, once the hydraulic oil in the second oil chamber leaks, the rotating drum and the sliding platform may be in an unlocked state, which poses a safety risk; in this solution, the piston I cooperates with the outer side of the positioning column and the positioning surface of the positioning seat to ensure that the positioning state of the sliding platform and the positioning state of the rotating drum are in a mutually restrained state.

[0029] Furthermore, the buffer chamber maintains a normal pressure state, thereby facilitating the resetting of the piston II in the buffer chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a three-dimensional diagram of the lightweight main saddle; Figure 2 This is a diagram showing the height of the middle section of the lightweight main cable saddle when it is installed in three sections; Figure 3 It is a schematic diagram of the lifting equipment; Figure 4 A transverse cross-sectional view of the sliding rail and the slider in sliding cooperation; Figure 5 A longitudinal cross-sectional view of the sliding rail and the slider in sliding cooperation; Figure 6 It is a state diagram of the sliding platform in the lifting state; Figure 7 for Figure 4 A magnified view of part A; Figure 8 for Figure 4 A magnified view of part B; Fig. 9 It is a state diagram of the sliding platform during the switching process from the lifting state to the lateral movement state; Fig.10 It is the state diagram of the sliding platform in the lateral movement state; Fig.11 This is the finite element extrusion analysis diagram of ZG270-480H casting; Fig.12 This is the finite element extrusion analysis diagram of ZG300-500H casting; Fig.13 This is the finite element extrusion analysis diagram of 30CrMo forged steel.

[0031] The figure marks in the drawings of the specification include: forged steel part 1, saddle groove side wall steel plate 2, main rib plate 3, cross rib plate 4, bottom plate 5, lifting ring 6, front section 11, middle section 12, rear section 13, lifting frame 14, door frame 21, traction system 22, sliding platform 23, slide rail 24, roller shaft 241, first positioning rod 31, first positioning hole 311, piston I32, positioning column 33, second positioning hole 331, positioning seat 34, sealing cover 35, piston II36, buffer chamber 37, second oil chamber 38, first oil chamber 39, positioning screw 41, second positioning stud 42, oil inlet nozzle 43, collar 44, mounting plate 231, load-bearing shaft 232, rotating drum 233, tension spring I391, tension spring II341. DETAILED DESCRIPTION

[0032] The following is further described in detail through specific implementation methods: As attached Figure 1 , Attachment Figure 2 As shown, the lightweight main cable saddle is composed of a front section 11, a middle section 12 and a rear section 13. Each section of the cable saddle includes a saddle head and a saddle body base. The saddle head in this embodiment is welded by a 30CrMo forged steel piece 1 at the bottom and a saddle groove side wall steel plate 2 with a grade of Q420qE. The saddle body base is welded by a bottom plate 5, a main rib plate 3 and a transverse rib plate 4. The steel plates used are all of the grade of Q420qE. The main rib plate 3 and the transverse rib plate 4 are used to support the saddle head. The main rib plate 3 supports the saddle head from below along the saddle groove direction, and the transverse rib plate 4 supports the saddle head from the side. After the saddle head and the saddle body base are welded separately, the saddle head and the saddle body base are combined and welded to form the front section 11, the middle section 12 and the rear section 13 of the main cable saddle; the above stages are all processed in the factory, while the front section 11, the middle section 12 and the rear section 13 are assembled at the construction site and connected with high-strength bolts.

[0033] Since the main cable saddle of this scheme adopts a three-section structure, in order to make each section of the main cable saddle evenly share the main cable pressure and make each section of the main cable saddle closely contact during the pressure bearing process, the connection of the front section 11, the middle section 12 and the rear section 13 is designed as follows: the contact surface between two adjacent sections of the cable saddle is defined as the bonding surface, then the bonding surface between the front section 11 and the middle section 12 and the bonding surface between the middle section 12 and the rear section 13 are symmetrically arranged along the vertical plane, and after the three sections are connected, the two bonding surfaces form an inverted trapezoidal structure. In this embodiment, the angle between the two bonding surfaces and the vertical plane is set to 8°.

[0034] In order to facilitate the hoisting of the main saddle, two lifting rings 6 are respectively welded on the saddle groove side wall steel plates 2 on both sides of the front section 11, the middle section 12 and the rear section 13.

[0035] In terms of material selection, especially the material selection of the forged steel parts 1 directly bearing the pressure of the steel cable is crucial. In the material selection experiment, based on the previous work experience and aiming at the preset yield strength of the forged steel material not less than 390 MPa, the engineer carried out a comparative study on the strength index of the forged steel materials required for the forged-welded combined saddle for three materials, namely 30CrMo, 20CrMnMo and 20CrNiMo. The research results show that while the strength index of the forged steel 30CrMo material meets the requirements, the slope is gentler, and the material has relatively consistent mechanical properties from the core to the surface, which can be used as the preferred forged steel material for the saddle. At the same time, the impact resistance of the 30CrMo material under different low-temperature conditions was further studied, and this material has relatively excellent low-temperature toughness. In terms of welding performance, the MT detection of the welding evaluation test plate meets the requirements of Grade 1 in GB / T 26952-2011, and the UT detection meets the requirements of Grade I in NB / T47013.3-2015. The performance of the structural welds all meets the requirements of the high-performance forged-welded combined saddle, forming good quality and efficiency.

[0036] By using steel components cast from different types of raw materials and 30CrMo forged steel for finite element analysis and the extrusion test of the cable strands and the saddle groove, as shown in the appendix Figure 11-13 as follows: (1) The order of the indentation depth is: 30CrMo < ZG300-500H < ZG270-480H, and the finite element analysis results of the indentation depth of the forging 30CrMo are relatively more uniform.

[0037] (2) The order of the number of plastic deformation units entered is 30CrMo < ZG300-500H < ZG270-480H.

[0038] (3) Among the three research materials, the forged steel 30CrMo material has better anti-extrusion deformation ability, higher surface hardness, and the cost is also the steel to be considered first. It can be used as the forged steel material for the bottom bearing part of the saddle groove of the forged-welded combined saddle.

[0039] Combined with the finite element analysis and the extrusion test, for the structural reasonable form and performance analysis of the forged-welded combined saddle, the forged-welded combined lightweight saddle uses high-strength forged steel (30CrMo) + Q420qE to replace the cast-welded saddle (ZG270-480H + Q345R). The overall strength of the structure is increased by 44%, and at the same time the weight of the main saddle is reduced by 26% respectively, achieving the purpose of high strength and lightweight of the saddle structure. The use of Q420qE grade forged steel has higher strength, can effectively prevent the erosion and compression deformation of the main cable on the saddle, and the quality has been greatly improved.

[0040] The above-mentioned method for installing the lightweight main cable saddle comprises the following steps: Step (1): Install the hoisting equipment on the top of the main tower; Step (2): using hoisting equipment to lift and install the grid and reaction frame, and pouring concrete; after the poured concrete reaches the construction conditions, lifting and installing the support plate, and laying the PTFE plate on the support plate; Step (3): lifting the main saddle in sections; (3-1): First, lift the rear section 13 of the main saddle to the rear of the carrier plate, leaving space for the installation of the middle section 12 and the front section 11; (3-2): Then lift the middle section 12 so that the joint surface of the middle section 12 and the rear section 13 are in contact, and place a lifting frame 14 under the middle section 12 to support the bottom of the middle section 12 at a higher position than the bottom of the rear section 13; as shown in the attached figure Figure 2 As shown, the lifting height of the middle section 12 is controlled at about 15 cm; (3-3): Finally, the front section 11 is lifted so that the joint surface of the front section 11 and the middle section 12 are in contact, and then the front section 11 is lowered onto the support plate; (3-4): Use the lifting equipment to suspend the middle section 12 to bear the load, remove the lifting frame 14 under the middle section 12 and lower the middle section 12 to the bearing plate, adjust the positions of the front section 11, the middle section 12 and the rear section 13, and then use high-strength bolts to connect the front section 11, the middle section 12 and the rear section 13; In step (3), when each section of the main saddle is lifted to a level higher than the mounting grid and is moved laterally to enter above the support plate, the height difference between its bottom surface and the support plate in the vertical direction is controlled to be about 5 cm.

[0041] Step (4): Use the reaction frame to push the main cable saddle to adjust the position and fix the main cable saddle.

[0042] like Figure 3 As shown, in this embodiment, the hoisting equipment mentioned in step (1) includes a gantry 21 installed on the top of the main tower. The gantry 21 adopts a truss structure. A saddle inlet is reserved on the gantry 21 facing the mid-span side. Slide rails 24 are arranged parallel to the left and right sides of the top of the gantry 21 along the direction of the bridge. A traction system 22 is installed on the top of the gantry 21 facing the side span. The traction system 22 in this embodiment is a winch. The slide rail 24 is inclined at an angle of 8°, with the saddle inlet end being the lower end. The slide rail 24 is slidably connected to the sliding platform 23. As shown in the attached figure, Figure 4 , 5As shown, sliders are fixed at both ends of the sliding platform 23, and the sliding platform forms a sliding fit with the slide rail 24 through the sliders, and a plurality of rollers 241 are provided between the sliders and the slide rail, and a plurality of semicircular grooves are provided on the bottom surface of the slider, and the rollers 241 are embedded in the semicircular grooves; therefore, in the case of being not disturbed by other external forces, the sliding platform 23 will slide toward one end of the saddle inlet under its own gravity.

[0043] Two mounting plates 231 are welded to the bottom surface of the sliding platform 23, and both ends of the load-bearing shaft 232 pass through the mounting plates 231 and are welded to the mounting plates 231, so that the load-bearing shaft 232 and the sliding platform 23 are in a fixed state; the load-bearing shaft 232 is located between the opposite side walls of the two sides of the slide rails 24, and the end face of the load-bearing shaft 232 is in contact with the side of the slide rail 24 or there is a very small gap, so that the load-bearing shaft 232 can slide relative to the slide rail 24. A rotatable drum 233 is disposed outside the bearing shaft 232, and the cable of the traction system 22 is wound around the drum 233. When the sliding platform 23 is fixed on the slide rail 24, the friction between the cable and the drum 233 drives the drum 233 to rotate, so that the saddle can be lifted; and when the drum 233 is fixed to the bearing shaft 232, and the sliding platform 23 and the slide rail 24 are in a sliding state, the traction system 22 can drive the sliding platform 23 to slide on the slide rail 24 through the friction between the cable and the drum 233. Here, the state in which the cable can be raised and lowered when the drum 233 rotates is defined as the lifting state, and the state in which the sliding platform 23 moves laterally is positioned as the transverse movement state. In order to realize the switching between the lifting state and the transverse movement state, the control component is introduced below.

[0044] As attached Figure 6 , 10 As shown, the bearing shaft 232 has a cavity inside, in which a control assembly is installed. A plurality of first positioning holes 311 are provided on the side wall of the slide rail 24, and four second positioning holes 331 are evenly distributed along the circumferential direction on the inner wall of the rotating drum 233. The control assembly includes a first positioning rod 31 that can slide along the axial direction of the cavity, and the first positioning rod 31 enters the first positioning hole 311 to position the sliding platform 23. The first positioning rod 31 cooperates with the first positioning holes 311 at different positions to position the sliding platform 23 at different positions on the slide rail 24. The control assembly also includes a positioning column 33 that passes through the side wall of the bearing shaft 232 and can slide radially along the bearing shaft 232, and the positioning column 33 enters the second positioning hole 331 to position the rotating drum 233. As shown in the attached figure Figure 6 As shown, at this time, the sliding platform 23 is in a lifting state, that is, the first positioning rod 31 is in a matching state with the first positioning hole 311, the sliding platform 23 is in a fixed state relative to the slide rail 24, and the rotating drum 233 is in a rotating state relative to the bearing shaft 232. During the rotation of the rotating drum 233, the second positioning hole 331 is periodically aligned with the positioning column 33, and the attached Figure 6 What is presented is the state that the second positioning hole 331 and the positioning column 33 are not aligned (misaligned). Fig.10 As shown, the sliding platform 23 is in a transverse state at this time, that is, the second positioning hole 331 is aligned with the positioning column 33 and the positioning column 33 enters the second positioning hole 331 , while the first positioning rod 31 is out of the first positioning hole 311 .

[0045] As attached Figure 6 , Attachment Figure 7 As shown, a tension spring 1391 is sleeved on the first positioning rod 31 so that the first positioning rod is pushed toward the first positioning hole 311. A piston 132 is arranged at the right end of the first positioning rod 31. The two sides of the piston 132 are respectively the first oil chamber 39 where the first positioning rod 31 is located and the second oil chamber 38 where the positioning column 33 is located. The side wall of the first oil chamber 39 is provided with two threaded holes, one of which is used to connect the oil inlet nozzle 43 to pressurize the hydraulic oil into the first oil chamber 39, and the other threaded hole is used to thread the second positioning stud 42. The second positioning stud 42 is screwed into the first oil chamber 39 to limit the piston 132 to limit the stroke of the first positioning rod 31. Secondly, as shown in the attached Figure 7 As shown, the tension spring 1391 should be in a tensioned state, and both ends of the tension spring 1391 need to be fixed. Therefore, a collar 44 is welded on the end of the tension spring 1391 facing the piston 132, and a limiting hole is provided on the collar 44. The end of the first positioning rod 31 facing the piston 132 is provided with a threaded hole. The collar 44 can be positioned on the first positioning rod 31 by inserting a stud into the limiting hole and screwing the stud into the threaded hole. Figure 6 As shown, a sealing cover 35 is threadedly connected to the left side of the cavity, the first positioning rod 31 passes through the sealing cover 35 and forms a sealing connection, the other end of the tension spring I391 is welded to the sealing cover 35, or a gasket is provided under the sealing cover 35, the gasket can be tightened by tightening the thread, and the tension spring I391 is welded to the gasket.

[0046] A tension spring II341 is provided below the positioning column 33 to pull the positioning column 33 away from the second positioning hole 331. A positioning seat 34 is provided below the positioning column 33. The positioning seat 34 is threadedly connected to the side wall of the second oil chamber 38. The positioning seat 34 is provided with a blind hole that matches the end of the positioning column 33 to further limit the positioning column 33. Figure 8 As shown, the front end of the positioning column 33 (i.e., the end that matches the second positioning hole 331) and the end form a step shape, and a ring groove is provided on the step surface. One end of the tension spring II341 is inserted into the ring groove to be fixed to the positioning column 33. The fixing method is the same as that of the tension spring I391. The other end of the tension spring II341 is welded to the positioning seat 34. A positioning surface is set on the positioning seat 34. The positioning surface and the outer side surface of the front end of the positioning column 33 are also stepped surfaces; as shown in the attached Fig. 9 As shown, the piston 132 contacts the outer side surface of the front end of the positioning column 33, and the first positioning rod 31 and the first positioning hole 311 are still matched. Fig.10As shown, the piston 132 contacts the positioning surface of the positioning seat 34, and the first positioning rod 31 is disengaged from the first positioning hole 311.

[0047] A buffer chamber 37 is provided at the right end of the second oil chamber 38, a piston II36 and a compression spring abutting against the piston II36 are provided in the buffer chamber 37, a positioning screw 41 is provided in the second oil chamber 38, and the compression spring presses the piston II36 toward the positioning screw 41 to limit the travel of the piston II36 toward the second oil chamber 38. The buffer chamber 37 is connected to the outside and is in a normal pressure state. In this embodiment, the control components are provided at both ends of the load-bearing shaft 232, that is, the control components at both ends are symmetrically provided.

[0048] As attached Figure 6 As shown, when in the lifting state, the first oil chamber 39 is pressurized (the pressurizing device can be a hydraulic pump, which is installed above the sliding platform 23), so that the control component presents the following Fig. 9 In the state shown in the figure, the sliding platform 23 is in the intermediate state of switching from the lifting state to the lateral state. Although the piston I32 moves toward the second oil chamber 38 and contacts the outer side of the front end of the positioning column 33, and the piston II36 moves to the right, so that the pressure of the second oil chamber 38 is also increased, the second positioning hole 331 is not aligned with the positioning column 33; with the continuous application of tension by the cable, the drum 233 rotates, and the control component presents the following Fig.10 In the state shown, the positioning column 33 is aligned with the second positioning hole 331; under the pressure of the second oil chamber 38, the positioning column 33 enters the second positioning hole 331, and under the continuous pressurization of the first oil chamber 39, the piston I32 continues to move forward and contacts the positioning surface of the positioning seat 34, then the first positioning rod 31 disengages from the first positioning hole 311, completing the switching from the lifting state to the lateral displacement state.

[0049] When in the transverse state, the pressure in the first oil chamber 39 is released, and the cable continuously applies tension, so that the first positioning rod 31 will be aligned with one of the first positioning holes 311, and the tension spring I391 will push the first positioning rod 31 toward the first positioning hole 311; and the piston II36 is limited by the positioning screw 41, the pressure in the second oil chamber 38 is reduced, and the tension spring II341 pulls the positioning column 33 out of the second positioning hole 331, completing the switching from the transverse state to the lifting state.

[0050] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. A lightweight main cable saddle, characterized by: The saddle is composed of a front section, a middle section and a rear section connected by high-strength bolts. After the saddle is assembled, the joint surface of the front section and the middle section and the joint surface of the middle section and the rear section form an inverted trapezoidal wedge. The two joint surfaces are inclined in opposite directions relative to the horizontal plane, and the angle between the joint surface and the vertical plane is 5-10°. The front section, middle section and rear section all include a saddle head and a saddle body base. The saddle head is formed by welding the bottom forged steel piece and the saddle groove side wall steel plate. The saddle body base is formed by welding the steel plate. The steel plates constituting the saddle body base include the main rib plate, the transverse rib plate and the bottom plate. The bottom forged steel piece is forged by using 30CrMo forged steel, and the steel plates used for the saddle groove side wall steel plates and the saddle body base are Q420qE steel plates.

2. A method for installing a lightweight main cable saddle, used for installing the lightweight main cable saddle according to claim 1, characterized in that: The steps include: Step (1): Install the hoisting equipment on the top of the main tower; Step (2): Use hoisting equipment to lift and install the grid and reaction frame, and pour concrete; after the poured concrete reaches the construction conditions, lift and install the bearing plate; Step (3): lifting the main saddle in sections; (3-1): First, lift the rear section of the main saddle to the rear of the carrier plate, leaving space for the installation of the middle section and the front section; (3-2): Then lift the middle section so that the joint surface of the middle section contacts the rear section, and place a lifting frame under the middle section to support the bottom of the middle section at a higher position relative to the bottom of the rear section; (3-3): Finally, lift the front section so that the joint surface of the front section and the middle section are in contact, and then lower the front section onto the support plate; (3-4): Use lifting equipment to suspend the middle section to bear the load, remove the lifting frame under the middle section and lower the middle section to the bearing plate, adjust the positions of the front section, middle section and rear section, and use high-strength bolts to connect the front section, middle section and rear section; Step (4): Use the reaction frame to push the main cable saddle to adjust its position.

3. The method for installing a lightweight main cable saddle according to claim 2, characterized in that: A polytetrafluoroethylene plate is laid on the support plate.

4. The method for installing a lightweight main cable saddle according to claim 3, characterized in that: The lifting height of the middle section is controlled at 10-30cm.

5. The method for installing a lightweight main cable saddle according to claim 4, characterized in that: The hoisting equipment includes a gantry installed on the top of the main tower. The gantry adopts a truss structure. A cable saddle introduction port is reserved on the gantry toward the middle span. Parallel slide rails are set on the top of the left and right sides of the gantry along the direction of the bridge. A traction system is installed on the gantry toward the side span. The traction system is a winch. A sliding platform is installed on the slide rail, and the sliding platform is slidably connected to the slide rail. A load-bearing shaft is fixed on the front side of the sliding platform, and a rotatable drum is arranged outside the load-bearing shaft. The cable of the traction system is wound around the drum. A cavity is provided in the bearing shaft, in which a control assembly is installed, a plurality of first positioning holes are provided on the side wall of the slide rail, and a plurality of second positioning holes are evenly distributed on the inner wall of the rotating drum along the circumferential direction; the control assembly includes a first positioning rod that can slide along the axial direction of the cavity, and the first positioning rod enters the first positioning hole to position the sliding platform; the control assembly also includes a positioning column that penetrates the side wall of the bearing shaft and can slide radially along the bearing shaft, and the positioning column enters the second positioning hole to position the rotating drum; A tension spring I is sleeved on the first positioning rod so that the first positioning rod is pushed toward the first positioning hole. A piston I is arranged at one end of the first positioning rod away from the first positioning hole. The two sides of the piston I are respectively the first oil chamber where the first positioning rod is located and the second oil chamber where the positioning column is located. When the first oil chamber is pressurized, the piston I moves toward the second oil chamber, the first positioning rod is separated from the first positioning hole, and the second oil chamber pushes the positioning column into the second positioning hole, thereby switching the positioning state of the sliding platform to the rotating drum positioning state. A tension spring II is arranged under the positioning column so that the positioning column is subjected to a force that pulls it away from the second positioning hole, thereby relieving the pressure in the first oil chamber. The tension spring I pushes the first positioning rod toward the first positioning hole, and the pressure in the second oil chamber is reduced. The tension spring II pulls the positioning column out of the second positioning hole, thereby switching the drum positioning state to the sliding platform positioning state.

6. The method for installing a lightweight main cable saddle according to claim 5, characterized in that: The slide rail is in an inclined state with a higher end, and the inclination angle is 5-8°.

7. The method for installing a lightweight main cable saddle according to claim 6, characterized in that: A buffer chamber is provided on the side of the second oil chamber away from the first oil chamber, a piston II and a compression spring abutting against the piston II are provided in the buffer chamber, a positioning screw is provided in the second oil chamber, and the compression spring presses the piston II toward the positioning screw; a positioning seat is provided below the positioning column, the positioning seat is threadedly connected to the side wall of the load-bearing shaft, a positioning surface is provided on the positioning seat, and the positioning surface forms a stepped surface with the outer side surface of the positioning column; The piston 1 contacts the outer side surface of the positioning column, the first positioning rod is still matched with the first positioning hole, the piston 1 contacts the positioning surface of the positioning seat, and the first positioning rod is disengaged from the first positioning hole.

8. The method for installing a lightweight main cable saddle according to claim 7, characterized in that: The buffer chamber is maintained at normal pressure.

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