Method for repairing camber of girder of double-girder crane

Abstract

The invention relates to a double-girder crane girder camber repairing method which comprises the following steps: acquiring crane data to determine mounting points of a supporting seat and an anti-shake bracket; pull rods are arranged at the bottoms of the girders and the end beams and are mounted at the bottoms of the two beams based on supporting seats and anti-shake brackets; meanwhile, the two beam pull rods are pre-tightened till the upper camber of the two beams reaches the upper camber reserved deformation value; determining a heating zone, calculating a target heating zone, and performing flame shaping on the crossbeam according to a target heating sequence; and removing the pre-tightening force of the pull rod after complete cooling, judging whether the girder meets a required camber value, and fastening the pull rod after the girder meets the required camber value. Pull rods are arranged at the bottoms of the double beams, uniform pre-tightening force is provided for the double beams, high-temperature shaping is conducted to achieve girder camber repairing, a pre-stress method and a flame straightening method are combined, the girder is evenly stressed in the process, the good repairing effect can be achieved, the effect is kept stable for a long time, the repairing camber curve is smooth, precision is high, and the repairing efficiency is high. Construction is easy and convenient, time is short, the reinforcing effect is remarkable, and the girder is not damaged.

Description

Technical Field

[0001] The present application relates to the field of crane technology, and in particular to a method for repairing the camber of a double-beam crane girder. Background Art

[0002] Double-beam bridge cranes are mainly composed of a bridge, a trolley running mechanism, a trolley, electrical equipment, etc. They are divided into multiple working levels according to the frequency of use. Double-beam bridge cranes in smelting enterprises are used for lifting raw materials. After long-term use, it was measured that the arch of the bridge was sinking, which did not meet the specifications, and there was a safety hazard of the beam breaking downward.

[0003] At present, the cold repair method is often used to repair the arch of the beam. Specifically, the beam is bent by applying eccentric tension using the prestressed reinforcement and the beam is strengthened by the increased stress. Due to the large size of the beam and the internal distribution of ribs, this method is difficult to implement. At the same time, the prestressed reinforcement material cannot maintain its shape and strength for a long time. Each reinforcement is unevenly stressed and the prestressing cannot be aligned with the shear line of the deviated beam. After the repair, the additional prestressing force of the beam is uneven, and the final repair effect is not ideal. Summary of the invention

[0004] In order to solve or partially solve the problems existing in the related art, the present application provides a method for repairing the camber of a double-beam crane beam, which combines the prestressing method and the flame correction method to repair the camber of the beam.

[0005] The first aspect of the present application provides a method for repairing the camber of a double-beam crane girder, comprising the following steps:

[0006] Acquire crane data, and determine the installation points of the support base and the anti-vibration bracket based on the crane data, wherein the crane data includes span data, beam camber data, and lateral bending data;

[0007] Tie rods are arranged at the bottom of the main beam and the end beam, the tie rods penetrate the support base and are installed at the bottom of the two beams based on the support base and the anti-vibration bracket;

[0008] Pre-tighten the tie rods of the two beams at the same time, and continue pre-tightening until the camber of the two beams reaches the reserved deformation value of the camber;

[0009] Determine the heating zone based on the beam deflection curve, calculate the target heating zone and flame shape the beam according to the target heating sequence;

[0010] After complete cooling, release the pre-tightening force of the tie rod and determine whether the beam meets the required camber value. If so, tighten the tie rod.

[0011] The calculation formula of the heating zone is:

[0012] N=8h / (L·θ)-1

[0013] Where h is the chord height corresponding to the upper arch arc; L is the arc length of the upper arch arc; θ is the rotation angle of the cross section caused by linear heating.

[0014] Among them, several positioning lines perpendicular to the lower cover are arranged along the center point of the beam to 3m, 5m and the ends on both sides. The installation points include the center point of the positioning line, the center point of the beam and the intersection of the positioning line and the beam.

[0015] Among them, the heating area is from the center of the beam to the 7m, 4m, and 2m positions on the end beam side. The target heating sequence is to heat the left end first and from the outside to the inside. The heating temperature is 700℃~800℃.

[0016] Among them, the target heating sequence is to heat the lower cover plate first, and then heat the two sides of the belly plate. The lower cover plate is heated by a linear heating method, the belly plate is heated by a point heating method, and the junction of the lower cover plate and the belly plate is heated by a triangle heating method.

[0017] Among them, the pull rod is tightened by a torque wrench, and the torque range is controlled in the range of 2300 to 3000 N·m.

[0018] The technical solution provided by this application may have the following beneficial effects:

[0019] The present application provides a method for repairing the girder arch of a double-girder crane. By laying tie rods at the bottom of the double beams, uniform pre-tightening force is provided to the double beams and high-temperature shaping is performed to achieve the girder arch repair. The prestressing method and the flame correction method are combined. During the process, the girder is subjected to uniform force, which can achieve a better repair effect, and the effect remains stable for a long time. The repaired arch curve is smooth and high in precision. The construction is simple and short in time. The reinforcement effect is significant without damaging the girder.

[0020] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0022] Figure 1 It is a flowchart of the method shown in the embodiment of the present application;

[0023] Figure 2 is a schematic diagram of the installation point of the method shown in the embodiment of the present application;

[0024] Figure 3 It is a schematic diagram of the heating position of the method shown in the embodiment of the present application. DETAILED DESCRIPTION

[0025] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0026] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0027] In the description of the present application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do 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 should not be understood as a limitation on the present application.

[0028] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] The technical solution of the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0030] like Figure 1 The double-beam crane girder camber repair method shown comprises the following steps:

[0031] S1. Obtain crane data, and determine the installation points of the support seat and the anti-vibration bracket based on the crane data.

[0032] After the safety measures are confirmed, crane data measurements are carried out, including span data, beam camber data and lateral bending data.

[0033] Drive the trolley to the side opposite to the cab and measure the span with a 30-meter measuring tape. When measuring, the tail end of the steel measuring tape (take the integer greater than 16500mm) is fixed with a clamp and placed on the outer end face of the trolley wheel. The head end uses a spring to measure the torque. The torque is controlled at 157N and the reading is taken with the side of a ruler against the inner end face of the wheel.

[0034] The wire pulling method is used to measure the camber and lateral bending of the beam. The wire rack is fixed on both sides of the end beams of the beam. The spring measuring torque is pulled to 157N. A 100mm equal height standard block is supported at the center point of the upper plate surface of the two end beams to measure the camber of the beam (the wire correction value is 3.5mm).

[0035] To measure the horizontal lateral bending of the beam, place the steel wire close to the upper cover of the beam, and take an equal distance from one side of the upper cover on the center line of the two end beams of the upper cover, and tighten the steel wire. Then measure the horizontal distance from the same side of the upper cover at the center of the beam span to the steel wire, and record the data during measurement.

[0036] After the data test, the grab bucket is dismantled and placed in a safe position in the silo foundation pit. The drum steel rope is lowered and removed with the aid of a hemp rope.

[0037] S2. Tie rods are arranged at the bottom of the main beam and the end beam. The tie rods pass through the support seat and are installed at the bottom of the two beams based on the support seat and the anti-vibration bracket.

[0038] Put the pre-welded support seat on the tie rod. 16.5m, use 4 1T x 16m hoists to lift the tie rod and fix it under the beam. Draw a line perpendicular to the lower cover from the center point of the beam and to the ends at 3m, 5m and both sides, and mark the center point of each straight line. Figure 2 As shown, the center of the beam and 3m, 5m and ends on both sides are welding points for anti-vibration support seats and support frames, with a total of 8 welded support seats and 20 anti-vibration brackets.

[0039] 2 persons go up to the aerial platform (2 persons stand on one side of the aerial platform and fasten their safety belts. 1 person holds up the support frame, and the other person clamps the threaded frame to fix the support frame. After fixation, spot weld the support frame first, and then spot weld the support frame and the anti-vibration support seat in turn. When spot welding the support frame and the anti-vibration frame, it is necessary to spot weld the center along the drawn line to confirm the position of each support seat. After the spot welding of the support seat is completed, weld both sides at the same time to complete the welding work of the support seat.

[0040] S3. Pre-tighten the tie rods of the two beams at the same time, and continue pre-tightening until the camber of the two beams reaches the reserved deformation value of the camber.

[0041] Pre-tighten the double arch. First, pre-tighten the tie rods of the two beams on the cab side. Move the trolley to the opposite side of the cab. Pre-tighten the tie rods of the two beams at the same time. During the pre-tightening process, repeatedly measure the upper arch data. Pre-tighten according to the data until the upper arch of the two beams reaches the reserved deformation value of the upper arch. The arch value is 1.6S / 1000=26.4mm.

[0042] S4. Determine the heating zone according to the beam deflection curve, calculate the target heating zone and flame shape the beam according to the target heating sequence.

[0043] High temperature heating (700-800°C, cherry red flame, natural cooling by air) is used to flame shape the beam from the center of the beam to the 7m, 4m, and 2m positions on the side of the end beam.

[0044] The layout of the heating zone is determined by the deflection curve of the beam. After correction, the arch curve of each beam should basically conform to the parabola shape, and the height difference of the two beams in the same section should be within the required tolerance range. In order to avoid the superposition of working stress and correction stress, which may cause creep and stress redistribution, thereby generating permanent deformation, that is, deflection again, try to avoid the 3m range of the span when heating. The heating sequence is as follows: Figure 3 Proceed according to the serial number shown.

[0045] The flame temperature and width should be well controlled during flame correction. The heating line (belt) can be estimated as follows:

[0046] N=8h / (L·θ)-1

[0047] In the formula: h is the chord height corresponding to the upper arch arc;

[0048] L—the length of the upper arch arc;

[0049] θ—Rotation angle of the cross section caused by linear heating

[0050] In addition to following the sequence shown in the figure, the heating sequence should be heated first, and then the two sides of the web. The two sides of the web are heated according to the triangle shown in the figure (the heating size is adjusted according to the deformation amount); the heating bandwidth should be 30-40mm wide; the lower cover should be heated by linear heating method, and during the heating movement, it should be lateral swung in the width direction to form strip heating; in order to increase the heating area, the junction of the lower cover and the web should be heated by triangle heating method; the web is heated by point heating method.

[0051] S5. After complete cooling, release the pre-tightening force of the tie rod and determine whether the beam meets the required camber value. If it does, tighten the tie rod.

[0052] After the flame shaping is completed, it needs to be naturally cooled in air, generally for no less than 4 hours. After complete cooling, release the pre-tightening force of the tie rod (loosen the tie rod nut) to let the beam be in a natural state. Measure the data after shaping to meet the required camber value. Use a torque wrench to tighten the tie rod, and the torque range is controlled within 2300~3000N·m.

[0053] Finally, the data is measured and confirmed. It is strictly forbidden to use the crane after the camber value drops again, otherwise it will cause accidents such as the crane beam breaking and deformation. It needs to be corrected and adjusted according to the specifications before it can be used again.

[0054] Finally, it should be noted that, in this article, relationships such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms include, include or any other variations are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0055] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0056] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for repairing the camber of a double-beam crane beam, characterized in that: The following steps are involved: Acquire crane data, and determine the installation points of the support base and the anti-vibration bracket based on the crane data, wherein the crane data includes span data, beam camber data, and lateral bending data; A tie rod is arranged at the bottom of the main beam and the end beam, the tie rod passes through the support seat and is installed at the bottom of the two beams based on the support seat and the anti-vibration bracket; Pre-tighten the tie rods of the two beams at the same time, and continue pre-tightening until the camber of the two beams reaches the reserved deformation value of the camber; Determine the heating zone according to the beam deflection curve, calculate the target heating zone and flame shape the beam according to the target heating sequence; After complete cooling, release the pre-tightening force of the tie rod, determine whether the beam meets the required camber value, and if so, strengthen the tie rod.

2. The method for repairing the girder camber of a double-beam crane according to claim 1, characterized in that: The calculation formula of the heating belt is: N=8h / (L·θ)-1 Where h is the chord height corresponding to the upper arch arc; L is the arc length of the upper arch arc; θ is the rotation angle of the cross section caused by linear heating.

3. The method for repairing the girder camber of a double-girder crane according to claim 1, characterized in that: Several positioning lines perpendicular to the lower cover are arranged along the center point of the beam at 3m, 5m and ends on both sides, and the installation points include the center point of the positioning line, the center point of the beam and the intersection of the positioning line and the beam.

4. The method for repairing the girder camber of a double-girder crane according to claim 1, characterized in that: The heating zone is from the center of the beam to the 7m, 4m, and 2m positions on the end beam side. The target heating sequence is to heat the left end first and from the outside to the inside. The heating temperature is 700°C to 800°C.

5. The method for repairing the girder camber of a double-girder crane according to claim 1, characterized in that: The target heating sequence is to heat the lower cover plate first and then heat the two sides of the web. The lower cover plate is heated by a linear heating method, the web is heated by a point heating method, and the junction of the lower cover plate and the web is heated by a triangle heating method.

6. The method for repairing the girder camber of a double-girder crane according to claim 1, characterized in that: The pull rod is tightened by a torque wrench, and the torque range is controlled within 2300-3000 N·m.

Images