JP2007205162A - Method of reinforcing opening of steel frame girder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of reinforcing an opening of a steel frame girder by which the degree of freedom in design and construction is improved, and a large reinforcing effect is obtained while being safe and simple in structural yield strength. <P>SOLUTION: A center tube 3 is inserted in an opening 1B of a girder web 1A while keeping the steel frame girder 1 erected. Thread grooves 2A formed at the opening edge part are screwed with thread grooves 3A of the center tube 3 to mount a pair of reinforcing steel plates 2, 2 to the center tube 3 so as to hold the girder web 1A. Auxiliary force applicators such as tools are inserted in axial force lead-in holes 5, 5 of the reinforcing steel plates 2, 2 to fix one reinforcing plate 2. In this state, load is applied to the other reinforcing steel plate 2 in a rotational axial force direction, and as it is rotated, greater force is applied. The girder web and the pair of reinforcing steel plates 2, 2 are friction-joined. The auxiliary force applicators are pulled out of the axial force lead-in holes 5, and the axial force lead-in holes 5 are plug-welded to further fix the reinforcing steel plates 2, 2 and the girder web 1A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an opening reinforcing method for a steel beam.

In general, the beam web of a steel beam is often provided with through holes for various types of piping and wiring, and the opening of the beam web is provided with reinforcing means for compensating for the cross-sectional defect. As the beam web opening reinforcing means, there is a ring-shaped reinforcing plate (for example, see Patent Document 1). That is, in Patent Document 1, a cylindrical portion 52a with a male thread projecting from a central hole portion of a ring-shaped reinforcing plate 52 as shown in FIG. 13 is inserted into the web opening 51 of the steel beam 50, and another ring shape is provided. A female threaded cylindrical portion 53a protruding from the central hole of the reinforcing plate 53 is inserted into the web opening 51 from the other side and screwed into the male threaded cylindrical portion 52a, and both the reinforcing plates 52 and 53 are connected to the web of the steel beam 50. A technique for tightening and reinforcing both sides of the opening 51 for reinforcement is disclosed.
JP 7-238635 A

  However, the reinforcing plates 52 and 53 described in Patent Document 1 have a complicated shape. Further, it is difficult for one worker to attach the reinforcing plates 52 and 53 and the washer 54 at the same time, and it is impossible to install them unless two or more people are on the front side and the back side of the beam. Furthermore, depending on the thickness of the beam web, there is a limit to the reinforcement range of the fixed threaded cylinder part 53a, the male threaded cylinder part 52a, and the washer 54. The reinforcing plates 52 and 53 having the female threaded cylinder part 53a and the male threaded cylinder part 52a must be prepared.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a steel beam opening reinforcement method that improves the degree of freedom of design and construction, is safe and simple in terms of structural strength, and provides a greater reinforcement effect.

  For this reason, the invention related to the first steel beam opening reinforcing method is such that a central tube having a thread groove formed on the outer surface thereof is inserted into the opening formed in the beam web of the steel beam, and the beam web is sandwiched between them. A screw groove formed on an opening edge of a pair of reinforcing bodies from outside is screwed into a screw groove of the central tube, and the beam web and the pair of reinforcing bodies are friction-bonded and fixed. And

  In the invention relating to the second steel beam opening reinforcement method, in the first invention, an axial force introducing hole is formed in the pair of reinforcing bodies, and a force assisting material is inserted into the axial force introducing hole. By applying rotational force to the pair of reinforcing bodies, the beam web and the pair of reinforcing bodies are friction-bonded and fixed, and then the axial force introduction hole is filled by welding to form the pair of reinforcing bodies and the beam. The web is welded and fixed.

  INDUSTRIAL APPLICABILITY The present invention can provide an opening reinforcing method for a steel beam that has a higher degree of freedom in design and construction, is safe and simple in structural strength, and provides a greater reinforcing effect. In addition, when the central tube with one reinforcing body attached is inserted into the opening formed in the beam web of the steel beam and the other reinforcing body is attached from the other side so as to sandwich the beam web, One person can perform the installation work alone. Furthermore, by forming a thread groove on the outer surface of the central tube over a predetermined range, it is possible to cope with beam webs having different thicknesses without having to provide many kinds of reinforcing bodies.

  Embodiments of the present invention will be described below with reference to FIGS. First, a circular opening 1B is formed in an intermediate portion of a beam web 1A of a steel beam 1 which is a base material to be reinforced with an H-shaped cross section. Then, the reinforcing work is left without standing the steel beam 1, and the hollow cylindrical central tube 3 (see FIG. 5) in which the thread groove 3A is formed in the entire outer surface (over the entire length) is used as the beam web. Insert into 1A opening 1B.

  Next, a pair of reinforcing steel plates 2 and 2 (see FIG. 4) each having a circular opening formed in the central portion are respectively connected to the screw grooves 2A formed on the opening edge portions thereof from the outside to the screw grooves 3A of the central tube 3. And are attached so as to sandwich the beam web 1A.

  Thereafter, a force assisting material such as a jig is inserted into a plurality of (for example, two at every 180 degrees) axial force introduction holes 5 and 5 provided in the reinforcing steel plates 2 and 2, and one reinforcing steel plate 2 is inserted. A larger force is applied while rotating the other reinforcing steel plate 2 while applying a load in the direction of the rotational axial force in a state in which is fixed. In this case, a large force is applied until the stress is transmitted by the friction force generated between the beam web 1A and the pair of reinforcing steel plates 2 and 2 and the friction welding is performed. The friction bonding in this case is not a state where the pair of reinforcing steel plates 2 and 2 are fastened to the beam web 1A by hand tightening, but is further tightened using a jig or the like as described above. .

  When the application of such a large force is finished, the auxiliary force material such as the jig is removed from the axial force introduction hole 5 and the axial force introduction hole 5 is filled by plug welding. The reinforcing steel plates 2 and 2 and the beam web 1A are firmly fixed, and further, the reinforcing steel plates 2 and 2 are prevented from loosening, slipping or peeling. That is, due to the above-described frictional joining, slippage between the beam web 1A and the reinforcing steel plate 2, 2 outer end portion is less likely to occur, and separation between the beam web 1A and the reinforcing steel plate 2, 2 intermediate portion is less likely to occur, The reinforcing steel plates 2 and 2 and the beam web 1A are firmly fixed by the plug welding to further prevent the reinforcing steel plates 2 and 2 from loosening, slipping or peeling, and the beam web 1A can be prevented by this friction welding or further plug welding. Even if a force (bending moment) to be deformed is applied, the entire contact surface between the reinforcing steel plates 2 and 2 and the beam web 1A resists this force, so that the amount of deformation can be reduced.

  In addition, if the reinforcing steel plates 2 and 2 are pretreated with blasting or red rust on the side in close contact with the beam web 1A of the steel beam 1 so that stronger friction is generated, the effect is obtained. Greater than.

  Next, the case of a steel reinforced concrete (SRC) beam will be described with reference to FIG. 1 and 2, the hollow cylindrical sleeve tubes 4 and 4 as shown in FIG. 6 are utilized by utilizing the thread groove 3A processed on the outer surface of the central tube 3 used when the reinforcing steel plates 2 and 2 are mounted. The sleeve tubes 4 and 4 are respectively attached to both end portions of the central tube 3 by screwing the screw grooves 4A formed on the inner surfaces of the end portions into the screw grooves 3A of the central tube 3.

  Since the sleeve tubes 4 and 4 are processed with a thread groove 4A on the inner side, it is easy to ensure a predetermined length after mounting. Moreover, it is not always necessary to assemble at the production factory, and may be assembled at the construction site for transportation considerations.

  In addition, in the case of the friction joining of the above embodiment, in order to enhance the reinforcing effect, it is not always necessary to perform the plug welding, and the reinforcing steel plates 2 and 2 and the beam web 1A can be firmly fixed.

  Next, another embodiment will be described with reference to FIGS. First, a circular opening 11B is formed in an intermediate portion of a beam web 11A of a steel beam 11 that is a base material to be reinforced with an H-shaped cross section. Then, the reinforcing work is left without standing the steel beam 11, and the hollow cylindrical central tube 13 in which the thread groove 13A is formed in the entire outer surface (over the entire length) is formed in the opening 11B of the beam web 11A. Insert into. Next, a pair of reinforcing steel plates 12 and 12 having a circular opening formed at the center is screwed with a screw groove 12A formed at the opening edge of the pair of reinforcing steel plates 12 and 12 into a screw groove 13A of the center tube 13, and the beam web Attach so as to sandwich 11A.

  Thereafter, a force assisting material such as a jig is inserted into a plurality of (for example, four at every 90 degrees) axial force introduction holes 15 and 15 provided in the reinforcing steel plates 12 and 12, and one reinforcing steel plate 12 is attached. In a fixed state, a load is applied to the other reinforcing steel plate 12 in the direction of the rotational axial force, and the operator applies a force while rotating the steel plate 12 by hand tightening.

  In this case, the pair of reinforcing steel plates 12 and 12 may be fixed so that the beam web 11A is sandwiched between the beam webs 11A by hand tightening directly by an operator's hand without using a jig or the like. In any case, the pair of reinforcing steel plates 12, 12 and the beam web 11A are fixed with no gap.

  Even if a jig or a tightening machine is used, the introduction of the rotating force is stopped before the beam web 11A and the pair of reinforcing steel plates 12 and 12 are frictionally joined. Then, after stopping the introduction of the rotating force, the axial force introduction hole 15 becomes plug welds 20 and 21 in order to enhance the reinforcing effect, and the reinforcing steel plates 12 and 12 and the beam web 11A are firmly bonded by this welding. To fix.

  FIG. 9 is a side view for explaining the operation principle of the present embodiment. The operation when an external force is applied to the steel beam 11A will be described. First, the screw grooves 12A of the reinforcing steel plates 12, 12 and the screws of the central tube 13 are described. In the part A of the screw joint with the groove 13A, the reinforcing steel plates 12 and 12 are sandwiched between the near side and the far side of the beam web 11A, and the beam web 11A is fixed together with the central tube 13.

  As the external force increases, the amount of out-of-plane deformation of the beam web 11A increases. However, since the pair of reinforcing steel plates 12 and 12 are fixed to the beam web 11A, the deformation of the beam web 11A is suppressed.

  Further, since the beam web 11A is also partially welded to the reinforcing steel plates 12 and 12 by the plug welding 20 (on the one reinforcing steel plate 12 side) and the plug welding 21 (on the other reinforcing steel plate 12 side), In part C, since the reinforcing steel plates 12 and 12 and the beam web 11A are integrated, deformation of the beam web 11A is suppressed and the reinforcing effect is great.

  Furthermore, in the A portion of the screw joint portion between the screw groove 12A of the reinforcing steel plates 12 and 12 and the screw groove 13A of the central tube 13, the central tube 13 at the center of the opening 11B other than the reinforcing steel plates 12 and 12 is the beam web 11A. Since the three-dimensional torsional deformation is suppressed, the plastic deformation ability is remarkably improved.

  When a proof stress test was performed using a force test apparatus as shown in FIG. 10, the MR skeleton curve diagram of FIG. 11 could be obtained. In addition, F and G of this FIG. 11 are steel beams which implemented the reinforcement method of this embodiment, D implemented for the comparison of this embodiment is a steel beam which does not have an opening, E is a non-reinforcing which has an opening. It is a steel beam.

  In this case, the applied force repeatedly applies horizontal load to the top of the beam, the unopened beam D and the open unreinforced beam E up to the + side ultimate strength, and the 9 mm reinforced steel plate F and the 12 mm reinforced steel plate G have a member angle 1 / I went to 10.

  The yield strength was recovered by the method of reinforcement according to the present embodiment. In particular, the effect of the maximum yield strength was great, and the decrease in the yield strength after showing the maximum yield strength was gradual. As a result, it was confirmed that the ultimate yield strength was dramatically increased.

  More specifically, as can be seen from the results of the proof stress test, it can be seen that the deformability of the steel beams F and G of the present embodiment is dramatically increased from the non-open beam D when the present reinforcing method is performed. Under the current standards, seismic design that depends on the toughness of the building is performed, and it is considered desirable to have a structural design that forms a beam yielding-preceding type overall yield mechanism in the event of a large earthquake. For this reason, sufficient toughness is required for the portion where the hinge formation at the end of the beam is expected, but this reinforcement method exceeds the non-opening beam (usual use state of the beam) D as can be seen from the strength test results. Compared with the deformation capability of the unreinforced opening E, the plastic deformation capability is greatly improved.

  For the above reasons, in the design method, since the seismic performance of the building is improved by actively using this reinforcement method for the plastic hinge forming part at the beam end, the size of the steel beam can be reduced, or the column spacing The steel structure design method by the idea completely different from the conventional design can be expected.

  In other embodiments as well, a sleeve pipe (not shown) for steel reinforced concrete construction is attached by screwing a screw groove formed on the inner surface of the end into the screw groove 13A of the central pipe 13. Also good. In this way, in both of the above embodiments, the sleeve tube can be attached using the screw groove for the extra length of the central tube, so the end of the sleeve tube when attached without depending on the construction accuracy. The length (from the beam web) can be adjusted to eliminate inconveniences such as protruding or shortening from the concrete formwork, and there is no need to attach and transport the sleeve tube to the steel beam at the manufacturing plant. Therefore, the loading rate to the transport vehicle can be improved.

  As described above, the beam web of the steel beam and the reinforcing steel plate are fixed by fixing that does not lead to frictional coupling or friction welding, and the axial force introduction hole of the reinforcing steel plate is further filled by plug welding so that the reinforcing steel plate and the beam are fixed. The web is fixed, but instead of this plug welding, both reinforcing steel plates and beam webs may be provided with insertion holes, and both reinforcing steel plates and beam webs may be fixed with bolts and nuts inserted into the insertion holes. The fixing method can be selected according to the working environment.

  In this case, an insertion hole is opened at the position of the other reinforcing steel plate corresponding to the beam web and the axial force introduction hole of the one reinforcing steel plate (not limited to this, but may be a newly formed insertion hole), and the one reinforcing steel plate The bolt is inserted into the axial force introduction hole of the steel plate and the beam web and the insertion hole of the other reinforcing steel plate and tightened and fixed with a nut, but this fixing is at least two symmetrical positions across the center of each reinforcing steel plate. Do. Therefore, the fixing of the reinforcing steel plate and the beam web is not plug-welded, or even if it is a very small amount, the beam web is hardly affected by heat, and deformation and distortion of the steel beam due to welding heat do not occur. It is hard to occur.

  The axial force introduction holes of the pair of reinforcing steel plates are not limited to filling the plug steel by plug welding and the reinforcing steel plates and the beam web are fixed, but the outer edges of the pair of reinforcing steel plates and the beam web may be fillet welded. .

  Further, by forming a screw groove on the outer surface of the central tube over a predetermined range, for example, over a wide range if it is wide, and further over the entire region, it is possible to reinforce the beam webs having different thicknesses. Therefore, it is not necessary to provide many types of reinforcing steel plates, and even one type can be handled.

  Further, the reinforcing steel plate may be mounted from both sides so as to sandwich the beam web in a state where the central tube is inserted into the opening of the beam web, or the central tube in a state where the one reinforcing steel plate is mounted. The other reinforcing steel plate may be attached from the other side so as to be inserted into the opening and sandwich the beam web, and the beam web and the pair of reinforcing bodies may be fixed. In this latter case, one worker can perform the installation work alone.

  Next, another embodiment will be described with reference to FIG. First, a circular opening 31B is formed in an intermediate portion of a beam web 31A of a steel beam 31 which is a base material to be reinforced with an H-shaped cross section. Then, the reinforcing work is left without standing the steel beam 31, and the hollow cylindrical central tube 33 is inserted into the opening 31B of the beam web 31A. Next, a pair of reinforcing steel plates 32 and 32 each having a circular opening at the center are disposed so as to sandwich the beam web 31A from the outside.

  In this case, the reinforcing steel plates 32 and 32 are arranged so as to sandwich the beam web 31A so that the central tube 33 inserted into the opening 31B of the beam web 31A fits into the openings of the pair of reinforcing steel plates 32 and 32. To do.

  Thereafter, the central pipe 33 and the reinforcing steel plates 32 and 32 are partially welded and fixed by partially welding (several places) the outer edge of the central tube 33 and the opening edges of the reinforcing steel plates 32 and 32. . Thereby, the beam web 31A and the pair of reinforcing steel plates 32 and 32 can be firmly fixed. Therefore, various effects as described above can also be obtained by this embodiment. Instead of this welding 35, it may be fixed with an adhesive or the like.

  In addition, although the reinforcement steel plate in all the embodiments may be made of cast iron or forging, it may be made of a rolled steel plate because of a problem in the manufacturing process such as high cost. Further, the shape of the reinforcing steel plate is not limited to a circular shape, but may be a polygonal shape or other shapes, and further does not need to be a plate material.

It is a vertical front view of the state which reinforced the steel beam. It is a side view of the state which reinforced the steel beam. It is a vertical front view of the state which attached the sleeve pipe | tube to the steel beam of the reinforced state. It is a figure which shows a reinforced steel plate. It is a longitudinal cross-sectional view of a center pipe. It is a longitudinal cross-sectional view of a sleeve pipe. It is a side view of the state which reinforced the steel beam which shows other embodiments. It is XX sectional drawing of FIG. It is side views, such as a reinforced steel plate, for demonstrating the operation principle of other embodiment. It is the outline of applied force which performed the proof stress test. It is the MR skeleton curve figure which calculated | required the experimental result. It is a side view of the state which reinforced the steel beam which shows other embodiments. It is the side view (A) which shows a prior art example, sectional drawing (B) of an arm part, and the expanded sectional view of A part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Steel beam 1A, 11A Beam web 1B, 11B Opening 2,12 Reinforced steel plate 2A, 12A Thread groove 3,13 Central pipe 3A, 13A Thread groove 4 Sleeve pipe 5,15 Axial force introduction hole 8 Friction joint surface 20, 21 Plug welding

Claims (2)

  Screws formed on the opening edges of a pair of reinforcing bodies from the outside by inserting a central tube having a thread groove formed on the outer surface of the opening formed in the beam web of the steel beam An opening reinforcing method for a steel beam, wherein a groove is screwed into a thread groove of the central tube, and the beam web and the pair of reinforcing bodies are fixed by friction bonding.   The beam web and the pair of reinforcements are formed by opening an axial force introduction hole in the pair of reinforcements, and inserting a force assisting material into the axial force introduction hole to give a rotational force to the pair of reinforcements. 2. The steel beam opening according to claim 1, wherein the axial force introduction hole is filled by welding and the pair of reinforcing bodies and the beam web are welded and fixed after the body is frictionally joined and fixed. Reinforcement method.

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