KR20080037472A - Method for preventing bolt releasing in steel structures using structural bolt adhesive - Google Patents

Abstract

A bolt releasing prevention method of steel structures using structural bolts adhesives is provided to improve safety of the steel structures, and to reduce safety inspection costs by securing powerful adherent force between plates. A bolt releasing prevention method of steel structures using structural bolts adhesives(30) comprises the steps of: forming a plurality of bolt holes in mother material of the steel structures; forming a plurality of bolt holes in connecting plates to be attached in front and rear surface of the mother material; locating the connecting plates in the front and rear surface of the basic material, and aligning a position of the bolt holes; inserting bolts(5) into the bolt holes respectively; coating liquid or solid bolts adhesives to a screw part of the bolts; and linking a nut to the respective bolt and tightening so that predetermined tensile strength is introduced between the bolt and the nut.

Description

Method For Preventing Bolt Releasing In Steel Structures Using Structural Bolt Adhesive}

1A and 1B show a state in which bolts 3a are loosened in a lower flange of a steel plate bridge structure 1 to which bolts are fastened by a conventional mechanical bolt fastening method.

2A and 2B show a state in which bolts 3a are loosened at side 11 and bottom 12 of steel box girder bridge structure 10 to which bolts are fastened by a conventional mechanical bolting method.

3A and 3B show a state in which the bolts 3a fastened in a conventional manner are corroded and loosened by leakage.

Fig. 4 shows a state in which the screw fixing agent 30 is applied to the screw portion of the bolt 5 by the bolt loosening prevention method of the steel structure using the structural screw fixing agent of the present invention.

5A and 5B show a state in which the box girder is bound by bolts to which the thread fixing agent is applied by the bolt loosening prevention method of the steel structure using the structural screw fixing agent of the present invention.

6A and 6B show a state in which reinforcing bars are connected to each other by using a screw fastener to the mechanical screw joint 42 of the large diameter rebars 40 and 40 '.

Figures 7a and 7b show the application of the structural threadlocker according to the invention on the surface of the threaded part of the bolt 5, and Figure 7c shows that the threadlocker is applied to the surface of the threaded part of the bolt 5 The state is shown.

8 illustrates the principle that the screw fixing agent composed of an anaerobic adhesive component is bonded and hardened in contact with a metal bolt and nut in the bolt loosening prevention method of a steel structure using the structural screw fixing agent according to the present invention.

9A and 9B show automatic applicators 35 and 37 for applying a threadlocker to the threaded portion of the nut in the present invention.

10A and 10B show manual applicators 38 and 39 for use in small bolting operations in the present invention.

11 shows a stick-type thread locker used to perform the bolt loosening prevention method of steel structures using the structural screw locker according to the present invention.

Figure 12 is a schematic diagram of the equipment for the vibration test in the horizontal direction of the bolted joint applied by applying the structural screw fastener according to the present invention.

13A and 13B show a state in which a strain gauge 63 is inserted into the bolt 5 for use in the test of FIG.

14 is a graph comparing tension holding performance of bolt fastening units for a plurality of screw fixing methods.

Fig. 15 is a graph of the horizontal vibration test results shown in Figs. 12, 13A, and 13B.

Figure 16 illustrates a state of fastening the bolt using a torque wrench to test the performance of the bolt loosening prevention method of the steel structure using the structural screw fixing agent according to the present invention.

17 is a graph showing the relationship between the tightening torque of the steel bolt and the introduction tension in the bolt loosening prevention method of the steel structure using the structural screw fixing agent according to the present invention.

18 is a graph showing the result of the tension retention performance test of the bolt connection portion fastened according to the present invention.

19 is a graph showing the results of the high-temperature strength test of the bolted connection portion fastened according to the present invention, and FIG.

Fig. 21A shows a test piece for fatigue test manufactured to test the effect of the bolt loosening prevention method of a steel structure using the structural screw fixing agent according to the present invention.

FIG. 21B shows the process of applying the threadlocker to the fatigue test specimen of FIG. 21A, and FIG. 21C shows the finished specimen as a result.

22 is a graph showing the results of a static test on the load-displacement relationship of the bolt connection to which the structural screw fixing agent according to the present invention and the bolt connection to which the screw fixing agent is not applied.

* Description of the symbols for the main parts of the drawings *

1: steel structure 2a, 2b, 20: joint plate

3a, 4a: bolt 3b: washer

3c, 4c: nut 5: bolt

5a: thread 5b: screw bone

5d: wiring 6: nut

10: steel box girder 11: side of box girder

12: bottom of box girder 20 ': junction

30, 30a: adhesive 31: adhesive application tool

31: stick type screw lock container 32: adhesive container

33: Test piece 35: Automatic screw applicator

35a: Tip 36: glue gun

36a: connector 37: screwlocker automatic applicator

38: Manual Screw Applicator 38a: Nozzle

39: manual glue gun 39a: cylinder

39b, 39c: adhesive container 40, 40 ': rebar

41a: bolt portion 42: joint portion

42a: nut part 50: pier

51: box girder 52: upper flange

53: connecting plate 54: girder shell

55: lower column 56: upper column

57: diagonal strut 58: locking plate

59: gusset 60: guideway

61: air hammer 62: measuring strip

63: strain gauge 70: the base material

71, 72: upper joint plate 71a: bolt hole

75: torque wrench

The present invention relates to a method for preventing bolt loosening of steel structures using structural screw fixing agents, and particularly, to prevent loosening of bolt connection parts that bind steel materials in various civil structures or building structures subjected to severe mechanical vibration. Or it relates to a bolt loosening prevention method of the steel structure to prevent the defect of the joint of the steel structure by applying a bolt after applying to the screw surface of the nut.

Today, screw assembly is the most important detachable part used in machine assembly, mounting and repair. Nevertheless, screw assembly is generally widely used, and most users are not aware of the problems caused by screw assembly, and in-depth analysis of screw functions has not been made in reality.

The screw assembly is widely used in the general industrial field as well as in civil engineering, construction, etc. In particular, high-strength bolted joints based on the principle of screw assembly together with welding are used as the most effective joints. However, the bolt joint part by the screw assembly principle of the steel structure is a situation that various defects such as loosening of the bolt and corrosion of the joint due to various environmental factors as well as repeated impact and load.

The ability to form free structures by joints between members is the greatest advantage of steel structures, but at the same time, defects in these joints determine the integrity of the overall structure, which, on the other hand, is a major disadvantage.

Joints between members by screw assembly have been widely used for a long time in the general machinery industry such as the automobile industry, and methods of coping with various defects of screw assembly parts have been researched and developed and applied. However, in the field of civil engineering and construction, the interest and countermeasures are insignificant compared to the importance of facilities, and they are taking passive measures such as repair and reinforcement during public use. It contains risks that may affect the environment.

1A and 1B show a state in which bolts 3a are loosened in a lower flange of a steel plate bridge structure 1 to which bolts are fastened by a conventional mechanical bolt fastening method.

Bolted joints for connecting steel structures include friction joints, tensile joints, shear joints, etc. of high tension bolts. These joints are bound by applying a proper tension to the bolt by applying torque to the nut, and the bolt is loosened in the long term due to external large and small shocks and vibrations applied to the structure. In the case of high tension bolt friction joints, if bolt loosening occurs, even if the loosening is very fine, the frictional force of the steel joint surface depending on the tension of the bolt is lowered. Along with the loss, the joint loses cohesion, causing initial slippage. The destruction of these joints has a number of problems that may cause safety problems of the structure.

1A and 1B, it can be seen that a plurality of bolts 3a are loosened from the joint plates 2a and 2b connecting the lower flanges of the steel plate-shaped bridge structure 1 which is in common use. Although there are some bolts 4a and nuts 4c that have not yet been loosened in Fig. 1a, the already loosened bolts 3a and nuts 3c lose their binding function and thus the load is concentrated and destroyed. Is expected. In Figs. 1A and 1B, reference numeral 3b denotes a washer.

2A and 2B show a state in which bolts 3a are loosened at side 11 and bottom 12 of steel box girder bridge structure 10 to which bolts are fastened by a conventional mechanical bolting method.

Referring to Figures 2a and 2b, it is shown that the bolt loosening occurred in the joint 20 of the steel box girder bridge 10. In Fig. 2a, symbol ⓐ indicates a portion where one box girder 10 sags downward due to a load, and symbol ⓑ indicates that a gap is opened due to sagging of a joint. Also, the symbols ⓒ and ⓓ indicate that the frictional force between the side surfaces 11 and the bottom surface 12 is completely lost due to the loosening of the bolts. In addition, in Fig. 2b, the symbol ⓔ indicates that the bolt is loosened at the joint joint plate 20 of the side 11 of the box girder 10, the symbol ⓕ indicates the loosening gap of the nut 3c, and the symbol ⓖ is The loosening of the bolts indicates that the bottom of the box girder 10 and the joint plate 20 are severely opened, and the symbol ⓘ indicates the gap that is open, and the symbol ⓙ indicates the bolts where the loosening of the bolt proceeds to the end of the thread.

3A and 3B show a state in which the bolts 3a fastened in a conventional manner are corroded and loosened by leakage. After the bolts of the seam are loosened at the initial stage, the loosening is accelerated to completely lose the fastening force of the bolts, which leads to leakage, which causes corrosion of the member and the bolts. If corrosion occurs, breakage of the joint is likely to occur due to cross-sectional loss of the bolt.

As described above, in order to prevent loosening of the bolt joint, which is a major risk factor for the safety of the steel structure constituting the civil and building structures, it was necessary to apply a screw fixing agent to the bolt or nut and fasten the bolt.

The present invention is to prevent the bolt loosening of the steel structure joint by applying a structural screw fixing agent to the screw surface of the bolt or nut when binding the steel structure in various civil structures or building structures subjected to severe mechanical vibration It is an object of the present invention to provide a method for preventing bolt loosening of steel structures using structural screw fixing agents.

In order to achieve the above object, the bolt loosening prevention method of a steel structure using the structural screw fixing agent provided by the first embodiment of the present invention is a method of joining a steel structure constituting a civil structure or a building structure, the base material of the steel structure Forming a plurality of bolt holes in the hole; Forming a plurality of bolt balls in the joint plates to be attached to the front and rear surfaces of the base material; Positioning the joint plates on the front and rear surfaces of the base material and matching the bolt holes with each other; Inserting a plurality of bolts into the bolt holes, respectively; Applying a liquid or solid threadlocker to the threads of the bolts; And tightening a nut to each of the bolts and tightening a predetermined tension to be introduced between the bolts and the nuts.

In addition, the bolt loosening prevention method of the steel structure using the structural screw fixing agent provided by the second embodiment of the present invention to achieve the above object, in the joining method of the steel structure constituting the civil structure or building structure, steel structure Forming a plurality of bolt holes in the base metal; Forming a plurality of bolt holes in the joint plates to be attached to the front and rear surfaces of the base material; Positioning the joint plates on the front and rear surfaces of the base material and matching the bolt holes with each other; Inserting a plurality of bolts into the bolt holes, respectively; Applying a liquid or solid screwlock to the threads of the nuts to be fastened to the bolts; And tightening the nuts to the bolts and tightening a predetermined tension between the bolts and the nuts, respectively.

And, in order to achieve the above object, the bolt loosening prevention method of the steel structure using the structural screw fixing agent provided by the third embodiment of the present invention, the maintenance method of the steel structure constituting the existing civil structure or building structure According to claim 1, characterized in that the screw fixing agent penetrates the liquid screw fixing agent to the bolt and nut fastening portion installed in the joint plate connecting the base materials in the steel structure so that the screw fixing agent is filled and hardened in the fastening portion of the bolt and nut. It is done.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and effect of the bolt loosening prevention method of the steel structure using the structural screw fixing agent according to the present invention.

Fig. 4 shows a state in which the screw fixing agent 30 is applied to the screw portion of the bolt 5 by the bolt loosening prevention method of the steel structure using the structural screw fixing agent of the present invention. In Fig. 4, reference numeral 5a denotes a screw thread, and 5b denotes a screw bone. Screw fixing agent 30 may be contained in a predetermined adhesive application tool 31 as described later can be applied automatically or manually.

The screw fixing agent according to the present invention is a screw fixing adhesive used in the mechanical field is a component adjusted to be suitable for large-scale bolting in the civil engineering field, basically based on dimethacrylate ester, room temperature (25 Specific gravity) is about 1.1.

Structural screw fixing agent used in the present invention can be largely divided into a high-strength anaerobic screw fixing agent of the hardening type and a high viscosity penetrating anaerobic screw fixing agent of a low viscosity (12cp) fast curing type.

Among these, the hardening type high strength anaerobic screw fixing agent is a liquid or gaseous anaerobic screw fixing agent applied to a thread of a bolt or nut of a high tension bolt friction joint, and is applied using a brush or a spray. This type of hardening type threadlocker takes about five days for initial hardening after bolt fastening and slows down the hardening time for inspection of the bolt fastening.

In addition, the low-viscosity fastening type high-strength penetrating anaerobic screw fixing agent is a method of applying an anaerobic screw fixing agent to a bolt connection part of a steel structure which is already in common, or a structure in which a bolt is fastened in advance. And the threadlocker is penetrated between the threads of the nut of the bolt after the inspection is finished. The penetrating anaerobic screw fixing agent is low in viscosity and can be added in the antigravity direction.

The high strength anaerobic screw fixing agent of the hardening type can be easily applied to a new structure, and the high viscosity penetrating anaerobic screw fixing agent of the low viscosity fast curing type is used to repair and reinforce bolted joints of a new structure and a common structure. Applicable

In the present invention, the anaerobic screw fixing agent applied to the thread of the bolt or nut is hardened by an anaerobic reaction from the screw thread of the bolt and nut are combined, and the hardened screw fixing agent bonds the threads of the bolt and nut to the external Prevents bolts from loosening from shock and vibration.

In addition, the thread of the bolt and nut of the bolt connection part has a gap between the threads opposite to each other, and the gap is narrowed when the bolt is released, and the bolt joint portion of the bolt joint in which the structural screw stabilizer is constructed by the method of the present invention is provided. In this case, since the screw fixing agent having a large compressive strength is filled in the voids between the threads and cured, the voids cannot be narrowed to prevent bolt loosening.

5A and 5B show a state in which the box girder is bound by bolts to which the thread fixing agent is applied by the bolt loosening prevention method of the steel structure using the structural screw fixing agent of the present invention.

5a schematically illustrates a shape in which a box girder 51 is installed on an upper flange 52 of a pier 50 and a top plate (not shown) is placed on a box girder 51 in a civil structure such as a bridge. . The box girder 51 which is continuously installed is fixed by fastening the bolt and nut 3c by using the connecting plate 53. When the bolt and nut 3c attached to the connecting plate 53 of the box girder 51 are repeatedly subjected to the tensile load and the moment load due to the change of the live load on the bridge, the loosening occurs. In this case, the present invention Use of bolted joints using structural screw fasteners can prevent loosening.

5b shows a state in which a reinforcing member installed in the box girder of FIG. 5a is securely connected by a bolt loosening prevention method of a steel structure using the structural screw fixing agent of the present invention. The reinforcing plate 59 vertically attached on both side girder outer plates 54 of the box girder 51 is connected to the lower column 55 and the upper column 56, and the diagonal brace 57 is a locking plate. It connects to the lower column 55 via (58). The bolts / nuts used to connect each of the struts and the locking plate are subjected to the moment load and the tension load that change frequently, so that no matter how tightly they are tightened, they will eventually loosen. Even if the bolts / nuts are checked for looseness at any time, it is difficult to find out whether they are loosened, and the safety inspection cost for such work is unnecessarily increased. Thus, by applying and fastening the structural screw fixing agent of the present invention to the bolts and nuts that are repeatedly installed in the vibration part, it is possible to greatly improve the safety of the joint of the steel structure.

The joining method of the steel structure using the structural screw fixing agent of the present invention is a high-strength bolt connection of the steel structure of civil engineering and construction, anchor bolt connection of civil engineering tunnel structure, high-tension bolt connection of civil railway structure and mechanical screw joint of large diameter reinforcement It can be applied to joints and other bolt structures of general structures.

6A and 6B show a state in which reinforcing bars are connected to each other by using a screw fastener to the mechanical screw joint 42 of the large diameter rebars 40 and 40 '.

6A and 6B, a thread fixing agent is applied to a nut thread 42a of a mechanical threaded part 42 of a large diameter rebar 40 and 40 'to apply a bolt thread of the rebar 40 and 40'. 41a) can be completely hardened in advance by assembling the reinforcing bars 40 and 40 'and unscrewing the screw fastening part during transportation and mounting of the assembled reinforcing bars.

Figures 7a and 7b show the application of the structural threadlocker according to the invention on the surface of the threaded part of the bolt 5, and Figure 7c shows that the threadlocker is applied to the surface of the threaded part of the bolt 5 The state is shown.

After the threadlocker is applied by the method shown in FIG. 7A or 7B, the threadlocker 30 is penetrated between the bolt 5 and the thread 5a of the nut and cured, and the bolt and the nut are bonded together. It fills the gap between the threads and prevents the bolt from permanently loosening under severe vibration.

As shown in Fig. 7C, the thread fixing agent 30 of the adhesive component is applied to the threaded portion of the bolt 5, and reference numeral 33 denotes a test piece for performing a tension test or the like.

FIG. 8 illustrates the principle of the bolt fixing agent composed of an anaerobic adhesive component in contact with a metal bolt and nut in the method of preventing bolt loosening of a steel structure using the structural screw fixing agent according to the present invention.

The threadlocker developed in the present invention is a one-component material that is cured at room temperature when it is not in contact with oxygen, and the curing component in the liquid is in an inactive state during contact with oxygen in the atmosphere. Hardening proceeds rapidly when the threadlocker cannot take oxygen in the atmosphere by coupling with components (bolts and nuts), especially when it is in contact with metal at the same time.

The hardening process of the screw fixing agent which is hardened by the anaerobic reaction can be explained by the drawings of ① to ④ of FIG. 8. First, the screw fixing agent is supplied with constant oxygen in the fluid state such as ① to maintain a stable state. When the screw fixing agent is pressed to the bonding site and the oxygen supply is interrupted as in ②, the peroxide is changed into free radicals through the reaction with the metal ions. This free radical begins to form a polymer chain, as in e.g., and finally, in the hardened state ④, it remains a solid structure with interconnected polymer chains.

On the other hand, the liquid screw fixing agent penetrates even the smallest gap between the bolt and the nut to fill the adhesive site due to the capillary effect. The hardening process is facilitated by the contact of the screwlocker with the metal surface, which causes catalysis.

9A and 9B show automatic applicators 35 and 37 for applying a threadlocker to the threaded portion of the nut in the present invention.

The automatic applicators 35 and 37 of Figs. 9A and 9B are equipment for automatically applying a liquid coating screw fixing agent, and are used when replacing bolts in bolted joints of new or shared structures. Application is possible.

The automatic spreader 35 of FIG. 9A ejects the liquid threadlocker through the nozzle of the tip 35a portion and applies the threadlocker to the thread of the nut 6.

In the automatic applicator kit 37 of FIG. 9B, a liquid screw fixing agent is supplied from the main body to the glue gun 36 through the connecting pipe 36a, and the thread fixing agent is applied to the threads of the nut with the glue gun 36. do.

The screw fixing agent used in the present invention includes a screw hardening method of a slow hardening method developed in consideration of a period for fastening torque inspection after fastening the bolt and a fast hardening method screw fastening agent developed suitable for a place requiring fast curing.

In addition, the method of applying the thread fixing agent to the bolted fastening part includes a method of applying to the thread 5a of the bolt 5 as shown in Figs. 7A and 7B and a method of applying to the thread of the nut as shown in Figs. 9A and 9B. However, where a large amount of coating work is required, such as a new structure, a method of applying a nut thread by an automated equipment is appropriate, and since it is possible to apply and store it in advance, there is no process added to the bolt fastening process. There is also a method of collectively applying with a brush or the like to the bolt threads arranged in the middle of the fastening process.

10A and 10B show manual applicators 38 and 39 for use in small bolting operations in the present invention. The manual applicator 38 of FIG. 10A discharges the threadlocker manually through the nozzle 38a, and the manual glue gun 39 of FIG. 10B inserts the adhesive containers 39b and 39c into the cylinder 39 and then triggers it. Pulling will squeeze out the container and release the adhesive.

11 shows a stick-type thread locker used to perform the bolt loosening prevention method of steel structures using the structural screw locker according to the present invention.

11, since the stick-type screw fixing agent 31 is contained in the lip gloss-type container 31a, it is easy to carry and has an advantage of being easily applicable in the field. This stick-type threadlock 31 is particularly suitable for small bolting operations.

Figure 12 is a schematic diagram of the equipment for vibration testing in the horizontal direction of the bolted joints applied by applying the structural screw fastener according to the present invention, Figures 13a and 13b is a bolt (5) for use in the test of Figure 12 The state in which the strain gauge 63 was inserted in the inside is shown.

The vibration test measuring apparatus of FIG. 12 inserts a test part 5 'having a bolt connection into the air hammer 6 with a guideway 60 interposed therebetween, and vibrates horizontally from -a to a with the force of Fv. . At this time, reference numeral 62 in Fig. 12 indicates a measurement strip.

This horizontal vibration test is used as a method for measuring the degree of bolt loosening of the bolted joint due to external vibration, and is applied by applying vibration in the horizontal direction with the member which is the main cause of bolt loosening. In addition, in order to accurately measure the bolt tension, a strain gauge 63 is inserted into each bolt as shown in FIGS. 13A and 13B.

In Figs. 13A and 13B, the strain gauge 63 is embedded in the bolt 5, and the wiring 5d is connected with the measuring instrument main body to transmit the displacement as an electric signal.

14 is a graph illustrating a comparison between tension holding performances of bolt fastening units for a plurality of screw fixing methods.

Referring to Fig. 14, three methods located at the top of the graph, namely, the general bolt A1, the bonded bolt A2 and the toothed flange bolt A3 using the screw fixing system, are resisted as the number of load repetitions increases. It may be judged that this appears similar. However, comparing these three cases can yield quite important results. The bonded bolts A2 and toothed flange bolts A3 slightly decrease in stress as the load repeat count increases, and the reduction width is further expanded when the load repeat count is accumulated a lot.

However, in the case of the bolt coupling (A1) using the structural screw fixing agent of the present invention, even after the initial stress relaxation occurs, even if the load repetition frequency increases, the stress state does not change, it is possible to prevent the bolt loosening semi-permanently.

Fig. 15 is a graph of the horizontal vibration test results shown in Figs. 12, 13A, and 13B.

Referring to FIG. 15, there was almost no bolt tension loss when the screw fixing agent was applied (B1, B2, B3). However, when no thread fixant was applied (B4), tension loss occurred after a few seconds, and after 2 minutes, bolt loosening occurred and most of the tension was lost.

In addition, in the case of applying the screw fixing agent (B1, B2, B3), even when only the tension of 11,300kgf, which is 50% of the standard bolt tension of 22,600kgf, was not lost, the bolt tension was lost. It can be judged that bolt loosening does not occur even if tension introduction is insufficient or tension loss is large up to 50% during common use.

Figure 16 shows a state of fastening the bolt using the torque wrench 75 to test the performance of the bolt loosening prevention method of the steel structure using the structural screw fixing agent according to the present invention.

When the bolt is fastened using the structural screw fastener according to the present invention, the screw fastener performs a kind of lubrication action, so that the friction caused by residues on the threaded surface of the bolt and the nut can be reduced, and thus the target screw is tightened. Tension can be easily introduced into the bolt. After preparing a bolt to which the screw fixing agent is applied and a bolt to which the screw fixing agent is not applied, tightening the bolt using the torque wrench 75 of FIG. 16 may measure the torque introduced to the bolt.

17 is a graph showing the relationship between the tightening torque of the steel bolt and the introduction tension in the bolt loosening prevention method of the steel structure using the structural screw fixing agent according to the present invention.

Screw fixing agent is more lubricity than Class A high tensile bolts (lubricated by oil on nut thread), which are mainly used in high tensile bolt friction joints.The screw fixing agent has a torque factor of 0.11 to 0.15. Has a low torque coefficient of 0.10 to 0.12, so the torque loss is small when the design bolt tension is introduced. In particular, since the torque coefficient is narrow, the design bolt tension is always introduced when several bolts are tightened to ensure reliability. can do.

By lowering the torque coefficient in this way, it is possible to avoid the stress concentration occurring at a specific part of the connecting member as uniform tension can be introduced into the entire bolt group.

When the screw fixing agent is applied, friction is reduced in the thread of the bolted portion by self lubrication, and thus has a low torque coefficient value, whereby the tightening torque for introducing the design bolt tension is small. On the other hand, the breakaway torque when unscrewing the fastened bolts after hardening of the screw fixing agent is relatively large due to the addition of the adhesive strength of the screw fixing agent. This has the effect of suppressing the bolt loosening to some extent but is incomparably small compared with the bolt loosening inhibiting effect by the tension of the bolt itself.

In addition, when the thread fixing agent is applied, a prevailling torque occurs, which is caused by the filling of the thread fixing agent in the gap between the bolt and the nut thread. Refers to the resistance that the government does not easily loosen, and this loosening torque allows the screw to be released only after the first nut has returned. These loosening torques are critical to ensuring the safety of steel structures, which are not expected in general mechanical fixing methods (spring washers, etc.) and occur only when thread fixing agents are applied.

18 is a graph showing the result of the tension retention performance test of the bolt connection portion fastened according to the present invention. According to Fig. 18, it can be seen that the tension of the bolt is almost not lost even after applying 3 million times or more of load.

19 is a graph of the results of the high temperature strength test of the bolted connection portion fastened according to the present invention, and FIG. 20 is a graph of the results of the temperature shock test.

As shown in FIG. 19, even when exposed to a temperature up to about 40 ° C, the breaking torque was almost maintained as in the initial state. As shown in FIG. 20, the breakdown torque was maintained at -40 ° C to 120 ° C. Even after prolonged exposure, the breaking torque was maintained at 60% or more of the initial time.

Fig. 21A shows a test piece for fatigue test manufactured to test the effect of the bolt loosening prevention method of a steel structure using the structural screw fixing agent according to the present invention.

The fatigue test specimen in Fig. 21A places the joint plates 71, 72 up and down at the connection points of the base materials 70, and bolts 5 into the bolt holes 71a perforated in the joint plates 71, 72. Insert and tighten.

FIG. 21B shows the process of applying the threadlocker to the fatigue test specimen of FIG. 21A, and FIG. 21C shows the finished specimen as a result.

22 is a graph showing the results of a static test on the load-displacement relationship between the bolt connection portion C2 to which the structural screw fixing agent according to the present invention and the bolt connection portion C1 to which the screw fixing agent is not applied. As shown in the graph, it was confirmed that the case of introducing the screw fixer of the present invention (C2) is less than 60% less displacement for the same load compared to the case of not introducing the screw fixer (C1).

The bolt loosening prevention method of the steel structure using the structural screw fixing agent according to the present invention can be obtained in a strong adhesive force with a single adhesive injection, especially by applying to steel structures of civil engineering and construction where safety is important, safety of steel structure It can be improved, easy to maintain after construction, and the cost of safety inspection can be reduced.

Claims (4)

In the method of joining the steel structure constituting the civil structure or building structure, Forming a plurality of bolt holes in the base material of the steel structure; Forming a plurality of bolt holes in the joint plates to be attached to the front and rear surfaces of the base material; Positioning the joint plates on the front and rear surfaces of the base material and matching the bolt holes with each other; Inserting a plurality of bolts into the bolt holes, respectively; Applying a liquid or solid threadlocker to the threads of the bolts; And Fastening a nut to each of the bolts and tightening to introduce a predetermined tension between the bolt and the nut; Bolt loosening prevention method of the steel structure using a structural screw fixing agent comprising a. In the method of joining the steel structure constituting the civil structure or building structure, Forming a plurality of bolt holes in the base material of the steel structure; Forming a plurality of bolt holes in the joint plates to be attached to the front and rear surfaces of the base material; Positioning the joint plates on the front and rear surfaces of the base material and matching the bolt holes with each other; Inserting a plurality of bolts into the bolt holes, respectively; Applying a liquid or solid screwlock to the threads of the nuts to be fastened to the bolts; And And fastening the nuts to the bolts and tightening a predetermined tension between the bolts and the nuts, respectively. 2. In the maintenance method of the steel structure constituting the existing civil structure or building structure, Structural b characterized in that the screw fixing agent penetrates the liquid screw fixing agent into the bolt and nut fastening portion installed in the joint plate connecting the base materials of the steel structure to the fastening portion of the bolt and nut. Bolt loosening prevention method of steel structure using accident refining. The method of claim 1, wherein the screw fixing agent comprises a dimethacrylate ester. 4.

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