High -strength bolt connection is one of the most connected forms in the steel structure engineering.
The quality of the high -strength bolt quality directly affects the stability and safety of the entire steel structure. Therefore, the current \” Steel structure engineering construction quality acceptance specification (GB50205-2001) \”(hereinafter referred to as the\” Specification \”) and the 1995 version of the specifications are controlled by high-strength bolts as a sub-project. During the implementation process, there are two main cases. First, most of the steel structure manufacturing and installation units, and even quality inspection and supervision departments mix high -strength bolt connecting surfaces with design requirements.
Two 2 It is the operation of the \”Specification\” for the quality requirements of the friction surface, and the operation of the inspection personnel is inconvenient.
This article discusses the flatness requirements of the friction surface for these two issues.
1 The concept of frictional surface of the friction surface and the top tight contact surface,
In the steel structure engineering, the connection of the pillar beam, as well as the limitation of the component transportation and hanging size, and the beam on -site connection. Use friction -type high -intensity bolt connection in many places.
This connection rely on the pre -tightening force of the bolt to cause the two connection surfaces to cause pressure. Under the action of this pressure, when the beam pillar is loaded, the two connections are connected Noodles will produce a quiet friction to offset the weight and load of the beam pillar. At this time, the bolt should not be cut.
The static friction force and the pre -tightening force of the bolt, the flatness and roughness of the connecting surface, the connection surface, and the roughness of the roughness of the connection surface The size is related. The pre -tightening force is determined according to the diameter and intensity level of the bolt. The roughness of the connection surface determines the friction coefficient, that is, the anti -slip coefficient. The test parts of the same face are confirmed by the test.
The only uncertain factor is the flatness of the friction surface.
The difference between the friction surface and the tight contact surface.
The tight contact surface refers to the contact surface that requires the polishing top in the steel structure installation project. The typical situation of the steel structure installation is: the steel crane beam and the pillar shoulder or the column should beam or the columns of the bald support plate at the end. The contact surface between the beef legs; the node between the hinge of the steel house and the node between the trustees, etc.
The installation requirements of the tight contact surface are high, and the area of \u200b\u200bmore than 75%is close to The area should be less than 25%. Therefore, the top contact surface should be polished.
The friction surface generally exists at the end of the longer component. 123] Therefore, the quality standards of the friction surface and the tight contact surface should be treated differently, and the requirements of the surface of the surface should not be mixed. , Welding splash, welding scars, iron oxide skin, dirt, etc., except design requirements should not be painted.
Check Quantity: All inspections.
Inspection method: Observe and check.
In the specification of the 1995 version, there are \”flat\” requirements for frictional surfaces, and the current \”Specification\” General Delete the word \”flat\”.
There is no requirements for the flatness of the frictional surface, which is not conducive to mastering during actual inspection.
2 frictional surface requirements .
Because the welding of the friction surface plate and the steel beam and the welding of various pressure plates will cause end plate welding deformation.
If the number of bolts of the juice is large, on the end plate, it is on the end plate. The layout is more uniform. When pre -tightening the bolt will be forcibly tied to the deformation end plate, but in fact, at this time, the pre -tightening force of the bolt is lost on the deformation of the end plate. , Reduced the static friction.
After the component is connected, this defect is difficult to test.
Therefore, the friction surface should be tested before the connection.
The friction surface should be flattened. The importance of degree.
For the connected surface gaps caused by the thickness tolerance of the steel plate, the manufacturing deviation, or the installation deviation, the \”Specification\” proposes the treatment method. Eliminate the thick plate into a gentle slope. When it is greater than 3.0, add the pad.
In fact, this processing method is only applicable to the bolt connection of the flat connection, and the universal application docking connection, especially the large plane, especially the large plane The end board, this method is difficult to apply.
So proposing a amount of a amount of amount of frictional surface connection is particularly important.
The relationship between the friction surface and the anti -slip coefficient is high intensity The design basis for the bolt connection is the anti -slip coefficient of the friction surface, that is, the method of friction to verify the \”: In order to make the steel structure meet the design requirements, the actual condition after the friction surface connection should be consistent with the test parts, but in fact After welding, the component is deformation, and its flatness cannot be exactly the same as the test parts.
Although the processing method of the actual surface friction surface is the same as the test parts, the anti -slip coefficient of the component is usually compared to the test obtained from the test. The coefficient of the coefficient is low.
Therefore, it is more important to propose a easy -to -operate end plate flatness testing method and quality requirements.
After the high -strength bolt friction connection, the bolt pre -tightening is pre -tightened Under the action of force,
23. The two friction end plates generate pressure. When the component is loaded, the static rubbing force of the friction surface will be produced. The area of \u200b\u200bthe sticker and the pre -tightening force of the bolt is proportional.
The pre -tightening force is not changed according to the specifications of the bolt. What is discussed is the tight area of \u200b\u200bthe end plate junction surface.
① Due to due to it The thickness of the end plate is limited, so under the influence of the bolts, the pressure between the end plate is inconsistent. ——The pressure within the fixed range, and the pressure away from the bolt part will gradually decrease, so it can be considered that the Deng Jie area within a certain range centered on the bolt can completely play a anti -slip effect; ② in the anti -slip anti -slip In the migration test, the anti -slip coefficient is calculated by the measured sliding load, the number of friction noodles, and the total pre -tightening force of the bolt.
In the case of the total pre -tightening force, the trial is changed The width size of the piece will affect the sliding load, but this impact will not be large (Table 1).
Table 1 10.9 M16 high -strength bolt Bid -to -slip test data board width (MM) pre -tightening (KN) Sliding load (KN) Sliding coefficient Flating requirements and testing methods.
① According to different bolt diameter resistance slippage test board width plus 10%magnifying coefficients As a diameter that uses the bolt as the center of the center … It is required to be close to the two friction surfaces in this range, and the unevenness of the remaining parts is less than 2mm. The degree requirement is within 0.20mm), leaning on the friction surface of the end plate in different directions, and requiring that the segicals that are 0.3mm in the circle cannot be plugged in, and the segicals of 1.8 in the non -tight circle cannot be plugged in. [ 123]
The endboard must be tied to the end plate.
3 Conclusion. According to the \”Specification\” and the relevant instructions, the friction surface and the design top contact surface are distinguished to facilitate the actual situation on the actual situation. In the inspection, the corresponding inspection requirements are selected.
The requirements for the flatness of the friction surface make the actual friction surface connection closer to the anti -slip test parts to ensure the quality of the project.
[ 123] The inspection requirements data proposed in the article can be continuously improved in actual engineering operations to make it more reasonable.
This can also avoid the phenomenon of the tightness of the friction surface one -sided, which causes the bolt to be super twisted.