Device and method for testing amount of looseness of connecting pretightening force of after-fire high-strength bolt

A technology of high-strength bolts and measuring devices, which can be used to measure the direction of torque/torsion during tightening, which can solve problems such as axial force meter measurement, and achieve the effects of avoiding waste, convenient operation and reasonable design.

Inactive Publication Date: 2014-05-07
CHANGAN UNIV
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

However, the loss of pretightening force of high-strength bolt conne

Method used

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  • Device and method for testing amount of looseness of connecting pretightening force of after-fire high-strength bolt
  • Device and method for testing amount of looseness of connecting pretightening force of after-fire high-strength bolt
  • Device and method for testing amount of looseness of connecting pretightening force of after-fire high-strength bolt

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Embodiment Construction

[0052] Such as figure 1 As shown, the high-strength bolt connection pretightening force slack measuring device after a fire of the present invention includes a strain tester 1, a computer 2 connected with the strain tester 1, a base 3 for fixing the bolt 7 to be tested and a bearing for bearing The bolt axial force receiving device for receiving the axial force of the test bolt 7, and the torque loading device 10 for applying torque to the bolt pair composed of the bolt 7 to be tested, the nut 11, the upper gasket 15 and the lower gasket 16; The base 3 is provided with a hole for engaging and connecting the bolt heads of the bolts 7 to be tested, and the bolt axial force bearing device is arranged in sequence from bottom to top and the bottom for the bolts to be tested 7 to pass through in sequence from bottom to top. Rigid backing plate 4, elastic steel sleeve 5 and upper rigid backing plate 6 are made up of, and described nut 11 is threadedly connected on one end of to-be-te...

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Abstract

The invention discloses a device and method for testing the amount of looseness of connecting pretightening force of an after-fire high-strength bolt. The device comprises a strain tester, a computer, a base, a bolt axial-force bearing device and a torque loading device. The bolt axial-force bearing device is composed of a lower rigid cushion plate, an elastic steel sleeve and an upper rigid cushion plate, wherein the lower rigid cushion plate, the elastic steel sleeve and the upper rigid cushion plate are sequentially arranged from bottom to top, the bolt to be tested can penetrate through the lower rigid cushion plate, the elastic steel sleeve and the upper rigid cushion plate from bottom to top in sequence, a nut is connected to the end, penetrating through the upper rigid cushion plate, of the bolt to be tested in a threaded mode, and a first resistance strain gage and a second resistance strain gage are symmetrically bonded to the outer wall of the elastic steel sleeve. The method includes the following steps that firstly, the looseness state of the bolt, having suffered from fire, to be tested is marked; secondly, the torque coefficient of the bolt, having undergone a fire suffering test, to be tested; thirdly, the amount of looseness of connecting pretightening force of the bolt, having undergone the fire suffering test, to be tested is calculated. The device and method are high in testing precision, testing results can provide reference for after-fire safety performance assessment and reinforcement treatment of a steel structure, waste is avoided, potentially safety hazards are reduced, and the practicability is strong.

Description

technical field [0001] The invention belongs to the technical field of high-strength bolt connection performance research, and in particular relates to a device and method for measuring the pretightening force relaxation of high-strength bolt connections after a fire. Background technique [0002] High-strength bolt connection has become an important form of modern steel structure connection due to its simple structure, convenient construction, high bearing capacity, and easy disassembly. It is widely used in industrial and civil buildings, bridge engineering, water conservancy and hydropower projects, etc. Different from ordinary bolts, the working principle of high-strength bolts is to fasten the connected plates together by applying a designed pre-tension force to the connecting pair, with high connection rigidity and high bearing capacity. The pre-tension force plays a fastening role on the bolt pair, usually called pre-tightening force, and its magnitude will affect the...

Claims

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Application Information

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IPC IPC(8): G01L5/24
Inventor 陈建锋周天华
Owner CHANGAN UNIV
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