Specimen end clipping reinforcement method during FRP rib stress relaxation characteristics test

Abstract

The invention provides a method for reinforcing and gripping at an end part of a test piece during stress relaxation test of an FRP rib. A gradient transition section is arranged at a reinforcing section at the end part of the test piece, and an external thread arranged at the reinforcing section is matched with a screw thread of a metal splint with an internal thread to eliminate sliding and creeping of a gripping area at the end part during experiment. The method is specifically realized by the following steps: intertwining a section of fiber cloth soaked by resin and being capable of realizing gradient transition at the end part of the test piece, winding the external thread at the glass fabric intertwined section by a thin fiber strand according to a predetermined thread pitch before resin solidification, matching the external thread with the internal thread of the metal splint, and buckling two prefabricated metal splints coated with release agent to the wound screw thread to be fixed. The method solves the problem that sliding, creeping and the like in the gripping area at the end part of the test piece influence the test results when the FRP rib is subjected to stress relaxation test, and the metal splints can be repeatedly utilized.

Description

technical field [0001] The invention belongs to the field of composite material structure and mechanical performance testing, and relates to a method for reinforcing anchor clips at the end of a test piece. Background technique [0002] Cracks or micro-cracks will appear in the traditional reinforced concrete structure during use. When encountering sea water or salty snow water (sprinkling salt to form salty snow water for melting snow) or corrosive gas liquid, the steel bar will be corroded. , resulting in the decline or complete loss of the structural bearing capacity; when there is a high-frequency electromagnetic field around, the steel bars will generate heat due to the dual current effect, resulting in thermal stress and cracking of the concrete; widely used in water conservancy and hydropower projects, deep foundations, underground structures , slope stability, mine roadway support, etc. may be corroded due to the interaction with groundwater and the chemical composit...

AI Technical Summary

Problems solved by technology

[0005] In the literature, there is no mature plan for the clamping and strengthening methods of the end of the specimen for the test of the stress relaxation characteristics of FRP tendons. It is difficult to eliminate the slippage of the anchorage with the clip-type anchorage. Correction by compensation will inevitably introduce system errors, and multiple compensations often lead to early failure of the specimen; it is difficult to eliminate the creep effect of the adhesive with adhesive anchorage, and the adaptability to the testing machine is poor; therefore, a new It is very necessary to have a more efficient method of specimen preparation

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