Equipment and method for eccentric pull-out test of frp bars considering the influence of bending-shear stress

Abstract

The invention discloses an FRP (fiber reinforced plastic) rebar eccentric pull-out test device considering a bending shear stress effect. The device comprises an outer frame, wherein a concrete block is arranged in the outer frame; an FRP rebar is penetrated through the concrete block from top to bottom, a free end displacement meter is connected to the upper end of the FRP rebar; a universal test machine platform is connected below a bottom plate of the outer frame through multiple screw rods; the universal test machine platform is provided with a pull-out force test load sensor; the lower end of the FRP rebar is clamped by a universal test machine clamping head after penetrating through the pull-out force test load sensor; the universal test machine clamping head is connected with a loading end displacement meter; a bracket is arranged at one side of the outer frame; a lifting jack is arranged on the bracket; a piston rod of the lifting jack is connected with a load sensor for testing a horizontal force through a connecting screw rod; the load sensor for testing a horizontal force is connected with a loading rod; the loading rod is connected with a side surface of the concrete block; and the other side of the concrete block is connected with the outer frame. According to the invention, the stress of the FRP rebar in the test process is identical to the stress of the FRP rebar in practical engineering.

Description

technical field [0001] The invention relates to the technical field of pull-out test for building reinforcement, in particular to an FRP tendon eccentric pull-out test device and method considering the influence of bending and shear stress. Background technique [0002] In a highly corrosive environment, the use of fiber reinforced composite bars (FRP bars) to replace traditional corrosion-prone steel bars will greatly improve the durability of concrete structures and prolong the service life of concrete structures, thereby minimizing the cost of the entire life cycle of the structure. change. The effective bonding between FRP bars and concrete is the key factor to ensure that they work with concrete and work together. The surface morphology of FRP bars is different from ordinary steel bars, and the bonding performance between them and concrete requires a lot of theoretical and experimental research. [0003] At present, the most commonly used test method for the bond perf...

AI Technical Summary

Problems solved by technology

However, the loading device of the beam-type pull-out test is complicated, the preparation of the specimen is complicated, and the test efficiency is not high

Moreover, during the bending process of the beam, there is a rotation between the loading end and the free end of the FRP tendon, which seriously affects the accurate measurement of the slip value.

In addition, the pull-out force of the reinforcement needs to be obtained through a conversion formula, which is not intuitive and accurate enough

Moreover, since a steel strand needs to be built into the pure bending end, when the test studies the bond durability between the FRP bar and the concrete interface, and the specimen needs to be placed in an accelerated corrosion environment, the anti-corrosion treatment of the steel strand is also a difficult problem

[0005] It can be seen from the above that in the study of the bonding performance of FRP bars and concrete, there are many practical problems in the existing test methods, which hinder the research on the bonding properties of FRP bars and concrete.

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