Pseudo-static testing device for concrete columns after non-peripheral fire exposure and implementation method thereof

Abstract

The invention provides a pseudo-static testing device for concrete columns after non-peripheral fire exposure and an implementation method thereof. According to the fire exposure of a concrete column, two movable stove walls plus a temporary filling wall built in the middle opening are combined to form a fourth stove wall of a stove of the testing device. The stove is arranged in the body of a reaction frame, and a vertical load application unit is mounted on the bottom of a middle horizontal steel beam to apply vertical load on the concrete column; and a horizontal tension-compression servo loading unit is mounted on a horizontal reaction wall, and can apply pushover load and low-cycle horizontal reversed load on the concrete column specimen. The testing device first carries out a fire test under non-peripheral fire exposure on a loaded concrete column, and then carries out a pseudo-static test after fire extinguishment and cooling, and a data acquisition system is used for acquiring air pressure, temperature, displacement and load at each measuring point. The invention is applicable to the experimental study on the fire resistance and post-fire anti-seismic performance of concrete columns under non-peripheral (such as three-side, two-neighboring-sides and single-side) fire exposure.

Description

technical field [0001] The invention relates to the technical field of damage assessment of concrete structures after fire, in particular to a quasi-static test device and its implementation method that can consider various non-surrounding concrete columns after fire. Background technique [0002] Although the fire and high temperature will cause different degrees of damage to the mechanical properties of steel bars and concrete and the bonding and anchoring properties of the two, most reinforced concrete structures can still be used normally after damage assessment, reinforcement and repair, thereby exerting huge economic benefits. It is of great significance to scientifically and accurately evaluate the residual mechanical properties of reinforced concrete structures after fires, and to formulate repair and reinforcement plans for damaged structures to ensure the safety, applicability and durability of repaired structures after fires. . [0003] At present, some achieveme...

AI Technical Summary

Problems solved by technology

However, there are few experimental research results on the shear bearing capacity and seismic performance of concrete columns after different fire exposure methods.

[0004]The existing post-fire concrete column quasi-static test device and implementation method generally have the following problems: (1) It is difficult for the test device to test the non-fired concrete column The existing quasi-static test results of concrete columns are all based on the situation after the surrounding fire, and there is no report on the research results of the quasi-static test of concrete columns after different fire methods

In order to investigate the influence of different fire exposure methods at high temperature, the existing limited tests use several layers of fireproof cotton on the surface of the test piece and put it into the furnace to conduct fire tests according to the fire exposure method in four directions to approximate the unfired surface. The ambient temperature and thermal boundary conditions of the unfired surface are quite different from those in the real fire test

(2) Existing post-fire residual load bearing performance test of concrete column members, usually unloaded at high temperature or sustained load at high temperature but unloaded after extinguishing the flame, and after the specimen is cooled to normal temperature, it is lifted out of the furnace and then the load bearing performance after fire is carried out In the test, there is a problem of discontinuity in the sustained load of the specimen during the whole process of heating and cooling and in the post-disaster bearing performance test

(3) There is no reaction wall with sufficient rigidity around the existing fire resistance test device. Therefore, it is impossible to install a horizontal tension-compression servo loading device, and to directly conduct pseudo-static tests on the concrete columns after fire. After the parts are hoisted, they are transported to the anti-seismic laboratory for quasi-static test

However, the furnace height of the common vertical component fire resistance test furnace is 3000mm, which is not suitable for the fire test of the test piece of the quasi-static test.

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