Fatigue test device and method for externally prestressed reinforced concrete beams

Abstract

The invention provides an external prestressed concrete beam fatigue test device and method, which belong to the technical field of indoor dynamic load test of bridge engineering concrete beam structure. The positioning board and the limit beam; two sets of rigid frames are relatively fixed on the rigid base; the positioning board is fixed between the two sets of rigid frames, and the positioning board is provided with multiple sets of positioning jacks, and each set of positioning jacks includes The middle hole and the lateral hole; the limit beam includes two sets of limit plates set opposite to each other, a fixed rod connecting the two sets of limit plates, and an anti-friction wheel rotatably installed at the ends of the two sets of limit plates; The inserting plate passes through the lateral hole; the fixing rod passes through the middle hole, and self-locking nuts are threaded on the rod body on both sides of the middle hole; the anti-friction wheel faces the longitudinal section of the bent concrete beam. The invention can effectively limit the lateral stability of the flexural concrete main girder in the cyclic loading process of the fatigue test.

Description

technical field [0001] The invention belongs to the technical field of indoor dynamic load testing of concrete beam structures in bridge engineering, and specifically discloses an external prestressed concrete beam fatigue test device and method. Background technique [0002] Prestressed concrete beams and external prestressed concrete beams are widely used in engineering structures such as small and medium-span bridges. Such engineering structures are susceptible to repeated fatigue loads from vehicles during their normal service life, resulting in cumulative fatigue damage and seriously affecting the safety of the structure. sex. In addition, since there is no mature theoretical model to study the fatigue performance of reinforced concrete beams strengthened by external prestressing, the cumulative fatigue damage test of concrete beams is generally studied in the laboratory. However, existing fatigue tests on beams with small cross-sectional dimensions and large height-to...

AI Technical Summary

Problems solved by technology

[0002] Prestressed concrete beams and externally prestressed concrete beams are widely used in engineering structures such as small and medium-span bridges. Such engineering structures are susceptible to repeated fatigue loads from vehicles during their normal service life, resulting in cumulative fatigue damage and seriously affecting the safety of the structure. sex

In addition, since there is no mature theoretical model to study the fatigue performance of reinforced concrete beams strengthened by external prestressing, the cumulative fatigue damage test of concrete beams is generally carried out in the laboratory.

However, existing fatigue tests for beams with small cross-sectional dimensions and large height-to-width ratios are prone to lateral deflection under repeated loads, which seriously affects the safety of the structure.

Secondly, during the fatigue test, in order to effectively protect the displacement gauge from damage during the reciprocating cyclic loading process, it is necessary to separate the displacement gauge from the beam body during the fatigue test loading process, and after the corresponding fatigue loading times, the static load is repeated Keep the original position of the displacement gauge unchanged during the process to ensure the consistency of the displacement test. The existing device cannot achieve the above effect

Third, the existing external prestressed steering device cannot effectively transmit the force on the left and right sides of the steel strand. Under the action of cyclic fatigue load, the external prestressed steel cable is prone to cumulative fatigue damage.

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