Fatigue test device and method for external prestressing reinforced concrete beam

Abstract

The invention provides a fatigue test device and method for an external prestressing reinforced concrete beam, and belongs to the technical field of bridge engineering concrete beam structure indoor dynamic load tests. The device comprises a transverse limit assembly; the transverse limiting assembly comprises a rigid base, rigid frames, a positioning insertion plate and a limiting beam; the two groups of rigid frames are oppositely fixed on the rigid base; the positioning insertion plate is fixed between the two rigid frames, a plurality of groups of positioning insertion holes are formed in the positioning insertion plate, and each group of positioning insertion holes comprises a middle hole and a lateral hole; the limiting beam comprises two groups of limiting insertion plates which are oppositely arranged, a fixing rod for connecting the two groups of limiting insertion plates, and anti-friction wheels which are rotationally mounted at the end parts of the two groups of limiting insertion plates; the limiting insertion plates penetrate through the lateral holes; the fixing rode penetrate through the middle holes, and self-locking nuts are arranged on the rod bodies on the two sides of the middle holes in a threaded fit mode; and the anti-friction wheels face the longitudinal section of a bent concrete beam. According to the invention, the lateral stability of the bent concrete main beam in the cyclic loading process of the fatigue test can be effectively limited.

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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