Research On Seismic Test Method Based On Electro-hydraulic Servo Top Excitation

The research on the seismic performance of building structure has always been the focus of scholars at home and abroad,and the seismic test of structure is the most direct and effective method to understand its seismic performance.The in-situ dynamic test is usually used to study the seismic performance of existing building structures such as threedimensional garage,large steel structure,reinforced concrete frame structure and masonry structure.Compared with the traditional pseudo static test,simulated earthquake shaking table test and pseudo dynamic test,the in-situ dynamic test has the advantages of no need to scale the structure and correct boundary conditions.Using electro-hydraulic servo excitation equipment to carry out in-situ dynamic test on the structure is a more effective means of seismic performance test.In this paper,combined with three traditional seismic test methods,through theoretical analysis,programming development and experimental research,the seismic test method based on Electro-hydraulic Servo top excitation is studied:（1）The seismic test method based on sine wave excitation is studied.The test method is that the electro-hydraulic servo vibration exciter is installed on the top floor of the structure.Through the electro-hydraulic servo vibration exciter,the freely moving mass block is driven to do simple harmonic motion with specified frequency and amplitude.The inertia force generated by the mass block motion acts on the structure as the excitation force,making the structure produce equivalent seismic response.Based on the principle of equivalent base shear force,the expression of excitation force required in sine wave excitation test is derived.Based on the simple harmonic motion equation of the particle and the principle of energy equivalence,the value method of excitation parameters is derived.Through the field test and parameter verification of sine wave excitation test method,the dynamic relationship between excitation force and mass block quality,movement frequency and motion amplitude is verified,which ensures the correctness of command output,and lays a foundation for further research.（2）The seismic test method of structure based on the excitation of the top broadband is studied.The test method is to convert the seismic wave signal into the top broadband excitation signal through theoretical derivation,and then input the signal into the electrohydraulic servo vibration exciter on the top of the structure to excite the structure,so that the response of the structure under the action of the top excitation signal is close to the response of the structure under the action of earthquake.The feasibility of the method in theory is verified by an example.A standardized application program is developed by using VB6.0 and Matrix VB plug-in,which lays a foundation for the subsequent application of this method in practice.（3）By designing a two-layer full-scale UHPC module composite structure,the pseudo dynamic test,modal test and sine wave excitation test are completed.Through the pseudo dynamic test,the displacement response,interlayer displacement angle,hysteretic curve and strain response of the structure under seismic load are obtained.Combined with the test results,the seismic performance of the structure is evaluated.The modal parameters of the structure are obtained through the modal test,which lays the foundation for the sine wave excitation test.Based on the sine wave excitation test method proposed above,the electrohydraulic servo vibration exciter is placed on the top of the structure,and the sine wave excitation test is carried out on the structure to obtain the dynamic response of the structure.The feasibility and effectiveness of the method are verified by comparing with the phenomenon and results of pseudo dynamic test.