Study On Simulation Method Of Substructure Boundary Conditions For Seismic Hybrid Test Of Frame Structures

The substructure hybrid seismic testing method,as an effective research method,can reflect the seismic performance of the structure.Combining numerical simulation with experimental testing,it can well reproduce the response of large complex structures under seismic excitation.The current seismic scholars devoted themselves to the loading design of experimental substructures and the calculation of numerical substructures.Among them,the accurate simulation of complex substructural boundary conditions is the key to ensure the feasibility and accuracy of the hybrid testing,and it is still a difficult problem to satisfy the balance and coordination between substructures.In this paper,theoretical and experimental research were carried out on this issue.The main contents are as follows:(1)A simulation method for complex boundary conditions was proposed.Using the method of reducing the degree of freedom of test unit boundary,cooperative loading can be achieved by transferring the loading interface to a relatively simple place for structural internal force analysis by expanding the test unit.The inflection point property was used to realize the simulation of the rotational freedom of the test unit,the overlapping domain was used to consider the interaction between the components,the substructure boundary condition simulation scheme has been determined.Finally,the degree of freedom of the experimental substructure was simplified from nine to two.(2)Shaking table test was carried out on a three-storey,three-span,two-pole steel frame structure as a whole structure,it can effectively reflect the seismic performance of the structure.Shaking table test for small model steel frame structure was used to analyze the spatial performance of structure in all directions from displacement response,acceleration response,strain response and hysteresis performance,which can lay a foundation for further study on the correctness of the boundary condition simulation method by hybrid seismic test.(3)The substructure hybrid seismic test was carried out on a one-storey,half-high and one-span,half-wide structure.The hybrid test system was constructed,the substructure boundary condition simplification scheme was established.Through the comparison of the structural displacement response between the substructure hybrid seismic test and the shaking table test,which proved the correctness and feasibility of the proposed boundary condition simulation method.(4)The shaking table test of the small model structure parameters for the incomplete scale structure was designed.Designed the structure based on its natural frequency,the modal parameters were basically met with the similarity ratio requirements by compressing the seismic wave time and increasing the counter weights.From the aspects of structural dynamic characteristics and seismic performance analysis,compared test results with the time history analysis of self-made MATLAB program.It can not only verified the rationality and accuracy of the parameter design,but also proved that the feasibility of the self-programming.