| The prefabricated segmental bridge column has good self-centering performance and extreme displacement capability,but the damage mechanism under earthquake is still unclear,and the traditional damage evaluation method cannot accurately describe seismic damage of the prefabricated segmental column,how to accurately evaluate The damaged state is an important issue in the seismic performance study of prefabricated segmental bridge columns.In order to obtain seismic damage models based on prefabricated segmental bridge damage,the seismic performance and damage mechanism is analyzed,and the seismic damage model considering the self-centering performance of the column is proposed.This paper performs three-dimensional solid finite element modeling for prefabricated segmental bridge columns,compared the development characteristics of performance level and material damage under the seismic action of columns with different design parameters.Subsequently,the self-centering performance characterization method was studied and simplified from the reset performance characterization method from the prefabricated segmental bridge column.The self-centering correction factor is proposed to describe the energy consumption damage of the column under seismic action to obtain a seismic damage assessment model for self-centering performance.The main research work in this article is as follows:(1)The prefabricated segmental bridge column is subjected to a finite element modeling and the model is verified,and the testing model can predict the mechanical behavior under the circular loading of the column.The columns of 5 groups were set for seismic performance analysis and parameter sensitivity research,and analyzed each bridge column damage,comparing different design parameters on the damage mechanism of column,based on the parameter optimization design proposal based on seismic performance.(2)Analysis of the damage mechanism of the prefabricated segmental bridge column based on the damage development process in the test and numerical results.Referring to the existing characterization methods of prefabricated segmental bridge column of self-centering performance parameters,the self-centering coefficient representative of the moment contribution ratio is used,and the simplified calculation method has been studied based on the cross-sectional state analysis.The self-centering performance of 23 different bridge column limits is characterized by simplified calculation methods.(3)In the shortcomings of the seismic damage evaluation method of the reinforced concrete structure,this paper is improved on the basis of the Park-Ang double-parameter seismic damage model,considering the relationship between self-centering performance and energy consumption damage of prefabricated segmental bridge columns.Through MATLAB statistical analysis,the limit state damage indicator value of 23 test pieces and the quantitative relationship of the self-centering coefficient,proposes that the seismic energy damage of the bridge column is proposed to obtain a seismic damage model suitable for prefabricated segmental bridge columns.Further,considering the Component degradation and the partial damage of the column material of the loading process,The relationship between the damage state of bridge piers and the change of characteristic indexes of components and materials is studied.The boundary index between the damage development states is determined and the cross-scale damage classification of prefabricated segmental bridge columns is proposed.The main conclusions are as follows:(1)The main impact of design parameters on the seismic performance and damage mechanism of prefabricated segmental bridges include: Increasing energy-consuming steel non-bonded lengths can protect the energy consumption steel bars but break early,excessive non-bonded length Limit the energy consumption capacity of the column.Increase the energy consumption rate of the energy consumption can significantly increase the energy consumption capacity of the bridge column,but will affect the self-centering ability of the bridge.Too low initial prestressing force level may lead to slip shear failure between segments.The ultimate displacement capacity of bridge piers using ordinary high-strength concrete decreases obviously,but the energy dissipation capacity is stronger under the same displacement amplitude.(2)The self-centering coefficient based on the contribution rate of bending moment in the ultimate state can characterize the self-centering performance of bridge columns.The simplified calculation method of the self-centering coefficient is suitable for the case of known loading and material deformation.And the calculation method after the simplification The parsing method error is within an acceptable range.(3)There is a linear relationship between the hysteretic dissipation damage and the self-reduction performance of Prefabricated segmental bridge columns.The seismic damage model considering of self-centering performance has certain physical significance.The boundary state damage indexes of each damage grade are also consistent with the damage development phenomenon.It can be used to quantitatively evaluate the seismic performance level under the seismic action in the full life cycle analysis of the prefabricated segmental bridge column. |
