Research On Seismic Performance Analysis Of Precast Segment Concrete Hollow Columns

With the advancement of the national urbanization and the implementation of the sustainable development strategy,the state has raised higher requirements for the high efficiency and ecological development of the bridge structure.Due to the backwardness,the traditional cast-in-place form of construction work of concrete bridge columns cannot meet the requirements of the bridge construction cycle,and under the strong earthquake,larger residual displacement may occur and is difficult to repair.The segmental bridge column,as a new type of column that was only promoted and used at the end of the last century,is in the initial stage of research and engineering application in China.Compared with the cast-in-place concrete column,it is featured by small residual displacement and weak energy-dissipating capacity.It is of obviously economic and social significance to replace the traditional cast-in-place concrete columns with segmental bridge columns,reduce the residual displacement of the columns under the seismic action,and make the columns easier to repair.Based on the Open Sees numerical simulation analysis platform,with a set of typical segmental hollow bridge column specimens as the research objects,this paper proposes a numerical analysis model that can accurately analyze the seismic performance of segmental bridge columns,and performs analysis and summary of the seismic response characteristics of segmental bridge columns under the earthquake action using the new model.The main research contents and contributions of this paper are as follows:(1)It systematically generalizes the development process of segmental bridge columns,and summarizes the advantages and disadvantages of using fiber model method to analyze the seismic performance of segmental bridge columns.(2)Based on the Open Sees numerical simulation analysis platform,the original segmental bridge column fiber model method is simulated and improved,and the multi-spring truss model at the bottom of the column is constructed to replace the method of using the fiber unit with Concrete01 simulating joint in the original fiber model method.The problem of divergence in the calculation of the fiber model of the original segmental bridge columns is improved,and the problem of poor goodness of fit after comparison of the calculation result of the original simulation method with the experimental result is solved.The improved model can accurately simulate the phenomenon of concrete crushing failure of the joints of the bridge columns under the pseudo-static force of the segmental bridge columns,and can analyze the seismic performance of the segmental bridge columns qualitatively and quantitatively.(3)Because the unbonded prestressed tendons are an important part of the segmental hollow columns,the ratio of reinforcement,arrangement form,and the axial compression ratio of unbonded prestressed tendons are used as the research variables,the bridge columns in the form of different shear span ratios are combined,and the maximum displacement angle and residual displacement angle of the column top are taken as the research indicators.The response characteristics of the segmental hollow columns under the shock of near-field and far-field ground motion are analyzed by IDA analysis method,the change law of seismic response under earthquake action is determined,and reference suggestions are provided for the parameter design of the unbonded prestressed tendons in the segmental hollow columns.(4)Energy-dissipating steel bars,as the common energy-dissipating devices for segmental bridge columns,can improve the energy-dissipating performance of segmental bridge columns to a certain extent,but at the same time increase the residual displacement of bridge columns under earthquake action.At present,the influence of energy-dissipating steel bars on the seismic response of bridge columns under earthquake is unknown.Therefore,using the reinforcement ratio of energy-dissipating steel bars as the research variable,the influence of energy-dissipating steel bars on the seismic response of segmental hollow columns under earthquake action is investigated,and reference suggestions are provided for the reasonable setting of the reinforcement ratio of energy-dissipating steel bars in the segmental hollow columns.