Simplified Analysis Of Seismic Performance And Research On The Influence Of Design Parameters Of Prestressed Segmental Bridge Columns

Precast segmental bridge columns have the advantages of good durability and short construction period,and they are less constrained by construction conditions,so they have unique advantages in bridge construction in urban and marine.By summarizing and analyzing the seismic performance analysis of precast segmental bridge columns so far,it is found that the main column form is that with centralized prestressed tendons,and the main research method is numerical simulation,although this method can calculate a more accurate result,it pends a lot of time and there are some shortcomings in the existing theoretical analysis methods for precast segmental bridge solumns.In order to improve the seismic performance of precast segmental bridge columns,prestressed tendons layout could be changed.In order to get the theoretical analysis method which could calculate a more accurate result,numerical regression analysis could be used to adjust the results of theoretical analysis.In order to improve the bearing capacity and energy dissipation capacity of traditional precast segmental bridge columns,column structure could be optimized.Based on the above three points,the main research works and conclusions are as follows:(1)Seven precast segmental bridge columns specimens are designed considering two research parameters including prestressed tendons layout and axial pressure ratio.The threedimensional solid element models are established by ABAQUS to perform seismic analysis.The effects of the prestressed tendons layout and the axial compression ratio on the hysteresis performance,energy dissipation capacity,joint opening,and stress and strain of the pier were discussed.The results of numerical analysis show that the lateral bearing capacity of the pier with scattered prestressed tendons is increased and the joint opening is smaller.After increasing the axial compression ratio,the energy dissipation capacity and lateral bearing capacity of the pier are significantly improved,and the joint opening has been reduced.(2)Deficiency in the existing theoretical analysis methods of prestressed segmental bridge columns are proposed,and the analysis process are modified to make the theoretical calculation results more accurate.31 bridge columns with different axial compression ratios are designed to perform numerical regression analysis on the yield force,yield displacement,and maximum force calculated by numerical simulation to obtain formulas.After correcting the theoretical force-displacement curves according to the formula,the corrected force-displacement curve is verified.Finally,the applicability of the simplified analysis method is analyzed.The analysis results show that the pier with lower initial stiffness needs to adjust the force-displacement curve through the correction formula to reduce the error,while the theoretical analysis result of the pier with larger initial stiffness is closer to the numerical analysis result.(3)According to the characteristics of weak energy dissipation of fully-segmented bridge columns,nine bridge piers were designed to optimize energy dissipation bars and slenderness ratios.The theoretical analysis method is used to calculate the bridge pier force-displacement curve and compared with the numerical simulation results to verify the feasibility of the theoretical analysis method.Through the numerical simulation calculation results,the effects of the length and diameter of the energy dissipation bars and the slenderness ratio of the pier on the hysteretic performance,energy dissipation capacity,residual displacement and joint opening of the pier are analyzed.The analysis results show that the lateral bearing capacity,energy dissipation capacity,and residual stress of the prestressed tendons of the pier are significantly improved after the bottom joints increase the energy dissipation bars.After reducing the slenderness ratio of the pier,the lateral bearing capacity and energy dissipation capacity of the pier are improved,but at the same time the joint opening and residual displacement have increased.