Numerical Analysis Of Seismic Performance Of Segmental Bridge Pier With Mortise-and-Tenon Joints

Precast segment-assembled pier has the advantages of high construction efficiency and small disturbance to the surrounding environment,and it is widely used in areas with low seismic fortification intensity.However,because there are still many shortcomings in the research of seismic performance,it is rarely used in areas with high seismic fortification intensity.In the existing studies,the shear behavior and plastic hinge uplift phenomenon of segment assembled bridge piers under seismic action are rarely considered.In this paper,the moment-curvature analysis is carried out on the assembled pier under lateral force.A new type of jointed pier,namely mortise-and-mortise jointed pier,was proposed,and its seismic performance was numerically analyzed with ANSYS finite element analysis software.The specific work and conclusions are as follows:(1)Firstly,the response of segment-assembled pier under lateral force is analyzed.According to the change of neutral axis width on the contact surface between segments,the response process is divided into three stages,and the bending moment-curvature analysis of the lower segment-assembled pier in different stages is carried out.The first two stages only need to consider the plastic hinge formed at the contact surface between the bottom segment and the foundation.In the third stage,when the plastic hinge moves upward,the influence of plasticity at the contact surface between the lowest two segments should be considered.On the basis of considering the influence of plastic hinge moving up,the analysis steps of moment-curvature analysis of segment assembled bridge piers are analyzed and explained in detail.And the calculation method of horizontal displacement of pier top in each stage is given.(2)12 kinds of working conditions are designed according to tongue material,prestress value and ratio of energy-consuming reinforcement.The tenon materials are reinforced concrete and steel,the prestress values are 0,0.05fcAg and 0.10fcAg,and the ratio of energy-dissipating bar is 1.05%and 2.05%.The finite element analysis software ANSYS was used to analyze the specimens under 12 working conditions.(3)The results show that the increase of prestress reduces the ductility and hysteretic energy dissipation,but has little effect on the shear capacity.The increase of prestress will improve the re-centring performance of components.Meanwhile,the re-centring performance of components connected by steel tenon is more susceptible to the change of prestress value,because the size of steel tenon is smaller and the interaction between segments is smaller.The increase of the reinforcement ratio of energy-dissipating bars can improve the shear capacity and hysteretic energy dissipation performance of components,but reduce the ductility and re-centring performance of components.(4)Considering the influence of the three factors on the seismic performance of the specimens,the reasonable range of the prestress and the ratio of the energy-dissipating reinforcement of the assembled pier with different tenon materials is given.The prestress value of the members connected by reinforced concrete tongue was set as 0.05fcAg,and the ratio of energy dissipated reinforcement was 1.05%.For members connected by steel tongue,the value of prestress ranges from 0 to 0.05fcAg,and the reinforcement ratio of energy-consuming steel ranges from 1.05%to 2.05%.