Numerical Simulation And Theoretical Analysis On Seismic Performance Of Re-Centering Socketed Segmental Precast Pier

The precast piers gain research momentum due to its advantages of saving labor,accelerating construction,and having less impact on the environment.As an important infrastructure,seismic performance of bridges is critical to the rapid recovery and reconstruction after earthquake.Earthquake resilient structures can reduce structural damage,repairing cost,and risk of demolition,thus attracts increasing attention.At present,the development of precast piers has been limited due to inconvenience of construction,corrosion risk,and insufficiency of earthquake resilient performance.Based on the advantages of socketed pier and segmental pier,a new re-centering socketed segmental precast pier(RSSPP)was proposed in this paper.On the one hand,RSSPP with socketed connection has features of reliable connection,simple onsite construction and large tolerance,on the other hand,the pier has excellent re-centering performance because of post-tensioned prestress.Numerical simulation and theoretical analysis were developed in this paper.The detailed study contents are listed as follows:Due to the limitations of the existing segment bridge piers that required aerial operation,high accuracy requirements,long assembly time,and low durability,a new RSSPP which uses basalt fiber–reinforced polymer(BFRP)tendons and 2304 stainless steel bars was proposed.The pier is horizontally assembled in factory,and is connected on site.And structure construction,working principle,functional characteristics,and construction process of RSSPP were established.Based on literature data,two detailed finite element models of socketed pier and segmental pier were developed on Open Sees platform.Mechanical properties of two piers were evaluated,and simulated results were compared to experimental data.The results indicated that simulation and experiment were in comparative agreement,the simulation model was accurate and credible,and simulation method was available for RSSPP.Based on practical engineering,the model of RSSPP using BFRP tendons and 2304 stainless steel bars was established and analyzed.The influence of elastic modulus of tendon,initial prestress,reinforcement ratio of energy-dissipating(ED)bars,axial compression ratio of dead load,and shear span ratio were studied.The results showed that the shear span ratio and reinforcement ratio of ED bars had a significant effect on bearing capacity,and post-yield stiffness continuously increased with the rise of initial prestress.It was extremely obvious to improve the energy dissipation with the increasing the number of ED bars,but residual deformation raised subsequently.Thus,a balance between the re-centering performance and energy dissipation capacity need to be considered in practical application.The RSSPP pier was divided into load-bearing,post-tensioned tendons,and ED bars.The research from the behavior of bending,shear,expansion and overturning was carried out.According to calculation from simplified method of bearing capacity,the error between simulation and theory was very small,which verified the rationality of the theoretical calculating method.In addition,calculation formulas of ED bars and tendons was proposed.