Research On The Force Analysis And Optimal Design Of Segmental Precast Piers Of Small And Medium Span Bridges

The industrial construction and rapid assembly construction of bridge prefabricated components can accelerate construction speed,improve project quality and reduce the impact on surrounding environment.And it has become a national policy guidance and hot topic of industry research recently.Bridge prefabrication and assembly technology is widely used in the construction of superstructures.However,this technology is only used in the construction of very few bridge piers,and the existing connection scheme of segmental precast piers are mostly aimed at the special bridge,which is not suitable for large-scale use in a large number of small and medium span bridges.Therefore,in this paper,a series of studies have been carried out on the connection mode,structural form and force performance and so on of segmental precast piers of the small and medium span bridges.First of all,on the basis of consulting the domestic and foreign research literature,it's analyzed that the shortcomings of the current connection mode of segmental precast piers.And combined with engineering characteristics,a new type of connection mode of segmental precast piers is put forward which uses end plate welding connectors,whose structure form,structural advantage and overall design and so on are expounded,and the reliability of the connection is verified by test.Secondly,the finite element model of the whole bridge is built by MIDAS software,and the internal force distribution of the piers under different loads is analyzed.The weld depth of the connection part of piers is calculated.Based on the calculation results of the internal force of piers,the local model of segmental precast piers is established by ANSYS software,and the stress and deformation laws of each component under different load conditions are studied.Then,it's analyzed that the mechanical performance and seismic performance of segmental precast piers under static ultimate failure load and quasi-static cyclic displacement load by numerical simulation method.Taking the peak load capacity,ultimate bearing capacity,ductility performance,hysteretic performance,energy dissipation capacity and residual deformation of piers as indicators,the differences of the mechanical properties of segmental precast pier columns and the overall cast-insitu pier columns are studied.Finally,five measures are applied to optimize the design of segmental precast piers,such as changing the thickness of end plate and the depth of the weld,increasing the stiffening plate,annular hoop and core concrete.It's analyzed that the influence of different optimization measures on mechanical properties of piers.And it's introduced that the construction,transportation and installation of prefabricated components of segmental precast piers which have been optimized.The results show that the segmental precast piers which use end plate welding connectors in small and medium span bridges meet the requirements of structural design.The mechanical and seismic performance of the segmental precast piers under the static ultimate failure load and quasi-static cyclic displacement load are very similar to that of the overall cast-in-situ piers.Different optimization measures can improve the local and overall mechanical performance of the piers in varying degrees.In the small and medium span bridges,the usage of this kind of segmental precast piers can achieve the characteristics of high speed,high quality and high efficiency in industrial construction,and it has good social and economic benefits.