Design And Behavior Reseach On Emergency Reinforcement Anchor Syetem Of Lateral Pre-stressed Steel Wires For Bridge Piers

As a unit of road network,the bridge pier damage will seriously affect its security,which can reduce capacity of road network.At present,the traditional reinforcement method,although safe and reliable,has the shortcomings such as the large amount of work and the long period of reinforcement,which can't restore the traffic capacity of the bridge in short term.Therefore,this paper has developed a set of emergency reinforcement anchors of the pre-stressed steel wires for bridge pier,and carried out theoretical design and experimental study,The main contents include:1.The working principle and design method of the emergency reinforcement anchor of the pre-stressed steel wires for the bridge piers.The whole set of anchors consists of the anchor steel plate,high strength bolt,pre-stressed steel wire and the steel wire anchor.The steel wire hole of the anchor steel plate is designed by inclined hole,which can effectively reduce the local bending deformation of the steel wire.The calculation method of the length of the steel wire is studied,and the working coefficient of the steel strand is put forward to reflect the working condition of the steel wires.2.According to the theoretical analysis,the tension of the steel wire is in a linear relationship with the torque required to tighten the nut,and the pre-stress relation between the torque and the steel wires is obtained through the analysis of four test results.Torque6N·m and 15N·m are used to tighten the high strength bolts,6N·m loading efficiency is obviously better than 15N· m.3.The pre-stress loss caused by the working process of the anchor is studied.The theoretical derivation and experimental study of the friction loss formula of the steel wires is presented,and the results show that the friction loss increases with the increase of prestress level.For steel wires relaxation loss were studied,the relaxation losses within 5hours after loaded larger accounts for 60% of the total losses,20 hours after the steel wires relaxation to a halt,the relaxation losses ultimately is about 8%.Considering the relaxation losses of the steel wires,the steel wires is recommended to carry out 1.1 times exceed tension.4.Compared with not reinforced concrete short columns,the performance of bearing capacity,displacement ductility and energy dissipation capacity of strengthened withpre-stressed steel swire short column are improved.Compared with the intact specimen,the shear bearing capacity increased by 18%,the displacement ductility coefficient increased by 42%,and the energy dissipation capacity increased by 51% after the reinforced damaged specimen CC-100-0.2.Compared with reducing the spacing of the steel wires,the increase of the prestress level should be more obvious to the reinforcement effect.