The Allowed Plasticity Ratio In Ductility Design

This article introduced the damage of bridge in earthquake and analyzed the cause of the damage and made some suggestions to cut down the damage of bridge in earthquake.It also introduced the development of seismic design and the advantages and disadvantages of static method,the response spectrum and time-analysis method.This article introduced the conception of ductility and the ductility design,depict the definition and calculation method of the displacement ductility coefficient.It compared the bridge seismic design among the U.S.A,Japan,Europe and China.It described the definition,calculation method and factors of the allowed plasticity ratio and compared it with the displacement ductility coefficient.We changed the shape and dimension of section volumetric longitudinal bars ratio,axial compression ratio,volumetric transverse reinforcing steel ratio and the concrete strength and used Xtract software to calculate yield curvature and ultimate curvature in different conditions. So we can use numerical value calculate the allowed plasticity ratio and the displacement ductility coefficient and find the change of them and the connection between them. So we can choose the appropriate numerical value of factors to ascertain the allowed plasticity ratio and make sure the structure have enough ductility.