The Ductile Analysis And Desing Of Earthquake-resisting On Highway Girder Bridge

In China, the frequency of earthquake is higher, The loss of earthquake disaster occupy a higher ratio contrast to other nature disasters. How to assure the rehabilitation of lifeline engineering—bridge promptly is key to the rescuing after earthquake. The ratio of girder-bridge is higher than other styles. Most of them were designed to resist earthquake according to elastic theory .It can not make the best use of material characteristics. In allusion to present code deficiency, the following are some works done by author in this text.(1)The relation about reinforcing steel bar concrete between section curvature (curvature ductile coefficient) and bending moment, the ratio of axis pressure is analysis according to reinforcing steel bar, stress-strain relation and restriction concrete. So the function of main effect factor is decided, which can provide a method of earthquake-resisting and reinforcing design.(2)The earthquake reaction-equations of girder-bridge are established according to dynamics theory. The numerical value solution of structure three-dimension dynamic response analysis is established on the basis of sub-space alternate method and Wilson-θintegral, On the base of it the author workout a nonlinear earthquake response analysis program.(3)In this text, author analyses the earthquake response under different earthquake reactions, such as portrait earthquake response, landscape orientation earthquake reaction and rare earthquake response. During the analysis, each pier ductile coefficient is calculated according to adjust seismic waves amplitude and judge the pier earthquake-resisting ability. At last, the author put forward the reinforcing theory and frame chart of pier-reinforcing calculation under rare earthquake reaction.Through this research indicates that the seismic loading under the bridge structure of nonlinear analysis in order to correct description of the earthquake in the role of a bridge into the plastic stage of the state, the capacity of the bridge structure ductility. Flexibility to the theory of seismic design of the bridge, through non-linear analysis by ductility capacity judgement, usually their ability to improve earthquake once, after a reasonable reinforcement role in the rare event of the earthquake would not collapse. Under the strong earthquake, attention should be paid plastic hinge on the ability to design shear zones, to avoid shear failure in the first bend damaged. Vertical earthquake of a greater impact on the pier, in nonlinear analysis should take into account whether the choice of vertical earthquake input, to achieve the correct analysis of the request. Design should pay attention to strengthening horizontal design and conduct seismic design by ductility, the only way to achieve economic, security and practical. In addition, the seismic pier in the stirrups ductility play an important role, and that we should produce and design the importance of strengthening this kind of research.