Bridge's Ductility Research Through Comparison Of Earthquake Resistant Codes Home And Abroad

Structure and component's inelastic deformation capacity before the obvious degradation of initial strength is ductility.Only using strength to resist seismic load is not economic,so we must design structure's ductility to absorb seismic energy and diminish losses.The present Code for seismic design of railway engineering carried out in Dec 2006,some problems have been exposed during WenChuan earthquake.As system research on different anti-earthquake codes home and aboard was made,after study on different provisions and its editing background,valuable suggestion how to provise present Code for seismic design of railway engineering was made.In this thesis,at first,through the summary of earthquake happened during the recent 15 years,the importance of earthquake fortification has bean proposed,thereout, thesis put forward the definition and significance in tbe ductility anti-earthquake of bridge structure;and then,from economic point of view,the significant of ductility anti-earthquake was exposited;followed the comparison of NTZ,1994,Caltrans, AASHTO,Eurocode 8,Code for seismic design of railway engineering,Guidelines for Seismic Design of Highway Bridges and its modifications,Japan's earthquake resistant design code for bridge.Ideas compared contain①Classification of bridges'importance②Level of seismic design and its purpose,③Methods used in earthquake fortification,④Classification of site,⑤Seismic force in different codes,⑥Design of plastic hinge,⑦Ductility index in different code,⑧Modeling methodology,⑨Ductility's checking computation.Through comparision,this thesis gives some suggests:①bridge should be divided into three levels:very important bridge,important bridge,common bridge.②Ductility reduction factor should be introduced into new code edition,through revising elastic spectrum,spectrum can be used to compute models which considering plastic behaviour.③Bridge model should divided into three types:rigid deck model,flexible deck model,individual pier model,just like Eurocode 8.Different usable condition should be given to different type of model.At last,according to the different earthquake resistant codes,different anti-earthquake calculation is presented,as well as the comparison of the computed results and conclusion on safe degree of different codes.