Comparison of Seismic Design Schemes for Long-span Concrete Continuous Hhighway Girder Bridges

A long-span concrete continuous highway girder bridge usually has a large contin uous length and a heavy concrete girder with several bridge units.If it is buil t in a strong seismic zone,its seismic design is difficult.This paper introduc es the design concepts of earthquake-resistant-structure(ERS),isolation-str ucture(IS),and vibration-control-structure(VCS) for long-span concrete conti nuous highway girder bridges.The applicability of the three basic design concep ts is reviewed.Both the ERS and the IS design schemes were compared based on a case study.The results show that: comparing with the ERS design scheme,the IS design scheme can in average lower 56% longitudinal and 65% transverse horizonta l seismic force of the bridge substructure.The paper also discusses on the sele ction of seismic isolators,especially on the simplified method for calculating the initial design parameters of lead rubber bearing(LRB) during the concept de sign and preliminary design phases,which provide certain reference significance for similar projects.