Dynamic Behavior And Seismic Response Of A Long Span Partial Cable-Stayed Bridge

The He-Ma-Xi bridge is a long span partial cable-stayed bridge(PCTB) of a 230 m main span with concrete box girder, two towers and fan type cables in single plane, Which is currently the longest span highway PCTB under construction in china, This paper investigates the dynamic behavior and seismic response of the bridge. A three-dimensional finite-element model is first established for this bridge based on design drawings, The dynamic behavior are then analyzed from the statically deformed configuration, Such as the natural frequencies, mode shapes, and modal damping ratio. The seismic response of this bridge are also conducted to obtain time-history data of the deformation and internal force, The earthquake records are input in the bridge longitudinal direction, transverse direction, vertical direction and combined longitudinal and vertical directions or transverse direction. The analytical results show that dynamic characteristics are affected by the structural modification of the bridge engendered by static load including prestressing force, The seismic response behavior also depends highly on the characteristics of input records and three directions excitations should be considered.