Design of Guangya Bridge in Liuzhou City

With a view to suit the aesthetic and functional requirements of urban bridges,the Guangya Bridge in Liuzhou city is designed as a gull-shaped steel box arch bridge.The main bridge,with span arrangement of(63+2×210+63)m,is a half-through steel box arch bridge which has two continuous spans of arches.The main bridge belongs to a rigid-frame tied arch bridge structure system,the two arch ribs are connected transversely by lateral bracings only at the level of bridge deck,and secondary arch ribs are added to the side spans.The arch ribs adopt the catenarian steel box arch with variable cross section and with a net rise-to-span ratio of 1/4. The triangular oblique rigid-frame legs are the extension of the main span arch ribs with the same geometrical shape.The main girder adopts the orthotropic grillage deck system formed of stringers and transverse beams,with opening on the base plates.A number of 32pairs of hangers,which are composed of steel strands with epoxy coatings and extruded to take shape from a whole bundle of strands,are installed with a spacing of 9malong the bridge length.Besides,a number of 8tie bars,also made up of steel strands with epoxy coatings and extruded into shape from a whole bundle of strands are installed.The MIDAS software was used to set up the spatial model of the main bridge to calculate its mechanical performance.The results of the calculation show that the strength,rigidity and stability of the bridge all meet the requirements.