Design of Main Arch of Hutiaomen Bridge on Guangzhou-Zhuhai Railway

The main bridge of the Hutiaomen Bridge on Guangzhou-Zhuhai Railway is a hybrid bridge of continuous rigid frame structure and flexible arch with span arrangement(120+248+120) m.The arch ribs of the bridge employ the concrete-filled steel tube structure formed by the upper,middle and lower chord tubes that are filled in with C50 concrete.Each of the arch ribs is composed of two parallel tubes and an inward inclined tube of basket handle and these tubes are connected into a three-leg(triangular) truss arch by the vertical and inclined web members,of which a vertical member is the rectangular steel box section while an inclined member is the round steel tube section.The arch ribs of the whole bridge have totally 19 cross bracings,the arch seats are the solid sections and the bridge is constructed by way of erecting the girder first and the arch late.The calculation of the bearing capacity,structural strength and stability behavior of the arch ribs is checked by the MIDAS Civil and the results of the checking prove that the static and dynamic behavior of the arch ribs can meet the relevant requirements in the codes.