Design of Xiaoshagou Bridge in Lanzhou

The main bridge of the Xiaoshagou Bridge in Lanzhou is a continuous rigid-frame bridge with span arrangement(57+2×100+57)m.The main girders of the bridge are of the corrugated steel webs and concrete composite box girders that have the single-cell single box cross sections and are arranged into two separate decks.For the corrugated steel webs,the Type 1600 corrugated steel plates are employed and the plates are connected with the top and bottom slabs of the box girders respectively by the PBL shear connectors and L200 angle bar connectors.The longitudinal prestressing tendons of the bridge are divided into two kinds of the internal and external tendons.The substructure has the frame structures that are made up of the left and right deck pier columns,pile caps and tie beams and are supported on the bored pile foundations.On the piers of the simply-supported ends of the side spans of the main bridge and the piers of the approach bridges,the high damping rubber bearings are arranged,on the abutments,the viscous dampers are arranged while on the transition piers,the shock transmission units are arranged.The main bridge is constructed by the scheme of cantilever in-situ casting and in the construction,the corrugated steel webs at the asymmetric segments of the side spans and at the closure segments are temporarily changed into the form travelers.The closure sequence of the bridge proceeds from the central span first and side spans late.The MIDAS Civil 2011 is used to conduct the static load and seismic resistance calculation and the results of the calculation prove that the various indices of the bridge can satisfy the relevant requirements in the codes.