Adaptability of Laying Ballastless Track on Long-span Continuous Steel Bridge of High Speed Railway
The main bridge of the Yellow River Bridge on the Xiongan-Shangqiu high speed railway(60+80+4×260+280+80+60)is a continuous steel truss flexible arch bridge with ballastless track laid on it,which has complex structural construction,long-span,high temperature sensitivity,and other characteristics.Taking the bridge as the object,the adaptability of laying ballastless tracks on high speed rail long-span continuous steel bridges was studied in this paper.A finite element model of the entire bridge space was established using MIDAS/Civil to analyze and study the vertical stiffness,beam end angle,bridge deck structure,beam end expansion device,and vehicle-rail-bridge coupling vibration dynamic response.The results indicate that the structure of steel truss flexible arch can provide significant vertical stiffness for ballastless tracks,ensuring smooth and safe driving.The use of shorter side span combinations can effectively reduce the beam end angle.The smoothness of the track surface of concrete bridge decks with broken joints is better than that of continuous bridge decks without broken joints.Under the same shear safety factor,the connection between the concrete cushion layer and the steel bridge deck using cylindrical shear studs is more economical than PBL(Pre-tense Bolted Locked-up)shear keys.Based on the calculation of beam end deformation,it is recommended to choose a steel rail expansion adjuster with an expansion of±600 mm,which can meet the deformation requirements of this bridge end.Through the dynamic simulation analysis of vehicle-track-bridge coupling vibration,the various dynamic performance indicators and ride comfort of the bridge meet the regulatory requirements.
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