Study of frictional slip of cable-saddle interface in three-pylon suspension bridge under the earthquake
In the three-pylon suspension tower,the main cable on both sides of the central tower is not connector to the anchor,leading to the relatively weak constraint to the main cable in longitudinal direction.The frictional slip at the cable-saddle interface is more prone to occur under the earthquakes.To explore the frictional slip at the cable-saddle interface and its influence on the seismic response of the three-pylon suspension bridge,this paper established a nonlinear finite element model of one typical three-pylon suspension,named Xunjiang Bridge.Frictional elements were used to reproduce the frictional slip at the cable-saddle interface,which well revealed different interfacial slip between the side and central pylons.The influence of the frictional coefficient on the local slipping behavior and global structure response was discussed.When the frictional coefficient was greater than 0.1,there was no frictional slip under design-based earthquakes,while under maximum considered and very rare earthquakes,the frictional slip occurred,and the peak slip decreased with increment of the frictional coefficient.The cable-saddle interface exhibited obvious hysteresis behavior,which provided a maximum equivalent damping ratio of about 2.0%under very rare earthquake.The contribution from the frictional force at the pylon top to the sectional moment at pylon bottom accounted nearly 50%-70%of its peak value for the side pylon.While for the central pylon,the contribution ratio was only 20%-40%due to its heavy self-weight and damping force at the deck height.It can be concluded that properly reducing the frictional coefficient was beneficial to the internal force of the pylons under earthquakes,but when the friction coefficient was reduced to 0.001,the main cable will lose its longitudinal constraint to the central pylon,and significantly altered the deformation mode and dynamic effects of the pylons.
three-pylon suspension bridgecable-saddle friction slipdynamic time history analysishysteretic curvefriction coefficient
万方数据
维普
