Research On The Impact Of The Development Of Plasticity To Seismic Performance Of Bridges

The sequence of plastic hinge appearing in engineering has great imPact forstructural. In strong earthquakes, the plastic hinge is generally carried out at thebottom of the piers, secondly it concentrates in the top of the pile and the mainbeam.Having The Third Nanjing Yangtze River Bridge as a background, the worksare carried out with the following aspects in this Paper:(1) Three different types of seismic waves: El-Centro wave, Tianjin wave andNanjing waves are considered to be input ground motion. Through the analysis ofdynamic characteristics of four piles, the residual deformation of pile top is0.04mwhen inputting El-Centro wave. The peak displacement of1/11section is0.19mand0.20m, the peak acceleration is210Gal and190Gal, both are50%and10.5%difference when respectively inputting Tianjing wave and Nanjing wave.(2) The characteristics of high-energy pulsed, directional effects and largervertical acceleration are embodied in near-fault earthquake. Though studying thehysteretic energy and order of appearance of plastic hinges under three cases ofdifferent pile diameters when inputting Tianjing wave, the result shows that themain plastic hinge appears at the bottom of tower, sub-plastic hinge appears in theinterface of pile and soil when the diameter of pile is3.0m and2.4m, the residualdeformation is respectively0.05m and0.06m.The plastic hinge only appears inthe pile, and in this case the residual deformation of the tower is0.28m when thediameter of pile is2.0m.(3) The period of velocity and acceleration pulse of far-field earthquake islonger. Considering the T1-II-1wave to be input ground motion, the result showsthat the residual deformation of the tower of the three calculation models is2.4,2.8and1.3times and the maximum reaction curvature of plastic hinge is1.6,2.1and1.5times in terms of the situation of near-field earthquake. The biggestincrease of bending moment of piles is36.5%.